ROYAL ACADEMY OF MEDICINE IN IRELAND IRISH JOURNAL OF MEDICAL SCIENCE
4th Annual Meeting Frontiers in Neurology Friday 21st November 2014, Dublin, Ireland
Irish Journal of Medical Science Volume 184 Supplement 1 DOI 10.1007/s11845-014-1239-4
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
Disclosure Statement Prof. Kumlesh K. Dev is supported by research grants from Novartis Ireland and Novartis Basel Switzerland. Royal Academy of Medicine in Ireland 2015
Prof. Kumlesh K. Dev, Drug Development, School of Medicine, Trinity College Dublin, IRELAND Tel: +353 1 896 4180 email: [email protected]
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
Sponsorship The conference was supported by Novartis Ireland, Science Foundation Ireland, Block MS Ireland and in kind by Cisbio Assays, Health Research Board and Trinity College Dublin.
ROYAL ACADEMY OF MEDICINE IN IRELAND
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
Meeting Programme Main Lecture Hall 11.00
Registration and Poster Setup
Coffee Break and Poster
Welcome, Prof. Kumlesh K. Dev
Plenary Lecture: Prof. Jack Antel (McGill University, Montreal QC, Canada): The potential for tissue repair in multiple sclerosis
SFI Lecture: Prof. Trevor Owens (University of Southern Denmark): Microglial regulation of CNS inflammation
Lunch and Poster Viewing
Parallel Session 1 (14.30–15.40): Cellular Mechanisms Chairs: Prof. Kumlesh K. Dev and Prof. Marina A. Lynch 14.30–14.45
Dr. Florian Muellershausen (Novartis, Basel, Switzerland): Translating the cellular effects of S1P receptors to physiological function
Thomas O’Hagan & Dr. Denise Fitzgerald (Queens University Belfast, UK): Role of T regulatory cells (Tregs) in CNS remyelination
Dr. Una Fitzgerald (University of Galway, Ireland): Endoplasmic reticulum stress: jack of all trades in multiple sclerosis
Studio Lecture Room Parallel Session 2 (14.30–15.40): Clinical Studies
Dr. Anna Molloy & Dr. Niall Tubridy (St Vincent’s Hospital, Dublin, Ireland): Environmental fcators and aetiology of primary torsion dystonia
Dr. Russell McLaughilin & Prof Orla Hardiman (Beaumont Hospital, Dublin, Ireland): Using identity by decent to find new genes in neurological disease
Prof. Shiv Saidha (Johns Hopkins University, Baltimore, USA): Optical coherence tomography in MS; retinal pathology reflects global CNS disturbances
SFI Lecture: Prof. Patrick Vermersch (University of Lille, France): Is long term disability in MS related to inflammation?
Plenary Lecture: Prof. Tim Lynch (Mater University Hospital, Dublin, Ireland): Movement and movement disorders
Poster Prizes, Dr. Aisling Ryan
Closing Remarks, Prof. Kumlesh K. Dev
Local Organising Committee Prof Orla Hardiman, Dr. Aisling Ryan, Prof. Kumlesh K. Dev.
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 DOI 10.1007/s11845-014-1239-4
1 Plenary Lecture S1.1. Potential for tissue repair in multiple sclerosis Jack Antel Neuroimmunology Unit, Montreal Neurologic Institute, McGill University Demyelination with inflammation is the hallmark of acute lesions underlying relapses in MS. Clinical recovery reflects resolution of inflammation, axonal re-organization, and remyelination. Histologic and magnetic resonance studies document variable remyelination in individual lesions and cases. As the disease course evolves, there is less evidence of ongoing remyelination, further axonal loss, and more extensive gliosis. Remyelination depends on the intrinsic properties of myelinating cells, presence of axon targets, and local environmental cues. The robust remyelination found in experimental studies are attributed to oligodendrocyte (OL) progenitor cells (OPCs) rather than previously myelinating OLs; however most models feature extensive OL destruction. Differentiating OPCs are present in acute MS lesions; to be considered is that some may be destroyed or functionally disabled by the same mediators that induce death/injury of mature OLs. As disease progresses, OPC numbers and differentiation decrease. Thus early neuroprotective strategies may both prevent injury and promote repair. Concern regarding numbers and capacity of endogenous myelin lineage cells provides a rational for exogenous cell replacement. Signals derived from the MS lesion environment can be positive or inhibitory. Sources of such molecules include infiltrating immune cells and endogenous glia, astrocytes and microglia. Each can regulate the molecular profiles of the others and also respond to products released by damaged myelin lineage cells. The emergence of therapeutic agents that access the CNS, raise the possibility of enhancing the remyelination process both by acting directly upon myelinating cells and/ or indirectly via the immune-glial networks.
S1.2. Microglial regulation of CNS inflammation Trevor Owens, Reza Khorooshi, Marlene Mørch, Agnieszka Wlodarczyk, Camilla Hermansen, U. Muscha Steckelings1 Neurobiology, and 1Cardiovascular and Renal, Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark Microglia regulate the inflammatory milieu in the CNS. They recognize pathogen and danger signals via innate receptors and they are a source of pro-inflammatory cytokines such as IL-1b and Th1- and Th17-inducing IL-12 and IL-23, and chemokines. They are also a source of counter-inflammatory or neuroprotective mediators such as Type I Interferons (IFN) and Insulin-like Growth Factor-1. Microglial cross-talk with astrocytes includes dependence of astrocytes on microglia for TLR response, and chemokine-driven responses. We study endogenous anti-inflammatory pathways within the central nervous system (CNS), with a goal to be able to access them for clinical benefit in multiple sclerosis (MS) and neuromyelitis optica (NMO). Both glial and immune pathways are being pursued. MS and its animal model experimental autoimmune encephalomyelitis (EAE) are inhibited by peripheral IFNb, whereas IFNb is detrimental for NMO. We find that intra-CNS induction of IFNb using PAMP’s to trigger macrophages and microglia suppressed EAE, and this did not
occur in IFNAR-deficient mice. Glial response included production of IFN-dependent chemokines and IRF7. The Type II angiotensin receptor (AT2R) also induces neuroprotective responses. We study effect of an AT2R-specific agonist as well as AT2R deficiency on NMO-like disease in mice. Although AT2R-KO mice developed similar NMO pathology to wild-type, they showed defects in neurotrophin response, identifying potential mechanism for protective effect of the agonist. In studies of functional microglial heterogeneity, we focus to a CD11c? subset that are also potentially neuroprotective. These topics will be discussed with reference to recent data. Acknowledgments: Research supported by the Danish Council for Independent Research, Lundbeck Foundation, The Region of Southern Denmark, Danish Multiple Sclerosis Society.
2 Cellular Mechanisms S2.1. Translating the cellular effects of S1P receptors to physiological function F. Mu¨llershausen, E. Wallstrom, P. Gergely Novartis Pharma AG, Basel, Switzerland Sphingosine-1-phosphate (S1P) is a pleiotropic messenger molecule acting mainly through G protein-coupled cell surface receptors, S1P receptors 1–5. Expression of S1P receptors and downstream signaling events have been shown to trigger functional responses in neuronal cells, astrocytes, endothelial cells, cardiac myocytes and lymphocytes. Transgenic mice and pharmacological agents selectively targeting S1P receptors have greatly helped translating cellular responses into physiological function. Those studies demonstrated that many of the most obvious physiological responses were mediated by one of the family members of the S1P receptors, the S1P1 receptor. The S1P1 receptor was found to play an important role in the egress of lymphocytes from secondary lymphoid organs. Pharmacological intervention at the S1P1 receptor led to a redistribution of lymphocytes from the peripheral blood to lymphoid tissues. Based on this finding, S1P1 receptor ligands were assessed in various animal models of autoimmune diseases with lymphocyte involvement, where they showed impressive efficacy. Eventually, the principle was evaluated in clinical trials showing benefit in the treatment of relapsing-remitting multiple sclerosis. BAF312 (Siponimod) is a selective agonist at S1P1 and S1P5 receptors which is currently undergoing clinical trials in patients with multiple sclerosis and inflammatory myopathies. This experimental drug can be considered a poster child for the translation of molecular findings into cellular and physiological function in animals and eventually into clinical application.
S2.2. Role of T regulatory cells (TREGS) in CNS remyelination Thomas P. O’Hagan1, Yvonne Dombrowski1, Marie Dittmer1, Peter Bankhead2, Chao Zhao3, Rachel Hassan1, Ingrid V. Allen1, Peter Hamilton2, Adrien Kissenpfennig1, Rebecca J. Ingram1, Robin J.M. Franklin3 and Denise C. Fitzgerald1 1 Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Science, Queens University Belfast, Northern Ireland, UK. 2Centre for Cancer Research and Cell Biology, School of
S6 Medicine, Dentistry and Biomedical Science, Queens University Belfast, Northern Ireland, UK. 3Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, England, UK Multiple Sclerosis (MS) is an immune-mediated disease, characterised by demyelination in the central nervous system (CNS). In MS, repair of myelin sheaths (remyelination) can occur. However, when this regenerative process fails patients can develop permanent disability. The promotion of remyelination is currently an unmet clinical need that holds significant potential to improve the lives of MS patients. Despite the pathological role of CD4? T cells in MS, T cells have been shown to support remyelination in experimental models. However, previous studies investigated total CD4? T cells without addressing distinct CD4 ? subsets. Thus, we aimed to characterise the role of the anti-inflammatory CD4? T cell subset, regulatory T cells (Treg), in CNS remyelination. Selective depletion of FoxP3? Treg significantly impaired oligodendrocyte differentiation following toxin-induced demyelination in murine spinal cord in vivo. To determine if Treg acted directly on neural cells we utilised an organotypic brain stem slice model that myelinates ex vivo. In both inflammatory and stabilized brain slice cultures, Treg and/or conditioned media from Treg cultures promoted the maturation of oligodendrocytes, developmental myelination and remyelination as measured by co-localisation of fluorescent staining of myelin and axons. Proteome profiling of conditioned media identified a novel Treg-derived factor that, when neutralised, abrogated Treg-induced oligodendrocyte differentiation and myelination in glial cultures and brain slices. These findings uncover a new role of Treg in promoting oligodendrocyte differentiation and myelin regeneration in the CNS, distinct from, but complementary to, classical anti-inflammatory roles of Treg. Acknowledgments: This work was supported by the Biotechnology and Biological Sciences Research Council, the Department of Employment and Learning (Northern Ireland), The Leverhulme Trust and the British Neuropathological Society.
