ABSTRACT
Polyclonal (PAb) and monoclonal (MAb) antibodies to CT2-epitope of the C-terminal fragment of serotonin transporter (SERT) protein were used to study the levels and molecular heterogeneity of platelet SERT in healthy donors and patients with affective (AD) and somatoform (SD) disorders, schizoaffective disorder (SAD) and schizophrenia. SERT was found to exist as high molecular wight (HMW) and low molecular weight (LMW) forms separated after electrophoresis. The levels of HMW and LMW forms of SERT were significantly, decreased in mentally ill patients as compared to healthy individuals. Unlike PAb, horse radish peroxidase (HRP)-conjugated MAbs were more sensitive and specific to SERT and could detect the LMW form of SERT as a duplet protein form with MW about 40 and 43 kDa. The MAb to CT2 C-terminal fragment of SERT conjugated with HRP is considered to be a new valuable tool for further investigation of SERT expression, properties, and posttranslation modification in the controls and in patients with different psychopathology.
Subject(s)
Blood Platelets/metabolism , Carrier Proteins/blood , Membrane Glycoproteins/blood , Membrane Transport Proteins , Mental Disorders/metabolism , Nerve Tissue Proteins , Serotonin/metabolism , Adult , Animals , Antibodies, Monoclonal , Carrier Proteins/genetics , Carrier Proteins/metabolism , Electrophoresis , Epitopes , Female , Genetic Heterogeneity , Humans , Immunoenzyme Techniques , Male , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Mental Disorders/blood , Mental Disorders/genetics , Mice , Middle Aged , Molecular Weight , Mood Disorders/blood , Mood Disorders/genetics , Mood Disorders/metabolism , Protein Transport , Schizophrenia/blood , Schizophrenia/genetics , Schizophrenia/metabolism , Sensitivity and Specificity , Serotonin Plasma Membrane Transport Proteins , Somatoform Disorders/blood , Somatoform Disorders/genetics , Somatoform Disorders/metabolismABSTRACT
The role of serotonin transporter (SERT) protein in the development of somatoform disorders (SD) was investigated. An association study was performed in terms of the evaluation of the level of SERT immunoreactive (IR-SERT) protein using site-specific antibodies directed at SERT C-terminus fragment, poorly conserved among the other cotransporters. The level of the anxious symptomatology was also estimated in the patients with SD. 22 patients, who met DSM-IV criteria for somatoform disorders, and 32 normals were examined. In platelets from normals, IR-SERT protein migrated as a difuse band between 68 and 105 kDa, and a major sharper band at 43 kDa. Almost complete disappearance of platelet 43 kDa IR-SERT protein band was observed in most of the patients with SD. These findings permitted to suggest a possibility of either biosynthetic or processing abnormality of SERTs in the affected population, that might reflect a dysfunction of serotonin neurotransmission in CNS of the patients with SD.
Subject(s)
Blood Platelets/metabolism , Serotonin/metabolism , Somatoform Disorders/metabolism , Adult , Biological Transport, Active/physiology , Female , Humans , Immunoblotting , Male , Middle Aged , Psychiatric Status Rating Scales , Somatoform Disorders/diagnosisABSTRACT
To elucidate the role of serotonin transporter (SERT) protein as a candidate target for somatoform disorders (SD), we have performed an association study of the SERT immunoreactive (IR-SERT) protein level by using site-specific antibodies directed at C-terminus epitope poorly conserved among other cotransporters. 22 patients who met DSM-IY criteria for SD and 32 healthy volunteers matched in sex and age participated in the study. In platelets from all healthy donors, IR-SERT proteins migrates as a diffuse band between 75 and 102 kDa and a major sharper band at 43 kDa. We revealed almost complete disappearance of platelet 43 kDa IR-SERT protein in all patients with SD. All patients were rated with Hamilton Depressive Rating Scale (HDRS). There were found a significant negative correlation between residual IR-SERT 43 kDa protein level and HDRS Scores [r = -0.83; P < 0.000001]. These findings suggest that a biosynthetic or processing abnormality may exist in SERTs in the affected population and may reflect the dysfunction of serotonin neurotransmission in CNS.
