A Mouse Model of Sporadic Alzheimer's Disease with Elements of Major Depression.

After olfactory bulbectomy, animals are often used as a model of major depression or sporadic Alzheimer's disease and, hence, the status of this model is still disputable. To elucidate the nature of alterations in the expression of the genome after the operation, we analyzed transcriptomes of the cortex, hippocampus, and cerebellum of the olfactory bulbectomized (OBX) mice. Analysis of the functional significance of genes in the brain of OBX mice indicates that the balance of the GABA/glutamatergic systems is disturbed with hyperactivation of the latter in the hippocampus, leading to the development of excitotoxicity and induction of apoptosis in the background of severe mitochondrial dysfunction and astrogliosis. On top of this, the synthesis of neurotrophic factors decreases leading to the disruption of the cytoskeleton of neurons, an increase in the level of intracellular calcium, and the activation of tau protein hyperphosphorylation. Moreover, the acetylcholinergic system is deficient in the background of the hyperactivation of acetylcholinesterase. Importantly, the activity of the dopaminergic, endorphin, and opiate systems in OBX mice decreases, leading to hormonal dysfunction. On the other hand, genes responsible for the regulation of circadian rhythms, cell migration, and innate immunity are activated in OBX animals. All this takes place in the background of a drastic downregulation of ribosomal protein genes in the brain. The obtained results indicate that OBX mice represent a model of Alzheimer's disease with elements of major depression.

The Balance between Two Branches of RAS Can Protect from Severe COVID-19 Course.

The COVID-19 pandemic has swept the world and required the mobilization of scientists and clinicians around the world to combat this serious disease. Along with SARS-CoV-2 virology research, understanding of the fundamental physiological processes, molecular and cellular mechanisms and intracellular signaling pathways underlying the clinical manifestations of COVID-19 is important for effective therapy of this disease. The review describes in detail the interaction of the components of the renin-angiotensin system (RAS) and receptors of end-glycosylated products (RAGE), which plays a special role in normal lung physiology and in pathological conditions in COVID-19, including the development of acute respiratory distress syndrome and "cytokine storm". A separate section is devoted to the latest developments aimed at correcting the dysfunction of the RAS caused by the binding of the virus to angiotensin converting enzyme 2 (ACE2)- the central element of this system. Analysis of published theoretical, clinical, and experimental data indicates the need for a complex treatment to prevent a severe course of COVID-19 using MasR agonists, blockers of the AT1R and NF-κB signaling pathway, as well as compounds with neuroprotective and neuroregenerative effects.

Effect of Intranasal Administration of Multipotent Mesenchymal Stromal Cell Exosomes on Memory of Mice in Alzheimer's Disease Model.

We studied the effect of intranasal administration of exosomes obtained by culturing of multipotent mesenchymal stromal cells (MMSC) isolated from the Wharton's jelly of the human umbilical cord on spatial memory of olfactory bulbectomized mice demonstrating the basic signs of a sporadic form of Alzheimer's disease. Intranasal administration of isolated exosomes expressing typical markers CD9, CD63 and CD81 improved spatial memory in bulbectomized animals, which manifested in a significant increase in the number of visits to the target sector and the time spent there in comparison with indifferent sectors. After administration, labeled exosomes were found in the hippocampus and neocortex, the structures playing an important role in learning and memory processes and affected by Alzheimer's disease. The advantages of exosomes in comparison with MMSC are their small size, low immunogenicity, and inability to cause cell transformation together with high therapeutic efficacy.

Effect of Transplantation of Neural Stem and Progenitor Cells on Memory in Animals with Alzheimer's Type Neurodegeneration.

The effects of systemic and intracerebral transplantation of human fetal neural stem and progenitor cells were studied on the model of olfactory bulbectomy in mice with developing signs of sporadic Alzheimer's disease. It was found that transplantation of these cells at certain stages of disease development contributed to improvement of spatial memory and preservation of hippocampal neurons in these animals.

Neuroregeneration: Regulation in Neurodegenerative Diseases and Aging.

