Alzheimer’s disease is a progressive neurodegenerative disorder characterized by mitochondria dysfunction, accumulation of beta-amyloid plaques, and hyperphosphorylated tau tangles in the brain leading to memory loss and cognitive deficits. There is currently no cure for this condition, but the potential of stem cells for the therapy of neurodegenerative pathologies is actively being researched. This review discusses preclinical and clinical studies that have used mouse models and human patients to investigate the use of novel types of stem cell treatment approaches. The findings provide valuable insights into the applications of stem cell-based therapies and include the use of neural, glial, mesenchymal, embryonic, and induced pluripotent stem cells. We cover current studies on stem cell replacement therapy where cells can functionally integrate into neural networks, replace damaged neurons, and strengthen impaired synaptic circuits in the brain. We address the paracrine action of stem cells acting via secreted factors to induce neuroregeneration and modify inflammatory responses. We focus on the neuroprotective functions of exosomes as well as their neurogenic and synaptogenic effects. We look into the shuttling of mitochondria through tunneling nanotubes that enables the transfer of healthy mitochondria by restoring the normal functioning of damaged cells, improving their metabolism, and reducing the level of apoptosis.

Neurodegenerative diseases pose a significant challenge to modern medicine. Despite significant advances in neurology, current therapeutic approaches often prove insufficient to treat such disorders. This study investigates the neuroprotective effect of extracellular vesicles derived from glial derivates of human-induced pluripotent stem cells. The extracellular vesicle’s cargo was characterised by proteomic analysis. The neuroprotective effect was assessed using a model of glutamate excitotoxicity performed on a primary culture of cortical neuroglial cells. The viability of cells was estimated using the MTT test and morphometric analyses. A comprehensive methodology was applied to investigate intracellular mechanisms, integrating assessments of intracellular calcium concentrations, mitochondrial membrane potential, and targeted inhibition of the PI3K-Akt pathway. Transcriptomic analysis of neuroglial cultures was used to validate the role of obtained mechanisms of extracellular vesicle’s neuroprotective effect. The obtaining results demonstrated the improvement of neuronal survival by reducing intracellular calcium levels and stabilising mitochondrial membrane potential under glutamate-induced excitotoxicity via PI3K-Akt signalling pathway activation. Moreover, the vesicles contained proteins that contribute to preventing apoptotic processes, activating regeneration of the nervous system, and modulating calcium ion transport and are associated with redox processes. Further transcriptomic analyses of neuroglial cultures treated with EVs showed an up-regulation of genes associated with regeneration, inhibition of calcium ion transport, regulation of membrane depolarisation, and negative regulation of apoptotic pathways.

Relevance.The search for new methods of effective therapy for traumatic brain injury is one of the important tasks of modern biomedicine. One promising approach for treating traumatic brain injury is cell therapy. The aim of the work is to study the therapeutic effect of glial progenitor cells derived from induced pluripotent stromal cells in an experimental model of traumatic brain injury.Materials and Methods.Modeling of traumatic brain injury was carried out on mature male Wistar rats. The therapeutic group was administered asingle dose of 750*103cells/ml glial progenitor cells with avolume of 1 ml, and the control group — 1 ml of phosphate-­buffered saline. Administration was carried out intra-­arterially 24 hours after injury. To analyze the therapeutic effectiveness, an MRI study was performed on the 14th day, as well as alimb-placing test on the 1st, 3rd, 7th and 14th days. Histological examination was carried out on days 1, 3 and 7 after administration to assess the migration and distribution of stained cells (concentration 750*103cells/ml) by lipophilic dye PKH26 (Sigma, USA) at the rat’s brain tissues after traumatic brain injury. Measurements of injury volume and counts of PKH26-stained cells were performed using ImageJ software (Wayne Rasband, National Institute of Mental Health, Bethesda, MD, USA). The statistical analysis was carried out using GraphPad Prism 8.2.0 program (GraphPad Software, Inc., USA).Results and Discussion.Administration of GPCs led to decreasing the damage volume. Significant decrease in sensorimotor deficit was observed on days 3, 7 and 14 after injury compared with the control group. Intra-arterial administration resulted in successful delivery of glial progenitor cells to brain tissue. Cells were detected in the cerebral cortex, hippocampus, and striatum on day 1, and were not observed on days 3 and 7 after administration.Conclusion.Intra-arterial administration of GPCs leads to efficient migration of cells into brain tissue. Glial progenitor cells therapy promotes neurorecovery processes after traumatic brain injury. This therapy is apromising treatment for traumatic brain injury.

