The mRNA Expression Status of Dopamine Receptor D2, Dopamine Receptor D3 and DARPP-32 in T Lymphocytes of Patients with Early Psychosis

Abstract

Peripheral blood lymphocytes are an attractive tool because there is accumulating evidence indicating that lymphocytes may be utilized as a biomarker in the field of psychiatric study as they could reveal the condition of cells distributed in the brain. Here, we measured the mRNA expression status of dopamine receptor D2 (DRD2), DRD3, and dopamine and cyclic adenosine 3′,5′-monophosphate regulated phosphoprotein-32 (DARPP-32) in T lymphocytes of patients with early psychosis by quantitative real-time polymerase chain reaction (q-PCR) and explored the relationships between their mRNA levels and the psychopathological status of patients. The present study demonstrated that the mRNA expression levels of DRD3 in T lymphocytes were significantly different among controls, and in patients with psychotic disorder not otherwise specified (NOS) and schizophrenia/schizophreniform disorder. However, no significant differences in mRNA expression levels of DRD2 and DARPP-32 were found among the three groups. We found a significant positive correlation between the DRD2 mRNA level and the score of the excited factor of the Positive and Negative Syndrome Scale (PANSS) in patients with schizophrenia/schizophreniform disorder. These findings suggest that DRD3 mRNA levels may serve as a potential diagnostic biomarker differentiating patients with early psychosis from controls.

Immunomodulatory Effects Mediated by Dopamine

“…Further, DRD3 expression correlated with the excitement factor on the PANSS in patients with schizophrenia/schizophreniform disorder. According to the authors, DRD3 mRNA levels can be used as a diagnostic marker to differentiate patients with early psychosis from healthy controls [ 237 ].…”

The involvement of DARPP-32 in the pathophysiology of schizophrenia

“…Unfortunately, there are on this topic inconclusive reports as well. No change in DARPP-32 protein levels were found in schizophrenic prefrontal and cingulate cortex and T lymphocytes of elderly patients with schizophrenia [ 75 , 76 ]. Mutation analysis of DARPP-32 gene indicate that it is not a major susceptibility gene for schizophrenia [ 77 ].…”

Research Article Frequency of <i>ANKK1</i>, <i>DRD2</i>, <i>DRD3</i> gene polymorphisms in refractory schizophrenia patients

“…Regarding rs6280 polymorphism alone, a recent study demonstrated that levels of DRD3 mRNA on T lymphocytes were significantly different between controls and individuals with unspecified psychotic disorder and SCZ (Cui et al, 2015). Another study showed that there is an excess of the C allele and homozygotes for this allele in patients with tardive dyskinesia (an irreversible adverse effect of the antipsychotic medication) (Utsunomiya et al, 2012).…”

“…To try to understand the refractoriness of several drugs a pharmacogenetic approach has been used. Pharmacogenetics place genetic variation as a possible reason for the absence or poor response to adequate medication (Cui et al, 2015). Large-scale genomic association studies of SCZ identified 108 genetic loci associated with this disorder.…”