Molecular mechanisms of mechanosensation in the cardiac pacemaker

心脏起搏器机械感觉的分子机制

• 批准号: 10670328
• 负责人: Claudia Marcela Moreno
• 金额: $ 38.88万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10670328
• 关键词: Acceleration; Acute; Affect; Animals; Area; Arrhythmia; Blood; Calcium; Calcium Oscillations; Cardiac; Cardiac pacemaker; Cells; Characteristics; Chemicals; Contracts; Coupling; Dependence; Development; Electrophysiology (science); Environment; Feedback; Fiber; Generations; Goals; Heart; Heart Atrium; Heart Rate; Image; In Situ Hybridization; In Vitro; Knockout Mice; Laboratories; Lung; Mechanics; Mediating; Modeling; Molecular; Mus; Organ; Pacemakers; Performance; Physiological; Physiological Processes; Piezo 1 ion channel; Piezo 2 ion channel; Piezo ion channels; Positioning Attribute; Preparation; Process; Proprioception; Protein Isoforms; Pump; Reflex action; Research; Right atrial structure; Role; Signal Pathway; Signal Transduction; Space Perception; Specificity; Stretching; Telemetry; Testing; Tissues; Toxin; Translations; Venous; cell type; experimental study; heart electrical activity; heart function; high resolution imaging; in vivo; innovation; insight; knock-down; mechanical force; mechanotransduction; mouse model; nodal myocyte; novel; overexpression; prevent; response; superresolution imaging; tool; ultrasound; voltage

Project Summary/Abstract In this project, we will test the overall hypothesis that PIEZO channels mediate mechanosensation in the cardiac pacemaker and that they are essential players on the heart rate acceleration evoked by mechanical stretch. We will leverage our expertise in the study of the cardiac pacemaker to enter into two new research fields for our laboratory: mechanosensation and mechano-electrical coupling. The heart is one of the most mechanically active organs in the body. Besides being a remarkably effective pump, the heart senses its mechanical environment and adjusts its performance to match the physiological demands. In a mechanism known as the “Bainbridge Reflex”, the cardiac pacemaker responds to the stretch induced by the increase in venous return with an acceleration of its pace to empty the heart effectively. To sense these constant changes in stretch, the pacemaker is equipped with stretch-activated channels, however, their molecular identity remains elusive. PIEZO channels mediate mechanotransduction in every cell type where its expression has been detected so far. Despite being expressed in the pacemaker and being considered the candidate to mediate pacemaker mechanotransduction, the role of PIEZO channels in this tissue has not been explored yet. This proposal will directly test the role of PIEZO channels in the stretch-activated response of the cardiac pacemaker. Our innovative approach includes the development of pacemaker-specific mouse lines to test the effect of PIEZO knockdown and overexpression in the pacemaker activity at the cellular, tissue, and animal level. We will combine immunodetection, in-situ hybridization, electrophysiology, high-resolution imaging, calcium imaging, and telemetry to: (Aim 1) Characterize the abundance, isoform relative expression, cell-expression specificity, and subcellular localization of Piezo1 and Piezo2 channels in the pacemaker tissue and isolated pacemaker cells. (Aim 2) Evaluate the role of PIEZO channels in the pacemaker stretch-activated current, the stretch- activated increase in intrinsic firing rate, the automaticity of pacemaker cells, and in their subthreshold calcium activity. (Aim 3). Determine the role of PIEZO channels in the stretch-activated electrical and calcium responses in the intact pacemaker tissue and their role in normal heart function in vivo. Completing the aims listed above will provide new insight into the molecular mechanisms of mechanotransduction in pacemaker cells and will help to identify novel targets for detecting and treating associated arrhythmias. Our results will also provide a diverse toolkit to identify multiple important mechanisms behind the translation of pacemaker stretch into heart rate acceleration, opening new avenues for our lab to study the downstream signaling pathways that are regulated by the mechanical activation of PIEZO channels in this tissue.

项目概要/摘要 在这个项目中，我们将测试 PIEZO 通道介导心脏机械感觉的总体假设 起搏器，它们是机械拉伸引起的心率加速的重要参与者。 将利用我们在心脏起搏器研究方面的专业知识，进入两个新的研究领域 实验室：机械感觉和机电耦合 心脏是机械活动最活跃的地方之一。 心脏除了是一个非常有效的泵之外，还能感知其机械环境。 并通过称为“Bainbridge”的机制调整其性能以满足生理需求。 “反射”，心脏起搏器对静脉回流增加引起的拉伸做出反应 加速其步伐以有效地清空心脏，以感受这些不断变化的伸展。 起搏器配备有拉伸激活通道，然而，它们的分子身份仍然难以捉摸。 PIEZO 通道在迄今为止已检测到其表达的每种细胞类型中介导机械转导。 尽管在起搏器中表达并被认为是调解起搏器的候选者 机械转导，PIEZO 通道在该组织中的作用尚未被探索。 直接测试 PIEZO 通道在心脏起搏器拉伸激活响应中的作用。 我们的创新方法包括开发起搏器特异性小鼠品系来测试 PIEZO 的效果 我们将在细胞、组织和动物水平上抑制和过度表达起搏器活性。 结合免疫检测、原位杂交、电生理学、高分辨率成像、钙成像、 和遥测：（目标 1）表征丰度、亚型相对表达、细胞表达特异性、 起搏器组织和离体起搏器中 Piezo1 和 Piezo2 通道的亚细胞定位 （目标 2）评估 PIEZO 通道在起搏器拉伸激活电流（拉伸激活电流）中的作用。 激活内在放电率、起搏细胞的自动性及其阈下钙的增加 确定 PIEZO 通道在拉伸激活的电和钙反应中的作用。 完整的起搏器组织及其在体内正常心脏功能中的作用。 将为起搏细胞中机械转导的分子机制提供新的见解，并将有助于 确定检测和治疗相关心律失常的新靶标，我们的结果也将提供多样化的结果。 用于识别起搏器伸展转化为心率背后的多种重要机制的工具包 加速，为我们实验室研究受监管的下游信号通路开辟新途径 通过该组织中压电通道的机械激活。