title: Brown Adipose Tissue Regulates Small Artery Function Through NADPH Oxidase 4-Derived Hydrogen Peroxide and Redox-Sensitive Protein Kinase G-1α.
abstract: Biomedical interest in brown adipose tissue (BAT) has increased since the discovery of functionally active BAT in adult humans. Although white adipose tissue (WAT) influences vascular function, vascular effects of BAT are elusive. Thus, we investigated the regulatory role and putative vasoprotective effects of BAT, focusing on hydrogen peroxide, nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4), and redox-sensitive signaling.
  
  
  
  Vascular reactivity was assessed in wild-type and Nox4-knockout mice (Nox4-/-) by wire myography in the absence and presence of perivascular adipose tissue of different phenotypes from various adipose depots: (1) mixed WAT/BAT (inguinal adipose tissue) and (2) WAT (epididymal visceral fat) and BAT (intrascapular fat). In wild-type mice, epididymal visceral fat and perivascular adipose tissue increased EC50to noradrenaline without affecting maximum contraction. BAT increased EC50and significantly decreased maximum contraction, which were prevented by a hydrogen peroxide scavenger (polyethylene glycated catalase) and a specific cyclic GMP-dependent protein kinase G type-1α inhibitor (DT-3), but not by inhibition of endothelial nitric oxide synthase or guanylate cyclase. BAT induced dimerization of cyclic GMP-dependent protein kinase G type-1α and reduced phosphorylation of myosin light chain phosphatase subunit 1 and myosin light chain 20. BAT from Nox4-knockout mice displayed reduced hydrogen peroxide levels and no anticontractile effects. Perivascular adipose tissue from β3agonist-treated mice displayed browned perivascular adipose tissue and an increased anticontractile effect.
  
  
  
  We identify a novel vasoprotective action of BAT through an anticontractile effect that is mechanistically different to WAT. Specifically, BAT, via Nox4-derived hydrogen peroxide, induces cyclic GMP-dependent protein kinase G type-1α activation, resulting in reduced vascular contractility. BAT may constitute an interesting therapeutic target to restore vascular function and prevent vascular complications in cardiovascular diseases.
authors.affiliation: From the Institute of Cardiovascular Medicine and Sciences, University of Glasgow, United Kingdom.
authors.forename: Malou
authors.initials: M
authors.lastname: Friederich-Persson
authors.affiliation: From the Institute of Cardiovascular Medicine and Sciences, University of Glasgow, United Kingdom.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Nguyen Dinh Cat
authors.affiliation: From the Institute of Cardiovascular Medicine and Sciences, University of Glasgow, United Kingdom.
authors.forename: Patrik
authors.initials: P
authors.lastname: Persson
authors.affiliation: From the Institute of Cardiovascular Medicine and Sciences, University of Glasgow, United Kingdom.
authors.forename: Augusto C
authors.initials: AC
authors.lastname: Montezano
authors.affiliation: From the Institute of Cardiovascular Medicine and Sciences, University of Glasgow, United Kingdom. Rhian.Touyz@glasgow.ac.uk.
authors.forename: Rhian M
authors.initials: RM
authors.lastname: Touyz
mesh_terms: D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000201:enzymology*; D052436:Adipose Tissue, White / Q000201:enzymology; D000818:Animals; D062965:Cyclic GMP-Dependent Protein Kinase Type I / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005260:Female; D005838:Genotype; D006861:Hydrogen Peroxide / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000201:enzymology*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D019899:Paracrine Communication; D010641:Phenotype; D015398:Signal Transduction; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D006861:Hydrogen Peroxide; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; D062965:Cyclic GMP-Dependent Protein Kinase Type I; C569720:Prkg1 protein, mouse
keywords: brown adipose tissue; cardiovascular disease; catalase; contractility; myosin light chain; perivascular adipose tissue; vascular function