No abstract

Amounts of glutamate metabolizing enzymes such as glutamate dehydrogenase (GDH), glutamine synthetase (GS), GS-like protein (GSLP), and phosphate-activated glutaminase (PAG) were compared in prefrontal cortex of control subjects and patients with Alzheimer disease (AD). The target proteins were quantified by ECL-Western immunoblotting in extracts from brain tissue prepared by two different techniques separating enzymes preferentially associated with cytoplasm (GDH I and II isoenzymes, GS, and partially GSLP) and membrane (GDH III, PAG, and partially GSLP) fractions. Amounts of all listed enzymes were found significantly increased in the patient group compared with controls. Some links between the measured values were observed in the control, but not in the AD patient group. The results may suggest for the pathological interruption of regulatory relations between distinct enzymes of glutamate metabolism in brain of AD patients.

Background Purpose of study is revealing significant differences in serum proteomes in schizophrenia and bipolar disorder (BD). Results Quantitative mass-spectrometry based proteomic analysis was used to quantify proteins in the blood serum samples after the depletion of six major blood proteins. Comparison of proteome profiles of different groups revealed 27 proteins being specific for schizophrenia, and 18 – for BD. Protein set in schizophrenia was mostly associated with immune response, cell communication, cell growth and maintenance, protein metabolism and regulation of nucleic acid metabolism. Protein set in BD was mostly associated with immune response, regulating transport processes across cell membrane and cell communication, development of neurons and oligodendrocytes and cell growth. Concentrations of ankyrin repeat domain-containing protein 12 (ANKRD12) and cadherin 5 in serum samples were determined by ELISA. Significant difference between three groups was revealed in ANKRD12 concentration ( p = 0.02), with maximum elevation of ANKRD12 concentration (median level) in schizophrenia followed by BD. Cadherin 5 concentration differed significantly ( p = 0.035) between schizophrenic patients with prevailing positive symptoms (4.78 [2.71, 7.12] ng/ml) and those with prevailing negative symptoms (1.86 [0.001, 4.11] ng/ml). Conclusions Our results are presumably useful for discovering the new pathways involved in endogenous psychotic disorders. Electronic supplementary material The online version of this article (10.1186/s12864-019-5848-1) contains supplementary material, which is available to authorized users.

Creatine kinase (CK) is responsible for the creatine/creatine phosphate level which that is known to alter in the brain of patients with schizophrenia. A comparative estimation of CK enzymatic activity and immunoreactivity of CK BB was carried out in readily soluble extracts from frontal cortex, anterior and posterior cingulate cortex, hippocampus and cerebellum from brains of individuals with schizophrenia versus normal controls. CK activity was determined using a commercial diagnostic kit. CK BB immunoreactivity was evaluated by ECL -immunoblotting using monoclonal antibody. A drastic drop of CK activity and CK BB immunoreactivity was observed in all the examined brain areas in schizophrenia patients compared to controls (p<0.01), with the maximum drop in the cerebellum. The reduction was independent of age, postmortem interval or chlorpromazine equivalent. The decreased level of CK BB in schizophrenia was confirmed by purification of CK BB from brains of patients with schizophrenia and control brains: the yield of the purified enzyme was significantly lower in schizophrenia, wherein molecular masses of CK B-subunits were equal. Possible causes and consequences of the decrease in CK BB level observed in brain of patients with schizophrenia are discussed.

Enzymes of glutamate and GABA metabolism in postmortem cerebellum from patients with Alzheimer's disease (AD) have not been comprehensively studied. The present work reports results of original comparative study on levels of phosphate-activated glutaminase (PAG) and glutamic acid decarboxylase isoenzymes (GAD65/67) in autopsied cerebellum samples from AD patients and matched controls (13 cases in each group) as well as summarizes published evidence for altered levels of PAG and GAD65/67 in AD brain. Altered (decreased) levels of these enzymes and changes in links between amounts of these enzymes and other glutamate-metabolizing enzymes (such as glutamate dehydrogenase and glutamine synthetase-like protein) in AD cerebella suggest significantly impaired glutamate and GABA metabolism in this brain region, which was previously regarded as not substantially involved in AD pathogenesis.