Meyer Christian, Paululat Achim
Department of Biology/Chemistry, Zoology & Developmental Biology, Osnabrück University, Osnabrück, Germany.
Center of Cellular Nanoanalytics (CellNanOs), Osnabrück University, Osnabrück, Germany.
PLoS Genet. 2025 Mar 20;21(3):e1011613. doi: 10.1371/journal.pgen.1011613. eCollection 2025 Mar.
Blood flow in metazoans is regulated by the activity of the heart. The open circulatory system of insects consists of relatively few structural elements that determine cardiac performance via their coordinated interplay. One of these elements is the intracardiac valve between the aorta and the ventricle. In Drosophila, it is built by only two cells, whose unique histology represents an evolutionary novelty. While the development and differentiation of these highly specialised cells have been elucidated previously, their physiological impact on heart performance is still unsolved. The present study investigated the physiological consequences of cardiac valve malformation in Drosophila. We show that cardiac performance is reduced if valves are malformed or damaged. Less blood is transported through the heart proper, resulting in a decreased overall transport capacity. A reduced luminal opening was identified as a main reason for the decreased heart performance in the absence of functional valves. Intracardiac hemolymph flow was visualised at the valve region by microparticle injection and revealed characteristic similarities to valve blood flow in vertebrates. Based on our data, we propose a model on how the Drosophila intracardiac valves support proper hemolymph flow and distribution, thereby optimising general heart performance.
后生动物的血流由心脏活动调节。昆虫的开放式循环系统由相对较少的结构元件组成，这些元件通过它们的协同相互作用来决定心脏功能。其中一个元件是主动脉和心室之间的心内瓣膜。在果蝇中，它仅由两个细胞构成，其独特的组织学特征代表了一种进化上的新奇之处。虽然这些高度特化细胞的发育和分化先前已得到阐明，但其对心脏功能的生理影响仍未解决。本研究调查了果蝇心瓣膜畸形的生理后果。我们发现，如果瓣膜畸形或受损，心脏功能会降低。通过心脏本身运输的血液减少，导致整体运输能力下降。在没有功能性瓣膜的情况下，管腔开口减小被确定为心脏功能下降的主要原因。通过微粒注射在瓣膜区域观察到心内血淋巴流动，并揭示了与脊椎动物瓣膜血流的特征相似性。基于我们的数据，我们提出了一个关于果蝇心内瓣膜如何支持适当的血淋巴流动和分布从而优化整体心脏功能的模型。
