Long non-coding RNA (lncRNA) growth arrest specific transcript 5 (GAS5) negatively regulates interleukin-18 (IL-18) in ovarian cancer, while IL-18 contributes to the development of rheumatoid arthritis (RA). Therefore, GAS5 may also participate in RA.
GAS5 and IL-18 in plasma of RA patients (n = 60) and healthy controls (n = 60) were measured by RT-qPCR and ELISA, respectively. Linear regression was performed to analyze the correlations between plasma levels of IL-18 and GAS5 in both RA patients and healthy controls.
In the present study, we found that plasma GAS5 was downregulated, while IL-18 was upregulated in RA patients than in healthy controls. A significant and inverse correlation between GAS5 and IL-18 was found in RA patients but not in healthy controls. IL-18 treatment did not significantly alter the expression of GAS5 in fibroblast-like synoviocytes, while GAS5 overexpression led to the inhibited expression of IL-18. GAS5 overexpression also resulted in the promoted apoptosis of fibroblast-like synoviocytes.
Therefore, GAS5 overexpression may improve RA by downregulating IL-18 and inducing the apoptosis of fibroblast-like synoviocytes. Key points • The present study mainly showed that overexpression of GAS5 may assist the treatment of RA. • The mechanism of GAS5 for the treatment of RA involves the downregulating inflammatory IL-18 and mediating the apoptosis of fibroblast-like synoviocytes. • GAS5 and IL-8 were correlated in RA patients but not in healthy controls.