IL1 and hypoxic-ischemic insults

描述（由申请人提供）：脑缺血（即中风）引起的脑损伤是一个主要的公共卫生问题。多达50%的中风引起的脑损伤发生在损伤的主要焦点之外，组织破坏的过程持续数小时至数天。现在很明显，炎症因子有助于这种延迟的病理生理学。具体来说，研究表明，细胞因子，白细胞介素1 <$（IL-1 <$），是上调后，实验和临床中风，而其他研究牵连它在损伤的进展。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，我们开发了一个可靠的和可重复的体外模型系统，利用混合的神经元/星形胶质细胞皮质细胞培养。在该模型中，通过外源性添加IL IL-1和通过剥夺细胞的氧气诱导的神经元损伤来模拟IL-1的内源性产生。我们发现预处理？而不是同时或治疗后？该细胞因子显著增强了通过剥夺混合鼠皮质细胞培养物的氧而诱导的神经元细胞死亡。IL-1的作用是浓度依赖性的，可以完全抑制重组IL-1受体拮抗剂，表明通过IL-1受体I型（IL 1 R1）的信号转导参与。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通过代谢型谷氨酸受体1（但不是mGluRS）的药理学拮抗作用完全阻止。这与不受mGluRI受体拮抗作用影响的纯缺氧神经元损伤形成鲜明对比。最后，我们发现IL-1诱导的损伤的增强依赖于星形胶质细胞中IL 1 R1的表达，而神经元中信号的丢失则没有影响。因此，这项为期五年的研究计划的目标是：1）确定IL-1 β信号传导与mGluRI信号传导在功能上协同作用以增强缺氧神经元损伤的分子机制; 2）确定负责介导IL-1增强效应的星形胶质细胞因子; 3）评估去除IL-1 β是否会导致缺氧神经元损伤。信号转导可有效地预防/减轻由海马直接注射NMDA和/或大脑中动脉闭塞引起的在体海马损伤。这些事件的定义的改善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.