Evgeniy Svirin

Growing evidence suggests an important pathogenetic role of brain-specific gangliosides in the mechanisms underlying Alzheimer’s disease (AD), the most common form of dementia. Nutritional strategies targeting ganglioside sialylation—for example, through agglutinin-mediated modulation—have therefore attracted increasing research interest. In particular, wheat malt extract (WME), a food-derived source of wheat germ agglutinin (WGA) with high affinity for gangliosides, may influence molecular pathways involved in AD pathogenesis. Twelve-month-old female APPswe/PS1E9 transgenic mice, a model of AD, and wild-type (WT) littermates received WME or tap water for three weeks. Behavioral performance was subsequently assessed. Amyloid plaque burden and astrocyte activation were evaluated using Congo red staining and GFAP immunoreactivity, respectively. Gene expression of selected AD markers in the brain was quantified by RT–qPCR. Aged WT mice exhibited robust, region-specific molecular responses to WME, including upregulation of activity-dependent and synaptic plasticity genes (Arc, Egr1, Bdnf, Syp), enhancement of metabolic and insulin-related signaling (Pgc1a, Sirt1, Igf1r, Irs2), increased Cldn5 expression, and reduced pro-inflammatory Il1β expression. APP/PS1 mice exhibited limited response to WME, suggesting more persistent transcriptional signatures of synaptic impairment, metabolic dysregulation, and neuroinflammation than in WT mice. We found no significant effects of WME treatment on amyloid plaque density and behavior in APP/PS1 mice. No effects on astrocyte activation were observed in either group. These findings demonstrate that dietary WME counteracts abnormal behaviors and molecular changes in neuron plasticity, metabolic, and vascular markers under conditions of normal aging but fails to improve the hallmarks of AD pathology. This highlights the potential of WGA-containing nutrients as a preventive nutritional approach targeting pathogenic mechanisms of aging and, potentially, AD pathology.

Background/Objectives: Reduced serotonin transporter (SERT) function is associated with increased vulnerability to emotional and metabolic dysregulation, particularly in elderly women. Most preclinical studies relied on young male rodents with complete Sert deficiency; the Western diet (WD) acerbates these abnormalities. However, complete Sert loss does not fully reflect the human condition of partial SERT dysfunction. Here, we examined the effects of WD in aged female Sert^+/− mice on metabolic, biochemical, molecular, and behavioral outcomes. Methods: Wild-type (WT) and Sert^+/− mice were fed WD or a control diet. Emotionality, cognition, glucose tolerance (GT), plasma ¹HNMR spectroscopy metabolome and biochemical parameters were studied. Gene expression analyses of nitric oxide (NO)-related markers were performed in the hypothalamus, dorsal raphe, and liver. Results: WD-exposed WT mice showed impaired GT and reduced plasma lactate and branched-chain amino acid levels; metabolome changes were more pronounced in mutants, while GT was unchanged. Naïve Sert^+/− mice exhibited lower lactate and alanine levels compared with WT controls. WD increased leptin and cholesterol levels in both genotypes, whereas triglyceride concentrations were reduced in Sert^+/− mice. Both WD and Sert deficiency increased Nos expression, while arginase expression was differentially regulated by genotype and diet. Malondialdehyde levels were elevated in the prefrontal cortex of Sert^+/− mice regardless diet. WD also impaired object recognition memory and induced anxiety- and depression-like behaviors, with more pronounced effects in Sert^+/− mice, except marble test behavior. Conclusions: Partial Sert deficiency aggravates some but not all WD-induced metabolic alterations, enhances oxidative stress, dysregulates arginine–NO signaling, and modifies behavior, highlighting the translational relevance of Sert^+/− mice for modeling SERT dysfunction.

