title: Angiotensin receptor 1 blockade reduces secretion of inflammation associated cytokines from cultured human carotid atheroma and vascular cells in association with reduced extracellular signal regulated kinase expression and activation.
abstract: BACKGROUND
  A number of studies have suggested that angiotensin II (AII) receptor type 1 (ATR1) blocking drugs (ARBs) have anti-inflammatory effects however the mechanisms responsible are poorly investigated.
  
  
  OBJECTIVE
  To determine the role of extracellular signal regulated kinase (ERK)1/2 in ARB induced anti-inflammatory effects within human carotid atherosclerosis.
  
  
  METHODS
  Atheroma samples obtained from patients undergoing carotid endarterectomy were cultured with and without ATR1 (irbesartan), ERK1/2 (PD98059), AII ([Sar(1), Ile(8)]-AII) and angiotensin converting enzyme (ACE)2 (DX600) blockade. The in vitro effects of ATR1 and ERK1/2 blockade and exogenous AII on serum stimulated healthy, primary vascular cells were also investigated. Outcome was assessed by measuring cytokine, (interleukin (IL)-6, IL-8, C-C motif chemokine (CCL)2, C-X-C motif chemokine (CXCL)5, osteoprotegerin (OPG), osteopontin (OPN), CXCL16), concentrations in supernatants and phosphorylated ERK1/2 in the tissue lysates using ELISA. ERK1/2 expression in the tissue was assessed using Western blotting.
  
  
  RESULTS
  Irbesartan reduced concentrations of IL-6, IL-8, CCL2, CXCL5, OPG, OPN and CXCL16 in both atheroma and primary vascular cell culture supernatants. The reduction in cytokine levels in the atheroma supernatant was correlated to a reduction in ERK1/2 expression in the tissue. Inhibition of ERK1/2 downregulated IL-6, IL-8 and CXCL5 in both atheroma and cell culture supernatants. AII and ACE2 blockade had no impact on cytokine or active ERK1/2 levels in the atheroma culture.
  
  
  CONCLUSIONS
  Our findings suggest that ATR1 blockade downregulates atheroma tissue ERK1/2 expression leading to a reduction in cytokine production and that a non-AII agonist ATR1 signalling response may induce expression of these inflammation associated cytokines in the atheroma.
authors.affiliation: Health Practitioners And Researchers Together-Blood, Endothelium And Tissue (HART-BEAT), Australian Institute for Tropical Health and Medicine (AITHM), School of Veterinary and Biomedical Sciences, James Cook University, Townsville, Queensland 4811, Australia. Electronic address: paula.clancy@jcu.edu.au.
authors.forename: Paula
authors.initials: P
authors.lastname: Clancy
authors.affiliation: Stroke Research Programme, School of Medicine, The Queen Elizabeth Hospital (TQEH) Campus, Adelaide University, Woodville South, South Australia, Australia.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Koblar
authors.affiliation: The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, Queensland, Australia; Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, Queensland, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Golledge
mesh_terms: D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology*; D000368:Aged; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002339:Carotid Arteries / Q000473:pathology; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D006801:Humans; D007249:Inflammation; D000077405:Irbesartan; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D053244:Osteoprotegerin / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology*; D058226:Plaque, Atherosclerotic / Q000473:pathology; D012084:Renin-Angiotensin System / Q000187:drug effects* / Q000502:physiology; D013777:Tetrazoles / Q000494:pharmacology*
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D001713:Biphenyl Compounds; D018925:Chemokines; D016207:Cytokines; C556151:DX600 peptide; D053244:Osteoprotegerin; D010455:Peptides; C506030:TNFRSF11B protein, human; D013777:Tetrazoles; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000077405:Irbesartan
keywords: Angiotensin II; Angiotensin receptor blocker; Anti-Inflammatory; Atheroma; Cytokine; Extracellular signal regulated kinase