Melatonin up-regulates the expression of the GATA-4 transcription factor and increases testosterone secretion from Leydig cells through RORα signaling in an in vitro goat spermatogonial stem cell differentiation culture system.

Yan Zhang,Shou-Long Deng,De-Ping Han,Yi-Xun Liu,Xiu-Xia Wang,Su-Ren Chen,C Yan Cheng,Kun Yu,Zheng-Xing Lian

doi:10.18632/oncotarget.22855

Abstract

Because androgen function is regulated by its receptors, androgen-androgen receptor signaling is crucial for regulating spermatogenesis. Androgen is mainly testosterone secreted by testis. Based on the results of early studies in goats, the administration of melatonin over an extended period of time increases steroid production, but the underlying mechanism remains unclear. Here, we report the expression of the melatonin membrane receptors MT1 and MT2 and the retinoic acid receptor-related orphan receptor-alpha (RORα) in the goat testis. An in vitro differentiation system using spermatogonial stem cells (SSCs) cultured in the presence of testicular somatic cells was able to support the formation of sperm-like cells with a single flagellum. The addition of 10-7 M melatonin to the in vitro culture system increased RORα expression and considerably improved the efficiency of haploid cell differentiation, and the addition of the RORα agonist CGP52608 significantly increased the testosterone concentration and expression of GATA binding factor 4 (GATA-4). Furthermore, inhibitors of melatonin membrane receptors and a RORα antagonist (T0901317) also led to a considerable reduction in the efficiency of haploid spermatid formation, which was coupled with the suppression of GATA-4 expression. Based on these results, RORα may play a crucial role in enhancing melatonin-regulated GATA-4 transcription and steroid hormone synthesis in the goat spermatogonial stem cell differentiation culture system.

Highlights

Based on earlier findings from our laboratory, melatonin promotes the differentiation of spermatogonia into functional haploid cells in the testes of the Suffolk ram [1]
According to the real-time PCR analysis, both MT1 and MT2 were expressed in the goat testes, and their expression decreased as a function of increasing age
Melatonin is involved in the function of the male reproductive system, the testes, since Leydig cells are sensitive to melatonin [42, 43]

Summary

INTRODUCTION

Based on earlier findings from our laboratory, melatonin promotes the differentiation of spermatogonia into functional haploid cells in the testes of the Suffolk ram [1]. We used an in vitro cell culture system that mimics the testes in vivo to determine whether retinoic acid receptor-related orphan receptor-alpha (RORα/NR1F1) signaling is involved www.impactjournals.com/oncotarget in melatonin-promoted goat haploid spermatid production. Melatonin regulates the transcription of animal reproduction genes by binding nuclear receptors [24, 25]. By binding to its receptors, melatonin directly influences androgen production by Leydig cells [35], which in turn affects testis development in mice [36]. We provide further evidence that RORα increases melatonin-regulated steroid hormone synthesis and SSC differentiation in an in vitro Saanen goat SSC/testis somatic cell culture. These findings provide insights into the treatment of diseases caused by androgen deficiency

RESULTS

DISCUSSION

Ethics statement