Leishmania-induced inactivation of the macrophage transcription factor AP-1 is mediated by the parasite metalloprotease GP63.
Leishmania-induced inactivation of the macrophage transcription factor AP-1 is mediated by the parasite metalloprotease GP63.
复制标题
DOI：
10.1371/journal.ppat.1001148
复制
发表时间：
2010-10-14
期刊：
影响因子：
6.7
通讯作者：
Olivier M
中科院分区：
文献类型：
--
作者：
Contreras I;Gómez MA;Nguyen O;Shio MT;McMaster RW;Olivier M
利什曼原虫通过改变宿主细胞信号转导机制，包括抑制JAK/STAT信号传导和其他转录因子如AP-1、CREB和NF-κB，从而进化出复杂的机制来破坏巨噬细胞免疫应答。AP-1调节促炎细胞因子、趋化因子和一氧化氮的产生。在此，我们表明，利什曼原虫感染后，宿主细胞内的AP-1活性被废除，并与7个AP-1亚基中的5个亚基的低表达相关。有趣的是，AP-1的中心成分c-Jun被利什曼原虫切割。此外，c-Jun的切割依赖于主要利什曼原虫表面蛋白酶GP 63的表达和活性。从核提取物的c-Jun的免疫沉淀表明，GP 63相互作用，并在感染后不久在核周区域切割c-Jun。细胞松弛素D的吞噬抑制作用并没有阻止c-Jun下调，这表明寄生虫的内化可能不是在宿主细胞内传递GP 63分子所必需的。这一观察结果通过在与L. mexicana培养物上清液，表明分泌的可溶性GP 63可以使用吞噬作用非依赖性机制进入宿主细胞。甲基β-环糊精（MβCD）对巨噬细胞脂筏微区的破坏部分抑制了全长c-Jun的降解，我们的研究结果表明表面蛋白酶GP 63在利什曼原虫介导的宿主AP-1活性颠覆中的新作用。利什曼病是一种热带疾病，影响着全世界1200多万人。这种疾病是由利什曼原虫寄生虫引起的，当哺乳动物进食血液时，利什曼原虫寄生虫通过白蛉载体传播给哺乳动物宿主。寄生虫能够在细胞内生存和繁殖，这些细胞包括宿主的主要防御，巨噬细胞。我们已经广泛研究了利什曼原虫逃避巨噬细胞杀微生物功能的机制。在此，我们报告说，寄生虫可以通过降低转录因子的活性，如活化蛋白-1（AP-1），参与转录的基因编码的巨噬细胞的抗菌功能，从而使这些细胞。在这项研究中，我们发现利什曼原虫使用其最丰富的表面蛋白GP 63来识别AP-1转录因子。此外，我们发现，GP 63进入巨噬细胞独立于寄生虫内化使用富含脂质的微区定位在细胞膜。此外，观察到GP 63到达核区室，在那里它切割AP-1亚基蛋白。总的来说，我们的研究结果揭示了利什曼原虫用于促进其在哺乳动物宿主细胞内生存和繁殖的新机制。更好地了解这种病原体可以逃避先天免疫反应的机制可能有助于开发新的抗利什曼原虫疗法。
Leishmania parasites have evolved sophisticated mechanisms to subvert macrophage immune responses by altering the host cell signal transduction machinery, including inhibition of JAK/STAT signalling and other transcription factors such as AP-1, CREB and NF-κB. AP-1 regulates pro-inflammatory cytokines, chemokines and nitric oxide production. Herein we show that upon Leishmania infection, AP-1 activity within host cells is abolished and correlates with lower expression of 5 of the 7 AP-1 subunits. Of interest, c-Jun, the central component of AP-1, is cleaved by Leishmania. Furthermore, the cleavage of c-Jun is dependent on the expression and activity of the major Leishmania surface protease GP63. Immunoprecipitation of c-Jun from nuclear extracts showed that GP63 interacts, and cleaves c-Jun at the perinuclear area shortly after infection. Phagocytosis inhibition by cytochalasin D did not block c-Jun down-regulation, suggesting that internalization of the parasite might not be necessary to deliver GP63 molecules inside the host cell. This observation was corroborated by the maintenance of c-Jun cleavage upon incubation with L. mexicana culture supernatant, suggesting that secreted, soluble GP63 could use a phagocytosis-independent mechanism to enter the host cell. In support of this, disruption of macrophage lipid raft microdomains by Methyl β-Cyclodextrin (MβCD) partially inhibits the degradation of full length c-Jun. Together our results indicate a novel role of the surface protease GP63 in the Leishmania-mediated subversion of host AP-1 activity. Leishmaniasis is a tropical disease affecting more than 12 million people around the world. The disease is caused by the Leishmania parasites that are transmitted to the mammalian host by a sandfly vector when it takes a blood meal. The parasites are able to survive and multiply inside of cells that comprise the primary defence of the host, the macrophages. We have extensively studied the mechanism whereby Leishmania escapes from macrophage microbicidal functions. Herein we report that the parasite can inactivate these cells by decreasing the activity of transcription factors such as Activated Protein-1(AP-1) that are involved in transcription of genes coding for antimicrobial functions of macrophages. In this study, we showed that Leishmania parasites use their most abundant surface protein GP63 to inactivate the AP-1 transcription factor. Furthermore, we found that GP63 enter into the macrophages independently of parasite internalization using lipid rich microdomains localized in the cellular membrane. In addition, GP63 was observed to reach the nuclear compartment where it cleaves AP-1 subunit proteins. Collectively, our findings reveal a novel mechanism used by Leishmania to facilitate its survival and propagation within its mammalian host cells. Better knowledge concerning the mechanisms whereby this pathogen can escape the innate immune response may help to develop new anti-Leishmania therapy.
登录
查看更多内容
影响因子：
3.1
作者：
Ghosh, S;Bhattacharyya, S;Majumdar, S
通讯作者：
Majumdar, S
影响因子：
4
作者：
Hess, J;Angel, P;Schorpp-Kistner, M
通讯作者：
Schorpp-Kistner, M
影响因子：
4.4
作者：
Jaramillo, M;Olivier, M
通讯作者：
Olivier, M
影响因子：
5.8
作者：
Descoteaux, A;Turco, SJ
通讯作者：
Turco, SJ
影响因子：
2.9
作者：
BOUVIER, J;SCHNEIDER, P;BORDIER, C
通讯作者：
BORDIER, C