Cell Biology International ISSN 1065-6995 doi: 10.1002/cbin.10451
COMMENTARY
Resveratrol in spermatogenesis Salvatore Chirumbolo Department of Medicine, University of Verona, LURM Est Policlinico GB Rossi, Piazzale L. A. Scuro 10 37134, Verona, Italy
A recent article by Enzhong Li et al., reported the effect of trans-resveratrol (trans-3,5,4’-trihydroxystilbene) on spermatogenesis in experimental cryptorchid mice (Li et al., 2015). In this study, the phytoalexin behaved as a phytoestrogen, as it increased primary spermatocytes through an hormone-like activity in sterile-induced animals by cryptorchidism in mice. The authors did not deepen the mechanism by which resveratrol is able to promote spermatogenesis or restore it in cryptorchid animals but some suggestion may come from the role of this flavonoid in cell cycle and apoptosis. Plant derived flavonoids and stilbenoids, exert either pro- or anti-apoptotic action. Usually pro-apoptosis effects are shown in low stressresponding cells, such as cancer cells. As a matter of fact, the phytoestrogenic potential of resveratrol has been mainly reported in prostate cancer, where this grapefruit-derived stilbene exerts a chemopreventive action via the regulation of sex steroid receptor and increasing androgen receptor gene expression (Harper et al., 2007). The role of androgen receptor (AR) in spermatogenesis has been reviewed (Wang et al., 2009). According to some reports, resveratrol seems to inhibit androgen receptor dimerization (Streicher et al., 2014) and its IL-6 induced transcriptional activity (Lee et al., 2014) in prostate cancer cells. This activity is in contrast with the evidence reported by Li et al. (2015), if primary spermatocytes increase is to be related to AR function and testosterone stimulation (Wang et al., 2009; Li et al., 2015). The phytoestrogenic activity of resveratrol upon AR has been particularly investigated in prostate cancer, where resveratrol stimulates phosphatase and tensin homolog deleted on chromosome 10 (PTEN) through AR inhibition (Wang et al., 2010). This mechanism, if assessed in cryptorchid mouse testis, should reduce rather than increase primary spermatocytes, because elevated PTEN in testis may attenuate the Kit/PI3K/Akt pathway and increase germ cell
apoptosis (Dong et al., 2014). However, the authors did not clarify if the increase in primary spermatocytes resulted from a spermatogenesis arrest at the diplotene primary spermatocyte stage prior to the accomplishment of first meiotic division, an effect reported for male AR knockout mice (Wang et al., 2009). In this circumstance, resveratrol, by inhibiting AR activity, may induce the accumulation of diplotene arrested primary spermatocytes in the seminiferous tube. The authors reported that resveratrol was correlated with enhancing activity on testosterone, manifested as an increase in spermatogenesis in cryptorchid mice. In testis, the activity of resveratrol may involve some transcription factors affecting the function of the androgen receptor (Smith and Walker, 2014). For example, the testis zinc finger protein (Tzfp), which is also known as repressor of GATA and belongs to the BTB/POZ zinc finger family of transcription factors, is remarkably expressed in testis and plays a major role in spermatogenesis. At least in some cell models, repression of GATA negatively regulates PTEN (Wang et al., 2012). and this is believed