CD36 antisense expression in 3T3-F442A preadipocytes is associated with low rates of both fatty acid transport and preadipocyte differentiation

An adipocyte membrane glycoprotein, homologous to human CD36, has been implicated in the binding/transport of long chain fatty acids (FA). The protein FAT was isolated from rat adipocytes by following the binding of a reactive derivative of oleic acid which specifically inhibited FA transport. In this study, we have examined the effect of CD36 antisense expression in 3T3-F442A on FA uptake and on differentiation into adipocytes. F442A cells were transfeeted with a pSG5-TAF vector obtained by insertion of the antisense coding sequence of CD36 into pSG5. Four clones were isolated based on expression of antisense CD36 mRNA. Levels of CD36 protein were determined by flow cytometry and were correlated with rates of eleate uptake. Three clones, TAF38, 25 and 13 exhibited low to undetectable CD36 expression and one clone TAF18 had comparable expression to F442A control cells. FA uptake rates in clones 38, 25 and 13 were lower than those observed in TAF18 or control. At confluence, adipocyte differentiation could be promoted by addition of insulin and triiodothyronine only in TAF18 cells but not in TAF38, 25 or 13. Treatment of cells at confluence for 60 hrs with bromopalmitate induced CD36 in TAF13 and 38 clones. This was correlated with an increase in FA uptake and in differentiation of the cells after removal of the bromopalmitate. The data support a role of CD36 in the membrane uptake of long chain FA. CD36 expression and FA uptake appear to be closely linked to preadipocyte differentiation but the precise relationship remains to be defined.