PFOA and PFOS impair human sperm capacitation by inducing mitochondrial-mediated apoptosis and ferroptosis

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), two predominant per- and polyfluoroalkyl substances, are ubiquitous environmental contaminants that have been implicated in male infertility. However, the effects and underlying mechanisms of these compounds during human sperm capacitation remain unclear. In this study, human spermatozoa were exposed to PFOA and PFOS during capacitation. Acrosome reaction and sperm viability were assessed by flow cytometry. Sperm motility and hyperactivation were assessed using computer-assisted sperm analysis. Proteomic and phosphoproteomic profiling was performed after exposure to PFOS or PFOA. Based on omics results, mitochondrial function, including mitochondrial membrane potential (Δψm) and mitochondrial permeability transition pore (MPTP) opening, was further evaluated. Antioxidant enzyme activities and non-enzymatic antioxidant levels were quantified, alongside biomarkers of apoptosis and ferroptosis. Our results demonstrated that PFOA and PFOS impaired hyperactivation and acrosome reaction while increasing sperm mortality. Proteomic and phosphoproteomic analyses revealed that PFOA and PFOS disrupted sperm capacitation through mitochondrial dysfunction and ATP dysregulation, ultimately promoting apoptosis and ferroptosis. Consistently, both compounds decreased Δψm, induced MPTP opening, and disrupted redox homeostasis, as evidenced by reduced antioxidant enzyme activities and GSH depletion. Mechanistically, PFOA and PFOS activated mitochondrial-mediated apoptosis, indicated by BAX upregulation, BCL2 downregulation, Caspase 3 activation, and PARP1 cleavage. Meanwhile, ferroptosis was triggered, as shown by increased intracellular iron and MDA accumulation, GPX4 downregulation, and ACSL4 upregulation. In conclusion, PFOA and PFOS impair human sperm capacitation by inducing mitochondrial-mediated apoptosis and ferroptosis, thereby compromising fertilization potential. These findings provide novel mechanistic insights into PFAS-induced male reproductive toxicity.