Transcription factor ZEB2 is essential for ureteral smooth muscle cell differentiation

Mowat-Wilson Syndrome (MWS) is an autosomal dominant genetic disorder caused by heterozygous mutations or deletions in the Zinc finger E-box-binding homeobox 2 (ZEB2) gene. Congenital anomalies of the kidney and urinary tract (CAKUT), including hydroureter and hydronephrosis, have been reported in patients with MWS. However, the role of the ZEB2 gene in urinary tract development and the cellular and molecular mechanisms underlying the CAKUT phenotypes in MWS remain unknown. In this study, we examined ZEB2 expression in the developing mouse ureter and generated Zeb2 ureteral mesenchyme-specific conditional knockout mice (Zeb2 cKO) by crossing Zeb2 floxed mice with Tbx18Cre+ mice. The urinary tract of Zeb2 cKO mice and their wild-type littermates was analyzed for morphological and histological changes. Our results show that ZEB2 is expressed in TBX18+ ureteral mesenchymal cells during mouse ureter development. Deleting Zeb2 in these cells caused hydroureter and hydronephrosis, indicating obstructive uropathy. Cellular and molecular marker analysis revealed that the TAGLN+ACTA2+ ureteral smooth muscle cell (SMC) layer was absent in Zeb2 cKO mice. In contrast, the tunica adventitia cell layer was significantly expanded compared to controls. At the molecular level, Zeb2 cKO mice had significantly decreased TBX18 expression but increased SOX9 expression in the developing ureter compared to wild-type controls. Our findings demonstrate that ZEB2 is crucial for normal ureteral SMC differentiation during ureter development. Additionally, our study suggests that MWS patients may have abnormal ureteral SMC development, which contributes to the abnormalities of the urinary tract.