Expression of Na+/H+ exchanger isoforms in normal human nasal epithelial cells and functional activity of Na+/H + exchanger 1 in intracellular pH regulation

Ji Hyun Shin, Wan Namkung, Chang Hoon Kim, Jae Young Choi, Jong Bum Yoo, Kyung Dong Lee, Jeung Gweon Lee, Min Goo Lee, Joo Heon Yoon

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Conclusions. Both the mRNA and protein of NHE1, -2 and -3 were expressed in NHNE cells. NHE1 is a major NHE isoform which is expressed in the basolateral membranes of NHNE cells. Objective. Na+/H+ exchangers are ubiquitous plasma membrane transport proteins implicated in the maintenance of intracellular pH. The aim of this study was to examine the expression of Na +/H+ exchangers as a function of the differentiation of normal human nasal epithelial (NHNE) cells. In addition, we investigated the functional activity of the Na+/H+ exchanger 1 (NHE1) in basolateral membranes. Material and methods. Cultured passage-2 NHNE cells were used. RNA and histological samples were collected on the day of confluence and on the 7th, 14th and 28th days after confluence in order to determine the effects of time. Cell lysates were collected on the day of confluence to investigate the presence of the proteins. Reverse transcriptase polymerase chain reaction and Western blotting were performed to investigate the presence of mRNA and protein, respectively. The functional activity of NHE1 was examined using 3-methylsulfonyl-4-piperidinobenzoyl guanidine methanesulfonate (HOE694), an NHE1-specific inhibitor, on the day of confluence. Results. The NHE1 mRNA expression level did not change as a function of differentiation. However, the NHE2 mRNA expression levels increased on the 7th, 14th and 28th days after confluence. The NHE3 mRNA expression levels increased on the 14th and 28th days after confluence. Western blot analysis confirmed the expression of NHE1 (91 kDa), NHE2 (90 kDa) and NHE3 (93 kDa). In addition, HOE694 inhibited basolateral NHE activity by 68% at 1 μM and by 85% at 5 μM in the NHNE cells.

Original languageEnglish
Pages (from-to)286-292
Number of pages7
JournalActa Oto-Laryngologica
Issue number3
Publication statusPublished - 2005 Apr 20


All Science Journal Classification (ASJC) codes

  • Otorhinolaryngology

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