It had been commonly believed for a long time, that once established, degeneration of the central nervous system (CNS) is irreparable, and that adult person merely cannot restore dead or injured neurons. The existence of stem cells (SCs) in the mature brain, an organ with minimal regenerative ability, had been ignored for many years. Currently accepted that specific structures of the adult brain contain neural SCs (NSCs) that can self-renew and generate terminally differentiated brain cells, including neurons and glia. However, their contribution to the regulation of brain activity and brain regeneration in natural aging and pathology is still a subject of ongoing studies. Since the 1970s, when Fuad Lechin suggested the existence of repair mechanisms in the brain, new exhilarating data from scientists around the world have expanded our knowledge on the mechanisms implicated in the generation of various cell phenotypes supporting the brain, regulation of brain activity by these newly generated cells, and participation of SCs in brain homeostasis and regeneration. The prospects of the SC research are truthfully infinite and hitherto challenging to forecast. Once researchers resolve the issues regarding SC expansion and maintenance, the implementation of the SC-based platform could help to treat tissues and organs impaired or damaged in many devastating human diseases. Over the past 10 years, the number of studies on SCs has increased exponentially, and we have already become witnesses of crucial discoveries in SC biology. Comprehension of the mechanisms of neurogenesis regulation is essential for the development of new therapeutic approaches for currently incurable neurodegenerative diseases and neuroblastomas. In this review, we present the latest achievements in this fast-moving field and discuss essential aspects of NSC biology, including SC regulation by hormones, neurotransmitters, and transcription factors, along with the achievements of genetic and chemical reprogramming for the safe use of SCs in vitro and in vivo.

Molecular and Cellular Mechanisms of Sporadic Alzheimer's Disease: Studies on Rodent Models in vivo.

In this review, recent data are presented on molecular and cellular mechanisms of pathogenesis of the most widespread (about 95%) sporadic forms of Alzheimer's disease obtained on in vivo rodent models. Although none of the available models can fully reproduce the human disease, several key molecular mechanisms (such as dysfunction of neurotransmitter systems, especially of the acetylcholinergic system, ß-amyloid toxicity, oxidative stress, neuroinflammation, mitochondrial dysfunction, disturbances in neurotrophic systems) are confirmed with different models. Injection models, olfactory bulbectomy, and senescence accelerated OXYS rats are reviewed in detail. These three approaches to in vivo modeling of sporadic Alzheimer's disease have demonstrated a considerable similarity in molecular and cellular mechanisms of pathology development. Studies on these models provide complementary data, and each model possesses its specific advantages. A general analysis of the data reported for the three models provides a multifaceted and the currently most complete molecular picture of sporadic Alzheimer's disease. This is highly relevant also from the practical viewpoint because it creates a basis for elaboration and preclinical studies of means for treatment of this disease.

Mitochondrial Dysfunction in Neocortex and Hippocampus of Olfactory Bulbectomized Mice, a Model of Alzheimer's Disease.

Structural and functional impairments of mitochondria in brain tissues in the pathogenesis of Alzheimer's disease (AD) cause energy deficiency, increased generation of reactive oxygen species (ROS), and premature neuronal death. However, the causal relations between accumulation of beta-amyloid (Aß) peptide in mitochondria and mitochondrial dysfunction, as well as molecular mechanisms underlying deleterious effects of both these factors in sporadic AD, the most common form in humans, remain unknown. Here we used olfactory bulbectomized (OBX) mice of NMRI strain as a model for sporadic AD. Five weeks after surgery, the OBX mice developed major behavioral and biochemical features of AD neurodegeneration, including spatial memory loss, increased brain levels of Aß, and energy deficiency. Mitochondria isolated from the neocortex and hippocampus of OBX mice displayed severe functional impairments, such as low NADH oxidation rate, reduced transmembrane potential, and decreased cytochrome c oxidase (complex IV) activity that correlated with high levels of soluble Aß1-40. Mitochondria from OBX mice showed increased contents of lipid peroxidation products, indicative of the development of oxidative stress. We found that neurodegeneration caused by olfactory bulbectomy is accompanied by energy metabolism disturbances and oxidative stress in brain mitochondria similar to those occurring in transgenic animals - familial AD models and patients with sporadic AD. Therefore, OBX mice can serve as a valid AD model for investigating the mechanisms of AD neurodegeneration, drug testing, and development of therapeutic strategies for AD treatment.

