Plasma circPTPN22 and its potential target microRNA-200a-3p as novel diagnostic biomarkers in systemic lupus erythematosus patients

Background: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with heterogeneous manifestations and intricate pathophysiology. Driven by its complicated diagnostic framework, an interest in innovative diagnostic approaches has been steadily growing. Circular RNAs (circRNAs) are novel class of noncoding RNAs involved in the development of various diseases including SLE. Aim of the work: To investigate circPTPN22, microRNA-200a-3p (miR-200a-3p) and interleukin-2 (IL-2) in SLE patients and study their diagnostic potential. Patients and methods: The study included 45 patients and 45 control. The expression of circPTPN22 and miR-200a-3p were evaluated using quantitative reverse transcription polymerized chain reaction PCR. In addition, plasma IL-2 levels were determined by ELISA. The SLE disease activity index (SLEDAI) was assessed. Results: The patients were 42 females and 3 males, and their mean age was 33.6 +/- 7.9 years and disease duration 11 +/- 6.5 years. The expression of circPTPN22 and IL-2 were significantly lower in patients (0.33 +/- 0.18 and 35.7 +/- 22.02 pg/ml) compared to control (1 +/- 0.1 and 147 +/- 153.3 pg/ml respectively; p < 0.001). Meanwhile, the expression of miR-200a-3p was significantly higher in patients (4.59 +/- 1.35 vs 1.11 +/- 0.35; p < 0.001). A significant negative correlation was noticeable between circPTPN22 and miR-200a-3p expression. No correlation was found between IL-2 plasma levels and either circPTPN22 or miR-200a-3p and there was no correlation with clinical manifestations or SLEDAI. circPTPN22, miR200a-3p and IL-2 could significantly differentiate patients and controls (p < 0.0001); with an area under the curve (AUC) of 0.99, 0.998 and 0.89 respectively. Conclusions: CircPTPN22 and miR-200a-3p are potential non-invasive diagnostic biomarkers for SLE, where circPTPN22 might function through sponging miR-200a-3p and interrupting its function. (C) 2021 THE AUTHORS. Publishing services by ELSEVIER B.V. on behalf of The Egyptian Society of Rheumatic Diseases.