DISCORDANT REPROGRAMMING OF LPS-STIMULATED CYTOKINE GENE-TRANSCRIPTION AND SECRETION BY MACROPHAGES AFTER LPS PRETREATMENT

Dysregulated macrophage (M phi) cytokine release occurs during systemi c inflammation and may predispose to organ failure. We showed that M p hi s pretreated (PreRx) in vitro with low-dose LPS(p) are ''reprogramm ed'' to release less TNF and more IL-1 in response to subsequent LPS a ctivation (LPS(a)). The effects of this LPS(p) ''reprogramming'' on M phi cytokine gene transcription were investigated in the present study . Murine peritoneal exudate M phi s were cultured in vitro 48 hr, then PreRx 24 hr +/- 100 ng/ml of LPS(p). Cultures were stimulated with 0- 1000 ng/ml LPS(a) and 6-hr supernatant TNF and IL-1 were measured usin g specific bioassays. Cytokine gene transcription was estimated 6 hr a fter LPS(a) using RT-PCR. PreRx with LPS(p) inhibited TNF and augmente d IL-1 release by LPS(a). PreRx with LPS, significantly inhibited cyto kine gene transcription; however, messages for both TNF and IL-1 were detectable after high-dose LPS(a). Despite LPS(p) inhibition of IL-1 t ranscription by most LPS(a) concentrations, IL-1 protein was augmented by PreRx. High-dose LPS(a) can override LPS(p) reprogrammed inhibitio n of cytokine gene transcription, but altered TNF and IL-1 protein rel ease after LPS(p) may be regulated posttranscriptionally. (C) 1996 Aca demic Press, Inc.