Regulation of Extracellular Fluid Volume and Blood Pressure by Pendrin

Cellular Physiology and Biochemistry

关键词: Intercalated cells;    NDCBE;    AQP5;    Distal nephron;    Cell volume;    ATP;   

DOI  :  10.1159/000335116

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Na⁺ is commonly designed as the culprit of salt-sensitive hypertension but several studies suggest that abnormal Cl^- transport is in fact the triggering mechanism. This review focuses on the regulation of blood pressure (BP) by pendrin, an apical Cl^-/HCO₃^- exchanger which mediates HCO₃^- secretion and transcellular Cl^- transport in type B intercalated cells (B-ICs) of the distal nephron. Studies in mice showed that it is required not only for acid-base regulation but also for BP regulation as pendrin knock-out mice develop hypotension when submitted to NaCl restriction and are resistant to aldosterone-induced hypertension. Pendrin contributes to these processes by two mechanisms. First, pendrin-mediated Cl^- transport is coupled with Na⁺ reabsorption by the Na⁺-dependent Cl^-/HCO₃^- exchanger NDCBE to mediate NaCl reabsorption in B-ICs. Second, pendrin activity regulates Na⁺ reabsorption by the adjacent principal cells, possibly by interaction with the ATP-mediated paracrine signalling recently identified between ICs and principal cells. Interestingly, the water channel AQP5 was recently found to be expressed at the apical side of B-ICs, in the absence of a basolateral water channel, and pendrin and AQP5 membrane expressions are both inhibited by K⁺ depletion, suggesting that pendrin and AQP5 could cooperate to regulate cell volume, a potent stimulus of ATP release.

【 授权许可】

CC BY-NC-ND