Molecular characterization of fibroblast growth factor-16 and its role in promoting the differentiation of intramuscular preadipocytes in goat

摘要

Fat metabolism is an important and complex biochemical reactionin vivoand is regulated by many factors. Recently, the findings on high expression of fibroblast growth factor-16 (FGF16) in brown adipose tissue have led to an interest in exploring its role in lipogenesis and lipid metabolism. The study cloned the goat'sFGF16 gene 624 bp long, including the complete open reading frame that encodes 207 amino acids. We found thatFGF16 expression is highest in goat kidneys and hearts, followed by subcutaneous fat and triceps. Moreover, the expression ofFGF16 reached its peak on the 2nd day of adipocyte differentiation (P< 0.01) and then decreased significantly. We used overexpression and interference to study the function ofFGF16 gene in goat intramuscular preadipocytes. Silencing ofFGF16 decreased adipocytes lipid droplet aggregation and triglyceride synthesis. This is in contrast to the situation whereFGF16 is overexpressed. Furthermore, knockdown ofFGF16 also caused down-regulated expression of genes associated with adipocyte differentiation including CCAAT enhancer-binding protein beta (P< 0.01), fatty acid-binding protein-2 (P< 0.01) and sterol regulatory element binding protein-1 (P< 0.05), but the preadipocyte factor-1 was up-regulated. At the same time, the genes adipose triglyceride lipase (P< 0.01) and hormone-sensitive lipase (P< 0.05) associated with triglyceride breakdown were highly expressed. Next, we locked the fibroblast growth factor receptor-4 (FGFR4) through the protein interaction network and interfering withFGF16 to significantly reduceFGFR4 expression. It was found that the expression profile ofFGFR4 in adipocyte differentiation was highly similar to that ofFGF16. Overexpression and interference methods confirmed thatFGFR4 andFGF16 have the same promoting function in adipocyte differentiation. Finally, using co-transfection technology, pc-FGF16 and siRNA-FGFR4, siRNA2-FGF16 and siRNA-FGFR4 were combined to treat adipocytes separately. It was found that in the case of overexpression ofFGF16, cell lipid secretion and triglyceride synthesis showed a trend of first increase and then decrease with increasing interference concentration. In the case of interference withFGF16, lipid secretion and triglyceride synthesis showed a downward trend with the increase of interference concentration. These findings illustrated thatFGF16 mediates adipocyte differentiation via receptorFGFR4 expression and contributed to further study of the functional role ofFGF16 in goat fat formation.