上皮钠通道
阿米洛利
蛋白激酶C
化学
蛋白激酶A
钙磷酸蛋白C
细胞生物学
顶膜
激酶
分子生物学
内科学
内分泌学
生物
钠
生物化学
医学
膜
有机化学
作者
Jae Young Choi,Yo Han Choi,Su Jin Kim,Eun Ju Son,Hyun Seung Choi,Joo‐Heon Yoon
标识
DOI:10.1016/j.ejphar.2007.04.026
摘要
Recent reports have shown that cytokines inhibit fluid absorption by suppressing Na+ channel activity in various epithelia. In this study, we investigated the role of epithelial sodium channel (ENaC) in fluid absorption in normal human middle ear epithelial (NHMEE) cells, as well as the effects of Interleukin (IL)-1β on ENaC expression and fluid absorption in NHMEE cells. We confirmed that ENaC α, β and γ were predominantly expressed on the apical surface of the NHMEE cells by immunocytochemistry. Addition of amiloride, a potent ENaC blocker, to apical membranes of NHMEE cells decreased the fluid absorption rate in a dose-dependent manner. Treatment with 10 ng/ml IL-1β for 24 h suppressed ENaC β expression, the ENaC-dependent short-circuit current (Isc), and ENaC-dependent fluid absorption. When the NHMEE cells were pretreated with a phospholipase C (PLC)inhibitor (U73122, 10 μM), a protein kinase C (PKC) inhibitor (Calphostin C, 0.1 μM), or extracellular signal regulated kinase (ERK) 1/2 inhibitor (PD98059, 10 μM), the amiloride-sensitive currents in IL-1β-treated cells were reversed to control levels; an effect not seen with SB202190 (an inhibitor of p38 mitogen-activated protein (MAP) kinase) or SP600125 (a reversible inhibitor of c-Jun N-terminal kinase). In this study we showed that ENaC is essential for fluid absorption in NHMEE cells and that IL-1β suppresses the ENaC-dependent current via the PLC-PKC-ERK1/2 pathway. These results suggest that IL-1β may contribute to fluid retention in otitis media with effusion by changing electrolyte transport and reducing middle ear epithelial fluid absorption.
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