Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China.
Front Immunol. 2022 Mar 9;13:827004. doi: 10.3389/fimmu.2022.827004. eCollection 2022.
is an intracellular protozoan that mainly infects cattle to cause abortion and significant economic losses worldwide. A better understanding of the immune evasion mechanisms of could help to search for an effective approach to prevent and treat neosporosis. Mitophagy is used by some viruses to evade host immune surveillance. However, host cell mitophagy and its effect on infection is unclear. In the present study, -induced host cell mitophagy and its role in parasite infection were investigated and . Furthermore, the regulation of -induced host cell mitophagy on the production of Reactive Oxygen Species (ROS), the secretions of proinflammatory cytokines, and the signals of p38, ERK, and Nlrp3 inflammasome were explored. Our results showed that autophagosomes and co-localization of LC3 with mitochondria were observed in infected macrophages. The mtDNA/nDNA ratio and the levels of mitochondrial marker proteins (Hsp60 and Tim23) were decreased with the increase of N. caninum numbers or infection time. N. caninum could induce mitophagy in brain and peritoneal lavage fluid cells of mice. Promoting mitophagy mitophagy inducers (CCCP) could shorten survival time, decrease body weight, increase parasite load, and attenuate secretion of cytokines in infected mice. CCCP treatment decreased the production of cytokines and Reactive Oxygen Species (ROS), and increased parasite burden in -infected macrophages. Furthermore, CCCP or NAC (ROS inhibitor) treatment could inhibit ERK signal, Nlrp3 inflammasome, and cytokine production, while promote p38 signal in -infected macrophages. The opposite results were obtained when using a mitophagy inhibitor (Mdivi1). Taken together, -induced mitophagy could regulate the activations of p38, ERK, Nlrp3 inflammasome to inhibit the production of inflammatory cytokines in a ROS-dependent manner to escape host immune surveillance.
弓形虫是一种细胞内原生动物,主要感染牛,导致流产和全球重大经济损失。更好地了解弓形虫的免疫逃避机制有助于寻找预防和治疗新孢子虫病的有效方法。一些病毒利用细胞自噬来逃避宿主免疫监视。然而,宿主细胞自噬及其对弓形虫感染的影响尚不清楚。本研究旨在探讨弓形虫诱导的宿主细胞自噬及其在寄生虫感染中的作用。此外,还探讨了弓形虫诱导的宿主细胞自噬对活性氧(ROS)产生、促炎细胞因子分泌以及 p38、ERK 和 Nlrp3 炎性小体信号的调节作用。结果显示,感染巨噬细胞中观察到自噬体和 LC3 与线粒体的共定位。随着弓形虫数量或感染时间的增加,mtDNA/nDNA 比值和线粒体标记蛋白(Hsp60 和 Tim23)水平降低。弓形虫可诱导小鼠脑和腹腔灌洗液细胞发生自噬。促进自噬(CCCP)可缩短感染小鼠的存活时间、降低体重、增加寄生虫负荷、并减弱感染弓形虫小鼠细胞因子的分泌。CCCP 处理降低了细胞因子和活性氧(ROS)的产生,并增加了感染弓形虫的巨噬细胞中的寄生虫负荷。此外,CCCP 或 NAC(ROS 抑制剂)处理可抑制感染弓形虫的巨噬细胞中 ERK 信号、Nlrp3 炎性小体和细胞因子的产生,而促进 p38 信号。使用自噬抑制剂(Mdivi1)则可获得相反的结果。综上所述,弓形虫诱导的自噬可能通过 ROS 依赖性调节 p38、ERK、Nlrp3 炎性小体的激活来抑制炎症细胞因子的产生,从而逃避宿主免疫监视。