The role of TLR4-dependent sterile inflammation in mediating adverse outcomes after SAH

摘要/摘要： 蛛网膜下腔出血影响着40,000名正处于壮年的美国人；其中一半人会 12个月后死亡，三分之一的幸存者将有较差的认知结果。唯一的 我们可以在神经ICU为这些患者提供的治疗方法是用夹子夹住动脉瘤 或线圈，并给他们一种名为尼莫地平的32年历史的药物。这两种治疗方法都不是 解决持续存在的红血球引起的脑部炎症反应。我们的 初步的和已发表的数据分别确定了TLR4和小胶质细胞的作用。 在这项建议中，我们将研究细胞特异性TLR4在先天 免疫系统。具体地说，我们在TLR4上创造了2个新的条件敲除 小胶质细胞和髓样细胞。我们将测量发烧，神经细胞凋亡，血肿清除， 以及这些新的条件性基因敲除小鼠的认知结果来确定 组织内滞留的巨噬细胞和中性粒细胞对这些结果的影响。 此外，我们还将检查体内缺乏TLR4对炎症和 用免疫印迹和药物抑制剂研究TLR4依赖的细胞凋亡途径 发炎。据我们所知，TLR4在血肿消退中的作用尚未得到证实 更不用说以细胞特异性的方式进行检查了，脑部炎症和细胞凋亡也没有 这些新的条件性基因敲除中的信号转导通路。 根据我们的发现，打破TLR4依赖的平衡的新策略 炎症和细胞凋亡抑制可能被利用。另外，我们的初步数据 提示TLR4可能在清除血肿中起作用；细胞特异性策略可能是 用于减轻血肿负担和消除红细胞诱发的脑损伤 炎症反应。

Abstract/Summary: Subarachnoid hemorrhage affects 40,000 Americans in the prime of their lives; half of them will die in 12 months, and one third of the survivors will have a poor cognitive outcome. The only treatments we can offer these patients in the Neuro-ICU are securing the aneurysm with a clip or coils and giving them a 32-year-old drug called nimodipine. Neither of these treatments addresses the red blood cell-induced cerebral inflammatory response which persists. Our preliminary, as well as published, data establish a role for TLR4 and microglia individually. In this proposal we will be investigating the function of cell specific TLR4 within the innate immune system. Specifically, we have created 2 novel conditional knockouts of TLR4 on microglia and myeloid cells. We will measure fever, neuronal apoptosis, hematoma clearance, and cognitive outcome in these novel conditional knockout mice to determine the extent to which the tissue resident macrophage versus neutrophil affects these outcomes. Furthermore, we will also be examining the in vivo effects of lack of TLR4 on inflammatory and apoptotic pathways using western blot and pharmacological inhibitors of TLR4-dependent inflammation. To our knowledge, the role of TLR4 in hematoma resolution has not been examined, let alone in a cell-specific manner, nor have cerebral inflammatory and apoptotic signal transduction pathways in these novel conditional knockouts. Based on our findings, novel strategies to tip the balance between TLR4-dependent inflammation and apoptotic inhibition may be exploited. Additionally, our preliminary data indicates that TLR4 might have a role in hematoma clearance; a cell-specific strategy might be employed to decrease hematoma burden and abrogate the RBC-induced cerebral inflammatory response.