Biocompatibility assessment of type-II collagen and its polypeptide for tissue engineering: effect of collagen's molecular weight and glycoprotein content on tumor necrosis factor (Fas/Apo-1) receptor activation in human acute T-lymphocyte leukemia cell line
Low molecular weight (LMW) (57, 40 and 25 kDa) collagens were separated and Fas cell surface death receptor activation were investigated based on its MW and glycoprotein content. The biochemical properties such as amino acid profile, FTIR and glycoprotein content of LMW collagens were slightly different and confirmed that limited digestion by proteolytic enzyme disrupted the triple helical structure of collagen. Cell adhesion pattern between collagens and immune cells were dose dependent manner. Better active cellular suppression of fish collagen than mammalian collagen was confirmed by increased secretion of immunological indexes (FAS/APO-1, cytokines (IL-2, IL-6) and caspases (casp-3, casp-8)) in T cell. Apoptotic regulatory gene expression (FAS, FAS-L, CASp-3, CASP-8, IL-2 and IL-6) of 6T-CEM cells was further confirmed the biocompatibility of fish collagens. Fluorescence microstructure revealed destruction of immune cells morphology and nuclei due to apoptosis by fish collagens. Consequently, this study disclosed that the apoptosis induction in T cells was based on the MW of collagens and also attachment of glycoprotein with tumor necrosis factor receptor (TNFRSF6) in cell membrane, which further activates DD, FAD, DED and caspase cascade pathway. Accordingly, this study created new platform for the better use of fish collagen in biomedical industries for the treatment of autoimmune diseases.