Research Interests:
Research Interests:
ABSTRACT Previous studies showed the presence of glial fibrillary acidic protein (GFAP) in cells located at different blood—tissue interfaces (astrocytes, hepatic stellate cells, kidney glomeruli mesangial cells, alveolar fibroblasts),... more
ABSTRACT Previous studies showed the presence of glial fibrillary acidic protein (GFAP) in cells located at different blood—tissue interfaces (astrocytes, hepatic stellate cells, kidney glomeruli mesangial cells, alveolar fibroblasts), the blood-urine interface (podocytes), and air-body interface (skin keratinocytes and fibroblasts). Similar features of these cells hinted at the comparability of tasks at different metabolically active regions. In the present study performed with adult rat heart and spleen sections, anti-GFAP antibodies were immunoreacted with interstitial Cajal-like cells in close proximity to capillaries, between the striated muscles of the myocardium, and along the lumen of the ventricles. In spleen sections, anti-GFAP antibodies labeled cells associated with capillaries, follicular arteriole, central artery, and marginal sinuses separating two functionally different regions of the spleen: the white and red pulp. This study presents yet another example of the immunoreactivity of GFAP at the border of the blood-tissue interface that, again, supports our hypothesis concerning the importance of the GFAP cytoskeleton in intracellular functions associated with the exchange between metabolically different environments.
Research Interests: Biology and Neurochemical
The enzyme S-adenosyl-homocysteine hydrolase (AdoHcyase) which catalyzes the reversible hydrolysis of AdoHcy to adenosine and homocysteine is an adenosine binding protein. In the present study we examined the characteristics of [(3)H]cAMP... more
The enzyme S-adenosyl-homocysteine hydrolase (AdoHcyase) which catalyzes the reversible hydrolysis of AdoHcy to adenosine and homocysteine is an adenosine binding protein. In the present study we examined the characteristics of [(3)H]cAMP binding to purified AdoHcyase from bovine kidney in comparison with the high affinity adenosine binding site of AdoHcyase. AdoHcyase exhibits one [(3)H]cAMP binding site with an affinity of K(d)=23.1+/-1.1nM and a B(max) of 116.6+/-3.8pmol/mg protein. Binding of [(3)H]cAMP obeyed a monophasic reaction with a k(+1) value of 0.035min/M. The dissociation of AdoHcyase-[(3)H]cAMP complex exhibited a time- and temperature-dependent character. After a 240min incubation at 0 degrees only 5-10%, however, at 20 degrees 90% were displaceable. Adenosine and cAMP displace each other with similar affinities of EC(50) 57nM vs. EC(50) 65nM. 2'-Deoxyadenosine, N(6)-methyladenosine, and NECA displace 25nM [(3)H]cAMP and 10nM [(3)H]adenosine with EC(50) values of 94, 90 and 80nM, respectively. All other nucleosides studied, adenine, inosine, adenosine-2',3'-dialdehyde, 2-chloroadenosine, aristeromycin, and adenine nucleotides were only week competitors for [(3)H]cAMP and [(3)H]adenosine. These compounds displace [(3)H]cAMP and [(3)H]adenosine with equal potencies. Our data indicate that the binding site for nanomolar concentrations of cAMP and adenosine at the AdoHcyase appears to be identical. The physiological implications of a cAMP binding site at the AdoHcyase remain to be established.
