Increased NHE2 expression in rat intestinal epithelium during ontogeny is transcriptionally mediated

James F. Collins, Pawel R. Kiela, Hua Xu, Jiamin Zeng, Fayez K. Ghishan

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

We have previously described changes in intestinal brush-border membrane vesicle (BBMV) Na+/H+ exchange activity and characterized Na+/H+ exchanger (NHE3) expression during rat ontogeny. The current studies were designed to investigate developmental changes in NHE2 expression in rat intestine. In previous studies, pH-dependent uptake of Na+ in jejunal BBMV utilizing HOE-694 inhibition demonstrated that NHE2 functional protein levels were lowest in 2-wk-old rats, higher in 3-wk-old and adult rats, and highest in 6-wk-old rats [Collins et al. Am. J. Physiol. 273 (Cell Physiol. 42): C1937-C1946, 1997]. In the current investigation, Northern blot analyses showed that NHE2 mRNA levels in the jejunum were similar in 6-wk-old, adult, and 3-wk-old rats and three- to fivefold lower in 2-wk-old rats. In situ hybridization of 2- and 6-wk-old rat intestine with NHE2-specific probes confirmed Northern blot observations. Polyclonal antibodies were developed against an NHE2-specific peptide from amino acids 652-661. Western blots with NHE2 antiserum showed that the intensity of a specific 90-kDa band was lowest in 2-wk-old animals and four- to sixfold higher in 3- and 6-wk-old and adult animals. Immunohistochemical analysis showed specific staining of NHE2 antiserum to only the apical intestinal membrane. Furthermore, nuclear run- on analyses showed a 1.7-fold higher NHE2 transcription rate in 6-wk-old rats than in 2-wk-old rats. Overall, the current data suggest that increases in NHE2 expression upon weaning are mediated by increased gene transcription.

Original languageEnglish (US)
Pages (from-to)C1143-C1150
JournalAmerican Journal of Physiology - Cell Physiology
Volume275
Issue number4 44-4
StatePublished - Oct 1 1998

Keywords

  • Brush-border membrane
  • Jejuhum
  • Rat intestinal development
  • Sodium/hydrogen exchanger
  • Transcription rate analysis

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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