Prenatal exposure to bisphenol AF induced male offspring reproductive dysfunction by triggering testicular innate and adaptive immune responses

Abstract

As an emerging endocrine-disrupting component with a chemical structure related to Bisphenol A (BPA), Bisphenol AF (BPAF) has become widely distributed in the environment and human surroundings. Although numerous studies have focused on its reproductive toxicity, the impact of prenatal BPAF exposure on the reproductive system of adult male offspring, particularly testicular morphology and function, as well as the underlying mechanisms, remains largely understudied. This study found prenatal BPAF exposure at a dose of 300 μg/kg b.w. induced a 32% loss of seminal vesicle weight, a 12% reduction in the anogenital distance index (AGI), and impairments to testicular morphology, such as a reduced diameter of seminiferous tubules and thickness of the seminiferous epithelium, as well as a more than 2 - fold decrease in testosterone level, and 41% and 19% reduction of sperm count and vitality, respectively, in the 10 week-old male offsprings. Testicular RNA-Seq data showed that 334 differential expressed genes (DEGs) were primarily involved in several immunological processes, including host defense response, innate and adaptive immune response, cellular response to interferon (IFN)-β and γ, antigen processing and presentation, regulation of T cell activation, etc. Importantly, our results revealed a pattern recognition receptor — absent in melanoma-2 (Aim2) was significantly increased in the testes of exposed males, thus triggering a testicular innate antiviral immunological response, leading to an increase of F4/80+ and CD11b+ macrophage. Subsequently, Aim2 activated the downstream signaling nuclear factor kappa-B (NF-κB), stimulated the transcription of IFN-β and -γ, and then induced cytokine production while upregulating MHC class II molecules to activate CD4+ and CD8+ Tcells, suggesting that an adaptive immune response was also elicited. The results demonstrated that prenatal BPAF exposure could provoke innate and adaptive immunological responses in the testes of adult males through the Aim2-NF-κB-IFNs signaling pathway. Our work provided insights into understanding the reproductive toxicity caused by BPAF and clarified the possible mechanisms, which offered a potential therapeutic target and treatment strategy for BPAF exposure-induced reproductive dysfunction.