Newswise — Genes sfrp and smoothened are crucially important for regeneration of lost organs. Scientists from Zhirmunsky National Scientific Center of Marine Biology, FEB RAS have found out that regeneration of sea cucumbers depends on genes sfrp (sfrp1/2/5, sfrp3/4) and gene smo. Humans also have these genes, so in future the obtained information can help to develop regenerative medicine. The research is published in Wound repair and regeneration journal.

Sea cucumbers, or holothyria, have porrect, often wormlike body, with various pappilae. These animals can regenerate small mucroes of body, such as tentacles, ambulacrum, cirri and prickes, heal dermal wounds. In unfavorable conditions these animals throw a part of their internal organs (that cells of nerve, muscle, digestive and ambulacral systems) and then quickly regenerate them. The process of regeneration is rather difficult and is coordinated by a lot of genes.

In frames of their new work scientists from Zhirmunsky National Scientific Center of Marine Biology, FEB RAS have found that holothurian Eupentacta fraudatrix – a common representative of fauna of the Japanese Sea – has two genes secreted Frizzled-relatedproteins (sfrp): sfrp1/2/5, sfrp3/4 and one gene smoothened (smo). Receptor Smoothened and secretable proteins sFRP serve as main participants of signal paths Hedgehog and Wnt, that control a lot of various processes: tumorigenesis, cell migration and embryonic development.

In order to find out functions of these genes in regeneration processes, scientists reduced their expression (synthesis of protein) with the help of small molecules of RNA. The work of genes was interrupted and that enabled scientists to understand which functions they answer for.  “It is known that expression of these genes is crucially vital for formation of regenerate of aquapharyngeal complex (AC) – the analogue of Aristotle’s lantern of sea hedgehog. Animals that were submitted to knockdown of studied genes, on the seventh day of regeneration didn’t form full-sized anlage of AC, that corresponds to this period of regeneration in the group of control animals. The reduction of expression of these genes either restrains formation pf AC (sfrp1/2/5) as a result of condensation of conjunctive tissue in the regenerate, that may occur due to inactivation of metalloproteinases (MMPs) – proteins, that rebuild fibers of conjunctive tissue, or almost completely destructs conjunctive tissue of a regenerate, leaving bare nerves and muscles (sfrp3/4), also destroying symmetry of formation of anlage of AC. Or even completely destroy formation of anlage of AC (smoothened)», - comments scientific associate of Laboratory of comparative cytology of National Scientific Center of Marine Biology, FEB RAS, Alexander Girich.

Mammals, including humans, also have these genes. Sfrp helps mammals to coordinate embryogenesis, formation of epithelial tissues, differentiation of cardiomyocytes and is involved in carcinogenesis. Smoothened is able to influence the processes of cell division, reconstruction of cytoskeleton, connected with cellular migration and lipid exchange. That is why results of the research don’t only help to understand biological processes of sea cucumbers, but make a base for development of technologies of regenerative medicine, that in the future probably enables to set into action similar processes of regeneration in humans.

Journal Link: Wound repair and regeneration