title: Uncoupling protein-2 mediates DPP-4 inhibitor-induced restoration of endothelial function in hypertension through reducing oxidative stress.
abstract: OBJECTIVE
  Although uncoupling protein 2 (UCP2) negatively regulates intracellular reactive oxygen species (ROS) production and protects vascular function, its participation in vascular benefits of drugs used to treat cardiometabolic diseases is largely unknown. This study investigated whether UCP2 and associated oxidative stress reduction contribute to the improvement of endothelial function by a dipeptidyl peptidase-4 inhibitor, sitagliptin, in hypertension.
  
  
  RESULTS
  Pharmacological inhibition of cyclooxygenase-2 (COX-2) but not COX-1 prevented endothelial dysfunction, and ROS scavengers reduced COX-2 mRNA and protein expression in spontaneously hypertensive rats (SHR) renal arteries. Angiotensin II (Ang II) evoked endothelium-dependent contractions (EDCs) in C57BL/6 and UCP2 knockout (UCP2KO) mouse aortae. Chronic sitagliptin administration attenuated EDCs in SHR arteries and Ang II-infused C57BL/6 mouse aortae and eliminated ROS overproduction in SHR arteries, which were reversed by glucagon-like peptide 1 receptor (GLP-1R) antagonist exendin 9-39, AMP-activated protein kinase (AMPK)α inhibitor compound C, and UCP2 inhibitor genipin. By contrast, sitagliptin unaffected EDCs in Ang II-infused UCP2KO mice. Sitagliptin increased AMPKα phosphorylation, upregulated UCP2, and downregulated COX-2 expression in arteries from SHR and Ang II-infused C57BL/6 mice. Importantly, exendin 9-39, compound C, and genipin reversed the inhibitory effect of GLP-1R agonist exendin-4 on Ang II-stimulated mitochondrial ROS rises in SHR endothelial cells. Moreover, exendin-4 improved the endothelial function of renal arteries from SHR and hypertensive patients.
  
  
  METHODS
  We elucidate for the first time that UCP2 serves as an important signal molecule in endothelial protection conferred by GLP-1-related agents. UCP2 could be a useful target in treating hypertension-related vascular events.
  
  
  CONCLUSIONS
  UCP2 inhibits oxidative stress and downregulates COX-2 expression through GLP-1/GLP-1R/AMPKα cascade.
authors: 1 Department of Physiology and Pathophysiology, Peking University Health Science Center , Peking, China .
authors: Limei
authors: L
authors: Liu
authors: Jian
authors: J
authors: Liu
authors: Xiao Yu
authors: XY
authors: Tian
authors: Wing Tak
authors: WT
authors: Wong
authors: Chi Wai
authors: CW
authors: Lau
authors: Aimin
authors: A
authors: Xu
authors: Gang
authors: G
authors: Xu
authors: Chi Fai
authors: CF
authors: Ng
authors: Xiaoqiang
authors: X
authors: Yao
authors: Yuansheng
authors: Y
authors: Gao
authors: Yu
authors: Y
authors: Huang
mesh_terms: D000818:Animals; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000494:pharmacology*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism*; D000077270:Exenatide; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D008954:Models, Biological; D018384:Oxidative Stress / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology; D011719:Pyrazines / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D017382:Reactive Oxygen Species / Q000378:metabolism; D012077:Renal Artery / Q000187:drug effects / Q000378:metabolism; D000068900:Sitagliptin Phosphate; D014230:Triazoles / Q000494:pharmacology; D000071246:Uncoupling Protein 2; D014661:Vasoconstriction / Q000187:drug effects; D014688:Venoms / Q000494:pharmacology
chemical_list: D054873:Dipeptidyl-Peptidase IV Inhibitors; D007473:Ion Channels; D024101:Mitochondrial Proteins; D010455:Peptides; D011719:Pyrazines; D017382:Reactive Oxygen Species; D014230:Triazoles; C000604389:UCP2 protein, human; C000604390:Ucp2 protein, mouse; C000604391:Ucp2 protein, rat; D000071246:Uncoupling Protein 2; D014688:Venoms; D000077270:Exenatide; D051546:Cyclooxygenase 2; D018819:Dipeptidyl Peptidase 4; D000068900:Sitagliptin Phosphate