Collagen of Extracellular Matrix from Marine Invertebrates and Its Medical Applications

Abstract

The extraction and purification of collagen are of great interest due to its biological function and medicinal applications. Although marine invertebrates are abundant in the animal kingdom, our knowledge of their extracellular matrix (ECM), which mainly contains collagen, is lacking. The functions of collagen isolated from marine invertebrates remain an untouched source of the proteinaceous component in the development of groundbreaking pharmaceuticals. This review will give an overview of currently used collagens and their future applications, as well as the methodological issues of collagens from marine invertebrates for potential drug discovery.

Keywords: chitin; collagen; corals; extracellular matrix; marine invertebrates; marine proteins.

Figure 1

Marine calcifiers and their collagens. (A) Examples of marine calcifiers/invertebrates. (B) A model image on the biological synthesis of collagens from the marine invertebrates and crustose coralline algae.

Figure 2

Collagen of extracellular matrix and its biology in invertebrates. The right panel shows a model of cells. The left panel shows the structural components of the extracellular matrix, which are involved in the formation of collagen in marine invertebrates.

Figure 3

Collagen associated glycoproteins in marine calcifiers. Coralline red algae: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with a periodic acid-schiff (PAS) staining to detect glycoprotein in the extracellular matrix of Clathromorphum compactum. M, protein ladder. Lane 1 and 2, high molecular weight (250 kDa) of a glycoprotein. Soft coral (Sinularia polydactyla): SDS-PAGE with a PAS staining to detect glycoprotein in the extracellular matrix of S. polydactyla. M, protein ladder. Two glycoproteins (83 and 63 kDa) were identified in this species. Soft Coral (Lobophytum crassum): SDS-PAGE with a PAS staining. The PAS staining to detect glycoprotein in the extracellular matrix of L. crassum. M, protein ladder. Two glycoproteins (102 and 67 kDa) were identified in this soft coral species. The Precision Plus SDS-PAGE protein ladder (Bio-Rad) was used for the electrophoresis analysis of all above-mentioned glycoproteins. The glycoproteins presented here were reproduced from Rahman [5] for the coralline red algae and Rahman et al. [25] for the two soft corals (S. polydactyla, L. crassum).

Figure 4

X-ray diffraction (XRD) analysis of C. compactum. The 2θ scan identifies the mineral form of CaCO₃ crystal planes, which were nucleated by chitin and collagen matrices. Purple arrows show the collagen bands. Reproduced with permission from Rahman and Halfar [9].

Figure 5

Infrared (IR) of collagens in C. compactum. Attenuated total reflection (ATR)–Fourier–transform infrared spectroscopy (FTIR) spectra reveal the collagen bands in both soluble (A) and insoluble (B) organic matrix fractions. [Reproduced from Rahman and Halfar (9)].