Blog
About

0
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      SLC26A6 and SLC26A7 Anion Exchangers Have a Distinct Distribution in Human Kidney

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background: The anion transporters SLC26A6 (PAT1) and SLC26A7, transporting at least chloride, oxalate, sulfate and bicarbonate, show a distinct expression and function in different mammalian species. They are expressed in kidney, but their exact localization in human kidney has not been studied. We therefore examined SLC26A6 and A7 expression in human kidneys. Methods: The localization of SLC26A6 and A7 in different segments of human nephrons was studied by RT-PCR and immunohistochemistry by comparing to the tubular markers PNRA, CD10, Tamm-Horsfall antigen, high molecular weight cytokeratin, CK7, AQP2 and H<sup>+</sup>V-ATPase. Results: In human kidney, SLC26A6 is expressed in distal segments of proximal tubules, parts of the thin and thick ascending limbs of Henle’s loops, macula densa, distal convoluted tubules and a subpopulation of intercalated cells of collecting ducts. SLC26A7 is expressed in extraglomerular mesangial cells and a subpopulation of intercalated cells of collecting ducts. Conclusion: Our results show that in human kidney SLC26A6 and A7 have a distinct, partially overlapping expression in distal segments of nephrons. The distribution partly differs from that found previously in rodent kidneys.

          Related collections

          Most cited references 20

          • Record: found
          • Abstract: found
          • Article: not found

          Renal vacuolar H+-ATPase.

          Vacuolar H(+)-ATPases are ubiquitous multisubunit complexes mediating the ATP-dependent transport of protons. In addition to their role in acidifying the lumen of various intracellular organelles, vacuolar H(+)-ATPases fulfill special tasks in the kidney. Vacuolar H(+)-ATPases are expressed in the plasma membrane in the kidney almost along the entire length of the nephron with apical and/or basolateral localization patterns. In the proximal tubule, a high number of vacuolar H(+)-ATPases are also found in endosomes, which are acidified by the pump. In addition, vacuolar H(+)-ATPases contribute to proximal tubular bicarbonate reabsorption. The importance in final urinary acidification along the collecting system is highlighted by monogenic defects in two subunits (ATP6V0A4, ATP6V1B1) of the vacuolar H(+)-ATPase in patients with distal renal tubular acidosis. The activity of vacuolar H(+)-ATPases is tightly regulated by a variety of factors such as the acid-base or electrolyte status. This regulation is at least in part mediated by various hormones and protein-protein interactions between regulatory proteins and multiple subunits of the pump.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Functional characterization of three novel tissue-specific anion exchangers SLC26A7, -A8, and -A9.

            A second distinct family of anion exchangers, SLC26, in addition to the classical SLC4 (or anion exchanger) family, has recently been delineated. Particular interest in this gene family is stimulated by the fact that the SLC26A2, SLC26A3, and SLC26A4 genes have been recognized as the disease genes mutated in diastrophic dysplasia, congenital chloride diarrhea, and Pendred syndrome, respectively. We report the expansion of the SLC26 gene family by characterizing three novel tissue-specific members, named SLC26A7, SLC26A8, and SLC26A9, on chromosomes 8, 6, and 1, respectively. The SLC26A7-A9 proteins are structurally very similar at the amino acid level to the previous family members and show tissue-specific expression in kidney, testis, and lung, respectively. More detailed characterization by immunohistochemistry and/or in situ hybridization localized SLC26A7 to distal segments of nephrons, SLC26A8 to developing spermatocytes, and SLC26A9 to the lumenal side of the bronchiolar and alveolar epithelium of lung. Expression of SLC26A7-A9 proteins in Xenopus oocytes demonstrated chloride, sulfate, and oxalate transport activity, suggesting that they encode functional anion exchangers. The functional characterization of the novel tissue-specific members may provide new insights to anion transport physiology in different parts of body.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Identification of a chloride-formate exchanger expressed on the brush border membrane of renal proximal tubule cells.

              A key function of the proximal tubule is retrieval of most of the vast quantities of NaCl and water filtered by the kidney. Physiological studies using brush border vesicles and perfused tubules have indicated that a major fraction of Cl(-) reabsorption across the apical membrane of proximal tubule cells occurs via Cl(-)-formate exchange. The molecular identity of the transporter responsible for renal brush border Cl(-)-formate exchange has yet to be elucidated. As a strategy to identify one or more anion exchangers responsible for mediating Cl(-) reabsorption in the proximal tubule, we screened the expressed sequence tag database for homologs of pendrin, a transporter previously shown to mediate Cl(-)-formate exchange. We now report the cDNA cloning of CFEX, a mouse pendrin homolog with expression in the kidney by Northern analysis. Sequence analysis indicated that CFEX very likely represents the mouse ortholog of human SLC26A6. Immunolocalization studies detected expression of CFEX, but not pendrin, on the brush border membrane of proximal tubule cells. Functional expression studies in Xenopus oocytes demonstrated that CFEX mediates Cl(-)-formate exchange. Taken together, these observations identify CFEX as a prime candidate to mediate Cl(-)-formate exchange in the proximal tubule and thereby to contribute importantly to renal NaCl reabsorption. Given its wide tissue distribution, CFEX also may contribute to transcellular Cl(-) transport in additional epithelia such as the pancreas and contribute to transmembrane Cl(-) transport in nonepithelial tissues such as the heart.
                Bookmark

                Author and article information

                Journal
                NEE
                Nephron Exp Nephrol
                10.1159/issn.1660-2129
                Cardiorenal Medicine
                S. Karger AG
                1660-2129
                2005
                October 2005
                15 June 2005
                : 101
                : 2
                : e50-e58
                Affiliations
                aDepartment of Medical Genetics, University of Helsinki; bDepartment of Urology, Helsinki University Central Hospital, Helsinki; cDepartment of Pathology, Helsinki University Central Hospital/Peijas Hospital and HUSLAB, Vantaa; dInstitute of Biomedicine, Developmental Biology, University of Helsinki, and HUCH Laboratory Diagnostics, Helsinki University Hospital; eDepartment of Pathology, Haartman Institute and Helsinki University Central Hospital, University of Helsinki, Helsinki Finland, and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, Calif., USA; fDepartment of Biosciences at Novum, Karolinska Institutet, Stockholm, Sweden
                Article
                86345 Nephron Exp Nephrol 2005;101:e50–e58
                10.1159/000086345
                15956810
                © 2005 S. Karger AG, Basel

                Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

                Page count
                Figures: 5, References: 42, Pages: 1
                Product
                Self URI (application/pdf): https://www.karger.com/Article/Pdf/86345
                Categories
                Original Paper

                Comments

                Comment on this article