Neurodegenerative diseases pose a significant challenge to modern medicine. Despite significant advances in neurology, current therapeutic approaches often prove insufficient to treat such disorders. This study investigates the neuroprotective effect of extracellular vesicles derived from glial derivates of human induced pluripotent stem cells. The extra-cellular vesicle’s cargo was characterised by proteomic analysis. They neuroprotective ef-fect was assessed using a model of glutamate excitotoxicity performed on primary culture of cortical neurons. The viability of cortical neurons was estimated using the MTT test and morphometric analyses. A comprehensive methodology was applied to investigate intra-cellular mechanisms, integrating assessments of intracellular calcium concentrations, mitochondrial membrane potential, and targeted inhibition of the PI3K‑Akt pathway. Transcriptomic analysis of cortical neurons was used to validated the role of obtained mechanisms of extracellular vesicle’s neuroprotective effect. The obtaining results demon-strated the improvement of neuronal survival by reducing intracellular calcium levels, and stabilizing mitochondrial membrane potential under glutamate-induced excitotoxi-city via PI3K-Akt signaling pathway activation. Moreover, the vesicles contained proteins that contribute to preventing apoptotic processes, activating regeneration of nervous sys-tem, modulating of calcium ion transport and associated with redox processes. Further transcriptomic analyses of neuroglial cultures treated with EVs showed up-regulation of genes associated with regeneration, inhibition of calcium ion transport, regulation of membrane depolirisation and negative regulation of apoptotic pathways.

Relevance. Modern research in the field of biomedicine leads to the development of therapeutic drugs based on extracellular vesicles, which are defined as sources of production, as well as targeted modification. In the presented work, for the first time, transcriptome profiling of primary culture of cortical neurons under the influence of extracellular vesicles obtained from glial cells during glutamate excitotoxicity was carried out in order to determine differentially expressed genes. Materials and Methods. Extracellular vesicles were obtained from the conditioned medium of human glial progenitor cells using ultracentrifugation. Model of glutamate excitotoxicity, distributed on the first cultured cortical neurons of cells (P0) with the addition of 100 μM glutamate. Sequencing of prepared libraries of electronic technologies on the NextSeq 1000 platform (Illumina, USA) using the NextSeq 1000/2000 P2 (200 cycles) v3 reagent kit supplemented with 2 % Phix (Illumina) as an internal control. The criterion for statistical innovation of gene expression change between officially recognized FDR 0.05. Results and Discussion. Transcriptome analysis showed that the addition of extracellular vesicles during glutamate excitotoxicity leads to increased expression of 190 genes and decreased expression of 309 genes (p value 0.05 and |FC| 1.5). Gene analysis using the Gene Onthology database showed that genes with increased expression are consistently classified by biological processes. The most represented were: regeneration, reorganization of the extracellular matrix and cytoskeleton, maintenance of homeostasis, activation of the PI3K-Akt pathway and response to cellular stress. Genes with reduced expression were consistently classified into groups: calcium transport, regulation of neuronal processes, apoptosis, glutathergic synapse. These data can indicate that. Extracellular vesicles trigger survival processes in nerve cells when exposed to glutamate and inhibit pathways associated with the entry of substances and glutamate into the cell. Conclusions. Extracellular vesicles enhance the expression of genes with survival and inhibit genes, resulting in calcium transport and apoptosis. The results of the study show the promise of using extracellular vesicles of glial origin as a basis for developing new therapeutic approaches to individual neurological diseases.

Introduction: Traumatic brain injury presents a significant challenge, characterized by complex pathologies including neuroinflammation and axonal degeneration with limited treatment options. One of the promising areas of traumatic brain injury treatment is cell therapy. However, a critical aspect of this therapy is the method of stem/progenitor cell administration. This study aimed to evaluate the therapeutic potential of glial progenitor cells derived from induced pluripotent stem cells after intra-arterial administration in an experimental model of traumatic brain injury of male Wistar rats. Methods: Neurological status was assessed using the limb—placing, cylinder, and beam walking tests. Lesion volume was quantified by magnetic resonance imaging. Markers of inflammation and neurogenesis were analyzed using immunofluorescence staining and quantitative reverse transcription polymerase chain reaction. Cell migration was tracked via magnetic resonance imaging and histology. Results: Intra-arterial administration provided targeted delivery of cells into the cerebral vasculature. The cells successfully crossed the blood-brain barrier, migrated into the brain parenchyma, and were detectable for up to 48 hours. Transplantation led to significant improvement in sensorimotor function, reduced neuroinflammation in the injured area, and promoted neurogenesis. Discussion: The observed therapeutic effects are likely mediated by the factors secreted by glial progenitor cells, which possess anti-inflammatory and regenerative properties (paracrine signaling effect) and/or by their transient interactions with the target cells (juxtacrine signaling effect). Conclusion: Glial progenitor cells derived from induced pluripotent stem cells and delivered via the intra-arterial route show promise for the treatment of traumatic brain injury by reducing inflammation and enhancing neurogenesis.