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

项目摘要 衰老不再被认为是寿命的另一个阶段，而是现在被认为是 心脏病。这些由年龄引发的疾病之一是心脏自然起搏器功能障碍， 窦房结(SAN)。在200.000多个人工起搏器中，有50%是由窦房结功能障碍引起的 每年都会在美国植入。窦房结起搏功能依赖于 电压门控离子通道和内部钙存储。我科学生涯的长期目标是 了解衰老如何改变心脏中的钙信号，以及这与心脏发病的关系 疾病。这份K99/R00提案是一个起点，我将在这里确定老化如何改变 电压门控型L钙通道的表达和分布。尽管L型钙离子通道 维持窦房结细胞动作电位的通道，这些通道在 人们对衰老的研究很少。这项建议分为两个阶段：培训K99阶段将侧重于 L钙通道偶联及其在起搏中的作用及衰老影响的研究。 这种通道偶联是我在海马神经元中发现的一种新的钙促进机制， 还没有在桑人那里研究过。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R00阶段将关注衰老如何改变表达， L型钙通道的分布和功能。对于这一部分，我将利用我之前的培训 和研究CaV1.3通道的专业知识。我将使用电生理学来描述生物物理 L型钙通道在幼龄和老年小鼠体内的特性。我将使用突变小鼠品系(CaV1.3-/-和 CaV1.2DHPins)，解剖L型钙电流的成分，并发现它们是否受衰老的调节 差异化的。此外，我将使用扩展显微镜和超分辨率成像来生成 CaV1.2和CaV1.3通道在衰老过程中在窦房结的表达和分布的变化。此工具 将有助于进一步研究老化过程中窦房结内蛋白质的重塑。将这些结果放在一起 将作为我的第一个R01的基础，并将启动我独立研究生涯的开始。 为了成功地过渡到独立，我将依靠一支心脏专家团队的指导 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·奇安维蒙特博士和 唐纳德·贝斯医生。他们将密切关注我的实验和学术训练，并帮助我建立 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培养和支持这一提议。K99/R00奖 这对我的学术发展来说是一个难得的机会。它将帮助我巩固一个 在钙信号的老化研究上的创新为我提供了必要的学术支持 和技术培训来开启我作为独立调查员的职业生涯。

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.