title: Toll-like receptors 2 and 4 mediate hyperglycemia induced macrovascular aortic endothelial cell inflammation and perturbation of the endothelial glycocalyx.
abstract: OBJECTIVE
  Hyperglycemia-induced inflammation is central to the vascular complications in diabetes. Toll-like receptors (TLRs) are key players in regulating inflammatory responses. There are sparse data on the role of TLR2 and TLR4 in regulating human macrovascular aortic endothelial cells (HMAECs) inflammation and glycocalyx dysfunction under hyperglycemia. We examined the role of TLR2/4 in the above dysfunctions in HMAEC under high glucose (HG) conditions.
  
  
  METHODS
  HMAECs were treated with high or normal glucose and TLR-2, TLR-4, MyD88, IRF3, TRIF, nuclear NF-κB p65, IL-8, IL-1β, TNF-α, MCP-1, ICAM-1, sVCAM-1, monocyte adhesion to HMAECs, heparan sulfate and hyaluronic acid were measured.
  
  
  RESULTS
  HG upregulated TLR2 and TLR4 mRNA and protein and increased both MyD88 and non-MyD88 pathways, NF-κB p65, inflammatory biomediators, and monocyte adhesion to HMAECs. Heparan sulfate protein expression was reduced and hyaluronic acid secretion was increased on HG exposure. Inhibition of TLR2 and TLR4 signaling by inhibitory peptides and knockdown of TLR-2 and TLR-4 gene expression by siRNA attenuated HG induced inflammation, leukocyte adhesion and glycocalyx dysfunction. An increase in ROS paralleled the increase in TLR-2/4 and antioxidants treatment reduced TLR-2/4 expression and downstream inflammatory biomediators.
  
  
  CONCLUSIONS
  Thus hyperglycemia induces HMAEC inflammation and glycocalyx dysfunction through TLR-2/4 pathway activation via increased ROS.
authors.affiliation: Laboratory of Atherosclerosis and Metabolic Research, Department of Pathology and Internal, Medicine, University of California Davis Medical Center, Sacramento, CA, United States.
authors.forename: Roma
authors.initials: R
authors.lastname: Pahwa
authors.affiliation: Laboratory of Atherosclerosis and Metabolic Research, Department of Pathology and Internal, Medicine, University of California Davis Medical Center, Sacramento, CA, United States.
authors.forename: Palanisamy
authors.initials: P
authors.lastname: Nallasamy
authors.affiliation: Laboratory of Atherosclerosis and Metabolic Research, Department of Pathology and Internal, Medicine, University of California Davis Medical Center, Sacramento, CA, United States; Veterans Affairs Medical Center, Mather, CA, United States. Electronic address: ijialal@ucdavis.edu.
authors.forename: Ishwarlal
authors.initials: I
authors.lastname: Jialal
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001025:Aortitis / Q000150:complications / Q000209:etiology* / Q000517:prevention & control; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000188:drug therapy; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy; D003925:Diabetic Angiopathies / Q000209:etiology / Q000517:prevention & control; D004730:Endothelium, Vascular / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D019276:Glycocalyx / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D006943:Hyperglycemia / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008856:Microscopy, Fluorescence; D018384:Oxidative Stress / Q000187:drug effects; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4
keywords: Glycocalyx; Hyperglycemia; Inflammation; Macrovascular complications; Toll-like receptors