title: Marked upregulation of cholesterol 25-hydroxylase expression by lipopolysaccharide.
abstract: During screening of genes upregulated by lipopolysaccharide (LPS; endotoxin) treatment of bone marrow-derived mouse macrophages, it was unexpectedly found that cholesterol 25-hydroxylase (Ch25h) was strongly upregulated. Treatment of macrophages with 10 ng/ml of LPS for 2 h resulted in a 35-fold increase in the expression of Ch25h. In contrast, LPS treatment did not increase the expression of Cyp27a1 or Cyp7b1. The increased Ch25h expression was found to be independent of Myeloid differentiation protein 88 signaling but dependent on Toll-like receptor 4 signaling. LPS treatment of macrophages caused a 6- to 7-fold increase in cellular 25-hydroxycholesterol concentration. When macrophages were treated with increasing concentrations of 25-hydroxycholesterol, a dose-dependent release of CCL5 into the culture medium was observed. Intravenous injection of LPS in eight healthy volunteers resulted in an increase in plasma 25-hydroxycholesterol concentration. The possibility is discussed that 25-hydroxycholesterol may have a role in the inflammatory response, in addition to its more established role in the regulation of cholesterol homeostasis.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Diczfalusy
authors.forename: Katarina E
authors.initials: KE
authors.lastname: Olofsson
authors.forename: Ann-Margreth
authors.initials: AM
authors.lastname: Carlsson
authors.forename: Mei
authors.initials: M
authors.lastname: Gong
authors.forename: Douglas T
authors.initials: DT
authors.lastname: Golenbock
authors.forename: Olav
authors.initials: O
authors.lastname: Rooyackers
authors.forename: Urban
authors.initials: U
authors.lastname: Fläring
authors.forename: Harry
authors.initials: H
authors.lastname: Björkbacka
mesh_terms: D000328:Adult; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D018946:Chemokine CCL5 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D006888:Hydroxycholesterols / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013250:Steroid Hydroxylases / Q000097:blood / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D055815:Young Adult
chemical_list: C503460:Ccl5 protein, mouse; D018946:Chemokine CCL5; D006888:Hydroxycholesterols; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C007997:25-hydroxycholesterol; D013250:Steroid Hydroxylases; C507384:cholesterol 25-hydroxylase