Protective monocytes in cerebral ischemic tolerance

描述(由申请人提供)：中风是一种高度流行和破坏性的疾病，治疗选择有限。到目前为止，大多数开发中风治疗方法的努力在大型临床试验中取得的成功有限。大脑具有巨大的自我保护能力，阐明大脑如何保护自己可能会为中风的治疗提供新的见解。缺血耐受(IT)是一种亚致死性应激[预适应(PC)刺激]诱导对随后的缺血性损伤的耐受状态的现象，是内源性神经保护的一个例子。全身注射Toll样受体-4配体脂多糖(LPS)可在脑内诱导其表达。不同免疫细胞群在内毒素诱导的PC发病中可能起一定作用。特别是，单核细胞是内毒素的主要靶点，可以直接或通过调节免疫系统发挥强大的保护作用。然而，单核细胞或其他免疫细胞是否参与了内毒素诱导的内毒素血症仍有待进一步研究。确定导致内毒素诱导的IT的细胞类型(S)将是重要的，因为它将为基于这些保护性免疫细胞的缺血性卒中的新疗法提供前景。这项应用将检验这样一种假设，即内毒素-PC诱导保护性单核细胞在脑内植入，从而直接或通过调节对脑缺血的免疫反应来改善缺血性脑损伤。为此，我们将确定(A)神经保护性单核细胞亚型的起源，(B)驱动它们进入大脑的分子因素，以及(C)它们提供神经保护的机制。此外，我们将确定这些细胞是否可以通过过继转移来保护动物免受实验性中风的影响，并提供一个临床相关的治疗窗口。这些目标将使用短暂性局灶性脑缺血的小鼠模型来实现，并评估组织学和神经学结果。用流式细胞仪检测脂多糖PC对免疫细胞群的影响。

DESCRIPTION (provided by applicant): Stroke is a highly prevalent and devastating disease with limited therapeutic options. Most efforts to develop treatments for stroke have thus far met with limited success in large clinical trials. The brain has an enormous capacity for self-preservation, and elucidating how the brain protects itself may provide novel insights into stroke treatment. Ischemic tolerance (IT), a phenomenon in which application of sub-lethal stress [preconditioning (PC) stimulus; PC] induces a state of tolerance to a subsequent ischemic insult, represents an example of endogenous neuroprotection. IT can be induced in brain by systemic administration of the Toll-like receptor-4 ligand lipopolysaccharide (LPS). Different populations of immune cell could potentially play a role in PC induced by LPS. In particular, monocytes, which are the main target of LPS, can exert a powerful protective effect either directly or by modulating the immune system. However, it remains to be established whether monocytes or other immune cells play a role in the IT induced by LPS. The identification of the cell type(s) responsible for LPS induced IT would be important as it would offer the prospect of novel therapies for ischemic stroke based on these protective immune cells. This application will test the hypothesis that LPS PC induces brain engraftment of protective monocytic cells that ameliorate ischemic brain injury either directly or by modulating the immune response to cerebral ischemia. To this end, we will determine (a) the origin of neuroprotective monocytic subtypes, (b) the molecular factors driving their entry into the brain, and (c) the mechanisms by which they confer neuroprotection. Furthermore, we will determine whether these cells can be adoptively transferred to protect animals from experimental stroke with a clinically relevant therapeutic window. These goals will be achieved using a mouse model of transient focal cerebral ischemia with assessment of histological and neurological outcome. The effect of LPS PC on immune cell populations will be assessed by flow cytometry.