Role of long non-coding RNA RP11-288L9.1 in systemic lupus erythematosus and underlying mechanism

Objective To investigate the role of long non-coding RNA (lncRNA) RP11-288L9.1 in systemic lupus erythematosus (SLE) and its potential mechanism. Methods Transcriptome sequencing (RNA-seq) was used to screen the differentially expressed lncRNAs in peripheral blood mononuclear cells (PBMCs) of SLE patients, and the expression levels of these lncRNAs in 8 pairs of SLE patients and healthy controls were further verified by qRT-PCR. The knockdown as well as over-expression models of RP11-288L9.1 were constructed respectively by transfecting recombinant lentivirus into macrophages, and the transfection efficiency was determined subsequently. The subcellular distribution of RP11-288L9.1 was detected by fluorescence in situ hybridization (FISH) technique. Moreover, CCK-8 assay and Annexin V-FITC apoptosis detection kit were applied to examine the proliferation and apoptosis of macrophages in both models, and qRT-PCR was conducted to detect the expression of macrophage-related inflammatory cytokines, IL-1β, IL-6, IL-4, IL-10 and TGF-β1 after the transfection. Results Six differentially expressed lncRNAs were found (P < 0.05), in which RP11-288L9.1 was significantly up-regulated (P < 0.01), and mainly located in the cytoplasm of macrophages. The over-expression of RP11-288L9.1 promoted the apoptosis and inhibited the proliferation of macrophages (P < 0.05), increasing the levels of IL-1β and IL-6, and decreasing those of IL-4, IL-10 and TGF-β1 (P < 0.01). In contrast, the knockdown of RP11-288L9.1 significantly induced the proliferation of macrophages and inhibited the apoptosis (P < 0.05), with lowered levels of IL-1β and IL-6 and elevated IL-4, IL-10 and TGF-β1 (P < 0.01). Conclusion RP11-288L9.1 is highly expressed in the PBMCs of SLE patients, and regulates immune response in macrophages by affecting the synthesis of inflammatory cytokines, which may contribute to the occurrence of SLE