S2.3. Endoplasmic reticulum stress: jack of all trades in multiple sclerosis Jill McMahon, Michelle Naughton, Sinead Healy, Una FitzGerald National University of Ireland, Galway Correct folding of secreted and membrane-destined cellular proteins occurs in the endoplasmic reticulum (ER). The smooth ER is also a major site of lipid synthesis. Many folding- and lipid synthesisassociated proteins are dysregulated during disease, leading to a logjam of mis-folded proteins within the ER. Normal physiological needs may also place an increased demand on the ER. The cellular response to an increased ER burden is called the unfolded protein response (UPR), or ER stress. Here we report significantly raised levels of ER stress-associated proteins within human post-mortem MS brain tissue and in spinal cord samples from an animal model of inflammatory demyelination. A quarter of the MS cases studied also had significantly higher levels of a marker of hypoxia. Moreover, the ER chaperone calreticulin was detected at significantly higher levels in the serum of some patients with MS, prompting us to expand our investigation of ER chaperones as potential biomarkers in MS. Finally, because myelin is comprised of a mixture of lipids and membrane proteins, we have quantified levels of ER stress proteins within normal developing white matter tracts. Data has suggested a novel role for ER proteins ATF6, p-IRE1, GRP94, GRP78 and PDI, in normal myelination. Collectively, our data highlights ER stress
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 signaling pathway proteins, as ‘Jack of all trades’ molecules, potentially having important roles in MS pathogenesis and myelination, and representing possible novel MS biomarkers. The need to develop ERstress pathway-targeting therapies for individuals with MS and to further explore ER stress proteins as novel biomarkers is clear. Acknowledgments: The authors gratefully acknowledge the assistance of the Foundation Office, NUIG; MS Ireland and the HRB (Grant ref MRCG/2011/21; the UK MS Society (Grant ref 833/05); the UK Multiple Sclerosis Tisue Bank, funded by the Multiple Sclerosis Society of Great Britain and Northern Ireland, registered charity 207495; Action MS (Northern Ireland). We also wish to thank Dr. Brian Heron, Neuropathology, Royal Group of Hospitals Trust, Belfast, for the initial training in the identification of grey matter pathology. The authors also acknowledge the technical assistance of Dr. Peter Owen and Prof. Peter Dockery of the Centre for Microscopy and Imaging, at NUI Galway.
3 Clinical Studies S3.1. Environmental factors and aetiology of primary torsion dystonia Anna Molloy, Niall Tubridy Anna Molloy1,2, Laura Williams 1,2, Okka Kimmich1,2, John S Butler3, Ines Beiser1,2, Eavan McGovern1,2, Sean O’Riordan1,2, Richard B Reilly3, Cathal Walsh4,5, Michael Hutchinson1,2 1 Department of Neurology, St. Vincent’s University Hospital, Dublin, Ireland. 2School of Medicine and Medical Science, University College Dublin, Ireland. 3Trinity Centre for Bioengineering, Trinity College Dublin, Ireland. 4Department of Statistics, Trinity College Dublin, Ireland. 5Department of Mathematics and Statistics, University of Limerick, Ireland
Adult-onset isolated focal dystonia (AOIFD) may present with various phenotypes including blepharospasm and cervical dystonia. Although inherited in an autosomal dominant manner with a markedly reduced penetrance, environmental factors are considered important in both disease penetrance and expression. We performed two studies to assess the role of the environment in belpharospasm and in cervical dystonia further. A case–control study of 67 patients with cervical dystonia and 67 of their age-matched unaffected siblings was performed using a questionnaire. We found that car accidents with hospital attendance (OR 7.3, 95 % CI 1.4–37.6, p = 0.017) and all surgical episodes (OR 4.9, 95 % CI 1.24–19.31, p = 0.023) were significantly associated with case status. We concluded on this basis that soft tissue trauma appears to increase risk of development of cervical dystonia in genetically predetermined individuals. In a second study, we hypothesised that sun exposure is an environmental risk factor for the development of blepharospasm in genetically susceptible individuals. From published clinic cohorts and epidemiological reports, the ratio of the number of cases of blepharospasm to cervical dystonia (phenotype case ratio) at each study site was analysed. Metaregression of the phenotype case ratio in 15 eligible study sites over 41 degrees of latitude demonstrated a statistically significant inverse association with latitude (p = 0.0005, R2 = 52.58 %). There were significant positive associations between the phenotype case ratio and quarter-one (January-March) solar insolation (p = 0.0008, R2 = 50.1 %) and average annual solar insolation (p = 0.0043, R2 = 38 %). The increase in the blepharospasm: cervical dystonia case ratio with decreasing latitude and increasing insolation suggests that sunlight exposure is an environmental risk factor for the
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 development of blepharospasm (rather than cervical dystonia) in individuals genetically susceptible to adult-onset dystonia. Acknowledgments: This study was supported by grants from Dystonia Ireland, a patient support organization, the Irish Institute for Clinical Neuroscience, the Foundation for Dystonia Research (Belgium) and the Health Research Board, Ireland, Clinical Scientist Award (CSA-2012/5).
S3.2. Using identity by descent to find new genes in neurological disease Russell McLaughlin, Orla Hardiman Unit of Neurology, Trinity Biomedical Sciences Institute, Trinity College Dublin Despite being highly heritable, amyotrophic lateral sclerosis (ALS) only presents with a discernible family history in around 10 % of cases. In a proportion of the remainder of cases, termed sporadic ALS, genetic aetiological factors play a role, the majority of which remain to be elucidated. Identification of novel genetic risk factors is facilitated by known relationships amongst affected individuals. Genomewide single nucleotide polymorphism data can be used to infer relationships amongst individuals; methodologies based on haplotype phasing and identity-by-descent (IBD) inference have high sensitivity to detect relationships conferring shared segments representing very small fractions (\1 %) of the genome. We have mapped pairwise IBD segments in an Irish ALS case–control cohort along with a large British control cohort and used total genomic length IBD as a measure of relatedness between pairs of individuals. Comparison between Irish and British populations demonstrates a higher level of IBD within Irish individuals compared to the British. Furthermore, total genomic length of pairwise IBD is correlated with the geographical distance between individuals. By mapping IBD segments, a large number of familial relationships were revealed between individuals previously assumed to be unrelated. Heirarchical clustering of individuals based on pairwise values for total genomic length IBD revealed several clusters of inter-related individuals representing multiple members of the same pedigrees. This challenges existing ideas about the distinction between sporadic and familial forms of ALS and provides a methodological framework for the use of genome-wide datasets from unrelated individuals in the design of family-based genome sequencing experiments. Acknowledgments: We thank all patients who participated in the study and their families, as well as all controls who generously donated samples. This research has received support from the Health Research Board of Ireland, Fondation Thierry Latran, the ALS Association of America and the European Health Seventh Framework Programme (FP7/2007–2013) under grant agreement n 259867.
S3.3. Optical coherence tomography in ms; retinal pathology reflects global CNS disturbances Prof. Shiv Saidha Johns Hopkins University School of Medicine, Baltimore, USA Optical coherence tomography (OCT) segmentation derived ganglion cell layer ? inner plexiform layer (GCIP) thickness has been shown to have superior structure–function relationships to conventional
S7 peripapillary-retinal nerve fiber layer (RNFL) thickness in multiple sclerosis (MS). Although thicknesses of both of these structures correlate with expanded disability status scale (EDSS) scores and wholebrain volume cross-sectionally, it has been unclear whether retinal and brain atrophy progress concomitantly with one another in MS. Similarly, inner nuclear layer (INL) thickness has been shown to potentially predict inflammatory activity in MS, but whether INL changes and lesion accumulation are related over time has been unclear. In a four year study of 107 MS patients we found that rates of GCIP and wholebrain (r = 0.45, p \ 0.001), gray matter (r = 0.37, p \ 0.001), white matter (r = 0.28, p = 0.007) and thalamic (r = 0.38, p \ 0.001) atrophy were associated. GCIP and whole-brain (as well as gray matter and white matter) atrophy rates were more strongly associated in progressive MS (r = 0.67, p \ 0.001) than relapsing-remitting multiple sclerosis (RRMS, r = 0.33, p = 0.007). However, correlation between rates of GCIP and whole-brain (and additionally gray matter and white matter) atrophy in RRMS increased incrementally with stepwise refinement to exclude optic neuritis effects; excluding eyes and then patients (to account for a phenotype effect) the correlation increased to 0.45 and 0.60 respectively, consistent with effect modification. In RRMS, lesion accumulation rate was associated with GCIP (r = -0.30, p = 0.02) and INL (r = -0.25, p = 0.04) atrophy rates. Results of this study suggest GCIP atrophy mirrors whole-brain, and particularly gray matter atrophy, especially in progressive MS, thereby reflecting underlying disease progression. Acknowledgments: Race to Erase MS.
4 Plenary Lecture S4.1. Is long term disability in MS related to inflammation? Patrick Vermersch University of Lille Nord de France, Lille, France Relapses are the hallmarks of the relapsing-remitting (RR) form of multiple sclerosis (MS). They may produce temporary or even permanent loss of function, but most disability results from the relentless progressive phase of the disease. Among secondary progressive (SP) phenotypes, the total number of attacks does not influence time to expanded disability status scale (EDSS) 6, 8 and 10, i.e. using a cane, bedridden and death from MS. Despite no association between total relapses and later progression of disability, there is a clear association for early relapses. It is possible that suppression of relapses in year 1 and 2 might modify the progressive phase, potentially decreasing long-term disability. It is well documented that disability accumulation in multiple sclerosis is correlated with axonal injury and that the extent of axonal injury is correlated with the degree of inflammation. However, the interdependence between focal inflammation, diffuse inflammation and neurodegeneration, and their relative contribution to clinical deficits, remains ambiguous. It is generally believed that acute MS lesions are initiated by a myelin reactive CD4 T cell that is stimulated in the periphery and enters the brain and spinal cord. In these lesions, the CD8 T cells play a critical role, in combination with B cells and macrophages. Their contribution to the disability is accepted related in part to the disconnections between multiple brain areas. For the long term disability, it is highly probable that the innate immunity (microglial cells, astrocytes,…) plays a major role in the neurodegenerative process. In conclusion, long term disability may result as the consequence of complex interplays between adaptative/ innate immunity dysfunctions leading to neuronal degeneration.
