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.

项目摘要/摘要 在这个项目中，我们将测试压电通道介导心脏机制的总体假设 起搏器，他们是通过机械伸展引起的心率加速的重要参与者。我们 将利用我们在心脏起搏器研究中的专业知识来进入两个新的研究领域 实验室：机械力和机械电气耦合。心脏是最活跃的心脏之一 体内器官。此外，这是一个非常有效的泵，心脏会感觉到其机械环境 并调整其性能以符合身体需求。用称为“贝恩布里奇的机制” 反射”，心脏起搏器对静脉回流的增加而响应 加速其空间以有效清空心脏。为了感觉到这些不断的变化， 起搏器配备了拉伸激活的通道，但是它们的分子身份仍然难以捉摸。 压电通道介导了到目前为止检测到其表达的每种细胞类型的机械转移。 尽管在起搏器中表达并被认为是调解起搏器的候选人 机械转导，尚未探索压电通道在该组织中的作用。该提议将 直接测试压电通道在心脏起搏器的拉伸激活反应中的作用。 我们的创新方法包括开发起搏器特定的小鼠线以测试压电的效果 在细胞，组织和动物水平上的起搏器活性中的敲低和过表达。我们将 结合免疫检测，原位杂交，电生理学，高分辨率成像，钙成像， 和遥测至：（ AIM 1）表征抽象，同工型相对表达，细胞表达特异性， Pootemaker组织中的压电1和压电2通道的亚细胞定位和分离的起搏器 细胞。 （AIM 2）评估压电通道在起搏器拉伸激活电流中的作用，拉伸 - 激活的内在点火速率，起搏器细胞的自动化及其亚阈值钙 活动。 （目标3）。确定压电通道在拉伸激活的电和钙反应中的作用 在完整的起搏器组织中及其在体内正常心脏功能中的作用。完成上面列出的目标 将提供有关起搏器细胞中机制的分子机制的新见解，并将有助于 确定用于检测和治疗相关心律不齐的新目标。我们的结果还将为潜水员提供 工具包确定起搏器翻译背后的多种重要机制伸展为心率 加速度，为我们的实验室开辟了新的途径，以研究受调节的下游信号通路 通过该组织中压电通道的机械激活。