Salivary oxytocin in autistic patients and in patients with intellectual disability

BACKGROUND

Assessing the role of oxytocin (OT) in the regulation of social interaction is a promising area that opens up new opportunities for studying the mechanisms of developing autism spectrum disorders (ASD).

AIM

To assess the correlation between the salivary OT level and age-related and psychopathological symptoms of children with intellectual disability (ID) and ASD.

METHODS

We used the clinical and psychopathological method to assess the signs of ASD based on International Classification of Diseases (ICD-10), the severity of ASD was specified by the selected Russian type version "Childhood Autism Rating Scale" (CARS). Patients of both groups had an IQ score below 70 points.

RESULTS

The median and interquartile range of salivary OT levels in patients with ID and ASD were 23.897 [14.260-59.643] pg/mL, and in the group ID without ASD - Me = 50.896 [33.502-83.774] pg/mL (p = 0.001). The severity of ASD on the CARS scale Me = 51.5 [40.75-56.0] score in the group ID with ASD, and in the group ID without ASD-at the level of Me = 32 [27.0-38.0] points (p < 0.001). According to the results of correlation-regression analysis in the main group, a direct correlation was established between salivary OT level and a high degree of severity of ASD Rho = 0.435 (p = 0.005). There was no correlation between the salivary OT level and intellectual development in the group ID with ASD, Rho = 0.013 (p = 0.941) and we have found a relationship between oxytocin and intellectual development in the group ID without ASD, Rho = 0.297 (p = 0.005). There was no correlation between salivary OT and age, ASD and age.

CONCLUSION

The results of this study indicate that patients in the group ID with ASD demonstrated a lower level of salivary OT concentration and a direct relationship between the maximum values of this indicator and the severity of autistic disorders, in contrast to patients in the group ID without ASD.

NLRP3 Inflammasome Blocking as a Potential Treatment of Central Insulin Resistance in Early-Stage Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a devastating neurodegenerative disorder. In recent years, attention of researchers has increasingly been focused on studying the role of brain insulin resistance (BIR) in the AD pathogenesis. Neuroinflammation makes a significant contribution to the BIR due to the activation of NLRP3 inflammasome. This study was devoted to the understanding of the potential therapeutic roles of the NLRP3 inflammasome in neurodegeneration occurring concomitant with BIR and its contribution to the progression of emotional disorders.

METHODS

To test the impact of innate immune signaling on the changes induced by Aβ1-42 injection, we analyzed animals carrying a genetic deletion of the Nlrp3 gene. Thus, we studied the role of NLRP3 inflammasomes in health and neurodegeneration in maintaining brain insulin signaling using behavioral, electrophysiological approaches, immunohistochemistry, ELISA and real-time PCR.

RESULTS

We revealed that NLRP3 inflammasomes are required for insulin-dependent glucose transport in the brain and memory consolidation. Conclusions NLRP3 knockout protects mice against the development of BIR: Taken together, our data reveal the protective role of Nlrp3 deletion in the regulation of fear memory and the development of Aβ-induced insulin resistance, providing a novel target for the clinical treatment of this disorder.

Blood-Brain Barrier Breakdown in Stress and Neurodegeneration: Biochemical Mechanisms and New Models for Translational Research

Blood-brain barrier (BBB) is a structural and functional element of the neurovascular unit (NVU), which includes cells of neuronal, glial, and endothelial nature. The main functions of NVU include maintenance of the control of metabolism and chemical homeostasis in the brain tissue, ensuring adequate blood flow in active regions, regulation of neuroplasticity processes, which is realized through intercellular interactions under normal conditions, under stress, in neurodegeneration, neuroinfection, and neurodevelopmental diseases. Current versions of the BBB and NVU models, static and dynamic, have significantly expanded research capabilities, but a number of issues remain unresolved, in particular, personification of the models for a patient. In addition, application of both static and dynamic models has an important problem associated with the difficulty in reproducing pathophysiological mechanisms responsible for the damage of the structural and functional integrity of the barrier in the diseases of the central nervous system. More knowledge on the cellular and molecular mechanisms of BBB and NVU damage in pathology is required to solve this problem. This review discusses current state of the cellular and molecular mechanisms that control BBB permeability, pathobiochemical mechanisms and manifestations of BBB breakdown in stress and neurodegenerative diseases, as well as the problems and prospects of creating in vitro BBB and NVU models for translational studies in neurology and neuropharmacology. Deciphering BBB (patho)physiology will open up new opportunities for further development in the related areas of medicine such as regenerative medicine, neuropharmacology, and neurorehabilitation.

