title: Blocking spinal CCR2 with AZ889 reversed hyperalgesia in a model of neuropathic pain.
abstract: BACKGROUND
  The CCR2/CCL2 system has been identified as a regulator in the pathogenesis of neuropathy-induced pain. However, CCR2 target validation in analgesia and the mechanism underlying antinociception produced by CCR2 antagonists remains poorly understood. In this study, in vitro and in vivo pharmacological approaches using a novel CCR2 antagonist, AZ889, strengthened the hypothesis of a CCR2 contribution to neuropathic pain and provided confidence over the possibilities to treat neuropathic pain with CCR2 antagonists.
  
  
  RESULTS
  We provided evidence that dorsal root ganglia (DRG) cells harvested from CCI animals responded to stimulation by CCL2 with a concentration-dependent calcium rise involving PLC-dependent internal stores. This response was associated with an increase in evoked neuronal action potentials suggesting these cells were sensitive to CCR2 signalling. Importantly, treatment with AZ889 abolished CCL2-evoked excitation confirming that this activity is CCR2-mediated. Neuronal and non-neuronal cells in the spinal cord were also excited by CCL2 applications indicating an important role of spinal CCR2 in neuropathic pain. We next showed that in vivo spinal intrathecal injection of AZ889 produced dose-dependent analgesia in CCI rats. Additionally, application of AZ889 to the exposed spinal cord inhibited evoked neuronal activity and confirmed that CCR2-mediated analgesia involved predominantly the spinal cord. Furthermore, AZ889 abolished NMDA-dependent wind-up of spinal withdrawal reflex pathway in neuropathic animals giving insight into the spinal mechanism underlying the analgesic properties of AZ889.
  
  
  CONCLUSIONS
  Overall, this study strengthens the important role of CCR2 in neuropathic pain and highlights feasibility that interfering on this mechanism at the spinal level with a selective antagonist can provide new analgesia opportunities.
authors.affiliation: AstraZeneca R&D Montréal, 7171 Frédérick Banting, Ville St-Laurent (Montréal) Québec, Canada, H4S 1Z9.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Serrano
authors.forename: Michel
authors.initials: M
authors.lastname: Paré
authors.forename: Fraser
authors.initials: F
authors.lastname: McIntosh
authors.forename: Steven J R
authors.initials: SJ
authors.lastname: Elmes
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martino
authors.forename: Claudia
authors.initials: C
authors.lastname: Jomphe
authors.forename: Etienne
authors.initials: E
authors.lastname: Lessard
authors.forename: Paola M C
authors.initials: PM
authors.lastname: Lembo
authors.forename: François
authors.initials: F
authors.lastname: Vaillancourt
authors.forename: Martin N
authors.initials: MN
authors.lastname: Perkins
authors.forename: Chang Qing
authors.initials: CQ
authors.lastname: Cao
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D016503:Drug Delivery Systems; D005727:Ganglia, Spinal / Q000473:pathology; D006930:Hyperalgesia / Q000188:drug therapy*; D009437:Neuralgia / Q000188:drug therapy*; D010879:Piperazines / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054390:Receptors, CCR2 / Q000037:antagonists & inhibitors* / Q000502:physiology; D015398:Signal Transduction; D013116:Spinal Cord / Q000473:pathology*
chemical_list: C557084:AZ 889; D010879:Piperazines; D054390:Receptors, CCR2