title: Effects of incretin agonists on endothelial nitric oxide synthase expression and nitric oxide synthesis in human coronary artery endothelial cells exposed to TNFα and glycated albumin.
abstract: BACKGROUND
  There have been a number of beneficial effects of incretin agonists on the cardiovascular system. Glycated albumin (GA) and tumor necrosis factor (TNFα) may lead to endothelial dysfunction. Due to reports of cardioprotective effects of incretin agonist, we wanted to determine if GLP-1 and exendin-4 can reverse diminished production of nitric oxide (NO) after treatment with TNFα and GA. The objective of our experiment was to study the interaction between incretin agonists and proinflammatory substances like TNFα and GA on production of NO in HCAEC.
  
  
  METHODS
  Human vascular endothelial cells from the coronary artery (HCAEC) were used. The mRNA expression and protein level of endothelial nitric oxide synthase (eNOS) and inducible (iNOS) were quantified. NO production was measured in cells using DAF-FM/DA and flow cytometry.
  
  
  RESULTS
  TNFα (10 ng/mL) decreased eNOS: mRNA by 90% and protein level by 31%. TNFα also decreased NO by 33%. GA (500 μg/mL) neither affected eNOS expression nor the protein level, but inhibited nearly all formation of NO in endothelium. GLP-1 (100 nM) and exendin-4 (1 and 10nM) decreased the amount of NO compared to control. Incubation of HCAEC with TNFα and incretin agonists did not change or moderately reduce the amount of NO compared to TNFα alone.
  
  
  CONCLUSIONS
  TNFα and GA decrease production of NO in HCAEC, presumably by inducing reactive oxygen species or eNOS uncoupling. Incretin agonists in tested concentrations in the presence of l-arginine were not able to reverse this effect and instead led to a further reduction in NO production.
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland. Electronic address: wojtekx@mp.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Garczorz
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Francuz
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Siemianowicz
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kosowska
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kłych
authors.affiliation: Department of Biochemistry, Medical University of Silesia, School of Medicine in Katowice, Poland.
authors.forename: Mohammad Reza F
authors.initials: MR
authors.lastname: Aghdam
authors.affiliation: Department of Hematology and Bone Marrow Transplantation, Medical University of Silesia, Katowice, Poland.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Jagoda
mesh_terms: D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1 / Q000096:biosynthesis; D017127:Glycation End Products, Advanced; D006801:Humans; D054795:Incretins / Q000819:agonists*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D051058:Oncogene Protein v-akt / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012709:Serum Albumin / Q000037:antagonists & inhibitors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D014688:Venoms / Q000096:biosynthesis; D000093423:Glycated Serum Albumin
chemical_list: D017127:Glycation End Products, Advanced; D054795:Incretins; D010455:Peptides; D012333:RNA, Messenger; D012709:Serum Albumin; D014409:Tumor Necrosis Factor-alpha; D014688:Venoms; D009569:Nitric Oxide; D052216:Glucagon-Like Peptide 1; D000077270:Exenatide; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D051058:Oncogene Protein v-akt; D000093423:Glycated Serum Albumin
keywords: Coronary artery endothelium; Glycated albumin; Incretin; Nitric oxide synthase; TNFα