S4.2. Movement and movement disorders
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
P5.2. Expression and functional analysis of nucleic acid sensors in astrocytes and microglia
Tim Lynch The Dublin Neurological Institute at the Mater Misericordiae University Hospital and University College Dublin Genetics and immunology are leading to some of the biggest changes in medicine and science both from understanding the pathogenesis of the disease but also providing novel therapeutic approaches in humans. Movement disorders are common and a great asset in the localization of disease in the nervous system but also assist in the differential diagnosis. The applications of genetics and immunology to movement disorders is leading to many new genetic diagnoses but also novel therapeutics. Prof Lynch’s talk will attempt to demonstrate movement disorders using videotapes of individual patients and the relevance and application of genetics and immunology to the diagnosis and treatment of the same patients. The talk is expected to be interactive.
5. Posters P5.1. Spinal cord grey matter abnormalities are associated with secondary progression and physical disability in multiple sclerosis H. Kearney1, T. Schneider1, M.C. Yiannakas1, D.R. Altmann1,2, C.A.M. Wheeler-Kingshott1,3, O. Ciccarelli1,3, D.H. Miller1,3 1 NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, UK; 2 Medical Statistics Department, London School of Hygiene & Tropical Medicine, London, UK; 3NIHR University College London Hospitals Biomedical Research Centre, London, UK
Presenting Author: Hugh Kearney: [email protected]
Background: In multiple sclerosis (MS), pathological studies have identified substantial demyelination and neuronal loss in the spinal cord grey matter (GM). However, there has been limited in vivo investigation of cord grey matter abnormalities and their possible functional effects using magnetic resonance imaging (MRI) combined with clinical evaluation. Methods: We recruited healthy controls (HC) and people with a clinically isolated syndrome (CIS), relapsing remitting (RR) and secondary progressive (SP) MS. All subjects had 3T spinal cord MRI with measurement of cord cross-sectional area and diffusion tensor imaging (DTI) metrics in the GM and posterior and lateral column white matter (WM) tracts using region of inregulates myelin development and inhibitsterest analysis. Physical disability was assessed using the expanded disability status scale (EDSS) and motor components of the MS functional composite scale. We calculated differences between MS and HCs using a t test and associations with disability using linear regression. Results: 113 people were included in this study: 30 controls, 21 CIS, 33 RR and 29 SPMS. Spinal cord radial diffusivity (RD), fractional anisotropy and mean diffusivity in the GM and posterior columns were significantly more abnormal in SPMS than in RRMS. Spinal cord GM RD (p0.01) and cord area (p0.01) were independently associated with EDSS (R2 = 0.77); spinal cord GM RD was also independently associated with 9-hole peg test (p0.01) and timed walk (p = 0.04). Conclusion: The study findings suggest that pathological involvement of the spinal cord GM contributes significantly to physical disability in relapseonset MS, and SPMS in particular.
Donal Cox1, Glyn Williams1, Robert Field3, Marcin Baran2, Andrew Bowie2, Colm Cunningham3, Aisling Dunne1 1
Molecular Immunology Group, School of Biochemistry & Immunology; 2Viral Immune Evasion Group, School of Biochemistry & Immunology; 3Neurodegeneration and CNS Inflammation Group, School of Biochemistry and Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland Presenting Author: Donal Cox [email protected]
The recognition of nucleic acids is essential for combating viral and bacterial pathogens. The sensors and pathways involved in RNA/ DNA detection have only recently been discovered and have expanded over the last number of years. TLR9 was the first DNA sensor to be discovered followed by the cytosolic DNA receptors which include members of the PYHIN family, DAI and the enzyme cyclic GMPAMP synthase (cGAS). The PYHIN family are so called as they contain an N-terminal PYRIN domain and a C-terminal HIN domain. These proteins bind DNA directly via their HIN domains culminating in the production of anti-viral and pro-inflammatory cytokines. Microglia and astrocytes can respond to cytosolic poly (I:C), via RIGlike receptors, however the contribution of DNA sensors has not been fully explored in neuroimmune cells. Furthermore, the contribution of individual cell types, in particular astrocytes, has been confounded by difficulties in obtaining pure populations devoid of contaminating microglia. Finally, most studies reported to date have used poly(dA:dT) as a DNA mimetic, however this can be reverse transcribed to RNA by RNA pol III and is capable of activating RNA sensors. We have carried out extensive expression profiling of the newly described DNA sensors in purified astrocytes and microglia and have found that both cell types have the capacity to induce a strong anti-viral response in the presence of immune stimulatory DNA and RNA. Furthermore we have found that key sensors are upregulated in a murine model of neurodegeneration and this is dependent on the type I interferon, IFNbeta.
P5.3. Axon guidance: the roles of radial glial cells and novel guidance cues in spinal cord formation Albert Kelly, Aisling Omalley, Denis Barry Department of Anatomy, Trinity Biomedical Science Institute, Trinity College Dublin Presenting Author: Albert Kelly [email protected]
Spinal cord injury (SCI) carries life-long physical and psychological impacts. A natural healing process can occur across the lesion site, however the regrowth of axons is highly disorganised leading to poor outcome. A better understanding of the signalling cues underlying axon growth during developing would enhance current treatment strategies. This study aims to investigate the roles of radial glia and Semaphorin6A (Sema6A) in the spinal cord. Semaphorins are the largest family of axonal guidance cues, while radial glial cells are vital progenitors, scaffolding the developing CNS. Sema6A plays vital roles in the guidance of growing axons in the brain and its deficiency is linked with autism and schizophrenia, however its role in the spinal cord is relatively unknown. Here the distribution and function of these guidance mediators were characterised at key stages of axonal growth in the mouse. A highly organised and conserved
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 radial glial scaffold is described, suggestive of axonal guidance roles. Deletion of Sema6A from the mouse results in increased sensory axon input into the spinal cord through the dorsal roots. Conversely, deletion of the canonical Sema6A receptor PlexinA2 results in a reduction of sensory axon input. This demonstrates that Sema6A is repulsive to sensory axons entering the spinal cord and that this effect is independent of its receptor PlexinA2. Taken together, these finding show an important role for radial glia and Sema6A in the guidance of developing axons, providing valuable insights and motivations for further research, that may be useful in the context of SCI axon regeneration.
P5.5. Detection of astrocytic autoantibodies in the csf of patients with multiple sclerosis A. Reynolds1, K.E. O’Connell1,2, T. Mok3, B. Sweeney3, A.M. Ryan3, K.K. Dev1 1
Drug Development, School of Medicine, Trinity College Dublin, Ireland, 2Institute of Psychiatry, Kings College London, UK, 3 Department of Neurology, National Neuroscience Centre, Cork University Hospital, Cork, Ireland Presenting Author: Audrey Reynolds: [email protected]
P5.4. S1P receptor activation attenuates psychosineinduced demyelination and astrocyte dysfunction C O’Sullivan, K.K. Dev Drug Development, School of Medicine, Trinity College Dublin, Ireland Presenting Author: Catherine O’Sullivan [email protected]
Krabbe disease is a rare autosomal recessive neurodegenerative disorder affecting 1:100,000 births. This illness is rapidly progressing, appearing within the first three to 6 months of life and is usually fatal by the age of 2 years. Krabbe disease is caused by a deficiency in the lysosomal enzyme galactocerebrosidase (GALC), which results in the accumulation of a toxic metabolite in the brain termed psychosine. The build-up of psychosine is believed to be the main pathogenic agent in Krabbe disease resulting in widespread oligiodendrocyte cell death and demyelination. To date, most studies have focused on the toxic effects of psychosine on oligiodendrocytes, however little is known about the effects of psychosine on astrocytes. Astrocytes, the most abundant cell type in the brain, have many important functions such as protection and support of neurons and oligodendrocytes. Astrocytes also play key roles in regulating metabolic and ion homeostasis in the CNS. Importantly, astrocytes express S1P receptors (S1PR) which are targets for the first oral therapy developed for multiple sclerosis, FTY720 (Fingolimod). S1PRs have various roles in the CNS, including astrocyte migration, oligodendrocyte survival, and neurogenesis. More recently, S1PRs have been found to play a role in inhibiting the release of pro-inflammatory cytokines from glial cells. Here we investigate the effect psychosine has on human and rat astrocyte survival and on the release of pro-inflammatory cytokines from mouse astrocytes. In addition we investigate the effect psychosine has on the myelination state of mouse cerebellar slices. Importantly we demonstrate the protective effects the phosphorylated version of FTY720 (pFTY720) has against both the psychosine induced cell-toxicity and the psychosine induced demyelination of cerebellar slices. In brief, we find psychosine induces astrocyte cell death in a concentration- and time-dependent manner and pre-treatment with pFTY720 attenuates this psychosine induced cell death and significantly prolongs astrocyte cell survival. In addition, psychosine potentiates the LPS-induced production of proinflammatory cytokines. Notably, treatment with pFTY720 attenuates the release of these pro-inflammatory cytokines. Importantly, pFT720 treatment also inhibits the psychosine induced demyelination of cerebellar slices. Taken together, these results suggest that S1PRs could be potential drug targets for Krabbe disease. Acknowledments: This work was supported in part by research grants from Trinity College Dublin, The Health Research Board Ireland, Science Foundation Ireland and The Higher Education Authority Ireland (Programme for Research in Third Level Institutions [PRTLI]). COS is a PRTLI funded PhD Scholar.
Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease that is one of the leading causes of disability in young adults. It affects nearly 1 in 1,000 people in Europe. Neuromyelitis optica, traditionally thought to be a variant of MS, was recently discovered to be caused by an antibody against aquaporin-4 (AQP4), a membrane protein that conduits water through the astrocyte cell membrane. Recent MS research has also identified autoantibodies for an inward rectifying potassium channel (KIR4.1) found on astrocytes in the sera of a number of MS patients, though other studies have indicated that this may be an epiphenomenon due to the presence of KIR4.1 in gastric parietal cells and the common occurrence of anti-parietal cell antibodies in MS patients with gastric disturbance. Nonetheless these findings have raised interest in the possibility of astrocytic autoantibodies in MS. The current study aimed to identify astrocytic autoantibodies in the cerebrospinal fluid (CSF) of patients with MS. Human astrocytes were grown and indirect immunofluoresence was used to determine the presence of antibodies. Astrocytic autoantibodies were detected in 40.9 % of the MS CSF samples and in none of the control CSF samples. These figures are similar to the number of KIR4.1 autoantibodies found in MS patients and indicate that CSF could be a valuable area to explore for the presence of autoantibodies. This new research into astrocytopathy in MS could shift the paradigm of research into the disease.