to promote spermatogenesis by reducing PTEN activity in promoting spermatogonia apoptosis. It has been recently reported that Sertoli cells in testes lacking Tzfp display an increased androgen receptor signaling and this was paralleled with higher expression of several genes in the testis, including Gata1, Aie1, and Fank1 (Furu and Klungland, 2013). Particularly resveratrol was reported to affect the participation for Aurora C kinases (AIE1 in mouse) in apoptosis (Roccaro et al., 2008) and moreover, increased sperm number is associated with expression of Fank1 gene (Dong et al., 2014). Therefore, the role of resveratrol on spermatogonia apoptosis appears as a hallmark and contrast with the suggested role of resveratrol to increase primary spermatocytes in mouse testes. It is clear that further investigation on the effect of
Corresponding author: e-mail: [email protected] Abbreviations: Aie1, an Aurora-C serine/threonine kinase gene; Akt, protein kinase B; BTB/POZ, BR-C ttk and bab þ Pox virus and zinc finger domain; Fank1, fibronectin type III and ankyrin repeat domains 1; GATA, a transcription factor binding to a DNA GATA sequence; IL-6, interleukin 6; kit, tyrosine kinase kit or CD117; PI3K, phosphoinositide-3-kinase
Cell Biol Int 39 (2015) 775–776 © 2015 International Federation for Cell Biology
775
Resveratrol in spermatogenesis
resveratrol on this signaling pathway is needed to shed light on the role exerted by this stilbenoid on spermatogenesis. In addition, resveratrol can up-regulate gene expression of spermatogenesis and oogenesis specific basic helix-loophelix 2 (Sohlh2), a gene that should be required for progression of differentiating type-A spermatogonia into type-B spermatogonia (Iwamori, 2014; Li et al., 2015). Interestingly, SOHLH2 has been reported to modulate STRA8 (Stimulated by Retinoic Acid 8), an early retinoic acid (RA) responsive gene, which is pivotal for the beginning of meiosis in female and male germ cells (Desimio et al., 2015). It would be very interesting to assess if resveratrol affects the apoptotic machinery during spermatogenesis leading to sperm increase as regulation of apoptosis in spermatogenesis plays a major role in the amount of viable sperms. Further research on the effect of resveratrol on some critical factor involved in spermatogenesis, such as FANK1, may highlight the role of this stilbene on testes functionality (Wang et al., 2011), particularly under stressing conditions such as cryptorchidism. Conflict of interest None. References Desimio MG, Campolo F, Dolci S, De Felici M, Farini D (2015) SOHLH1 and SOHLH2 directly down-regulate Stimulated by Retinoic Acid 8 (STRA8) expression. Cell Cycle Jan 20:0. Dong Y, Zhang L, Bai Y, Zhou HM, Campbell AM, Chen H, Yong W, Zhang W, Zeng Q, Shou W, Zhang ZY (2014) Phosphatase of regenerating liver 2 (PRL2) deficiency impairs Kit signaling and spermatogenesis. J Biol Chem 289: 3799–810. Dong WW, Huang HL, Yang W, Liu J, Yu Y, Zhou SL, Wang W, Lv XC, Li ZY, Zhang MY, Zheng ZH, Yan W (2014) Testisspecific Fank1 gene in knockdown mice produces oligospermia via apoptosis. Asian J Androl 16: 124–30. Furu K, Klungland A (2013) Tzfp represses the androgen receptor in mouse testis. PLoS One 8: e62314. Harper CE, Patel BB, Wang J, Arabshahi A, Eltoum IA, Lamartiniere CA (2007) Resveratrol suppresses prostate cancer progression in transgenic mice. Carcinogenesis 28: 1946–53.
