Calpain-mediated collapsin response mediator protein-1,-2, and-4 proteolysis after neurotoxic and traumatic brain injury
Calpain-mediated collapsin response mediator protein-1,-2, and-4 proteolysis after neurotoxic and traumatic brain injury
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DOI：
10.1089/neu.2006.0078
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发表时间：
2007-03-01
影响因子：
4.2
通讯作者：
Wang, Kevin K. W.
中科院分区：
文献类型：
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作者：
Zhang, Zhiqun;Ottens, Andrew K.;Wang, Kevin K. W.
溃缩蛋白反应介导蛋白（CRMPs）是神经突起生长和轴突导向的重要分子。在CRMP家族中，CRMP-2与几种神经系统疾病（阿尔茨海默病、癫痫和缺血）有关。在此，我们研究了体外神经毒素治疗和体内创伤性脑损伤（TBI）后CRMP（CRMP-1，-2，-4，-5）的完整性。用美托毒素（MTX）和NMDA处理原代皮质神经元后，观察到完整的CRMP-1、-2和-4蛋白急剧减少，同时出现不同的55-kDa和58-kDa分解产物（BDP）CRMP-2和-4分别。抑制钙蛋白酶激活阻止NMDA诱导的CRMP-2蛋白水解和CRMP-2从神经突到细胞体的重新分布，同时减轻神经突损伤和神经元细胞损伤。类似地，在TBI的体内模型受控皮质撞击（CCI）后，也发现CRMP-1、CRMP-2和CRMP-4在大鼠皮质和海马中降解。观察到55 kDa CRMP-2 BDP的出现以时间依赖性方式增加，在同侧皮质中为24 - 48 h，在海马中为48 h。TBI后观察到的55-kDa CRMP-2 BDP通过将幼稚脑裂解物与活化的钙蛋白酶-2但不与活化的半胱天冬酶-3体外孵育来再现。序列分析揭示了CRMP-2的C-末端附近的几个可能的切割位点。总的来说，这项研究表明，CRMP-1，-2，和-4降解后，急性创伤性和神经毒性损伤。此外，钙蛋白酶-2被确定为CRMP-2的可能的蛋白水解介质兴奋毒性损伤和TBI后，这似乎与神经元细胞损伤和神经突损伤相关。钙蛋白酶介导的CRMPs截短可能是TBI后神经突起再生的抑制因素。
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.