THU0054 Long non-coding rna gaplinc promotes proliferation and invasion of fibroblast-like synoviocytes as microrna sponging in ra patients
Authors: B.Y. Mo, Y.F. Pan, X. BI, X.Q. Luo
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Accumulating evidence suggested that long non-coding RNAs (lncRNAs) play diverse functional roles in many autoimmune diseases including rheumatoid arthritis (RA). However, there is a dearth of knowledge in what role these transcripts play in fibroblast-like synoviocytes (FLSs) of RA patients. LncRNA GAPLINC, a novel long non-coding RNA, was first described in gastrointestinal cancer tissues and associated with bad behaviours of tumour cell as well as poor prognosis in patients. <h3>Objectives</h3> This study was undertaken to explore the expression and roles of LncRNA GAPLINC in RA-FLSs and investigate its possible mechanism. <h3>Methods</h3> RA-FLSs and trauma-FLSs were cultured from synovial specimens. The expression of RNA was detected by qRT-PCR. GAPLINC suppression was transfected by siRNA. Cell viability analysis was taken by CCK-8 assay and flow cytometry. Cell invasion was using transwell chamber methodology. The bioinformatics analysis was performed using miRanda, PITA, RNAhybrid algorithms, as well as KEGG and Gene Ontology(GO) analysis. <h3>Results</h3> The relative expression of LncRNA GAPLINC was significantly higher in RA-FLSs than trauma-FLSs (p<i>&lt;0.05</i>). Transfection of GAPLINC-siRNA significantly decreased the expression of LncRNA GAPLINC in RA-FLSs. GAPLINC suppression in RA-FLSs revealed significant alterations in cell proliferation and invasion. In the GAPLINC-siRNA group, a inhibition rate in growth was first observed (15.29%±0.38%) at 24 hour after transfection, then a significant suppression was observed (28.75%±2.34%) at 48 hour, more apparent (36.63%±7.93%) at 72 hour and largely maintained (35.97%±3.67%) at 96 hour after siRNA treatment, compared to the negative control group(NC-siRNA). Moreover, flow cytometry assay showed GAPIINC-siRNA group had an accumulation of cells in the G0/G1 phase and the decreased number of RA-FLSs in the S and G2/M phase. In the invasive assay, the membrane-invading RA-FLSs numbers decreased significantly in the treatment group with GAPLINC knockdown (45.0±3.0) compared to values observed in the NC-siRNA group (149.0±7.0). Above comparisons were all statistically significant (p<i>&lt;0.05)</i>. The bioinformatics analysis predicted that some of microRNAs and mRNA may be the downstream molecules of LncRNA GAPLINC, we thus simulated a gene co-action network model based on the competitive endogenous RNA (ceRNA) hypothesis. Further verification of this model demonstrated that silencing of GAPLINC increased miR-382–5 p and miR-575 expression. <h3>Conclusions</h3> The results suggest that elevated LncRNA GAPLINC expression promote the proliferation and invasion of RA-FLSs and it may function as a novel microRNAs sponging agent. Additionally, LncRNA GAPLINC may regulate RA-FLS pathological behaviours in an miR-382–5 p-dependent and miR-575-dependent manner. Based upon these findings, lncRNA GAPLINC may provide a novel valuable therapeutic target for RA patients. <h3>Acknowledgements</h3> This work was supported by grants from Province Natural Science Fund of Guangdong, China<sup>No.2014</sup>A030313080) and National Natural Science Foundation of China (No.81771750). <h3>Disclosure of Interest</h3> None declared