Research Interests: Chemistry, Medicine, Adenosine, Kidney, cyclic AMP, and 15 moreAnimals, Stereochemistry, Homocysteine, Enzyme, Temperature Dependence, Cattle, Theophylline, Tritium, BIOCHEMICAL PHARMACOLOGY, Protein Binding, Binding Site, Nucleotides, Adenosine monophosphate, binding sites, and Pharmacology and pharmaceutical sciences
Amyloid-beta (Aβ) deposition in the brain is the main pathological hallmark of Alzheimer disease. Peripheral clearance of Aβ may possibly also lower brain levels. Recent evidence suggested that hepatic clearance of Aβ42 is impaired in... more
Amyloid-beta (Aβ) deposition in the brain is the main pathological hallmark of Alzheimer disease. Peripheral clearance of Aβ may possibly also lower brain levels. Recent evidence suggested that hepatic clearance of Aβ42 is impaired in liver cirrhosis. To further test this hypothesis, serum Aβ42 was measured by ELISA in portal venous serum (PVS), systemic venous serum (SVS), and hepatic venous serum (HVS) of 20 patients with liver cirrhosis. Mean Aβ42 level was 24.7 ± 20.4 pg/mL in PVS, 21.2 ± 16.7 pg/mL in HVS, and 19.2 ± 11.7 pg/mL in SVS. Similar levels in the three blood compartments suggested that the cirrhotic liver does not clear Aβ42. Aβ42 was neither associated with the model of end-stage liver disease score nor the Child–Pugh score. Patients with abnormal creatinine or bilirubin levels or prolonged prothrombin time did not display higher Aβ42 levels. Patients with massive ascites and patients with large varices had serum Aβ42 levels similar to patients without these complic...
Research Interests:
Research Interests:
The general approach of the so far developed technologies is the attempt to increase the homing rate of transplanted stem cells by modifying the molecules/receptors that interact directly with the chemokines/ligands in the damaged tissue.... more
The general approach of the so far developed technologies is the attempt to increase the homing rate of transplanted stem cells by modifying the molecules/receptors that interact directly with the chemokines/ligands in the damaged tissue. Our unique technology does not interact with the natural repertoire of specific molecules/receptors mediating homing of stem cells to the damaged tissue (SPECIFIC HOMING) but impairs the function of molecules/receptors that are responsible for the adhesion of stem cells throughout the non-damaged vasculature (NON-SPECIFIC CELL ADHESION). Moreover and most importantly, our highly effective technology is non-toxic, does not affect stem cell function and does not require genetic modifications thus making it a most promising candidate for clinical us
Research Interests: Chemistry, Regeneration, Stem Cells, Cell Adhesion, Cell Biology, and 3 moreStem Cell, Homing, and Vessel
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Medicine, Western blotting, Striatum, Humans, Animals, and 15 moreMale, Substantia nigra, Mesenchymal Stem Cell, Tyrosine Hydroxylase, Clinical Sciences, Rats, HeLa cells, Rejuvenation, Interleukins, Olfactory Bulb, Cell Proliferation, Intranasal Administration, Mesenchymal Stromal Cells, Parkinson Disease, and TUNEL-assay
Research Interests: Aging, Biology, Immunohistochemistry, Dexamethasone, Humans, and 15 moreChild, Keratinocytes, Animals, Astrocyte, Detoxification, Enzyme, Glutamine, Glial Fibrillary Acidic Protein, Glutamine Synthetase, Enzymatic Activity, Enzyme Induction, Adherens Junction, Cell count, Glycogen Synthase Kinase, and Human skin
Most skin pathologies are characterized by unbalanced synthesis of major histocompatability complex II (MHC-II) proteins. Healthy skin keratinocytes simultaneously produce large amounts of MHC-II and regeneration-supporting proteins, e.g.... more
Most skin pathologies are characterized by unbalanced synthesis of major histocompatability complex II (MHC-II) proteins. Healthy skin keratinocytes simultaneously produce large amounts of MHC-II and regeneration-supporting proteins, e.g. erythropoietin (EPO), EPO receptor (EPOR), glutamine synthetase (GS) and metallothionein (MT). To investigate the level of regeneration-supporting proteins in the skin during misbalanced production of MHC-II, skin sections from nonobese diabetic/severe combined immunodeficient (NOD/SCID)/gamma (c) (null) and or Foxn1 nu/nu mice which are a priory known to under- and over-express MHC II, respectively, were used. Double immunofluorescence analysis of NOD/SCID/gamma (c) (null) skin sections showed striking decrease in expression of MHC-II, EPO, GS and MT. In Foxn1 nu/nu mouse skin, GS was strongly expressed in epidermis and in hair follicles (HF), which lacked EPO. In nude mouse skin EPO and MHC-II were over-expressed in dermal fibroblasts and they were completely absent from cortex, channel, medulla and keratinocytes surrounding the HF, suggest a role for EPO in health and pathology of hair follicle. The level of expression of EPO and GS in both mutant mice was confirmed by results of Western blot analyses. Strong immunoresponsiveness of EPOR in the hair channels of NOD/SCID/gamma (c) (null) mouse skin suggests increased requirements of skin cells for EPO and possible benefits of exogenous EPO application during disorders of immune system accompanied by loss MHC-II in skin cells.
