title: Uric acid, a nucleic acid degradation product, down-regulates dsRNA-triggered arthritis.
abstract: Uric acid, the naturally occurring degradation product of purine metabolism, is a danger signal, driving maturation of dendritic cells. It is well known that uric acid crystals display potent proinflammatory properties--the cause of gout--whereas the biological properties of soluble uric acid are less well documented. We have demonstrated previously that nucleic acids of endogenous and exogenous origin display proinflammatory properties. The aim of the present study was to assess the impact of soluble uric acid on in vivo inflammatory responses. Mice were administered with uric acid suspension in saline or saline alone prior to induction of neutrophil-mediated inflammation, delayed-type hypersensitivity, histamin-induced edema (measure of vasodilation capacity), as well as double-stranded (ds)RNA-triggered arthritis. Frequency and severity of arthritis were decreased significantly in mice exposed to dsRNA and simultaneously treated with uric acid as compared with saline-treated controls. Also, granulocyte-mediated inflammatory response and vasodilation capacity were reduced significantly in mice treated with uric acid as compared with their control group. The data suggest that down-regulation of inflammation was mediated by skewing the inflammatory response from the peripheral sites to the peritoneal cavity and down-regulating vasodilatatory capacity and thereby affecting leukocyte migration. In contrast, the T cell-mediated delayed-type hypersensitivity reaction was not affected significantly in mice exposed to uric acid. These findings demonstrate that uric acid displays a potent, distant anti-inflammatory effect in vivo. This property seems to be mediated by down-regulation of neutrophil influx to the site of inflammatory insult.
authors.affiliation: Department of Rheumatology and Inflammation Research, University of Göteborg, Sweden. fariba.zare@rheuma.gu.se
authors.forename: Fariba
authors.initials: F
authors.lastname: Zare
authors.forename: Mattias
authors.initials: M
authors.lastname: Magnusson
authors.forename: Tomas
authors.initials: T
authors.lastname: Bergström
authors.forename: Mikael
authors.initials: M
authors.lastname: Brisslert
authors.forename: Elisabet
authors.initials: E
authors.lastname: Josefsson
authors.forename: Anna
authors.initials: A
authors.lastname: Karlsson
authors.forename: Andrej
authors.initials: A
authors.lastname: Tarkowski
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000276:immunology*; D002633:Chemotaxis / Q000187:drug effects / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects / Q000276:immunology*; D004487:Edema / Q000139:chemically induced / Q000276:immunology / Q000503:physiopathology; D005260:Female; D006968:Hypersensitivity, Delayed / Q000139:chemically induced / Q000276:immunology / Q000503:physiopathology; D007166:Immunosuppressive Agents / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D018836:Inflammation Mediators / Q000009:adverse effects / Q000276:immunology; D007596:Joints / Q000187:drug effects / Q000276:immunology / Q000503:physiopathology; D051379:Mice; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology; D009696:Nucleic Acids / Q000276:immunology* / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000009:adverse effects / Q000276:immunology*; D014527:Uric Acid / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000276:immunology
chemical_list: D007166:Immunosuppressive Agents; D018836:Inflammation Mediators; D009696:Nucleic Acids; D012330:RNA, Double-Stranded; D014527:Uric Acid