ERα maintains the junctional function of testicular Sertoli cells by activating the PKR pathway via upregulation of c-Fos.

Estrogen receptor α (ERα) is a ligand-regulated transcription factor essential for spermatogenesis and Sertoli cell junctional function. However, the molecular mechanisms underlying its regulatory role remain incompletely defined. In this study, we investigated the role of ERα in maintaining Sertoli cell barrier integrity using both in vivo and in vitro models. ERα inhibition impaired spermatogenesis in vivo, as evidenced by reduced sperm viability and disrupted seminiferous tubule architecture. In both models, ERα inhibition compromised blood-testis barrier (BTB) integrity, accompanied by decreased expression of junctional proteins including Zonula occludens-1 (ZO-1), Occludin, β-Catenin, and Connexin-43 (Cx43). Mechanistically, RNA sequencing identified the Protein Kinase R (PKR) signaling pathway as a downstream effector of ERα. Functional validation further confirmed that ERα maintains Sertoli cell barrier function through activation of the PKR pathway. In addition, chromatin immunoprecipitation assays demonstrated that ERα directly binds to the c-Fos promoter to regulate its transcription, leading to increased c-Fos expression and subsequent activation of PKR signaling. These findings offer novel insights into potential therapeutic targets for testicular dysfunction.