Blood-Brain Barrier and Neurovascular Unit In Vitro Models for Studying Mitochondria-Driven Molecular Mechanisms of Neurodegeneration

Pathophysiology of chronic neurodegeneration is mainly based on complex mechanisms related to aberrant signal transduction, excitation/inhibition imbalance, excitotoxicity, synaptic dysfunction, oxidative stress, proteotoxicity and protein misfolding, local insulin resistance and metabolic dysfunction, excessive cell death, development of glia-supported neuroinflammation, and failure of neurogenesis. These mechanisms tightly associate with dramatic alterations in the structure and activity of the neurovascular unit (NVU) and the blood-brain barrier (BBB). NVU is an ensemble of brain cells (brain microvessel endothelial cells (BMECs), astrocytes, pericytes, neurons, and microglia) serving for the adjustment of cell-to-cell interactions, metabolic coupling, local microcirculation, and neuronal excitability to the actual needs of the brain. The part of the NVU known as a BBB controls selective access of endogenous and exogenous molecules to the brain tissue and efflux of metabolites to the blood, thereby providing maintenance of brain chemical homeostasis critical for efficient signal transduction and brain plasticity. In Alzheimer's disease, mitochondria are the target organelles for amyloid-induced neurodegeneration and alterations in NVU metabolic coupling or BBB breakdown. In this review we discuss understandings on mitochondria-driven NVU and BBB dysfunction, and how it might be studied in current and prospective NVU/BBB in vitro models for finding new approaches for the efficient pharmacotherapy of Alzheimer's disease.

NLRP3 deficiency-induced hippocampal dysfunction and anxiety-like behavior in mice

Neuroinflammation has been classified as a trigger of behavioral alterations and cognitive impairments in many neurological conditions, including Alzheimer's disease, major depression, anxiety and others. Regardless of the cause of neuroinflammation, key molecules, which sense neuropathological conditions, are intracellular multiprotein signaling inflammasomes. Increasing evidence shows that the inflammatory response, mediated by activated nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3) inflammasomes, is associated with the onset and progression of a wide range of diseases of the CNS. However, whether the NLRP3 inflammasome in the CNS is involved in the learning, development of anxiety and adult neurogenesis remains elusive. Therefore, the present study was designed to assess NLRP3 inflammasome contribution in anxiety and reveal its potential involvement in the experimental acquisition of fear responses and hippocampal neurogenesis. Behavioral, immunohistochemical and electrophysiological alterations were measured to evaluate role of neuroinflammation in the limbic system of mice. In this study, we describe interrelated neurophysiological mechanisms, which culminate in absence of NLRP3 inflammasome in young 4 months mice. These include the following: anxious behavior and deterioration in learning and memory of fear conditioning; impairment of adult neurogenesis; reduction and altered morphology of astrocytes in the brain; hyperexcitability in basolateral amygdala (BLA); impaired activation in axons of pyramidal cells of CA1 hippocampal zone in NLRP3 KO mice particularly via the Schaffer collateral pathway; and impaired synaptic transduction in pyramidal cells mediated by an embarrassment of neurotransmitter release from presynaptic site in CA3 hippocampal zone. The present study has demonstrated the novel findings that basal level of NLRP3 inflammasome in the brain of young mice is required for conditioning-induced plasticity in the ventral hippocampus and the basolateral amygdala. The deletion of NLRP3 impair synaptic transduction and caused anxiety-like behavior and labored fear learning, suggesting that low grade inflammation, mediated by NLRP3 expression, play a key role in memory consolidation.

