Forcing the sinoatrial node pacemaker function

项目总结 协调心率的起搏窦房结(SAN)会随着年龄的增长而功能障碍。 人诱导多能干细胞(HiPSC)来源的起搏心肌细胞构成的生物起搏剂 (P-CMS)可作为恢复窦性心律的一种治疗策略。 功能障碍。生物激发剂的发展受到诸如P-1分化率低等问题的阻碍。 来自HiPSCs的CMS和工程化起搏组织中起搏功能的长期维持。 P-CMS的功能和表型可以受到细胞外基质施加的机械力的影响 (ECM)形成细胞微环境和心脏收缩引起的周期性应变。ECM已经 在塑造工作CMS的表型方面得到了很好的证明。因此，最优的ECM还应该 促进和维持P-CMS的起搏功能。我们有数据表明，SAN的ECM可以 与HIPSC来源的CMS相比，即使在周期性应变下也更好地维持起搏表型 但诱发和维持起搏表型的确切机制 都不清楚。本项目的目标是了解P-CMS的机械转导机制 可以通过ECM进行调制。我们推测，窦房结细胞外基质可能调节机械信号转导。 驻留的P-CMS通过管腔的细胞-细胞外基质连接和筋膜的细胞-细胞连接附着于 保持起搏表型。为了测试我们假设的机械基础，我们提出了 以下三个目标：1)确定P-CMS中细胞外基质介导的机械转导信号；2)确定P-CMS中细胞外基质介导的机械转导信号 确定P-CMS中细胞-细胞介导的机械转导信号；3)确定整合的 细胞-细胞外基质和细胞-细胞连接网络在P-CMS的机械转导信号中的作用。更好地理解 在P-CMS的机械转导机制中，P-CMS可以从HIPSCs中产生人的P-CMS的来源。 术语起搏功能，一套工程可持续发展所必需的微环境标准 并启发未来针对SAN功能障碍的新的治疗或预防策略。

PROJECT SUMMARY Pacemaking sinoatrial node (SAN) that orchestrates the heart rhythm can become dysfunctional with aging. Biopacemakers composed of human induced pluripotent stem cell (hiPSC)-derived pacemaking cardiomyocytes (P-CMs) can be one therapeutic strategy that can restore the sinus rhythm in patients suffering from SAN dysfunction. The development of biopacemakers is hampered by issues such as low differentiation yield of P- CMs from hiPSCs and the long-term maintenance of the pacemaking function in engineered pacemaking tissues. The function and phenotype of P-CMs can be affected by mechanical forces imposed by the extracellular matrix (ECM) forming the cellular microenvironment and the cyclic strain due to cardiac contractions. The ECM has been well demonstrated for shaping the phenotype of the working CMs. Hence, an optimal ECM should also promote and sustain pacemaking function in P-CMs. We have data demonstrating that ECM of the SAN can better sustain the pacemaking phenotype in hiPSC-derived CMs even when subjected to cyclic strain compared to the left ventricular counterpart but the exact mechanisms that induce and maintain the pacemaking phenotype are unclear. The goal of this project is to understand the mechanisms of mechanotransduction in P-CMs that can be modulated by the ECM. We hypothesize that the SAN ECM may modulate the mechanotransduction in resident P-CMs via cell-ECM junctions at the costameres and the cell-cell junctions at the fascia adherens to maintain the pacemaking phenotype. To test the mechanistic underpinnings of our hypothesis, we propose the following three aims: 1) to determine the cell-ECM-mediated mechanotransduction signaling in P-CMs, 2) to determine the cell-cell-mediated mechanotransduction signaling in the P-CMs, and 3) to determine the integrated cell-ECM and cell-cell junction network in mechanotransduction signaling in the P-CMs. A better understanding of the mechanotransduction mechanisms in P-CMs can yield a source of human P-CMs from hiPSCs with long- term pacemaking function, a set of microenvironmental criteria necessary for engineering sustainable biopacemakers and inspire future new therapeutic or preventive strategies for SAN dysfunction.