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. 

STRUCTURAL AND FUNCTIONAL HETEROGENEITY OF ASTROCYTES IN THE BRAIN: ROLE IN NEURODEGENERATION AND NEUROINFLAMMATION

The review covers the current concepts on structural and functional heterogeneity of brain astrocytes that serve for numerous (patho)physiological processes in the central nervous system. Astrocytes from various subpopulations demonstrate different sensitivity to the action of pathogenic factors, varied behaviors in reactive processes and within the local immune response. Key functions of astrocytes like neurogenesis, neuron-astroglia metabolic coupling, glial control of local blood flow greatly depend on the origin and characteristics of astroglial cells. Changes at the initial stages of neurodegeneration or in neurodevelopmental disorders are associated with significant alterations in astroglial structural and functional properties, thus suggesting new approaches to therapeutic strategies implementing astroglia-expressing molecules and targets for effective

CURRENT CONCEPTS OF PERINATAL ISCHEMIC INJURY IN THE BRAIN NEUROVASCULAR UNIT: MOLECULAR TARGETS FOR NEUROPROTECTION

Perinatal hypoxic-ischemic brain injury is a relevant medical and social problem. Among many pathological processes in the neonatal period perinatal hypoxic-ischemic injury is a major cause of further hemorrhage, necrotic and atrophic changes in the brain.  This review presents recent data on the basic mechanisms of the hypoxic-ischemic brain injury along the concept of neurovascular unit (neurons, astrocytes, endothelial cells, pericytes) with the focus on alterations in cell-to-cell communication. Pathological changes caused by ischemia-hypoxia are considered within two phases of injury (ischemic phase and reperfusion phase). The review highlights changes in each individual component of the neurovascular unit and their interactions. Molecular targets for pharmacological improvement of intercellular communication within neurovascular unit as a therapeutic strategy in perinatal brain injury are discussed. 

Neurogenic Potential of Implanted Neurospheres Is Regulated by Optogenetic Stimulation of Hippocampal Astrocytes Ex Vivo

The protocol of optogenetic ChR2-mediated activation of astrocytes was used in a model of artificial neurogenic niche, neurospheres implanted into ex vivo organotypic cultures of mouse hippocampus. The electrophysiological characteristics of the hippocampus and expression of molecules involved in the mechanisms of activation of astrocytes and microglia (GFAP, CD38, C3/C3b, Cx43, CD11b, and CD18) were evaluated. Photoactivation of astrocytes led to activation of neurogenesis and changes in the expression of molecules (Cx43 and CD38) that determine bioavailability of NAD⁺ to ensure proliferative activity of cells in the neurogenic niche. Implantation of neurospheres into organotypic slices of the hippocampus caused an increase in C3/C3b expression and suppression of the synaptic plasticity of hippocampal neurons.

Inhibition of Apoptosis is a Potential Way to Improving Ischemic Brain Tolerance in Combined Exposure to Hypercapnia and Hypoxia

We compared the intensity of apoptosis in the peri-infarction area of the brain after isolated and combined exposure to hypoxia and hypercapnia prior to focal ischemic stroke modeling. Hypoxia and hypercapnia reduced the number of TUNEL-positive cells in the peri-infarction area, and their combination was most effective in comparison with effects of isolated exposures. The maximum neuroprotective effect of combined exposure to hypoxia and hypercapnia in comparison with isolated exposures was determined by inhibition of apoptosis in the peri-infarction zone.

[Features of the in vitro expression profile of hippocampal neurogenic niche cells during optogenetic stimulation]

In the central nervous system of mammals, there are specialized areas in which neurogenesis - neurogenic niches - is observed in the postnatal period. It is believed that astrocytes in the composition of neurogenic niches play a significant role in the regulation of neurogenesis, and therefore they are considered as a promising "target" for the possible control of neurogenesis, including the use of optogenetics. In the framework of this work, we formed an in vitro model of a neurogenic niche, consisting of cerebral endothelial cells, astrocytes and neurospheres. Astrocytes in the neurogenic niche model expressed canalorodopsin ChR2 and underwent photoactivation. The effect of photoactivated astrocytes on the expression profile of neurogenic niche cells was evaluated using immunocytochemical analysis methods. It was found that intact astrocytes in the composition of the neurogenic niche contribute to neuronal differentiation of stem cells, as well as the activation of astroglia expressing photosensitive proteins, changes the expression of molecules characterized by intercellular interactions of pools of resting and proliferating cells in the composition of the neurogenic niche with the participation of NAD+ (Cx43, CD38, CD157), lactate (MCT1). In particular, the registered changes reflect a violation of the paracrine intercellular interactions of two subpopulations of cells, one of which acts as a source of NAD+, and the second as a consumer of NAD+ to ensure the processes of intracellular signal transduction; a change in the mechanisms of lactate transport due to aberrant expression of the lactate transporter MCT1 in cells forming a pool of cells developing along the neuronal path of differentiation. In general, with photostimulation of niche astrocytes, the total proliferative activity increases mainly due to neural progenitor cells, but not neural stem cells. Thus, optogenetic activation of astrocytes can become a promising tool for controlling the activity of neurogenesis processes and the formation of a local proneurogenic microenvironment in an in vitro model of a neurogenic niche.

