A new cruzipain-mediated pathway of human cell invasion by Trypanosoma cruzi requires trypomastigote membranes
A new cruzipain-mediated pathway of human cell invasion by Trypanosoma cruzi requires trypomastigote membranes
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DOI：
10.1128/iai.72.10.5892-5902.2004
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发表时间：
2004-10-01
影响因子：
3.1
通讯作者：
Lima, APCA
中科院分区：
文献类型：
--
作者：
Aparicio, IM;Scharfstein, J;Lima, APCA
细胞内的原生动物克氏锥虫引起恰加斯病，这是一种与心肌病和消化系统疾病有关的慢性疾病。这种病原体通过多种转导途径向哺乳动物细胞发出信号，从而侵入哺乳动物细胞。我们以前的研究表明，T. Cruzi通过激活激肽受体促进宿主细胞侵袭。在这里，我们报告了一个cruzipain介导的入侵途径，是不阻断激肽受体拮抗剂。通过对不同菌株T. Cruzi，我们观察到锥鞭毛体分泌的Cruzipain水平与病原体侵入宿主细胞的能力之间的相关性。与cruzipain的作用一致，半胱氨酸蛋白酶抑制剂N-甲基哌嗪-脲-苯丙氨酸-高苯丙氨酸-乙烯砜-苯通过菌株Dm 28 c和X10/6而不是通过G分离物损害人平滑肌细胞的侵袭。Cruzipain丰富的DM 28 C锥鞭毛体的上清液增强了隔离G寄生虫的感染性的两倍，半胱氨酸蛋白酶抑制剂L-trans-epoxysuccinyl-leucylamido-（4-guanidino）丁烷和毒胡萝卜素，一种药物，诱导细胞内Ca 2+商店的耗尽，这是废除的效果。在cruzipain免疫耗竭后，由于Dm 28上清液的增强被消除，并且通过纯化的cruzipain恢复活性。相反，来自分离的G锥鞭毛体的上清液（具有低水平的cruzipain）或来自Dm 28 c外鞭毛体的上清液或单独的纯化的cruzipain不增强寄生虫侵袭，表明蛋白酶是必需的，但不足以参与该侵袭途径。我们提供的证据表明，该途径的激活需要克鲁兹蛋白酶介导的与寄生虫脱落膜相关的锥虫鞭虫分子的加工。我们的研究结果夫妇cruzipain宿主细胞入侵通过激肽的独立途径，并进一步表明，高水平cruzipain表达可能有助于寄生虫的感染性。
The intracellular protozoan Trypanosoma cruzi causes Chagas' disease, a chronic illness associated with cardiomyopathy and digestive disorders. This pathogen invades mammalian cells by signaling them through multiple transduction pathways. We previously showed that cruzipain, the main cysteine protease of T. cruzi, promotes host cell invasion by activating kinin receptors. Here, we report a cruzipain-mediated invasion route that is not blocked by kinin receptor antagonists. By testing different strains of T. cruzi, we observed a correlation between the level of cruzipain secreted by trypomastigotes and the capacity of the pathogen to invade host cells. Consistent with a role for cruzipain, the cysteine protease inhibitor N-methylpiperazine-urea-Phe-homophenylalanine-vinylsulfone-benzene impaired the invasion of human smooth muscle cells by strains Dm28c and X10/6 but not by the G isolate. Cruzipain-rich supernatants of Dm28c trypomastigotes enhanced the infectivity of isolate G parasites twofold, an effect which was abolished by the cysteine protease inhibitor L-trans-epoxysuccinyl-leucylamido-(4-guanidino) butane and by thapsigargin, a drug that induces depletion of the intracellular Ca2+ stores. The enhancement due to Dm28 supernatants was abolished upon cruzipain immunodepletion, and the activity was restored by purified cruzipain. In contrast, supernatants from isolate G trypomastigotes (with low levels of cruzipain) or supernatants from Dm28c epimastigotes or purified cruzipain alone did not enhance parasite invasion, indicating that the protease is required but not sufficient to engage this invasion pathway. We provide evidence that activation of this pathway requires cruzipain-mediated processing of a trypomastigote molecule associated with parasite-shed membranes. Our results couple cruzipain to host cell invasion through a kinin-independent route and further suggest that high-level cruzipain expression may contribute to parasite infectivity.