Impaired gastric acid secretion in mice with a targeted disruption of the NHE4 Na+/H+ exchanger

Lara R. Gawenis, Jeannette M. Greeb, Vikram Prasad, Christina Grisham, L. Philip Sanford, Thomas Doetschman, Anastasia Andringa, Marian L. Miller, Gary E. Shull

Research output: Contribution to journalArticlepeer-review

82 Scopus citations

Abstract

The NHE4 Na+/H+ exchanger is abundantly expressed on the basolateral membrane of gastric parietal cells. To test the hypothesis that it is required for normal acid secretion, NHE4-null mutant (NHE4-/-) mice were prepared by targeted disruption of the NHE4 (Slc9a4) gene. NHE4 -/- mice survived and appeared outwardly normal. Analysis of stomach contents revealed that NHE4-/- mice were hypochlorhydric. The reduction in acid secretion was similar in 18-day-old, 9-week-old, and 6-month-old mice, indicating that the hypochlorhydria phenotype did not progress over time, as was observed in mice lacking the NHE2 Na+/H + exchanger. Histological abnormalities were observed in the gastric mucosa of 9-week-old NHE4-/- mice, including sharply reduced numbers of parietal cells, a loss of mature chief cells, increased numbers of mucous and undifferentiated cells, and an increase in the number of necrotic and apoptotic cells. NHE4-/- parietal cells exhibited limited development of canalicular membranes and a virtual absence of tubulovesicles, and some of the microvilli had centrally bundled actin. We conclude that NHE4, which may normally be coupled with the AE2 Cl-/HCO3- exchanger, is important for normal levels of gastric acid secretion, gastric epithelial cell differentiation, and development of secretory canalicular and tubulovesicular membranes.

Original languageEnglish (US)
Pages (from-to)12781-12789
Number of pages9
JournalJournal of Biological Chemistry
Volume280
Issue number13
DOIs
StatePublished - Apr 1 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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