Cartilaginous fishes-derived chondroitin sulfates potentially suppress lipid droplet accumulation in the differentiated 3T3-L1 adipocytes.

In this study, we investigated for cell proliferative and adipogenic differentiation inhibitory activities of chondroitin sulfate (CS) from cartilaginous fish: mako shark (Isurus oxyrinchus, spine part, Ms-CS), blue shark (Prionace glauca, spine part, Bs-CS), sharpspine skate (Okamejei acutispina, head and tail parts, Sp-CS) and stingray (Dasyatis akajei, head part, St-CS) on 3T3-L1 cells. Most of the CSs from cartilaginous fish showed concentration-dependent cell proliferative activity of 3T3-L1 cells within the retrieved concentration range (0-1,000 μg/mL), while under induction of adipocyte differentiation, they inhibited lipid accumulation. In particular, Ms-CS and Sp-CS were highly active in inhibiting lipid accumulation in the cells. The present study revealed that cartilaginous fish-derived CS has inhibitory activity on 3T3-L1 adipocyte differentiation by suppressing lipid droplet accumulation, although the degree of suppression varied depending on the composition of the CS and its origin. In addition, a significant increase in chondroitin sulfate N-acetylgalactosaminyltransferase 2 (Csgalnact2) expression of the Sp-CS group at the concentration of 500 µg/mL was observed. Csgalnact2 expression is associated with chondroitin N-acetylgalactosaminyltransferase-2 (ChGn-2), one of the glycosyltransferases that catalyzes the chain initiation and elongation of the CS backbone in its biosynthesis. Exogenous CS from cartilaginous fishes increased Csgalnact2 expression, although further studies are needed to confirm changes in CS biosynthesis. We observed reduced lipid accumulation in differentiated 3T3-L1 cells. Our findings highlight the role of CS polysaccharides, in inhibiting adipogenesis, even though further investigation is required to understand the underlying mechanism.