Degrading BET Proteins is Neuroprotective in Ischemic Stroke

项目描述 中风后的神经炎症显著促进神经元细胞死亡。溴结构域和额外 末端结构域（BET）蛋白是炎症基因转录所必需的。有四种BET蛋白质： BRD 2、BRD 3、BRD 4和BRDT。BRD 2和BRD 4是丰富的并且普遍表达。BRD3 在包括脑在内的大多数组织中表达非常低，并且BRDT是睾丸特异性的。BET蛋白质含有 两个与乙酰化赖氨酸相关的保守溴结构域和一个末端外结构域。打赌 蛋白质具有不同的作用，包括染色质重塑、组蛋白乙酰转移酶活性， 支架招募转录因子;他们夫妇染色质重塑与转录。我们假设 BET阻断将提供一种多管齐下的方法来减少中风后的细胞死亡。BRD 2正常 抑制过氧化物酶体增殖物激活物γ（过氧化物酶体增殖物激活物γ）的活性，这具有抗炎作用，所以我们 预期抑制BRD 2将增加抗炎基因的转录。BRD 2敲除还 降低核因子-κB（NF-κB）活化，NF-κB是促炎基因的主要调节因子 在stroke中转录。BRD 4作为NF-κB共激活剂，因此我们预测BRD 2和BRD 4 抑制将减少缺血性脑中的促炎基因转录。此外，由于BRD 2 和BRD 4组成性抑制核因子（红细胞衍生2）相关因子（Nrf 2），该因子对于 抗氧化基因转录，我们预期BRD 2/4抑制可增加抗氧化基因的表达， 减少氧化应激。关于BET蛋白在中风中的作用知之甚少，但我们的初步数据显示， 显示BET抑制减少中风啮齿动物模型中的梗塞。我们的长期目标是减少 通过限制继发性炎症的影响来传播中风损伤。我们的假设是BET 通过限制继发性炎症的有害作用，抑制在缺血性中风中具有神经保护作用。 我们的主要目的是确定BET抑制在缺血性卒中中具有保护作用的机制。在 目的1，我们将使用dBET 1（一种蛋白水解酶， 靶向降解BET蛋白的嵌合体）。我们将利用缺血性中风的雄性小鼠， 研究BET阻断对梗死面积和长期行为结果的影响。在目标2中，我们将 确定BET阻断对中风诱导的神经炎症的影响。本项目将提供 BET蛋白如何促进缺血性卒中后继发性损伤的机制见解。这些数据将 产生积极的影响，因为它将为未来开发新的治疗药物提供坚实的基础。 针对BET蛋白的策略，以减少中风损伤。

PROJECT DESCRIPTION Neuroinflammation after stroke significantly contributes to neuronal cell death. Bromodomain and Extra Terminal Domain (BET) proteins are essential to inflammatory gene transcription. There are four BET proteins: BRD2, BRD3, BRD4, and BRDT. BRD2 and BRD4 are abundant and ubiquitously expressed. BRD3 expression is very low in most tissues including the brain, and BRDT is testis specific. BET proteins contain two conserved bromodomains that associate with acetylated lysines, and an extraterminal domain. BET proteins have varied effects including chromatin remodeling, histone acetyltransferase activity, and as scaffolds to recruit transcription factors; they couple chromatin remodeling with transcription. We hypothesize that BET blockade will provide a multipronged approach to reducing cell death after stroke. BRD2 normally represses peroxisome proliferator activator γ (PPARγ) activity, which has an anti-inflammatory effect, so we expect that inhibiting BRD2 will increase anti-inflammatory gene transcription. BRD2 knockdown also decreases nuclear factor-κB (NF-κB) activation, which is a major regulator of pro-inflammatory gene transcription in stroke. BRD4 acts as an NF-κB co-activator, therefore we predict that BRD2 and BRD4 inhibition will decrease pro-inflammatory gene transcription in the ischemic brain. Furthermore, because BRD2 and BRD4 constitutively inhibit nuclear factor (erythroid-derived 2)-related factor (Nrf2) which is essential to antioxidant gene transcription, we expect BRD2/4 inhibition to increase expression of antioxidant genes, reducing oxidative stress. Little is known regarding the role of BET proteins in stroke, but our preliminary data shows that BET inhibition reduces infarct in a rodent model of stroke. Our long-term goal is to reduce the spread of stroke damage by limiting the effects of secondary inflammation. Our hypothesis is that BET inhibition is neuroprotective in ischemic stroke by limiting the deleterious effects of secondary inflammation. Our main objective is to determine the mechanism by which BET inhibition is protective in ischemic stroke. In Aim 1, we will determine the neuroprotective effect of BET blockade after ischemia using dBET1 (a proteolysis- targeting chimera that degrades BET proteins). We will utilize male mice subjected to ischemic stroke to investigate the effects of BET blockade on infarct size and long-term behavioral outcomes. In Aim 2, we will determine the effects of BET blockade on stroke-induced neuroinflammation. This project will provide mechanistic insights into how BET proteins contribute to secondary injury after ischemic stroke. These data will yield a positive impact as it will provide a strong foundation for future development of novel therapeutic strategies targeting BET proteins to reduce stroke damage.