FRI0262 Differences in serum microrna profile in active systemic lupus erythematosus and healthy controls

Background The microRNAs (miRNA) are small, non-coding RNA with a role in regulation of gene expression at post-transcriptional level and some of them are suggested to be involved in the adaptive and innate immunity regulation. MiRNA have been identified not only intracellularly, but in body fluid as well. Some of the serum miRNA serve as biomarkers of various diseases particularly autoimmune like systemic lupus erythematosus (SLE). Objectives The aim of our work was to identify differences in serum miRNA profile in SLE patients and healthy individuals. Methods Altogether, 11 patients suffering from active SLE without active lupus nephritis (average SLEDAI: 14,63, average age 41,36 years) and 16 healthy individuals (average age 39,81 years) as control group were investigated. Serum miRNA was isolated from serum by trisol-acid phenol precipitation. The expression of 1347 to date known miRNA was tested using microarray analysis. Paired comparisons between experimental groups were performed by the nonparametric Mann-Whitney U test. Pearson’s and Spearman’s correlation coefficients were calculated to determine the correlation between miRNA expression levels of two genes. The statistical analyses were performed using WinSTAT® software. Results Total 106 miRNA of all tested miRNA show significant differences in expression between SLE patients and healthy controls. Only 8 miRNA show significantly decreased expression in SLE whereas 98 of all miRNA were upregulated in SLE. Interestingly, only in a part of the identified SLE - associated miRNA have been known their immunological functions, the other miRNA have a role in apoptosis, cell proliferations, drug resistance or their function have not been identified yet. Conclusions Our work demonstrated the differences between serum miRNA profile in active SLE patients and healthy controls. The serum miRNA profile is different than miRNA profile of peripheral mononuclear cells and may reflect the intercellular communication. This pilot study identifies potential SLE - associated miRNA, which are connected to higher risk of active SLE with severe organ manifestation. The next step of our work is to quantify potential risk miRNA and establish some serum miRNA as biomarker of active SLE. References Wang G, et al. Serum and urinary free microRNA levels in patients with systemic lupus erythematosus. Lupus 2011, 20: 493-500. Shen N, et al. MicroRNAs – novel regulators of systemic lupus erythematosus pathogenesis. Nat Rev Rheum