Motor and Cognitive Functions in Aging C57BL/6 Mice: Association with Activity of the Monoaminergic Systems in the Cerebellum and Frontal Cortex.

The activity in the open field, short- and long-term memory in the novel object recognition test, and gait features were evaluated in 6- and 12-month-old male C57BL/6 mice. The levels of norepinephrine, dopamine, serotonin, and their metabolites were determined in the cerebellum and frontal cortex. In the observed age range, a decrease in locomotion speed, impairment of gait initiation and stability, and long-term memory deficit were revealed. In the cerebral cortex, reduced levels of dopamine and its metabolites and accelerated metabolism of all neurotransmitters under study were found. In the cerebellum, the content of all studied monoamines was elevated, while dopamine metabolism was decelerated. Analysis of correlations between the neurochemical and behavioral parameters showed that the mechanisms of compensation of brain functions during the early aging may be associated with an increase in activity of the monoaminergic systems in the cerebellum.

Analysis of NAPA Gene Expression in Brain Structures of Wistar Rats during the Formation of Long-Term Spatial Memory and Physical Activity under Stress Situation.

In the cerebellum, hippocampus, and prefrontal cortex of mature male Wistar rats with trained spatial navigational skill in the Morris water maze, the transcriptional activity the NAPA gene that regulates the transport and secretion of synaptic vesicles, release of neurotransmitters, and protein degradation was determined by real-time PCR. Animals subjected to forced swimming in a time-matched regime (active control) and naïve rats were used as the comparison groups. Suppression of NAPA gene activity was found in the hippocampus and cerebellum of the active control group, while navigation skill training led to a significant increase in gene expression in all brain structures under study. The findings suggest the existence of specific mechanisms regulating NAPA gene activity during the formation of spatial memory and adaptive behavior under stress conditions.

Cerebral Expression of the Neuregulin-1 Gene NRG1 during Induced Spatial Memory Impairment and Its Reversal in Aging Mice.

We studied the effects of chronic intranasal administration of amyloidogenic fibrils of the proinflammatory protein S100A9 alone or in combination with glutamate antibodies on the expression of the neuregulin-1 gene (NRG1), a regulator of various physiological processes, in particular, regulation of neurogenesis and apoptosis, in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of long-term memory disturbances. Under conditions of amnesia induced by S100A9 fibrils, pronounced (>90%) blockade of the expression of the NRG1 gene was found in all cerebral structures. Glutamate antibodies prevented/corrected disturbances in the cerebral expression of the NRG1 gene, thereby maintaining the activity of the NRG1/ErbB molecular signaling system, probably associated with the formation of spatial memory.

Effects of Antibodies to Glutamate on Cerebral Expression of the Tnfrsf1A Gene under Conditions of Spatial Amnesia Induced by Proinflammatory Protein S100A9 Fibrils in Aging Mice.

Proinflammatory S100A9 protein is a promoter of inflammation-linked neurodegeneration and the Tnfrsf1A gene encodes the TNF receptor 1A that binds TNFα to function as a regulator of inflammation. We studied the effects of chronic intranasal administration of in vitro prepared S100A9 fibrils alone or in combination with anti-glutamate antibodies on the expression of the Tnfrsf1A gene in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of impaired spatial memory. A differential cerebral pattern of Tnfrsf1A gene activity and its modification by S100A9 fibrillar structures were observed: inhibition of Tnfrsf1A gene expression in the hippocampus and cerebellum and its activation in the prefrontal cortex. Anti-glutamate antibodies normalized the expression of the Tnfrsf1A gene in the prefrontal cortex by affecting the TNF signaling pathway and preventing the development of inflammation.

Delayed Behavioral and Neurochemical Effects of Anti-Glutamate Antibodies in Aging C57BL/6 Mice.

We analyzed delayed effect of intranasal administration of anti-glutamate antibodies on mnestic function and tissue concentrations of neurotransmitters in the hippocampus and prefrontal cortex in aging C57BL/6 mice. It was found that after 14-day administration of anti-glutamate antibodies, improvement of the passive avoidance conditioning persisted for 7 days after the treatment was discontinued. In 7 days after discontinuation of treatment, increased content of dopamine and its metabolites as well as aspartic acid and taurine was observed in the hippocampus of mice treated with anti-glutamate antibodies. In the prefrontal cortex, administration of anti-glutamate antibodies had no effect on the levels of neurotransmitters, but increased the concentration of glutamate.

Prognostic Model of Prehypertension Risk Based on Molecular Markers.