Expression of NLRP3 Inflammasomes in Neurogenic Niche Contributes to the Effect of Spatial Learning in Physiological Conditions but Not in Alzheimer's Type Neurodegeneration

A common feature of neurodegenerative disorders, in particular Alzheimer's disease (AD), is a chronic neuroinflammation associated with aberrant neuroplasticity. Development of neuroinflammation affects efficacy of stem and progenitor cells proliferation, differentiation, migration, and integration of newborn cells into neural circuitry. However, precise mechanisms of neurogenesis alterations in neuroinflammation are not clear yet. It is well established that expression of NLRP3 inflammasomes in glial cells marks neuroinflammatory events, but less is known about contribution of NLRP3 to deregulation of neurogenesis within neurogenic niches and whether neural stem cells (NSCs), neural progenitor cells (NPCs) or immature neuroblasts may express inflammasomes in (patho)physiological conditions. Thus, we studied alterations of neurogenesis in rats with the AD model (intra-hippocampal injection of Aβ1-42). We found that in Aβ-affected brain, number of CD133+ cells was elevated after spatial training in the Morris water maze. The number of PSA-NCAM+ neuroblasts diminished by Aβ injection was completely restored by subsequent spatial learning. Spatial training leads to elevated expression of NLRP3 inflammasomes in the SGZ (subgranular zones): CD133+ and PSA-NCAM+ cells started to express NLRP3 in sham-operated, but not AD rats. Taken together, our data suggest that expression of NLRP3 inflammasomes in CD133+ and PSA-NCAM+ cells may contribute to stimulation of adult neurogenesis in physiological conditions, whereas Alzheimer's type neurodegeneration abolishes stimuli-induced overexpression of NLRP3 within the SGZ neurogenic niche.

Early life stress and brain plasticity: from molecular alterations to aberrant memory and behavior

Early life stress (ELS) is one of the most critical factors that could modify brain plasticity, memory and learning abilities, behavioral reactions, and emotional response in adulthood leading to development of different mental disorders. Prenatal and early postnatal periods appear to be the most sensitive periods of brain development in mammals, thereby action of various factors at these stages of brain development might result in neurodegeneration, memory impairment, and mood disorders at later periods of life. Deciphering the processes underlying aberrant neurogenesis, synaptogenesis, and cerebral angiogenesis as well as deeper understanding the effects of ELS on brain development will provide novel approaches to prevent or to cure psychiatric and neurological deficits caused by stressful conditions at the earliest stages of ontogenesis. Neuropeptide oxytocin serves as an amnesic, anti-stress, pro-angiogenic, and neurogenesis-controlling molecule contributing to dramatic changes in brain plasticity in ELS. In the current review, we summarize recent data on molecular mechanisms of ELS-driven changes in brain plasticity with the particular focus on oxytocin-mediated effects on neurogenesis and angiogenesis, memory establishment, and forgetting.

CD157 and Brain Immune System in (Patho)physiological Conditions: Focus on Brain Plasticity

Ectoenzyme and receptor BST-1/CD157 has been considered as a key molecule involved in the regulation of functional activity of cells in various tissues and organs. It is commonly accepted that CD157 catalyzes NAD+ hydrolysis and acts as a component of integrin adhesion receptor complex. Such properties are important for the regulatory role of CD157 in neuronal and glial cells: in addition to recently discovered role in the regulation of emotions, motor functions, and social behavior, CD157 might serve as an important component of innate immune reactions in the central nervous system. Activation of innate immune system in the brain occurs in response to infectious agents as well as in brain injury and neurodegeneration. As an example, in microglial cells, association of CD157 with CD11b/CD18 complex drives reactive gliosis and neuroinflammation evident in brain ischemia, chronic neurodegeneration, and aging. There are various non-substrate ligands of CD157 belonging to the family of extracellular matrix proteins (fibronectin, collagen I, finbrinogen, and laminin) whose activity is required for controlling cell adhesion and migration. Therefore, CD157 could control structural and functional integrity of the blood-brain barrier and barriergenesis. On the other hand, contribution of CD157 to the regulation of brain development is rather possible since in the embryonic brain, CD157 expression is very high, whereas in the adult brain, CD157 is expressed on neural stem cells and, presumably, is involved in the neurogenesis. Besides, CD157 could mediate astrocytes' action on neural stem and progenitor cells within neurogenic niches. In this review we will summarize how CD157 may affect brain plasticity acting as a molecule at the crossroad of neurogenesis, cerebral angiogenesis, and immune regulation.

