Crucial roles of mesenchymal Gata2 in murine epididymal development
Androgens drive the morphogenesis and differentiation of the Wolffian duct (WD) into the epididymis, an essential organ for male reproduction, by binding to the androgen receptor (AR). However, it remains unclear whether other transcriptional programs operate beyond the central androgen/AR signaling in promoting WD development. We discovered that mesenchyme-specific deletion of the transcription factor Gata2 resulted in defective epididymal coiling in the corpus and caudal regions. The defective coiling in the absence of mesenchymal Gata2 did not result from androgen production deficiency, as there were no abnormalities in androgen production or AR/Ar expression, and dihydrotestosterone supplementation did not restore epididymal coiling in cultured WDs. Instead, Gata2 deletion might disrupt mesenchymal identity, as indicated by the significant downregulation of Itga4, an mesenchymal epididymal marker. This loss of mesenchymal identity was accompanied by reduced expression of the mesenchyme-derived morphogen Inhba and decreased epithelial proliferation, both of which are critical for proper epididymal coiling. The developmental defects persisted into adulthood, with the uncoiled corpus and caudal epididymis exhibiting abnormal epithelial morphology and luminal environments, ultimately creating conditions unsuitable for sperm storage and leading to infertility. Notably, in adult knockouts, the epididymal epithelium aberrantly expressed aSMA, further indicating a failure to properly establish epithelial differentiation. Our findings reveal an androgen-independent role for mesenchymal GATA2 in maintaining mesenchymal identity during epididymal development, highlighting the importance of proper fetal mesenchymal specification for male reproductive function. Overall design: To explore the functional role of mesenchymal Gata2 in Wolffian duct development, we generated a tissue-specific conditional knockout model by crossing Gata2-flox mice with Osr2-Cre. We prepared 3 Gata2cKO and 3 control mesonephroi from mouse embryos at embryonic day (E) 16.5. The mesonephroi used in this study included mesonephric tubule region. Embryonic day (E16.5) mesonephroi were snap frozen and then extracted for RNA.