The prognostic models assessing the risk of prehypertension in coming 1-2-year period for 30-60-year-old subjects were developed with the help of computer recognition technology using 6 recognition methods. These models are based on the content of molecular markers in blood serum and the risk factors for the development of prehypertension in men and women who had "optimal" BP for last 3 years and in patients with newly diagnosed prehypertension. The models were compared for their prediction power. The most effective model was obtained with gradient boosting method based on the content of molecular markers. It is characterized with a high predictive power (ROC AUC=0.76), specificity (96.4%), and overall accuracy (86.6%) accompanied with close relationship between prognosis and actual symptoms of prehypertension (p=0.001).

Antibodies to Glutamate Facilitate Spatial Memory Formation in the Morris Water Maze in Aging C57BL/6 mice.

Intranasal administration of antibodies to glutamate in a dose of 250 µg/kg for two weeks facilitated spatial learning and memory formation in the Morris water maze in aging C57BL/6 mice. In animals treated with glutamate antibodies, the content of serotonin and dopamine metabolites 3-MT and HVA in the hippocampus decreased, but no changes in the metabolism of neurotransmitter acids were revealed. In the prefrontal cortex, dopamine level decreased and the content of its metabolite DOPAC increased; in parallel, an increase in excitatory and inhibitory amino acids (aspartic acid, glutamate, glycine, taurine, and GABA) was observed.

Serum Level of HLDF24 Peptide as an Objective Marker of Prehypertension.

The concentrations of the key factors of molecular pathogenesis of prehypertension (angiotensin II, HLDF24, S100b, endothelin, autoantibodies to these molecules, and VEGF) were analyzed in subjects with optimal BP (<120/80 mm Hg) and prehypertension (120-139/80-89 mm Hg). Comparative and correlation analysis of the levels of these molecules was performed. A statistically significant decrease in HLDF24 level in prehypertension in comparison optimal BP was observed. Specific features and interactions between the studied factors in optimal BP and in prehypertension were studied. The mechanisms underlying the observed associations between serum concentration of HLFF24 and the development of prehypertension were discussed.

Effect of Antibodies to Glutamate on Age-Related Memory Changes in C57Bl/6 Mice.

Chronic intranasal administration of antibodies to glutamate to aging C57Bl/6 mice improved passive avoidance conditioning, had no effect on horizontal and vertical locomotor activity, but slowed locomotion in the open-field test. Administration of antibodies to glutamate increased the content of dopamine and its metabolites in mouse hippocampus, but had no effect on the metabolism of neurotransmitter amino acids. In the frontal cortex, antibodies to glutamate did not affect neurotransmitter metabolism, but increased the level of both excitatory and inhibitory amino acids without changing their ratio.

Pattern of Notch2, Numb, and Cas8 Gene Expression in Relevant Structures of the Rat Brain during Formation of Spatial Memory.

The expression of Notch2, Numb, and Cas8 genes, whose protein products are involved in regulation of neurogenesis/neuroapoptosis processes, was studied in the relevant cerebral structures of male Wistar rats trained in a spatial habit. The formation of long-term spatial memory was found to be associated with the formation of a specific pattern of transcription activity of the studied genes in different brain structures. The maximum expression of Notch2 gene was found in the hippocampus and cerebellum, the maximum expression of Numb was detected in the prefrontal cortex and cerebellum, and the maximum expression of Cas8 was revealed in the prefrontal cortex of trained animals.

Antibodies to Glutamate Reversed the Amnesic Effects of Proinflammatory S100A9 Protein Fibrils in Aged C57Bl/6 Mice.

Chronic intranasal administration of fibrillar structures of proinflammatory S100A9 protein impaired passive avoidance learning in old C57Bl/6 mice. Combined treatment with S100A9 fibrils and antibodies to glutamate was followed by an increase in horizontal locomotor activity of animals in the open-field test and did not disturb spatial memory.

Molecular markers of arterial hypertension in patients with normotony, pre-hypertension and hypertension.

We studied concentrations of angiotensin II, HLDF24 peptide, endothelin proteins, S100B, and autoantibodies to them and serum levels of blood natriuretic peptide in patients with different categories of "normal" arterial BP and hypertension. The relationship between blood levels of the above factors and normotony, pre-hypertension, and hypertension in the examined groups was analyzed. The results suggest that the studied molecular factors can serve as potential predictors of arterial hypertension and used for personalized hypertension risk assessment.

Content of S100b protein, HLDF24 peptide and autoantibodies to these factors as potential biomarkers for arterial hypertension in blood serum of healthy people.

The content of S100b protein, HLDF24 peptide, and autoantibodies to these factors in blood serum was measured in healthy individuals (35-64-year-old men and women) with various levels of "normal" BP. Significant differences in the amount of these molecular factors were found in individuals with various categories of BP. We revealed age-related and gender differences in the content of molecular factors in the serum. Our results indicate that variations in the concentration of S100b, HLDF24, and autoantibodies to these factors in blood serum from adult people can serve as a reliable criterion for the risk of arterial hypertension.

