Role of the giant protein titin in cardiac health and disease

巨型蛋白肌联在心脏健康和疾病中的作用

• 批准号: 10375457
• 负责人: Henk L. GRANZIER
• 金额: $ 88.44万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10375457
• 关键词: Address; Animal Model; Biology; Cardiac Myosins; Cardiac health; Clinical; Dilated Cardiomyopathy; Drug Screening; EFRAC; Elements; Excision; Exons; Failure; Functional disorder; Genes; Genetic Transcription; Goals; Heart; Heart Diseases; Heart failure; Location; Microfilaments; Molecular; Mutate; Mutation; Patients; Phosphorylation; Post-Translational Protein Processing; Protein Isoforms; Proteins; RNA Splicing; Research; Resolution; Role; Sarcomeres; Scientist; Stress; Striated Muscles; Talents; Techniques; Testing; Thick Filament; Time; Work; base; cardiac tissue engineering; connectin; disease-causing mutation; drug candidate; experience; heart function; innovation; myosin-binding protein C; novel; preservation; therapeutic target

Summary This proposal focuses on titin, the largest protein known, in heart function and disease. Titin forms a novel and multifunctional myofilament in the striated-muscle sarcomere with important roles that include regulating the diastolic stiffness of the heart. Recent breakthrough studies revealed that titin is of high clinical importance in both heart failure with preserved ejection fraction (HFpEF), and heart failure with reduced ejection fraction (HFrEF). Although significant progress has been made in understanding the basic biology of titin, major gaps in our understanding still remain, including a mechanistic understanding of how titin causes/contributes to heart disease. An important focus of this proposal will be on titin’s role in diastolic dysfunction, motivated by recent studies on patients with HFpEF that revealed deranged phosphorylation of titin’s molecular spring elements and diastolic stiffening. The full spectrum of posttranslational modifications that occur in HFpEF will be studied and high-resolution time-resolved spectroscopic techniques will focus on uncovering the structural changes in titin’s spring elements triggered by posttranslational modification. Drug screens will focus on identifying compounds that mimic or block these structural changes and functional studies will test whether newly discovered and candidate drugs ameliorate titin-based diastolic stiffening in HFpEF. Post-transcriptional mechanisms will be investigated as well, taking advantage of our recent work that has shown that splicing of titin can be manipulated to upregulate complaint titin isoforms and restore diastolic function. The functional efficacy of identified compounds will be tested on engineered heart tissues as well as on animal models. The second major focus of this proposal will be on titin in HFrEF. Several recent sequencing studies in large groups of patients revealed that mutations in the titin gene (TTN) are causative in ~20% of studied dilated cardiomyopathy (DCM) patients. Many of the mutations are truncation mutations (TTNtv) and they have a preferential location in the A-band segment of titin. The A-band segment is the least well-studied part of titin and an important goal of our research is to critically examine the biology of titin in this region of the sarcomere where disease-causing mutations are prominent. These studies include a focus on the role of titin in interacting with cMyBP-C (cardiac myosin-binding protein C, a clinically important thick filament protein). Animal models will be investigated in which TTNtv have been introduced in different regions of titin’s A-band segment. The effects of the mutations will be studied under baseline conditions, when stressed, and when occurring in combination with mutations in other genes. Importantly, we will also test whether excision of the mutated titin exons ameliorates titin-based DCM. In summary, capitalizing on my >20-year track record of innovative titin research, and utilizing our team of experienced scientists and talented trainees, this proposal sets ambitious goals that are expected to further accelerate understanding of the biology of titin, its role in heart disease and titin’s potential to function as a therapeutic target.

概括 该提案重点介绍了心脏功能和疾病中最大的蛋白质蛋白质。泰丁形成小说， 在绿色肌肉肉皮中的多功能肌丝具有重要的作用，包括调节 心脏的舒张僵硬。最近的突破性研究表明，泰丁在临床上具有很高的重要性 心力衰竭均具有保留的射血分数（HFPEF），以及减少射血分数的心力衰竭 （HFREF）。 我们的理解仍然存在，包括对Titin原因/如何促成内心的机械理解 疾病。该提案的一个重要重点将是蒂丁在舒张功能障碍中的作用 关于HFPEF患者的研究表明，Titin的分子春季元素和 舒张期僵硬。 HFPEF中发生的全部翻译后修饰将进行研究，并且 高分辨率的时间分辨光谱技术将着重于揭示Titin的结构变化 春季元素是由翻译后修改触发的。药物屏幕将集中于识别化合物 模仿或阻止这些结构性变化和功能研究将测试新发现和 候选药物在HFPEF中改善基于滴虫的舒张期。转录后机制将是 还调查了，利用我们最近的工作表明可以操纵滴定的剪接 为了上调投诉titin同工型并恢复舒张功能。确定的功能效率 化合物将在工程心脏组织以及动物模型上进行测试。第二个主要重点 该建议将在HFREF中进行。大量患者的一些最近的测序研究显示 在大约20％的研究型心肌病（DCM）患者中，Titin基因（TTN）中的突变是严重的。 许多突变是截断突变（TTNTV），它们在A波段中具有首选位置 山雀的细分市场。 A波段细分市场是Titin中最不足的部分，也是我们研究的重要目标 是在肉科中批判性地检查titin的生物学 著名的。这些研究包括关注Titin与CMYBP-C（心脏肌球蛋白结合）相互作用的作用 蛋白C，一种临床上重要的厚细丝蛋白）。将研究动物模型，其中TTNTV具有 是在Titin A波段领域的不同区域引入的。突变的影响将在 基线条件（应力时）以及与其他基因中的突变结合发生时。 重要的是，我们还将测试突变的Titin外显子是否可以改善基于滴虫的DCM。在 摘要，利用我的20年创新titin研究记录，并使用我们的团队 经验丰富的科学家和才华横溢的学员，该提案设定了雄心勃勃的目标，有望进一步 加速对钛生物学的理解，其在心脏病中的作用以及Titin的作用潜力 治疗靶标。