Histone Deacetylases in the Process of Halisarca dujardini Cell Reaggregation

One of the most common epigenetic modifications of proteins in eukaryotes is the acetylation/deacetylation of lysine. Histone deacetylases (HDACs) reduce the level of histone acetylation, which leads to the suppression of transcription. The participation of histone deacetylases in the regulation of cell proliferation and differentiation, embryonic development, and the occurrence and progression of malignant tumors is well documented for vertebrates. Mechanisms of gene expression regulation associated with the activity of histone diacetylases have not been studied in basal forms of multicellular animals. However, it is known that the process of reaggregations of sponge cells is accompanied by their dedifferentiation and transdifferentiation; it can indicate the involvement of diacetylases in the regulation of this process. The aim of the work was to study the expression of histone deacetylases in the sponge Halisarca dujardini (Demospongiae). Based on the analysis of the transcriptomes of the H. dujardini sponge and the genome of the Amphimedon queenslandica (Demospongia) sponge, representatives of all classes of Zn2+-dependent HDACs in sponges were identified. The differential expression of HDAC was analyzed in a suspension of H. dujardini sponge cells after dissociation of its body and in aggregates after 24 h of reaggregation. The dose-dependent effect of two selective HDAC class I inhibitors (sodium butyrate and valproic acid) on the process of cell reaggregation was studied. It is shown that the addition of selective HDAC class I inhibitors to the incubation medium during aggregation leads to a change in the morphological characteristics of cell aggregates. It can be assumed that the participation of histone deacetylases in the regulation of cell transdifferentiation is an evolutionarily ancient mechanism used by multicellular animals even before the formation of tissue organization.