Investigating imitation SWI chromatin remodeling complexes in mammalian tissue regeneration

研究哺乳动物组织再生中的仿 SWI 染色质重塑复合物

• 批准号: 10030411
• 负责人: Hao Zhu
• 金额: $ 36.77万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10030411
• 关键词: ATP Hydrolysis; Bromodomain; CRISPR screen; ChIP-seq; Chemicals; Chromatin Remodeling Factor; Clinical; Clinical Drug Development; Colitis; Complex; Data; Disease; Drug Targeting; Enzymes; Epigenetic Process; Excision; Genes; Genetic; Genetic Transcription; Genetic Translation; Genomics; Goals; Health; Hepatocyte; Histones; Human; In Vitro; Inflammatory Bowel Diseases; Intestinal Diseases; Intestines; Knockout Mice; Liver; Liver Cirrhosis; Liver Regeneration; Liver diseases; Long-Term Effects; Malignant Neoplasms; Mammals; Mediating; Modeling; Molecular; Mus; Natural regeneration; Newts; Nucleosomes; Operative Surgical Procedures; Output; Pathway interactions; Pharmacology; Phenotype; Protein Biosynthesis; Proteins; Reader; Recovery; Ribosomal DNA; Ribosomal RNA; Role; SMARCA5 gene; SWI/SNF Family Complex; System; Testing; Tissues; Zebrafish; chromatin remodeling; genome-wide; in vivo; inhibitor/antagonist; mouse model; organ regeneration; regenerative; regenerative therapy; small molecule; small molecule inhibitor; therapeutic target; tissue regeneration; validation studies

PROJECT SUMMARY The potent regenerative capabilities of planaria, newts, and zebrafish are largely lost in mammals, an observation that has a tangible impact on human health. Compromised tissue regeneration likely contributes to disorders such as liver cirrhosis or inflammatory bowel diseases (IBD). Limited regeneration in liver disease settings can also preclude the ability to perform large surgical resections for cancer. The relative lack of regenerative therapies could in part be because discovering new targets is difficult and is dependent on in vivo systems that cannot be replicated in the culture dish. To identify new pathways that can be targeted to enhance regeneration, we established an in vivo CRISPR-Cas9 screening platform to evaluate genes in the mouse liver. Using this high-throughput system, we assessed the impact of 152 genes encoding epigenetic machines such as histone readers, writers, and erasers [2]. This identified two imitation SWI/SNF (ISWI) chromatin remodeling complex subunits encoded by Baz2a and Baz2b, genes that were not previously known to regulate regeneration. The interaction between BAZ2 proteins with the SMARCA5 enzyme defines the nucleolar remodeling complex (NoRC), one of five subtypes of ISWI complexes that uses ATP hydrolysis to remodel nucleosomes, particularly at ribosomal DNA (rDNA) loci [3]. Our validation studies showed that in vivo Cas9 deletion of either Baz2a or Baz2b increased liver regeneration in a hepatocyte repopulation model. Similarly, chemical inhibition of BAZ2A and BAZ2B using the specific bromodomain inhibitor GSK2801 resulted in increased liver regeneration [4]. Moreover, we also found that GSK2801 could promote intestinal recovery in a mouse model of colitis. These data suggest that BAZ2 containing ISWI/NoRC chromatin remodeling complexes are important for organ regeneration and promising therapeutic targets for multiple diseases. Our central hypothesis is that the imitation SWI components BAZ2A and BAZ2B limit efficient tissue regeneration by restricting increases in protein synthesis via suppression of rRNA transcription. We will test different aspects of this hypothesis by validating Baz2a and Baz2b genes as bona fide regeneration regulators (Aim 1), by understanding the global epigenetic activities of BAZ2 containing complexes (Aim 2), and by determining if increased protein synthesis is a key mechanism by which BAZ2 inhibition promotes regeneration (Aim 3). This project will define the regenerative phenotypes and molecular mechanisms associated with ISWI chromatin remodeling. Our studies will facilitate clinical drug development of small molecule inhibitors of BAZ2 proteins for use in enhancing tissue regeneration in the liver and intestine.

项目摘要 Planaria，Newts和斑马鱼的有效再生能力在哺乳动物中大为丢失，这是一种观察 这对人类健康有形。受损的组织再生可能导致疾病 例如肝肝硬化或炎症性肠病（IBD）。肝病环境中的再生有限 还排除了对癌症进行大型外科手术切除术的能力。相对缺乏再生 疗法可能部分是因为发现新目标很困难，并且取决于体内系统 无法在文化菜肴中复制。确定可以针对增强再生的新途径， 我们建立了一个体内CRISPR-CAS9筛选平台，以评估小鼠肝脏中的基因。使用此 高通量系统，我们评估了编码表观遗传机（例如组蛋白）的152个基因的影响 读者，作家和橡皮擦[2]。这确定了两个模仿SWI/SNF（ISWI）染色质重塑复合物 由BAZ2A和BAZ2B编码的亚基，这些基因以前尚不知道会调节再生的基因。这 BAZ2蛋白与SMARCA5酶之间的相互作用定义了核仁重塑络合物 （NORC），是使用ATP水解重塑核小体的ISWI复合物的五个亚型之一，特别是 在核糖体DNA（rDNA）基因座[3]。我们的验证研究表明，在体内cas9删除了baz2a或 BAZ2B在肝细胞再生模型中增加了肝脏再生。同样，化学抑制BAZ2A 使用特异性溴结构域抑制剂GSK2801的BAZ2B导致肝脏再生[4]。 此外，我们还发现，GSK2801可以促进结肠炎小鼠模型中的肠道恢复。这些 数据表明，含有ISWI/NORC染色质重塑的BAZ2对于器官很重要 多种疾病的再生和有前途的治疗靶标。我们的中心假设是模仿 SWI组件BAZ2A和BAZ2B通过限制蛋白质增加来限制有效的组织再生 通过抑制rRNA转录的合成。我们将通过验证该假设的不同方面 BAZ2A和BAZ2B基因作为真正的再生调节剂（AIM 1），通过了解全球表观遗传学 BAZ2包含复合物（AIM 2）的活性，并确定蛋白质合成是否增加是关键 BAZ2抑制促进再生的机制（AIM 3）。该项目将定义再生 与ISWI染色质重塑相关的表型和分子机制。我们的研究将有助于 BAZ2蛋白的小分子抑制剂的临床药物开发用于增强组织再生 在肝脏和肠道中。