Expression of an Anion Exchanger Pendrin in Human Kidney

Kim, Wan Young; Kim, Gheun Ho; Han, Ki Hwan; Song, Hyun Kuk; Han, Jin Suk; Kim, Jin

Abstract

It has been reported that new apical anion exchanger perndrin, encoded by the pendred syndrome (PDS/pds, Slc26A4) gene, was expressed in the AE1-negative intercalated cells of rat and mouse kidneys. The purpose of this study was performed that expression of pendrin in the subtypes of intercalated cells in human kidney. The normal human renal tissues obtained from nephrotomized kidneys for renal cell carcinoma were fixed in periodate-lysine-paraformalde-hyde, and processed for immunohistochemistry. Subtypes of intercalated cells were identified by using antibodies for H(+)-ATPase and AE1, and connecting tubule cells and principal cells of collecting duct were identified using antibodies for calbindin D28K and AQP2, respectively. In human kidney, pendrin was expressed in the apical domain of AE1-negative intercalated cells including type B cells with diffuse and/or basolateal H(+)-ATPase, non A-non B (non -A/B) type intercalated cells with apical H(+)-ATPase and bipolar type of intercalated cells with apical and basolateral H(+)-ATPase. The AQP2-positive principal cells of cortical collecting duct were also had apical pendrin immunoreactivity. However, there was no pendrin immunoreactivity in AE1-positive type A intercalated cells, calbindin D28K-positive connecting tubule cells, and AQP2-positive medullary collecting duct. These results suggest that pendrin is an apical anion exchanger not only in the AE1-negative intercalated cells (type B, non-A/B and bipolar cells) but also in the principal cells of cortical collecting duct, and has an essential role in HCO3-secretion in human kidney.