title: Inflammatory effects of resistin on human smooth muscle cells: up-regulation of fractalkine and its receptor, CX3CR1 expression by TLR4 and Gi-protein pathways.
abstract: In the atherosclerotic plaque, smooth muscle cells (SMC) acquire an inflammatory phenotype. Resistin and fractalkine (CX3CL1) are found in human atheroma and not in normal arteries. CX3CL1 and CX3CR1 are predominately associated with SMC. We have questioned whether resistin has a role in the expression of CX3CL1 and CX3CR1 in SMC thus contributing to the pro-inflammatory status of these cells. Cultured human aortic SMC were stimulated with 100 ng/ml resistin for 4, 6, 12, and 24 h, and then CX3CL1 and CX3CR1 expression was assessed by quantitative reverse transcription with the polymerase chain reaction and Western blot. We found that resistin up-regulated CX3CL1 and CX3CR1 in SMC and induced the phosphorylation of p38MAPK and STAT3. Inhibitors of p38MAPK, JAK-STAT, NF-kB, and AP-1 significantly reduced CX3CL1 and CX3CR1 expression. Knockdown of STAT1 and STAT3 with decoy oligodeoxinucleotides and the silencing of p65 and cjun with short interfering RNA decreased CX3CL1 and CX3CR1 expression. Anti-TLR4 antibody and pertussis toxin also reduced CX3CL1 and CX3CR1 protein expression. xCELLigence experiments revealed that resistin probably uses Gi-proteins for its effect on SMC. The CX3CL1 induced by resistin exhibited a chemotactic effect on monocyte transmigration. Thus, (1) resistin contributes to the pro-inflammatory state of SMC by the up-regulation of CX3CL1 and CX3CR1 expression via a mechanism involving NF-kB, AP-1, and STAT1/3 transcription factors, (2) resistin employs TLR4 and Gi-protein signaling for its effect on SMC, (3) CX3CL1 induced by resistin is functional in monocyte chemotaxis. The data reveal new mechanisms by which resistin promotes the inflammatory phenotype of SMC.
authors.affiliation: Institute of Cellular Biology and Pathology "Nicolae Simionescu", Bucharest, Romania.
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Gan
authors.forename: Elena Dragomir
authors.initials: ED
authors.lastname: Butoi
authors.forename: Adrian
authors.initials: A
authors.lastname: Manea
authors.forename: Viorel
authors.initials: V
authors.lastname: Simion
authors.forename: Daniela
authors.initials: D
authors.lastname: Stan
authors.forename: Monica-Madalina
authors.initials: MM
authors.lastname: Parvulescu
authors.forename: Manuela
authors.initials: M
authors.lastname: Calin
authors.forename: Ileana
authors.initials: I
authors.lastname: Manduteanu
authors.forename: Maya
authors.initials: M
authors.lastname: Simionescu
mesh_terms: D001665:Binding Sites; D000073883:CX3C Chemokine Receptor 1; D002460:Cell Line; D054428:Chemokine CX3CL1 / Q000235:genetics* / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D016328:NF-kappa B / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019707:Receptors, Chemokine / Q000235:genetics* / Q000378:metabolism; D052243:Resistin / Q000494:pharmacology*; D050791:STAT Transcription Factors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000073883:CX3C Chemokine Receptor 1; C515538:CX3CL1 protein, human; C095235:CX3CR1 protein, human; D054428:Chemokine CX3CL1; D017077:Culture Media, Conditioned; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D019707:Receptors, Chemokine; D052243:Resistin; D050791:STAT Transcription Factors; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D018808:Transcription Factor AP-1; D048051:p38 Mitogen-Activated Protein Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go