Novel role and mechanisms of histone deacetylases in traumatic brain injury

组蛋白脱乙酰酶在创伤性脑损伤中的新作用和机制

基本信息

批准号：
9613417
负责人：
MICHAEL V L BENNETT
金额：
$ 47.81万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9613417
关键词：
Ablation Bone Marrow Brain Brain Injuries Cerebrum Clinical Cognitive Development Dose Emotional Encephalitis Excision Female Functional disorder Gender Genetic Genetic Transcription HDAC1 gene HDAC2 gene HDAC3 gene Histone Deacetylase Histone Deacetylase Inhibitor Histones In Vitro Inflammation Inflammatory Inflammatory Response Injury Knock-out Lysine Macrophage Activation Mediating Mediator of activation protein Microglia Modeling Molecular Mus Nervous System Physiology Neuronal Injury Neurons Outcome Pharmacology Phenotype Pilot Projects Play Post-Translational Protein Processing Proteins Quality of life Recovery Recovery of Function Rehabilitation therapy Resolution Role STAT1 protein Sensorimotor functions Signal Pathway Signal Transduction Stretching Tamoxifen Testing Therapeutic Time Tissues Traumatic Brain Injury aged brain remodeling brain repair brain tissue cognitive function controlled cortical impact functional group gray matter improved in vitro Model in vivo inhibitor/antagonist injury and repair macrophage male member neurobehavioral neuroinflammation neuroprotection neuropsychiatry neurorestoration neurotoxicity new therapeutic target non-histone protein novel novel therapeutics prevent response sex subcutaneous therapeutic evaluation therapeutic target tool white matter young adult

项目摘要

Emerging evidence implicates a pivotal role of cerebral inflammation in the pathophysiology of traumatic brain injury (TBI). Following TBI, microglia/macrophages may assume distinct pro-inflammatory or inflammation- resolving phenotypes, which potentiate brain injury or facilitate brain repair, respectively. The intracellular molecular switches that determine microglial/macrophage functional phenotypes after TBI are poorly understood. Identifying such molecular mechanisms may reveal novel targets to tune microglia/macrophages toward the reparative inflammation-resolving phenotype and improve long-term TBI outcomes. Histone deacetylases (HDACs) catalyze the removal of acetyl groups from histone and non-histone proteins, thereby regulating not only gene transcription but also the activity of various proteins through post-translational modifications. Previous studies by us and others demonstrate that pan-inhibitors of Class I HDACs (HDAC1, 2, 3, 8) mitigate brain inflammation and improve neurological functions after TBI. However, it is imperative to elucidate the role of different HDAC subtypes, in order to focus on specific therapeutic targets without disrupting the beneficial functions of some HDACs in post-injury brain repair. To date, the HDAC subtype responsible for protection against TBI is unknown. It is also not known if the cellular/molecular mechanisms underlying HDAC inhibitor-afforded protection involve the alteration of microglial/macrophage phenotype. Our pilot studies show for the first time that: 1) Microglia/macrophage-specific knockout (mKO) of HDAC3, but not HDAC1 or HDAC2, improves neurobehavioral outcomes after TBI. 2) HDAC3 mKO improves gray and white matter integrity, and mitigates neuroinflammation after TBI. 4) HDAC3 inhibition ameliorates pro- inflammatory microglia-mediated neurotoxicity after neuronal stretch injury (NSI), an in vitro TBI model. 5) HDAC3 inhibition reduces the activation of signal transducer and activator of transcription 1 (STAT1), a key molecule that mediates pro-inflammatory responses in microglia/macrophages. 6) Subcutaneous delivery of RGFP966, a brain-penetrant, potent, and specific HDAC3 inhibitor, ameliorates inflammation and sensorimotor deficits after TBI. Given these observations, we propose three specific aims to test the novel hypothesis that genetic or pharmacological ablation of HDAC3 provides neuroprotection and improves brain repair and long-term outcomes after TBI by promoting inflammation-resolving microglial/macrophage responses. Aim 1: Test if HDAC3 mKO improves gray and white matter integrity and long-term neurological functions after TBI. Controlled cortical impact (CCI) will be induced in mice of both sexes with tamoxifen-inducible HDAC3 knockout in microglia/macrophages. Aim 2: Test if genetic knockout of the HDAC3-STAT1 signaling pathway shifts microglia/macrophages toward the beneficial and inflammation-resolving phenotype after TBI. Aim 3: Test the therapeutic potential of the specific HDAC3 inhibitor RGFP966 in resolution of inflammation and improvement of long-term TBI outcomes in young adult and aged mice of both genders.

新的证据表明脑炎症在脑外伤的病理生理学中发挥着关键作用损伤（TBI）。 TBI 后，小胶质细胞/巨噬细胞可能具有明显的促炎或炎症作用。解决表型，分别加剧脑损伤或促进脑修复。细胞内的决定 TBI 后小胶质细胞/巨噬细胞功能表型的分子开关很差明白了。识别此类分子机制可能会揭示调节小胶质细胞/巨噬细胞的新靶点朝向修复性炎症消退表型并改善长期 TBI 结局。组蛋白脱乙酰酶 (HDAC) 催化组蛋白和非组蛋白中乙酰基的去除，从而不仅调节基因转录，还通过翻译后调节各种蛋白质的活性修改。我们和其他人之前的研究表明，I 类 HDAC 的泛抑制剂（HDAC1、2、 3, 8) 减轻脑损伤后的脑部炎症并改善神经功能。然而，当务之急是阐明不同 HDAC 亚型的作用，以便专注于特定的治疗靶点，而无需破坏某些 HDAC 在损伤后大脑修复中的有益功能。迄今为止，HDAC 亚型负责预防 TBI 的作用尚不清楚。也不知道细胞/分子机制是否 HDAC 抑制剂提供的潜在保护涉及小胶质细胞/巨噬细胞表型的改变。我们的初步研究首次表明：1) HDAC3 的小胶质细胞/巨噬细胞特异性敲除 (mKO)，但是不是 HDAC1 或 HDAC2，可以改善 TBI 后的神经行为结果。 2) HDAC3 mKO 改善灰色和白质完整性，并减轻 TBI 后的神经炎症。 4) HDAC3 抑制改善亲神经元牵张损伤（NSI）后炎症小胶质细胞介导的神经毒性，体外 TBI 模型。 5） HDAC3 抑制会降低信号转导子和转录激活子 1 (STAT1) 的激活，这是一个关键介导小胶质细胞/巨噬细胞促炎症反应的分子。 6) 皮下输送 RGFP966 是一种脑渗透性、强效且特异性的 HDAC3 抑制剂，可改善炎症和感觉运动 TBI 后的赤字。鉴于这些观察结果，我们提出了三个具体目标来检验新假设： HDAC3 的遗传或药物消融可提供神经保护并改善大脑修复通过促进炎症消解的小胶质细胞/巨噬细胞反应来实现 TBI 后的长期结果。目标 1：测试 HDAC3 mKO 后是否能改善灰质和白质完整性以及长期神经功能创伤性脑损伤。他莫昔芬诱导的 HDAC3 将在雌雄小鼠中诱导受控皮质影响 (CCI) 小胶质细胞/巨噬细胞的敲除。目标 2：测试 HDAC3-STAT1 信号通路是否被基因敲除 TBI 后将小胶质细胞/巨噬细胞转向有益且可消炎的表型。目标 3：测试特定 HDAC3 抑制剂 RGFP966 在解决炎症方面的治疗潜力改善年轻成年和老年小鼠的长期 TBI 结局。