The Y-Box Binding Protein 1 Suppresses Alzheimer's Disease Progression in Two Animal Models.

The Y-box binding protein 1 (YB-1) is a member of the family of DNA- and RNA binding proteins. It is involved in a wide variety of DNA/RNA-dependent events including cell proliferation and differentiation, stress response, and malignant cell transformation. Previously, YB-1 was detected in neurons of the neocortex and hippocampus, but its precise role in the brain remains undefined. Here we show that subchronic intranasal injections of recombinant YB-1, as well as its fragment YB-11-219, suppress impairment of spatial memory in olfactory bulbectomized (OBX) mice with Alzheimer's type degeneration and improve learning in transgenic 5XFAD mice used as a model of cerebral amyloidosis. YB-1-treated OBX and 5XFAD mice showed a decreased level of brain ß-amyloid. In OBX animals, an improved morphological state of neurons was revealed in the neocortex and hippocampus; in 5XFAD mice, a delay in amyloid plaque progression was observed. Intranasally administered YB-1 penetrated into the brain and could enter neurons. In vitro co-incubation of YB-1 with monomeric ß-amyloid (1-42) inhibited formation of ß-amyloid fibrils, as confirmed by electron microscopy. This suggests that YB-1 interaction with ß-amyloid prevents formation of filaments that are responsible for neurotoxicity and neuronal death. Our data are the first evidence for a potential therapeutic benefit of YB-1 for treatment of Alzheimer's disease.

[Protective Activity of Prion Protein Fragments after Immunization of Annimals with Experimentally Induced Alzheimer's Disease].

The prion protein is considered as one of the membrane targets of neurotoxic beta-amyloid during Alzheimer's disease development. We have chosen and synthesized 17-33, 23-33, 95-110 and 101-115 prion fragments involved in beta-amyloid binding. The effect of immunization with the peptides on the features of Alzheimer's disease was investigated in animals with an experimentally induced form of the disease. It was shown that immunization either with peptide 17-33 or with protein conjugates of peptides 23-33 and 101-115 increases the level of brain beta-amyloid and improves morfofunctional state of the brain.

[Fragment of Receptor for Advanced Glycation End Products Improves Memory State in a Model of Alzheimer's Disease].

A number of synthetic peptides corresponding to potentially important regions in the sequence of the four membrane proteins known as beta-amyloid cell receptors have been investigated on their ability to improve memory state in experimental model of Alzheimer's disease. Nine fragments repeating all the exposed nonstructural regions of the RAGE protein according to X-ray data, have been synthesized. The activity of these peptides and synthesized earlier immunoprotective fragments of other three proteins (acetylcholine receptor alpha7-type, prion protein and neurotrophin receptor p75) has been investigated under intranasal administration, without immune response to the peptide. Only one fragment RAGE (60-76) was shown to have a therapeutic activity improving the memory state of bulbectomized mice and leads to decreasing in the level of brain beta-amyloid.

Beta-Amyloid and Tau-Protein: Structure, Interaction, and Prion-Like Properties.

During the last twenty years, molecular genetic investigations of Alzheimer's disease (AD) have significantly broadened our knowledge of basic mechanisms of this disorder. However, still no unambiguous concept on the molecular bases of AD pathogenesis has been elaborated, which significantly impedes the development of AD therapy. In this review, we analyze issues concerning processes of generation of two proteins (ß-amyloid peptide and Tau-protein) in the cell, which are believed to play the key role in AD genesis. Until recently, these agents were considered independently of each other, but in light of the latest studies, it becomes clear that it is necessary to study their interaction and combined effects. Studies of mechanisms of toxic action of these endogenous compounds, beginning from their interaction with known receptors of main neurotransmitters to specific peculiarities of functioning of signal intracellular pathways upon development of this pathology, open the way to development of new pharmaceutical substances directed concurrently on key mechanisms of interaction of toxic proteins inside the cell and on the pathways of their propagation in the extracellular space.

Localization and differentiation pattern of transplanted human multipotent mesenchymal stromal cells in the brain of bulbectomized mice.

