Third-grade Pharmacological Laboratory on Traditional Chinese Medicine, State Administration of Traditional Chinese Medicine, China Three Gorges University, Yichang, Hubei, 443002, China; College of Basic Medical Sciences, China Three Gorges University, Yichang, Hubei, 443002, China.
College of Medicine and Health Sciences, China Three Gorges University, Yichang, Hubei, 443002, China.
Food Chem Toxicol. 2023 Mar;173:113649. doi: 10.1016/j.fct.2023.113649. Epub 2023 Feb 2.
Perfluorooctanoic acid (PFOA), a man-made chemical widely used in consumers, could cause male reproductive toxicity by disrupting blood-testis barrier (BTB) integrity. Autophagy in Sertoli cells is essential for regulation of spermatogenesis and BTB. However, it remains a mystery that whether PFOA-induced BTB injury is associated with autophagy in Sertoli cells. In this study, we found that PFOA dose-dependently disrupted tight junction (TJ) function in Sertoli cells in vivo and in vitro. Furthermore, the results from transmission electron microscopy, Western blot and immunofluorescence analysis revealed that PFOA induced the accumulation of autophagosome in testicular Sertoli cells as well as TM4 cells. Further study confirmed that autophagosome accumulation resulted from the blockage of autophagic degradation because of disruption of autophagosome and lysosome fusion via downregulation of the expression of α-SNAP. In parallel, the overexpressed MMP9 was also observed in vivo and in vitro. Conversely, overexpression of α-SNAP inhibited the expression of MMP9 in TM4 cells. In conclusion, PFOA blocks autophagic flux through downregulating the expression levels of α-SNAP in Sertoli cells, and then induces the accumulation of MMP9 leading to disruption of TJ function. This finding will provide clues for effective prevention and treatment of PFOA-induced male reproductive toxicity.
全氟辛酸（PFOA）是一种广泛应用于消费品的人造化学物质，它可以通过破坏血睾屏障（BTB）的完整性来引起雄性生殖毒性。支持细胞中的自噬对于调节精子发生和 BTB 是必不可少的。然而，PFOA 是否会引起支持细胞的自噬从而导致 BTB 损伤仍然是个谜。在这项研究中，我们发现 PFOA 可在体内和体外剂量依赖性地破坏支持细胞中的紧密连接（TJ）功能。此外，透射电子显微镜、Western blot 和免疫荧光分析的结果表明，PFOA 诱导睾丸支持细胞和 TM4 细胞中自噬体的积累。进一步的研究证实，自噬体的积累是由于自噬体和溶酶体融合受阻，导致自噬降解受阻，从而导致α-SNAP 表达下调。同时，也观察到 MMP9 在体内和体外的过表达。相反，在 TM4 细胞中过表达α-SNAP 可抑制 MMP9 的表达。总之，PFOA 通过下调支持细胞中α-SNAP 的表达水平来阻断自噬流，从而导致 MMP9 的积累，进而破坏 TJ 功能。这一发现为有效预防和治疗 PFOA 引起的雄性生殖毒性提供了线索。
