Hydronephrosis with ureteritis developed in C57BL/6N mice carrying the congenic region derived from MRL/MpJ-type chromosome 11

Abnormal Morphology of Distal Tubular Epithelial Cells Is Regulated by Genetic Factors Derived from Mouse Chromosome 12

The distal tubule (DT) helps regulate blood pressure and electrolytes. We describe a novel, autosomal recessive, morphofunctional DT abnormality in inbred mice evident as columnar alternations and age-related cystic changes. This abnormality developed in both sexes of DBA/2Cr. Similar phenotypes were observed in A/J, C3H/He, DBA/1J, and FVB/N strains, but not in AKR/N, BALB/c, or C57BL/6N strains. In DBA/2Cr, abnormal DT localized to straight and convoluted segments and showed IL-36α DT injury marker expression. However, DT epithelial proliferation, examined by bromodeoxyuridine incorporation, was not remarkably altered with the progression of abnormality. Abnormal DT epithelial cells in DBA/2Cr displayed elongated primary cilia, loose intercellular adhesions, and numerous vesicles with altered localization of CD9, Na⁺/K⁺ATPase, and E-cadherin, indicating altered cell function, adhesion, and polarity. DBA/2Cr-type D12Mit182-D12Mit83 was identified as a candidate locus designated DBA/2 renal cyst (drecy). Within drecy, the gene regulated by estrogen in breast cancer protein (Greb1) transcript variant 2 was significantly up-regulated in DBA/2Cr kidney versus C57BL/6N. Greb1 localized to DT cytoplasm in C57BL/6 and to cytoplasm and nucleus in DBA/2Cr. Greb1-overexpressing M-1 kidney cells showed an altered epithelial-mesenchyme phenotype. B6.D2-(D12Mit182-D12Mit83) congenic mice carrying drecy did not show DT abnormalities, whereas DBA/2Cr × B6.D2-(D12Mit182-D12Mit83) mice did. Identification of this novel DT abnormality regulated by a DBA/2Cr mouse chromosome 12-derived locus and additional genetic factors improve the understanding of DT pathogenesis.