Gene expression changes upon the ablation of mesenchymal androgen receptor (AR) in the mouse mesonephroi
Wolffian duct maintenance and differentiation is predominantly driven by the androgen action, which is mediated by the androgen receptor (AR). It is well established that the mesenchyme indicates the fate and differentiation of epithelial cells. However, in vivo developmental requirement of mesenchymal AR in Wolffian duct development is still undefined. By designing a mesenchyme-specific Ar knockout (ARKO), we discovered that the loss of mesenchymal Ar led to the bilateral or unilateral degeneration of caudal Wolffian ducts and cystic formation at the cranial Wolffian ducts. Ex vivo culture of ARKO Wolffian ducts invariably resulted in bilateral defects, suggesting that some factor(s) originating from surrounding tissues in vivo might promote Wolffian duct survival and growth even in the absence of mesenchymal Ar. Mechanistically, we found cell proliferation was significantly reduced in both epithelial and mesenchymal compartments; but cell apoptosis was not affected. Transcriptomic analysis by RNA-seq revealed differentially expressed genes associated with morphological and cellular changes in ARKO male embryos (i.e. reduced cell proliferation and decreased number of epithelial cells). Mesenchymal differentiation into smooth muscle cells that are critical for morphogenesis was also impaired in ARKO male embryos. Taken together, our results demonstrate the crucial roles of the mesenchymal AR in Wolffian duct maintenance and morphogenesis in mice. Overall design: To investigate the function of mesenchymal AR in Wolffian duct development, we designed a tissue-specific ARKO model, Osr2-Cre; Ar-flox. In this model, we successfully ablated Ar in the mesenchyme of the Wolffian duct before sexual differentiation We prepared 3 ARKO and 3 control mesonephroi from mouse embryos at embryonic day E14.5. The mesonephroi used in this study did not include mesonephric tubule region. Tissues were snap frozen and then extracted for RNAs.