Calpain-mediated collapsin response mediator protein-1, -2, and -4 proteolysis after neurotoxic and traumatic brain injury.
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.
Zhang
Zhiqun
Z
Department of Psychiatry, Center for Neuroproteomics and Biomarkers Research, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610, USA.
Ottens
Andrew K
AK
Sadasivan
Shankar
S
Kobeissy
Firas H
FH
Fang
Tie
T
Hayes
Ronald L
RL
Wang
Kevin K W
KK
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000473:pathology; D001930:Brain Injuries / Q000378:metabolism*; D002154:Calpain / Q000378:metabolism / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D015151:Immunoblotting; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008387:Marine Toxins / Q000633:toxicity; D016202:N-Methylaspartate / Q000633:toxicity; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D020258:Neurotoxicity Syndromes / Q000378:metabolism*; D035964:Oxocins / Q000633:toxicity; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000098855:Collapsin Response Mediator Protein 1; D000095702:Polyether Toxins
D048868:Adaptor Proteins, Signal Transducing; D002154:Calpain; D053148:Caspase 3; D018690:Excitatory Amino Acid Agonists; D036341:Intercellular Signaling Peptides and Proteins; D007770:L-Lactate Dehydrogenase; D008387:Marine Toxins; D016202:N-Methylaspartate; D009419:Nerve Tissue Proteins; D035964:Oxocins; D010750:Phosphoproteins; D000098855:Collapsin Response Mediator Protein 1; C449760:Dpysl3 protein, rat; C413755:Dpysl5 protein, rat; C095114:collapsin response mediator protein-2; C020394:maitotoxin; D000095702:Polyether Toxins