STIMULATION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 EXPRESSION BY CERAMIDE

Ceramide, an intracellular lipid mediator of tumor necrosis factor alp ha (TNF-alpha) action, was studied for its effects on the expression o f the proviral human immunodeficiency virus type 1 genome in latently infected myelomonocytic cell lines U-1(IIIB) and OM-10.1. Ceramide tre atment resulted in a 20- to 100-fold enhancement of HIV production in these cells. Ceramide also enhanced the expression of the chlorampheni col acetyltransferase gene directed by a human immunodeficiency virus type 1 long terminal repeat in transfected U-937 cells, indicating tha t ceramide acts at the level of viral transcription. These observation s suggest that the TNF-ceramide signaling system may be involved in th e regulation of HIV expression in certain myeloid cell types.