Therapeutic Targeting of the Class IB PI3-Kinase Gamma for Treatment of Acute Ischemic Stroke

描述（由申请人提供）：IB类pi3 -激酶γ治疗急性缺血性脑卒中的治疗靶点。重组tPA仍然是FDA批准的唯一一种治疗缺血性卒中的最有益的干预措施。然而，tPA的临床应用由于其狭窄的治疗窗口和出血转化（HT）的风险增加而受到限制。在本研究中，我们假设AS605240单独或联合tPA治疗性抑制PI3Kg可预防缺血和tPA诱导的脑损伤和HT，并增加tPA治疗缺血性卒中的治疗窗口期。我们的想法的分子基础是PI3Kg的基因缺失不仅减少脑卒中引起的血脑屏障破坏和组织梗死，而且几乎完全阻断脑卒中后6小时给予tPA引起的脑出血。我们的数据是有希望的，并表明PI3Kg在tpa诱导的HT和缺血性卒中后脑损伤中的关键作用。此外，我们的试点数据显示，AS605240抑制PI3Kg显著保护脑损伤，并减少栓塞性脑卒中后缺血性脑中的纤维蛋白沉积/血栓形成。这些令人兴奋的初步数据表明，PI3Kg可能是治疗急性缺血性卒中的一个有希望的治疗靶点。在本应用程序中，我们建议开发一个

DESCRIPTION (provided by applicant): Therapeutic targeting of the class IB PI3-kinase gamma for treatment of acute ischemic stroke. Recombinant tPA remains the only FDA approved and the most beneficial proven intervention for treatment of ischemic stroke. However, clinical use of tPA is limited due to its narrow therapeutic window and increased risk of hemorrhagic transformation (HT). In this proposal, we hypothesize that therapeutic inhibition of PI3Kg with AS605240, alone or in combination with tPA, protects against the ischemia- and tPA-induced brain injury and HT and increases therapeutic window for tPA treatment of ischemic stroke. The molecular basis for our idea is that genetic deletion of PI3Kg not only reduces stroke-induced BBB disruption and tissue infarction but also almost completely blocked cerebral hemorrhage induced by tPA administered at 6 hours after stroke. Our data are promising and suggest a critical role of PI3Kg in tPA-induced HT and brain injury after ischemic stroke. Further, our pilot data show that inhibition of PI3Kg with AS605240 significantly protects against brain injury and reduces fibrin deposition/thrombosis in the ischemic brain after embolic stroke in rats. These exciting preliminary data suggest that PI3Kg may represent a promising therapeutic target for treating acute ischemic stroke. In this application, we propose to develop a new stroke therapy by therapeutic targeting of PI3Kg with AS605240 for treatment of acute ischemic stroke and to investigate molecular mechanisms underlying the AS605240-mediated beneficial effects. We now propose three aims to investigate this new stroke therapy. In Aim 1, we will determine the effects of AS605240, alone and in combination with tPA, treated at 6 hrs after focal embolic stroke in rats. We will identify the optimal dosage and the extended therapeutic time window for AS605240 alone and in combination with tPA for treatment of acute stroke. Brain infarction, neurological deficits, brain hemorrhage, and animal mortality will be examined 72h after stroke. In Aim 2, we will define the mechanisms that underlie the beneficial effects of AS605240 alone or in combination with tPA in the treatment of acute stroke. BBB damage will be assessed by the spatial and temporal analysis of key BBB proteins and potential correlation with changes in activation/expression of NF-κB, CD147, MMP-9 and/or MMP-3 on cerebral vessels. Thrombus formation in the ischemic brain after stroke will be assessed by analyzing fibrin deposition within and around the cerebral vessel wall and the expression of prothrombotic factors (PAI-1, tissue factor-TF) in the ischemic brain. In Aim 3, we will assess long term outcomes of AS605240 alone and in combination with tPA treated at 6 hrs after embolic stroke. Animals will be followed over 5 weeks with a battery of behavioral tests. At the end, brains are removed for measurements of lesion size, fibrin deposition/thrombosis, cerebral vascular density/potency, and their correlation with the expression of proangiogenic factors (VEGF, Ang-1) and prothrombotic factors (PAI-1, tissue factor-TF). If successful, these proposed experiments should provide new insights of how the class IB PI3Kg signaling contributes to the ischemia- and tPA-induced HT and brain injury and may ultimately yield new therapies to treat acute ischemic stroke and to minimize the adverse effect of tPA on ischemic neurovascular damage, leading to improved long term outcomes after ischemic stroke.