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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2010-4-29
pubmed:abstractText
Disruption of the peroxisomal acyl-CoA oxidase 1 (Acox1) gene in the mouse results in the development of severe microvesicular hepatic steatosis and sustained activation of peroxisome proliferator-activated receptor-alpha (PPARalpha). These mice manifest spontaneous massive peroxisome proliferation in regenerating hepatocytes and eventually develop hepatocellular carcinomas. Human ACOX1, the first and rate-limiting enzyme of the peroxisomal beta-oxidation pathway, has two isoforms including ACOX1a and ACOX1b, transcribed from a single gene. As ACOX1a shows reduced activity toward palmitoyl-CoA as compared with ACOX1b, we used adenovirally driven ACOX1a and ACOX1b to investigate their efficacy in the reversal of hepatic phenotype in Acox1(-/-) mice. In this study, we show that human ACOX1b is markedly effective in reversing the ACOX1 null phenotype in the mouse. In addition, expression of human ACOX1b was found to restore the production of nervonic (24:1) acid and had a negative impact on the recruitment of coactivators to the PPARalpha-response unit, which suggests that nervonic acid might well be an endogenous PPARalpha antagonist, with nervonoyl-CoA probably being the active form of nervonic acid. In contrast, restoration of docosahexaenoic (22:6) acid level, a retinoid-X-receptor (RXRalpha) agonist, was dependent on the concomitant hepatic expression of both ACOX1a and ACOX1b isoforms. This is accompanied by a specific recruitment of RXRalpha and coactivators to the PPARalpha-response unit. The human ACOX1b isoform is more effective than the ACOX1a isoform in reversing the Acox1 null phenotype in the mouse. Substrate utilization differences between the two ACOX1 isoforms may explain the reason why ACOX1b is more effective in metabolizing PPARalpha ligands.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1530-0307
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
90
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
696-708
pubmed:dateRevised
2010-12-28
pubmed:meshHeading
pubmed-meshheading:20195242-Alternative Splicing, pubmed-meshheading:20195242-Amino Acid Sequence, pubmed-meshheading:20195242-Animals, pubmed-meshheading:20195242-Cell Proliferation, pubmed-meshheading:20195242-Docosahexaenoic Acids, pubmed-meshheading:20195242-Fatty Acids, Monounsaturated, pubmed-meshheading:20195242-Gene Expression Profiling, pubmed-meshheading:20195242-Gene Expression Regulation, Enzymologic, pubmed-meshheading:20195242-Humans, pubmed-meshheading:20195242-Immunoblotting, pubmed-meshheading:20195242-Isoenzymes, pubmed-meshheading:20195242-Liver, pubmed-meshheading:20195242-Mice, pubmed-meshheading:20195242-Mice, Knockout, pubmed-meshheading:20195242-Mice, Transgenic, pubmed-meshheading:20195242-Molecular Sequence Data, pubmed-meshheading:20195242-Oxidoreductases, pubmed-meshheading:20195242-PPAR alpha, pubmed-meshheading:20195242-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:20195242-Sequence Homology, Amino Acid
pubmed:year
2010
pubmed:articleTitle
Reversal of mouse Acyl-CoA oxidase 1 (ACOX1) null phenotype by human ACOX1b isoform [corrected].
pubmed:affiliation
INSERM, UMR 866, Dijon, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural