Knockdown of long non-coding RNA PVT1 induces apoptosis of fibroblast-like synoviocytes through modulating miR-543-dependent SCUBE2 in rheumatoid arthritis

BACKGROUND: Rheumatoid arthritis (RA), a kind of autoimmune disorder, is featured by many physical symptoms and proliferation of fibroblast-like synoviocytes (FLSs). The relevance of long non-coding RNAs (lncRNAs) in the progression of RA has been probed. Hence, the goal of this report was to investigate the action of plasmacytoma variant translocation 1 (PVT1), a lncRNA, in FLSs and the basic mechanism. METHODS: Initially, RA rats were developed to evaluate the expression of PVT1, microRNA-543 (miR-543), and signal peptide-CUB-EGF-like containing protein 2 (SCUBE2) in synovial tissues. Enhancement or loss of PVT1 or miR-543 was achieved to explore their effects on proliferation, cell cycle, and apoptosis of FLSs. The interaction between PVT1 and miR-543 and between miR-543 and its putative target SCUBE2 was examined to elucidate the correlations. Finally, the protein expression of proliferation- and apoptosis-associated genes were assessed by western blot assays. RESULTS: PVT1 was overexpressed in synovial tissues from RA patients through microarray expression profiles. The PVT1 and SCUBE2 expression was boosted, and miR-543 was reduced in synovial tissues of rats with RA. PVT1 specifically bound to miR-543, and miR-543 negatively regulated SCUBE2 expression. Overexpression of PVT1 or silencing of miR-543 enhanced SCUBE2 expression, thereby promoting proliferation and interleukin-1β (IL-1β) secretion, while inhibiting apoptosis rate of FLSs. Conversely, si-SCUBE2 reversed the role of miR-543 inhibitor. CONCLUSION: The key findings support that PVT1 knockdown has the potency to hinder RA progression by inhibiting SCUBE2 expression to sponge miR-543.