Mesenchymal actomyosin contractility is required for androgen-driven urethral masculinization in mice

Abstract

The morphogenesis of mammalian embryonic external genitalia (eExG) shows dynamic differences between males and females. In genotypic males, eExG are masculinized in response to androgen signaling. Disruption of this process can give rise to multiple male reproductive organ defects. Currently, mechanisms of androgen-driven sexually dimorphic organogenesis are still unclear. We show here that mesenchymal-derived actomyosin contractility, by MYH10, is essential for the masculinization of mouse eExG. MYH10 is expressed prominently in the bilateral mesenchyme of male eExG. Androgen induces MYH10 protein expression and actomyosin contractility in the bilateral mesenchyme. Inhibition of actomyosin contractility through blebbistatin treatment and mesenchymal genetic deletion induced defective urethral masculinization with reduced mesenchymal condensation. We also suggest that actomyosin contractility regulates androgen-dependent mesenchymal directional cell migration to form the condensation in the bilateral mesenchyme leading to changes in urethral plate shape to accomplish urethral masculinization. Thus, mesenchymal-derived actomyosin contractility is indispensable for androgen-driven urethral masculinization.

Stage‐dependent function of Wnt5a during male external genitalia development

“…16 In order to further elucidate the function of Wnt5a, we analyzed mesenchymal-specific conditional mutant mice using a Sall1-Cre driver mouse line at E18.5. 11 We deleted Wnt5a at two different timepoints corresponding to early (E10.5) and late (E13.5) GT outgrowth, 33 observing consistent phenotypes. ExG hypoplasia resulted from the deletion of Wnt5a at E10.5…”

“…Cells of the bi-Ms undergo directional cell migration during the formation of the male-type urethral tube. 10,11 During directed cell migration, cells are polarized and possess the requisite machinery to produce the force required for movement. 34 WNT5A binds to ROR2, an orphan receptor from the Ror family of receptor tyrosine kinases, to activate the non-canonical PCP signaling pathway.…”

“…Male bi-Ms cells directionally migrate towards the urethral epithelium in an androgen-dependent manner during urethral tube formation. 10,11 It is generally believed that cell movement and cell polarity are required for directed cell migration. 34 Wnt5a is known to be a key player in the regulation of cell polarity.…”

“…38 In fact, cell contractility is a requirement for androgen-induced urethral tube formation. 11 To investigate whether Wnt5a facilitates mesenchymal cell migration through regulating cell contractility, we analyzed the level of pMLC in the bi-Ms of the Wnt5a cKO and observed that the level of pMLC was dramatically reduced in the Wnt5a cKO compared to the control (Figure 4(A,B)).…”

3D reconstruction and histopathological analyses on murine corporal body

“…Paraffin sections were also prepared for staining. The detailed protocols were previously described 35 . For primary antibody staining, the following antibodies were utilized: anti‐CD31 (1/200, AF3628, AB_2161028, R&D systems), anti‐ACTA2 (1/1000, U 7033, DAKO), anti‐NG2 (1/100, AB5320, AB_11213678, Millipore), anti‐SOX9 (1/1000, AB5535, Millipore), and anti‐RBPJK (1/300, 2ZRBP2, Cosmo Bio).…”