776
S. Chirumbolo
Iwamori N (2014) Regulation of spermatogonial stem cell compartment in the mouse testis. Fukuoka Igaku Zasshi 105: 1–10. Lee MH, Kundu JK, Keum YS, Cho YY, Surh YJ, Choi BY (2014) Resveratrol Inhibits IL-6-Induced Transcriptional Activity of AR and STAT3 in Human Prostate Cancer LNCaP-FGC Cells. Biomol Ther (Seoul) 22: 426–30. Li E, Guo Y, Wang G, Shen F, Li Q (2015) Effect of resveratrol on restoring spermatogenesis in experimental cryptorchid mice and analysis of related differentially expressed proteins. Cell Biol Int doi: 10.1002/cbin.10441 Roccaro AM, Leleu X, Sacco A, Moreau AS, Hatjiharissi E, Jia X, Xu L, Ciccarelli B, Patterson CJ, Ngo HT, Russo D, Vacca A, Dammacco F, Anderson KC, Ghobrial IM, Treon SP (2008) Resveratrol exerts antiproliferative activity and induces apoptosis in Waldenstr€ om’s macroglobulinemia. Clin Cancer Res 14: 1849–58. Smith LB, Walker WH (2014) The regulation of spermatogenesis by androgens. Semin Cell Dev Biol 30: 2–13. Streicher W, Luedeke M, Azoitei A, Zengerling F, Herweg A, Genze F, Schrader MG, Schrader AJ, Cronauer MV (2014) Stilbene induced inhibition of androgen receptor dimerization: implications for AR and ARDLBD-signalling in human prostate cancer cells. PLoS One 9: e98566. Wang Y, Romigh T, He X, Orloff MS, Silverman RH, Heston WD, Eng C (2010) Resveratrol regulates the PTEN/AKT pathway through androgen receptor-dependent and -independent mechanisms in prostate cancer cell lines. Hum Mol Genet 19: 4319–29. Wang RS, Yeh S, Tzeng CR, Chang C (2009) Androgen receptor roles in spermatogenesis and fertility: lessons from testicular cell-specific androgen receptor knockout mice. Endocr Rev 30: 119–32. Wang H, Song W, Hu T, Zhang N, Miao S, Zong S, Wang L (2011) Fank1 interacts with Jab1 and regulates cell apoptosis via the AP-1 pathway. Cell Mol Life Sci 68: 2129–39. Wang Y, He X, Ngeow J, Eng C (2012) GATA2 negatively regulates PTEN by preventing nuclear translocation of androgen receptor and by androgen-independent suppression of PTEN transcription in breast cancer. Hum Mol Genet 21: 569–76. Received 27 January 2015; revised 4 February 2015; accepted 7 February 2015. Final version published online 26 February 2015.
Cell Biol Int 39 (2015) 775–776 © 2015 International Federation for Cell Biology
COMMENTARY
Resveratrol in spermatogenesis Salvatore Chirumbolo Department of Medicine, University of Verona, LURM Est Policlinico GB Rossi, Piazzale L. A. Scuro 10 37134, Verona, Italy
A recent article by Enzhong Li et al., reported the effect of trans-resveratrol (trans-3,5,4’-trihydroxystilbene) on spermatogenesis in experimental cryptorchid mice (Li et al., 2015). In this study, the phytoalexin behaved as a phytoestrogen, as it increased primary spermatocytes through an hormone-like activity in sterile-induced animals by cryptorchidism in mice. The authors did not deepen the mechanism by which resveratrol is able to promote spermatogenesis or restore it in cryptorchid animals but some suggestion may come from the role of this flavonoid in cell cycle and apoptosis. Plant derived flavonoids and stilbenoids, exert either pro- or anti-apoptotic action. Usually pro-apoptosis effects are shown in low stressresponding cells, such as cancer cells. As a matter of fact, the phytoestrogenic potential of resveratrol has been mainly reported in prostate cancer, where this grapefruit-derived stilbene exerts a chemopreventive action via the regulation of sex steroid receptor and increasing androgen receptor gene expression (Harper et al., 2007). The role of androgen receptor (AR) in spermatogenesis has been reviewed (Wang et al., 2009). According to some reports, resveratrol seems to inhibit androgen receptor dimerization (Streicher et al., 2014) and its IL-6 induced transcriptional activity (Lee et al., 2014) in prostate cancer cells. This activity is in contrast with the evidence reported by Li et al. (2015), if primary spermatocytes increase is to be related to AR function and testosterone stimulation (Wang et al., 2009; Li et al., 2015). The phytoestrogenic activity of resveratrol upon AR has been particularly investigated in prostate cancer, where resveratrol stimulates phosphatase and tensin homolog deleted on chromosome 10 (PTEN) through AR inhibition (Wang et al., 2010). This mechanism, if assessed in cryptorchid mouse testis, should reduce rather than increase primary spermatocytes, because elevated PTEN in testis may attenuate the Kit/PI3K/Akt pathway and increase germ cell
