Abnormalities of SNARE Mechanism Proteins in Anterior Frontal Cortex in Severe Mental Illness

ISSN： 1460-2199

Source： Cerebral Cortex, Vol.12, Iss.4, 2002-04, pp. : 349-356

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

A fundamental molecular component of neural connectivity is the SNARE (SNAP receptor) protein complex, which consists of three proteins, syntaxin, SNAP-25 and VAMP. Under appropriate conditions, the SNARE complex can be formed in vitro. To investigate the hypothesis that dysregulation of SNARE proteins or their interactions could be abnormal in severe mental disorders, the three SNARE proteins and the complex were studied in post-mortem anterior frontal cortex homogenates. An ELISA was used to quantify SNARE protein immunoreactivities in cortical homogenates from four groups: patients with schizophrenia who died of causes other than suicide (n = 6), patients with schizophrenia and suicide (n = 7), patients with depression and suicide (n = 11), and controls (n = 11). Differences between groups in patterns of SNARE protein immuno-reactivities were demonstrated [Wilks' Lambda F(9,68) = 3.57, P = 0.001]. Protein-by-protein analyses indicated a significant reduction in SNAP-25 immunoreactivity in the schizophrenia non-suicide group [28% decrease relative to controls, F(3,31) = 6.45, P = 0.002, Student–Newman–Keuls test, P < 0.01].="" the="" intercorrelations="" between="" snare="" protein="" and="" synaptophysin="" immunoreactivities="" were="" high="" in="" controls,="" but="" lower="" in="" the="" other="" groups,="" further="" indicating="" disturbances="" in="" relationships="" between="" these="" proteins.="" the="" extent="" of="" snare="" complex="" formation="">in vitro was studied using immuno-blotting. Significant differences related to group membership were observed for the SNARE complexes identified by SNAP-25 [Wilks' Lambda F(3,31) = 4.76, P = 0.008] and by syntaxin immunostaining [Wilks' Lambda F(3,31) = 9.16, P = 0.0002]. In both groups with suicide as a cause of death, relatively more SNAP-25 and syntaxin was present in the heterotrimeric SNARE complex than in other molecular forms. These abnormalities in the SNARE complex could represent a molecular substrate for abnormalities of neural connectivity in severe mental disorders.