A microRNA sponge, LINC02193, promotes neutrophil activation by upregulating ICAM1 and is correlated with ANCA-associated vasculitis.

Objective: To investigate the pathogenic role and underlying mechanisms of long noncoding RNAs (lncRNAs) in ANCA-associated vasculitis (AAV).

Methods: RNA-sequencing (RNA-seq) was applied to screen the expression profile of lncRNAs in peripheral leukocytes from five AAV patients and five healthy controls (HC). Candidate lncRNAs were preliminarily verified in peripheral leukocytes from 46 AAV patients and 35 HC by qRT-PCR. Then, the identified LINC02193 was further validated in peripheral neutrophils from 67 AAV patients, 45 HC and 64 disease controls. Correlation between LINC02193 levels and disease activity was analysed. Then, a loss-of-function study was conducted to investigate the role of LINC02193 in neutrophils activation. Furthermore, bioinformatics analysis, dual luciferase reporter and RNA immunoprecipitation assays were performed to explore the mechanism of LINC02193 regulating neutrophils activation.

Results: A total of 467 upregulated and 412 downregulated lncRNAs were identified in AAV patients. From the top five upregulated lncRNAs, an elevation of LINC02193 was validated in a larger sample of AAV patients, and positively correlated with disease activity. Knockdown of LINC02193 inhibited reactive oxygen species and nitric oxide production, neutrophil extracellular traps release and adhesion to endothelial cells of differentiated human promyelocytic leukaemia HL-60 cells, whereas overexpression of ICAM1 counteracted these effects. Mechanistic analysis demonstrated that LINC02193 acted as an miR-485-5p sponge to relieve the repressive effect of miR-485-5p on ICAM1, thus promoting ICAM1 expression.

Conclusion: LINC02193, a novel lncRNA identified in AAV, could function as competing endogenous RNAs for miR-485-5p to promote ICAM1 expression and neutrophils activation, suggesting its potential as a therapeutic target of AAV.