Acylphosphatase expression during macrophage differentiation and activation of U-937 cell line

The two acylphosphatase isoenzymes (muscle type and common type) are differ ently involved in cell differentiation processes. In this paper we investig ate the expression of the two isoenzymes during macrophage differentiation and activation. The U-937 human promonocytic cell line is a model for cell differentiation induced by the tumor promoter phorbol myristic acetate (PMA ). Here we show that only the expression of the muscle type acylphosphatase increases during U-937 differentiation and macrophage activation, confirmi ng that the two isoenzymes are differently regulated. Moreover, we determin ed, in the same conditions, the level of specific mRNA. Results show that a fter an initial two-fold decrease during PMA stimulation, the muscle type a cylphosphatase mRNA levels remain constant also after the treatment with li popolysaccharide and gamma-interferon, treatments that lead to macrophage a ctivation. It is possible that post-transcription regulation is responsible for the regulation of muscle type acylphosphatase in the cell during diffe rentiation and macrophage activation. (C) Societe francaise de biochimie et biologie moleculaire/Editions scientifiques et medicales Elsevier SAS.