Proteome profiling of three cell populations from the common starfish Asterias rubens

The origin of cells involved in regeneration in Echinoderms is an open question till now. Most experimental data support the process of transdifferentiation as the main mechanism, although the activity of progenitor/stem cells is also considered. The renewal of coelomocytes, the cells which occupy the coelomic cavity in Asterias rubens is an example of physiological regeneration. Although it is considered that coelomic epithelium is the main source of coelomocytes, many details of this process remain unclear. In this study, we provide evidence of the origin of several types of coelomocytes in A. rubens from the coelomic epithelium, with particular emphasis on small undifferentiated cells. The concept of a pool of marginal coelomocytes is introduced as cells sequestered on the surface of the coelomic epithelium and characterized by a special cellular composition. Proteomic analysis by LC-MALDI TOF/TOF MS identified in total 403 proteins in coelomocytes (COE), coelomic epithelium (CE) and coelomic epithelium subpopulation enriched with undifferentiated cells (CEW). Proteins common and associated with each cell pool were revealed and the intermediate status of cells on the border of coelomic epithelium and coelom was confirmed. The potential players involved in regenerative processes were identified.