PLATELETS AS A MODEL OF NEURONS IN BIOCHEMICAL STUDIES IN MENTAL DISORDERS
Review. Platelets are non-nuclear blood cells, the main function of which is initiation and participation in clotting (blood coagulation cascade). Platelets and neurons differ in their embryonic origin, differentiation, function and localization, but the proteomes of neurons and platelets are similar. Some regulatory proteins are found in both neurons and platelets (for example, reelin, amyloid precursor protein, brain-derived neurotrophic factor). Platelets also contain proteins found in neurons: receptors and neurotransmitter transporters, enzymes of neurotransmitter metabolism (for example, monoamine oxidase, glutamate dehydrogenase), enzymes - components of antioxidant glutathione system (glutathione reductase, glutathione peroxidase, glutathione-S-transferase), components of protein phosphorylation signaling pathways (protein kinases and their protein substrates). Platelets contain active mitochondria with functionally complete respiratory electron transport chain, and unidirectional changes in the energy metabolism of the brain and changes in mitochondrial platelet activity were found in several pathological cerebral processes. Metabolic profiles of neurons and platelets are similar, in fact, platelets contain a number of neurotransmitters, including y-aminobutyric acid, glutamate, serotonin, adrenaline, dopamine, and histamine. The authors support the conception of platelet considering as a model of individual biochemical processes in the brain and the possibility of their use for studying and simulation of some brain pathologies, including mental, neurodegenerative, and neurodevelopmental disorders (schizophrenia, depression, Alzheimer’s disease, autism). The authors are currently searching for proteins that can be used as biomarkers of pathological conditions in the brain for the differential diagnosis of mental illness and therapeutic response predicting. Platelets are also used to study the effect of medicines on biochemical processes in clinical trials and to monitor the therapeutic responses.