The study of molecular mechanisms underlying late-life depression (LLD) is increasingly important in light of population aging. To date, LLD-related molecular brain changes remain poorly understood. Furthermore, environmental factors such as climate change and geography contribute to LDD risks. One overlooked factor might be deuterium—a stable hydrogen isotope—whose concentration in drinking water can vary geographically (~90–155 ppm) and alter the incidence of mood disorders. Conversely, potential effects of natural variations in deuterium content in drinking water on LLD symptoms and brain gene expression remain unknown. We conducted Illumina gene expression profiling in the hippocampi and prefrontal cortexes of 18-month-old C57BL/6J mice, a model of LLD-like behaviors, compared to 3-month-old controls. Separately, aged mice were allowed to consume deuterium-depleted (DDW, ~90 ppm) or control (~140 ppm) water for 21 days and were studied for LLD-like behaviors and Illumina gene expression of the brain. Naïve old mice displayed ≥2-fold significant changes of 35 genes. Housing on DDW increased their hedonic sensitivity and novelty exploration, reduced helplessness, improved memory, and significantly altered brain expression of Egr1, Per2, Homer1, Gadd45a, and Prdx4, among others. These genes revealed significant alterations in several GO-BP and KEGG pathways implicated in inflammation, cellular stress, synaptic plasticity, emotionality, and regeneration. Additionally, we found that incubation of primary neuronal cultures in DDW-containing buffer ameliorated Ca²⁺ influx and mitochondrial potential in a toxicity model, suggesting the involvement of mitochondrial mechanisms in the effects of decreased deuterium levels. Thus, aging induced profound brain molecular changes that may at least in part contribute to LLD pathophysiology. Reduced deuterium intake exerted modest but significant effects on LLD-related behaviors in aged mice, which can be attributed to, but not limited by ameliorated mitochondrial function and changes in brain gene expression.

Neuroinflammation is a key feature of Alzheimer’s disease (AD), and stem cell therapies have emerged as promising candidates due to their immunomodulatory properties. Neuro-Cells (NC), a combination of unmodified mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs), have demonstrated therapeutic potential in models of central nervous system (CNS) injury and neurodegeneration. Here, we studied the effects of NC in APPswe/PS1dE9 mice, an AD mouse model. Twelve-month-old APPswe/PS1dE9 mice or their wild-type littermates were injected with NC or vehicle into the cisterna magna. Five to six weeks post-injection, cognitive, locomotor, and emotional behaviors were assessed. The brain was stained for amyloid plaque density using Congo red, and for astrogliosis using DAPI and GFAP staining. Gene expression of immune activation markers (Il-1β, Il-6, Cd45, Tnf) and plasticity markers (Tubβ3, Bace1, Trem2, Stat3) was examined in the prefrontal cortex. IL-6 secretion was measured in cultured human monocytes following endotoxin challenge and NC treatment. Untreated APPswe/PS1dE9 mice displayed impaired learning in the conditioned taste aversion test, reduced object exploration, and anxiety-like behavior, which were improved in the NC-treated mutants. NC treatment normalized the expression of several immune and plasticity markers and reduced the density of GFAP-positive cells in the hippocampus and thalamus. NC treatment decreased amyloid plaque density in the hippocampus and thalamus, targeting plaques of 2. Additionally, NC treatment suppressed IL-6 secretion by human monocytes. Thus, NC treatment alleviated behavioral deficits and reduced amyloid plaque formation in APPswe/PS1dE9 mice, likely via anti-inflammatory mechanisms. The reduction in IL-6 production in human monocytes further supports the potential of NC therapy for the treatment of AD.

Fullerenes and fullerenols exhibit antioxidant and anti-inflammatory properties, making them promising candidates for Alzheimer’s disease (AD) therapy. Unlike conventional anti-inflammatory drugs, these compounds have multitargeted effects, including their ability to inhibit amyloid fibril formation. However, few studies have explored their efficacy in high-validity AD models. Female APPswe/PS1E9 (APP/PS1) mice and their wild-type (WT) littermates were orally administered with fullerene C₆₀ (0.1 mg/kg/day) or fullerenol C₆₀(OH)₂₄ (0.15 mg/kg/day) for 10 months starting at 2 months of age. Behavioral assessments were performed at 12 months of age. Amyloid plaque density and size were analyzed in the brain regions using Congo red staining. The expression of genes related to inflammation and plasticity was examined, and an in vitro assay was used to test the toxicity of fullerenol and its effect on amyloid β peptide 42 (Aβ42)-induced reactive oxygen species (ROS) production. Fullerenol reduced the maximum plaque size in the cortex and hippocampus, decreased the small plaque density in the hippocampus and thalamus, and prevented an increase in glial fibrillary acidic protein (GFAP) positive cell density in the mutants. Both treatments improved cognitive and emotional behaviors and reduced Il1β and increased Sirt1 expression. In vitro, fullerenol was non-toxic across a range of concentrations and reduced Aβ42-induced ROS production in brain endothelial cells and astrocytes. Long-term administration of fullerene or fullerenol improved behavioral and molecular markers of AD in APP/PS1 mice, with fullerenol showing additional benefits in reducing amyloid burden.