Research Interests: Biology, Medicine, Biological Sciences, Erythropoietin, Mice, and 15 moreAnimals, Metallothionein, Skin, MHC class II, Fluorescent Antibody Technique, Immune system, Major histocompatibility complex, Western blot, Species Specificity, Glutamine Synthetase, Hair Follicle, Severe combined immunodeficiency, Neurochemical, nod, and Medical and Health Sciences
Research Interests:
Research Interests:
The enzyme S-adenosyl-homocysteine hydrolase (AdoHcyase) which catalyzes the reversible hydrolysis of AdoHcy to adenosine and homocysteine is an adenosine binding protein. In the present study we examined the characteristics of [(3)H]cAMP... more
The enzyme S-adenosyl-homocysteine hydrolase (AdoHcyase) which catalyzes the reversible hydrolysis of AdoHcy to adenosine and homocysteine is an adenosine binding protein. In the present study we examined the characteristics of [(3)H]cAMP binding to purified AdoHcyase from bovine kidney in comparison with the high affinity adenosine binding site of AdoHcyase. AdoHcyase exhibits one [(3)H]cAMP binding site with an affinity of K(d)=23.1+/-1.1nM and a B(max) of 116.6+/-3.8pmol/mg protein. Binding of [(3)H]cAMP obeyed a monophasic reaction with a k(+1) value of 0.035min/M. The dissociation of AdoHcyase-[(3)H]cAMP complex exhibited a time- and temperature-dependent character. After a 240min incubation at 0 degrees only 5-10%, however, at 20 degrees 90% were displaceable. Adenosine and cAMP displace each other with similar affinities of EC(50) 57nM vs. EC(50) 65nM. 2'-Deoxyadenosine, N(6)-methyladenosine, and NECA displace 25nM [(3)H]cAMP and 10nM [(3)H]adenosine with EC(50) values of 94, 90 and 80nM, respectively. All other nucleosides studied, adenine, inosine, adenosine-2',3'-dialdehyde, 2-chloroadenosine, aristeromycin, and adenine nucleotides were only week competitors for [(3)H]cAMP and [(3)H]adenosine. These compounds displace [(3)H]cAMP and [(3)H]adenosine with equal potencies. Our data indicate that the binding site for nanomolar concentrations of cAMP and adenosine at the AdoHcyase appears to be identical. The physiological implications of a cAMP binding site at the AdoHcyase remain to be established.
