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The role of 12/15‐Lipoxygenase in a Mouse Model of Alcoholic Liver Disease
Author(s) -
Kirpich Irina,
Miller Matthew,
Ramsden Christopher,
Feldstein Ariel,
McClain Craig
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.628.8
Subject(s) - alcoholic liver disease , liquid diet , proinflammatory cytokine , arachidonic acid , steatohepatitis , chemistry , endocrinology , medicine , polyunsaturated fatty acid , linoleic acid , oil red o , fatty liver , biochemistry , inflammation , biology , ethanol , fatty acid , enzyme , cirrhosis , disease , adipogenesis , adipose tissue
/Aim 12/15‐Lipoxygenase (12/15‐LOX) catalyzes the oxidation of free and esterified polyunsaturated fatty acids, predominantly, linoleic and arachidonic, generating the whole spectrum of bioactive lipid mediators. This enzyme is involved in the regulation of various homeostatic processes as well as in the pathogenesis of multiple diseases. Recently published studies from our group and others have shown that experimental and clinical alcoholic liver disease was associated with elevated oxidized linoleic acid metabolites (OXLAMs), specifically 9‐ and 13‐hydroxy‐octadecadienoic acids (9‐ and 13‐HODEs). The aim of the present study was to examine the role of 12/15‐LOX in an animal model of ALD. Materials and Methods Eight‐week‐old male 12/15‐LOX knockout mice (12/15‐LOX −/− ), and their genetically unaltered wild type (WT) counterparts were fed Lieber–DeCarli control (isocaloric maltose‐dextrin) or ethanol (5% w/v) liquid diets ad libitum for 10 days plus a single binge ethanol administration (5 g/kg) by gavage, whereas mice in control groups were gavaged with isocaloric maltose dextrin. Liver histopathological changes were estimated by hematoxylin and eosin staining. Liver triglyceride accumulation was assessed by biochemical assay and Oil Red O staining. Liver injury was evaluated by plasma ALT and AST activity. Liver inflammation was determined by hepatic proinflammatory gene expression. Chloroacetate esterase staining was used to evaluate necroinflammatory changes. TUNEL staining was used to determine hepatic apoptotic cell death. Plasma OXLAMs were analyzed on LC‐MS and GCxGC/TOF‐MS platforms. Results Chronic‐binge alcohol administration resulted in a marked increase in plasma OXLAM levels, specifically 9‐HODE and 13‐HODE, in parallel with up‐regulation of hepatic 12/15‐LOX in WT animals. These effects were associated with hepatic steatosis, inflammation and injury. 12/15‐LOX genetic depletion did not reduced hepatic steatosis caused by EtOH, but did ameliorate hepatic injury as assessed by ALT (231.2+32.8 U/L in WT vs 148.4+48.6 U/L in 12/15‐LOX −/− ) and AST (279.1+36.7 U/L in WT vs 177.1+28.3 U/L in 12/15‐LO −/− ) levels. 12/15‐LOX deficiency did not affect hepatic apoptosis; while neutrophil infiltration was significantly reduced in 12/15‐LOX deficient mice compared to WT animals. 12/15‐LOX deficiency prevented EtOH‐induced pro‐inflammatory cytokine and chemokine expression, including Tnf‐α and Mcp1 mRNA levels. Conclusion 12/15 LOX plays an important role in the pathogenesis of experimental ALD, in part, via increased production of OXLAMs. 12/15‐LOX and OXLAMs may represent novel therapeutic targets in ALD management Support or Funding Information Study supported by the NIH and Veterans Administration.