title: Cannabinoid CB(2)  receptors modulate ERK-1/2 kinase signalling and NO release in microglial cells stimulated with bacterial lipopolysaccharide.
abstract: OBJECTIVE
  Cannabinoid (CB) receptor agonists have potential utility as anti-inflammatory drugs in chronic immune inflammatory diseases. In the present study, we characterized the signal transduction pathways affected by CB(2) receptors in quiescent and lipopolysaccharide (LPS)-stimulated murine microglia.
  
  
  METHODS
  We examined the effects of the synthetic CB(2) receptor ligand, JWH-015, on phosphorylation of MAPKs and NO production.
  
  
  RESULTS
  Stimulation of CB(2) receptors by JWH-015 activated JNK-1/2 and ERK-1/2 in quiescent murine microglial cells. Furthermore, CB(2) receptor activation increased p-ERK-1/2 at 15 min in LPS-stimulated microglia. Surprisingly, this was reduced after 30 min in the presence of both LPS and JWH-015. The NOS inhibitor L-NAME blocked the ability of JWH-015 to down-regulate the LPS-induced p-ERK increase, indicating that activation of CB(2) receptors reduced effects of LPS on ERK-1/2 phosphorylation through NO. JWH-015 increased LPS-induced NO release at 30 min, while at 4 h CB(2) receptor stimulation had an inhibitory effect. All the effects of JWH-015 were significantly blocked by the CB(2) receptor antagonist AM 630 and, as the inhibition of CB(2) receptor expression by siRNA abolished the effects of JWH-015, were shown to be mediated specifically by activation of CB(2) receptors.
  
  
  CONCLUSIONS
  Our results demonstrate that CB(2) receptor stimulation activated the MAPK pathway, but the presence of a second stimulus blocked MAPK signal transduction, inhibiting pro-inflammatory LPS-induced production of NO. Therefore, CB(2) receptor agonists may promote anti-inflammatory therapeutic responses in activated microglia.
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Merighi
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Gessi
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Katia
authors.initials: K
authors.lastname: Varani
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Carolina
authors.initials: C
authors.lastname: Simioni
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Fazzi
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Prisco
authors.initials: P
authors.lastname: Mirandola
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Section and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Via Fossato di Mortara, Ferrara, ItalyDepartment of Human Anatomy, Pharmacology and Forensic Medicine, Institute of Normal Human Anatomy, Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Borea
mesh_terms: D000818:Animals; D002460:Cell Line; D020868:Gene Silencing; D007211:Indoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D007211:Indoles; D008070:Lipopolysaccharides; D009573:Nitrites; D034741:RNA, Small Interfering; D043885:Receptor, Cannabinoid, CB2; D051197:Toll-Like Receptor 4; D009569:Nitric Oxide; C094023:iodopravadoline; C402944:JHW 015