LncRNA PlncRNA-1 participates in rheumatoid arthritis by regulating transforming growth factor β1.

LncRNA PlncRNA-1(PlncRNA-1) participates in breast cancer by upregulating TGF-β1. It is known that TGF-β1 plays an inhibitory role in the inflammatory responses in rheumatoid arthritis (RA). Therefore, PlncRNA-1 may also participate in RA. Serum and synovial fibroblasts were obtained from 34 patients with active RA (persistent symptoms), 36 patients with inactive RA (long term of no or few symptoms after active RA) and 40 healthy controls. Expression levels of PlncRNA-1 and TGF-β1 in active RA patients, inactive RA patients and healthy controls were measured by RT-qPCR and ELISA, respectively. Pearson Correlation Coefficient was used to determine the correlation between the expression levels of PlncRNA-1 and TGF-β1. Diagnostic value of PlncRNA-1 for active RA was detected by ROC curve analysis. PlncRNA-1 and TGF-β1 were downregulated in serum of active RA patients but not in inactive RA patients compared to the healthy controls. Expression of PlncRNA-1 and TGF-β1 were positively correlated only in RA patients, and altered expression levels of PlncRNA-1 distinguished the active RA patients from inactive RA patients and healthy controls. PlncRNA-1 and TGF-β1 were also downregulated in synovial fibroblasts derived from RA patients in comparison to inactive RA patients and healthy controls. Overexpression of PlncRNA-1 mediated upregulation of TGF-β1 in synovial fibroblasts derived from RA patients, while exogenous TGF-β1 treatment showed no significant effect on the expression of PlncRNA-1. Therefore, PlncRNA-1 participated in RA possibly by regulating TGF-β1.