Detection of circulating miRNA levels in schizophrenia.

Objective: Diagnosis of schizophrenia is currently dependent on symptom-based criteria and lacks objective indicators. In this study, the authors investigated whether circulating miRNA can serve as a diagnostic biomarker for schizophrenia.

Methods: Global plasma miRNAs were profiled in a test cohort of 164 schizophrenia patients and 187 control subjects, using Solexa sequencing, TaqMan Low Density Array, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. The captured miRNAs were then validated by qRT-PCR assays in an independent cohort of 400 schizophrenia patients, 213 control subjects, and 162 patients with nonschizophrenia psychiatric disorders; the 400 schizophrenia patients underwent a 12-month follow up study of regular treatment with an atypical antipsychotic (risperidone and aripiprazole).

Results: The global plasma miRNA screening revealed eight miRNAs that were up-regulated in schizophrenia, as revealed by both assay platforms. The qRT-PCR analysis showed the up-regulation of miR-130b and miR-193a-3p in schizophrenia but not in nonschizophrenia disorders.

Conclusions: The up-regulation of miR-130b and miR-193a-3p is a state-independent biomarker for schizophrenia, and these two miRNAs could be used to develop a diagnostic tool for schizophrenia.