title: Stimulation of non-neuronal muscarinic receptors enhances chemerin/ChemR23 system in dysfunctional endothelial cells.
abstract: OBJECTIVE
  Endothelial cells play a pivotal role in vascular intimal inflammation during cardiovascular diseases. The chemerin/ChemR23 system in endothelial cells is one of physiological mechanisms that regulate inflammatory responses. Our previous studies indicated that stimulation of non-neuronal muscarinic receptor (NNMR) improved endothelial dysfunction. However, the relationship between the chemerin/ChemR23 signaling axis and NNMR in endothelial cell is poorly understood. Here, we first investigated whether the modulation of chemerin/ChemR23 signaling axis is involved in NNMR-mediated endothelial protection.
  
  
  METHODS
  Cultured rat aortic endothelial cells (RAECs) were used. The ChemR23 protein expression and chemerin secretion were measured using Western blot analysis. The gene expression level of ChemR23 was examined with reverse transcriptase PCR (RT-PCR). The production of nitric oxide (NO) was determined by a nitrate reductase assay kit.
  
  
  RESULTS
  A sharp decline of chemerin secretion and ChemR23 protein/gene expression was observed in RAECs after exposed to homocysteine at concentration of 0.5 mmol/L. Arecoline (10 μmol/L) pretreatment increased ChemR23 protein expression as well as mRNA expression, and enhanced the secretion of chemerin. Arecoline could also reverse the decreased ChemR23 mRNA expression induced by uric acid, high glucose, or oxidized low-density lipoprotein. Furthermore, the modulation of arecoline on chemerin/ChemR23 signaling axis was absolutely abolished in the presence of the nonselective muscarinic receptors antagonist atropine 1 μmol/L. Additionally, arecoline improved endothelial dysfunction by increasing the reduced NO production induced by uric acid, which was blocked by anti-ChemR23 antibody.
  
  
  CONCLUSIONS
  The chemerin/ChemR23 signaling axis participates in NNMR-mediated protection against endothelial dysfunction in cardiovascular system.
authors.affiliation: Cardiovascular Drug Research Center, Institute of Health and Environmental Medicine, Academy of Military Medical Sciences, Beijing 100850, China.
authors.forename: Rui-Jun
authors.initials: RJ
authors.lastname: Zhao
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Pan
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Long
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Cui
authors.forename: Yan-Fang
authors.initials: YF
authors.lastname: Zhang
authors.forename: Hai
authors.initials: H
authors.lastname: Wang
mesh_terms: D054392:Adipokines / Q000378:metabolism; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000378:metabolism; D001115:Arecoline / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D015153:Blotting, Western; D018925:Chemokines; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D005786:Gene Expression Regulation; D006710:Homocysteine / Q000494:pharmacology; D007249:Inflammation / Q000503:physiopathology*; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019707:Receptors, Chemokine / Q000235:genetics / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D054392:Adipokines; D018925:Chemokines; C109811:Cmklr1 protein, rat; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; C560738:Rarres2 protein, rat; D019707:Receptors, Chemokine; D011976:Receptors, Muscarinic; D006710:Homocysteine; D009569:Nitric Oxide; D001115:Arecoline; D001285:Atropine