Endocrine disruptors and male infertility: multi-omics identification of key genes in non-obstructive azoospermia

Environmental endocrine-disrupting chemicals (EDCs) are increasingly implicated in male infertility, yet the gene-level mechanisms by which EDCs contribute to non-obstructive azoospermia (NOA) remain unclear. This study aimed to identify EDC-related genes that are causally linked to NOA and uncover their potential roles in reproductive dysfunction.

We integrated transcriptomic analysis of GEO datasets, EDC-associated gene data from the Comparative Toxicogenomics Database (CTD), and Mendelian randomization (MR) to prioritize candidate genes with causal relevance to male infertility. Phenome-wide association study (PheWAS) was conducted to assess systemic effects. EDC-gene interactions were visualized, and single-cell RNA sequencing (scRNA-seq) was used to validate cell-type-specific gene expression in the testis.

A total of 136 genes were identified at the intersection of differentially expressed genes in NOA and EDC-related genes. MR analysis highlighted PPP6R1 and AP1M2 as causally linked to male infertility. PheWAS revealed a significant association between PPP6R1 and cardiovascular traits (p < 1 × 10^-6), suggesting pleiotropic effects. Interaction analysis identified 26 EDCs targeting these genes, including thiram, bisphenol A, and sodium arsenite. The scRNA-seq confirmed downregulation of both genes in germ cells of NOA patients.

Our multi-omics approach suggests a potential EDC-gene-NOA axis, identifying PPP6R1 and AP1M2 as candidate genes whose expression may be influenced by environmental exposure in the context of male infertility. These findings deepen mechanistic understanding of NOA pathogenesis and support future research into environmental and molecular targets for diagnosis and prevention.