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，但由于其被认为是不受控制的性质，因此几乎没有努力开发针对病理性坏死的特定疗法。这一概念最近受到了肿瘤坏死因子受体家族成员下游的内在死亡途径可以启动坏死性死亡的发现的挑战，这表明坏死可以被特异性地靶向抑制。我们最近开发了坏死抑制素，这是一种有效且选择性的“坏死性凋亡”小分子抑制剂，坏死性凋亡是一种由TNF α和Fas受体引发的程序性坏死形式。使用Necrostatin-1直接建立坏死性凋亡作为体内缺血性脑损伤后神经元细胞死亡的主要组成部分。创伤性脑损伤是年轻人和儿童死亡和终身残疾的主要原因，然而创伤性脑细胞死亡和相关神经功能障碍的机制尚未得到很好的表征。我们已经表明，TNF和Fas在小鼠受控皮质撞击（CCI）后的组织病理学和功能结果中起着关键作用。由于TNF和Fas是公认的坏死性凋亡诱导剂，我们研究了坏死性凋亡是否有助于TBI后的结果。我们发现，necrostatin-1减少了CCI后小鼠的组织损伤，并显着改善了功能结果。这些结果表明，necrostatin-1的靶点，受体相互作用蛋白激酶1（RIPK 1），可能是TBI治疗的一个令人兴奋的新靶点。为了进一步研究RIPK 1在TBI中的作用，我们提出了三个具体的目的：1）在与TBI相关的各种体外神经元死亡范例中，使用敲低来建立RIPK 1在神经元细胞死亡中的作用（RIPK 1 shRNA）和显性阴性（RIPK 1 K45 M）策略; 2）使用AAV-8病毒载体在体内用shRNA RIPK 1或RIPK 1 K45 M构建体转导神经元，证明RIPK 1对体内脑创伤的关键贡献;和3）确定在体内培养的神经元和TBI后受损脑中坏死性凋亡期间起作用的RIPK 1相关信号传导途径。公共卫生相关性：拟议项目的工作可以为创伤性脑损伤患者提供新的治疗方法。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.