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)-1ß 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-1ß 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-1ß-induced N1511 cells. miR-144-3p depletion elevated cell viability, suppressed apoptosis, pro-inflammatory cytokine releasing, and extracellular matrix loss in IL-1ß-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-1ß 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.

MiR-144-3p induced by SP1 promotes IL-1ß-induced pyroptosis in chondrocytes via PTEN/PINK1/Parkin axis.

Rheumatoid arthritis (RA) often leads to functional disabilities and deformities. MiRNA plays a vital role in cell pyroptosis. Nevertheless, the function and underlying mechanism of miR-144-3p in pyroptosis during the progression of RA remains unclear. In this study, N1511 cells were stimulated with IL-1ß to construct a RA model. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to assess the cell viability. Cell pyroptosis was detected by flow cytometry. The levels of inflammatory cytokines (TNF-α, IL-6, and IL-18) were assessed by enzyme-linked immunosorbent assay (ELISA). The relationship among specific protein 1 (SP1), microRNA-144-3p (miR-144-3p), and phosphatase and tensin homolog (PTEN) was explored by dual-luciferase reporter assay, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP), respectively. The level of miR-144-3p in N1511 cells was upregulated by IL-1ß. MiR-144-3p knockdown inhibited IL-1ß-induced pyroptosis in N1511 cells, and the expressions of NOD-like receptor family pyrin domain containing 3 (NLRP3), Cleaved caspase-1, Gasdermin D (GSDMD), and Cleaved caspase-3 in IL-1ß-stimulated N1511 cells were increased. The levels of inflammatory cytokines in N1511 cells were increased by IL-1ß, which were restored by miR-144-3p knockdown. MiR-144-3p knockdown abolished IL-1ß-induced inactivation of putative kinase 1 (PINK1)/Parkin RBR E3 ubiquitin-protein (Parkin) signalling. Moreover, transcription factor SP1 could upregulate miR-144-3p expression and miR-144-3p negatively regulated PTEN expression. In summary, MiR-144-3p induced by SP1 could promote IL-1ß-induced chondrocyte pyroptosis via inhibiting PTEN expression and suppressing the activation of PINK1/Parkin signalling, which provided a new strategy against RA.