Effects of lysophosphatidic acid on the in vitro proliferation and differentiation of a novel porcine preadipocyte cell line

We examined the effects of lysophosphatidic acid (LPA) on in vitro proliferation and differentiation of a porcine preadipocyte cell line, DFAT-P, and a mouse preadipocyte cell line, 3T3-L1. During the proliferation and differentiation phases, DFAT-P and 3T3-L1 cells expressed only the endothelial differentiation gene (EDG)-2 receptor and not EDG-4 and EDG-7 receptors. LPA promoted the proliferation of DFAT-P cells more extensively than that of 3T3-L1 cells. After adipogenic induction, LPA inhibited glycerol-3-phosphate dehydrogenase activity and lipid droplet accumulation, and suppressed peroxisome proliferator-activated receptor γ (PPARγ) protein expression, this inhibitory effect in DFAT-P cells was twice as high as that in 3T3-L1 cells. Furthermore, treatments with low LPA concentrations significantly inhibited adipocyte differentiation in DFAT-P cells but not in 3T3-L1 cells. We conclude that LPA promotes the proliferation of porcine preadipocytes through the EDG-2 receptor but inhibits their differentiation, and these effects depend on the down-regulation of PPARγ expression via the EDG-2 receptor. Furthermore, DFAT-P cells are more sensitive to LPA than 3T3-L1 cells. These findings in a porcine model will contribute to the understanding of LPA action mechanisms on in vitro proliferation and differentiation of preadipocytes in domestic animals and/or humans.