半胱天冬酶-1/凋亡相关斑点样蛋白炎性小体介导的白细胞介素-1β-活性氧-核因子-κB途径对克氏锥虫复制和存活的控制在NLRP3基因敲除巨噬细胞中是不必要的。
Caspase-1/ASC inflammasome-mediated activation of IL-1β-ROS-NF-κB pathway for control of Trypanosoma cruzi replication and survival is dispensable in NLRP3-/- macrophages.
作者信息
Dey Nilay, Sinha Mala, Gupta Shivali, Gonzalez Mariela Natacha, Fang Rong, Endsley Janice J, Luxon Bruce A, Garg Nisha Jain
机构信息
Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, Texas, United States of America.
Department of BioChemistry & Molecular Biology, UTMB, Galveston, Texas, United States of America.
出版信息
PLoS One. 2014 Nov 5;9(11):e111539. doi: 10.1371/journal.pone.0111539. eCollection 2014.
In this study, we have utilized wild-type (WT), ASC-/-, and NLRP3-/- macrophages and inhibition approaches to investigate the mechanisms of inflammasome activation and their role in Trypanosoma cruzi infection. We also probed human macrophages and analyzed published microarray datasets from human fibroblasts, and endothelial and smooth muscle cells for T. cruzi-induced changes in the expression genes included in the RT Profiler Human Inflammasome arrays. T. cruzi infection elicited a subdued and delayed activation of inflammasome-related gene expression and IL-1β production in mφs in comparison to LPS-treated controls. When WT and ASC-/- macrophages were treated with inhibitors of caspase-1, IL-1β, or NADPH oxidase, we found that IL-1β production by caspase-1/ASC inflammasome required reactive oxygen species (ROS) as a secondary signal. Moreover, IL-1β regulated NF-κB signaling of inflammatory cytokine gene expression and, subsequently, intracellular parasite replication in macrophages. NLRP3-/- macrophages, despite an inability to elicit IL-1β activation and inflammatory cytokine gene expression, exhibited a 4-fold decline in intracellular parasites in comparison to that noted in matched WT controls. NLRP3-/- macrophages were not refractory to T. cruzi, and instead exhibited a very high basal level of ROS (>100-fold higher than WT controls) that was maintained after infection in an IL-1β-independent manner and contributed to efficient parasite killing. We conclude that caspase-1/ASC inflammasomes play a significant role in the activation of IL-1β/ROS and NF-κB signaling of cytokine gene expression for T. cruzi control in human and mouse macrophages. However, NLRP3-mediated IL-1β/NFκB activation is dispensable and compensated for by ROS-mediated control of T. cruzi replication and survival in macrophages.
在本研究中,我们利用野生型(WT)、ASC基因敲除(ASC-/-)和NLRP3基因敲除(NLRP3-/-)巨噬细胞以及抑制方法,来研究炎性小体激活的机制及其在克氏锥虫感染中的作用。我们还检测了人类巨噬细胞,并分析了已发表的来自人类成纤维细胞、内皮细胞和平滑肌细胞的微阵列数据集,以了解克氏锥虫诱导的RT Profiler人类炎性小体阵列中所包含的基因表达变化。与用脂多糖(LPS)处理的对照相比,克氏锥虫感染在巨噬细胞中引发了炎性小体相关基因表达和白细胞介素-1β(IL-1β)产生的减弱和延迟激活。当用半胱天冬酶-1、IL-1β或烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶抑制剂处理WT和ASC-/-巨噬细胞时,我们发现半胱天冬酶-1/ASC炎性小体产生IL-1β需要活性氧(ROS)作为二级信号。此外,IL-1β调节炎性细胞因子基因表达的核因子κB(NF-κB)信号传导,进而调节巨噬细胞内的寄生虫复制。NLRP3-/-巨噬细胞尽管无法引发IL-1β激活和炎性细胞因子基因表达,但与匹配的WT对照相比,其细胞内寄生虫数量下降了4倍。NLRP3-/-巨噬细胞对克氏锥虫并非难治性,相反,其表现出非常高的基础ROS水平(比WT对照高100倍以上),在感染后以不依赖IL-1β的方式维持,并有助于有效杀灭寄生虫。我们得出结论,半胱天冬酶-1/ASC炎性小体在激活IL-1β/ROS和NF-κB信号传导以控制人类和小鼠巨噬细胞中的克氏锥虫方面发挥着重要作用。然而,NLRP3介导的IL-1β/NFκB激活是可有可无的,并且由ROS介导的对巨噬细胞中克氏锥虫复制和存活的控制所补偿。