Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro/RJ, Brazil.
Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro/RJ, Brazil.
PLoS Pathog. 2019 Jun 24;15(6):e1007887. doi: 10.1371/journal.ppat.1007887. eCollection 2019 Jun.
Leishmaniasis is a neglected tropical disease affecting millions of individuals worldwide. P2X7 receptor has been linked to the elimination of Leishmania amazonensis. Biological responses evoked by P2X7 receptor activation have been well-documented, including apoptosis, phagocytosis, cytokine release, such as IL-1β. It was demonstrated that NLRP3 inflammasome activation and IL-1β signaling participated in resistance against L. amazonensis. Furthermore, our group has shown that L. amazonensis elimination through P2X7 receptor activation depended on leukotriene B4 (LTB4) production and release. Therefore, we investigated whether L. amazonensis elimination by P2X7 receptor and LTB4 involved NLRP3 inflammasome activation and IL-1β signaling. We showed that macrophages from NLRP3-/-, ASC-/-, Casp-1/11-/-, gp91phox-/- , and IL-1R-/- mice treated with ATP or LTB4 did not decrease parasitic load as was observed in WT mice. When ASC-/- macrophages were treated with exogenous IL-1β, parasite killing was noted, however, we did not see parasitic load reduction in IL-1R-/- macrophages. Similarly, macrophages from P2X7 receptor-deficient mice treated with IL-1β also showed decreased parasitic load. In addition, when we infected Casp-11-/- macrophages, neither ATP nor LTB4 were able to reduce parasitic load, and Casp-11-/- mice were more susceptible to L. amazonensis infection than were WT mice. Furthermore, P2X7-/- L. amazonensis-infected mice locally treated with exogenous LTB4 showed resistance to infection, characterized by lower parasite load and smaller lesions compared to untreated P2X7-/- mice. A similar observation was noted when infected P2X7-/- mice were treated with IL-1β, i.e., lower parasite load and smaller lesions compared to P2X7-/- mice. These data suggested that L. amazonensis elimination mediated by P2X7 receptor and LTB4 was dependent on non-canonical NLRP3 inflammasome activation, ROS production, and IL-1β signaling.
利什曼病是一种被忽视的热带病，影响着全球数百万人。P2X7 受体与消灭亚马逊利什曼原虫有关。P2X7 受体激活引发的生物学反应已有详细记录，包括细胞凋亡、吞噬作用、细胞因子释放，如白细胞介素 1β（IL-1β）。已经证明，NLRP3 炎性体激活和 IL-1β 信号参与了对亚马逊利什曼原虫的抵抗。此外，我们的研究小组已经表明，通过 P2X7 受体激活消灭亚马逊利什曼原虫依赖于白三烯 B4（LTB4）的产生和释放。因此，我们研究了 P2X7 受体和 LTB4 通过何种方式消灭亚马逊利什曼原虫与 NLRP3 炎性体激活和 IL-1β 信号有关。我们发现，用 ATP 或 LTB4 处理的 NLRP3-/-、ASC-/-、Caspase-1/11-/-、gp91phox-/-和 IL-1R-/-小鼠的巨噬细胞寄生虫载量没有像野生型（WT）小鼠那样减少。当 ASC-/-巨噬细胞用外源性 IL-1β处理时，寄生虫被消灭，但在 IL-1R-/-巨噬细胞中未观察到寄生虫载量减少。同样，用 IL-1β 处理 P2X7 受体缺陷型小鼠的巨噬细胞也导致寄生虫载量减少。此外，当我们感染 Caspase-11-/-巨噬细胞时，ATP 或 LTB4 都不能降低寄生虫载量，并且 Caspase-11-/-小鼠比 WT 小鼠更容易感染亚马逊利什曼原虫。此外，用外源性 LTB4 局部治疗 P2X7-/-感染的亚马逊利什曼原虫的小鼠表现出对感染的抵抗，表现为与未治疗的 P2X7-/-小鼠相比，寄生虫载量较低，病变较小。在感染 P2X7-/-小鼠时用 IL-1β 处理也观察到类似的结果，即与 P2X7-/-小鼠相比，寄生虫载量较低，病变较小。这些数据表明，P2X7 受体和 LTB4 介导的亚马逊利什曼原虫的消灭依赖于非经典 NLRP3 炎性体激活、ROS 产生和 IL-1β 信号。
