Deciphering the mechanism through which BRD4 mutations contribute to the neurodevelopmental disorder

表观遗传蛋白，包括组蛋白翻译后修饰和染色质重塑蛋白的编写者和读取者，在受控的组织特异性基因表达调控中发挥着重要作用。组蛋白赖氨酸的乙酰化是最丰富的修饰之一，可以改变染色质的结构和功能。赖氨酸乙酰化和去乙酰化之间的微妙平衡对中枢神经系统的正常功能至关重要。扰乱组蛋白乙酰化途径的基因突变会导致许多神经发育障碍，需要详细研究乙酰化途径在中枢神经系统中的具体作用。最近，我们发现编码组蛋白乙酰化阅读器蛋白BRD4的基因突变会导致神经发育障碍。然而，这种编码表观遗传因子的基因突变如何导致特定的神经发育障碍尚不清楚。我们的目标是研究BRD4的突变如何导致中枢神经系统的发育和功能改变。我们将首先在人类神经细胞类型中识别受BRD4调控的基因。然后，我们将识别受BRD4调控的神经元特异性增强子，并将这些增强子与BRD4中缺失或突变时调节失调的靶基因联系起来。接下来，我们将通过在迷你脑器官模型中执行单细胞转录和表观遗传学改变，来调查BRD4患者特有的突变是如何导致转录程序改变的。此外，我们将测试表观遗传药物在挽救由于BRD4突变而改变的大脑发育表型和功能方面的效果。总体而言，这项提议旨在揭示BRD4在人脑发育和功能中的作用，以及BRD4突变如何导致特定的神经发育障碍。

Epigenetic proteins, including writers and readers of histone posttranslational modifications and chromatin remodelling proteins, play an essential role in the controlled tissue-specific regulation of gene expression. Acetylation of histone lysines is one of the most abundant modifications which alters chromatin structure and function. A delicate balance between lysine acetylation and deacetylation is essential for the normal functioning of the central nervous system. Gene mutations that perturb the histone acetylation pathway cause many neurodevelopmental disorders, warranting detailed investigation into the specific role of the acetylation pathway in the central nervous system. Recently we have discovered that mutations in gene encoding histone acetylation reader protein BRD4 lead to a neurodevelopmental disorder. However, it is not clear how mutations in this gene encoding epigenetic factor lead to specific neurodevelopmental disorders. We aim to investigate how mutations in BRD4 cause altered development and functioning of the central nervous system. We will first identify genes regulated by BRD4 in human neuronal cell types. We will then identify neuronal-specific enhancers regulated by BRD4 and link these enhancers to target genes that are dysregulated upon depletion or mutation in BRD4. Next, we will investigate how patient-specific mutations in BRD4 cause an altered transcriptional programme by performing single-cell transcriptomics and epigenetic alterations in the mini-brain organoid model. Furthermore, we will test the efficacy of epigenetic drugs in rescuing the altered brain development phenotype and functioning due to BRD4 mutations. Overall, this proposal aims to uncover the role of BRD4 in human brain development and function and how BRD4 mutations lead to specific neurodevelopmental disorders.