Lake F R, Dempsey E C, Spahn J D, Riches D W
Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
Am J Physiol. 1994 Jan;266(1 Pt 1):C134-42. doi: 10.1152/ajpcell.1994.266.1.C134.
The expression of cytocidal activity is initiated by the interaction of macrophages with priming [e.g., interferon (IFN)] and triggering stimuli (polyinosinic-polycytidylic acid). We have shown that the triggering step can be initiated in a Ca(2+)-dependent fashion and hypothesized that protein kinase C (PKC) may couple the Ca2+ signal to the expression of a gene product, Bf, that accompanies the expression of macrophage cytocidal activity. Exposure of IFN-primed macrophages to polyinosinic-polycytidylic acid in the presence of the PKC inhibitors H-7 or sphingosine or after downregulation of PKC with phorbol myristate acetate markedly inhibited Bf synthesis. Western blots of macrophage lysates revealed the presence of the alpha-, delta-, and zeta-isozymes of PKC, and all were found to be downregulated by phorbol myristate acetate. Inhibition of PKC also prevented the increase in IFN-beta mRNA levels and partially blocked the response to IFN-beta. These data suggest that the alpha-, delta-, and zeta-isozymes of PKC are involved in signaling leading to Bf expression and that the level of involvement is restricted to the induction and response to IFN-beta.
细胞杀伤活性的表达是由巨噬细胞与启动因子[如干扰素（IFN）]和触发刺激物（聚肌苷酸-聚胞苷酸）相互作用引发的。我们已经表明，触发步骤可以以钙（Ca2+）依赖的方式启动，并推测蛋白激酶C（PKC）可能将Ca2+信号与一种基因产物Bf的表达相偶联，Bf伴随着巨噬细胞细胞杀伤活性的表达。在PKC抑制剂H-7或鞘氨醇存在的情况下，或者在用佛波酯肉豆蔻酸酯下调PKC后，将IFN启动的巨噬细胞暴露于聚肌苷酸-聚胞苷酸中，显著抑制了Bf的合成。巨噬细胞裂解物的蛋白质印迹显示存在PKC的α、δ和ζ同工酶，并且发现所有这些同工酶都被佛波酯肉豆蔻酸酯下调。PKC的抑制也阻止了IFN-β mRNA水平的增加，并部分阻断了对IFN-β的反应。这些数据表明，PKC的α、δ和ζ同工酶参与了导致Bf表达的信号传导，并且参与程度仅限于对IFN-β的诱导和反应。
