Endothelial differentiation gene-2 receptor is involved in lysophosphatidic acid-dependent control of 3T3F442A preadipocyte proliferation and spreading

EDG-2, EDG-4, EDG-7, and PSP24 genes encode distinct lysophosphatidic acid (LPA) receptors, The aim of the present study was to determine which receptor subtype is involved in the biological responses generated by LPA in preadipocytes, Growing 3T3F442A preadipocytes express EDG-2 and EDG-4 mRNAs, with no expression of EDG-7 or PSP24 mRNAs. Quantitative reverse transcriptase-polymerase chain reaction revealed that EDG-2 transcripts were 10-fold more abundant than that of EDG-4. To determine the involvement of the EDG-2 receptor in the responses of growing preadipocytes to LPA, stable transfection of antisense EDG-2 cDNA was performed in growing 3T3F442A preadipocytes. This procedure, led to a significant and specific reduction in EDG-2 mRNA and protein. This was associated with a significant alteration in the effect of LPA on both cell proliferation and cell spreading, Finally, the differentiation of growing preadipocytes into quiescent adipocytes led to a strong reduction in the level of EDG-2 transcripts. Results demonstrate the significant contribution of the EDG-2 receptor in the biological responses generated by LPA in 3T3F442A preadipocytes.