MicroRNA‑502‑3p promotes Mycobacteriumtuberculosis survival in macrophages by modulating the inflammatory response by targeting ROCK1.

Abstract

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tuberculosis) infection and has the highest mortality rate of any single infectious disease worldwide. The aim of the present study was to investigate the function of microRNA (miR)-502-3p in M. tuberculosis-infected macrophages. The Gene Expression Omnibus database was used to analyze miR-502-3p expression in patients with TB and healthy individuals. THP-1 and RAW 264.7 cells were transfected with miR-502-3p mimic, miR-502-3p inhibitor, pcDNA3.1-ROCK1 or their negative controls. The expression levels of miR-502-3p and inflammatory cytokines were evaluated using reverse transcription-quantitative PCR. The colony-forming unit assay was performed to assess the survival of M. tuberculosis in macrophages, and Toll-like receptor (TLR)4/NF-κB signaling pathway-associated protein expression levels were detected by western blotting. The nuclear translocation of NF-κB p65 was detected via immunocytochemistry. TargetScan was used to predict the binding sites between miR-502-3p and ROCK1. The interaction between miR-502-3p and Rho-associated coiled-coil-forming protein kinase 1 (ROCK1) was confirmed using a dual-luciferase reporter assay; ROCK1 was demonstrated to be a direct target gene of miR-502-3p. Results from the present study demonstrated that miR-502-3p expression was significantly increased during M. tuberculosis infection in macrophages. Upregulation of miR-502-3p expression levels significantly enhanced the survival of intracellular M. tuberculosis. IL-6, TNF-α, and IL-1β mRNA expression levels were significantly upregulated during M. tuberculosis infection but were downregulated by miR-502-3p overexpression. Moreover, miR-502-3p mimics transfection significantly downregulated TLR4/NF-κB signaling pathway-associated protein expression and significantly reduced nuclear transcription of NF-κB in M. tuberculosis-infected macrophages. ROCK1 overexpression reversed the miR-502-3p inhibitory effect on cytokine production in M. tuberculosis-infected macrophages. In conclusion, miR-502-3p/ROCK1 may serve an anti-inflammatory role and may improve the survival of M. tuberculosis within macrophages, which may provide a promising therapeutic target for TB.