IL-1 and TNF-α are induced in macrophages by LPS; however, it is unclear whether similar mechanisms control the expression of both genes. Here, we report on the detection of differential regulation of LPS induced IL-1 and TNF-α mRNA expression and protein production in murine macrophages based on the use of inhibitors of second messenger pathways. Northern blot analysis was performed with total RNA obtained from murine (C57Bl/6) peritoneal macrophages stimulated in vitro with LPS with or without an inhibitor of protein kinase C (PKc) (1-(5-isoquinolinesulfonyl)-2-methylpiperazine hydrochloride; H7) or an inhibitor of calmodulin (CaM)-dependent kinase (N-(6-amino-hexyl)-5-chloro-1-naphthalene-sulfonamide hydrochloride; W7). Northerns were analyzed with probes for IL-1α and IL-1β and TNF-α. The expression of the three cytokine mRNA by LPS was inhibited in a dose response manner by H7. In contrast, the expression of IL-1 mRNA, but not TNF-α mRNA, was blocked by treatment with W7. Parallel studies monitoring biologic activities of these two cytokines confirm the mRNA data. PKc inhibitors, H7 and retinal, block both IL-1 and TNF-α protein production and inhibitors of CaM kinase, W7, N-(6-aminobutyl)-5-chloro-2-naphthalenesulfonamide, calmidazolum, and trifluoperazine dichloride inhibit only IL-1 production. These data suggest that both PKc and CaM kinase dependent pathways are involved in the induction of IL-1 mRNA by LPS. In contrast, TNF-α expression appears to be PKc dependent but not CaM kinase dependent.
|Number of pages||5|
|Journal||Journal of Immunology|
|Publication status||Published - 1988|
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