The Study of m6A, m5C, m1A, m7G, Adenosine-to-Inosine and Pseudouridine RNA Modification-related Molecules in Peripheral Blood of Rheumatoid Arthritis

Background The overall situation of RNA epigenetics in rheumatoid arthritis (RA) is still unclear. This study aims to investigate the expression level of m6A, m5C, m1A, m7G, adenosine-to-inosine, pseudouridine(ψ) modification-related molecules in peripheral blood of RA. Methods 33 RA patients and 36 healthy donors (HD) were included in this study. Gene expression levels were detected by real time-polymerase chain reaction (RT-PCR). Correlation analyses were performed by Pearson correlation test. Least absolute shrinkage and selection operator regression (LASSO) regression and Logistic regression were used for seeking risk factors. Results The expression levels of METTL3, TET2, ADAR1 increased while ALKBH5, TRMT10C TRMT61B ALKBH3 ALYREF METTL1 decreased in RA patients. Analysis shown 47 weak correlations, 43 moderate correlations and 2 strong correlations existed among these molecules. Area under curve (AUC) of ALYREF and TET2 combined ROC was 0.976 which indicated them were the most valuable risk factors in RA. The expression of ALKBH3 and TRMT10C was higher in ESR-negative RA patients, while the expression of METTL1 and METTL3 was higher in RF-negative group or CRP-negative group respectively. Besides, the level of METTL3 and TRMT10C was increased in DAS-28-ESR. Furthermore, METTL3 level was negative related with the levels of RF and DAS28-ESR. The level of TRMT10C was negative with ESR and DAS-28-ESR levels, and ALKBH5 expression was positive related with CRP level. The differential expression genes were mostly correlated with PLT and MCHC of blood routine examination. Conclusions Our study constructed a network of six kinds of mRNA modifications in RA. We found multiple mRNA-modification-related genes were different expression between RA patients and HD. Complicated mutual relations existed among these genes. ALYREF and TET2 were the most valuable risk factors in RA. This work hopes to support a new perspective for clarifying pathogenic mechanism of RA.