RESUMO
Dysfunction of the proximal tubule (PT) is associated with variable degrees of solute wasting and low-molecular-weight proteinuria. We measured metabolic consequences and adaptation mechanisms in a model of inherited PT disorders using PT cells of ClC-5-deficient (Clcn5Y/-) mice, a well-established model of Dent's disease. Compared to cells taken from control mice, those from the mutant mice had increased expression of markers of proliferation (Ki67, proliferative cell nuclear antigen (PCNA), and cyclin E) and oxidative scavengers (superoxide dismutase I and thioredoxin). Transcriptome and protein analyses showed fourfold induction of type III carbonic anhydrase in a kidney-specific manner in the knockout mice located in scattered PT cells. Kidney-specific carbonic anhydrase type III (CAIII) upregulation was confirmed in other mice lacking the multiligand receptor megalin and in a patient with Dent's disease due to an inactivating CLCN5 mutation. The type III enzyme was specifically detected in the urine of mice lacking ClC-5 or megalin, patients with Dent's disease, and in PT cell lines exposed to oxidative stress. Our study shows that lack of PT ClC-5 in mice and men is associated with CAIII induction, increased cell proliferation, and oxidative stress.
Assuntos
Anidrase Carbônica III/fisiologia , Canais de Cloreto/deficiência , Síndrome de Fanconi/patologia , Túbulos Renais Proximais/fisiologia , Animais , Anidrase Carbônica III/urina , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Knockout , Estresse OxidativoRESUMO
Understanding renal function requires one to integrate the structural complexity of kidney nephrons and the dynamic nature of their cellular processes. Multi-photon fluorescence microscopy is a state-of-the-art imaging technique for in vivo analysis of kidney tubules structure and function in real time. This study presents visual evidence for several levels of heterogeneity of proximal tubular endocytic uptake in the superficial renal mouse cortex and illustrates the potential of multi-photon microscopy for providing a comprehensive and dynamic portrayal of renal function.
