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- Title
Effects of lipids on ENaC activity in cultured mouse cortical collecting duct cells.
- Authors
Su Wang; Fei Meng; Jingyuan Xu; Yuchun Gu; Wang, Su; Meng, Fei; Xu, Jingyuan; Gu, Yuchun
- Abstract
Direct effects on epithelial Na+ channels (ENaC) activity by lipids, e.g., arachidonic acid (AA), eicosatetraynoic acid (ETYA), linoleic acid (LA), stearic acid (SA), hydroxyeicosatetraenoic acid (HETE), 11,12-epoxyeicosatrienoic acid (EET), (PGF2), and (PGE2), in cultured mouse cortical collecting duct (M1) cells were clarified by using single-channel recordings in this study. In a cell-attached recording, a bath application of 10 microM AA significantly reduced the ENaC open probability (NPo), whereas 10 microM ETYA or 5 microM LA only induced a slight inhibition. The inside-out recording as a standard protocol was thereafter performed to examine effects of these lipids on ENaC activity. Within 10 min after the formation of the inside-out configuration, the NPo of ENaC in cultured mouse cortical collecting duct (M1) cells remained relatively constant. Application of ETYA or LA or SA exhibited a similar inhibition on the channel NPo when applied to the extracellular side, suggesting that fatty acids could exert a nonspecific inhibition on ENaC activity. 11,12-EET, a metabolite of AA via the cytochrome P450 epoxygenase pathway, significantly inhibited the ENaC NPo, whereas 20-HETE, a metabolite of AA via the hydroxylase pathway, only caused a small inhibition of the ENaC NPo, to a similar degree as that seen with ETYA and LA. However, both PGE2 and PGF2alpha significantly enhanced the ENaC NPo. These results suggest that fatty acids exert a nonspecific effect on ENaC activity due to the interaction between the channel proximity and the lipid. The opposite effects of 11,12-EET and prostaglandin (PG) implicate different mechanisms in regulation of ENaC activity by activation of epoxygenase and cyclooxygenase.
- Subjects
EPITHELIAL cells; LIPIDS; FATTY acids; METABOLITES; CYTOCHROMES; CYCLOOXYGENASES; ANIMAL experimentation; CELL culture; CELLULAR signal transduction; COMPARATIVE studies; CYTOLOGICAL techniques; KIDNEY tubules; KIDNEYS; RESEARCH methodology; MEDICAL cooperation; MICE; PROSTAGLANDINS; RESEARCH; RESEARCH funding; EVALUATION research; MEMBRANE transport proteins
- Publication
Journal of Membrane Biology, 2009, Vol 227, Issue 2, p77
- ISSN
0022-2631
- Publication type
journal article
- DOI
10.1007/s00232-008-9145-1