Research Interests: Chemistry, Medicine, Adenosine, Kidney, cyclic AMP, and 15 moreAnimals, Stereochemistry, Homocysteine, Enzyme, Temperature Dependence, Cattle, Theophylline, Tritium, BIOCHEMICAL PHARMACOLOGY, Protein Binding, Binding Site, Nucleotides, Adenosine monophosphate, binding sites, and Pharmacology and pharmaceutical sciences
Research Interests:
Huntington’s disease (HD) is a monogenetic neurodegenerative disorder characterized by the accumulation of polyglutamine-expanded huntingtin (mHTT). There is currently no cure, and therefore disease-slowing remedies are sought to... more
Huntington’s disease (HD) is a monogenetic neurodegenerative disorder characterized by the accumulation of polyglutamine-expanded huntingtin (mHTT). There is currently no cure, and therefore disease-slowing remedies are sought to alleviate symptoms of the multifaceted disorder. Encouraging findings in Alzheimer’s and Parkinson’s disease on alpha-2 adrenoceptor (α2-AR) inhibition have shown neuroprotective and aggregation-reducing effects in cell and animal models. Here, we analyzed the effect of beditin, a novel α2- adrenoceptor (AR) antagonist, on cell viability and mHTT protein levels in cell models of HD using Western blot, time-resolved Foerster resonance energy transfer (TR-FRET), lactate dehydrogenase (LDH) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) cytotoxicity assays. Beditin decreases cytotoxicity, as measured by TUNEL staining and LDH release, in a neuronal progenitor cell model (STHdh cells) of HD and decreases the aggregation propensity of H...
Research Interests:
The function and regulation of amyloid-beta (Aβ) in healthy and diseased liver remains unexplored. Because Aβ reduces the integrity of the blood-brain barrier we have examined its potential role in regulating the sinusoidal permeability... more
The function and regulation of amyloid-beta (Aβ) in healthy and diseased liver remains unexplored. Because Aβ reduces the integrity of the blood-brain barrier we have examined its potential role in regulating the sinusoidal permeability of normal and cirrhotic liver. Aβ and key proteins that generate (beta-secretase 1 and presenilin-1) and degrade it (neprilysin and myelin basic protein) were decreased in human cirrhotic liver. In culture, activated hepatic stellate cells (HSC) internalized Aβ more efficiently than astrocytes and HSC degraded Aβ leading to suppressed expression of α-smooth muscle actin (α-SMA), collagen 1 and transforming growth factor β (TGFβ). Aβ also upregulated sinusoidal permeability marker endothelial NO synthase (eNOS) and decreased TGFβ in cultured human liver sinusoidal endothelial cells (hLSEC). Liver Aβ levels also correlate with the expression of eNOS in transgenic Alzheimer’s disease mice and in human and rodent cirrhosis/fibrosis. These findings sugges...
Research Interests:
The noradrenergic system is proposed to play a prominent role in the pathogenesis of liver fibrosis. While α1- and β-adrenergic receptors (ARs) are suggested to be involved in a multitude of profibrogenic actions, little is known about... more
The noradrenergic system is proposed to play a prominent role in the pathogenesis of liver fibrosis. While α1- and β-adrenergic receptors (ARs) are suggested to be involved in a multitude of profibrogenic actions, little is known about α2-AR-mediated effects and their expression pattern during liver fibrosis and cirrhosis. We explored the expression of α2-AR in two models of experimental liver fibrosis. We further evaluated the capacity of the α2-AR blocker mesedin to deactivate hepatic stellate cells (HSCs) and to increase the permeability of human liver sinusoidal endothelial cells (hLSECs). The mRNA of α2a-, α2b-, and α2c-AR subtypes was uniformly upregulated in carbon tetrachloride-treated mice vs the controls, while in bile duct-ligated mice, only α2b-AR increased in response to liver injury. In murine HSCs, mesedin led to a decrease in α-smooth muscle actin, transforming growth factor-β and α2a-AR expression, which was indicated by RT-qPCR, immunocytochemistry, and Western blo...
Research Interests:
Research Interests:
Intrastriatal administration of mesenchymal stem cells (MSCs) has shown beneficial effects in rodent models of Huntington disease (HD). However, the invasive nature of surgical procedure and its potential to trigger the host immune... more
Intrastriatal administration of mesenchymal stem cells (MSCs) has shown beneficial effects in rodent models of Huntington disease (HD). However, the invasive nature of surgical procedure and its potential to trigger the host immune response may limit its clinical use. Hence, we sought to evaluate the non-invasive intranasal administration (INA) of MSC delivery as an effective alternative route in HD. GFP-expressing MSCs derived from bone marrow were intranasally administered to 4-week-old R6/2 HD transgenic mice. MSCs were detected in the olfactory bulb, midbrain and striatum five days post-delivery. Compared to phosphate-buffered saline (PBS)-treated littermates, MSC-treated R6/2 mice showed an increased survival rate and attenuated circadian activity disruption assessed by locomotor activity. MSCs increased the protein expression of DARPP-32 and tyrosine hydroxylase (TH) and downregulated gene expression of inflammatory modulators in the brain 7.5 weeks after INA. While vehicle tr...
