Immunocytochemical localization of pendrin in intercalated cell subtypes in rat and mouse kidney

Abstract

Recent studies have demonstrated that a novel anion exchanger, pendrin, is expressed in the apical domain of type B intercalated cells in the mammalian collecting duct. The purpose of this study was 1) to determine the expression and distribution of pendrin along the collecting duct and connecting tubule of mouse and rat kidney and establish whether pendrin is expressed in the non-A-non-B intercalated cells and 2) to determine the intracellular localization of pendrin in the different populations of intercalated cells by immunoelectron microscopy. A peptide-derived affinity-purified antibody was generated that specifically recognized pendrin in immunoblots of rat and mouse kidney. Immunohistochemistry and confocal laser scanning microscopy demonstrated the presence of pendrin in apical domains of all type B intercalated cells in mouse and rat connecting tubule and collecting duct. In addition, strong pendrin immunostaining was observed in non-A-non-B intercalated cells. There was no labeling of type A intercalated cells. Immunoelectron microscopy demonstrated that pendrin was located in the apical plasma membrane and intracellular vesicles of both type B intercalated cells and non-A-non-B cells; the latter was identified by the presence of H(+)-ATPase in the apical plasma membrane. The results of this study demonstrate that both pendrin and H(+)-ATPase are expressed in the apical plasma membrane of non-A-non-B intercalated cells, suggesting that these cells are capable of both HCO and proton secretion. Furthermore, the presence of pendrin in both the apical plasma membrane and the apical intracellular vesicles of type B and non-A-non-B intercalated cells suggests that HCO secretion may be regulated by trafficking of pendrin between the two membrane compartments.

Immunolocalization of AQP-5 in rat parotid and submandibular salivary glands after stimulation or inhibition of secretion in vivo

“…The sections were then rinsed in PBS and mounted with glycerol supplemented with antifading reagent (N-propyl gallate). The microscopy was carried out using a Leica laser confocal microscope (8,17). Immunolabeling controls were performed using antibodies preadsorbed with the immunizing peptide (data not shown).…”

Pendrin Regulation in Mouse Kidney Primarily Is Chloride-Dependent

“…Cl Ϫ transport does not occur through principal cells but rather through the paracellular pathway or through the intercalated cells (11). In the B and non-A non-B type intercalated cells, pendrin, an apical anion exchanger (12)(13)(14), is believed to play a key role in BP regulation, most likely by controlling distal nephron chloride reabsorption (15,16). Pendrin is upregulated by the injection of deoxycorticosterone pivalate, a pharmacologic analogue of aldosterone (16).…”

NaCl Restriction Upregulates Renal Slc26a4 Through Subcellular Redistribution

“…2,3,6 Slc26a4 localizes to the apical plasma membrane and apical cytoplasmic vesicles of type B and non-A, non-B intercalated cells within the cortical collecting duct (CCD), the connecting tubule (CNT), the initial collecting tubule (iCT), and the distal convoluted tubule (DCT). 5,7,8 Because Slc26a4 transports HCO 3 Ϫ and participates in bicarbonate secretion by type B intercalated cells, 5,9 previous studies have focused on the role of Slc26a4 in acid-base balance and have shown that Slc26a4 is upregulated in models of metabolic alkalosis. With administration of aldosterone analogues (deoxycorticosterone [DOCP]), Slc26a4 expression is upregulated in tandem with upregulation of apical Cl Ϫ /HCO 3 Ϫ exchange, which increases HCO 3 Ϫ secretion.…”

“…7,8,15 We have made 2 observations that suggest that the increase in Cl Ϫ absorption by the CCD and CNT following administration of aldosterone analogues is Slc26a4-dependent. 11 First, Slc26a4 is greatly upregulated with DOCP.…”