apoptosis (Dong et al., 2014). However, the authors did not clarify if the increase in primary spermatocytes resulted from a spermatogenesis arrest at the diplotene primary spermatocyte stage prior to the accomplishment of first meiotic division, an effect reported for male AR knockout mice (Wang et al., 2009). In this circumstance, resveratrol, by inhibiting AR activity, may induce the accumulation of diplotene arrested primary spermatocytes in the seminiferous tube. The authors reported that resveratrol was correlated with enhancing activity on testosterone, manifested as an increase in spermatogenesis in cryptorchid mice. In testis, the activity of resveratrol may involve some transcription factors affecting the function of the androgen receptor (Smith and Walker, 2014). For example, the testis zinc finger protein (Tzfp), which is also known as repressor of GATA and belongs to the BTB/POZ zinc finger family of transcription factors, is remarkably expressed in testis and plays a major role in spermatogenesis. At least in some cell models, repression of GATA negatively regulates PTEN (Wang et al., 2012). and this is believed to promote spermatogenesis by reducing PTEN activity in promoting spermatogonia apoptosis. It has been recently reported that Sertoli cells in testes lacking Tzfp display an increased androgen receptor signaling and this was paralleled with higher expression of several genes in the testis, including Gata1, Aie1, and Fank1 (Furu and Klungland, 2013). Particularly resveratrol was reported to affect the participation for Aurora C kinases (AIE1 in mouse) in apoptosis (Roccaro et al., 2008) and moreover, increased sperm number is associated with expression of Fank1 gene (Dong et al., 2014). Therefore, the role of resveratrol on spermatogonia apoptosis appears as a hallmark and contrast with the suggested role of resveratrol to increase primary spermatocytes in mouse testes. It is clear that further investigation on the effect of
Corresponding author: e-mail: [email protected] Abbreviations: Aie1, an Aurora-C serine/threonine kinase gene; Akt, protein kinase B; BTB/POZ, BR-C ttk and bab þ Pox virus and zinc finger domain; Fank1, fibronectin type III and ankyrin repeat domains 1; GATA, a transcription factor binding to a DNA GATA sequence; IL-6, interleukin 6; kit, tyrosine kinase kit or CD117; PI3K, phosphoinositide-3-kinase
Cell Biol Int 39 (2015) 775–776 © 2015 International Federation for Cell Biology
775
Resveratrol in spermatogenesis
resveratrol on this signaling pathway is needed to shed light on the role exerted by this stilbenoid on spermatogenesis. In addition, resveratrol can up-regulate gene expression of spermatogenesis and oogenesis specific basic helix-loophelix 2 (Sohlh2), a gene that should be required for progression of differentiating type-A spermatogonia into type-B spermatogonia (Iwamori, 2014; Li et al., 2015). Interestingly, SOHLH2 has been reported to modulate STRA8 (Stimulated by Retinoic Acid 8), an early retinoic acid (RA) responsive gene, which is pivotal for the beginning of meiosis in female and male germ cells (Desimio et al., 2015). It would be very interesting to assess if resveratrol affects the apoptotic machinery during spermatogenesis leading to sperm increase as regulation of apoptosis in spermatogenesis plays a major role in the amount of viable sperms. Further research on the effect of resveratrol on some critical factor involved in spermatogenesis, such as FANK1, may highlight the role of this stilbene on testes functionality (Wang et al., 2011), particularly under stressing conditions such as cryptorchidism. Conflict of interest None. References Desimio MG, Campolo F, Dolci S, De Felici M, Farini D (2015) SOHLH1 and SOHLH2 directly down-regulate Stimulated by Retinoic Acid 8 (STRA8) expression. Cell Cycle Jan 20:0. Dong Y, Zhang L, Bai Y, Zhou HM, Campbell AM, Chen H, Yong W, Zhang W, Zeng Q, Shou W, Zhang ZY (2014) Phosphatase of regenerating liver 2 (PRL2) deficiency impairs Kit signaling and spermatogenesis. J Biol Chem 289: 3799–810. Dong WW, Huang HL, Yang W, Liu J, Yu Y, Zhou SL, Wang W, Lv XC, Li ZY, Zhang MY, Zheng ZH, Yan W (2014) Testisspecific Fank1 gene in knockdown mice produces oligospermia via apoptosis. Asian J Androl 16: 124–30. Furu K, Klungland A (2013) Tzfp represses the androgen receptor in mouse testis. PLoS One 8: e62314. Harper CE, Patel BB, Wang J, Arabshahi A, Eltoum IA, Lamartiniere CA (2007) Resveratrol suppresses prostate cancer progression in transgenic mice. Carcinogenesis 28: 1946–53.
