Targeting blood-derived integrin signaling after stroke

项目摘要。我们发现雌性小鼠，而不是雄性小鼠，血浆中VTN水平升高 暂时性大脑中动脉闭塞卒中后遗传性VTN缺失导致的组织丢失较少 (MCAO)。VTN的这种女性特有的有害作用可能与女性有关，因为 卒中后的神经功能结局。因此，这项建议的重点是雌性老鼠。我们还发现 VTN在MCAO后渗入脑内，诱导促炎细胞因子的表达。我们的体外和 体内数据表明，VTN通过特定的av整合素发挥作用，也可能通过uPAR发挥作用。整合素激活 粘着斑激酶(FAK)介导的细胞内信号转导。雌性小鼠全身注射FAK 卒中后6h应用抑制剂效果好得多。这些数据表明VTN-整合素-FAK 信号传递导致中风后的组织丢失。目标1将决定是否存在个体差异 MCAO后血液中VTN水平的升高预示着炎症反应和脑组织的丢失。 这可能会提供另一个预测中风预后的标志物，并为开发治疗方法打开新的机会。 我们还将确定VTN和FAK抑制是否通过星形胶质细胞或小胶质细胞FAK起作用，这两个早期 已知对炎症有重大贡献的反应细胞类型。我们会找出最有效的 大脑中动脉阻塞后使用FAK抑制剂进行系统治疗的时间和持续时间，以改善结果，包括 长期的运动功能，并在老年“绝经后”雌性小鼠身上进行测试，因为中风会发生 主要发生在老年人群中，绝经后预后更差。FAK抑制剂目前正在进行临床试验 癌症，而且似乎耐受性很好。目标2将定义特定的VTN受体在多大程度上介导 用药理学和遗传学方法研究VTN对大脑中动脉闭塞后的影响。这一目标将有助于 确定可能比FAK抑制更具选择性的分子靶点和治疗方法。目标3将定义 MCAO后女性大脑中较高的IL-6诱导是否具有神经保护作用，如已报道的 男性，以及中风后血液IL-6水平较高是否有助于VTN的诱导。我们会 还要确定女性性激素是否调节VTN，以及VTN是否抵消保护作用 雌激素和黄体酮的作用。总之，这些研究集中在一种新颖而独特的分子靶标上。 这会导致更糟糕的结果，并将为开发中风后的药物治疗提供新的途径， 也许是专门为女性设计的。

Project Summary. We found that female, but not male, mice have increased plasma vitronectin (VTN) levels and less tissue loss upon genetic VTN deletion after a stroke by temporary middle cerebral artery occlusion (MCAO). This female-specific detrimental role of VTN may be relevant to women because that have worse functional neurological outcomes after stroke. Therefore, this proposal focuses on female mice. We also find that VTN leaks into the brain after MCAO and induces pro-inflammatory cytokine expression. Our in vitro and in vivo data suggest that VTN acts through specific av integrins and possibly through uPAR. Integrins activate intracellular signaling through focal adhesion kinase (FAK). Female mice injected systemically with an FAK inhibitor 6 h after a stroke had better much better outcomes. These data suggest that VTN-Integrin-FAK signaling contributes to tissue loss after stroke. Aim 1 will determine whether individual differences in increased VTN levels in the blood seen after MCAO predict the inflammatory response and loss of brain tissue. This might provide an additional prognostic stroke marker and open new opportunities to develop treatments. We will also determine whether VTN and FAK inhibition act through astroglial or microglial FAK, two early responder cell types with known significant contributions to inflammation. We will identify the most efficacious post-MCAO time and duration of systemic treatments with the FAK inhibitor to improve outcomes, including long-term locomotor function and also test this in aged “post-menopausal” female mice because stroke occurs mainly in older people, with worse outcomes after menopause. FAK inhibitors are currently in clinical trials for cancer and seem to be well tolerated. Aim 2 will define the extent to which the specific VTN receptors mediate the VTN effects, using pharmacological and genetic approaches after MCAO in vivo. This aim will help to identify molecular targets and treatments that may be more selective than FAK inhibition. Aim 3 will define whether the higher IL-6 induction in the female brain after MCAO is neuroprotective, as has been reported for males, and whether blood IL-6 levels, which are higher after stroke, contribute to induction of VTN. We will also determine whether female sex hormones regulate VTN and whether VTN counteracts the protective effects of estrogen and progesterone. Together, these studies focus on a novel and unique molecular target that contributes to worse outcomes, and will provide new avenues for developing drug treatments after stroke, perhaps specifically for women.