Eye fixations are increasingly employed to control computers through gaze-sensitive interfaces, yet the brain mechanisms supporting this non-visual use of gaze remain poorly understood. In this study, we employed 306-channel magnetoencephalography (MEG) to find out what is specific to brain activity when gaze is used voluntarily for control. MEG was recorded while participants played a video game controlled by their eye movements. Each move required object selection by fixating it for at least 500 ms. Gaze dwells were classified as intentional if followed by a confirmation gaze on a designated location and as spontaneous otherwise. We identified both induced oscillatory and sustained phase-locked MEG activity differentiating intentional and spontaneous gaze dwells. Induced power analysis revealed prominent alpha-beta band synchronization (8–30 Hz) localized in the frontal cortex, with location broadly consistent with the frontal eye fields. This synchronization began 500–750 ms before intentional fixation onset and peaked shortly after it, suggesting proactive inhibition of saccadic activity. Sustained evoked responses further distinguished the two conditions, showing gradually rising cortical activation with a maximum at 200 ms post-onset in the inferior temporal cortex during intentional fixations, likely indicative of focused attentional engagement on spatial targets. These findings illuminate the neural dynamics underlying intentional gaze control, shedding light on the roles of proactive inhibitory mechanisms and attentional processes in voluntary behavior. By leveraging a naturalistic gaze-based interaction paradigm, this study offers a novel framework for investigating voluntary control under free behavior conditions and holds potential applications for enhancing hybrid eye-brain-computer interfaces.

The role of altered brain mitochondrial regulation in psychiatric pathologies, including Major Depressive Disorder (MDD), has attracted increasing attention. Aberrant mitochondrial functions were suggested to underlie distinct inter-individual vulnerability to stress-related MDD syndrome. In this context, insulin receptor sensitizers (IRSs) that regulate brain metabolism have become a focus of recent research, as their use in pre-clinical studies can help to elucidate the role of mitochondrial dynamics in this disorder and contribute to the development of new antidepressant treatment. Here, following 2-week chronic mild stress (CMS) using predation, social defeat, and restraint, MDD-related behaviour and brain molecular markers have been investigated along with the hippocampus-dependent performance and emotionality in mice that received the IRS dicholine succinate (DS). In a sucrose test, mice were studied for the key feature of MDD, a decreased sensitivity to reward, called anhedonia. Based on this test, animals were assigned to anhedonic and resilient-to-stress-induced-anhedonia groups, using a previously established criterion of a decrease in sucrose preference below 65%. Such assignment was based on the fact that none of control, non-stressed animals displayed sucrose preference that would be smaller than this value. DS-treated stressed mice displayed ameliorated behaviours in a battery of assays: sucrose preference, coat state, the Y-maze, the marble test, tail suspension, and nest building. CMS-vulnerable mice exhibited overexpression of the inflammatory markers Il-1β, tnf, and Cox-1, as well as 5-htt and 5-ht2a-R, in various brain regions. The alterations in hippocampal gene expression were the closest to clinical findings and were studied further. DS-treated, stressed mice showed normalised hippocampal expression of the plasticity markers Camk4, Camk2, Pka, Adcy1, Creb-ar, Nmda-2r-ar, and Nmda-2r-s. DS-treated and non-treated stressed mice who were resilient or vulnerable to anhedonia were compared for hippocampal mitochondrial pathway regulation using Illumina profiling. Resilient mice revealed overexpression of the mitochondrial complexes NADH dehydrogenase, succinate dehydrogenase, cytochrome bc1, cytochrome c oxidase, F-type and V-type ATPases, and inorganic pyrophosphatase, which were decreased in anhedonic mice. DS partially normalised the expression of both ATPases. We conclude that hippocampal reduction in ATP synthesis is associated with anhedonia and pro-inflammatory brain changes that are ameliorated by DS.

Aggression and deficient cognitive control problems are widespread in psychiatric disorders, including major depressive disorder (MDD). These abnormalities are known to contribute significantly to the accompanying functional impairment and the global burden of disease. Progress in the development of targeted treatments of excessive aggression and accompanying symptoms has been limited, and there exists a major unmet need to develop more efficacious treatments for depressed patients. Due to the complex nature and the clinical heterogeneity of MDD and the lack of precise knowledge regarding its pathophysiology, effective management is challenging. Nonetheless, the aetiology and pathophysiology of MDD has been the subject of extensive research and there is a vast body of the latest literature that points to new mechanisms for this disorder. Here, we overview the key mechanisms, which include neuroinflammation, oxidative stress, insulin receptor signalling and abnormal myelination. We discuss the hypotheses that have been proposed to unify these processes, as many of these pathways are integrated for the neurobiology of MDD. We also describe the current translational approaches in modelling depression, including the recent advances in stress models of MDD, and emerging novel therapies, including novel approaches to management of excessive aggression, such as anti-diabetic drugs, antioxidant treatment and herbal compositions.