ABSTRACT

Zearalenone (ZEA), a mycotoxin, is known to impair reproductive capability by disrupting the synthesis and secretion of testosterone by Leydig cells (LCs), although the mechanism is unknown. Robust rhythmicity of circadian clock and steroidogenic genes were identified in LCs. The aim of this study was to examine whether ZEA significantly attenuated the transcription of core clock genes (Bmal1, Dbp, Per2, and Nr1d1) as well as steroidogenic genes (StAR, Hsd3b2, and Cyp11a1) in mouse testis Leydig cell line (TM3). Western blotting confirmed declines in BMAL1, NR1D1, and StAR protein levels. ZEA also suppressed secreted testosterone levels. In primary LCs, isolated from PER2::LUCIFERASE reporter gene knock in mice, ZEA diminished the amplitude of PER2::LUC expression, and induced a phase shift and period extension. In primary LCs, ZEA also suppressed the expression levels of core clock and steroidogenic genes, reduced protein levels of BMAL1, and decreased testosterone secretion. In vivo expression of core clock and steroidogenic genes were reduced in testes of mice exposed to ZEA for 1 week leading to decreased serum testosterone levels. In summary, data suggest that ZEA may impair testosterone synthesis through attenuation of the circadian clock in LCs culminating in reproductive dysfunction in male mammals .

摘要

玉米赤霉烯酮 (ZEA) 是一种真菌毒素，已知会通过破坏 Leydig 细胞 (LC) 合成和分泌睾酮来损害生殖能力，但其机制尚不清楚。在 LC 中鉴定出生物钟和类固醇生成基因的稳健节律性。本研究的目的是检查 ZEA 是否显着减弱核心时钟基因（Bmal1、Dbp、Per2和Nr1d1）以及类固醇生成基因（StAR、Hsd3b2和Cyp11a1）的转录。) 在小鼠睾丸间质细胞系 (TM3) 中。蛋白质印迹证实 BMAL1、NR1D1 和 StAR 蛋白水平下降。ZEA 还抑制分泌的睾酮水平。在从小鼠 PER2::LUCIFERASE 报告基因敲除中分离的初级 LC​​ 中，ZEA 降低了PER2::LUC表达的幅度，并诱导了相移和周期延长。在原发性 LC 中，ZEA 还抑制了核心时钟和类固醇生成基因的表达水平，降低了 BMAL1 的蛋白质水平，并减少了睾酮分泌。体内暴露于 ZEA 1 周的小鼠睾丸中核心时钟和类固醇生成基因的表达降低，导致血清睾酮水平降低。总之，数据表明，ZEA 可能通过减弱 LC 中的生物钟来损害睾酮合成，最终导致雄性哺乳动物的生殖功能障碍。