Ethanol-induced expression of ET-1 and ET-BR in liver sinusoidal endothelial cells and human endothelial cells involves hypoxia-inducible factor-1alpha and microrNA-199.
Chronic alcohol consumption leads to inflammation and cirrhosis of the liver. In this study, we observed that liver sinusoidal endothelial cells (LSEC) derived from ethanol-fed rats showed several fold increases in the mRNA expression of endothelin-1 (ET-1), hypoxia-inducible factor-1alpha (HIF-1alpha), and inflammatory cytochemokines compared with control rat LSEC. We also observed the same results in acute ethanol-treated LSEC from control rats and human dermal microvascular endothelial cells. Ethanol-mediated ET-1 expression involved NADPH oxidase and HIF-1alpha activation. Furthermore, ethanol increased the expression of the ET-1 cognate receptor ET-BR in Kupffer cells and THP-1 monocytic cells, which also involved HIF-1alpha activation. Promoter analysis and chromatin immunoprecipitation showed that hypoxia response element sites in the proximal promoter of ET-1 and ET-BR were required for the binding of HIF-1alpha to up-regulate their expression. We showed that microRNAs, miR-199 among several microRNAs, attenuated HIF-1alpha and ET-1 expression, while anti-miR-199 reversed the effects, suggesting that ethanol-induced miR-199 down-regulation may contribute to augmented HIF-1alpha and ET-1 expression. Our studies, for the first time to our knowledge, show that ethanol-mediated ET-1 and ET-BR expression involve HIF-1alpha, independent of hypoxia. Additionally, ethanol-induced ET-1 expression in rat LSEC is regulated by miR-199, while in human endothelial cells, ET-1 expression is regulated by miR-199 and miR-155, indicating that these microRNAs may function as novel negative regulators to control ET-1 transcription and, thus, homeostatic levels of ET-1 to maintain microcirculatory tone.
Yeligar
Samantha
S
Department of Biochemistry and Molecular Biology, The Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Tsukamoto
Hidekazu
H
Kalra
Vijay K
VK
D000818:Animals; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D019332:Endothelin-1 / Q000819:agonists / Q000096:biosynthesis* / Q000276:immunology; D000431:Ethanol / Q000633:toxicity*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000819:agonists / Q000276:immunology / Q000378:metabolism*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D019255:NADPH Oxidases / Q000276:immunology / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D044023:Receptor, Endothelin B / Q000819:agonists / Q000096:biosynthesis* / Q000276:immunology; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology
D019332:Endothelin-1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D035683:MicroRNAs; D044023:Receptor, Endothelin B; C531408:mirn199 microRNA, human; D000431:Ethanol; D019255:NADPH Oxidases