Non-canonical NF-kappaB signaling and Sur1-Trpm4 in traumatic brain injury

背景：创伤性脑损伤是神经精神病学发展的主要危险因素。 受伤后很长时间内出现的对生活质量有负面影响的问题。先前在脑外伤动物模型中的工作已经完成 反复表明，不良神经行为后遗症，包括认知功能障碍，焦虑，和 抑郁样症状与慢性先天免疫反应有关，涉及小胶质细胞和 星形胶质细胞。尽管它在许多涉及大多数器官的炎症情况下都有重要的文献记载 令人惊讶的是，包括大脑在内，非规范的核因子-kappaB信号(p52：RelB)还没有被确定 TBI前情提要。我们实验室的新工作证明了非正则核因子-kappaB的新发现 肿瘤坏死因子样弱凋亡诱导因子(TWEEP)信号在脑损伤中的作用显著，尤其是在脑损伤中。 星形胶质细胞，并持续数月。新的工作还发现了一个新的非正则核因子的下游靶点- KappaB--Sur1-Trpm4通道。Sur1-Trpm4以前与血脑屏障功能障碍有关，但 不是脑损伤后星形胶质细胞功能或脑损伤后神经行为障碍。我们的初步数据显示，调整- 诱导的非典型核因子-kappaB信号在脑损伤后1个月内逐渐上调，并可能 负责星形胶质细胞中Sur1-Trpm的转录表达。此外，我们的初步数据表明 星形胶质细胞Sur1-Trpm4在调控下游基因表达中起关键作用 趋化因子/趋化离子效应因子，趋化因子(C-C基序)配体2(CCL2)，参与炎症和 颅脑损伤后的神经行为缺陷。TWEE、Sur1-Trpm4和CCL2病理性三联体的阐明 将确定非典型的核因子-kappaB在脑损伤中的作用，并将识别新的、可药物的 旨在解决脑外伤后神经行为异常的目标。对……的理解日益深入 非典型的核因子-kappaB信号有望突出选择性靶向的新治疗策略。 描述：在目标1中，使用延迟(第3天)给药的格列本脲和星形胶质细胞特异性 在雄性和雌性两种脑外伤小鼠模型中Abcc8/Sur1的缺失，我们将确认我们的试点数据 表明非典型的NF-kappaB信号、Sur1-Trpm4的表达和CCL2的表达是协同作用的。 脑损伤后星形胶质细胞中存在CCL2表达和神经行为明显相关 星形细胞生长因子1。在目标2中，我们将证实和扩展来自大脑的体内和体外初步数据 TWINE、染色质免疫沉淀和膜片钳灌流建立非典型核因子-2的作用 KappaB在功能性Sur1-Trpm4通道中的表达。在目标3中，我们将在体内和体外展开 Sur1-Trpm4在细胞内钙依赖基因转录调控中作用的初步研究 下游趋化因子/离子亲和性效应因子CCL2通过活化T细胞的核因子。这个项目，是第一个 研究非规范的NF-kappaB信号在脑损伤中的作用及其在Sur1-Trpm4表达中的作用，有望 确定新的、可用药的靶点，以解决脑外伤后的认知功能障碍、焦虑和抑郁。

BACKGROUND: Traumatic brain injury (TBI) is a major risk factor for the development of neuropsychiatric problems long after injury that negatively impact quality-of-life. Previous work in animal models of TBI has repeatedly shown that adverse neurobehavioral sequelae, including cognitive dysfunction, anxiety, and depression-like symptoms are associated with chronic innate immune responses involving microglia and astrocytes. Despite its documented importance in numerous inflammatory conditions involving most organs including the brain, surprisingly, non-canonical NF-kappaB signaling (p52:RelB) has not been identified previously in TBI. New work from our laboratory demonstrates the novel finding that non-canonical NF-kappaB signaling by tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is prominent in TBI, especially in astrocytes, and persists for months. New work also identifies a novel downstream target of non-canonical NF- kappaB -- the Sur1-Trpm4 channel. Sur1-Trpm4 previously was linked to blood-brain barrier dysfunction, but not to post-TBI astrocyte function or post-TBI neurobehavioral deficits. Our preliminary data show that TWEAK- induced non-canonical NF-kappaB signaling is upregulated progressively during 1 month post-TBI, and may be responsible for transcriptional expression of Sur1-Trpm in astrocytes. Moreover, our preliminary data suggest that astrocytic Sur1-Trpm4 plays a crucial role in regulating the expression of the downstream chemokine/ionotropic effector, chemokine (C-C motif) ligand 2 (CCL2), implicated in inflammation and neurobehavioral deficits post-TBI. Elucidating the pathological triad involving TWEAK, Sur1-Trpm4 and CCL2 in astrocytes will establish the role of non-canonical NF-kappaB in TBI, and will identifying novel, drugable targets to address post-TBI neurobehavioral abnormalities. An increasingly sophisticated understanding of non-canonical NF-kappaB signaling promises to highlight novel therapeutic strategies for selective targeting. DESCRIPTION: In Aim 1, using delayed (day-3) administration of glibenclamide along with astrocyte-specific deletion of Abcc8/Sur1 in two mouse models of TBI in males and females, we will confirm our pilot data showing that non-canonical NF-kappaB signaling, Sur1-Trpm4 expression and CCL2 expression are co- present in astrocytes in vivo post-TBI, and that CCL2 expression and neurobehavior are explicitly linked to astrocytic Sur1. In Aim 2, we will corroborate and expand upon in vivo and in vitro preliminary data from brain infusion of TWEAK, chromatin immunoprecipitation, and patch clamp to establish the role of non-canonical NF- kappaB in the expression of functional Sur1-Trpm4 channels. In Aim 3, we will expand upon in vivo and in vitro preliminary data to establish the role of Sur1-Trpm4 in regulating Ca2+-dependent gene transcription of the downstream chemokine/ionotropic effector, CCL2 via nuclear factor of activated T cells. This project, the first to examine non-canonical NF-kappaB signaling in TBI and its role in Sur1-Trpm4 expression, is expected to identify novel, drugable targets to address post-TBI cognitive dysfunction, anxiety, and depression.