Regulation of Cardiac Gene Expression by the L-type Calcium Channel, CaV1.2.

L 型钙通道 CaV1.2 调节心脏基因表达。

• 批准号: 7932284
• 负责人: Robert Nathan Correll
• 金额: $ 5.05万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-07 至 2012-01-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7932284
• 关键词: Adenoviruses; Adenylate Cyclase; Adrenergic Receptor; American; Animal Model; Animals; Arrhythmia; Binding; Biological Assay; Calcineurin; Cardiac; Cardiac Muscle Contraction; Cardiac Myocytes; Caveolae; Caveolins; Cleaved cell; Complex; Coupling; Development; Diagnosis; Disease; Distal; Event; Exhibits; Fellowship; Gap Junctions; Gases; Gene Chips; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Global Change; Goals; Heart; Heart Diseases; Heart Hypertrophy; Heart failure; Infection; Injury; L-Type Calcium Channels; Language; Mediating; Mediator of activation protein; Membrane; Modeling; Monomeric GTP-Binding Proteins; NFAT Pathway; Neurons; Nuclear; Pathway interactions; Physiology; Play; Population; Positioning Attribute; Protein Dephosphorylation; Protein phosphatase; Proteins; Publishing; Regulation; Reporter; Role; RyR2; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Sarcoplasmic Reticulum; Signal Transduction; Transcriptional Regulation; Transgenic Animals; Transgenic Mice; Work; combat; in vivo; inhibitor/antagonist; mouse model; overexpression; pressure; programs; research study; transcription factor; voltage

DESCRIPTION (provided by applicant): 5.3 million Americans are diagnosed with heart failure, which is accompanied by altered Ca2+ handling and transcriptional changes leading to pathological cardiac remodeling. One such pathway, Ca2-t-regulated calcineurin/NFAT, is an essential regulator for the development of cardiac hypertrophy. The cardiac Ca2+ channel CaVI .2, which is required for excitation-contraction coupling, can also be localized to caveolar signaling microdomains that allow local Ca2+ influx through these channels to participate in signaling events and transcriptional regulation, perhaps via calcineurin/NFAT. To examine the contribution of caveolar CaV1.2 to cardiac gene regulation, in aim 1 we propose to create an adenovirus and transgenic animal expressing a chimeric RGK protein fused to a caveolin-binding motif. RGK proteins are small GTPases that completely inhibit high voltage-gated Ca2+ channels (such as CaV1.2) by direct association with the channel complex when overexpressed. Localization of the chimeric RGK protein to caveolae should allow targeted inhibition of caveolar CaVI .2 only, allowing us to observe changes in activity in Ca2+-regulated transcription factors using reporter assays, and global changes in gene expression by gene chip assay. Further experimentation will determine whether inhibition of caveolar CaV1.2 is protective against heart failure in an animal pressure overload model. Recently it was demonstrated in neurons that the cleaved C- terminus of CaVI .2 can function as a Ca2+-regulated transcription factor, however transcriptional activity of this fragment, termed CCAT, is unstudied in the heart. We propose creation of adenoviruses and transgenic animal models expressing CCAT to determine its contribution to transcriptional regulation in the heart by means of gene chip assay and further examination of CCAT roles in disease by examining whether it is protective or maladaptive in a pressure overload model of heart failure. Experiments proposed here will substantially increase our understanding of how Ca2+ signals initiate transcriptional changes important during heart failure. Lay language: Ca2+ signals are important for changes in gene expression that underlie heart disease. To examine the role of the cardiac L-type Ca2+ channel in transcription, we will construct a mouse model inhibiting this channel in signaling microdomains and determine the contribution of this channel population to gene transcription and heart failure. We similarly examine the role of the transcription factor encoded by the CaVI.2 C-terminus in disease by overexpression in a mouse model of heart failure. This work will help reveal the role of the cardiac L-type Ca2+ channel in regulation of gene expression related to disease and may suggest new translational strategies to combat heart failure.

描述（由申请人提供）：530万美国人被诊断患有心力衰竭，这伴随着改变的Ca 2+处理和转录变化，导致病理性心脏重塑。其中一个这样的途径，Ca 2-t调节的钙调神经磷酸酶/NFAT，是心脏肥大发展的重要调节因子。兴奋-收缩偶联所需的心脏Ca 2+通道CaV1.2也可以定位于小窝信号传导微结构域，其允许局部Ca 2+流入通过这些通道参与信号传导事件和转录调节，可能通过钙调磷酸酶/NFAT。为了研究caveolar CaV1.2对心脏基因调控的贡献，在目标1中，我们提出创建表达融合到caveolin结合基序的嵌合RGK蛋白的腺病毒和转基因动物。RGK蛋白是小GTP酶，当过表达时，通过与通道复合物直接缔合而完全抑制高电压门控Ca 2+通道（如CaV1.2）。嵌合RGK蛋白定位于小窝应允许仅靶向抑制小窝CaV1.2，从而允许我们使用报告分析观察Ca 2+调节的转录因子的活性变化，以及通过基因芯片分析观察基因表达的全局变化。进一步的实验将确定在动物压力超负荷模型中抑制小窝CaV1.2是否对心力衰竭具有保护作用。最近在神经元中证明，CaV1.2的切割的C末端可以作为Ca 2+调节的转录因子起作用，然而，该片段（称为CCAT）的转录活性在心脏中未研究。我们建议建立腺病毒和转基因动物模型表达CCAT，以确定其在心脏中的转录调控的贡献，通过基因芯片测定和进一步检查CCAT在疾病中的作用，通过检查它是否是保护性的或适应不良的压力超负荷模型的心力衰竭。这里提出的实验将大大增加我们对Ca 2+信号如何启动心力衰竭过程中重要的转录变化的理解。外行语言：Ca 2+信号对心脏病基础基因表达的变化很重要。为了研究心脏L型Ca 2+通道在转录中的作用，我们将构建一个小鼠模型，在信号微区抑制该通道，并确定该通道群体对基因转录和心力衰竭的贡献。我们同样研究了CaVI.2 C-末端编码的转录因子在心力衰竭小鼠模型中过表达疾病中的作用。这项工作将有助于揭示心脏L型Ca 2+通道在调节疾病相关基因表达中的作用，并可能提出新的翻译策略来对抗心力衰竭。