Characterization of a new Dent Disease mouse model carrying a pathogenic mutation of ClC‐5

Abstract

Dent Disease is a rare X‐linked inherited renal proximal disorder characterized by low molecular weight (LMW) proteinuria, hypercalciuria, kidney stones and progressive renal failure. Inactivating mutations of the CLCN5 gene encoding the 2Cl−/H+ exchanger ClC‐5 have been identified in approximately two‐thirds of patients with Dent Disease. ClC‐5 is predominantly expressed in early endosomes of proximal tubules where it optimizes the function of a vacuolar H+ pump to ensure an efficient endocytosis of LMW proteins.We have previously investigated the functional consequences of CLCN5 mutations in heterologous expression systems and shown that 60 % of the mutations lead to a defect in protein folding and processing. As a consequence, the misfolded ClC‐5 are retained within the endoplasmic reticulum (ER) where they could induce ER stress response. Such ER stress might in turn induce oxidative stress in proximal tubule cells. To investigate the consequences of intracellular retention of a misfolded ClC‐5, we created a mouse model carrying the N340K pathogenic mutation.ClC‐5 expression and localization in WT and N340K male mice were studied by Western blot and on kidney sections by immunofluorescence. Daily food, water intake, body weight and urine excretion data were collected in metabolic cages for N340K and WT mice. Urine as well as blood samples were analysed for ions, protein, glucose and creatinine to detect kidney dysfunction as observed in patients with Dent Disease.Mice carrying the N340K mutation displayed ClC‐5 intracellular retention in proximal tubules cells. They showed an increased urinary calcium and glucose excretion and a decreased urinary pH. They also had a severe LMW proteinuria, recapitulating common features of Dent Disease.The present study validates a new Dent Disease mouse model carrying a pathogenic Clcn5 mutation retained in the ER. The potential link between ClC‐5 retention in the ER, ER stress and oxidative stress responses has yet to be demonstrated.Support or Funding InformationPrix “Jeune Chercheur”, Fondation du Rein 2017This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.