Neuroprotection by Post-stroke Activation of the ACE2-Ang-(1-7)-Mas Axis

中风后 ACE2-Ang-(1-7)-Mas 轴激活的神经保护作用

• 批准号: 8783336
• 负责人: Douglas M Bennion
• 金额: --
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-11 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8783336
• 关键词: Acute; Affect; American; Angiotensin II; Angiotensins; Animal Model; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Antibodies; Binding; Brain; CCL4 gene; Caring; Cause of Death; Cerebrovascular Circulation; Cerebrum; Clinical; Clinical Trials; Cytokine Signaling; Data; Dose; Effectiveness; Endothelin-1; Ensure; Enzymes; Event; Figs - dietary; Future; Goals; Hour; Human; Imagery; Infarction; Inflammation; Inflammatory; Intraperitoneal Injections; Ischemic Stroke; Label; Laboratories; Light; Magnetic Resonance Imaging; Measures; Mediating; Methods; Microglia; Middle Cerebral Artery Occlusion; Modeling; Mus; Nervous System Physiology; Neurologic; Neurons; Patients; Peptidyl-Dipeptidase A; Perfusion; Peripheral; Pharmaceutical Preparations; Process; Production; Publishing; Rattus; Relative (related person); Renin-Angiotensin System; Reproducibility of Results; Research; Rodent; Role; Signal Transduction; Signaling Molecule; Stroke; System; Techniques; Testing; Therapeutic; Time; Translating; Translational Research; Translations; United States; angiotensin I (1-7); base; clinically relevant; cytokine; design; disability; inflammatory marker; minimally invasive; neuroprotection; novel; novel strategies; overexpression; post stroke; pre-clinical; protective effect; public health relevance; receptor; receptor binding; research study; stroke therapy; therapeutic target

DESCRIPTION (provided by applicant): As the 4th leading cause of death in the United States, stroke affects nearly every American in some way. Despite extensive research, there are few therapies for treating stroke after onset, and there are no approved treatments to specifically counteract the inflammatory stroke damage that occurs within the hours and days after the ischemic event. This study is designed to test a recently discovered target for the treatment of acute ischemic stroke. Over the past several decades, it has become apparent that over-activation of the classical renin angiotensin system (RAS), which includes angiotensin II binding to its type 1 receptor, is detrimental in stroke. More recently, a protective axis of the RAS, the angiotensin converting enzyme 2 - angiotensin-(1-7) - Mas [ACE2-Ang-(1-7)-Mas] axis, has been shown to have opposite effects that are protective in stroke. In this study, this protective axis will be targeted using methods that are clinically-feasible and at post-stroke time points that mimic what an actual stroke patient might receive following stroke onset. In the first specific aim, several animal models of stroke will be used to test the neuroprotective effects of diminazene aceturate (DIZE), an activator of the ACE2. Efficacy will be evaluated in rodent stroke models, with post-stroke administration of different doses of DIZE at +4 hrs, +24 hrs, and +48 hrs following stroke, with and without concurrent administration of the Mas receptor antagonist A-779. At one day and three days after the stroke is induced, brains will be analyzed to determine the extent of the protective effects of this drug treatment. The importance of the ACE2 enzyme within this axis will be evaluated utilizing the Cre/lox system in mice to test the specific hypothesis that ACE2 overexpression in stroke will result in neuroprotection. Endpoint measures for this aim include infarct size, neurological function, brain levels of Ang-(1-7), and markers of inflammation. In the second specific aim, experiments have been designed to better understand the mechanisms by which DIZE induces neuroprotection in stroke. In particular, they will test whether DIZE induces neuroprotection by 1) increasing levels of cerebral blood flow, and 2) mediating activation of inflammatory and anti-inflammatory microglia. Cerebral blood flow will be measured using MRI during baseline and stroke conditions to evaluate whether DIZE induces protection in a flow dependent manner. Antibody labeling will facilitate visualization of microglial subtype activation following stroke. The endpoint measures to determine the effectiveness of post-stroke DIZE administrations on these processes include MRI measures of cerebral blood flow and relative levels of microglial subtype activation. These studies will have a positive impact and clinical relevance since they will inform future animal studies and human clinical trials regarding this protective axis as therapeutic target for the acute treatment of ischemic stroke.

描述（由申请人提供）： 作为美国第四大死亡原因，中风以某种方式影响着几乎每个美国人。尽管进行了广泛的研究，但很少有治疗中风发作后的治疗方法，并且没有批准的治疗方法来专门抵消缺血事件后数小时和数天内发生的炎性中风损伤。本研究旨在测试最近发现的急性缺血性卒中治疗靶点。在过去的几十年中，已经变得明显的是，过度激活经典的肾素血管紧张素系统（RAS），其中包括血管紧张素II结合其1型受体，是有害的中风。最近，RAS的保护轴，血管紧张素转换酶2 -血管紧张素-（1-7）- Mas [ACE 2-Ang-（1-7）-Mas]轴，已显示具有在中风中保护的相反作用。在这项研究中，将使用临床可行的方法在卒中后时间靶向这一保护轴 这些点模拟了实际中风患者在中风发作后可能接受的治疗。在第一个具体目标中，将使用几种中风动物模型来测试ACE 2的激活剂--乙酰氨基二氮烯（DIZE）的神经保护作用。将在啮齿动物中风模型中评价功效，中风后在中风后+4小时、+24小时和+48小时给予不同剂量的DIZE，同时给予和不同时给予Mas受体拮抗剂A-779。在诱发中风后的第一天和第三天，将分析大脑以确定这种药物治疗的保护作用的程度。将利用小鼠中的Cre/lox系统来评估ACE 2酶在该轴内的重要性，以测试中风中ACE 2过表达将导致神经保护的特定假设。该目的的终点指标包括梗死面积、神经功能、脑内Ang-（1-7）水平和炎症标志物。在第二个具体目标中，设计了实验以更好地理解DIZE诱导中风神经保护的机制。特别是，他们将测试DIZE是否通过1）增加脑血流量水平和2）介导炎症和抗炎小胶质细胞的激活来诱导神经保护。将在基线和卒中条件下使用MRI测量脑血流量，以评价DIZE是否以流量依赖性方式诱导保护。抗体标记将有助于中风后小胶质细胞亚型激活的可视化。确定卒中后DIZE给药对这些过程的有效性的终点指标包括脑血流量的MRI指标和小胶质细胞亚型活化的相对水平。这些研究将有 积极的影响和临床相关性，因为它们将告知未来的动物研究和人类临床试验，关于该保护轴作为缺血性卒中急性治疗的治疗靶点。