Alpha- and beta-synucleins mRNA expression in lymphocytes of schizophrenia patients.

Alpha-synuclein is largely, but not entirely, expressed in the central nervous system. A high concentration of alpha-synuclein in presynaptic terminals can mimic the normal function of endogenous alpha-synuclein in regulating synaptic vesicle mobilization at nerve terminals. Beta-synuclein protein is seen primarily in brain tissue and it is suggested that beta-synuclein acts as an inhibitor of alpha-synuclein aggregation, which occurs in neurodegenerative diseases. With respect to the role of synucleins in neurologic diseases such as Parkinson's disease, we decided to study the changes of alpha- and beta-synucleins in schizophrenia patients in relation to a control group. For this purpose, total RNA was extracted from the lymphocytes of patients and controls and then cDNA was synthesized and used for real-time polymerase chain reaction. Calculation of the relative expression of alpha- and beta-synucleins showed downregulation in patients in comparison to the control group. Independent two-tailed t-test showed that beta-synuclein mRNA expression in the control group was significantly higher than that in the patient group (p < 0.01), but downregulation of alpha-synuclein gene was not significant. Therefore, a significant downregulation of beta-synuclein mRNA expression appears to be a suitable biomarker for the diagnosis of schizophrenia.