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Expanding the Pathogenic Mechanisms of Calmodulinopathies

扩展钙调蛋白病的致病机制

基本信息

批准号：
10580095
负责人：
Ivy E Dick
金额：
$ 19.31万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2024-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10580095
关键词：
Action Potentials Arrhythmia Binding Biological Models Biophysics Brain Calcium Calcium Channel Calmodulin Cardiac Cell physiology Cells Closure by clamp Coupling DNA Sequence Alteration Development Developmental Delay Disorders Disease Electrophysiology (science)Elements Exhibits Family Feedback Fluorescence Resonance Energy Transfer Future Genetic Transcription Heart Human Hybrids Image Immune system Impairment Incidence Induced pluripotent stem cell derived neurons Life Lobe Mediating Morphology Muscle Contraction Mutation Neurologic Neurologic Deficit Neurologic Dysfunctions Neurons Neuropathogenesis P-Q type voltage-dependent calcium channel Pathogenesis Pathogenicity Pathology Patients Phenotype Play Process Proteins Regulation Research Role Signal Transduction Source Symptoms Tail Toxin biophysical analysis comorbidity electrical property experimental study gain of function heart function heart rhythm induced pluripotent stem cell interest loss of function mutant neuronal excitability neuropathology neuropsychiatry neurotransmission patch clamp sensor stem cell model voltage voltage clamp

项目摘要

Calmodulin (CaM) is a ubiquitous calcium sensor, vital to immune system, heart and brain function. Mutations within CaM result in a set of disorders known as calmodulinopathies. Patients harboring these CaM mutations suffer from life-threatening cardiac arrhythmias, which are often accompanied by neurodevelopmental delay or other neurological dysfunction. While CaM has numerous potential targets which may be altered in calmodulinopathies, voltage gated calcium channels (VGCCs) stand out as likely pathogenic elements. For CaV1-2 channels, CaM is known to preassociate with the carboxy-tail of the channel. Upon binding Ca2+, this resident CaM initiates either of two important forms of feedback regulation; Ca2+/CaM dependent inactivation (CDI) or Ca2+/CaM dependent facilitation (CDF). Each of these forms of channel regulation can be independently driven by a single lobe of CaM, with CaV1.2, CaV1.3 and CaV2.1 each strongly modulated by Ca2+ binding to the C-lobe of CaM. As the majority of calmodulinopathy mutations have thus-far impacted the CaM C-lobe, this lobe-specific regulation implies a large impact of calmodulinopathy mutations on the regulation of these three channels. In fact, we have previously demonstrated that calmodulinopathy mutations are capable of disrupting the CDI of CaV1.2 channels, resulting in the long-QT phenotype seen in patients6,7. However, the effect of CaM mutations on VGCCs other than CaV1.2 has yet to be elucidated, nor have the mechanisms underlying the neurological phenotypes of calmodulinopathy patients been explored. As CaV1-2 channels play critical roles in neuronal excitability, excitation-transcription coupling, and neurotransmission, we propose that they are likely contributors to the neuropathogenesis of calmodulinopathies. We will therefore undertake a biophysical study of the impact of calmodulinopathy mutations across the CaV1-2 channel family and evaluate the impact of these mutations on neuronal function. In particular, we hypothesize that CaM mutations which alter the Ca2+ binding to the C-lobe of the protein will decrease CDI in CaV1.2 and CaV1.3, and disrupt CDF in CaV2.1. To evaluate the functional impact of these mutations, we will generate induced pluripotent stem cell derived neurons (iPSC-neurons) from calmodulinopathy patients, and elucidate a cellular phenotype correlating with the neurological deficits of calmodulinopathy patients. Thus, we will undertake one of the first studies aimed at understanding the impact of calmodulinopathy mutations outside the heart, expanding our understanding of the pathogenic mechanisms underlying this disorder.

钙调素（CaM）是一种普遍存在的钙传感器，对免疫系统、心脏和大脑功能至关重要。突变导致一系列称为钙调蛋白病的疾病。携带这些CaM突变的患者患有危及生命的心律失常，通常伴有神经发育迟缓，或其他神经功能障碍。虽然钙调素有许多潜在的目标，可以改变，在钙调蛋白病中，电压门控钙通道（VGCC）作为可能的致病因素而突出。为 CaV 1 -2通道，已知CaM与通道的羧基尾预缔合。当结合Ca 2+时，常驻CaM启动两种重要形式的反馈调节之一; Ca 2 +/CaM依赖性失活 (CDI)或Ca 2 +/CaM依赖性易化（CDF）。每种形式的通道调节都可以独立地由CaM的单个叶驱动，CaV1.2，CaV1.3和CaV2.1各自通过Ca 2+结合到CaV2.1上来强烈调节。钙调素C叶。由于大多数钙调蛋白病突变已经影响了CaM C叶，因此，叶特异性调节意味着钙调蛋白病突变对这三种蛋白的调节有很大影响。渠道事实上，我们以前已经证明钙调蛋白病突变能够破坏 CaV1.2通道的CDI，导致在患者中观察到的长QT表型6，7。然而，CaM的作用除了CaV1.2之外，VGCC上的突变尚未阐明，也没有潜在的机制。钙调蛋白病患者的神经系统表型进行了探索。由于CaV 1 -2通道在细胞内的表达和分布中起着关键作用，神经元兴奋性，兴奋-转录偶联和神经传递，我们认为它们可能是钙调蛋白病的神经发病机制的贡献者。因此，我们将进行一项生物物理研究，钙调蛋白病突变对CaV 1 -2通道家族的影响，并评估这些突变的影响。神经元功能的突变特别是，我们假设改变Ca 2+结合的CaM突变，在CaV1.2和CaV1.3中，与蛋白质的C端半叶连接将降低CDI，并破坏CaV2.1中的CDF。评价这些突变的功能影响，我们将从钙调蛋白病患者中产生诱导多能干细胞衍生的神经元（iPSC-神经元），并阐明与神经系统疾病相关的细胞表型。钙调素缺乏症患者。因此，我们将进行第一批旨在了解心脏外钙调蛋白病突变的影响，扩大了我们对致病性这种疾病的潜在机制。