[Effect of sliding discharge on proliferation and death of brain microvessel endothelial cells in vitro]

The dose-dependent effects of plasma exposure to a unipolar nanosecond sliding discharge over the surface of the culture medium in a closed plate on the cells of cerebral endothelium in vitro were studied. Using a 24-well plate, the surface plasma energy density of one pulse was 360 μJ/cm2 at a pulse frequency of 100 Hz. It has been shown that in the creeping discharge plasma there is an active excitation of air molecules, the formation of positive nitrogen and oxygen ions, and the formation of carbon monoxide. In the dose density range of 0-32 J/cm2, the dose-dependent effects were assessed in the 4-12 h post-radiation period. Cell death was analyzed with an assessment of the total number of cells, necrotic cells, cells in apoptosis (phosphatidylserine externalization, internucleosomal DNA fragmentation) and their proliferative activity (Ki67-immunopositive cells). A preliminary assessment of subtle dose-dependent effects indicates the peculiarities of the effect of small doses.

TIGHT JUNCTIONS PROTEINS IN CEREBRAL ENDOTHELIAL CELLS DURING EARLY POSTNATAL DEVELOPMENT

Formation and functional plasticity of the blood-brain barrier is associated with the molecular events that occur in the brain neurovascular unit in the embryonic and early postnatal development. To study the characteristics of barriergenesis under physiological conditions, as well as recovering from perinatal hypoxia and early life stress, we examined the expression of proteins of cerebral endothelial tight junctions (JAM, ZO1, CLDN5) in rats aged 7, 28 and 70 days of postnatal development (P7—P70). Under physiological conditions, we have found that the number of endothelial cells expressing JAM, ZO1, CLDN5 slightly increases in the cortex, hippocampus and amygdala of the brain in the period from P7 to P70. Perinatal hypoxia significantly increased the number of cells expressing proteins of tight junction proteins (JAM, CLDN5) up to the age P28—P70, whereas the number of cells expressing ZO1 was reduced in the same period of time. Early life stress led to an imbalance between the number of cells expressing ZO1 proteins and that expressing tight junctions proteins, but these changes were in opposite direction to that observed in perinatal hypoxia

[Plasma acid reproduces oxidative and nitrosative stress in bladder tissue in vitro: experimental study]

AIM

To analyze some effects of plasma acid in vitro on the bladder tissue obtained from laboratory animals and to evaluate the possibility of its application for in vitro modeling of IC/BPS.

MATERIALS AND METHODS

The tissue samples of the bladder wall were obtained from female Wistar rats aged 3 months (n=16, weighing 180-200 g). The tissues were processed for 1 hour in the plasma acid prepared by spark discharge of water for injection in air. The immunohistochemical study of obtained samples was performed.

RESULTS

The changes in the expression profile of bladder epithelial cells under the action of plasma acid in vitro were found indicating the development of oxidative, nitrosative and dicarbonyl stress, impaired expression of NADPH oxidase DUOX2 and VEGF, and a decrease in cell proliferative activity, which, in general, corresponds to the main mechanisms of urothelial alterations specific for the IC/BPS.

CONCLUSION

The revealed effects of plasma acid on bladder epithelial cells confirm the possibility of using it as an inducer of urothelial cell damage typical for IC/BPS in the in vitro models.

[MODULATION OF LACTATE PRODUCTION, TRANSPORT AND RECEPTION BY CELLS IN THE MODEL OF BRAIN NEUROVASCUL. UNIT I.]

Metabolic activity of cells within a neurovascular unit is among the factors determining structural and functional integritY of the blood-brain barrier and the an- giogenesis process. in order to verify the hypothesis about the role Of g1YcolYtic activity in the perivascula astroglialcells associated with lactate release in the development of functioning of cerebral microvessel endothelial cells, we have used a three-component model of the brain neurovascular unit in vitro. The cells o f n o n -en d o th elia l o rig in w ere in c u b a te d in th e p rese n ce o f m o d u la to rs o f la c ta te pro d u c n ago ni glu c ose ta a G ly c o s o) , bas t h e oe t a n t a at- blocker of monocarboxylate transporters MCTlprCT and recepltiors of3Ctate0produasan (2-donisyoflactate G e8 breceptor) Iasa estbishe vthat that te suppression of lactate production and transport, prdc o1,adrcpin(C-O-Aa n (2gdoxysgflucoase as a glycolysis inhibitor), transport (phloretin as a sukr of lacaroduto transport , aswellasastimultionof3lactate receptors in astroglial cells, lead to aberrant development of endothelial layer, ther by u g g e tin t h efor atio o f anti ngi gencmi roen ircm ent for cerebral endothelium due to inappropriate lactate-m ediated effects. KeYw.ords:-n-eur-ovascular unit; metabolism; glYcolysis; lactate.

