Sirt1 m6A修饰诱导的Leydig细胞衰老促进镉诱导的睾酮下降

Sirt1 m6A modification-evoked Leydig cell senescence promotes Cd-induced testosterone decline

Sirt1 m6A修饰诱导的Leydig细胞衰老促进镉诱导的睾酮下降

Authors: Zheng XM, Zhang XD, Tan LL, Zhang J, Wang TT, Ling Q, Wang H, Ouyang KW, Wang KW, Chang W, Li H, Zhu HL, Xiong YW, Wang H.

Source：Ecotoxicol Environ Saf. 2024 Aug 16;284:116884. doi: 10.1016/j.ecoenv.2024.116884.

Abstract

Diminished testosterone levels have been documented as a key factor in numerous male health disorders. Both human and animal studies have consistently demonstrated that cadmium (Cd), a pervasive environmental heavy metal, results in decreased testosterone levels. However, the exact mechanism through which Cd interferes with testosterone synthesis remains incompletely elucidated. This research sought to examine the impact of cellular senescence on Cd-suppressed testosterone synthesis. We also investigated the related m6A modification mechanism. The results demonstrated that Cd (100 mg/L) led to a decrease in testosterone levels, along with downregulated expression of testosterone synthase in C57BL/6 N male mice. Furthermore, Cd significantly increased β-galactosidase staining intensity, senescence-related proteins, and senescence-related secretory phenotypes in mouse testicular Leydig cells. Subsequent investigations revealed that Cd decreased the mRNA and protein levels of NAD-dependent deacetylase Sirtuin-1 (SIRT1) in Leydig cells. Mechanistically, mice treated with resveratrol (50 mg/kg), a specific SIRT1 activator, mitigated Leydig cell senescence and reversed Cd-reduced testosterone levels in mouse testes. These effects were also restored by SIRT1 overexpression in Leydig cells. Additionally, we found that Cd increased the level of methyltransferase enzyme METTL3 and Sirt1 m6A modification in Leydig cells. Mettl3 siRNA effectively restored Cd-enhanced Sirt1 m6A level and reversed Cd-downregulated Sirt1 mRNA expression in Leydig cells. Overall, our findings suggest that Cd exposure inhibits testosterone synthesis via Sirt1 m6A modification-mediated senescence in mouse testes. These results offer an experimental basis for investigating the causes and potential treatments of hypotestosteronemia induced by environmental factors.

Keywords: Cadmium; Cell senescence; M6A modification; SIRT1; Testosterone.

摘要

据记录，睾酮水平下降是许多男性健康疾病的一个关键因素。人类和动物研究都一致表明，镉（Cd），一种普遍存在的环境重金属，导致睾酮水平下降。然而，镉干扰睾酮合成的确切机制仍不完全阐明。本研究旨在研究细胞衰老对镉抑制睾酮合成的影响。我们还研究了相关的m6 A修饰机制。结果表明，Cd（100 mg/L）可导致C57 BL/6 N雄性小鼠睾酮水平下降，同时沿着睾酮合成酶表达下调。此外，镉显着增加β-半乳糖苷酶染色强度，衰老相关蛋白，衰老相关的分泌表型在小鼠睾丸Leydig细胞。随后的研究表明，镉降低NAD依赖的去乙酰化酶Sirtuin-1（SIRT 1）在Leydig细胞的mRNA和蛋白水平。从机制上讲，用白藜芦醇（50 mg/kg）（一种特异性SIRT 1激活剂）治疗的小鼠减轻了Leydig细胞衰老，并逆转了小鼠睾丸中Cd降低的睾酮水平。这些影响也恢复SIRT 1在Leydig细胞过表达。此外，我们发现，镉增加了睾丸间质细胞中的甲基转移酶胃L3和Sirt 1 m6 A修饰的水平。Mettl 3 siRNA能有效恢复镉诱导的睾丸间质细胞Sirt 1 m6 A表达水平，逆转镉诱导的Sirt 1 mRNA表达下调。总体而言，我们的研究结果表明，镉暴露抑制睾酮合成通过Sirt 1 m6 A修饰介导的小鼠睾丸衰老。这些结果为探讨环境因素引起的低睾酮血症的原因和可能的治疗方法提供了实验依据。

关键词：镉;细胞衰老; M6 A修饰; SIRT 1;泰乐