Involvement of HLDF protein and anti-HLDF antibodies in the mechanisms of blood pressure regulation in healthy individuals and patients with stable hypertension and hypertensive crisis.

We studied the relationships between the blood serum levels of human leukemia differentiation factor HLDF, idiotypic and anti-idiotypic antibodies to HLDF, and clinical indicators of cardiovascular function in apparently healthy individuals and patients with essential hypertension and cerebral hypertensive crisis. Markedly reduced HLDF levels and anti-HLDF antibody titers were found in the blood of the examined patients. Correlations between HLDF levels, duration of hypertension, and systolic and diastolic BP were revealed. These findings suggest that the studied molecular factors are involved in the mechanisms of BP regulation under normal conditions and during hypertension development. The protein HLDF and anti-HLDF antibodies can be considered as biomarkers for early diagnosis of hypertension and its cerebral complications.

Regional features of the expression of genes involved in neurogenesis and apoptosis in the brain of adult rats.

The expression of mRNA of genes involved in neurogenesis and apoptosis (Apaf1, Ascl1, Bax, Bcl2, Casp3, Casp8, Casp9, Dffb, Myh10, Naip2, Napa, Notch2, Numb, Pura, S100a6, Tnf) in the prefrontal cortex, hippocampus, and cerebellum was studied in adult rats. The content of mRNA of these genes (except Apaf1) was several-fold higher in the cerebellum than in the hippocampus and brain cortex. In the hippocampus, the expression of Apaf1 was significantly lower than in the prefrontal cortex, while the expression of Ascl1, Pura, S100b, and Tnf was higher. Regional differences in the direction, strength, and numbers of significant correlations between the expression of the studied genes were detected. Documented differences in gene expression were regarded as validation of the structural and functional cooperation of neurogenesis and apoptosis at the molecular genetic level.

[Serum immunoboichemical markers in patients suffered with hypertension-induced cerebrovascular diseases].

Complex evaluation neurotrophic protein S100b, differentiation factor HLDF, idio-and antiidiotypic antibodies against these proteins in patient sera with hypertension-induced cerebrovascular disorders was performed by ELISA. In patients with essential hypertension, cerebral hypertensive crisis and ischemic stroke S100b and anti-S100b concentration was found to be higher, whereas HLDF and anti-HLDF ones were lower compared with control. Different dynamics of S100b, HLDF content and antibody level was shown within 21 days of observation. These findings may be useful in further diagnostic and prognostic studies of hypertension-induced cerebrovascular disorders.

[Morphological features of regenerative-reparative processes in the cornea exposed to synthetic analogues of endogenous peptide fragments of protein S100b in an experiment].

The effects of two 5-membered (SP5, SP6) endogenous synthetic peptide fragments of protein S100b on the course of regenerative-reparative processes in the corneas of Wistar rats were morphologically studied after making a graduated injury. Conjunctival or endonasal injection of the peptides was made at two concentrations of 10(-6) and 10(-8) M. The study peptides were found to have a modulating effect on regenerative-reparative processes regardless of the route of administration and to induce accelerated and qualitative corneal wound healing as compared with the controls. The specific feature of SP5 was the formation of a fibroblastic membrane. When SP5 was injected at a concentration of 10(-6) M, the membrane was more pronounced and occupied the whole area of keratectomy whereas when this peptide was administered at a concentration of 10(-8) M, its formation was observed in the deep and middle corneal layers. The most marked effect of SP6 revealed during the study was the formation of newly-formed vessels over the entire wound surface independently of the concentration of the injected substance. Of the two study peptide fragments, SP5 is, in the authors' opinion, promising for clinical application. Significant keratocytic proliferation noted in the use of SP5 at a concentration of 10(-6) M may be used to accelerate scarring when the sclera and cutaneous covering are damaged. The effects detected with administration of SP6 at two concentrations were regarded as negative as they did not answer the purpose set during the study performed.

Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients.

Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.

Biochemical markers of apoptosis in different parts of the brain during learning.

Caspase-3 activity and the levels of DNA fragments of 200-600 and >4000 b.p. were estimated in the cerebellar vermis, the hippocampus, and the prefrontal cortex of the brains of adult rats four and 24 months after training to extinction of the acoustic startle reaction and conditioned fear. Differently timed changes in the levels of biochemical markers of apoptosis were seen to different extents in these brain areas after training. These changes were characterized by a decrease in caspase-3 activity in the cerebellar vermis and the hippocampus, with decreases in DNA fragmentation in the hippocampus and cerebral cortex and increases in measures of programmed cell death in the hypothalamus. These experimental data support the view that the apoptosis of cells in the mature brain is involved in the mechanisms of learning and memory.