Li Liu

LncRNA NR_003508 has been implicated in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome. Yet, the involvement of LncRNA NR_003508 in Pseudomonas aeruginosa (PA)-induced autophagy remains elusive. This study aims to reveal the underlying mechanisms of LncRNA NR_003508 in PA-induced autophagy, thereby enhancing the basic research content of the pathogenesis of PA infection. Fluorescence in situ hybridization (FISH) probes and q-PCR revealed that PA infection induced macrophage autophagy accompanied by increasing LncRNA NR_003508, suggesting that LncRNA NR_003508 may participate in competing endogenous RNA (ceRNA)-mediated regulatory networks. Concurrently, autophagic clearance of PA requires LncRNA NR_003508. Then, we used the Gene Expression Omnibus (GEO) database to find that LC3 was considered a core protein in PA-infected autophagy. Furthermore, LncRNA NR_003508 promoted the formation of autophagosomes, which played a positive role in PA clearance. Functionally, bioinformatics analysis and luciferase reporter assays demonstrated that LncRNA NR_003508 promotes the conversion of LC3I to LC3II by sponging miR-344i and facilitates p62 degradation by binding to miR-344g-5p. Taken together, our data established that LncRNA NR_003508 enhanced the formation of autophagosomes induced by PA infection via the miR-344i/LC3 and miR-344g-5p/p62 axes, partly boosting the clearance of PA and providing a theoretical basis and experimental support for understanding the mechanisms underlying PA infection.

Emerging evidence suggests that long non-coding RNAs (LncRNAs) are involved in Mtb-induced programmed necrosis. Among these LncRNAs, LncRNA NR_003508 is associated with LPS-induced acute respiratory distress syndrome. However, whether LncRNA NR_003508 contributes to Mtb-induced programmed necrosis remains undocumented. Firstly, the expression of LncRNA NR_003508 was determined using RT-qPCR and FISH. The protein expression of RIPK1, p-RIPK1, RIPK3, p-RIPK3, MLKL, and p-MLKL was measured by Western blot in RAW264.7 and mouse lung tissues. Furthermore, luciferase reporter assays and bioinformatics were used to predict specific miRNA (miR-346-3p) and mRNA (RIPK1) regulated by LncRNA NR_003508. In addition, RT-qPCR was used to detect the RIPK1 expression in TB patients and healthy peripheral blood. The flow cytometry assay was performed to detect cell necrosis rates. Here we show that BCG infection-induced cell necrosis and increased LncRNA NR_003508 expression. si-NR_003508 inhibited BCG/H37Rv-induced programmed necrosis in vitro or in vivo. Functionally, LncRNA NR_003508 has been verified as a ceRNA for absorbing miR-346-3p, which targets RIPK1. Moreover, RIPK1 expression was elevated in the peripheral blood of TB patients compared with healthy people. Knockdown of LncRNA NR_003508 or miR-346-3p overexpression suppresses cell necrosis rate and ROS accumulation in RAW264.7 cells. In conclusion, LncRNA NR_003508 functions as a positive regulator of Mtb-induced programmed necrosis via sponging miR-346-3p to regulate RIPK1. Our findings may provide a promising therapeutic target for tuberculosis.