Expression of Piwi, MMP, TIMP, and Sox during Gut Regeneration in Holothurian Eupentacta fraudatrix (Holothuroidea, Dendrochirotida)

Abstract

Mesodermal cells of holothurian Eupentacta fraudatrix can transdifferentiate into enterocytes during the regeneration of the digestive system. In this study, we investigated the expression of several genes involved in gut regeneration in E. fraudatrix. Moreover, the localization of progenitor cells of coelomocytes, juvenile cells, and their participation in the formation of the luminal epithelium of the digestive tube were studied. It was shown that Piwi-positive cells were not involved in the formation of the luminal epithelium of the digestive tube. Ef-72 kDa type IV collagenase and Ef-MMP16 had an individual expression profile and possibly different functions. The Ef-tensilin3 gene exhibited the highest expression and indicates its potential role in regeneration. Ef-Sox9/10 and Ef-Sox17 in E. fraudatrix may participate in the mechanism of transdifferentiation of coelomic epithelial cells. Their transcripts mark the cells that plunge into the connective tissue of the gut anlage and give rise to enterocytes. Ef-Sox9/10 probably controls the switching of mesodermal cells to the enterocyte phenotype, while Ef-Sox17 may be involved in the regulation of the initial stages of transdifferentiation.

Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases in Echinoderms: Structure and Possible Functions

“…Four hemopexin-like repeats are located after the catalytic domain. The second, 47 kDa (GHCL01010993.1), is Ef-MMP16 [ 79 ]. This is a furin-activatable MMP.…”

“…Its propeptide domain does not contain PGBD, and four hemopexin-like repeats are located at the C-terminus. It was shown that Ef-MMP16 expresses during gut regeneration in holothurian E. fraudatrix [ 79 ]. Its transcripts were found in the coelomic epithelium of the mesentery and gut anlage.…”

“…This distinguishes TIMPs in echinoderms from TIMPs in vertebrates. In addition, echinoderms have several TIMP-like proteins, in which not one, but two, or even three amino acid residues are located between the first and second cysteines at the N-terminus ( Figure 7 ) [ 35 , 78 , 79 ]. Some TIMP-like proteins lack the C-X-C motif and/or HPQ binding site ( Figure 7 ).…”

“…It was assumed that such proteins are present in all echinoderms and are an important component of the mechanism of regulation of MCT properties [ 82 , 132 ]. However, phylogenetic analysis showed that all identified tensilin-like proteins belong to members of relatively young groups of holothurians [ 35 , 79 ]. No similar proteins are found in Apodida and Elasipodida (the most ancient orders of holothurians [ 133 ]), or in other echinoderms.…”

“…Unlike mammals with only four TIMP s, some species of echinoderms can have up to 45 TIMP genes [ 78 ]. In the holothurians, it was shown that various MMPs and TIMPs were expressed in asexual reproduction and regeneration [ 19 , 35 , 64 , 79 ]. MMP blocking leads to a slowdown or full stop of morphogenesis [ 63 , 65 , 80 , 81 ].…”