Replacement cell therapy with transplantation of stem cells is a promising approach for the therapy of various neurodegenerative diseases, e.g. Alzheimer's disease. However, the behavior of transplanted cells in the damaged tissue should be thoroughly studied before introduction of this method into clinical practice. We studied the pathways of migration of human multipotent mesenchymal stromal cells after their systemic transplantation into the brain of bulbectomized mice characterized by the development of Alzheimer-type neurodegenerative process. Immunohistochemical analysis with antibodies to human nuclear antigen (HNA) and immunofluorescent analysis of the results of transplantation of multipotent mesenchymal stromal cells carrying green fluorescent protein (GFP) gene showed that these cells can cross the blood-brain barrier and penetrate into some structures of recipient brain. Analysis of differentiation of transplanted human cells using antibodies to neurospecific enolase (NSE) or astroglial marker (GFAP) with parallel staining for human nuclear antigen revealed no neural differentiation of transplanted cells in the brains of bulbectomized animals. However, some of these cells differentiated into astrocytes, which brought us to an assumption on important role of astroglial abnormalities in the pathogenesis of Alzheimer's disease.

[Mechanism of action of combined extremely weak magnetic field on aqueous solution of amino acid].

The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 µT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects.

Immunization with either prion protein fragment 95-123 or the fragment-specific antibodies rescue memory loss and neurodegenerative phenotype of neurons in olfactory bulbectomized mice.

Epidemiological studies demonstrated association between head injury (HI) and the subsequent development of Alzheimer's disease (AD). Certain hallmarks of AD, e.g. amyloid-ß (Aß) containing deposits, may be found in patients following traumatic BI (TBI). Recent studies uncover the cellular prion protein, PrP(C), as a receptor for soluble polymeric forms of Aß (sAß) which are an intermediate of such deposits. We aimed to test the hypothesis that targeting of PrP(C) can prevent Aß related spatial memory deficits in olfactory bulbectomized (OBX) mice utilized here to resemble some clinical features of AD, such as increased level of Aß, memory loss and deficit of the CNS cholin- and serotonin-ergic systems. We demonstrated that immunization with the a.a. 95-123 fragment of cellular prion (PrP-I) recovered cortical and hippocampus neurons from OBX induced degeneration, rescued spatial memory loss in Morris water maze test and significantly decrease the Aß level in brain tissue of these animals. Affinity purified anti-PrP-I antibodies rescued pre-synaptic biomarker synaptophysin eliciting similar effect on memory of OBX mice, and protected hippocampal neurones from Aß25-35-induced toxicity in vitro. Immunization OBX mice with a.a. 200-213 fragment of cellular prion (PrP-II) did not reach a significance in memory protection albeit having similar to PrP-I immunization impact on Aß level in brain tissue. The observed positive effect of targeting the PrP-I by either active or passive immunization on memory of OBX mice revealed the involvement of the PrP(C) in AD-like pathology induced by olfactory bulbectomy. This OBX model may be a useful tool for mechanistic and preclinical therapeutic investigations into the association between PrP(C) and AD.

[Immunization witha synthetic fragment 155-164 of neurotrophin receptor p75 prevents memory loss and decreases beta-amyloid level in mice with experimentally induced Alzheimer's disease].

Neurotoxic beta-amyloid peptide plays an important role in the pathology of Alzheimer's disease. In aggregated form it binds to several proteins on the surface of the brain cells leading to their death. p75 receptor in- volved in supporting of cell balance is one of the targets for toxic beta-amyloid. We proposed that induction of antibodies against potential binding sites of p75 with beta-amyloid can be a promising approach towards new drug development for Alzheimer's disease therapy. Four potentially immunoactive fragments of p75 were chosen and chemically synthesized. Investigation of immunoprotective effect of the peptide fragments carried out in mice with experimentally induced form of Alzheimer's disease helped to reveal two fragments effectively preserving murine memory from impairment. Results obtained by ELISA biochemical analysis showed that only immunization with fragment p75 155-164 led to significant decrease in beta-amyloid level in the brain of the experimental mice. Thus, immunization with both fragments of p75 receptor is believed to be an effective tool for the development of new drugs against Alzheimer's disease.

Therapeutic effect of mesenchymal multipotent stromal cells on memory in animals with Alzheimer-type neurodegeneration.