Current approaches to modeling the virtual reality in rodents for the assessment of brain plasticity and behavior

Virtual reality (VR) and augmented reality (AR) have become valuable tools to study brains and behaviors resulting in development of new methods of diagnostics and treatment. Neurodegenerаtion is one of the best examples demonstrating efficacy of VR/АR technologies in modern neurology. Development of novel VR systems for rodents and combination of VR tools with up-to-date imaging techniques (i.e. MRI, imaging of neural networks etc.), brain electrophysiology (EEG, patch-clamp), precise analytics (microdialysis) allowed implementing of VR protocols into the animal neurobiology to study brain plasticity, sensorimotor integration, spatial navigation, memory, and decision-making. VR/AR for rodents is а young field of experimental neuroscience and has already provided more consistent testing conditions, less human-animal interaction, opportunities to use a wider variety of experimental parameters. Here we discuss present and future perspectives of using VR/AR to assess brain plasticity, neurogenesis and complex behavior in rodent and human study, and their advantages for translational neuroscience.

Pericytes in Alzheimer's Disease: Novel Clues to Cerebral Amyloid Angiopathy Pathogenesis

Pericytes in the central nervous system attract growing attention of neurobiologists because of obvious opportunities to use them as target cells in numerous brain diseases. Functional activity of pericytes includes control of integrity of the endothelial cell layer, regeneration of vascular cells, and regulation of microcirculation. Pericytes are well integrated in the so-called neurovascular unit (NVU) serving as a platform for effective communications of neurons, astrocytes, endothelial cells, and pericytes. Contribution of pericytes to the establishment and maintaining the structural and functional integrity of blood-brain barrier is confirmed in numerous experimental and clinical studies. The review covers current understandings on the role of pericytes in molecular pathogenesis of NVU/BBB dysfunction in Alzheimer's disease with the special focus on the development of cerebral amyloid angiopathy, deregulation of cerebral angiogenesis, and progression of BBB breakdown seen in Alzheimer's type neurodegeneration.

Oxytocin and excitation/inhibition balance in social recognition

Social recognition is the sensitive domains of complex behavior critical for identification, interpretation and storage of socially meaningful information. Social recognition develops throughout childhood and adolescent, and is affected in a wide variety of psychiatric disorders. Recently, new data appeared on the molecular mechanisms of these processes, particularly, the excitatory-inhibitory (E/I) ratio which is modified during development, and then E/I balance is established in the adult brain. While E/I imbalance has been proposed as a mechanism for schizophrenia, it also seems to be the common mechanism in autism spectrum disorder (ASD). In addition, there is a strong suggestion that the oxytocinergic system is related to GABA-mediated E/I control in the context of brain socialization. In this review, we attempt to summarize the underpinning molecular mechanisms of E/I balance and its imbalance, and related biomarkers in the brain in healthiness and pathology. In addition, because there are increasing interest on oxytocin in the social neuroscience field, we will pay intensive attention to the role of oxytocin in maintaining E/I balance from the viewpoint of its effects on improving social impairment in psychiatric diseases, especially in ASD.

Plasticity of Adipose Tissue-Derived Stem Cells and Regulation of Angiogenesis

Adipose tissue is recognized as an important organ with metabolic, regulatory, and plastic roles. Adipose tissue-derived stem cells (ASCs) with self-renewal properties localize in the stromal vascular fraction (SVF) being present in a vascular niche, thereby, contributing to local regulation of angiogenesis and vessel remodeling. In the past decades, ASCs have attracted much attention from biologists and bioengineers, particularly, because of their multilineage differentiation potential, strong proliferation, and migration abilities in vitro and high resistance to oxidative stress and senescence. Current data suggest that the SVF serves as an important source of endothelial progenitors, endothelial cells, and pericytes, thereby, contributing to vessel remodeling and growth. In addition, ASCs demonstrate intriguing metabolic and interlineage plasticity, which makes them good candidates for creating regenerative therapeutic protocols, in vitro tissue models and microphysiological systems, and tissue-on-chip devices for diagnostic and regeneration-supporting purposes. This review covers recent achievements in understanding the metabolic activity within the SVF niches (lactate and NAD+ metabolism), which is critical for maintaining the pool of ASCs, and discloses their pro-angiogenic potential, particularly, in the complex therapy of cardiovascular and cerebrovascular diseases.

