Cell-substrate interactions in Cnidaria

Abstract

Studies on morphogenesis and regeneration in cnidarians have a long history, and the importance of cell‐ECM (extracellular matrix) interactions for these processes has been well recognized and studied since the middle of the 20th century. Cnidarians have a life cycle with a larva, a polyp, and often a medusa generation. In the medusa, the ECM (mesoglea) is very prominent and essentially shapes the animal. In the larva and the polyp, the ECM is a thin layer. Some of the ECM components known from vertebrates have been identified in cnidarians by immunohistochemistry, electron microscopy, rotary shadowing, biochemistry, and molecular cloning. In vivo and in vitro experiments suggest that the cnidarian ECM plays a role in cell migration and morphogenesis comparable to that known from other developmental systems. In the fresh water polyp Hydra, regeneration of body patterns and migration of nematocytes seems to require the presence of ECM ligands and the corresponding cell receptors. In hydrozoan medusae, DNA replication and the stability of the differentiated state of isolated tissue can be influenced by altering the properties of the ECM substrate. When cultured, most cnidarian cells survive only when attached to ECM substrates, they rarely divide and die within short times. Microsc. Res. Tech. 44:254–268, 1999. © 1999 Wiley‐Liss, Inc.

Scleractinian coral cell proliferation is reduced in primary culture of suspended multicellular aggregates compared to polyps

“…It is known that collagenase treatment of the extracellular matrix of cnidarian tissue may stimulate reprogramming and transdifferentiation of cell types, a process well described in the jellyfish (Scyphozoa) Podocoryne carnea (Schmid et al 1999;Schmid and Reber-Müller 1995). In the jellyfish, collagenase treatment of isolated pieces of the umbrella triggers de-differentiation of striated muscle cells, followed by transdifferentiation to smooth muscle cells.…”

The modulus of elasticity of fibrillin-containing elastic fibres in the mesoglea of the hydromedusaPolyorchis penicillatus

“…It is however possible that there is a matrix material present in the elastic fibres, which did not stain in Weber andSchmid's preparation. Reber-Müller et al (1995, 1996) suggested this possibility, although Schmid et al (1999) suggested that the microfibrils alone were responsible for the observed elasticity of the fibres. It seems more likely that the functionally continuous model is correct, particularly given the high volume fraction and high degree of overlap of the microfibrils in the fibre and observations by several authors of irreversible transglutaminase-derived crosslinks between fibrillin-rich microfibrils in several systems (Thurmond and Trotter, 1996;Qian and Granville, 1997;Schittny et al, 1997;Kielty et al, 2002).…”

“…Indeed, Schmid et al (1999) suggest that the elasticity in jellyfish radial fibres could be accounted for solely by the fibrillin microfibrils without the need for an elastin analogue. However, Sherratt et al (2003) used a molecular combing technique to measure the stiffness of individual fibrillin microfibrils to be 78-96·MPa, nearly two orders of magnitude greater than the stiffness of the microfibril-rich fibres studied to date (~1·MPa).…”

Components, structure, biogenesis and function of the Hydra extracellular matrix in regeneration, pattern formation and cell differentiation

“…A similar observation has been reported for Hydra metalloproteinase-1 that is localized to the tentacle ECM and has been shown to be involved in the maintenance of tentacle battery cell phenotypic markers . As reviewed by Schmid et al,1999), the importance of cell-ECM interactions during morphogenesis and cell differentiation extends beyond Hydra to a number of classes within Cnidaria. Finally, and most recently, a new in vivo labelling technique for Hydra collagen 1 and laminin was used to track the fate of ECM in all body regions of the animal (Aufschnaiter et al, 2011).…”