Expression and clinical significance of microRNA-223 and NLRP3 inflammasome in peripheral blood mononuclear cells in patients with systemic lupus erythematosus

Objective To determine the mRNA levels of microRNA-223 (miR-223) and NLRP3 in-flammasome components [Nod-like receptor pyrin domain-containing protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1] in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) and to explore its clinical significance. Methods Real time polymerase chain reaction (PCR) was used to detect the mRNAlevels of miR-223 and NLRP3 inflam-masome components in PBMCs from 35 SLE patients, 30 healthy controls and 20 SLE patients after treatment, and then their correlations with clinical and laboratory parameters [anti-double-stranded deoxyribon-ucleic acid (dsDNA) antibody, anti-nucleosome antibody (AnuA), erythrocyte sedi-mentation rate (ESR)] were evaluated. Data were analyzed using t test or χ2 test and Pearson test was used for correlation analysis. Results Com-pared with healthy controls, mRNA levels of miR-223 and Caspase-1 were higher in the PBMCs from SLE patients [(1.17±0.15) vs (0.68±0.14), t=2.416, P=0.018 6; (1.89±0.13) vs (1.32±0.13), t=3.123, P=0.002 7], but the NLRP3 and ASC mRNA expression levels were in the opposite [(0.64±0.05) vs (0.98±0.06), t=4.442, P<0.01; (0.98±0.08) vs (1.32±0.12), t=2.391, P=0.019 8]. Correlation analysis results showed that there was a negative correlation of mRNA levels between the miR-223 and NLRP3 (r=-0.784 9, P<0.05), but the miR-223 had no correlation with ASC and caspase-1. The mRNA levels of miR-223 was positively correlated with anti-dsDNA antibody, SLEDAI and ESR (r=0.703 5, 0.692 3, 0.687 3, all P values<0.05), but had no correlation with AnuA. After treatment, the mRNA expression of miR-223 and caspase-1 in PBMCs from SLE patients was significantly reduced [(1.30±0.22) vs (0.79±0.11), t=2.07, P=0.045 3; (2.05±0.19) vs (1.50±0.11), t=2.471, P=0.018 3], while the mRNA level of NLRP3 increased [(0.69±0.08) vs (0.94±0.07); t=2.445, P=0.019 3]. There was no significant difference in the expression of miR-223 mRNA in PBMCs between lupus nephritis (LN) patients and SLE patients without renal impairment. Conclusion miR-223 and caspase-1 are highly ex-pressed in the PBMCs from patients with SLE, while the mRNA of NLRP3 and ASC is in low expression. The mRNA expression of miR-223 is negatively correlated with NLRP3 and disease activity. Expression of miR-223 mRNA decreases significantly after treatment. So miR-223 may play an important role in the pathogenesis of SLE. Key words: Lupus erythematosus, systemic; MicroRNA-223; Nod-like receptor pyrin domaincontaining protein 3; Inflammasome