Neurobiological Aspects of Face Recognition: The Role of Oxytocin

Face recognition is an important index in the formation of social cognition and neurodevelopment in humans. Changes in face perception and memory are connected with altered sociability, which is a symptom of numerous brain conditions including autism spectrum disorder (ASD). Various brain regions and neuropeptides are implicated in face processing. The neuropeptide oxytocin (OT) plays an important role in various social behaviors, including face and emotion recognition. Nasal OT administration is a promising new therapy that can address social cognition deficits in individuals with ASD. New instrumental neurotechnologies enable the assessment of brain region activation during specific social tasks and therapies, and can characterize the involvement of genes and peptides in impaired neurodevelopment. The present review sought to discuss some of the mechanisms of the face distinguishing process, the ability of OT to modulate social cognition, as well as new perspectives and technologies for research and rehabilitation of face recognition.

Designing in vitro Blood-Brain Barrier Models Reproducing Alterations in Brain Aging

Blood-brain barrier (BBB) modeling in vitro is a huge area of research covering study of intercellular communications and development of BBB, establishment of specific properties that provide controlled permeability of the barrier. Current approaches in designing new BBB models include development of new (bio) scaffolds supporting barriergenesis/angiogenesis and BBB integrity; use of methods enabling modulation of BBB permeability; application of modern analytical techniques for screening the transfer of metabolites, bio-macromolecules, selected drug candidates and drug delivery systems; establishment of 3D models; application of microfluidic technologies; reconstruction of microphysiological systems with the barrier constituents. Acceptance of idea that BBB in vitro models should resemble real functional activity of the barrier in different periods of ontogenesis and in different (patho) physiological conditions leads to proposal that establishment of BBB in vitro model with alterations specific for aging brain is one of current challenges in neurosciences and bioengineering. Vascular dysfunction in the aging brain often associates with leaky BBB, alterations in perivascular microenvironment, neuroinflammation, perturbed neuronal and astroglial activity within the neurovascular unit, impairments in neurogenic niches where microvascular scaffold plays a key regulatory role. The review article is focused on aging-related alterations in BBB and current approaches to development of “aging” BBB models in vitro.

Blood-brain barrier-supported neurogenesis in healthy and diseased brain

Adult neurogenesis is one of the most important mechanisms contributing to brain development, learning, and memory. Alterations in neurogenesis underlie a wide spectrum of brain diseases. Neurogenesis takes place in highly specialized neurogenic niches. The concept of neurogenic niches is becoming widely accepted due to growing evidence of the important role of the microenvironment established in the close vicinity to stem cells in order to provide adequate control of cell proliferation, differentiation, and apoptosis. Neurogenic niches represent the platform for tight integration of neurogenesis and angiogenesis supported by specific properties of cerebral microvessel endothelial cells contributing to establishment of partially compromised blood-brain barrier (BBB) for the adjustment of local conditions to the current metabolic needs of stem and progenitor cells. Here, we review up-to-date data on microvascular dynamics in activity-dependent neurogenesis, specific properties of BBB in neurogenic niches, endothelial-driven mechanisms of clonogenic activity, and future perspectives for reconstructing the neurogenic niches in vitro.

Differential Roles of Environmental Enrichment in Alzheimer's Type of Neurodegeneration and Physiological Aging

