Differentiation and function of intracardiac valve cells

果蝇心脏中的血淋巴流动由心内瓣膜控制。瓣膜将心脏后腔与前主动脉分开，在幼虫体内构成一个简单的门状结构。心内瓣膜只由两个单独的细胞组成，这两个细胞都具有独特的组织学特征，具有巨大的囊泡状间隔，我们称之为瓣膜小体。瓣膜小体是幼虫和成年果蝇心脏瓣膜的特征，在任何其他心肌细胞中都不形成。在这个项目中，我们有两个首要目标。一方面，我们想要分析在分子和细胞水平上，对瓣膜小体的形成至关重要的循环内小体是如何被招募到瓣膜小体的。Rab11是这里感兴趣的焦点，因为我们确定Rab11-RES在第一个应用期是瓣膜小体形成所必需的。我们的第二个目标是分析心脏瓣膜细胞对心脏泵浦功能的重要性。在这里，我们研究心脏瓣膜缺失或缺陷的突变体，并用生命标记物测量活动物的血淋巴流量。我们认为果蝇的心脏瓣膜细胞是一种进化上的新奇事物，在这种进化中，祖先的基本内体通路被修改，以满足特定的组织学和生理要求。循环蛋白质的典型途径(RE途径)在瓣膜细胞中被“劫持”，以产生一个新的和独特的细胞器--瓣膜小体。我们将从我们的研究中了解到，组织学上的以及最终的解剖学上的新颖性是如何在进化过程中通过利用现有“构建工具包”中的模块来产生的。

Haemolymph flow in the Drosophila heart is controlled by intracardiac valves. The valve separates the posterior heart chamber from the anterior aorta and constitutes a simple gate-like structure in the larvae. The intracardiac valve is formed by only two individual cells, both of which display a unique histology with giant vesicular-like compartments, which we called valvosomes. Valvosomes are a characteristic feature of larval and adult Drosophila cardiac valves and are not formed in any other cardiomyocyte. In this project, we have two overarching goals. On the one hand, we want to analyse how exactly, on the molecular and cellular level, recycling endosomes, which are essential for the formation of valvosomes, are recruited towards valvosomes. Rab11 is the focus of interest here, as we identified Rab11-REs as essential for valvosome formation in the first application period. Our second goal is to analyze the importance of the cardiac valve cells for the pumping function of the heart. Here we study mutants with missing or defective cardiac valves and measure haemolymph flow with life markers in living animals. We consider the cardiac valve cells in flies as an evolutionary novelty, in which ancestral, fundamental endosomal pathways were modified to meet specific histological and physiological requirements. The canonical pathway for recycling proteins (RE pathway) is being "hijacked" in valve cells to generate a new and unique organelle, the valvosome. We will learn from our studies how histological and, eventually, anatomical novelties are generated during evolution by utilizing modules from an existing "construction kit".