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Cytochrome P450 2E1 potentiates ethanol induction of hypoxia and HIF-1α in vivo.
Free Radic Biol Med. 2013 Oct; 63:175-86.FR

Abstract

Ethanol induces hypoxia and elevates HIF-1α in the liver. CYP2E1 plays a role in the mechanisms by which ethanol generates oxidative stress, fatty liver, and liver injury. This study evaluated whether CYP2E1 contributes to ethanol-induced hypoxia and activation of HIF-1α in vivo and whether HIF-1α protects against or promotes CYP2E1-dependent toxicity in vitro. Wild-type (WT), CYP2E1-knock-in (KI), and CYP2E1 knockout (KO) mice were fed ethanol chronically; pair-fed controls received isocaloric dextrose. Ethanol produced liver injury in the KI mice to a much greater extent than in the WT and KO mice. Protein levels of HIF-1α and downstream targets of HIF-1α activation were elevated in the ethanol-fed KI mice compared to the WT and KO mice. Levels of HIF prolyl hydroxylase 2, which promotes HIF-1α degradation, were decreased in the ethanol-fed KI mice in association with the increases in HIF-1α. Hypoxia occurred in the ethanol-fed CYP2E1 KI mice as shown by an increased area of staining using the hypoxia-specific marker pimonidazole. Hypoxia was lower in the ethanol-fed WT mice and lowest in the ethanol-fed KO mice and all the dextrose-fed mice. In situ double staining showed that pimonidazole and CYP2E1 were colocalized to the same area of injury in the hepatic centrilobule. Increased protein levels of HIF-1α were also found after acute ethanol treatment of KI mice. Treatment of HepG2 E47 cells, which express CYP2E1, with ethanol plus arachidonic acid (AA) or ethanol plus buthionine sulfoximine (BSO), which depletes glutathione, caused loss of cell viability to a greater extent than in HepG2 C34 cells, which do not express CYP2E1. These treatments elevated protein levels of HIF-1α to a greater extent in E47 cells than in C34 cells. 2-Methoxyestradiol, an inhibitor of HIF-1α, blunted the toxic effects of ethanol plus AA and ethanol plus BSO in the E47 cells in association with inhibition of HIF-1α. The HIF-1α inhibitor also blocked the elevated oxidative stress produced by ethanol/AA or ethanol/BSO in the E47 cells. These results suggest that CYP2E1 plays a role in ethanol-induced hypoxia, oxidative stress, and activation of HIF-1α and that HIF-1α contributes to CYP2E1-dependent ethanol-induced toxicity. Blocking HIF-1α activation and actions may have therapeutic implications for protection against ethanol/CYP2E1-induced oxidative stress, steatosis, and liver injury.

