title: Activation of cannabinoid 2 receptors protects against cerebral ischemia by inhibiting neutrophil recruitment.
abstract: Activation of the cannabinoid 2 receptor (CB(2)) reduces ischemic injury in several organs. However, the mechanisms underlying this protective action are unclear. In a mouse model of ischemic stroke, we show that the CB(2) agonist JWH-133 (1 mg . kg(-1) . d(-1)) decreases the infarct size measured 3 d after onset of ischemia. The neuroprotective effect of JWH-133 was lost in CB(2)-deficient mice, confirming the specificity of JWH-133. Analysis of bone marrow chimeric mice revealed that bone marrow-derived cells mediate the CB(2) effect on ischemic brain injury. CB(2) activation reduced the number of neutrophils in the ischemic brain as shown by FACS analysis and by measuring the levels of the neutrophil marker enzyme myeloperoxidase. Indeed, we found in vitro that CB(2) activation inhibits adherence of neutrophils to brain endothelial cells. JWH-133 (1 microM) also interfered with the migration of neutrophils induced by the endogenous chemokine CXCL2 (30 ng/ml) through activation of the MAP kinase p38. This effect on neutrophils is likely responsible for the neuroprotection mediated by JWH-133 because JWH-133 was no longer protective when neutrophils were depleted. In conclusion, our data demonstrate that by activating p38 in neutrophils, CB(2) agonists inhibit neutrophil recruitment to the brain and protect against ischemic brain injury.-Murikinati, S., Jüttler, E., Keinert, T., Ridder, D. A., Muhammad, S., Waibler, Z., Ledent, C., Zimmer, A., Kalinke, U., Schwaninger, M. Activation of cannabinoid 2 receptors protects against cerebral ischemia by inhibiting neutrophil recruitment.
authors.affiliation: Department of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany.
authors.forename: Sasidhar
authors.initials: S
authors.lastname: Murikinati
authors.forename: Eric
authors.initials: E
authors.lastname: Jüttler
authors.forename: Timo
authors.initials: T
authors.lastname: Keinert
authors.forename: Dirk A
authors.initials: DA
authors.lastname: Ridder
authors.forename: Sajjad
authors.initials: S
authors.lastname: Muhammad
authors.forename: Zoe
authors.initials: Z
authors.lastname: Waibler
authors.forename: Catherine
authors.initials: C
authors.lastname: Ledent
authors.forename: Andreas
authors.initials: A
authors.lastname: Zimmer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kalinke
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaninger
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D016026:Bone Marrow Transplantation; D001921:Brain / Q000166:cytology; D002545:Brain Ischemia / Q000378:metabolism* / Q000517:prevention & control*; D002186:Cannabinoids / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D054426:Chemokine CXCL2 / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology; D005434:Flow Cytometry; D015151:Immunoblotting; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D002186:Cannabinoids; D054426:Chemokine CXCL2; D053583:Interleukin-1beta; D043885:Receptor, Cannabinoid, CB2; D014409:Tumor Necrosis Factor-alpha; C432747:1,1-dimethylbutyl-1-deoxy-Delta(9)-THC