Increased expression of long noncoding RNAs LOC100652951 and LOC100506036 in T cells from patients with rheumatoid arthritis facilitates the inflammatory responses.

The aim of this study was to evaluate whether the presence of aberrantly expressed lncRNAs could promote T cell inflammatory responses in patients with RA. The expression levels of 10 potential aberrantly expressed lncRNAs were evaluated in T cells from 39 patients with RA and 17 controls using real-time reverse transcription polymerase chain reaction. The aberrantly expressed lncRNAs were measured in Jurkat cells co-cultured with or without ionomycin and phorbol 12-myristate 13-acetate. Transfection studies using small interfering RNA (siRNA) were conducted for biological functions, and microarray analysis was performed to search for target genes of specific lncRNAs. We confirmed that the expression levels of LOC100652951 and LOC100506036 were higher in RA T cells compared with controls. RA patients treated with biologic agents had lower expression levels of LOC100652951, and female RA patients had lower LOC100506036 expression levels after multivariate analysis. After activation, the expression levels of LOC100506036, but not LOC100652951, increased in Jurkat cells. Transfection of siRNA targeting LOC100506036 inhibited interferon gamma production and the expression of nuclear factor of activated T cells in activated Jurkat cells. After the microarray analysis with validation, inhibition of LOC100506036 expression by siRNA leaded to the decreased expression of sphingomyelin phosphodiesterase 1 (SMPD1). In conclusion, the expression levels of LOC100652951 and LOC100506036 were increased in RA T cells. Treatment with biologic agents could lower the expression of LOC100652951 in RA T cells. LOC100506036 could regulate the expression of SMPD1 and NFAT1 and could contribute to the inflammatory responses in RA.