IL1 and hypoxic-ischemic insults

描述（由申请人提供）：脑缺血引起的脑损伤（即中风）是一个主要的公共卫生问题。中风造成的脑损伤中，多达50%发生在主要损伤灶之外，组织破坏的过程持续数小时至数天。现在很明显，炎症因素有助于这种延迟的病理生理。具体来说，研究表明细胞因子，白细胞介素1¿（IL-1¿）在实验和临床中风后上调，而其他研究表明它与损伤的进展有关。然而，IL-1¿导致神经元细胞死亡的细胞和分子途径尚未确定。这主要是由于缺乏合适的体外模型来评估这些机制。因此，我们开发了一种可靠的、可重复的体外模型系统，利用混合神经元/星形胶质细胞皮层细胞培养。在这个模型中，内源性IL-1 -¿的产生通过外源性添加IL-1 -¿和剥夺细胞氧诱导的神经元损伤来模拟。我们发现预处理？但不是同时或治疗后？该细胞因子显著增强了缺氧培养的混合小鼠皮质细胞诱导的神经元细胞死亡。IL-1¿的作用呈浓度依赖性，可被重组IL-1受体拮抗剂完全抑制，表明通过IL-1受体I型（IL1R1）的信号传导参与其中。此外，我们发现这种IL-1介导的缺氧神经元损伤的增强可以完全通过代谢性谷氨酸受体1（而不是mGluRS）的药理拮抗来预防。这与纯缺氧神经元损伤形成鲜明对比，后者不受mGluRI受体拮抗剂的影响。最后，我们发现IL-1 -¿诱导的损伤增强依赖于il - 1r1的星形细胞表达，而神经元信号的丢失则没有影响。因此，这个五年研究计划的目标是：1)确定IL1p信号与mGluRI信号协同增强缺氧神经元损伤的分子机制；2)确定星形细胞因子或负责介导IL-1增强效应的因子；3)评估去除IL-1信号是否能有效预防/改善海马直接注射NMDA和/或大脑中动脉闭塞引起的体内海马损伤。改善这些事件的定义可能导致新的治疗策略的发展，旨在减轻中风后神经元破坏的进展。

DESCRIPTION (provided by applicant): Injury to the brain caused by cerebral ischemia (i.e. stroke) is a major public health concern. As much as 50% of the brain damage incurred by stroke occurs outside of the primary focus of damage with the process of tissue destruction continuing for hours to days. It is now apparent that inflammatory factors contribute to this delayed pathophysiology. Specifically, studies demonstrate that the cytokine, interleukin 1¿ (IL-1¿), is upregulated following experimental and clinical stroke while additional studies implicate it in the progression of injury. However, the cellular and molecular pathway(s) by which IL-1¿ contributes to neuronal cell death have yet to be identified. This is largely due to the lack of suitable in vitro models in which to assess these mechanisms. Therefore, we developed a reliable and reproducible in vitro model system utilizing mixed neuronal/astrocyte cortical cell cultures. In this model, endogenous production of IL-1¿ is simulated by exogenous addition of IL IL-1¿ and neuronal injury induced by depriving cells of oxygen. We found that pre-treatment? but not concurrent or post-treatment? with this cytokine dramatically potentiated neuronal cell death induced by depriving mixed murine cortical cell cultures of oxygen. The effect of IL-1¿ was concentration-dependent and could be completely inhibited by the recombinant IL-1 receptor antagonist, indicating that signaling through the IL-1 receptor type I (IL1R1) was involved. Further, we found this IL-1¿ -mediated enhancement of hypoxic-neuronal injury can be completely prevented by pharmacological antagonism of metabotropic glutamate receptor 1 (but not mGluRS). This is in stark contrast to a pure hypoxic neuronal injury which is unaffected by mGluRI receptor antagonism. Finally, we found that the enhancement of injury induced by IL-1¿ was dependent on astrocytic expression of IL1R1 whereas loss of signaling in neurons had no effect. Thus, the objectives of this five year research plan are to 1) determine the molecular mechanism(s) by which IL1p signaling functionally synergizes with mGluRI signaling to enhance hypoxic neuronal injury; 2) to determine the astrocytic factor or factors responsible for mediating the IL-1¿ enhancing effect; and 3) to assess whether removal of IL-1¿ signaling can effectively prevent/ameliorate hippocampal injury in vivo induced by direct hippocampal injection of NMDA and/or middle cerebral artery occlusion. Improved definition of these events could lead to the development of new therapeutic strategies designed to attenuate the progression of neuronal destruction following stroke.