title: Deficiency of PAR4 attenuates cerebral ischemia/reperfusion injury in mice.
abstract: Stroke is the third leading cause of death in the USA. Antithrombotic therapy targeting platelet activation is one of the treatments for ischemic stroke. Here we investigate the role of one of the thrombin receptors, protease-activated receptor 4 (PAR4), in a mouse transient middle cerebral artery occlusion (MCAO) model. After a 60 min MCAO and 23 h reperfusion, leukocyte and platelet rolling and adhesion on cerebral venules, blood-brain barrier (BBB) permeability, and cerebral edema were compared in PAR4-deficient mice and wild-type mice. Cerebral infarction volume and neuronal death were also measured. PAR4-/- mice had more than an 80% reduction of infarct volume and significantly improved neurologic and motor function compared with wild-type mice after MCAO. Furthermore, deficiency of PAR4 significantly inhibits the rolling and adhesion of both platelets and leukocytes after MCAO. BBB disruption and cerebral edema were also attenuated in PAR4-/- mice compared with wild-type animals. The results of this investigation indicate that deficiency of PAR4 protects mice from cerebral ischemia/reperfusion (I/R) injury, partially through inhibition of platelet activation and attenuation of microvascular inflammation.
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Mao
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Tuma
authors.forename: Satya P
authors.initials: SP
authors.lastname: Kunapuli
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000378:metabolism; D001929:Brain Edema / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D042783:Endothelial Cells / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000473:pathology; D006801:Humans; D020244:Infarction, Middle Cerebral Artery; D036904:Leukocyte Rolling; D051379:Mice; D018345:Mice, Knockout; D009483:Neuropsychological Tests; D015539:Platelet Activation; D044462:Receptors, Proteinase-Activated / Q000235:genetics / Q000378:metabolism*; D015427:Reperfusion Injury / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology
chemical_list: D044462:Receptors, Proteinase-Activated; C481942:protease-activated receptor 4, mouse