TGFbeta signaling, reactive astrogliosis and function after stroke

TGFbeta 信号传导、反应性星形胶质细胞增生和中风后的功能

• 批准号: 8453563
• 负责人: MARION S BUCKWALTER
• 金额: $ 6.45万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8453563
• 关键词: Ablation; Acute; Affect; Astrocytes; Biological Assay; Brain; Brain Injuries; CCL2 gene; CCL7 gene; Caring; Cause of Death; Cells; Data; Exhibits; Genetic; Glial Fibrillary Acidic Protein; Glucose; Immune; Immune response; Immune system; Immunohistochemistry; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Injury; Ischemia; Lead; Length; Measures; Medical; Molecular; Mus; Oxygen; Pathway interactions; Patients; Pattern; Pharmaceutical Preparations; Phenotype; Plasma; Process; Recovery; Recovery of Function; Reporter; Resolution; Role; Signal Transduction; Specificity; Staining method; Stains; Stroke; Testing; Time; Transforming Growth Factor beta; United States; astrogliosis; base; behavior test; brain cell; cell type; chemokine; cytokine; deprivation; disability; functional outcomes; immune function; improved; in vivo; inhibitor/antagonist; injured; insight; kinase inhibitor; macrophage; mouse model; neuroinflammation; neutrophil; public health relevance; research study; response; response to injury; small molecule; stroke recovery

DESCRIPTION (provided by applicant): Stroke is the leading cause of long-term disability in the United States. Although acute revascularization therapies can be used to abort or reduce stroke burden, there are currently no drugs that improve recovery after a stroke has happened. The inflammatory response is a promising target for such therapies as it occurs in the days and weeks after a stroke and can be both detrimental and beneficial. A major unanswered question is how the injured brain modulates immune responses, and if there are molecular pathways that can be utilized to exert beneficial or limit detrimental effects on functional recovery via modulating the overall immune response. Astrocytes are a key component of the brain's injury response - so-called "reactive astrocytes" are ubiquitous after brain injury. They are also increasingly recognized as key components of the brain's innate immune system. We propose to ask if Transforming Growth Factor Beta (TGF¿) signaling in astrocytes modulates inflammation after stroke because it is a master regulator of immune responses. TGF¿ can resolve immune responses after injury and drive immune cell phenotypes towards less inflammatory states. Our preliminary experiments show that TGF¿ signaling is increased in the brain after stroke, persists for weeks, and occurs in reactive astrocytes. To test if TGF¿'s function in reactive astrocytes mirror its role in other types of immune cells we constructed mice in which TGF¿ signaling is decreased only in astrocytes. We have found that primary astrocytes from these mice exhibit a more "pro-inflammatory" phenotype after oxygen- glucose deprivation, and the mice themselves demonstrate increased inflammatory responses after stroke. Based on this data we hypothesize that after stroke, TGF¿ signaling (1) occurs in reactive astrocytes, (2) limits the inflammatory response, and (3) improves functional recovery. We plan to test our hypothesis in three Specific Aims. In Aim 1 we will use reporter mice and immunohistochemistry to determine patterns of TGF¿ signaling after stroke. We hypothesize that there are increased responses to TGF-¿ for weeks after stroke, and that reactive astrocytes are responding to TGF¿ after stroke. In Aim 2 we will test the function of astrocytic TGF¿ signaling in the neuroinflammatory response to ischemia, using genetic and pharmacological approaches and in vivo and in vitro experiments to target TGF¿ signaling in astrocytes. We hypothesize that astrocytic TGF¿ signaling drives resolution of the immune response to stroke. In Aim 3 we will use a genetic mouse model to ask if stroke-induced astrocytic TGF¿ signaling is beneficial or detrimental for functional recovery. We predict that astrocytic TGF¿ signaling improves recovery from stroke. With the completion of the proposed experiments we will have defined the length and cell specificity of TGF¿ responses after stroke. We will gain insight into how astrocytes influence the immune response to stroke, and into the functional diversity of reactive astrocytes. Our findings may lead to therapies that will target the brain's immune responses and benefit patients who present for medical care in the days after stroke. PUBLIC HEALTH RELEVANCE: Stroke is the third leading cause of death in the US, and a leading cause of disability, and there are currently no drugs that improve recovery after stroke. Neuroinflammation affects many processes important for recovery from stroke and modulating neuroinflammation is therefore likely to be a way we can improve recovery from stroke. In this application we propose to study the effects of a master regulator of neuroinflammation, transforming growth factor beta, to determine how its effects in astrocytes can be manipulated to increase successful recovery from stroke.

描述（由申请人提供）：中风是美国长期残疾的主要原因，尽管急性血运重建疗法可用于中止或减轻中风负担，但目前没有药物可以改善中风发生后的恢复。炎症反应是此类疗法的一个有希望的目标，因为它发生在中风后的几天和几周内，既可能带来痛苦，也可能有益。一个主要的未解答的问题是受损的大脑如何调节免疫反应，以及是否存在可以调节免疫反应的分子途径。是用于通过调节整体免疫反应对功能恢复产生有益或限制有害影响，星形胶质细胞是大脑损伤反应的关键组成部分——所谓的“反应性星形胶质细胞”在脑损伤后无处不在，它们也越来越被认为是关键组成部分。我们建议询问星形胶质细胞中的转化生长因子β (TGF¿) 信号是否可以调节中风后的炎症，因为它是免疫反应的主要调节剂。我们的初步实验表明，TGF¿中风后大脑中的信号传导增强，持续数周，并发生在反应性星形胶质细胞中。在反应性星形胶质细胞中的功能反映了它在其他类型免疫细胞中的作用，我们构建了小鼠，其中 TGF¿我们发现，这些小鼠的原代星形胶质细胞在缺氧-葡萄糖后表现出更“促炎症”的表型，并且小鼠本身在中风后表现出炎症反应增加。中风，TGF¿信号传导（1）发生在反应性星形胶质细胞中，（2）限制炎症反应，（3）改善功能恢复我们计划在三个具体目标中测试我们的假设，我们将使用报告小鼠和免疫组织化学来确定信号传导的模式。转化生长因子??我们勇敢地承认，对 TGF-¿ 的反应有所增加。中风后数周，反应性星形胶质细胞对 TGF 做出反应？在目标 2 中，我们将测试星形细胞 TGF 的功能。使用遗传和药理学方法以及体内和体外实验来靶向缺血的神经炎症反应中的信号转导我们勇敢地面对星形胶质细胞中的 TGF¿信号传导驱动中风免疫反应的解决 在目标 3 中，我们将使用遗传小鼠模型来探究中风是否会诱导星形胶质细胞 TGF？我们预测星形细胞 TGF¿随着所提出的实验的完成，我们将确定 TGF 的长度和细胞特异性。我们将深入了解星形胶质细胞如何影响中风的免疫反应，以及反应性星形胶质细胞的功能多样性，我们的研究结果可能会导致针对大脑免疫反应的治疗，并使就医的患者受益。中风后几天。 公共健康相关性：中风是美国第三大死亡原因，也是导致残疾的主要原因，目前没有药物可以改善中风后的恢复，神经炎症会影响中风恢复的许多重要过程，因此可能会调节神经炎症。在此应用中，我们建议研究神经炎症的主要调节剂转化生长因子β的作用，以确定如何操纵其在星形胶质细胞中的作用。增加中风的成功康复。