Long non-coding RNA-XLOC_002383 enhances the inhibitory effects of THP-1 macrophages on Mycobacterium avium and functions as a competing endogenous RNA by sponging miR-146a-5p to target TRAF6

Abstract

The morbidity associated with infection by Mycobacterium avium (M. avium), a type of non-tuberculous mycobacteria (NTM), has increased in recent years due to infections that are easily missed, and thus, difficult to diagnose and treat. Here, we reported that miR-146a-5p was highly expressed, and XLOC_002383 and TRAF6 were downregulated in a time- and MOI-dependent manner in THP-1 macrophages infected with M. avium. In macrophages obtained from peripheral blood mononuclear cells, the expression levels of XLOC_002383 and TRAF6 were also decreased, and miR-146a-5p expression was increased following 24 h of infection with M. avium. miR-146a-5p was a target of XLOC_002383 and TRAF6 mRNA was a target of miR-146a-5p, and XLOC_002383 regulated TRAF6 expression by adsorbing miR-146a-5p, and further increased IL-6, TNF-α, IL-1β and iNOS levels in THP-1 macrophages. The results of qPCR and CFU assays indicated that XLOC_002383 decreased the intracellular M. avium loads. Overall, the present study demonstrated that XLOC_002383 may function as a competing endogenous RNA and interacts with miR-146a-5p to increase THP-1 macrophage inflammatory factors and microbicidal mediators iNOS. This enhanced the inhibitory effects of THP-1 macrophages on M. avium, which improved the understanding of the pathogenesis and host defenses in the process of NTM infectious diseases.

Keywords: Inflammatory factor; Inhibitory ability; M. avium; Microbicidal mediator; lncRNA-XLOC_002383; miR-146a-5p.