A novel role for Oct-2 in the lipopolysaccharide-mediated induction of resistin gene expression in RAW264.7 cells
Journal
Biochemical Journal
Journal Volume
402
Journal Issue
2
Pages
387-395
Date Issued
2007
Author(s)
Abstract
Although resistin was first suggested as a possible link between obesity and diabetes, we have demonstrated previously that expression of resistin is induced by LPS (lipopolysaccharide). In the present study, we showed that LPS increased levels of resistin mRNA and promoter activity in murine RAW264.7 macrophages. Investigation of cis-regulatory elements in the mouse resistin promoter required for LPS-mediated induction showed that an Octamer (ATTTGCAT) element, located at -914 to -907, was required for maximal promoter activity in response to LPS stimulation. Co-transfection of RAW264.7 cells with a resistin promoter-luciferase construct and an Oct-1 or Oct-2 expression plasmid (pCG-Oct-1 or pCG-Oct-2) showed that Oct-2, but not Oct-1, activated the resistin promoter upon LPS treatment. Binding of Oct-2 to the Octamer element was demonstrated by supershift DNA-affinity precipitation and chromatin immunoprecipitation assays. Reverse transcription-PCR and Western blot results showed that levels of Oct-2 mRNA and protein were both up-regulated by LPS in RAW264.7 cells. The LPS-induced increase in Oct-2 protein was inhibited by LY294002 (a phosphoinositide 3-kinase inhibitor) post-transcriptionally, and the inhibition also resulted in a lower response of both resistin mRNA and promoter activity to LPS treatment. Moreover, specific knockdown of Oct-2 by RNA interference impaired the LPS-induced increase in resistin mRNA and promoter activity. Together, these results indicate that Oct-2 is involved in the LPS-mediated induction of resistin gene expression in macrophages and suggest that activation of Oct-2 is a part of LPS signalling pathways in macrophages. ? 2007 Biochemical Society.
SDGs
Other Subjects
Bioassay; Gene expression; Lipids; Macrophages; Proteins; RNA; Immunoprecipitation assays; Mouse resistin promoter; Obesity; Oct-2; Western blot; Polysaccharides; 2 morpholino 8 phenylchromone; inducible nitric oxide synthase; lipopolysaccharide; messenger RNA; octamer transcription factor 1; octamer transcription factor 2; resistin; 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; chromone derivative; inducible nitric oxide synthase; lipopolysaccharide; messenger RNA; morpholine derivative; octamer transcription factor 2; resistin; Retn protein, mouse; transactivator protein; unclassified drug; animal cell; article; binding affinity; cell line; chromatin immunoprecipitation; controlled study; DNA flanking region; gene activity; gene expression; genetic transfection; in vitro study; macrophage; mouse; mutagenesis; nonhuman; plasmid; priority journal; promoter region; protein binding; protein function; reverse transcription polymerase chain reaction; RNA interference; Western blotting; animal; DNA responsive element; drug effect; gene expression; genetics; metabolism; molecular genetics; nucleotide sequence; Murinae; 5' Flanking Region; Animals; Base Sequence; Cell Line; Chromones; Gene Expression; Lipopolysaccharides; Macrophages; Mice; Molecular Sequence Data; Morpholines; Mutagenesis; Nitric Oxide Synthase Type II; Octamer Transcription Factor-2; Promoter Regions (Genetics); Protein Binding; Resistin; Response Elements; RNA Interference; RNA, Messenger; Trans-Activators; Transfection
Type
journal article