P5.6. Investigating the relationship between astrocytes, the immune system, and antipsychotics in schizophrenia L. Kennedy1, K.E. O’Connell1,2,3, J. Thakore3, K.K. Dev1 1 Drug Development, School of Medicine, Trinity College Dublin, Ireland, 2Institute of Psychiatry, Kings College London, UK, 3 Neuroscience Centre, St. Vincent’s Hospital Fairview, Fairview, Dublin, Ireland
Presenting Author: Liam Kennedy [email protected]
Schizophrenia is a severe, chronic, debilitating mental illness characterised by hallucination, delusion, thought disorder and negative symptoms. Despite affecting nearly 1 % of the general population, the aetiology of the condition remains unclear: hypotheses implicating dopamine, glutamate, serotonin, neurodevelopment and neuroimmune interactions have all been proposed. Accumulating evidence indicates a major role for neuroinflammation and psychoneuroimmunology in the pathophysiology of schizophrenia. Previous studies have detected circulating autoantibodies against astrocyte muscarinic acetylcholinergic receptors in schizophrenic patients’ serum. The recent discovery of NMDAR autoantibodies causing an organic psychosis has contributed to renewed interest in the field of autoimmunity in schizophrenia. This study set out to investigate the presence of circulating autoantibodies against astrocytes in the serum of clozapine-treated schizophrenic patients. Blood samples were collected from patients attending an urban mental health clinic with a diagnosis
S10 of schizophrenia. Age-matched healthy controls were recruited using posters and flyers in the surrounding mental health clinics and hospital. A cell-based indirect immunofluorescence assay was used to determine the presence of autoantibody. Human astrocyte cultures were incubated in 1:10 serum dilution, and subsequently in Alexa Fluor 488 goat anti-human fluorescent antibody. No significant staining was detected in schizophrenic (n = 20) or healthy control (n = 20) groups. Faint staining was quantified as arbitrary units of fluorescence using ImageJ software, revealing a non- significant trend toward higher levels of fluorescence in the schizophrenia group. Future studies may obtain more conclusive results from a larger sample size, as reported seroprevalence of autoantibodies in schizophrenia in previous studies lie at approximately 5 %.
P5.7. EBI2 regulates myelin development and inhibits lpc-induced demyelination Aleksandra Rutkowska1, Andreas W. Sailer2 and Kumlesh K. Dev1 1 Drug Development, School of Medicine, Trinity College, Dublin, Ireland. 2Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
Presenting Author: Aleksandra Rutkowska [email protected]
The G protein-coupled receptor EBI2 (Epstein-Barr virus-induced gene 2) is activated by 7, 25-dihydroxycholesterol (725HC) and plays a role in T cell-dependant antibody response and B cell migration. Aberrant EBI2 signalling is implicated in a range of autoimmune disorders however its role in the CNS remains poorly understood. Here we characterize the role of EBI2 in myelination under normal and pathophysiological conditions using organotypic cerebellar slice cultures and EBI2 knock-out animals. We find that MBP expression in brains taken from EBI2 KO mice is delayed compared to those taken from WT mice. In agreement with these in vivo findings, we show that antagonism of EBI2 reduces MBP expression in vitro. Importantly, we demonstrate that EBI2 activation attenuates lysolecithin-induced demyelination in mouse organotypic slice cultures. Moreover, EBI2 activation also inhibits lysolecithin-mediated release of pro-inflammatory cytokines such as IL6 and IL1 in cerebellar slices. These results, for the first time, display a role for EBI2 in myelin development and protection from demyelination under pathophysiological conditions and suggest that modulation of this receptor may be beneficial in neuroinflammatory and demyelinating disorders. Acknowledgments: The authors are grateful to Dr. Inga Preuss for experimental support. This work was supported by Irish Research Council (IRC) - Enterprise Partnership Scheme (EPS) with Novartis Pharma, Basel, Switzerland. AR is a IRC-EPS funded PhD Scholar.
P5.8. Neuropathological analysis of human postmortem multiple sclerosis brain tissue Siew-Mei Yap, Richard Magee, Yvonne. M. Nolan and Eric J. Downer Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland Presenting Author: Siew-Mei Yap [email protected]
Analysis of post-mortem brain tissue allows for characterisation of lesion pathology in the various subsets of patients with Multiple Sclerosis (MS). We performed a systematic analysis of
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 neuropathological autopsy reports of 13 patients with Primary Progressive MS (PPMS) and 11 patients with Secondary Progressive MS (SPMS), as well as 8 non-MS control subjects. These reports were based on brain and spinal cord tissue samples provided by the UK Multiple Sclerosis Tissue Bank. All tissues have been collected following informed consent by the donors via a prospective donor scheme according to Ethics committee approval. Interestingly, evidence of remyelination in the form of shadow plaques (areas of gliosis detected by Holzer staining) and diffuse myelin pallor was seen in 38 % of patients with PPMS (n = 5) but only one patient with SPMS. Furthermore, the brain load of these remyelination plaques is extensive in these patients with PPMS, but only one shadow plaque was detected in the brain tissue of the individual patient with SPMS. This finding of extensive remyelination in patients with PPMS has been described the literature. In addition, the average brain weight of patients with PPMS is 14 % greater than that of patients with SPMS (1263 g vs 1088 g). The overwhelming cause of death in all patients with MS was bronchopneumonia (n = 14, 58 %). Variability was observed in the first presenting symptom (visual, sensory, motor, cerebellar/brainstem, bladder dysfunction) with no standout symptom in terms of frequency. Neuropathological analysis was also performed on cortical cryosections (8 lm) from PPMS, SPMS and non-MS control samples. Normal-appearing white matter (NAWM) and chronic active white matter lesions were characterised using Luxol Fast Blue and hematoxylin staining. We provide evidence of marked demyelination in the cortex associated with active lesions in PPMS and SPMS samples, compared to the control NAWM specimens. The above preliminary findings provide a basis on which to continue research into factors contributing to demyelination and remyelination in MS. Furthermore, future investigation will delineate the pathophysiology and variable natural history of the disease. Acknowledgment: Tissue samples were supplied by the Multiple Sclerosis Society Tissue Bank, funded by the Multiple Sclerosis Society of Great Britain and Northern Ireland, registered charity 207495.
P5.9. sleep-wake modulation of the induction and expression of long-term potentiation in the rat hippocampal CA1 area in vivo Chandra R, Rowan MJ Department of Pharmacology and Therapeutics, and Institute of Neuroscience, Trinity College, Dublin 2, Ireland Presenting Author: Ruchi Chandra [email protected]
Long-term potentiation (LTP), an activity- dependent longlasting enhancement of synaptic transmission, is modulated by animals behavioural state in the dentate gyrus and stratum oriens of the hippocampus. Here we study the induction and expression of LTP at CA3-to- CA1 synapses in the stratum radiatum during different behavioural state. Experiments were performed on adult male Wistar rats (320–400 g). Chronic stimulation and recording wire electrodes were implanted under xylazine and ketamine (8 and 80 mg/kg, i.p) anaesthesia. Rats were entrained to a 24 h light:dark cycle (L:D 8 p.m.:8 a.m.). Recordings were performed during the day hour from 11–3 p.m. Electrically evoked field excitatory postsynaptic potentials were measured in the dorsal hippocampus. The high-frequency stimulation (HFS) protocol for inducing LTP consisted of 10 trains of 20 stimuli with an interstimulus interval of 5 ms (200 Hz) and an intertrain interval of 2 s. The ability to induce LTP varied significantly depending on the animals behavioural state. Application of HFS during REM sleep or while the rat was in a still alert state
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 induced significant LTP (p0.05 compared with pre-HFS baseline, n = 10). However the application of same HFS protocol failed to induce significant overall LTP when the animal was either moving or in NREM sleep (p0.05, n = 10). Moreover the expression level of LTP, once induced, varied depending on the behavioural state, with evidence of enhanced LTP expression during REM sleep compared with NREM sleep when HFS was applied during either REM sleep or when the animal was moving (p0.05). In conclusion, behavioural state can strongly influence both the induction and expression of LTP.
P5.10. Regulatory T cells promote cns myelin regeneration in vivo Yvonne Dombrowski1, Peter Bankhead1, Rebecca J. Ingram1, Chao Zhao2, Robin JM Franklin2, Denise C. Fitzgerald1 1
Queens University Belfast, UK 2University of Cambridge, UK
Presenting Author: Y. Dombrowski [email protected]
Remyelination is a crucial regenerative process in Multiple Sclerosis; however, it often fails in chronic disease progression. There is no therapy for myelin regeneration to date a demand that needs to be addressed. Despite their pathological role in autoimmune-mediated demyelination, T cells have been identified as potential regulators of CNS remyelination. This study aimed to identify the role of regulatory T cells (Tregs) in myelin repair using transgenic FoxP3-DTR mice in which Tregs were specifically depleted by diphtheria toxin administration. Focal demyelinated lesions were induced in these mice by injection of lysolecithin into the spinal cord. Treg cell depletion reduced mature myelin-producing oligodendrocytes in remyelinating lesions in vivo. This indicates that Treg depleted mice have a defect in their myelin repair capacity. Furthermore, in brain cell cultures and in an ex vivo brain slice model, supernatant generated from Treg cultures promoted myelin production by oligodendrocytes and myelination of neurons, respectively. These data suggest a novel beneficial role of Tregs in remyelination. Recently, Tregs have been identified as novel regulators of muscle regeneration by modulating a shift from a M1 to M2 macrophage phenotype, thereby promoting tissue repair. A similar mechanism in myelin repair may be possible, however, our preliminary data suggest an additional direct mechanism beyond the immunomodulating capacity of Tregs. The underlying mechanisms are currently under investigation.
P5.11. Identification of inflammasome expression and activity in experimental autoimmune encephalomyelitis (EAE) Samara Fleville, Marie Dittmer, John Falconer, Pete Bankhead, Ingrid Allen, Denise C. Fitzgerald*, Yvonne Dombrowski* Centre for Infection and Immunity, Queens University Belfast *Indicates joint senior authors Presenting Author: Samara Fleville [email protected]
Background EAE is an immune-mediated animal model of Multiple Sclerosis (MS). In this model, mice have multiple demyelinated lesions distributed throughout the central nervous system (CNS). Inflammasomes are intracellular, innate immune complexes known to have a pathogenic role in EAE development. In EAE inflammasomes are activated by danger-associated molecular patterns to mature and
S11 release pro-inflammatory cytokines, IL-1B and IL-18. Objectives To identify inflammasome activity in different CNS cells of the spinal cord; we aimed to establish immunofluorescent staining of inflammasome components. To assess the effect of IL-1B on oligodendrocytes. Methods To establish immunohistochemistry protocols, spinal cord sections from EAE mice were stained for inflammasome components AIM2, ASC and IL-1B. To test the effect of IL-1B on oligodendrocytes, oligodendrocyte lineage cells were derived from frontal cortices of postnatal mice and treated with IL1B. Cultures were stained for oligodendrocyte lineage and myelin markers. Results We established immunofluorescent staining for AIM2, ASC and IL-1B, and thus identified inflammasome activity in demyelinated spinal cord lesions. In vitro, exogenous IL-1B significantly enhanced myelin protein production from oligodendrocytes. IL-1B did not increase the number of mature oligodendrocytes. Conclusions AIM2, ASC and IL-1B immunohistochemistry demonstrated inflammasome activity in demyelinated spinal cord lesions. Future studies will develop co-staining for CNS markers to determine which cells express inflammasomes in EAE-induced lesions. Our studies show that IL-1B drives oligodendrocyte maturation and myelin protein production in glial cultures. Future work will assess the effect of the inflammasome product IL-18 on oligodendrocyte cells.
P5.12. Influence of regulatory T cells on oligodendrocyte lineage cells in vitro Marie Dittmer1, Thomas O’Hagan1, Peter Bankhead3, Reinhold Medina2, Yvonne Dombrowski1, Denise C. Fitzgerald1 1
Centre for Infection and Immunity, Queens University Belfast, Northern Ireland, UK; 2Centre for Experimental Medicine, Queens University Belfast, Northern Ireland, UK; 3Centre for Cancer Research and Cell Biology, Queens University Belfast, Northern Ireland, UK Presenting Author: Marie Dittmer [email protected]
The process of myelin regeneration (remyelination) in the central nervous system (CNS) is still not understood in its entirety. Uncovering the mechanisms that govern remyelination will benefit patients with demyelinating diseases such as multiple sclerosis. Oligodendrocytes and oligodendrocyte precursor cells (OPCs) are the myelinating cells of the CNS and therefore play a central role in remyelination. It has been shown that cells of the adaptive immune system, particularly CD4? T cells, promote remyelination in vivo. Based on our observations that regulatory T cell (Treg) depletion impairs remyelination in vivo, we hypothesized that Tregs enhance remyelination through support of oligodendrocyte lineage cells. To test this hypothesis, Tregs were first differentiated in vitro and supernatants from these cultures were harvested. The effect of Treg-conditioned media on OPC maturation, proliferation and survival were investigated in an in vitro model of murine mixed glial cells. Treg-conditioned media significantly enhanced OPC maturation, while there was no effect on OPC proliferation or survival. Furthermore, we could identify Treg-derived Protein Of Interest (POI) facilitating the enhancement of OPC maturation. Recently, it was shown that Treg have an intrinsic repair function in muscle regeneration through immune modulation and effects on satellite cells. A similar intrinsic function in myelin regeneration by driving OPC maturation is therefore likely. Our studies suggest a novel beneficial role of Treg in remyelination distinct from immune modulation through the enhancement of OPC maturation via Tregderived POI.
P5.13. YB T cells; a novel T cell subset with a pathogenic role in il-17-mediated cns autoimmunity Edwards SC, Sutton CE, Mills KHG
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 may play a role in promoting Th17 cell development, possibly by promoting innate IL-1 and IL-23 production. Our findings suggest that IL-17A may function not simply as an effector cytokine that promotes chemokine production and neutrophil recruitment in host defence, but as a pathogenic cytokine in autoimmunity through the induction or the expansion of Th17 cells.
School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland Presenting Author: Sarah Edwards [email protected]
Vy4? T cells have been identified as the main IL-17-producing yd T cell in the CNS of mice with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. This study demonstrates that Vy4? T cells are present in T cell receptor (TCR)d-/- mice, and these Vy4? T cells co-express TCRb. The data reveals that Vy4b T cells respond to IL-1b and IL-23 stimulation in the absence of TCR engagement to produce IL-17 and express the master transcription factor, RORyt. Furthermore, Vy4b? T cells were found in the brains of TCRd-/- mice, and together with Vy4d? T cells in the brains of wild type (WT) mice with EAE. Although, the course of EAE is somewhat reduced in TCRd-/- compared with WT mice, depletion of Vy4? T cells from TCRd-/- and WT mice significantly attenuated clinical disease and weight loss in mice with EAE. Anti-Vy4 treated mice with EAE had a significantly reduced frequency of infiltrating IL-17?, IFN-y? and IFN-y? IL-17?CD4? T cells into CNS. Furthermore, in the adoptive transfer model of EAE, depletion of Vy4? cells from lymph node and spleen cells from TCRd-/- mice significantly impair their ability to induce EAE, with a reduction in inflammatory T cells infiltrating the CNS. Our study has identified a novel yb T cell subset, Vy4b T cells, which together with conventional Vy4d T cells, play a critical role in the pathogenesis of EAE through innate IL-17 production, enhancing Th17 and Th1 activation and migration into the CNS to mediate inflammation and autoimmunity.
P5.14. The mechanism of pathogenicity of IL-17A in CNS autoimmunity Aoife McGinley, Kingston HG Mills School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland Presenting Author: Aoife McGinley [email protected]
IL-17 and IL-17-producing CD4 T cells (Th17 cells) and gamma delta T cells are emerging as central players in the pathogenesis of many autoimmune diseases. MS is a demyelinating inflammatory disorder of the CNS, involving autoreactive T cell responses to myelin antigens. In this study we have used a murine model of MS, EAE, to examine the role of IL-17A in the development of CNS inflammation. We found that IL-17A-/-mice are largely resistant to EAE induced by immunization with MOG and CFA. Consistent with this, when compared to WT controls, there were significantly lower numbers of CD4 and T cells secreting GM-CSF, IFNgamma or IL-17F in the spleens and lymph nodes of IL-17-/- mice prior to EAE symptom onset, and in the CNS following symptom onset. Furthermore, WT mice treated with a neutralizing anti-IL-17A antibody throughout the course of disease or only at EAE induction showed a similar attenuation of EAE. Surprisingly, T cells from MOG-immunized IL17A-/- mice were capable of inducing disease following transfer into WT mice, demonstrating that IL-17A-production by T cells is not essential for EAE induction. Finally, we have evidence that IL-17A
P5.15. Amyotrophic lateral sclerosis patient fibroblasts are a useful tool to model impaired autophagy Martin Madill, Sanbing Shen Regenerative Medicine Institute, National University of Ireland, Galway Presenting Author: Martin Madill [email protected]
ALS is a neurodegenerative disease characterized by progressive loss of both upper and lower motor neurons, with death usually occurring within 3-5 years of diagnosis. It is a multi-factorial disease with many genetic and environmental factors implicated in its development. Currently only one FDA approved therapeutic is available, Riluzole, which exerts limited efficacy. Autophagy is a process by which cells maintain a balance between nutrient supply and cell growth, recycling long lived and misfolded proteins. Several studies have indicated that impaired autophagy may be implicated in the pathogenesis of this disease. Further, many of the major ALS-related proteins are prone to misfolding, including SOD1, TDP-43 and FUS. It has been suggested that activation of autophagy may be therapeutically beneficial. However, other studies have suggested the opposite. Herein we suggest that ALS patient fibroblasts may be a useful model to study the mechanisms of impaired autophagy as they can represent a wide variety of genetic mutations, as well as sporadic ALS cases. Our primary findings indicate that fibroblasts can recapitulate the defects in the autophagy pathway reported in animal models. Further, we assess the effect of inducing autophagy via Rapamycin and hypoxia.
P5.16. Ferrocene perturbs iron metabolism in organotypic hippocampal slices Sinead Healy, Jill McMahon and Una FitzGerald Galway Neuroscience Centre, Biosciences, National University of Ireland Galway, Ireland Presenting Author: Sinead Healy [email protected]
Introduction:Iron may contribute to the pathogenesis and progression of multiple sclerosis. Recent studies have shown alterations in iron distribution and the expression of iron-related molecules [1,2]. A clearer picture of this metabolic dyshomeostasis of iron might be described using an ex vivo slice culture platform. In the present study, we used 3 different iron treatments of organotypic cultures of hippocampal slices to study molecules involved in aberrant iron homeostasis. Methods:Hippocampal slices derived from postnatal P10/P11 rats were cultured for 10 days before exposure to 10uM ferrous ammonium sulfate, ferric citrate or ferrocene. Iron levels were quantified using a ferrozine colorimetric assay and viability was assessed using LDH and MTT assays. Using real-time PCR, expression levels of iron-storage molecule ferritin light chain were determined. Results:Firstly, these slice cultures demonstrated normal iron content (5.61 ± 0.66 nmol/mg) after 10 days in culture compared with age-matched tissue and values reported for postnatal
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 primary cultures of CNS cells. Secondly, we demonstrated differential iron uptake and toxicity of iron after 12 h exposure to 10uM ferrous ammonium sulfate, ferric citrate or ferrocene i.e. a supraphysiological iron concentration. Thirdly, 1uM ferrocene produced a maximal 1.6fold increase in iron content (from 4.97 ± 0.57 to 8.05 ± 0.98 nmol/ mg) that is comparable with total iron increase detected in postmortem brain during neurodegenerative disease. This iron accumulation was confirmed by detection of transcriptional upregulation of ferritin light-chain (an iron storage protein). Conclusion:Ferrocene loading perturbs iron metabolism in our ex vivo organotypic hippocampal slice culture system. This model of iron loading appears to be a promising platform for studying iron regulation in the CNS.
P5.17. Immune stimulatory nucleic acids differentially regulate the expression of HO-1 in astrocytes, microglia and peripheral macrophages Glyn Williams, Donal Cox and Aisling Dunne School of Biochemistry & Immunology and School of Medicine, Trinity College Dublin Presenting Author: Glyn Williams [email protected]
The heme oxygenase (HO) system catalyses the conversion of free heme to the linear tetrapyrroles biliverdin (BV) and bilirubin (BR) with the concomitant release of free iron and carbon monoxide. As well as being involved in normal red blood cell turnover, the HO system is strongly induced under conditions of cellular stress and inflammation and several studies have reported that heme breakdown products have potent anti-inflammatory/antioxidant activities. Furthermore, induction of the inducible form of HO (HO-1) following administration of cobalt protoporphyrin (CoPP) has been shown to alleviate symptoms of animal models of colitis, arthritis and multiple sclerosis. Little is known regarding the regulation of HO-1 in cells of the CNS during infection. We have assessed the expression of HO-1 in astrocytes and microglia following stimulation with viral immune stimulatory nucleic acids (ISNAs) and found that expression of this stress response protein is differentially regulated in the two cell types. ISNAs induced robust expression of HO-1 in astrocytes whereas microglia displayed higher basal levels of the enzyme and this was reduced following exposure to viral DNA/RNA mimetics. ISNAs drive the production of the anti-viral cytokine, IFN. Treatment of microglia with this cytokine also reduced HO-1 expression while gene silencing of key ISNA receptors led to enhanced basal level of HO-1. A similar profile was seen with bone marrow derived macrophages suggesting that HO expression is regulated by interferon and the protective properties of this enzyme may be lost in microglia and macrophages during viral infection.
