Plasma circRNA HIPK2 as a putative biomarker for the diagnosis and prediction of therapeutic effects in major depressive disorder

Circular RNAs (circRNAs) are a prevalent type of non-coding RNAs exhibiting extensive expression in mammalian cells. Owing to their involvement in diverse pathophysiological mechanisms of major depressive disorder (MDD) and their inherent stability in peripheral blood, circRNAs have emerged as potential biomarkers of considerable significance. This study aimed to identify and validate circular RNA HIPK2 (circHIPK2) in MDD patients and to investigate its potential as a biomarker for the diagnosis and prognosis of MDD.Patients with MDD (n = 81) and healthy controls (HCs) (n = 48) were recruited for our study (October 2022 to June 2023). The expression of circHIPK2 in plasma was assessed using absolute quantitative polymerase chain reaction (qPCR).The expression of circHIPK2 in plasma of patients with MDD exhibited a significant increase compared to HCs. The circHIPK2 levels showed an area under the curve (AUC) of 0.796, corresponding to a specificity of 97.9% and a sensitivity of 60.4% in diagnosing MDD. Additionally, the rate of change in circHIPK2 over a 14-day period exhibited an AUC curve of 0.819, indicating its predictive value for antidepressive effects.CircHIPK2 could serve as a potential biomarker for diagnosing MDD and predicting therapeutic effects of MDD.