Colotta F, Sciacca F L, Sironi M, Luini W, Rabiet M J, Mantovani A
Centro Daniela e Catullo Borgomainerio, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Am J Pathol. 1994 May;144(5):975-85.
Thrombin, in addition to being a key enzyme in hemostasis, affects a series of endothelial and leukocyte functions and thus may be involved in the regulation of inflammatory reactions. Because leukocyte recruitment and activation are important events in inflammatory and thrombotic processes, in this study we have examined the possibility that thrombin induces the production of a cytokine chemotactic for mononuclear phagocytes. Human peripheral blood mononuclear cells (PBMC) exposed in vitro to thrombin expressed transcripts of monocyte chemotactic protein-1 (MCP-1; alternative acronyms: JE, monocyte chemotactic and activating factor, tumor-derived chemotactic factor). Thrombin was two- to threefold less effective than endotoxin in inducing MCP-1 transcripts in PBMC. Among circulating mononuclear cells, monocytes were identified as the cells expressing MCP-1 in response to thrombin. Monocytes expressed thrombin receptor transcripts. Boiling, hirudin, antithrombin III, and mutation of the catalytic site serine 205 into alanine) blocked the capacity of thrombin to induce MCP-1 expression. The thrombin receptor-activating peptide mimicked the effect of thrombin in inducing MCP-1 expression. Induction of MCP-1 transcript by thrombin was not reduced by blocking interleukin-1 and tumor necrosis factor, suggesting that these mediators are not involved in thrombin-induced expression of MCP-1. In addition to monocytes, endothelial cells (EC) also expressed MCP-1 in response to thrombin, although at lower levels compared with monocytes. Actinomycin D experiments indicated that induction of MCP-1 by thrombin in PBMC and EC was gene transcription dependent. The inhibition of protein synthesis blocked thrombin-induced MCP-1 expression in PBMC, whereas it superinduced both constitutive and thrombin-inducible expression of MCP-1 in EC, indicating different mechanisms of regulation of this gene in mononuclear phagocytes versus endothelial cells. Thrombin stimulated mononuclear cells and EC to release chemotactic activity for monocytes that could be inhibited by absorption with anti-MCP-1 antibodies. Induction of a chemotactic cytokine for monocytes by thrombin points to the importance of this enzyme in regulating inflammatory processes and further indicates that hemostasis, inflammation, and immunity are strictly interconnected processes.
凝血酶不仅是止血过程中的关键酶，还会影响一系列内皮细胞和白细胞的功能，因此可能参与炎症反应的调节。由于白细胞募集和激活是炎症和血栓形成过程中的重要事件，在本研究中，我们探讨了凝血酶是否能诱导产生对单核吞噬细胞具有趋化作用的细胞因子。体外暴露于凝血酶的人外周血单个核细胞（PBMC）表达单核细胞趋化蛋白-1（MCP-1；别名：JE、单核细胞趋化和激活因子、肿瘤衍生趋化因子）的转录本。在诱导PBMC中MCP-1转录本方面，凝血酶的效力比内毒素低两到三倍。在循环单核细胞中，单核细胞被确定为响应凝血酶而表达MCP-1的细胞。单核细胞表达凝血酶受体转录本。煮沸、水蛭素、抗凝血酶III以及将催化位点丝氨酸205突变为丙氨酸均阻断了凝血酶诱导MCP-1表达的能力。凝血酶受体激活肽模拟了凝血酶诱导MCP-1表达的作用。阻断白细胞介素-1和肿瘤坏死因子并不会降低凝血酶诱导的MCP-1转录本，这表明这些介质不参与凝血酶诱导的MCP-1表达。除了单核细胞外，内皮细胞（EC）也会响应凝血酶表达MCP-1，不过与单核细胞相比水平较低。放线菌素D实验表明，凝血酶在PBMC和EC中诱导MCP-1是依赖基因转录的。蛋白质合成的抑制阻断了凝血酶在PBMC中诱导的MCP-1表达，而在EC中它却超诱导了MCP-1的组成型和凝血酶诱导型表达，这表明该基因在单核吞噬细胞和内皮细胞中的调节机制不同。凝血酶刺激单核细胞和EC释放对单核细胞具有趋化活性的物质，这种活性可被抗MCP-1抗体吸收所抑制。凝血酶诱导产生对单核细胞具有趋化作用的细胞因子，这表明该酶在调节炎症过程中具有重要性，进一步表明止血、炎症和免疫是紧密相连的过程。
