Expression of the Na+/H+ and Cl-/HCO-3 exchanger isoforms in proximal and distal human airways
Department of Medicine, University of Illinois at Chicago and Westside Veterans Affairs Medical Center, Chicago, Illinois 60612 Recent studies have indicated the presence of Na + /H + and Cl /HCO 3 exchange activities in lung alveolar and tracheal tissues of various species. To date, the identity of...
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Published in | American journal of physiology. Lung cellular and molecular physiology Vol. 276; no. 6; pp. 971 - L978 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.06.1999
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Subjects | |
Online Access | Get full text |
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Summary: | Department of Medicine, University of Illinois at Chicago and
Westside Veterans Affairs Medical Center, Chicago, Illinois 60612
Recent studies have indicated the presence of
Na + /H +
and
Cl /HCO 3
exchange activities in lung alveolar and tracheal tissues of various
species. To date, the identity of the
Na + /H +
(NHE) and
Cl /HCO 3
(AE) exchanger isoforms and their regional distribution in human
airways are not known. Molecular species of the NHE and AE gene
families and their relative abundance in the human airway regions were
assessed utilizing RT-PCR and the RNase protection assay, respectively.
Organ donor lung epithelia from various bronchial regions (small,
medium, and large bronchi and trachea) were harvested for RNA
extraction. Gene-specific primers for the human NHE and AE isoforms
were utilized for RT-PCR. Our results demonstrated that NHE1, AE2, and
brain AE3 isoforms were expressed in all regions of the human airways,
whereas NHE2, NHE3, AE1, and cardiac AE3 were not detected. RNase
protection studies for NHE1 and AE2, utilizing
glyceraldehyde-3-phosphate dehydrogenase as an internal standard,
demonstrated that there were regional differences in the NHE1 mRNA
levels in human airways. In contrast, the levels of AE2 mRNA remained
unchanged. Differential expression of these isoforms in the human
airways may have functional significance related to the airway
absorption and secretion of electrolytes.
human lung; anion exchangers; cation exchangers; reverse
transcription-polymerase chain reaction; ribonuclease protection |
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ISSN: | 1040-0605 0002-9513 1522-1504 2163-5773 |
DOI: | 10.1152/ajplung.1999.276.6.L971 |