Perfluorooctane sulfonic acid impairs spermatogenesis via the liver-gut microbiota-testis axis: a central role of chenodeoxycholic acid metabolism

Perfluorooctane sulfonic acid (PFOS) as a global contaminant is ubiquitously presented in the environmental media and human body. The association between PFOS exposure and reduced male fertility has been recently discovered. However, the relevant mechanism remains unexplored. Our study aimed to investigate the effect and mechanism of PFOS exposure on male reproductive function. In a murine PFOS exposure model, single-nucleus transcriptome sequencing was performed to delineate the transcriptomic landscape of mouse testes at the single-cell resolution. We examined the serum metabolomic profile and conducted in-depth analysis of hepatic transcriptome datasets to explore the metabolic connections between liver and testis under PFOS exposure. Through integrating chenodeoxycholic acid intervention, fecal microbiota transplantation (FMT), metagenomic sequencing, testicular metabolome, Ligilactobacillus murinus (L. murinus) metabolome, and administration of L. murinus, we confirmed the role of the liver-gut microbiota-testis axis and screened the critical gut microbiota involved in PFOS-mediated spermatogenic disorders. The results showed that PFOS exposure led to spermatogenic arrest and abnormal spermatogenic microenvironment in the mouse testis. The PFOS-repressed hepatic chenodeoxycholic acid (CDCA) synthesis contributed to the reduced serum/testicular levels of essential fatty acid (linoleic acid) and lipid-soluble vitamins (retinol, vitamin D3), which was responsible for the spermatogenic arrest. Beyond this, PFOS-mediated impaired CDCA production decreased the abundance of gut L. murinus, which affected spermatogenesis through the potential involvement of aspartic acid metabolism. For the first time to our knowledge, we comprehensively assessed the effects of PFOS exposure on the spermatogenic process and elucidated the unrecognized role of liver-gut microbiota-testis axis in PFOS-induced abnormal spermatogenesis. The unveiled organ crosstalks provide new insights into the metabolism-disrupting properties, hepatotoxicity, and reproductive toxicity of PFOS, which may facilitate the development of molecule-, metabolite-, and microbe-based strategies for PFOS-induced metabolic diseases and reproductive disorders.