| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Medicine, University of Cincinnati, Cincinnati, OH, USA
* To whom correspondence should be addressed. E-mail: Manoocher.Soleimani{at}uc.edu.
Bicarbonate secretion by gastric mucous cells is essential for protection against acid injury and peptic ulcer. Here we report the identification of an apical bicarbonate transporter in gastric surface epithelial cells. Northern hybridization and RT-PCR demonstrate the expression of this transporter, also known as SLC26A9, in mouse and rat stomach and trachea (but not kidney). In situ hybridization in mouse stomach showed abundant expression of SLC26A9 in surface epithelial cells with apical localization on immunofluorescence labeling. Functional studies in HEK 293 cells demonstrated that SLC26A9 mediates Cl-/HCO3- exchange and is also capable of transporting Cl-independent bicarbonate extrusion. Unlike other anion exchangers or transport proteins reported to date, SLC26A9 activity is inhibited by NH4+. The inhibitory effect of NH4+ on gastric bicarbonate secretion was also indicated by a reduced gastric juxtamucousal pH in rat stomach in vivo. This is the first report on the inhibition of bicarbonate transport in vitro and the reduction in juxtamucosal pH in stomach in vivo by NH4+. Given its critical localization on apical membrane of surface epithelial cells, its ability to transport bicarbonate and inhibition by NH4+ we propose that SLC26A9 mediates bicarbonate secretion in surface epithelial cells and is essential for protection against acid injury in the stomach. Disease states that are associated with increased NH3/NH4+ generation (such as H. Pylori) may impair gastric bicarbonate secretion and therefore predispose to peptic ulcer by inhibiting SLC26A9.
This article has been cited by other articles:
|
|
 |
|
  J. Xu, P. Song, S. Nakamura, M. Miller, S. Barone, S. L. Alper, B. Riederer, J. Bonhagen, L. J. Arend, H. Amlal, et al. Deletion of the Chloride Transporter Slc26a7 Causes Distal Renal Tubular Acidosis and Impairs Gastric Acid Secretion J. Biol. Chem., October 23, 2009; 284(43): 29470 - 29479. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.-H. Chang, C. Plata, A. Sindic, W. K. Ranatunga, A.-P. Chen, K. Zandi-Nejad, K. W. Chan, J. Thompson, D. B. Mount, and M. F. Romero Slc26a9 Is Inhibited by the R-region of the Cystic Fibrosis Transmembrane Conductance Regulator via the STAS Domain J. Biol. Chem., October 9, 2009; 284(41): 28306 - 28318. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Ohana, D. Yang, N. Shcheynikov, and S. Muallem Diverse transport modes by the solute carrier 26 family of anion transporters J. Physiol., May 15, 2009; 587(10): 2179 - 2185. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. A. Bertrand, R. Zhang, J. M. Pilewski, and R. A. Frizzell SLC26A9 is a constitutively active, CFTR-regulated anion conductance in human bronchial epithelia J. Gen. Physiol., April 1, 2009; 133(4): 421 - 438. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. R. Dorwart, N. Shcheynikov, D. Yang, and S. Muallem The Solute Carrier 26 Family of Proteins in Epithelial Ion Transport Physiology, April 1, 2008; 23(2): 104 - 114. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Akiba, M. Mizumori, P. H. Guth, E. Engel, and J. D. Kaunitz Duodenal brush border intestinal alkaline phosphatase activity affects bicarbonate secretion in rats Am J Physiol Gastrointest Liver Physiol, December 1, 2007; 293(6): G1223 - G1233. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Dorwart, N. Shcheynikov, Y. Wang, S. Stippec, and S. Muallem SLC26A9 is a Cl channel regulated by the WNK kinases J. Physiol., October 1, 2007; 584(1): 333 - 345. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. T. Nickell, N. K. Kleene, and S. J. Kleene Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium J. Physiol., September 15, 2007; 583(3): 1005 - 1020. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Ishiguro, W. Namkung, A. Yamamoto, Z. Wang, R. T. Worrell, J. Xu, M. G. Lee, and M. Soleimani Effect of Slc26a6 deletion on apical Cl-/HCO3- exchanger activity and cAMP-stimulated bicarbonate secretion in pancreatic duct Am J Physiol Gastrointest Liver Physiol, January 1, 2007; 292(1): G447 - G455. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Henriksnas, M. Phillipson, M. Storm, L. Engstrand, M. Soleimani, and L. Holm Impaired mucus-bicarbonate barrier in Helicobacter pylori-infected mice Am J Physiol Gastrointest Liver Physiol, September 1, 2006; 291(3): G396 - G403. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Petrovic, H. Amlal, X. Sun, F. Karet, S. Barone, and M. Soleimani Vasopressin induces expression of the Cl-/HCO3- exchanger SLC26A7 in kidney medullary collecting ducts of Brattleboro rats Am J Physiol Renal Physiol, May 1, 2006; 290(5): F1194 - F1201. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Shcheynikov, Y. Wang, M. Park, S. B.H. Ko, M. Dorwart, S. Naruse, P. J. Thomas, and S. Muallem Coupling Modes and Stoichiometry of Cl-/HCO3- Exchange by slc26a3 and slc26a6 J. Gen. Physiol., April 24, 2006; 127(5): 511 - 524. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Xu, R. T. Worrell, H. C. Li, S. L. Barone, S. Petrovic, H. Amlal, and M. Soleimani Chloride/Bicarbonate Exchanger SLC26A7 Is Localized in Endosomes in Medullary Collecting Duct Cells and Is Targeted to the Basolateral Membrane in Hypertonicity and Potassium Depletion J. Am. Soc. Nephrol., April 1, 2006; 17(4): 956 - 967. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. T. Worrell, A. Best, O. R. Crawford, J. Xu, M. Soleimani, and J. B. Matthews Apical ammonium inhibition of cAMP-stimulated secretion in T84 cells is bicarbonate dependent Am J Physiol Gastrointest Liver Physiol, October 1, 2005; 289(4): G768 - G778. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
