title: Inhibition of TLR4 attenuates vascular dysfunction and oxidative stress in diabetic rats.
abstract: Hyperglycemia-induced reactive oxygen species (ROS) production plays a major role in the pathogenesis of diabetic vascular dysfunction. However, the underlying mechanisms remain unclear. Toll-like receptor 4 (TLR4), a key component of innate immunity, is known to be activated during diabetes. Therefore, we hypothesize that hyperglycemia activates TLR4 signaling in vascular smooth muscle cells (VSMCs) that triggers ROS production and causes vascular dysfunction. Rat mesenteric VSMCs exposed to high glucose (25 mmol/l) increased TLR4 expression and activated TLR4 signaling via upregulation of myeloid differentiation factor 88 (MyD88). TLR4 inhibitor CLI-095 significantly attenuated elevated levels of ROS and nuclear factor-kappa B (NF-κB) activity in VSMCs exposed to high glucose. Mesenteric arteries from streptozotocin-induced diabetic rats treated with CLI-095 (2 mg/kg/day) intraperitoneally for 2 weeks exhibited reduced ROS generation and attenuated noradrenaline-induced contraction. These results suggest that hyperglycemia-induced ROS generation and NF-κB activation in VSMCs are at least, in part, mediated by TLR4 signaling. Therefore, strategies to block TLR4 signaling pathways pose a promising avenue to alleviate diabetic-induced vascular complications.
  
  
  CONCLUSIONS
  High glucose-induced TLR4 activation in vascular smooth muscle cells. Inhibition of TLR4 attenuated high glucose-induced ROS production and NF-κB activity in VSMC. Suppression of TLR4 signaling attenuated mesenteric contraction in diabetic rat.
authors.affiliation: Department of Physiology, Georgia Regents University, Augusta, GA, USA. mcarrill@nyit.edu.|Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Northern Blvd., Old Westbury, NY, 11568, USA. mcarrill@nyit.edu.
authors.forename: Maria Alicia
authors.initials: MA
authors.lastname: Carrillo-Sepulveda
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Spitler
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Deepesh
authors.initials: D
authors.lastname: Pandey
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Dan E
authors.initials: DE
authors.lastname: Berkowitz
authors.affiliation: Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, 142-8501, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D001786:Blood Glucose; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D013449:Sulfonamides; D051197:Toll-Like Receptor 4; C507035:ethyl 6-(N-(2-chloro-4-fluorophenyl)sulfamoyl)cyclohex-1-ene-1-carboxylate; D005947:Glucose
keywords: Diabetes; High glucose; NF-κB; ROS; TLR4; Vascular smooth muscle cell