FOXD1+ cell–derived stromal cells give rise to pericytes and fibroblasts that support the kidney vasculature and interstitium but are also major precursors of myofibroblasts. ZEB2 is a SMAD-interacting transcription factor that is expressed in developing kidney stromal progenitors. Here we show that Zeb2 is essential for normal FOXD1+ stromal progenitor development. Specific conditional knockout of mouse Zeb2 in FOXD1+ stromal progenitors (Zeb2 cKO) leads to abnormal interstitial stromal cell development, differentiation, and kidney fibrosis. Immunofluorescent staining analyses revealed abnormal expression of interstitial stromal cell markers MEIS1/2/3, CDKN1C, and CSPG4 (NG2) in newborn and 3-week-old Zeb2-cKO mouse kidneys. Zeb2-deficient FOXD1+ stromal progenitors also took on a myofibroblast fate that led to kidney fibrosis and kidney failure. Cell marker studies further confirmed that these myofibroblasts expressed pericyte and resident fibroblast markers, including PDGFRβ, CSPG4, desmin, GLI1, and NT5E. Notably, increased interstitial collagen deposition associated with loss of Zeb2 in FOXD1+ stromal progenitors was accompanied by increased expression of activated SMAD1/5/8, SMAD2/3, SMAD4, and AXIN2. Thus, our study identifies a key role of ZEB2 in maintaining the cell fate of FOXD1+ stromal progenitors during kidney development, whereas loss of ZEB2 leads to differentiation of FOXD1+ stromal progenitors into myofibroblasts and kidney fibrosis.
Sudhir Kumar, Xueping Fan, Hila Milo Rasouly, Richa Sharma, David J. Salant, Weining Lu