CaMKII-dependent mechanisms in RBM20 cardiomyopathy

RBM20 心肌病中的 CaMKII 依赖性机制

• 批准号: 422319743
• 负责人: Professor Dr. Johannes Backs
• 金额: --
• 依托单位: Institut für Experimentelle Kardiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/422319743?language=en
• 关键词: CaMKII; dependent; mechanisms; RBM20; cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the major causes of heart failure. 30-50% of all DCM cases are familial, and in 3-7% of familial DCM cases a mutation in RNA-binding motif protein 20 (RBM20) seems to be the cause. RBM20 mutations often lead to a clinically aggressive form of DCM, and are associated with progressive cardiac dysfunction, disturbed cardiac Ca2+ handling, and an increased risk of malignant ventricular arrhythmias. We have previously identified misspliced CaMKIIδ as a candidate target that may contribute to the disturbed calcium handling and increased arrhythmic burden of RBM20 mutation carriers, but it is yet unknown to what extent and how misspliced CaMKIIδ contributes to this phenotype. This projects overall aim is to further unravel the molecular mechanisms that cause arrhythmias and cardiac dysfunction in RBM20 mutation carriers. In WP1, we will cross Rbm20-/- mice to CaMKIIδ-/- mice to provide proof of concept that CaMKIIδ indeed serves as a critical splicing target of RBM20. In parallel, in order to investigate why specifically the splice variant CaMKIIδA causes disturbed calcium handling and arrhythmias, we will perform unbiased IP-mass spectrometry and phospho-proteomics to identify the specific target profiles of the different cardiac CaMKIIδ splice isoforms (WP2). Third, as a translational approach, we will test the potential therapeutic strategy of lowering intracellular Ca2+ with the use of verapamil and the recently disclosed new CaMKII inhibitor GS-680 from Gilead to reduce the arrhythmia burden Rbm20-/- mice (WP3). Furthermore, we will investigate transcriptional and metabolic dysregulation in Rbm20-/- mice (WP4). Lastly, we will interrogate the contribution of CaMKII-mediated HDAC4 transcriptional regulation and how this impacts on arrhythmias and cardiac dysfunction in Rbm20-/- mice (WP5).

扩张型心肌病（DCM）是心力衰竭的主要原因之一。30-50%的DCM病例是家族性的，在3-7%的家族性DCM病例中，RNA结合基序蛋白20（RBM 20）的突变似乎是原因。RBM 20突变通常导致临床上侵袭性形式的DCM，并且与进行性心功能障碍、心脏Ca 2+处理紊乱和恶性室性心律失常风险增加相关。我们先前已经鉴定了错误剪接的CaMKIIδ作为候选靶标，其可能导致RBM 20突变携带者的钙处理紊乱和血液负担增加，但尚不清楚错误剪接的CaMKIIδ在多大程度上以及如何导致这种表型。该项目的总体目标是进一步揭示导致RBM 20突变携带者心律失常和心功能障碍的分子机制。在WP 1中，我们将Rbm 20-/-小鼠与CaMKIIδ-/-小鼠杂交，以提供CaMKIIδ确实作为RBM 20的关键剪接靶标的概念证明。同时，为了研究为什么剪接变体CaMKIIδA会引起钙处理紊乱和心律失常，我们将进行无偏IP质谱和磷酸化蛋白质组学，以确定不同心脏CaMKIIδ剪接异构体（WP 2）的特定靶谱。第三，作为一种转化方法，我们将测试使用维拉帕米和最近公开的来自吉利德的新CaMKII抑制剂GS-680降低细胞内Ca 2+的潜在治疗策略，以减少Rbm 20-/-小鼠的心律失常负担（WP 3）。此外，我们将研究Rbm 20-/-小鼠（WP 4）的转录和代谢失调。最后，我们将询问CaMKII介导的HDAC 4转录调控的贡献，以及这如何影响Rbm 20-/-小鼠的心律失常和心功能障碍（WP 5）。