Breed difference and regulation of the porcine adipose triglyceride lipase and hormone sensitive lipase by TNFalpha.

Adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) are major novel triglyceride lipases in animals. The aim of this study was to determine if there are differences in the porcine ATGL (pATGL) and HSL genes between Jinhua pigs (a fatty breed) and Landrace pigs (a leaner breed). In addition, the effect of TNFalpha and pATGL-specific siRNA (pATGL-siRNA) on the expression of pATGL and HSL in porcine adipocytes was also examined. Compared with Landrace pigs, the body weight (BW) of Jinhua pigs was lower (P < 0.01), while intramuscular fat content (in the longissimus dorsi muscle), as well as the back fat thickness and body fat content were higher (P < 0.01). The expression of pATGL and HSL mRNA in Jinhua pigs was lower (P < 0.01) in subcutaneous adipose tissue, and greater (P < 0.01) in longissimus dorsi muscle compared with Landrace pigs. In vitro treatment of porcine adipocytes with TNFalpha decreased (P < 0.01) the glycerol release and the gene expression of pATGL, HSL and PPARgamma in porcine adipocytes. Furthermore, transfection with pATGL-siRNA significantly decreased (P < 0.01) the expression of pATGL, while it had no effect on the expression of HSL. Treatment with 25 ng/ml TNFalpha in conjunction with pATGL-siRNA significantly decreased (P < 0.01) the expression of pATGL and HSL in cultured porcine adipocytes. These results provide useful information to further the understanding of the function of pATGL and HSL in porcine lipid metabolism, which should be applicable to the regulation of fat deposition and improvement of meat quality.