[CLINICAL AND PATHOGENETIC PECULIARITIES OF DEVELOPMENT OF ENDOTHELIAL DYSFUNCTION]

The purpose of the study was to examine the relationship between functional parameters, arterial rigidity, lipid profile, markers of systemic inflammation and endothelial dysfunction in patients with COPD and COPD + coronary heart disease. We examined 110 subjects divided into 3 groups. G group 1 included 40 patients with severe and very severe COPD, group 2 consisted of 40 patients with severe and very severe COPD + coronary artery disease, the control group was comprised of 30 healthy volunteers. We studied parameters of respiratory function, the level of blood oxygenation, the main characteristics of arterial rigidity plasma lipid, TNF-α, CRP, fibrinogen, sPECAM-1 levels and the expression of CD38/ADP-ribosylcyclase in peripheral blood lymphocytes. The study revealed increased rigidity of the central arteries in the patients of groups 1and 2 regardless of the duration of observation and the presence of coronary artery disease, as evidenced by the increase of the pulse wave velocity in the aorta. Patients of both groups had elevated levels of TNF-α, CRP and fibrinogen indicating systemic inflammatory response. Taken together, the enhanced expression of CD38 in peripheral blood lymphocytes, elevated concentration of soluble CD31 (sPECAM-1) in both groups related to bronchial obstruction and neutrophil elastase activity as well as increased rigidity of the vascular bed gives evidence that the CD38 and sCD31 relationship plays a role in the formation of endothelial dysfunction, and dysregulation of vascular tone in COPD patients. Disorders of lipid metabolism combined with increased rigidity of the vascular wall, elevated levels of markers of systemic inflammation and endothelia dysfunction, suggest that patients with COPD are at risk of cardiovascular events.

Melatonin production in patients with duodenal ulcer

OBJECTIVES. This work was designed to study melatonin (M) production levels in duodenal ulcer (DU) patients in the exacerbation and remission stages and in DU patients with a different course of DU in the exacerbation and remission stages.

METHODS

DU patients (15 men aged 20 to 45, mean age 34,2 +/- 1,1 years) were studied. The control group included 11 healthy volunteers (men aged 20-45, mean age 32,5 +/- 1,4 years). M was measured by RIA-method using H(3)-labeled M in daily urine collected at 3-hour intervals (8 portions per day). Mathematical processing was carried out using ANOVA, Student's t-test, and cosinor analysis. Differences at p< or = 0,05 were considered to be significant.

RESULTS

A strong disturbance of M secretion in DU patients both in the exacerbation and remission stages and a direct correlation between the degree of M production disturbance and severity of clinical course of DU were revealed.

CONCLUSION

The obtained results suggest that circadian rhythms of M production are altered in DU patients. M was supposed to be involved in the pathogenesis of DU.

Effects of plasma acid on rat uterine tissue <i>in vitro</i>

The aim of the study was to evaluate the effect of plasma acid on the uterine tissue of laboratory animals in vitro.

Materials and methods. Treatment of dimethyl sulfoxide – water solution and water for injections with a spark discharge in air resulted in a decrease in pH, which contributed to generation of plasma acid in the solutions. We incubated uterine tissues in vitro in plasma acid at room temperature for 30 minutes. The treated tissues were examined histologically and immunohistochemically.

Results. We showed that plasma acid had pronounced biological activity. Immunohistochemistry was used to show that, depending on the type of a solution, plasma acid altered generation of nitrosative damage products (3-NT) and oxidative DNA damage (8-OHdG) and modulated the number of cells with high proliferative potential (including CD133+ cells) and production of vascular endothelial growth factor (VEGF). These effects contributed to the general cytotoxicity of plasma acid solutions.

Conclusion. During 30-minute exposure in vitro, plasma acid prepared from the dimethyl sulfoxide (DMSO) – water mixture exhibits various biological effects in uterine tissue samples obtained from experimental animals. Plasma-treated water exerts cytotoxic effects associated with oxidative DNA damage and promotes induction of pro-angiogenic activity in the uterine tissue. Plasma-treated DMSO does not have a cytotoxic effect. It inhibits cell proliferation, reducing the population of CD133+ cells and VEGF production in the tissue.