Transplantation of human mesenchymal multipotent stromal cells improved spatial memory in bulbectomized mice with Alzheimer-type neurodegeneration. The positive effect was observed in 1 month after intracerebral transplantation and in 3 months after systemic injection of mesenchymal multipotent stromal cells. No cases of malignant transformation were noted. These findings indicate prospects of using mesenchymal multipotent stromal cells for the therapy of Alzheimer disease and the possibility of their systemic administration for attaining the therapeutic effect.

Investigating the Icr Effect in a Zhadin's Cell.

Investigations into the ion cyclotronic resonance (ICR) in living matter confront the so called Zhadin effect (12), whose explanation is not fully achieved. Several attempts have been done to explain this phenomenon, the most interesting of which is based on Quantum Electrodynamics (18): the molecules of water, the ions and the biomolecules form extended mesoscopic regions, called Coherence Domains (CD), where they oscillate in unison between two selected levels of their spectra in tune with a self-produced coherent E.M. field having a well defined frequency, dynamically trapped within the CD. Moreover, it is possible, to induce, by an external applied field (either hydrodynamical or EM) or also by a chemical stimulation, coherent excitations of CD's that give rise to electric currents circulating without friction within the CD's: as a consequence magnetic fields are produced. A resonating magnetic field thus is able to extract the ions from the orbit and push them in the flowing current. Electrochemical investigation of the system suggested that the observed phenomenon involves the transitory activation of the anode due to ICR, followed by anode passivation due to the adsorption of amino acid and its oxidation products (18). This hypothesis induced us to investigate an alternate configuration of the experiment, removing the electrolytic cell and submitting a flask containing the solution into a condenser to be exposed to the proper ICR. Temperature and variable parameters involved in the effect have been investigated in order to overcome the randomness of the effect.

Morphofunctional state of neurons in the temporal cortex and hippocampus in relation to the level of spatial memory in rats after ablation of the olfactory bulbs.

Ablation of the olfactory bulbs (bulbectomy) in mice and guinea pigs evokes a neurodegenerative process which, in terms of its morphological, biochemical, and behavioral features, is similar to Alzheimer's disease. We report here studies of the long-term sequelae of bulbectomy in rats. One year after surgery, testing of spatial memory in bulbectomized rats (BER) allowed the animals to be divided into two groups-those with good memory (BER-gm) and those with poor memory (BER-pm). Quantitative analysis of the morphofunctional state of neurons showed that BER-pm, as compared with the BER-gm group, had more marked pathological lesions in neurons of the temporal cortex and hippocampus, with significant increases in the numbers of cells showing pyknosis, karyolysis, cytolysis, and vacuolization. Both groups showed decreases in the distribution density of cells in the cortex. In terms of the level of brain beta-amyloid, the study groups fell in the order: BER-pm>BER-gm>control sham-operated rats. These results provide evidence of the long-term nature of changes in the morphofunctional state of neurons in the brains of BER, correlating with their levels of spatial memory.

[New approaches to the immunotherapy of Alzheimer's disease with the synthetic fragments of alpha7 subunit of the acetylcholine receptor].

The effect of immunization with the synthetic fragments of the alpha7 subunit of the acetylcholine nicotine receptor on the spatial memory of mice subjected to olfactory bulbectomy, which causes the development of the neuro-degenetrative disease of Alzheimer's type, was studied. Mice of the NMRI line were immunized with the KLH conjugates of two peptide fragments of the N-terminal fragment of the alpha7 subunit extraxcellular fragment, subjected to olfactory bulbectomy to cause the development of the neurodegenetrative disease of Alzheimer's type, and then the state of the spartial memory was evaluated. It was shown that 20% of bulbectomized mice immunized with the N-terminal 1-23 fragment exhibited good spatial memory after training. Immunization with the peptide construct (159-167)-(179-188) consisting of two hydrophilic exposed regions of alpha7-subunit induced good spatial memory in 50% of bulbectomized mice, while in the control group, which received only KLH, none of the animals were educated. Thus, the development of immunotherapy with peptide (159-167)-(179-188) seems to be a promising approach to prophylaxis and treatment of Alzheimer's disease.