Early growth response 1 (EGR1) is downregulated in peripheral blood from patients with major psychiatric disorders

Abstract Objective: To evaluate relative expression of genes with the potential to translate environmental stimuli into long-term alterations in the brain, namely early growth response (EGR)1, EGR3, and cryptochrome circadian regulator (CRY)2 genes, in peripheral blood from patients with bipolar disorder (BD), schizophrenia (SZ), and major depressive disorder (MDD) and from healthy controls (HC). Methods: Thirty individuals ranging from 18 to 60 years old were recruited for each group (BD, SZ, MDD, or HC) from a Brazilian public hospital. These individuals’ peripheral blood was collected and EGR1, EGR3, and CRY2 gene expression analyzed by real-time polymerase chain reaction (qPCR). Results: EGR1 mRNA levels were significantly lower in psychiatric patients when compared to HC, but there were no differences for EGR3 or CRY2. Exploring the findings for each diagnosis separately, there were only significant differences between each of the diagnostic groups and controls for EGR1, which was lower in BD, MDD, and SZ compared to HC. No significant correlations were found between gene expression and clinical features. Conclusion: EGR1 is downregulated in psychiatric patients, regardless of diagnosis, and may be a potential common target in major psychiatric disorders. As a transcription factor, EGR1 modulates many other genes and participates in crucial neuronal and synaptic processes, such as plasticity, neurotransmitter metabolism, vesicular transport, and signaling pathways. The study of EGR1 and its upstream regulators might lead to potential new therapeutic targets in psychiatry.