miR-144-3p aggravated cartilage injury in rheumatoid arthritis by regulating BMP2/PI3K/Akt axis.

Objectives: Present study aimed to illustrate the role of miR-144-3p in rheumatoid arthritis (RA).

Methods: N1511 chondrocytes were stimulated by interleukin (IL)-1β to mimic RA injury model in vitro. Rats were subjected to injection of type II collagen to establish an in vivo RA model, and the arthritis index score was calculated. Cell viability was determined by Cell Counting Kit-8. The expression of cartilage extracellular matrix proteins (collagen II and aggrecan) and matrix metalloproteinase protein were determined by quantitative real-time polymerase chain reaction and western blots. Cell apoptosis was measured by flow cytometry. Enzyme-linked immunosorbent assay was applied to test the secretion of pro-inflammatory cytokines (IL-1β and tumour necrosis factor-α). Tissue injury and apoptosis were detected by haematoxylin-eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling assay staining. Interaction of miR-144-3p and bone morphogenetic protein 2 (BMP2) was verified by dual-luciferase assay.

Results: miR-144-3p was dramatically increased in IL-1β-induced N1511 cells. miR-144-3p depletion elevated cell viability, suppressed apoptosis, pro-inflammatory cytokine releasing, and extracellular matrix loss in IL-1β-induced N1511 cells. Moreover, miR-144-3p targeted BMP2 to modulate its expression negatively. Activation of phosphatidylinositol 3-kinase (PI3K)/Akt signalling compromised inhibition of BMP2 induced aggravated N1511 cell injury with IL-1β stimulation. Inhibition of miR-144-3p alleviated cartilage injury and inflammatory in RA rats.

Conclusion: Collectively, miR-144-3p could aggravate chondrocyte injury inflammatory response in RA via BMP2/PI3K/Akt axis.