ИСТИНА

Sponges – the most ancient group of metazoans. They have unique features of organization which not found in other animals. Impressive plasticity of sponge body is one of such features. The most outstanding manifestation of this plasticity is sponge cell reaggregation. Different multicellular aggregates form during reaggregation ending in the reconstruction of intact sponge. So, it is a unique model system to study the cells potencies and behavior in sponges. We studied cell reaggregation in demosponge Halisarca dujardinii, which cells are able to reconstruct intact sponge organization during this process. Using histological, ultrastructural and immunohistochemical methods we described the fate and some aspects of the behavior of main cell types during different stages of cell reaggregation. At the beginning of reaggregation, the mass cell differentiation takes place – the most of the cells lose their characteristic features and become indistinguishable from maternal amoebocytes, forming the heterogeneous pool of amoebocytes. Only choanocytes and cells with inclusions can also be found in primary aggregates. Formation of primmorphs (aggregates with exopinacoderm) is accompanied by surface amoebocytes and choanocytes differentiation to the exopinacocytes. Finally, during the reconstruction of intact sponge organization new endopinacocytes, choanocytes and lophocytes differentiate both from the heterogeneous pool of amoebocytes and dedifferentiated choanocytes. Cells with inclusions do not change their initial differentiation during the whole process of reaggregation. The intensity of cell proliferation in intact sponge tissues and during reaggregation was studied using EdU staining. Financial support by Russian Foundation for Basic Research no 16-04-00084 and the Russian Science Foundation no 17-14-01089 is gratefully acknowledged. How to cite: Lavrov AI, Bolshakov FV and Kosevich IA. Behavior and fate of main cell types during Halisarca dujardinii cell reaggregation [version 1; not peer reviewed]. F1000Research 2017, 6:1523 (slides) (doi: 10.7490/f1000research.1114760.1)