P5.18. An investigation into baclofen as a modulator of central TLR3/TLR4 signalling Tadhg Crowley1, John-Mark Fitzpatrick1, Orna O’Toole3, John F. Cryan1,2, Olivia F. O’Leary1,2,Eric J. Downer1 1 Department of Anatomy and Neuroscience, University College Cork, Ireland; 2 Alimentary Pharmabiotic Centre, University College Cork, Ireland; 3 Mercy University Hospital, Cork, Ireland
Presenting Author: Tadhg Crowley [email protected]
S13 Baclofen, a GABAB receptor agonist, is a common treatment for spasticity, associated pain and disability in Multiple Sclerosis (MS). Inflammation is a key driver of central pathology in MS and is mediated by both immunoreactive glial cells and invading lymphocytes. Innate immunity in the form of Toll-like receptors (TLRs) and downstream effectors has received much interest in the progression of MS. Thus the aim of present study was to determine whether baclofen attenuates TLR3 and/or TLR4-induced inflammatory signalling in glial cells which play a key role in inflammation in the central nervous system. Mixed glial cultures were prepared from the brains of 1-day-old C57BL/6 mice. Cells were pretreated with baclofen (10, 30, 100 lM) followed by either LPS (100 ng/ml) or Poly(I:C) (10 lg/ml) to promote inflammatory signalling. Nuclear translocation of the NFB-p65 subunit was measured using fluorescence immunocytochemistry. Release of the proinflammatory cytokines TNF-, IL-6 in glial cells and measured by ELISA. TLR4 signalling was also assessed in peripheral blood mononuclear cells (PBMCs) isolated from newly diagnosed MS patients and healthy control individuals. LPS significantly increased nuclear translocation of NF-B-p65 and induced the release of TNF- and IL-6 in glial cells. This was not attenuated by the baclofen pretreatment. Poly(I:C)-induced a non-statistically significant increase in nuclear translocation of NF-B-p65 and release of TNF- and IL-6. Finally, our data indicate that LPS induces TLR4 signalling in PBMCs isolated from MS and control subjects. Overall these findings indicate that baclofen does not significantly attenuate TLR3/TLR4-induced release of proinflammatory cytokines in glial cells. Current studies are also investigating the effects of baclofen on TLR3 and TLR4-induced inflammatory signalling in PBMCs. Disclosure: Ethical approval for the study was granted from the Clinical Research Ethics committee of the Cork Teaching Hospitals (CREC). Written informed consent was obtained from each participant in the study. This work was supported by the Department of Anatomy and Neuroscience, UCC, and the Translational Research Access Programme (TRAP) (to EJD) (grant code: AS0702).
P5.19. Treatment of relapsing remitting multiple sclerosis with fingolimod: our experience at the department of neurology, Bon Secour Tralee Moira Hayes and Dr. Helena Moore Department of Neurology, Bons Secours Tralee Presenting Author: Moira Hayes. Multiple sclerosis (MS) is a chronic, idiopathic, and generally progressive inflammatory demyelinating disease of the central nervous system characterized by diverse deficits of nervous system function that remit and relapse, multiple loci of demyelination distributed throughout the brain and spinal cord, and scarring (sclerosis) of damaged myelin and associated nerve fibers. Fingolimod (GilenyaTM) is a recently-approved sphingosine 1-phosphate receptor modulator that significantly reduces relapse rate in patients with relapsing/ remitting MS (RRMS). Here we describe our experience with the first 30 patients treated for RRMS with fingolimod at Bons Secours Tralee. The mean (± SD) patient age when beginning fingolimod therapy was 42.4 ± 9.3 years (range 23–61) and mean disease duration was 8.2 ± 3.7 years (range 3–20); 65 % of these patients are female. Prior therapies included interferon beta-1a and 1b (n = 23), glatiramer acetate (n = 4), and natalizumab (n = 2). As of August 2014, the mean duration of ongoing fingolimod therapy was 17.6 ± 8.5 months and 2 patients had experienced relapses while receiving fingolimod— one occurring 2 months and one 12 months after beginning treatment. There have been 3 discontinuations to date, with one each due to raised
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liver enzymes, lymphopenia, and macular edema. One patient experienced an adverse event of second-degree atrioventricular block and sustained bradycardia following initial dosing with fingolimod. This patient was successfully treated by isoprenaline infusion and discharged. In summary, our experience in treating patients with RRMS with fingolimod has been generally consistent with results obtained previously in randomized, controlled clinical trials.
P5.20. Endoplasmic reticulum stress-associated proteins in saliva: potential biomarkers for multiple sclerosis? Jill McMahon1, Eibhlı´n Higgins1, Anthony Garvey Timothy Counihan2 & Una Fitzgerald1
Multiple Sclerosis Research Group, Galway Neuroscience Centre, Biosciences, National University of Ireland, Galway; 2 Department of Neurology, Galway University Hospitals Presenting Author: Jill McMahon. Biomarkers are quantitative measures that are essential in all areas of medicine for diagnosis, disease assessment and testing of drug efficacy. The established biomarkers for multiple sclerosis (MS), such as MRI scans and the presence of oligoclonal bands in cerebrospinal fluid, tend to under-estimate the degree of pathology present, and their expense and sometimes invasive nature means that repeated sampling can be limited. The endoplasmic reticulum (ER) is an adaptive organelle which can initiate a stress response as a result both of normal physiological and disease-associated pathogenic conditions. This signalling pathway is normally pro-survival but under prolonged periods of chronic cell stress it may lead of cell death. We have previously reported an increase in the expression of ER stress-associated molecules in demyelinating lesions, as well as in an EAE animal model of MS and also in serum samples from MS patients. We hypothesise that ER stress-associated molecules may be released from areas of pathology into the cerebrospinal fluid (CSF) and from there, via the subarachnoid space and cribiform plate, into the oral cavity to mix with saliva. To test this hypothesis we have been developing a simple dot-blot methodology to allow quantification of GRP78 (BiP), Calreticulin, ORP 150 and ERp44 in saliva. The cohort studied consists of MS patients, non-MS neurology patients and non-disease controls. There was large variation in values in all groups and statistical power was limited by small sample size but a trend towards increased levels of GRP78 in MS patients was seen. This is in agreement with data produced previously in our group when testing other cohorts and suggests that measurement of salivary GRP78 (BiP) could represent a cheap, non-invasive biomarker in MS.
P5.21. Molecular mechanisms underlying ALS linked toxicity in astrocytes Sinead O’Sullivan, Kumlesh K. Dev Drug Development, School of Medicine, Trinity College Dublin, IRELAND Presenting Author: Sinead O’Sullivan. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease which is characterised by the death of both the upper and lower
motor neurons. Most people diagnosed with ALS are aged between 40–50 years and have a life expectancy of 3–5 years after symptom onset. The gene encoding the superoxide dismutase 1 protein is one of the genes implicated in this disease. It is becoming more accepted that ALS is a non-cell autonomous disease and not just a disease of the motor neurons. It is now thought that astrocytes are central to the ALS disease process. Here, we examine how postnatal day 1 (P1) transgenic SOD1 G93A astrocytes respond to system challenges compared to wild type astrocytes. We report that P1 transgenic astrocytes are more resistant to Hydrogen peroxide (H2O2) induced toxicity than their matched wild type control. These results indicate that transgenic astrocytes have altered intracellular signalling cascades compared to wild type astrocytes and that the SOD1 enzyme may have a toxic gain of function in effected astrocytes. Lipopolysaccharide (LPS) was also shown to cause a significant increase in cytokines such as IL-6, TNFa, LIX and IL-1 from transgenic astrocytes compared to wild type. Such raised levels of cytokines could have detrimental effects on surrounding cells, such as neurons, which could lead to apoptosis. In addition, pERK and pAKT pathways were also show to be aberrant in transgenic astrocytes compared to wild type. As a result of the complexity of astrocytic activities, understanding these abnormal molecular biological processes may lead to advances in new therapies for ALS. Acknowledgements: This work was supported by research grants from the Health Research Board (HRB) Ireland. SOS is an HRB funded PhD Scholar. We acknowledge Prof. Jochen Prehn (RCSI) for support in this study.
P5.22. The role of the multiple sclerosis nurse specialist at Beaumont Hospital Valerie Williams Department of Neurology, Beaumont Hospital, Dublin, Ireland Presenting Author: Valerie Williams. Multiple sclerosis (MS) is a chronic, autoimmune inflammatory demyelinating disease of the central nervous system, with a variety of neurological symptoms. It affects over 2.5 million people worldwide and Ireland has been recognized as a high risk area for MS with a prevalence rate ranging between 120–180 per 100,000. Specialist nurses are being considered as fundamental to the care needs for patients. The objective at Beaumont hospital was to assess the role of the MS nurse specialist in patients with MS. The focus was on the wellness model with the aim to empower the person with MS to develop self-awareness and to take responsibility for their own health. The MS nurse specialist has always taken an active role in the MS clinical setting by providing advice, support and education for patients with MS and their families. At Beaumont hospital, among the 51 patients who started disease modifying therapies from January to July 2014, 30 received fingolimod. To ensure patients receive the best and safest care, the MS nurse specialist has developed the nurse led fingolimod preassessment clinic, with a maximum time in educating each patient of 2 h. At Beaumont hospital, the MS nurse specialists provide an invaluable service as members of the multidisciplinary team for patients with MS. They support and enable patients to live with their chronic condition, to meet their maximum potential in life. At all times, they aim to meet patients’ needs and strive to maintain a high standard of care.
