Calpain-mediated collapsin response mediator protein-1, -2, and -4 proteolysis after neurotoxic and traumatic brain injury

J Neurotrauma. 2007 Mar;24(3):460-72. doi: 10.1089/neu.2006.0078.

Abstract

Collapsin response mediator proteins (CRMPs) are important molecules in neurite outgrowth and axonal guidance. Within the CRMP family, CRMP-2 has been implicated in several neurological diseases (Alzheimer's, epilepsy, and ischemia). Here, we investigated the integrity of CRMPs (CRMP-1, -2, -4, -5) after in vitro neurotoxin treatment and in vivo traumatic brain injury (TBI). After maitotoxin (MTX) and NMDA treatment of primary cortical neurons, a dramatic decrease of intact CRMP-1, -2 and -4 proteins were observed, accompanied by the appearance of distinct 55-kDa and 58-kDa breakdown products (BDP) for CRMP-2 and -4, respectively. Inhibition of calpain activation prevented NMDA-induced CRMP-2 proteolysis and redistribution of CRMP-2 from the neurites to the cell body, while attenuating neurite damage and neuronal cell injury. Similarly, CRMP-1, -2, and -4 were also found degraded in rat cortex and hippocampus following controlled cortical impact (CCI), an in vivo model of TBI. The appearance of the 55-kDa CRMP-2 BDP was observed to increase, in a time-dependent manner, between 24 and 48 h in the ipsilateral cortex, and by 48 hours in the hippocampus. The observed 55-kDa CRMP-2 BDP following TBI was reproduced by in vitro incubation of naive brain lysate with activated calpain-2, but not activated caspase-3. Sequence analysis revealed several possible cleavage sites near the C-terminus of CRMP-2. Collectively, this study demonstrated that CRMP-1, -2, and -4 are degraded following both acute traumatic and neurotoxic injury. Furthermore, calpain-2 was identified as the possible proteolytic mediator of CRMP-2 following excitotoxic injury and TBI, which appears to correlate well with neuronal cell injury and neurite damage. It is possible that the calpain-mediated truncation of CRMPs following TBI may be an inhibiting factor for post-injury neurite regeneration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Brain / pathology
  • Brain Injuries / metabolism*
  • Calpain / metabolism
  • Calpain / physiology*
  • Caspase 3 / metabolism
  • Cell Death
  • Cells, Cultured
  • Cerebral Cortex / metabolism
  • Cerebral Cortex / pathology
  • Electrophoresis, Polyacrylamide Gel
  • Excitatory Amino Acid Agonists / toxicity
  • Hippocampus / metabolism
  • Hippocampus / pathology
  • Immunoblotting
  • Immunohistochemistry
  • L-Lactate Dehydrogenase / metabolism
  • Marine Toxins / toxicity
  • N-Methylaspartate / toxicity
  • Nerve Tissue Proteins / metabolism*
  • Neurons / metabolism
  • Neurons / pathology
  • Neurotoxicity Syndromes / metabolism*
  • Oxocins / toxicity
  • Phosphoproteins / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Adaptor Proteins, Signal Transducing
  • Dpysl3 protein, rat
  • Dpysl5 protein, rat
  • Excitatory Amino Acid Agonists
  • Marine Toxins
  • Nerve Tissue Proteins
  • Oxocins
  • Phosphoproteins
  • collapsin response mediator protein-1
  • collapsin response mediator protein-2
  • N-Methylaspartate
  • maitotoxin
  • L-Lactate Dehydrogenase
  • Calpain
  • Caspase 3