Research Interests:
Research Interests:
Research Interests:
In view of the rapid preclinical development of cell-based therapies for neurodegenerative disorders, traumatic brain injury, and tumors, the safe and efficient delivery and targeting of therapeutic cells to the central nervous system is... more
In view of the rapid preclinical development of cell-based therapies for neurodegenerative disorders, traumatic brain injury, and tumors, the safe and efficient delivery and targeting of therapeutic cells to the central nervous system is critical for maintaining therapeutic efficacy and safety in the respective disease models. Our previous data demonstrated therapeutically efficacious and targeted delivery of mesenchymal stem cells (MSCs) to the brain in the rat 6-hydroxydopamine model of Parkinson's disease (PD). The present study examined delivery of bone marrow-derived MSCs, macrophages, and microglia to the brain in a transgenic model of PD [(Thy1)-h[A30P] αS] and an APP/PS1 model of Alzheimer's disease (AD) via intranasal application (INA). INA of microglia in naive BL/6 mice led to targeted and effective delivery of cells to the brain. Quantitative PCR analysis of eGFP DNA showed that the brain contained the highest amount of eGFP-microglia (up to 2.1 × 10(4)) after IN...
Research Interests: Technology, Flow Cytometry, Macrophages, Biological Sciences, Cell Differentiation, and 14 moreBrain, Mice, Female, Animals, Microglia, Male, Cell Transplantation, Biological markers, Intranasal Administration, Alzheimer Disease, Mesenchymal Stromal Cells, Parkinson Disease, Bone Marrow Cells, and Medical and Health Sciences
Research Interests:
Research Interests:
Research Interests:
Research Interests: International organizations, Humans, Keratinocytes, Mice, Animals, and 15 moreAntigen Presentation, Metallothionein, Lung, Epidermis, Clinical Sciences, Rats, Major histocompatibility complex, Western blot, Glial Fibrillary Acidic Protein, International Organizations, Hair Follicle, Vascular Permeability, Nude mice, Severe combined immunodeficiency, and fibroblasts
Our recent study [Danielyan et al., 2005. Eur. J. Cell Biol. 84, 567-579] showed an additive protective effect of endothelin (ET) receptor A (ETA-R) blockade and erythropoietin (EPO) on the survival and rejuvenation of rat astroglial... more
Our recent study [Danielyan et al., 2005. Eur. J. Cell Biol. 84, 567-579] showed an additive protective effect of endothelin (ET) receptor A (ETA-R) blockade and erythropoietin (EPO) on the survival and rejuvenation of rat astroglial cells exposed to hypoxia. Whether the effects observed with rodent astroglial cells can be reproduced in human astrocytes and whether these effects of ETA-R blockade and EPO on astrocytes are associated with neuronal survival remained open. Therefore, in the present study, the effects of the ETA-R antagonist BQ-123 and EPO on the maintenance of the neuronal population and survival of the human fetal astroglial cell line (SV-FHAS) under normoxic and hypoxic conditions (NC and HC, respectively) were investigated. Rat brain primary cultures exposed to BQ-123 and/or EPO revealed an increase in the number of beta-III tubulin-positive neurons under NC. The hypoxia-caused loss of neurons was abolished by administration of BQ-123 or EPO. Simultaneous application of EPO and BQ-123 led to an additive protective effect on the generation of neurons under NC only. By contrast, BQ-788, the selective ETB-R antagonist, diminished the neuronal population both in NC and HC. Both under NC and HC the number of non-differentiated nestin+/GFAP- neural cells increased upon application of EPO or BQ-123. SV-FHAS responded to BQ-123 or EPO by a decrease in LDH activity in the culture medium under NC (35%) and HC (26% LDH decrease). Concomitant effects of EPO and BQ-123 were illustrated in an additional increase in the survival of human astrocytes (33% under NC and 17% under HC). These data hint at a neuroprotective therapeutic potency of ETA-R blockade, which either alone or in combination with EPO may improve the survival of astroglial and neuronal cells upon hypoxic injury.