Impairment of hippocampal adult neurogenesis in aging or degenerating brain is a well-known phenomenon caused by the shortage of brain stem cell pool, alterations in the local microenvironment within the neurogenic niches, or deregulation of stem cell development. Environmental enrichment (EE) has been proposed as a potent tool to restore brain functions, to prevent aging-associated neurodegeneration, and to cure neuronal deficits seen in neurodevelopmental and neurodegenerative disorders. Here, we report our data on the effects of environmental enrichment on hippocampal neurogenesis in vivo and neurosphere-forming capacity of hippocampal stem/progenitor cells in vitro. Two models - Alzheimer's type of neurodegeneration and physiological brain aging - were chosen for the comparative analysis of EE effects. We found that environmental enrichment greatly affects the expression of markers specific for stem cells, progenitor cells and differentiated neurons (Pax6, Ngn2, NeuroD1, NeuN) in the hippocampus of young adult rats or rats with Alzheimer's disease (AD) model but less efficiently in aged animals. Application of time-lag mathematical model for the analysis of impedance traces obtained in real-time monitoring of cell proliferation in vitro revealed that EE could restore neurosphere-forming capacity of hippocampal stem/progenitor cells more efficiently in young adult animals (fourfold greater in the control group comparing to the AD model group) but not in the aged rats (no positive effect of environmental enrichment at all). In accordance with the results obtained in vivo, EE was almost ineffective in the recovery of hippocampal neurogenic reserve in vitro in aged, but not in amyloid-treated or young adult, rats. Therefore, EE-based neuroprotective strategies effective in Aβ-affected brain could not be directly extrapolated to aged brain.

Communication Impairment in Ultrasonic Vocal Repertoire during the Suckling Period of Cd157 Knockout Mice: Transient Improvement by Oxytocin

Communication consists of social interaction, recognition, and information transmission. Communication ability is the most affected component in children with autism spectrum disorder (ASD). Recently, we reported that the CD157/BST1 gene is associated with ASD, and that CD157 knockout (Cd157^−/−) mice display severe impairments in social behavior that are improved by oxytocin (OXT) treatment. Here, we sought to determine whether Cd157^−/− mice can be used as a suitable model for communication deficits by measuring ultrasonic vocalizations (USVs), especially in the early developmental stage. Call number produced in pups due to isolation from dams was higher at postnatal day (PND) 3 in knockout pups than wild-type mice, but was lower at PNDs 7 and 10. Pups of both genotypes had similarly limited voice repertoires at PND 3. Later on, at PNDs 7 and 10, while wild-type pups emitted USVs consisting of six different syllable types, knockout pups vocalized with only two types. This developmental impairment in USV emission was rescued within 30 min by intraperitoneal OXT treatment, but quickly returned to control levels after 120 min, showing a transient effect of OXT. USV impairment was partially observed in Cd157^+/− heterozygous mice, but not in Cd157^−/− adult male mice examined while under courtship. These results demonstrate that CD157 gene deletion results in social communication insufficiencies, and suggests that CD157 is likely involved in acoustic communication. This unique OXT-sensitive developmental delay in Cd157^−/− pups may be a useful model of communicative interaction impairment in ASD.

[The battery of tests for behavioral phenotyping of aging animals in the experiment]

The purpose of the study was to develop a battery of tests to study social and cognitive impairments for behavioral phenotyping of aging experimental animals with physiological neurodegeneration. Object of the study were outbred CD1 mice in the following groups: 1st group - 12-month old male mice (physiological aging); 2nd group - 2-month old male mice (control group). Social recognition test, elevated plus maze test (EPM), open field test, light-dark box test, and Fear conditioning protocol were used to estimate the neurological status of experimental animals. We found that aging male mice in a contrast to young ones have demonstrated lower social interest to female mice in the social recognition task. EPM and light-dark box tests showed increased level of anxiety in the group of aged mice comparing to the control group. Fear conditioning protocol revealed impairment of associative learning and memory in the group of aged mice, particularly, fear memory consolidation was dramatically suppressed. Analysis of behavioral factors, social interactions and anxiety level in the experimental mice has confirmed age-related neurodegeneration in the 1st group. We found that the most informative approach to identifying neurological impairments in aging mice (social interaction deficit, limitation of interests, increased level of anxiety) should be based on the open field test light-dark box test, and Fear conditioning protocol. Such combination allows obtaining new data on behavioral alterations in the age-associated of neurodegeneration and to develop novel therapeutic strategies for the treatment of age-related brain pathology.

