Possible Mechanisms of Stiffness Changes Induced by Stiffeners and Softeners in Catch Connective Tissue of Echinoderms

Abstract

The catch connective, or mutable collagenous, tissue of echinoderms changes its mechanical properties in response to stimulation. The body wall dermis of sea cucumbers is a typical catch connective tissue. The dermis assumes three mechanical states: soft, standard, and stiff. Proteins that change the mechanical properties have been purified from the dermis. Tensilin and the novel stiffening factor are involved in the soft to standard and standard to stiff transitions, respectively. Softenin softens the dermis in the standard state. Tensilin and softenin work directly on the extracellular matrix (ECM). This review summarizes the current knowledge regarding such stiffeners and softeners. Attention is also given to the genes of tensilin and its related proteins in echinoderms. In addition, we provide information on the morphological changes of the ECM associated with the stiffness change of the dermis. Ultrastructural study suggests that tensilin induces an increase in the cohesive forces with the lateral fusion of collagen subfibrils in the soft to standard transition, that crossbridge formation between fibrils occurs in both the soft to standard and standard to stiff transitions, and that the bond which accompanies water exudation produces the stiff dermis from the standard state.

Antitumor Properties of Matrikines of Different Origins: Prospects and Problems of Their Application

“…It is believed that the regular use of holothurian (trepang) Apostichopus japonicus rejuvenates the body, which is often associated with the unique properties of mutable collagen tissues (MCTs) of holothurians, which, when life is threatened, make their body rigid and, if necessary, jelly-like. MCT echinoderms can represent an innovative source of collagen to develop collagen barrier membranes for Guided Tissue Regeneration, a technique for restoring bone tissue, originally developed for periodontal surgery and now widely used in dental implantology [49,50].…”

“…Still, the molecular mechanism of the change in stiffness is not fully understood. Therefore, understanding the mechanisms of MCT quantitatively may have applications in the development of new types of mechanically tunable biomaterials (Figure 3) [49,50].…”

“…body, which is often associated with the unique properties of mutable collagen tissues (MCTs) of holothurians, which, when life is threatened, make their body rigid and, if necessary, jelly-like. MCT echinoderms can represent an innovative source of collagen to develop collagen barrier membranes for Guided Tissue Regeneration, a technique for restoring bone tissue, originally developed for periodontal surgery and now widely used in dental implantology [49,50]. Tensilin, a tissue stiffener, and softenin, a tissue softener, acting directly on the ECM, have been purified from the dermis of sea cucumbers, which is a typical catch connective tissue.…”

“…Still, the molecular mechanism of the change in stiffness is not fully understood. Therefore, understanding the mechanisms of MCT quantitatively may have applications in the development of new types of mechanically tunable biomaterials (Figure 3) [49,50]. For this reason, the studies of the antitumor properties of echinoderm MKs obtained by enzymatic hydrolysis with a complex of proteolytic enzymes Collagenase KK from the hepatopancreas of the king crab Paralithodes camtschatica are of particular interest.…”

Extracellular Matrix of Echinoderms

“…Echinoderms use this ability for maintaining a posture (the catch state) [4,5], in case of autotomy [6,7], and in asexual reproduction [8][9][10][11]. Nevertheless, to date, the mechanisms changing the ECM strength and the substances involved are incompletely known [12,13].…”