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P5.23. Helminth-induced IL-5 and IL-33 protect against experimental autoimmune encephalomyelitis Conor M Finlay, Anna M Stefanska, Patrick T Walsh, Ed C Lavelle, Kingston HG Mills School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland Presenting Author: Conor M Finlay. Helminth parasites typically establish chronic infections in the mammalian host which can persist for decades. Helminths evade protective host immune responses by promoting innate and adaptive antiinflammatory networks which can also suppress immune responses to unrelated antigens. Indeed, it has been shown parasitic infection of humans is associated with a lower incidence of allergy and autoimmune disease in rural areas of the developing world. Experimental models of autoimmunity have revealed that helminth-induced protection against disease can be mediated by the action of either Treg or Th2 cells1. Here we examined the immunoregulatory effects of the excretory-secretory (ES) products of the helminth parasite, Fasciola hepatica, in the mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Administration of ES delayed the onset and attenuated the clinical severity of EAE which was associated with a decreased production of auto antigen-specific IFN-c and IL-17. Unexpectedly, IL-10, TGF-b, or regulatory T cells did not play a role in the ES-induced attenuation of disease. Moreover, ESelicited T cells did not suppress EAE and protection from disease was also retained in IL-4-deficient mice, suggesting that Th2 cells do not play a role in ES-induced amelioration of EAE. However adoptive transfer of macrophages or eosinophils, from ES-treated mice transferred protection. Furthermore, IL-5, a cytokine which mediates eosinophilia in vivo, was required for ES-induced protection against EAE. Moreover, we have shown that the type-2 alarmin and IL-1 family member cytokine, IL-33 was induced following administration of ES to animals and was indispensible for eosinophilia. Finally we confirmed that ES-mediated protection against EAE was IL-33 dependent as IL-33-deficient animals were not protected from the disease. These findings provide novel insights into how helminths modulate the immune response in autoimmunity and identify IL-33 and IL-5 as endogenous molecules with potential therapeutic activity. Reference 1. Finlay, C.M., Walsh, K.P., and Mills, K.H.G. (2014b). Induction of regulatory cells by helminth parasites: exploitation for the treatment of inflammatory diseases. Immunological Reviews 259, 206-230.
P5.24. Rett syndrome and IGF-1 therapy Michael Ryan, Daniela Tropea Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin 2, Ireland Presenting Author: Michael Ryan Rett Syndrome (RTT) is an X-linked neurodevelopmental disorder that is a leading cause of severe intellectual disability in females. The disorder primarily arises from mutations in the gene that codes for methylCpG-binding protein 2 (MeCP2). At present, no specific treatment for RTT is available and management is largely symptomatic. Mouse models and early human trials suggest that insulin-like growth factor 1 (IGF-1) and its N-terminal tripeptide, glycine-proline-glutamate (GPE), may improve clinical features of RTT. Here, video recordings were utilised to investigate the effects of 24-weeks of IGF-1 therapy
S15 (0.05–0.1 mg/kg twice daily) on motor disability in 6 girls with RTT. Motor analysis was conducted using a novel, video-based instrument designed specifically to measure motor features of RTT. In addition, primary neuronal cultures were treated with IGF-1 or GPE and changes in neuronal morphology analysed. It was found that IGF-1 treatment significantly improved motor features of RTT across a diverse range of parameters. Moreover, IGF-1 and GPE treatments produced increases in primary neurite length and levels of MAP2, indicating enhanced neurite extension in primary neuronal cultures. These results provide support for IGF-1 as a potential pharmacological intervention in RTT and suggest that some of its clinical benefits may be the result of direct effects on neuronal morphology. However, the underlying mechanism of action of IGF-1 in RTT appears to be complex and further research is warranted to elucidate the effects of IGF-1 at the cellular and molecular level.
6 Posters Hot Topic: The role of Glial Cells in Neurological and Psychiatric Diseases P6.1. The role of glial cells in metachromatic leukodystrophy Christine Gaffney M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Christine Gaffney [email protected]
Metachromatic leukodystrophy (MLD) is a fatal lysosomal storage disorder caused by deficiency or deficient activity of the sulfolipid digesting enzyme arylsulfatase A, and the subsequent accumulation of sulfatides in the peripheral and central nervous system. The disease is characterised by progressive demyelination resulting in a wide range of neurological symptoms, culminating in decerebration and early death. Although neurons are directly affected by this neurodegenerative disorder, glial cells are also implicated in the disease progression. Astrocytes, microglia and oligodendrocytes all play key roles in maintaining a healthy CNS, and here it is hypothesised what function they may have in MLD. It was proposed that astrocytes may undergo reactive astrogliosis following CNS disease in this disorder, and this reaction may directly impact neuronal and glial function, ultimately triggering a vicious cycle of neuronal and glial death. Similarly, while microglia may initially play a neuroprotective role in MLD by promoting neural survival through the production of neurotrophic and anti-inflammatory factors, the neurotoxic effectors released by activated microglia in response to CNS insult could cause further damage to neurons, and it was hypothesised that this microglial activation would eventually exacerbate the condition. Additionally, oligodendrocyte function is directly affected by MLD, as sulfatide accumulates in the lysosomes of oligodendrocytes and is thought to kill them, and this may contribute to the severe demyelination apparent in this disease. Overall it is clear that glial cells are not to be overlooked in examining the mechanisms of MLD, and further research may impact treatment options for this disorder.
P6.2. The role of glial cells in schizophrenia Sinead Rooney M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland
S16 Presenting Author: Sinead Rooney [email protected]
The neglect of neuroglia research, in favour of a focus on the neuron, has oversimplified our understanding of healthy and diseased states of the human brain. Today, the full purpose of glia is still unknown but there has been progress over the last 20 years as scientific views of these glial cells have slowly changed from being merely brain glue to multifunctional and active participants in brain function. Schizophrenia is a heritable and heterogeneous psychiatric disorder involving multiple symptoms such as generalized cognitive deficit, psychosis and depression; and its causes are still poorly understood due to its aetiological complexity. Concerted actions of various susceptibility genes (e.g.: DISC1; Disrupted-in-Schizophrenia-1) and multiple environmental factor interactions (e.g.: maternal immune activation) play a major role in the manifestation of this debilitating illness which may be glial-facilitated via: (1) impaired astrocyte function in the blood brain barrier and glutamate homeostasis (2) enhanced pro-inflammatory cytokine release by primed microglia, and (3) abnormal myelination due to arrested maturation and apoptosis of oligodendrocytes. The mechanisms of action of antipsychotic medications may reduce astrocytic glutamate-transporter EEAT2 activity (improving hypoglutamatergia), producing immunosuppressive effects by inhibiting microglial release of TNF- and nitric oxide, and promoting oligodendrocyte growth and expression of transcription factors OLIG1/OLIG2. The ongoing investigation of glial involvement in the development and maintenance of Schizophrenia has opened new avenues toward a more complete understanding of its aetiology and generation of more effective treatments targeting glial function in the future. Here, the role of glial cells in Schizophrenia will be reviewed.
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18 oxygen species and a sequential failure to detoxify, leading to a proinflammatory phenotype, typical of those seen in the various subtypes of Batten Disease.
P6.4. Role of glial cells in krabbes disease Keagan Dunville M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Keagan Dunville [email protected]
Krabbes disease, or globoid cell leukodystrophy, is an autosomal neurodegenerative disease which manifests in early juveniles. Excess psychosine, a myelin sphingolipid metabolite, accumulates in Krabbes-afflicted neural tissue as a result of dysfunctional galactosylceramidase, an enzyme responsible for degrading psychosines precursor. Krabbes disease characteristically shows demyelinated neurons and as a result adversely affects glial cells through oligodendrocyte inflammation and apoptosis, prolonged astrocyte inflammation, and reactive-state microglia. Glial cell mediated inflammation is constitutive in Krabbes and impairs reparative glial functions thereby propagating and augmenting the disease pathology. Krabbes disease is minimally treatable, incurable, and ultimately fatal for afflicted children younger than 2 years. The disease thus garners a high, unmet medical need and may be alleviated via glial targeting. Here the role of glia cells in Krabbes disease as cellular drug targets is presented.
P6.3. Glial involvement in the pathophysiology of batten disease P6.5. The role of glial cells in Tay-Sachs disease Aoife Burke Charlotte Rispin M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Aoife Burke [email protected]
The neuronal ceroid lipofuscinoses (NCL’s) or Batten disease, represent a group of neurodegenerative diseases, mostly present in childhood characterized by a diffuse accumulation of lipofuscin and ceroid in neuronal and non-neuronal tissues. The disease results in vision loss, mental retardation, progressive loss of motor function and chronic seizures with death usually occurring in the second or third decade of life. Currently, there are 14 variants of the disease, CLN1 to CLN14. The role of glial cells was reviewed in the juvenile form of the disease, Juvenile Neuronal Ceroid Lipofuscinosis, which is caused by a mutation in the CLN3 gene. Mounting evidence has suggested that reduced astrocyte activity is detrimental to neuronal viability in JNCL. This decrease in astrocyte function results in an increase in pro-inflammatory cytokines including TNFa and INFc, leading to neuro-inflammation exacerbating the disease progression. Impairments in astrocyte homeostatic effects, primarily hemi-channel over-activation, can compromise neuronal function and impact neuronal viability. In addition, areas of heightened microglial activation also predict regions that will undergo neurodegeneration in Batten disease. When chronically perturbed, microglia produce a vast range of pro-inflammatory cytokines, free radicals and chemokines responsible for progression of neural degeneration and atrophy in the brain. Less is known of the role of oligodendrocytes in JNCL. However, defects in oligodendrocytes can lead to excessive reactive
M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Charlotte Rispin [email protected]
Tay-Sachs disease (TSD) is a lysosomal storage disease caused by a mutation in the HEXA gene, encoding the enzyme N-acetylhexosaminidase A. The role of this enzyme is crucial as it provides the only breakdown pathway for GM2 gangliosides. The loss of function of this enzyme results in the accumulation of GM2. This accumulation is the main accepted pathway for neuronal apoptosis and neurodegeneration in the disease. Despite the lack of understanding of the role of glial cells in TSD, studies suggest that astrocytes, microglia and oligodendrocytes are affected by GM2 accumulation. Studies have shown that genes associated with astrocyte and microglial activation are highly elevated in TSD. Microglial activation has actually been shown to precipitate neuronal apoptosis and thus cause a cycle of inflammation and excitotoxicity. Furthermore, it may also interfere with oligodendrocytes causing hypomyelination. Microglial cells may also be linked with potential routes of treatment in the disease. The role of glial cells in TSD is still misunderstood however and research to date has lacked in focus towards the disease. A more focused route of research into the roles of glial cells the disease would not only be beneficial in elucidating the mechanistic pathways of the disease but also in marking glial cells as potential therapeutic targets for the disease. Here, the role of glial cells in TSD will be presented.
