Alterations of miR-132 are novel diagnostic biomarkers in peripheral blood of schizophrenia patients

Alterations in microRNAs (miRNAs) have been considered to have diagnostic implications in most diseases, but few studies have reported dysregulated miRNAs in schizophrenia (SCZ). In order to observe an association between miRNAs and SCZ, this study was designed to investigate expression profiling of miRNAs in peripheral blood mononuclear cells (PBMCs). miRNA microarray technology was employed to compare the expression of miRNAs in PBMCs from SCZ patients (n = 105) and normal controls (n = 130), and real-time quantitative polymerase chain reaction (QPCR) was used to analyze the results. Several important miRNA levels were examined before and after antipsychotic treatment in first-onset SCZ patients. In addition, an SCZ-like rat model was established using dizocilpine (MK-801), and miR-132 expression in PBMCs and whole-brain tissue from SCZ-like rats was studied using QPCR. In humans, dysregulated miRNAs were observed before treatment and QPCR verified that miR-132, miR-134, miR-1271, miR-664⁎, miR-200c and miR-432 levels were significantly decreased (P < 0.01 for all) in PBMCs of SCZ patients compared with healthy controls. After antipsychotic treatment there was a marked increase in miR-132 (P < 0.01), miR-664⁎ (P < 0.05) and miR-1271 (P < 0.05) levels in SCZ patients compared with the levels before treatment. In the animal assays, miR-132 levels declined in PBMCs and whole-brain tissues (both P < 0.05) of the SCZ-like rats compared to controls. For the first time, our results suggest that miR-132 is a potential and superior biomarker in peripheral blood that will allow discrimination of SCZ patients from healthy controls.