Proteomic Analysis for Identification of Novel Urinary Biomarkers in Juvenile Systemic Lupus Erythematosus

Abstract Background: To identify new markers of juvenile systemic lupus erythematosus (JSLE) that facilitate patient stratification and prognosis is quite important. Therefore, our aim of the present study is to analyze alteration of protein expression and potential valuable biomarkers in juvenile systemic lupus erythematosus (JSLE) urine. Methods: Based on this aim, proteomics assay analyzed the changes of urinary proteins in study groups consisting of 9 healthy controls, 9 inactive JSLE and 10 active JSLE patients. And the correlationship between clinical characteristics of JSLE patients and new biomarkers discovered from proteomics assay was qualified.Results: We have identified a group of 105 differentially expressed proteins with ≥1.3 fold up-regulation or ≤0.77 fold down-regulation in JSLE patients. In gene ontology and functional enrichment analysis, we discovered these proteins were involved in several important biological processes such as acute phase inflammatory responses, complement activation, hemostasis, and immune system regulation. Interestingly, we found that Ephrin type-A receptor 4 (EPHA4) and Vitronectin (VTN) were significantly reduced in the urine of both inactive and active JSLE patients. Especially, the urinary VTN was also linear correlated with clinical characteristics of JSLE. Conclusion: In summary, this study provided a reliable proteomic reference profile for JSLE. Patients with active and inactive JSLE have differentially obvious metabolic proteins in the urine. VTN could be a specific diagnostic biomarker to distinguish inactive and active JSLE. These identified proteins as new biomarkers in this study can warrant some further exploiting in a larger prospective validation study.