Downregulation of long non-coding RNAs in patients with bipolar disorder

Abstract

The abnormal function of signaling cascades is currently a candidate in the pathophysiology of bipolar disorder (BD). One of the factors involved in activating these signals is oxidative stress. Some long non-coding RNAs (lncRNA) are involved in the oxidative stress. In this study, we compared expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the peripheral blood mononuclear cells (PBMC) from BD patients (n = 50) and healthy individuals (n = 50). Expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT were significantly reduced in patients with BD compared to controls. In sex-based analyses, down-regulation of these lncRNAs was revealed only in male BD patients compared to male healthy subjects. Also, in BD patients, all three lncRNAs showed a significant pairwise positive correlation in expression level. The area under curve values for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT was 0.66, 0.75, and 0.66, respectively. Thus, the ROC curve analysis showed that lncRNA-ROR might serve as a diagnostic biomarker for distinguishing between BD patients and controls. Altogether, the current study proposes a role for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the pathogenesis of bipolar disorder. Moreover, the peripheral expression of these lncRNAs might be useful as potential biomarkers for BD.

Figure 1

Expression analysis of lncRNAs in the PBMCs. The relative expression (Fold change) of linc-p21 (A), lncRNA-ROR (B), and linc-PINT (C). Expression of lncRNAs was significantly down-regulated in BD patients compared to controls. Gene expression levels of each sample were normalized relative to GAPDH expression. The relative expression of transcripts was obtained using the formula 2 ^-ΔΔCt and t-test.

Figure 2

ROC curve analysis of lincRNA-p21 (A) lncRNA-ROR (B) and lincRNA-PINT (C). AUC: area under curve.