Effects of Ghrelin on human alveolar epithelial cell apoptosis in response to lipopolysaccharide through AKT/ERK signaling pathway
10.3969/j.issn.1000-484X.2017.08.002
- VernacularTitle:Ghrelin通过AKT/ERK信号通路对LPS诱导的肺泡上皮细胞凋亡的影响
- Author:
Chunrong HUANG
;
Wanmei HE
;
Hui YI
;
Haichong ZHENG
;
Mian ZENG
- Keywords:
Apoptosis;
AKT signaling;
ERK signaling;
Ghrelin;
LPS;
NO
- From:
Chinese Journal of Immunology
2017;33(8):1129-1134
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the protective effects of Ghrelin on LPS-induced apoptosis of human alveolar epithelial A549 cells,along with the possible molecular mechanisms.Methods: CCK-8 assay was used to examine the cell viability of A549 treated by LPS.Apoptosis of A549 cells was measured by TUNEL.NO(Nitric oxide)production was detected by NO-specific fluorescent probe 3-Amino,4-aminomethyl-2′,7′-difluoresceindiacetate(DAF-FM DA).Western blot was also performed to examine the expressions of iNOS(inducible nitric oxide synthase),AKT,ERK,p-AKT,p-ERK and apoptotic proteins,such as Bcl-2,Bax,and cleaved caspase-3.Results: LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration-and time-dependent manners accompanied with increased Bax and cleaved caspase-3 production,coupled with decreased Bcl-2 levels.Meanwhile,LPS promoted iNOS expression and the production of NO.Ghrelin pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression.TUNEL analysis showed that Ghrelin could decrease the apoptosis induced by LPS in A549(P<0.05).Simultaneously,LPS remarkably decreased the expression of p-AKT and p-ERK in A549 cells,which was abrogated by Ghrelin pretreatment.However,Ghrelin had no significant effect on NO production induced by LPS.Conclusion: Ghrelin reduces LPS-induced apoptosis of human alveolar epithelial cells partly through activating the AKT and ERK pathway,but the level of iNOS derived NO could not be reduced.
