Changes in L-type calcium channels during aging in the heart's pacemaker

项目摘要 而不是被认为是生命的另一个阶段，衰老现在被认为是一个主要的风险因素， 心脏病这些年龄引发的疾病之一是心脏的天然起搏器功能障碍， 窦房结（SAN）。SAN功能障碍是超过20万个人工起搏器中50%的原因 在美国每年都要植入SAN起搏功能依赖于钙信号传导， 电压门控离子通道和内部钙储存。我科学生涯的长期目标是 了解衰老如何重塑心脏中的钙信号，以及这与心脏病发作的关系 疾病这个K99/R 00提案是起点，我将确定老化如何改变 电压门控L型钙通道的表达和分布。尽管L型钙通道 在SAN细胞中维持动作电位的通道，这些通道在 对衰老的研究很少。本提案分为两个阶段：培训K99阶段将侧重于 研究L型钙通道的耦合，其在起搏中的作用以及如何受衰老的影响。 这种通道耦合是我在海马神经元中发现的一种新的钙促进机制， 在SAN中还没有研究过。在培训阶段，我还将培养技术和学术技能 关于衰老和心脏生理学。独立的R 00阶段将专注于衰老如何改变表达， L型钙通道的分布和功能。对于这一部分，我将利用我以前的培训 和CaV1.3通道研究的专业知识。我会用电生理学来描述 青年和老年小鼠L型钙通道的特性。我将使用突变小鼠品系（CaV1.3-/-和 CaV1.2DHPins）来剖析L型钙电流的成分，并发现衰老是否调节它们 差异化。此外，我将使用扩展显微镜和超分辨率成像来生成 衰老过程中CaV1.2和CaV1.3通道在SAN中表达和分布的变化。此工具 为进一步研究衰老过程中SAN中蛋白质的重塑提供了依据。这些结果一起 将作为我第一个R 01的基础，并将启动我独立研究生涯的开始。 为了成功过渡到独立，我将依靠一个心脏病专家团队的指导， 和衰老生理学，包括费尔南多·桑塔纳博士、爱德华·拉卡塔博士、尼帕万·恰姆维蒙瓦特博士和 博士唐纳德·贝尔斯。他们将密切关注我的实验和学术训练，帮助我建立 我的职业发展战略。多样化的专业知识和高度互动的科学 加州大学戴维斯分校的环境特别适合促进和支持这一提议。K99/R 00奖项 是我在学术道路上前进的一个独特机会。这将帮助我巩固一个 创新利基对钙信号的衰老研究，并提供我所需的学术 和技术培训来开始我的独立调查员生涯

Project Summary Rather than being considered as another phase of the lifespan, aging is now considered a major risk factor for heart diseases. One of these age-triggered diseases is the dysfunction of the natural pacemaker of the heart, the sinoatrial node (SAN). SAN dysfunction is the cause of 50% of the over 200.000 artificial pacemakers implanted every year in the US. SAN pacemaking function depends on the calcium signaling sustained by voltage-gated ion channels and the internal calcium stores. The long-term of my scientific career is to understand how aging remodels calcium signaling in the heart and how this relates with the onset of heart diseases. This K99/R00 proposal is the starting point, where I will determine how aging changes the expression and distribution of voltage gated L-type calcium channels. Despite that L-type calcium channels are the channels that sustain the action potential in SAN cells, the changes that these channels undergo during aging are poorly explored. This proposal is divided in two phases: the training K99 phase will focus on the study of the coupling of L-type calcium channels, its role in the pacemaking and how it is affected by aging. This channel coupling is a new mechanism of calcium facilitation that I discovered in hippocampal neurons and that have not been studied in the SAN. During the training phase I will also build technical and academic skills on aging and cardiac physiology. The independent R00 phase will focus on how aging changes the expression, distribution and function of L-type calcium channels. For this part I will take advantage of my previous training and expertise on the study of CaV1.3 channels. I will use electrophysiology to characterize the biophysical properties of the L-type calcium channels in young and old mice. I will use mutant mice strains (CaV1.3-/- and CaV1.2DHPins) to dissect the components of the L-type calcium current and find if aging regulates them differentially. In addition, I will use expansion microscopy and super-resolution imaging to generate maps of the change in the expression and distribution of CaV1.2 and CaV1.3 channels in the SAN during aging. This tool will be useful for further studies in the remodeling of protein in the SAN during aging. Together these results will serve as the foundation of my first R01 and will launch the beginning of my independent research career. For a successful transition to the independence I will count with the mentoring of a team of experts in cardiac and aging physiology, including Dr. Fernando Santana, Dr. Edward Lakatta, Dr. Nipavan Chiamvimonvat and Dr. Donald Bers. They will follow very close my experimental and academic training and help me to establish my career development strategies. The diverse array of expertise and the highly interactive scientific environment at UC Davis is particularly well-suited to foster and support this proposal. The K99/R00 award constitutes a unique opportunity for my advance in the academic track. It will help me to consolidate an innovative niche on the study of the aging of calcium signaling and provide me with the necessary academic and technical training to launch my career as an independent investigator.