Astroglial control of neuroinflammation: TLR3-mediated dsRNA-sensing pathways are in the focus

Neuroinflammation is as an important component of pathogenesis in many types of brain pathology. Immune mechanisms regulate neuroplasticity, memory formation, neurogenesis, behavior, brain development, cognitive functions, and brain metabolism. It is generally believed that essential homeostatic functions of astrocytes - astroglia-neuron metabolic coupling, gliovascular control, regulation of proliferation, and migration of cells in the neurogenic niches - are compromised in neuroinflammation resulting in excitotoxicity, neuronal and glial cell death, and alterations of intercellular communication. Viral neuroinfection, release of non-coding RNAs from the cells at the sites of brain injury or degeneration, and application of siRNA or RNA aptamers as therapeutic agents would require dsRNA-sensing pathways in the cells of neuronal and non-neuronal origin. In this review, we analyze the data regarding the role of astrocytes in dsRNA-initiated innate immune response in neuroinflammation and their contribution to progression of neurodegenerative and neurodevelopmental pathology.

Current advances in cell electrophysiology: applications for the analysis of intercellular communications within the neurovascular unit

Patch clamp is a golden standard for studying (patho)physiological processes affecting membranes of excitable cells. This method is rather labor-intensive and requires well-trained professionals and long-lasting experimental procedures; therefore, accurate designing of the experiments with patch clamp methodology as well as collecting and analyzing the data obtained are essential for the widely spread implementation of this method into the routine research practice. Recently, the method became very prospective not only for the characterization of single excitable cells but also for the detailed assessment of intercellular communication, i.e. within the neurovascular unit. Here, we analyze the main advantages and disadvantages of patch clamp method, with special focus on the tendencies in clamping technique improvement with the help of patch electrodes for the assessment of intercellular communication in the brain.

H2S- and NO-Signaling Pathways in Alzheimer's Amyloid Vasculopathy: Synergism or Antagonism?

Alzheimer's type of neurodegeneration dramatically affects H2S and NO synthesis and interactions in the brain, which results in dysregulated vasomotor function, brain tissue hypoperfusion and hypoxia, development of perivascular inflammation, promotion of Aβ deposition, and impairment of neurogenesis/angiogenesis. H2S- and NO-signaling pathways have been described to offer protection against Alzheimer's amyloid vasculopathy and neurodegeneration. This review describes recent developments of the increasing relevance of H2S and NO in Alzheimer's disease (AD). More studies are however needed to fully determine their potential use as therapeutic targets in Alzheimer's and other forms of vascular dementia.

In Vitro Modeling of Brain Progenitor Cell Development under the Effect of Environmental Factors

We studied in vitro development of brain progenitor cells isolated from healthy 7-9-month-old Wistar rats and rats with experimental Alzheimer's disease kept under standard conditions and in enriched (multistimulus) environment in vivo. Progenitor cells from healthy animals more rapidly formed neurospheres. Considerable changes at the early stages of in vitro development of brain progenitor cells were observed in both groups kept in enriched environment.

Glycolysis-mediated control of blood-brain barrier development and function

The blood-brain barrier (BBB) consists of differentiated cells integrating in one ensemble to control transport processes between the central nervous system (CNS) and peripheral blood. Molecular organization of BBB affects the extracellular content and cell metabolism in the CNS. Developmental aspects of BBB attract much attention in recent years, and barriergenesis is currently recognized as a very important and complex mechanism of CNS development and maturation. Metabolic control of angiogenesis/barriergenesis may be provided by glucose utilization within the neurovascular unit (NVU). The role of glycolysis in the brain has been reconsidered recently, and it is recognized now not only as a process active in hypoxic conditions, but also as a mechanism affecting signal transduction, synaptic activity, and brain development. There is growing evidence that glycolysis-derived metabolites, particularly, lactate, affect barriergenesis and functioning of BBB. In the brain, lactate produced in astrocytes or endothelial cells can be transported to the extracellular space via monocarboxylate transporters (MCTs), and may act on the adjoining cells via specific lactate receptors. Astrocytes are one of the major sources of lactate production in the brain and significantly contribute to the regulation of BBB development and functioning. Active glycolysis in astrocytes is required for effective support of neuronal activity and angiogenesis, while endothelial cells regulate bioavailability of lactate for brain cells adjusting its bidirectional transport through the BBB. In this article, we review the current knowledge with regard to energy production in endothelial and astroglial cells within the NVU. In addition, we describe lactate-driven mechanisms and action of alternative products of glucose metabolism affecting BBB structural and functional integrity in developing and mature brain.

