Endosomal trafficking and functions in cardiomyocytes: insights from Arf6 signaling

我们研究计划的长期愿景是更好地了解基本的运输机制，该机制决定了一些蛋白质如何从心脏到达收缩细胞的表面，即心肌细胞。为了实现这一目标，我们首先建议通过对小鼠的遗传操作来研究移除一种名为Arf6的蛋白质是如何影响心脏功能的。Arf6是其他细胞中蛋白质运输的重要调节因子。将进一步分析受Arf6去除影响的细胞表面蛋白，以确定Arf6如何影响这些蛋白的定位和/或降解，以及它如何影响它们在心肌细胞膜上的功能。此外，我们还将研究Arf6在心肌源性外体的发生和释放中的作用，这些外体是心肌细胞在被其他细胞摄取之前在其直接环境和一般循环中释放的小囊泡。值得注意的是，我们将分别使用无偏蛋白质组分析和miRNA筛选来确定Arf6的缺失如何影响心肌细胞释放的外切体的数量，以及它们的蛋白质和miRNA含量。令人惊讶的是，尽管这种保守的细胞间通讯系统在过去的几年里引起了人们的兴趣，但这些外切体的产生机制还没有完全弄清楚。因此，我们预计我们的发现将加深我们对心脏内体和外体运输的了解，这是心肌细胞生物学中一个基本但仍然神秘的细胞过程。*这项研究计划的发现将为多个个人和群体带来好处。首先，在我的实验室形成的高素质人员(HQP)将受益于激励的研究环境。这些HQP将成为心脏生物学、分子信号、遗传操作和相关最先进技术的专家，如超声心动图对小鼠模型的评估，以解决心脏研究领域最紧迫的挑战。此外，考虑到人们对基础心血管研究日益增长的兴趣以及这一研究计划的新颖方面，我们相信我们的发现将产生可转置的知识，这些知识将推动其他研究小组在各自专业领域的假说和发现。**

The long-term vision of our research program is to better understand a fundamental trafficking mechanism that dictate how some proteins reach the surface of contractile cells from the heart, namely the cardiomyocytes. To achieve such goal, we first propose to study, by genetic manipulation of mice, how the removal of a protein named Arf6, an important regulator of protein trafficking in other cells, is impacting heart function. Cell-surface proteins affected by the removal of Arf6 will be further analysed to establish how Arf6 impacts the localization and/or degradation of these proteins and how it affects their function at the membrane of cardiomyocytes. Moreover, we will investigate the role of Arf6 in the genesis and release of cardiac-derived exosomes, which are small vesicles released by cardiomyocytes in their immediate environment and the general circulation before being uptake by other cells. Notably, we will determine how the absence of Arf6 affects the number of exosomes released by cardiomyocytes, but also their protein and miRNA content using unbiased proteomic assays and miRNA screens, respectively. Surprisingly, while this conserved communication system between cells has gained interest in the past years, the mechanisms involved in the production of these exosomes are not yet completely understood. Hence, we expect that our findings will deepen our knowledge about the cardiac endosomal and exosomal trafficking, a fundamental but still enigmatic cellular process in cardiomyocyte's biology.******The discoveries originating from this research program will provide benefits to multiple individuals and groups. First, the highly qualified personnel (HQP) formed in my laboratory will benefit from a stimulating research environment. These HQP will become expert in cardiac biology, molecular signaling, genetic manipulation, and related state of the art technology, like echocardiography assessment of murine model, to address the most pressing challenges in the cardiac research field. Also, considering the growing interest in fundamental cardiovascular research and the novel aspects of this research program, we believe our discoveries will generate transposable knowledge that will lead forward the hypothesis and discoveries of other research groups in their own field of expertise.**