776
S. Chirumbolo
Iwamori N (2014) Regulation of spermatogonial stem cell compartment in the mouse testis. Fukuoka Igaku Zasshi 105: 1–10. Lee MH, Kundu JK, Keum YS, Cho YY, Surh YJ, Choi BY (2014) Resveratrol Inhibits IL-6-Induced Transcriptional Activity of AR and STAT3 in Human Prostate Cancer LNCaP-FGC Cells. Biomol Ther (Seoul) 22: 426–30. Li E, Guo Y, Wang G, Shen F, Li Q (2015) Effect of resveratrol on restoring spermatogenesis in experimental cryptorchid mice and analysis of related differentially expressed proteins. Cell Biol Int doi: 10.1002/cbin.10441 Roccaro AM, Leleu X, Sacco A, Moreau AS, Hatjiharissi E, Jia X, Xu L, Ciccarelli B, Patterson CJ, Ngo HT, Russo D, Vacca A, Dammacco F, Anderson KC, Ghobrial IM, Treon SP (2008) Resveratrol exerts antiproliferative activity and induces apoptosis in Waldenstr€ om’s macroglobulinemia. Clin Cancer Res 14: 1849–58. Smith LB, Walker WH (2014) The regulation of spermatogenesis by androgens. Semin Cell Dev Biol 30: 2–13. Streicher W, Luedeke M, Azoitei A, Zengerling F, Herweg A, Genze F, Schrader MG, Schrader AJ, Cronauer MV (2014) Stilbene induced inhibition of androgen receptor dimerization: implications for AR and ARDLBD-signalling in human prostate cancer cells. PLoS One 9: e98566. Wang Y, Romigh T, He X, Orloff MS, Silverman RH, Heston WD, Eng C (2010) Resveratrol regulates the PTEN/AKT pathway through androgen receptor-dependent and -independent mechanisms in prostate cancer cell lines. Hum Mol Genet 19: 4319–29. Wang RS, Yeh S, Tzeng CR, Chang C (2009) Androgen receptor roles in spermatogenesis and fertility: lessons from testicular cell-specific androgen receptor knockout mice. Endocr Rev 30: 119–32. Wang H, Song W, Hu T, Zhang N, Miao S, Zong S, Wang L (2011) Fank1 interacts with Jab1 and regulates cell apoptosis via the AP-1 pathway. Cell Mol Life Sci 68: 2129–39. Wang Y, He X, Ngeow J, Eng C (2012) GATA2 negatively regulates PTEN by preventing nuclear translocation of androgen receptor and by androgen-independent suppression of PTEN transcription in breast cancer. Hum Mol Genet 21: 569–76. Received 27 January 2015; revised 4 February 2015; accepted 7 February 2015. Final version published online 26 February 2015.
Cell Biol Int 39 (2015) 775–776 © 2015 International Federation for Cell Biology
