A role for protein kinase C activity in interleukin-1 (IL-1) induction of IL-2 gene expression but not in IL-1 signal transduction.

Abstract

Interleukin-1 (IL-1) is known to synergize with phorbol esters in the induction of interleukin-2 (IL-2) expression in T-lymphoid leukemia cells and proliferation of mouse thymocytes. We used a plasmid construct containing the bacterial gene for chloramphenicol acetyltransferase under the control of the human IL-2 promoter to study the nature of this synergism in the murine thymoma cell line EL4. Although IL-1 induction of the IL-2 promoter in these cells required costimulus with phorbol myristate acetate, the signal induced by IL-1 was qualitatively different. We provide evidence to support the hypothesis that the phorbol ester signal is mediated by protein kinase C, and we show that the IL-1 signal is not. That IL-1 and phorbol myristate acetate represent different stimuli was shown by their response to protein kinase C inhibitors, capacity to synergize with increased intracellular free calcium, and requirement for protein synthesis. In addition we show that pretreatment with IL-1 can prime EL4 cells to subsequent activation by concentrations of phorbol esters not normally sufficient to induce IL-2 expression. Pretreated cells remained primed for at least 40 h after removal of the IL-1. Neither phorbol myristate acetate nor a calcium ionophore was capable of preactivating EL4 cells.

Interleukin-1 beta modulates the growth and phenotype of neonatal rat cardiac myocytes.

“…The effects of inflammatory cytokines on cardiac myocyte growth and gene expression are not known. However, in hematopoietic, vascular smooth muscle and endothelial cells, inflammatory cytokines exert pleiotropic effects on cell growth, differentiation, and gene expression (2)(3)(4), and many of the signaling pathways activated by cytokines (5,6) are known to be involved in regulating growth and gene expression in cardiac myocytes (7). In addition, cytokines induce nitric oxide (NO)' production by upregulating expression of inducible nitric oxide synthase in cardiac myocytes (8,9) and could therefore act via cGMP, which has been shown to modulate growth in vascular smooth muscle cells (10).…”

“…The resultant cell suspension was cultured for 24 h in DME/FBS/PS with 0.1 mM Bromodeoxyuridine (Sigma Chemical Co., St. Louis, MO) to prevent proliferation of nonmyocytes. The medium was changed to serum-free medium containing insulin (5 pg/ml), transferrin (5 To confirm that L-NMMA inhibited NO production, cGMP levels were used as markers of IL-iI -induced NO synthesis. Myocyte cGMP content was measured using a standard radioimmunoassay kit (Biomedical Technologies, Inc., Stoughton, MA) (18).…”

p21ras contributes to HIV‐1 activation in T‐cells

“…An approximately 1.7 kb fragment from the EcoRV site i,a the pUC18 polylinker to the Hb~dill site at map position 1.71 of the HIV-I LTR was excised from the plasmid, pNL4-3 [31], and subcloned upstream or the CAT gone in the plasmid, IL2-CAT [32], digested with Hindlll and Sinai to remove the IL-2 promoter flagment, pSVT7 is an expression vector containing a polylinker downstream of the SV40 earl)' promoter [33], pSVT7/IL.IR has been described elsewhere [341.…”

“…The medium used for tranffeclions ineluded 200 U/ml penicillin (Farmitalia, Italy). Transfections were carried oat using a modification of the DEAE .dcxtran procedure, as described [20], scaled dowl~ to one tenth with 1 /.tg of the plasmid L'rR/CAT per sample (1×10" Jurkat cells). To avoid error due to variation in transfeetion efficiency, comparisons of stimuli or inhibitors were carried out on identical aliquots of single pools of transfectecl ceils.…”

“…Several intracellular signalling pathways, including mobilization of both monovalent and divalent ions [13,14] and aeti. ration of several protein kinases [15][16][17], are involved in T-cell activation, however, activation of protein kinase C (PKC) [18][19][20] and mobilization of calcium by the TCR [21][22][23][24] have been shown to be necessary. These two signals in combination with a less-well defined but independent signal, which can be delivered by the lymphokine IL-1 [25], are sufficient to induce full IL-2 and IL-2R expression.…”