Expression profile and diagnostic value of circRNAs in peripheral blood from patients with systemic lupus erythematosus

Abstract

Circular RNAs (circRNAs) have gained attention due to their performance in disease diagnosis. However, the characteristics of circRNAs in peripheral blood from patients with systemic lupus erythematosus (SLE) remain unknown. Therefore, the aim of the present study was to determine the expression profile and diagnostic potential of circRNAs in peripheral blood from patients with SLE. The global circRNA expression in the peripheral blood of patients with SLE and healthy controls (HCs) was detected using a circRNA microarray. Then, the expression levels of three upregulated circRNAs were selected for further validation by reverse transcription‑quantitative PCR (RT‑qPCR) in a training set. Moreover, the diagnostic value of these circRNAs was assessed by constructing a receiver operating characteristic curve, and then verified in a blind testing set. In total, 1,566 circRNAs were identified to be dysregulated between patients with SLE and HCs (≥2 fold change, P<0.05). Furthermore, the RT‑qPCR results were consistent with the microarray data, in that all three selected circRNAs, hsa_circ_0082688, hsa_circ_0082689 and hsa_circ_0008675, were significantly upregulated in patients with SLE (P<0.05). Results from the training set demonstrated that the combination of hsa_circ_0082688‑hsa_circ_0082689 may provide the most beneficial diagnostic potential. Moreover, the blind test results indicated that the combination model of hsa_circ_0082688‑hsa_circ_0082689 could effectively discriminate between patients with SLE from patients with rheumatoid arthritis and HCs, with a sensitivity of 91.30%, a specificity of 78.57% and an accuracy of 82.28%. Moreover, the combination model of hsa_circ_0082688‑hsa_circ_0082689 + anti‑dsDNA could more effectively discriminated the SLE group from the control groups, with a sensitivity of 95.65%, a specificity of 100.00% and an accuracy of 98.73%. In addition, correlation analysis results suggested that all three circRNAs in patients with SLE did not correlate with the SLE disease activity index. In conclusion, the expression levels of hsa_circ_0082688‑hsa_circ_0082689 may serve as potential biomarkers for SLE diagnosis.

Keywords: systemic lupus erythematosus; circular RNAs; microarray assay; peripheral blood.

Figure 1.

Microarray assay results demonstrate the circRNA expression profiles in peripheral blood from three patients with SLE and 3 HCs. (A) Box plot used to visualize the distributions of a dataset for the circRNAs profiles. (B) circRNA scatter plot. Dots above the top green line and below the bottom green line indicate >1.5-fold of changes of logarithmized circRNAs between the two groups. (C) Heat map of differentially expressed circRNAs. circRNAs, circular RNAs; HC, healthy controls; SLE, systemic lupus erythematosus.

Figure 2.

Reverse transcription-quantitative PCR results of the relative expression levels of circRNAs in peripheral blood from patients with SLE and the comparison group. (A) Average expression levels of hsa_circ_0082688 in patients with SLE were significantly increased compared with the HCs. (B) Average expression levels of hsa_circ_0082689 in patients with SLE were significantly increased compared with the HCs. (C) The average expression levels of hsa_circ_0008675 in patients with SLE were significantly increased compared with the HCs. (D) Average expression of hsa_circ_0082688 did not show any significant differences between patients with newly diagnosed or recurrent SLE. (E) Average expression of hsa_circ_0082689 did not show any significant differences between patients with newly diagnosed or recurrent SLE. (F) Average expression of hsa_circ_0008675 did not show any significant differences between patients with newly diagnosed or recurrent SLE. circRNAs, circular RNAs; HC, healthy controls; SLE, systemic lupus erythematosus.

Figure 3.

ROC analysis of identified circRNAs in peripheral blood from patients with SLE. (A) ROC curves for circRNAs, largest AUC was demonstrated for hsa_circ_0082689, followed by hsa_circ_0082688, hsa_circ_0008675. (B) ROC curves for circRNAs in combination, combined AUC from these circRNAs (hsa_circ_0082688 and hsa_circ_0082689) was 0.740. AUC, area under the curve; circRNAs, circular RNAs; ROC, receiver operating characteristic; SLE, systemic lupus erythematosus.

Figure 4.

Validation the of hsa_circ_0082688 and hsa_circ_0082689 in the blind testing set in peripheral blood from the SLE, RA and HC groups. (A) Average expression of hsa_circ_0082688 in patients with SLE was significantly increased compared with the HC and RA groups. (B) Average expression of hsa_circ_0082689 in patients with SLE was significantly increased compared with the HC and RA groups. HC, healthy controls; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.

Figure 5.

Correlation of the expression of identified circRNAs with SLE clinical characteristics. (A) Expression of hsa_circ_0082688 was negatively associated with C3 in patients with SLE. (B) Expression of hsa_circ_0082689 was negatively associated with WBC in patients with SLE. (C) Expression of hsa_circ_0082688 was negatively associated with the number of monocytes in patients with SLE. (D) Expression of hsa_circ_0082689 was negatively associated with the number of monocytes in patients with SLE. (E) Expression of hsa_circ_0082689 was negatively associated with number of neutrophils in patients with SLE. circRNAs, circular RNAs; SLE, systemic lupus erythematosus; WBC, white blood cell.