Erythropoiesis signature and ubiquitin-mediated proteolysis are enriched in systematic juvenile idiopathic arthritis.

Systemic Juvenile Idiopathic Arthritis (sJIA) is a distinctive subtype of Juvenile Idiopathic Arthritis (JIA). The pathogenesis of sJIA is still unclear with the limited treatment options. Although previous bioinformatics analyses have identified some genetic factors underlying sJIA, these studies were mostly single centre with a small sample size and the results were often inconsistent. Herein, we combined two data sets of GSE20307 and GSE21521 and select the matrix of patients diagnosed as sJIA in it for further analysis. The GSE20307 and GSE21521 matrixes downloaded from the Gene Expression Omnibus (GEO) were analysed using online tools GEO2R, Venny, Metascape, STRING and Cytoscape to identify differentially expressed genes (DEGs), enrichment pathways, protein-protein interaction (PPI), main module and hub genes between sJIA individuals and healthy controls. A total of 289 overlapping genes (consisting of 41 downregulated genes and 248 upregulated genes) were identified. Hub genes were primarily related to erythropoiesis. And the KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis of overlapping DEGs were mainly involved in malaria and non-small cell lung cancer. Besides, DEGs in main module were involved in ubiquitin-mediated proteolysis. Our study suggests that the erythropoiesis signature indeed exists in sJIA similar to previous reports. And ubiquitin-mediated proteolysis is important in sJIA.