title: Anti-inflammatory effects of angiotensin-(1-7) in ischemic stroke.
abstract: Previously we demonstrated that central administration of angiotensin-(1-7) [Ang-(1-7)] into rats elicits significant cerebroprotection against ischemic stroke elicited by endothelin-1 induced middle cerebral artery occlusion. Ang-(1-7), acting via its receptor Mas, reduced cerebral infarct size, and rats exhibited improved performance on neurological exams. These beneficial actions of Ang-(1-7) were not due to inhibition of the effects of endothelin-1 on cerebral vasoconstriction or effects on cerebral blood flow, and so we considered other potential mechanisms. Here we investigated the possibility that the Ang-(1-7)-induced cerebroprotection involves an anti-inflammatory effect, since stroke-induced cerebral damage includes an excessive intracerebral inflammatory response. Our quantitative RT-PCR analyses revealed that central Ang-(1-7) treatment attenuates the increased expression of mRNAs for inducible nitric oxide synthase (iNOS), several pro-inflammatory cytokines and cluster of differentiation molecule 11b (microglial marker) within the cerebral cortex following endothelin-1 induced stroke. Western blotting confirmed similar changes in iNOS protein expression in the cerebral cortex. In support of these observations, immunostaining revealed the presence of immunoreactive Mas on activated microglia within the cerebral cortical infarct zone, and in vitro experiments demonstrated that lipopolysaccharide-induced increases in nitric oxide production in glial cultures are attenuated by Ang-(1-7) acting via Mas. Collectively these findings demonstrate an anti-inflammatory action of Ang-(1-7) in the brain, and suggest that the cerebroprotective action of this peptide in ischemic stroke may involve effects on nitric oxide generation by microglia.
authors.affiliation: Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Regenhardt
authors.forename: Fiona
authors.initials: F
authors.lastname: Desland
authors.forename: Adam P
authors.initials: AP
authors.lastname: Mecca
authors.forename: David J
authors.initials: DJ
authors.lastname: Pioquinto
authors.forename: Aqeela
authors.initials: A
authors.lastname: Afzal
authors.forename: J
authors.initials: J
authors.lastname: Mocco
authors.forename: Colin
authors.initials: C
authors.lastname: Sumners
mesh_terms: D000803:Angiotensin I / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology / Q000627:therapeutic use*; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D017628:Microglia / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology / Q000627:therapeutic use*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D013047:Specific Pathogen-Free Organisms; D020521:Stroke / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D009569:Nitric Oxide; D000803:Angiotensin I; D052247:Nitric Oxide Synthase Type II; C118790:angiotensin I (1-7)