BACKGROUND: The pathological features of rheumatoid arthritis (RA) include synovial pannus and inflammatory responses, which in turn lead to joint destruction.Neovascularization has a significant impact on synovia vascular opacification formation, while RA fibroblast-like synoviocytes (RA-FLS) are pivotal in synovial proliferation and joint degradation. Long-stranded noncoding RNAs (LncRNAs) are crucial regulators across various diseases, but their role in RA remains incompletely understood. In the present investigation, we examined the involvement of LncRNA EBLN3P in RA synovial angiogenesis via modulation of the JAK/STAT signaling pathway, mediated by the miR-369-3p/NFIX axis.LncRNAs serve as crucial regulators in a wide range of diseases, but the precise mechanisms underlying their involvement in RA remain incompletely elucidated. This study reveals the potential mechanism of LncRNA EBLN3P in RA synovial angiogenesis through miR-369-3p/NFIX molecular axis-mediated modulates the JAK/STAT signaling pathway. METHODS: The interplay among LncRNA EBLN3P, miR-369-3p, and NFIX was confirmed via a dual-luciferase reporter assay.Through qRT-PCR, Western blotting, EdU proliferation detection, scratch migration assay, Transwell invasion assay and ELISA technology, modulating RA-FLS proliferation, migration, invasion, angiogenesis-related factor secretion, matrix degradation activity, and JAK/STAT signaling pathway activation by LncRNA EBLN3P was systematically resolved. Role. In the current study, we further combined in vitro lumen formation assay and immunofluorescence staining technique to investigate the effects of lncRNA EBLN3P on RA-FLS-induced HUVEC angiogenic capacity and endothelial marker expression. RESULTS: LncRNA EBLN3P overexpression promotes angiogenic function by regulating the biological behavior (proliferation, migration, invasion) and the levels of angiogenic factors of RA-FLS, forming a pro-angiogenic microenvironment, which in turn promotes angiogenic function, as well as RA-FLS-induced enhancement of the tube-forming capacity and endothelial marker CD34 in HUVEC, CD105 expression was upregulated. In addition, LncRNA EBLN3P overexpression activated the JAK/STAT signaling pathway by suppressing miR-369-3p expression and upregulating NFIX expression, which in turn activated the JAK/STAT signaling pathway. In contrast, knockdown of the LncRNA EBLN3P significantly suppressed these effects. CONCLUSION:LncRNA EBLN3P stimulates the JAK/STAT signaling pathway via the miR-369-3p/NFIX axis, thereby enhancing synovial neovascularization in RA

Abstract: Background: The abnormal expression of lncRNA HOTAIR has been associated with synovial angiogenesis in rheumatoid arthritis (RA). The aim of this study is to investigate whether lncRNA HOTAIR can participate in synovial angiogenesis in RA by regulating the PI3K/AKT pathway through the miR-126/PIK3R2 axis. Methods: In this study, we conducted in vitro experiments by designing overexpression plasmids and small interfering RNAs targeting lncRNA HOTAIR and then transfected them into fibroblast-like synoviocytes (FLS) obtained from RA patients. We then co-cultured the modified FLS with human umbilical vein endothelial cells (HUVEC) to establish an RA-FLS-induced HUVEC model. We investigated the effects of lncRNA HOTAIR on the proliferation, migration, and tube formation abilities of HUVECs, as well as the expression of synovial endothelial cell markers, angiogenic factors, and the PI3K/AKT pathway. To validate the interactions between lncRNA HOTAIR, miR-126-3p, and PIK3R2, we used bioinformatics and luciferase reporter experiments. We also used a combination of real-time fluorescence quantitative (RT-qPCR), Western blotting (WB), and immunofluorescence (IF) methods to identify target genes and proteins. Results: LncRNA HOTAIR was highly expressed in HUVEC cells induced by RA-FLS. Overexpression of lncRNA HOTAIR significantly increased the expression of VEGF, bFGF, CD34 and CD105 in HUVEC cells, promoted their proliferation, invasion, and tube formation, while the silencing of lncRNA HOTAIR reversed these effects, and the PI3K/AKT activator also reversed them. Overexpression of lncRNA HOTAIR activated the PI3K/AKT pathway, promoting the expression of PI3K, AKT, and P-AKT proteins. Bioinformatics and dual-luciferase assays verified the targeting relationship between LncRNA HOTAIR, miR-126-3p, and PIK3R2. Conclusion: LncRNA HOTAIR can activate the PI3K/AKT pathway, possibly through the regulatory axis of miR-126-3p/PIK3R2, and thus participate in synovial angiogenesis in rheumatoid arthritis.