Analysis of miRNA expression in patients with rheumatoid arthritis during remission and relapse after a 5-year trial of tofacitinib treatment.

The physiopathology of rheumatoid arthritis (RA) is mediated by proinflammatory cytokines, some of which are regulated by the JAK/STAT pathway. Tofacitinib is a JAK inhibitor, but its role in the regulation of microRNAs (miRNAs) is unknown. There is also no information regarding the role of miRNAs in the clinical relapse/remission of RA. The present project aims to identify a signature profile of miRNA expression in a subgroup of RA patients who had to discontinue tofacitinib treatment (because of the ending of a 5-year open-label clinical trial) and to describe the expression of miRNAs during RA remission or flare-up. The relative expression of 61 miRNAs was determined in serum samples with the Firefly™ BioWorks assay. Statistical analysis was performed by means of Student's t-test and heatmap analysis was performed with Firefly™ Analysis Workbench software and in the software GraphPad® Prism v5.0. Target prediction and Gene Ontology analysis were carried out using bioinformatic tools. We found a distinctive signature of miRNA expression associated with relapse, featuring upregulated expression of hsa­miR­432­5p (p < 0.05). We also found upregulation of hsa­miR­194­5p (p < 0.05) in samples of patients with RA flare-up. Gene Ontology analysis of the target genes for hsa­miR­432­5p was performed to identify relevant pathways associated with relapse; the implications of these pathways in the physiopathology of RA are discussed. Tofacitinib treatment does not have a direct effect on the expression of measured miRNAs. The changes in hsa­miR­432­5p and hsa­miR­194­5p are associated with the regulation of proinflammatory pathways and RA flare-up.

Type I Interferon Gene Response Is Increased in Early and Established Rheumatoid Arthritis and Correlates with Autoantibody Production.

BACKGROUND: Rheumatoid arthritis (RA) is an inflammatory debilitating disease that affects the joints in the early and productive phases of an individual's life. Several cytokines have been linked to the disease pathogenesis and are known to contribute to the inflammatory state characteristic of RA. The participation of type I interferon (IFN) in the pathogenesis of the disease has been already described as well as the identity of the genes that are regulated by this molecule, which are collectively known as the type I IFN signature. These genes have several functions associated with apoptosis, transcriptional regulation, protein degradation, Th2 cell induction, B cell proliferation, etc. This article evaluated the expression of several genes of the IFN signature in different stages of disease and their correlation with the levels of anticitrullinated protein antibodies (ACPA) anticarbamylated protein (Anti-CarP) antibodies. METHODS: Samples from individuals with early and established RA, high-risk individuals (ACPA+ and ACPA-), and healthy controls were recruited at "Unidad de Artritis y Rheumatismo" (Rheumatism and Arthritis Unit) in Guadalajara Jalisco Mexico. Determinations of ACPA were made with Eurodiagnostica ACPA plus kit. Anti-CarP determinations were made according to previously described protocols. RNA was isolated, and purity and integrity were determined according to RNA integrity number >6. Gene expression analysis was made by RT-qPCR using specific primers for mRNAs of the type I IFN signature. Relative gene expression was calculated according to Livak and Schmitgen. RESULTS: Significant differences in gene expression were identified when comparing the different groups for MXA and MXB (P < 0.05), also when comparing established RA and ACPA- in both IFIT 1 and G15. An increased expression of ISG15 was identified (P < 0.05), and a clear tendency toward increase was identified for HERC5. EPSTRI1, IFI6, and IFI35 were found to be elevated in the chronic/established RA and early RA (P < 0.05). Significant correlations were identified for the IFN signature genes with the levels of ACPA and anti-CarP (P < 0.05). CONCLUSION: Our data confirm previous observations in the role of IFN signature and the pathogenesis of RA. Also, we provide evidence of an association between several genes of the IFN signature (that regulate Th2 cells and B cell proliferation) with the levels of anti-CarP antibodies and ACPA.