Luo Hou-Long, Pi Jiang, Zhang Jun-Ai, Yang En-Zhuo, Xu Huan, Luo Hong, Shen Ling, Peng Ying, Liu Gan-Bin, Song Cai-Mei, Li Ke-Yue, Wu Xian-Jin, Zheng Bi-Ying, Shen Hong-Bo, Chen Zheng W, Xu Jun-Fa
Department of Clinical Immunology Institute of Laboratory Medicine Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics Guangdong Medical University Dongguan China.
Department of Microbiology and Immunology Center for Primate Biomedical Research University of Illinois College of Medicine Chicago IL USA.
Clin Transl Immunology. 2021 Feb 18;10(2):e1254. doi: 10.1002/cti2.1254. eCollection 2021.
Genetic and epigenetic mechanisms regulate antimicrobial immunity against (Mtb) infection.
The present study assessed circular RNA TRAPPC6B (circTRAPPC6B) for antimicrobial immune functions and defined mechanisms wherein circTRAPPC6B regulates Mtb growth, autophagy and microRNA in macrophages.
The Mtb infection of monocytes/macrophages resulted in a significantly decreased level of circTRAPPC6B that inhibited intracellular Mtb growth in macrophages. Conversely, circTRAPPC6B expression enhanced autophagy or autophagy-associated protein LC3-II production in Mtb-infected macrophages. circTRAPPC6B-enhanced autophagy aggregation or sequestration was also observed in fluorescence hybridisation (FISH) analysis and confocal imaging. Mechanistically, circTRAPPC6B targets an inhibiting element miR-874-3p, as shown by bioinformatics, dual-luciferase reporter gene analysis and pull-down assay, respectively. Notably, miR-874-3p prohibited autophagy via suppressing autophagy protein ATG16L1 by binding to its 3'-untranslated region (UTR) in Mtb-infected macrophages and thus promoting intracellular Mtb growth. Concurrently, circTRAPPC6B enhanced autophagy in Mtb-infected macrophages by blocking the ability of miR-874-3p to inhibit ATG16L1. Thus, circTRAPPC6B antagonises the ability of to suppress expression and activate and enhance autophagy sequestration to restrict Mtb growth in macrophages.
The current findings suggested that both circTRAPPC6B and miR-874-3p mechanisms can be explored as potential therapeutics against Mtb infection.
遗传和表观遗传机制调节针对结核分枝杆菌（Mtb）感染的抗菌免疫。
本研究评估了环状RNA TRAPPC6B（circTRAPPC6B）的抗菌免疫功能，并确定了circTRAPPC6B调节巨噬细胞中Mtb生长、自噬和微小RNA的机制。
单核细胞/巨噬细胞的Mtb感染导致circTRAPPC6B水平显著降低，circTRAPPC6B可抑制巨噬细胞内的Mtb生长。相反，circTRAPPC6B表达增强了Mtb感染巨噬细胞中的自噬或自噬相关蛋白LC3-II的产生。在荧光原位杂交（FISH）分析和共聚焦成像中也观察到circTRAPPC6B增强的自噬聚集或隔离。从机制上讲，circTRAPPC6B靶向抑制元件miR-874-3p，分别通过生物信息学、双荧光素酶报告基因分析和下拉试验得到证实。值得注意的是，miR-874-3p通过在Mtb感染的巨噬细胞中与其3'-非翻译区（UTR）结合来抑制自噬蛋白ATG16L1，从而抑制自噬并促进细胞内Mtb生长。同时，circTRAPPC6B通过阻断miR-874-3p抑制ATG16L1的能力来增强Mtb感染巨噬细胞中的自噬。因此，circTRAPPC6B拮抗了miR-874-3p抑制ATG16L1表达并激活和增强自噬隔离以限制巨噬细胞中Mtb生长的能力。
目前的研究结果表明，circTRAPPC6B和miR-874-3p机制都可作为抗Mtb感染的潜在治疗方法进行探索。