Research Interests: Cell Adhesion, Hypoxia, Immunohistochemistry, Erythropoietin, Cell line, and 15 moreBrain, Humans, Animals, Astrocyte, Cyclic peptides, Rat Brain, Differentiation, Astrocytes, Rats, Wistar Rats, Primary Culture, Cell Survival, Biochemistry and cell biology, Neuroprotective Agents, and culture medium
Research Interests:
The safety and efficacy of cell-based therapies for neurodegenerative diseases depends on the mode of cell administration. We hypothesized that intranasally administered cells could bypass the blood-brain barrier by migrating from the... more
The safety and efficacy of cell-based therapies for neurodegenerative diseases depends on the mode of cell administration. We hypothesized that intranasally administered cells could bypass the blood-brain barrier by migrating from the nasal mucosa through the cribriform plate along the olfactory neural pathway into the brain and cerebrospinal fluid (CSF). This would minimize or eliminate the distribution of cellular grafts to peripheral organs and will help to dispense with neurosurgical cell implantation. Here we demonstrate transnasal delivery of cells to the brain following intranasal application of fluorescently labeled rat mesenchymal stem cells (MSC) or human glioma cells to naive mice and rats. After cells crossed the cribriform plate, two migration routes were identified: (1) migration into the olfactory bulb and to other parts of the brain; (2) entry into the CSF with movement along the surface of the cortex followed by entrance into the brain parenchyma. The delivery of cells was enhanced by hyaluronidase treatment applied intranasally 30 min prior to the application of cells. Intranasal delivery provides a new non-invasive method for cell delivery to the CNS.
Research Interests: Immunohistochemistry, Stem Cell Transplantation, Cell line, Cerebrospinal Fluid, Mesenchymal stem cells, and 15 moreBrain, Humans, Mice, Blood brain barrier, Female, Animals, Mesenchymal Stem Cell, CD, Rats, Neurodegenerative Disease, Olfactory Bulb, Olfactory Pathways, Mesenchymal Stromal Cells, Biochemistry and cell biology, and In Vitro Techniques
The safety and efficacy of cell-based therapies for neurodegenerative diseases depends on the mode of cell administration. We hypothesized that intranasally administered cells could bypass the blood-brain barrier by migrating from the... more
The safety and efficacy of cell-based therapies for neurodegenerative diseases depends on the mode of cell administration. We hypothesized that intranasally administered cells could bypass the blood-brain barrier by migrating from the nasal mucosa through the cribriform plate along the olfactory neural pathway into the brain and cerebrospinal fluid (CSF). This would minimize or eliminate the distribution of cellular grafts to peripheral organs and will help to dispense with neurosurgical cell implantation. Here we demonstrate transnasal delivery of cells to the brain following intranasal application of fluorescently labeled rat mesenchymal stem cells (MSC) or human glioma cells to naive mice and rats. After cells crossed the cribriform plate, two migration routes were identified: (1) migration into the olfactory bulb and to other parts of the brain; (2) entry into the CSF with movement along the surface of the cortex followed by entrance into the brain parenchyma. The delivery of cells was enhanced by hyaluronidase treatment applied intranasally 30 min prior to the application of cells. Intranasal delivery provides a new non-invasive method for cell delivery to the CNS.