Establishment of neurogenic microenvironment in the neurovascular unit: the connexin 43 story

Connexins (Cx) play an important role in the coordination of intercellular communication, and autocrine and paracrine regulation of cells within the neurovascular unit (NVU). Gap junctional mechanisms control proliferation and differentiation processes underlying neurogenesis and angiogenesis in the brain. Cx43 possesses some unique properties [the ability to form either intercellular channels permeable for regulatory molecules and ions or hemichannels open to the extracellular space to provide release of cell metabolites; functional coupling with nicotinamide adenine dinucleotide (NAD+)-consuming and NAD+-dependent enzymatic processes] which may be of great importance for the fate of the stem cells. Dynamic changes in Cx43 expression are associated with different stages of brain cells development either at embryonic or adult periods of ontogenesis. This review summarizes recent data on Cx43-controlled neurogenesis in the context of NVU development and functioning. Understanding the molecular mechanisms of gap junctional intercellular communication will support translational studies focused on the development of regeneration-based approaches for the therapy of central nervous system pathology.

[Changes in structural and functional plasticity of the brain induced by environmental enrichment]

The review contains current data on structural and functional brain plasticity mechanisms under the enriched environment. Enriched environment contains social and non-social stimuli acting on different aspects of the development and functioning of the brain. Special attention is devoted to the modeling of enriched environment in the experiment. Enriched environment implies the action of social stimuli, new objects, therefore the enriched environment in animals can be considered as an adequate model to study changes in brain structure and function in people during learning or acquiring complex skills. The review describes the theory of enriched environment's influence on neurogenesis, the neuron-glia relationships, and the impact of enriched environment on damaged brain as well as the possibilities of using the paradigm of enriched envimronmentfor neurorenhabilitation. Molecular mechanisms of synaptic transmission, which has a correlation with the performance of cognitive functions, are the possible target for the action of environmental factors at the brain under (patho)physiological conditions. The considerable progress has been done in understanding the mechanisms that mediate the effects of enriched environment on the brain, but still there are many non-resolved questions in the neurochemistry and neurobiology of this phenomenon. Overall, the experience-induced neuroplasticity is a unique mechanism for the development and recovery of brain functions. It opens new perspectives in neuropharmacology and neurorehabilitation.

[NAD+-converting enzymes in neuronal and glial cells: CD38 as a novel target for neuroprotection]

The review contains current data on molecular mechanisms which control NAD+ homeostasis in brain cells. It also deals with the role of NAD+-converting enzymes in regulation of functional activity, viability and intercellular communication of neuronal and glial cells. Special attention is paid to involvement of CD38 into regulation of NAD+ levels in brain cells in normal and pathological conditions.

[Modulation of membrane blebbing and microparticle sheddimg as a target of cardiovascular prophylaxis]

Physicocemical and antigenic properties of peripheral blood lymphocytes and shed membrane microparticles were studied in patients with CHD and angina of effort and in those with hypertensive disease. The frequency of lymphocyte blebbing in CHD and angina patients was significantly higher than in those with HD (70.56, 52, 25.7% respectively). Incubation with rotenone and zymosan resulted in an increase of lymphocyte blebbing to 77.34 and 86.5% vs the initial level of 70.56% (p < 0.05). Patients of both groups had an increased number of membrane microparticles in peripheral blood (59.6 and 78.2 U/4 cm2 respectively). It is concluded that modulation of Imphocyte blebbing and microparticle shedding may be a promising target of cardiovascular prophylaxis.

[The role of P2X7 receptors in modulation of the functional activity of peritoneal macrophages in mice with peritonitis]

The role of P2X7 receptors in modulation of the functional activity of macrophages in mice with model peritonitis has been studied. It is established that the functional activity of murine macrophages under such conditions is increased, which is accompanied by the growth of P2X7(+) macrophages and a bidirectional change of the their functional activity under the action of P2X7 modulators. The role of P2X7-associated mechanisms in regulation of the macrophage activity during inflammation is discussed.