IL1 and hypoxic-ischemic insults

IL1 和缺氧缺血性损伤

• 批准号: 7148482
• 负责人: SANDRA J HEWETT
• 金额: $ 29.97万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-18 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7148482
• 关键词: injury; receptor; stroke

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 1beta (IL-1beta), 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-1beta 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-1beta is simulated by exogenous addition of IL-1beta 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-1beta 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-1beta -mediated enhancement of hypoxic-neuronal injury can be completely prevented by pharmacological antagonism of metabotropic glutamate receptor 1 (but not mGluR5). This is in stark contrast to a pure hypoxic neuronal injury which is unaffected by mGluR1 receptor antagonism. Finally, we found that the enhancement of injury induced by IL-1beta 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 IL1beta signaling functionally synergizes with mGluR1 signaling to enhance hypoxic neuronal injury; 2) to determine the astrocytic factor or factors responsible for mediating the IL-1beta enhancing effect; and 3) to assess whether removal of IL-1beta 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.

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 β (il -1 β)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 β参与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。在该模型中，通过外源性添加il -1 β和缺氧引起的神经元损伤来模拟内源性il -1 β的产生。我们发现，预处理-而不是同时或后处理-与这种细胞因子显著增强了由剥夺混合小鼠皮质细胞培养的氧诱导的神经元细胞死亡。IL-1 β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 β介导的缺氧神经元损伤的增强可以通过代谢性谷氨酸受体1（但不是mGluR5）的药理拮抗来完全预防。这与纯缺氧神经元损伤形成鲜明对比，后者不受mGluR1受体拮抗剂的影响。最后，我们发现il -1 β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，这项为期五年的研究计划的目标是：1)确定il - 1 β信号与mGluR1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介导il -1 β增强作用的因子；3)评估去除il -1 β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。