title: Disruption of NMDAR-CRMP-2 signaling protects against focal cerebral ischemic damage in the rat middle cerebral artery occlusion model.
abstract: Collapsin response mediator protein 2 (CRMP-2), traditionally viewed as an axon/dendrite specification and axonal growth protein, has emerged as nidus in regulation of both pre- and post-synaptic Ca ( 2+) channels. Building on our discovery of the interaction and regulation of Ca ( 2+) channels by CRMP-2, we recently identified a short sequence in CRMP-2 which, when appended to the transduction domain of HIV TAT protein, suppressed acute, inflammatory and neuropathic pain in vivo by functionally uncoupling CRMP-2 from the Ca ( 2+) channel. Remarkably, we also found that this region attenuated Ca ( 2+) influx via N-methylD-Aspartate receptors (NMDARs) and reduced neuronal death in a moderate controlled cortical impact model of traumatic brain injury (TBI). Here, we sought to extend these findings by examining additional neuroprotective effects of this peptide (TAT-CBD3) and exploring the biochemical mechanisms by which TAT-CBD3 targets NMDARs. We observed that an intraperitoneal injection of TAT-CBD3 peptide significantly reduced infarct volume in an animal model of focal cerebral ischemia. Neuroprotection was observed when TAT-CBD3 peptide was given either prior to or after occlusion but just prior to reperfusion. Surprisingly, a direct biochemical complex was not resolvable between the NMDAR subunit NR2B and CRMP-2. Intracellular application of TAT-CBD3 failed to inhibit NMDAR current. NR2B interactions with the post synaptic density protein 95 (PSD-95) remained intact and were not disrupted by TAT-CBD3. Peptide tiling of intracellular regions of NR2B revealed two 15-mer sequences, in the carboxyl-terminus of NR2B, that may confer binding between NR2B and CRMP-2 which supports CRMP-2's role in excitotoxicity and neuroprotection.
authors.affiliation: Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Brittain
authors.forename: Rui
authors.initials: R
authors.lastname: Pan
authors.forename: Haitao
authors.initials: H
authors.lastname: You
authors.forename: Tatiana
authors.initials: T
authors.lastname: Brustovetsky
authors.forename: Nickolay
authors.initials: N
authors.lastname: Brustovetsky
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Zamponi
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Lee
authors.forename: Rajesh
authors.initials: R
authors.lastname: Khanna
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000188:drug therapy* / Q000503:physiopathology; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy* / Q000503:physiopathology; D036341:Intercellular Signaling Peptides and Proteins; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D010455:Peptides / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D016194:Receptors, N-Methyl-D-Aspartate; C095114:collapsin response mediator protein-2; D054322:tat Gene Products, Human Immunodeficiency Virus; D002118:Calcium