RIPK1: A new target for traumatic brain injury?

描述（由申请人提供）：坏死是人类疾病的主要原因，但由于其不可控制的性质，针对病理性坏死的特异性治疗方法很少。这一观点最近受到了挑战，发现肿瘤坏死因子受体家族成员的内在死亡途径下游可以启动坏死性死亡，这表明坏死可以被特异性地抑制。我们最近开发了坏死性他汀类药物，这是一种有效的选择性小分子抑制剂，用于“坏死性下垂”，这是一种由TNF α和Fas受体引发的程序性坏死。在体内用坏死他汀-1直接证实坏死下垂是缺血性脑损伤后神经元细胞死亡的主要组成部分。外伤性脑损伤是青壮年和儿童死亡和终身残疾的主要原因，然而，外伤性脑细胞死亡和相关神经功能障碍的机制尚不清楚。我们已经证明TNF和Fas在小鼠控制性皮质冲击（CCI）后的组织病理学和功能结果中起关键作用。由于TNF和Fas是公认的坏死性上睑下垂的诱导剂，我们研究了坏死性上睑下垂是否与TBI后的预后有关。我们发现坏死性他汀-1减少了小鼠CCI后的组织损伤并显著改善了功能结局。这些结果表明，坏死他汀-1的靶点受体相互作用蛋白激酶1 （RIPK1）可能是TBI治疗的一个令人兴奋的新靶点。为了进一步研究RIPK1在TBI中的作用，我们提出了三个具体目标：1)通过敲低（RIPK1 shRNA）和显性阴性（RIPK1 K45M）策略，在各种与TBI相关的体外神经元死亡范式中，建立RIPK1在神经元细胞死亡中的作用；2)通过构建shRNA RIPK1或RIPK1 K45M，利用AAV-8病毒载体转导体内神经元，证明RIPK1在体内脑损伤中的关键作用；3)确定体外培养神经元和脑外伤后坏死坏死过程中ripk1相关信号通路的作用。公共卫生相关性：拟议项目中的工作可能为创伤性脑损伤患者提供一种新的治疗方法。拟议的药物治疗可能会减少脑细胞死亡，并改善幸存者的学习和记忆，从而提高他们的生活质量。

DESCRIPTION (provided by applicant): Necrosis is a major contributor to human disease, however little effort has been made to develop specific therapies targeting pathologic necrosis due it its perceived uncontrolled nature. This notion has recently been challenged by the discovery that intrinsic death pathways down stream of tumor necrosis factor receptor family members can initiate necrotic death, suggesting that necrosis can be specifically targeted for inhibition. We have recently developed necrostatins, potent and selective small molecule inhibitors of "necroptosis", a form of programmed necrosis initiated by TNF alpha and Fas receptor. Necrostatin-1 was used to directly establish necroptosis as a major component of neuronal cell death after ischemic brain injury in vivo. Traumatic brain injury is a leading cause of death and life-long disability in young adults and children, however mechanisms of traumatic brain cell death and associated neurological dysfunction are not well characterized. We have shown that TNF and Fas play a key role in histopathological and functional outcome after controlled cortical impact (CCI) in mice. Since TNF and Fas are well established inducers of necroptosis, we investigated whether necroptosis contributes to outcome after TBI. We found that necrostatin-1 reduced tissue damage and markedly improved functional outcome following CCI in mice. These results suggest that the target of necrostatin-1, receptor interacting protein kinase 1 (RIPK1), may represent an exciting new target for TBI therapy. To further investigate the role of RIPK1 in TBI, we propose three Specific Aims: 1) Establish the role of RIPK1 in neuronal cell death in a variety of in vitro neuronal death paradigms related to TBI using knockdown (RIPK1 shRNA) and dominant negative (RIPK1 K45M) strategies; 2) Demonstrate a key contribution of RIPK1 to brain trauma in vivo, using AAV-8 viral vector transduction of neurons in vivo with shRNA RIPK1 or RIPK1 K45M constructs; and 3) Determine RIPK1-related signaling pathways operative during necroptosis in cultured neurons and in injured brain after TBI in vivo. PUBLIC HEALTH RELEVANCE: Work in the proposed project could render a new treatment for patients with traumatic brain injury. The proposed drug therapy might reduce brain cell death as well as improve learning and memory in survivors, and thereby improve their quality of life.