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
P6.6. The role of glial cells in huntington’s disease Adam Dyer M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Adam Dyer [email protected]
Huntington’s Disease (HD) is a progresive neurodegenerative disorder most frequently diagnosed in the fourth decade of life. HD is a monogenic disease with the mutation resulting in a mutant form of huntingtin protein (mHTT). Protein misfolding and aggregation results in degeneration of striatial medium spiny neurons (GABAergic). Research in HD has traditionally focussed on the degeneration of these neurons in the striatum. However, research into non-neuronal glial cells in HD is regarded as increasingly important. Glial cells are altered in number and function in HD brains and in transgenic/pharmacological murine models of HD. A consistent finding is an increased number of microglia and oligodendrocytes in HD. Microglia are functionally and morphologically altered, and the increased oligodendrocyte number occurs on a background of demyelination. Astrocyte-specific inflammatory markers and microglial cytokine/inflammatory mediator release are up-regulated in HD, contributing to neuroinflammation. The cellular picture of HD in cells is dominated by altered metabolism: kynurenine and iron in microglia, cholesterol in oligodendrocytes and glutamate in astroytes. Other alterations include altered cannabinoid signalling in microglia and altered potassium channel expression in astrocytes. Many of the alterations in HD, such as those in oligodendrocytes and microglia, are found in asymptomatic HD gene carriers and worsen with disease progression. Alterations in oligodendrocytes can be detected using neuroimaging, offering a potential method of monitoring disease progression. Many of the glial metabolic defects in HD represent potential therapeutic targets for the treatment of htis most devestating disease. Here, we will review the role of glial cells in HD.
P6.7. Role of glial cells in fragile-x syndrome Jennifer Smith M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Jennifer Smith [email protected]
Fragile X-Syndrome (FXS) is a neurodevelopmental disorder, and is the most common inherited form of intellectual disability. It is caused by a mutation in the Fmr1 gene, where there are an excessive number of CGG repeats, and as a result gene silencing occurs and the gene is subsequently unable to encode the Fragile -Xmental retardation protein (FRMP). FMRP is a key translational repressor of proteins involved in synaptic development, plasticity and myelination, and loss of this protein leads to the development of the cognitive defects seen in FXS. It has been widely established that glial cells play crucial roles in the CNS, and thus it has been hypothesised that dysfunction or abnormalities in glial cells, or lack of FMRP within these cells contributes to the development of FXS. This disorder is characterised by an impaired neuronal network performance. In addition, however, it has been demonstrated that FXS astrocytes are unable to support normal neuronal growth. The
S17 lack or absence of astrocyte derived FMRP is thus believed to affect dendritic spine morphology and synaptic development in FXS. Evidence also suggests that synaptic pruning mediated by microglia is important in early brain development. Further, it has been hypothesised that insufficient synaptic pruning, where microglia play a role, occurs in FXS. Lastly, the timing of myelination by oligodendrocytes is crucial for the normal development of neurons and the delayed myelination is believed to contribute to the cognitive defects seen in FXS. In this article the roles of glial cells and their effects on synaptic plasticity, pruning and development will be presented.
P6.8. The role of glial cells in ALS Alexander Robinson M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Alexander Robinson [email protected]
Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disorder affecting both lower and upper motor neurons, so named due to the characteristic muscle cell atrophy and the scarring of the lateral sides of the spinal cord. ALS is characterised by initial symptoms of muscle weakness and atrophy, difficulty speaking or swallowing, and cramping. The median survival from time of first symptom onset is 2.9 years, the most common cause of death being respiratory failure. Most cases are idiopathic (Sporadic ALS, sALS), although 10 % of cases are found to have a genetic component (Familial ALS, fALS). While in the past ALS was regarded as a disease only of motor neurons, recent studies have brought to light the role of glial cells in its pathogenesis. Astrocytes have several functions in the central nervous system (CNS), from regulation of synaptic transmissions to astrogliosis in response to CNS injury or insult. Mutations of superoxide dismutase 1 (SOD1), an enzyme involved in regulation off superoxide free radicals, is found to be mutated in astrocytes of many patients with ALS. Dysregulation of neurotransmitter control by astrocytes and subsequent excitotoxicity is also believed to play a role in ALS. In addition, since neuroinflammation is involved in the pathogenesis of ALS, it is believed that microglia also play a pivotal role. Lastly, reduced myelination is also commonly seen in ALS, where dysfunction in oligodendrocytes may alter conduction of action potentials, neuronal development and survival. Taken together, many recent advances in our understanding of ALS pathology has brought to light the multiple roles which glial cells play. These glial cells thus offer many potential novel therapeutic targets. Here the role of glia cells in ALS will be reviewed.
P6.9. The role of glia in the pathophsysiology of Rett sydrome Claire McGrory M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Claire McGrory [email protected]
S18 Rett Syndrome (RTT) is a neurodevelopmental disorder found mainly in females. Symptoms present at 6 months, after which the disease progresses, affecting motor and language skills. This illness has been linked to mutations in the MECP2 gene that has been shown to control the expression of many genes involved in the development of the CNS. Autopsies of Retts patients show their brains exhibit no signs of degeneration or cell death but changes in the morphology of synapses are present, including reduced dendritic branching, spine density and axonal boutons. Until recently, research into RTT has focused on neurons. Glia cells are now gaining interest and have been implicated in the pathology of Retts because of their roles in neurodevelopment. Astrocytes expressing the mutated MECP2 gene have been shown to compromise the development of neurons and functional synapses and show an increased expression of GFAP, a hallmark of reactive gliosis. Similar to this, MECP2-negative microglia inhibit normal neural development and restoring normal microglia improves the symptoms of Retts. Studies have also indicated that astrocytes and microglia could be linked to the disease through altered glutamate metabolism and supressed BDNF release. Although no demyelination is present in Retts, oligodendrocytes may contribute to the disease through defective myelin proteins, which could depress neurotransmission. There is increasing evidence that alterations in the function of all three glia cells are behind the pathology of Retts and are a potential target for treatment of the disorder. Here the role of glial cells in Retts will be explored.
P6.10. The role of glia in angelman syndrome John Zach Conlon M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland
Ir J Med Sci (2015) 184 (Suppl 1):S1–S18
P6.11. The role of neuroglia in Charcot-Marie-tooth disease Peter Lalor M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Peter Lalor [email protected]
Charcot-Marie-Tooth (CMT) disease is the most common hereditary peripheral neuropathy, affecting 1 in 2,500 with a progressive motor and sensory deficiency with a predilection for the lower limbs. CMT comprises a complex and heterogeneous constellation of demyelinating and axonal neuropathies with over 900 mutations of 70 causative genes recognised thus far. Despite this, mutations in just two genes, PMP22 and GJB1, account for the majority of cases through the major subtypes CMT1A and CMT1X, respectively. Neuroglia, the nominal and functional glue of the central nervous system, are indispensable to brain homeostasis. In CMT the length-dependent axonal degeneration or demyelination is primarily peripheral and neuroglia may react centrally to nerve injury via purinergic signalling. Chronically or acutely damaged nerves release ATP which acts via astrocytic and microglial ionotropic P2X and metabotropic P2Y receptors. Signalling in concert with fractalkine and CCL21, this induces astrogliosis and microglial activation and migration in the spinal distribution of the peripheral nerve. These pathologic events lead to the release of inflammatory factors which alter signalling in spinal interneurons from inhibitory to excitatory and may be responsible for the high incidence of neuropathic pain seen in CMT. In addition, a mutation of the oligodendrocyte gap junction connexin Cx32, implicated in signalling in the myelin sheath and in astrocyte-oligodendrocyte coupling, may contribute to the usually subclinical but sometimes severe central pathology seen in CMT1X. These pathologic processes serve to highlight the central roles neuroglia play in this complex disease of the periphery and will be presented here.
Presenting Author: John Zach Conlon [email protected]
Angelman Syndrome is a genetic condition that affects neurologic development and function. The most common symptoms of Angelman Syndrome are mental retardation, seizures, ataxia, speech impairment, and an unusually happy demeanor with frequent bouts of uncontrollable laughter. Angelman Syndrome is caused by loss of function of the maternal copy of the UBE3A gene. The loss of function can be caused by mutation, deletion, or uniparental disomy. Because the paternal copy of the UBE3A gene is silenced in certain parts of the brain, such as the hippocampus and cerebellum, only dysfunction of the maternal copy of the gene causes Angelman Syndrome. Angelman Syndrome does not directly affect glial cells because glial cells express both copies of the UBE3A gene, even glial cells in the hippocampus and cerebellum. Despite this, glial cells may still be a significant contributor to the symptoms of Angelman Syndrome, given their roles in the CNS. In particular, UBE3A is a ubiquitin-protein ligase that is required for post-translational modifications to certain proteins and lipids, including the majority of CNS signaling molecules. It is thus conceivable that impairment of such signaling events may cause abnormal neuron-glia communication. For example, astrocytes guide immature neuron migration, microglia prune synapses during neural circuit formation, and oligodendrocytes regulate the finalization of neural circuits. The activity of glia during neurodevelopment requires precise intercellular communication to function properly and so impairment leads to irregular neurodevelopment. The aberrant function of these processes in glial cells and possible hypothetical roles in Angelmans Syndrome will be reviewed here.
P6.12. The role of glial cells in niemann pick type C Sea´n O’Leary M.Sc. Neuroscience Course, Cellular Neuroscience Module, Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland Presenting Author: Sea´n O’Leary [email protected]
Niemann Pick type C disease (NP-C) is an atypical lysosomal storage disorder that results in severe psychiatric, neurological and physical manifestations. Premature death is a hallmark of the disease. In this disease, dysregulation of the NPC1/NPC2 cholesterol trafficking pathway of the lysosome causes excessive lipid build up and cellular dysfunction. Altered lipid metabolism and reduced cellular ability are thought to be the basis for disease symptomology. Here, the effects of dysregulation of NPC1/NPC2 in glia will be summarized. Firstly, astrocytes will be discussed. In particular the possible role that Bergmann Glia play in the death of Purkinje cells of the cerebellum will be illustrated. Secondly, it has become clear that microglia contribute to global neurodegeneration and cognitive decline via inappropriate activation. Abnormal microglial expansion adds to disease burden by promoting an inflammatory response, which damages neuronal tissue. Finally, the role of oligodendrocytes will be discussed. Dysmelination is thought to occur in this disease, and once again, the inappropriate death of Purkinje neurons can be explained via dysfunction of oligodendrocytes.