SELENBP1 expression in the prefrontal cortex of subjects with schizophrenia

Abstract

Selenium binding protein 1 (SELENBP1) messenger RNA (mRNA) has previously been shown to be upregulated in the brain and blood from subjects with schizophrenia. We aimed to validate these findings in a new cohort using real-time PCR in Brodmann's Area (BA) 9, and to determine the disease specificity of increased SELENBP1 expression by measuring SELENBP1 mRNA in subjects with major depressive disorder and bipolar disorder. We then extended the study to include other cortical regions such as BA8 and BA44. SELENBP1 mRNA was higher in BA9 (P = 0.001), BA8 (P = 0.003) and BA44 (P = 0.0007) from subjects with schizophrenia. Conversely, in affective disorders, there was no significant difference in SELENBP1 mRNA in BA9 (P = 0.67), suggesting that the upregulation may be diagnosis specific. Measurement of SELENBP1 protein levels showed that changes in mRNA did not translate to changes in protein. In addition, chronic treatment of rats with antipsychotics did not significantly affect the expression of Selenbp1 in the cortex (P = 0.24). Our data show that elevated SELENBP1 transcript expression is widespread throughout the prefrontal cortex in schizophrenia, and confirm that this change is a consistent feature of schizophrenia and not a simple drug effect.

Figure 1

SELENBP1 protein in schizophrenia. (a) Western blot of SELENPB1 expression in SH-SY5Y cells transfected with human SELENBP1 (lane 1, 5 μg and lane 2, 10 μg protein) and human central nervous system (CNS) tissue (lane 3, 20 μg and lane 4, 30 μg protein). (b) SELENBP1 protein expression in BA9, BA44 and BA8 from subjects with schizophrenia (Scz; ▴) and control (Cntrl; o). Error bars represent mean±s.e.m. ***P<0.001, two-way analysis of variance.

Figure 2

SELENBP1 messenger RNA (mRNA) in schizophrenia and affective disorders. SELENBP1 mRNA expression in (a) BA9, (b) BA44 and (c) BA8 from subjects with schizophrenia (Scz; ▴) and control (Cntrl; O), as well as in (d) BA9 from subjects with major depressive disorder (MDD; ♦), bipolar disorder (BP; ▪) and control (□). Error bars represent mean±s.e.m. **P<0.01 and ***P<0.001; t-test.

Figure 3

Selenbp1 messenger RNA (mRNA) in antipsychotic-treated animals. Selenbp1 mRNA expression in central nervous system from rats treated with vehicle (Veh), 10 mg kg⁻¹ per day chlorpromazine (Clp), 10 mg kg⁻¹ per day thioridazine (Thd) or 1.0 mg kg⁻¹ per day haloperidol (Hal). Error bars represent mean±s.e.m.