Authors+Show Affiliations

Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23669278

Citation

Wang, Xiaodong, et al. "Cytochrome P450 2E1 Potentiates Ethanol Induction of Hypoxia and HIF-1α in Vivo." Free Radical Biology & Medicine, vol. 63, 2013, pp. 175-86.
Wang X, Wu D, Yang L, et al. Cytochrome P450 2E1 potentiates ethanol induction of hypoxia and HIF-1α in vivo. Free Radic Biol Med. 2013;63:175-86.
Wang, X., Wu, D., Yang, L., Gan, L., & Cederbaum, A. I. (2013). Cytochrome P450 2E1 potentiates ethanol induction of hypoxia and HIF-1α in vivo. Free Radical Biology & Medicine, 63, 175-86. https://doi.org/10.1016/j.freeradbiomed.2013.05.009
Wang X, et al. Cytochrome P450 2E1 Potentiates Ethanol Induction of Hypoxia and HIF-1α in Vivo. Free Radic Biol Med. 2013;63:175-86. PubMed PMID: 23669278.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cytochrome P450 2E1 potentiates ethanol induction of hypoxia and HIF-1α in vivo. AU - Wang,Xiaodong, AU - Wu,Defeng, AU - Yang,Lili, AU - Gan,Lixia, AU - Cederbaum,Arthur I, Y1 - 2013/05/10/ PY - 2013/02/14/received PY - 2013/04/03/revised PY - 2013/05/03/accepted PY - 2013/5/15/entrez PY - 2013/5/15/pubmed PY - 2013/11/2/medline KW - 2-ME KW - 2-methoxyestradiol KW - 3-NT KW - 3-nitrotyrosine KW - 4-HNE KW - 4-hydroxynonenal KW - AA KW - ALT KW - BSO KW - CYP2E1 KW - Ethanol KW - Free radicals KW - GSH KW - HE KW - HIF KW - HIF prolyl hydroxylase 2 KW - HIF-1α KW - HPH-2 KW - Hepatotoxicity KW - IHC KW - KI KW - KO KW - LDHA KW - MDA KW - Oxidative stress KW - PNP KW - ROS KW - TBARS KW - WT KW - alanine aminotransferase KW - arachidonic acid KW - cytochrome P450 2E1 KW - hematoxylin–eosin KW - hypoxia-inducible factor KW - immunohistochemistry KW - knock-in KW - knockout KW - l-buthionine sulfoximine KW - lactate dehydrogenase A KW - malondialdehyde KW - p-nitrophenol KW - reactive oxygen species KW - reduced glutathione KW - thiobarbituric acid-reactive substances KW - wild type SP - 175 EP - 86 JF - Free radical biology & medicine JO - Free Radic Biol Med VL - 63 N2 - Ethanol induces hypoxia and elevates HIF-1α in the liver. CYP2E1 plays a role in the mechanisms by which ethanol generates oxidative stress, fatty liver, and liver injury. This study evaluated whether CYP2E1 contributes to ethanol-induced hypoxia and activation of HIF-1α in vivo and whether HIF-1α protects against or promotes CYP2E1-dependent toxicity in vitro. Wild-type (WT), CYP2E1-knock-in (KI), and CYP2E1 knockout (KO) mice were fed ethanol chronically; pair-fed controls received isocaloric dextrose. Ethanol produced liver injury in the KI mice to a much greater extent than in the WT and KO mice. Protein levels of HIF-1α and downstream targets of HIF-1α activation were elevated in the ethanol-fed KI mice compared to the WT and KO mice. Levels of HIF prolyl hydroxylase 2, which promotes HIF-1α degradation, were decreased in the ethanol-fed KI mice in association with the increases in HIF-1α. Hypoxia occurred in the ethanol-fed CYP2E1 KI mice as shown by an increased area of staining using the hypoxia-specific marker pimonidazole. Hypoxia was lower in the ethanol-fed WT mice and lowest in the ethanol-fed KO mice and all the dextrose-fed mice. In situ double staining showed that pimonidazole and CYP2E1 were colocalized to the same area of injury in the hepatic centrilobule. Increased protein levels of HIF-1α were also found after acute ethanol treatment of KI mice. Treatment of HepG2 E47 cells, which express CYP2E1, with ethanol plus arachidonic acid (AA) or ethanol plus buthionine sulfoximine (BSO), which depletes glutathione, caused loss of cell viability to a greater extent than in HepG2 C34 cells, which do not express CYP2E1. These treatments elevated protein levels of HIF-1α to a greater extent in E47 cells than in C34 cells. 2-Methoxyestradiol, an inhibitor of HIF-1α, blunted the toxic effects of ethanol plus AA and ethanol plus BSO in the E47 cells in association with inhibition of HIF-1α. The HIF-1α inhibitor also blocked the elevated oxidative stress produced by ethanol/AA or ethanol/BSO in the E47 cells. These results suggest that CYP2E1 plays a role in ethanol-induced hypoxia, oxidative stress, and activation of HIF-1α and that HIF-1α contributes to CYP2E1-dependent ethanol-induced toxicity. Blocking HIF-1α activation and actions may have therapeutic implications for protection against ethanol/CYP2E1-induced oxidative stress, steatosis, and liver injury. SN - 1873-4596 UR - https://www.unboundmedicine.com/medline/citation/23669278/Cytochrome_P450_2E1_potentiates_ethanol_induction_of_hypoxia_and_HIF_1α_in_vivo_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0891-5849(13)00215-3 DB - PRIME DP - Unbound Medicine ER -