Protection of cultured brain endothelial cells from cytokine-induced damage by α-melanocyte stimulating hormone

Nicotinamide derivatives protect the blood-brain barrier against oxidative stress

Nicotinamides play a crucial role in energy metabolism and maintenance of the redox homeostasis counteracting oxidative stress and elevated reactive oxidative species (ROS) in human cells. The levels of nicotinamides decline with age and are associated with various pathologies, including ones linked with the blood-brain barrier disorder. Therefore, the investigation of the bioactivity of synthetic nicotinamide derivates (NAs) and evaluation of their potential to protect the blood-brain barrier (BBB) from oxidative stress is emerging as an important new strategy. In the current study, we tested different NAs as potential exogenous substitutes for such biological processes. All tested derivatives were non-toxic and attenuated elevation of ROS production in brain endothelial cells induced by tert-butyl hydroperoxide (tBHP), but one specifically was protective on the cell-cultured model of the BBB. The most promising NA was a derivative containing methoxy moiety (NA-4OCH3), which not only increased cell impedance, but had a protective effect on brain endothelial cells barrier against tBHP-induced oxidative stress on several levels: reducing the ROS level and restoring the activity of glutathione, mitochondrial membrane potential, superoxide dismutase enzymes activity to the basal level. In addition, NA-4OCH3 increased the integrity of both human and rat cell-based BBB model after tBHP-treatment seen by the elevated transendothelial electrical resistance, tight junction protein claudin-5 level as well as the decreased permeability of markers across the barrier. This study highlights novel approach to protect the BBB from oxidative stress-induced dysfunction, positioning NA-4OCH3 as potential neuroprotective agent for ROS-mediated disease interventions, with implications for neurodegeneration and BBB.

Alanine and glutathione targeting of dopamine- or ibuprofen-coupled polypeptide nanocarriers increases both crossing and protective effects on a blood-brain barrier model

BACKGROUND

Targeting the blood-brain barrier (BBB) is a key step for effective brain delivery of nanocarriers. We have previously discovered that combinations of BBB nutrient transporter ligands alanine and glutathione (A-GSH), increase the permeability of vesicular and polypeptide nanocarriers containing model cargo across the BBB. Our aim was to investigate dopamine- and ibuprofen-coupled 3-armed poly(L-glutamic acid) nanocarriers targeted by A-GSH for transfer across a novel human co-culture model with induced BBB properties. In addition, the protective effect of ibuprofen containing nanoparticles on cytokine-induced barrier damage was also measured.

METHOD

Drug-coupled nanocarriers were synthetized and characterized by dynamic light scattering and transmission electron microscopy. Cellular effects, uptake, and permeability of the nanoparticles were investigated on a human stem cell-based co-culture BBB model with improved barrier properties induced by a small molecular cocktail. The model was characterized by immunocytochemistry and permeability for marker molecules. Nanocarrier uptake in human brain endothelial cells and midbrain organoids was quantified by spectrofluorometry and visualized by confocal microscopy. The mechanisms of cellular uptake were explored by addition of free targeting ligands, endocytic and metabolic inhibitors, co-localization of nanocarriers with intracellular organs, and surface charge modification of cells. The protective effect of ibuprofen-coupled nanocarriers was investigated against cytokine-induced barrier damage by impedance and permeability measurements.

RESULTS

Targeted nanoformulations of both drugs showed elevated cellular uptake in a time-dependent, active manner via endocytic mechanisms. Addition of free ligands inhibited the cellular internalization of targeted nanocarriers suggesting the crucial role of ligands in the uptake process. A higher permeability across the BBB model was measured for targeted nanocarriers. After crossing the BBB, targeted dopamine nanocarriers subsequently entered midbrain-like organoids derived from healthy and Parkinson's disease patient-specific stem cells. The ibuprofen-coupled targeted nanocarriers showed protective effects against cytokine-induced barrier damage.

CONCLUSION

BBB-targeted polypeptide nanoparticles coupled to therapeutic molecules were effectively taken up by brain organoids or showing a BBB protective effect indicating potential applications in nervous system pathologies.

Peptoid-Cross-Linked Hydrogel Stiffness Modulates Human Mesenchymal Stromal Cell Immunoregulatory Potential in the Presence of Interferon-Gamma

Human mesenchymal stromal cell (hMSC) manufacturing requires the production of large numbers of therapeutically potent cells. Licensing with soluble cytokines improves hMSC therapeutic potency by enhancing secretion of immunoactive factors but typically decreases proliferative ability. Soft hydrogels, however, have shown promise for boosting immunomodulatory potential, which may compensate for decreased proliferation. Here, hydrogels are cross-linked with peptoids of different secondary structures to generate substrates of various bulk stiffnesses but fixed network connectivity. Secretions of interleukin 6, monocyte chemoattractive protein-1, macrophage colony-stimulating factor, and vascular endothelial growth factor are shown to depend on hydrogel stiffness in the presence of interferon gamma (IFN-γ) supplementation, with soft substrates further improving secretion. The immunological function of these secreted cytokines is then investigated via coculture of hMSCs seeded on hydrogels with primary peripheral blood mononuclear cells (PBMCs) in the presence and absence of IFN-γ. Cocultures with hMSCs seeded on softer hydrogels show decreased PBMC proliferation with IFN-γ. To probe possible signaling pathways, immunofluorescent studies probe the nuclear factor kappa B pathway and demonstrate that IFN-γ supplementation and softer hydrogel mechanics lead to higher activation of this pathway. Overall, these studies may allow for production of more efficacious therapeutic hMSCs in the presence of IFN-γ.

17-Oxime ethers of oxidized ecdysteroid derivatives modulate oxidative stress in human brain endothelial cells and dose-dependently might protect or damage the blood-brain barrier

20-Hydroxyecdysone and several of its oxidized derivatives exert cytoprotective effect in mammals including humans. Inspired by this bioactivity of ecdysteroids, in the current study it was our aim to prepare a set of sidechain-modified derivatives and to evaluate their potential to protect the blood-brain barrier (BBB) from oxidative stress. Six novel ecdysteroids, including an oxime and five oxime ethers, were obtained through regioselective synthesis from a sidechain-cleaved calonysterone derivative 2 and fully characterized by comprehensive NMR techniques revealing their complete 1H and 13C signal assignments. Surprisingly, several compounds sensitized hCMEC/D3 brain microvascular endothelial cells to tert-butyl hydroperoxide (tBHP)-induced oxidative damage as recorded by impedance measurements. Compound 8, containing a benzyloxime ether moiety in its sidechain, was the only one that exerted a protective effect at a higher, 10 μM concentration, while at lower (10 nM- 1 μM) concentrations it promoted tBHP-induced cellular damage. Brain endothelial cells were protected from tBHP-induced barrier integrity decrease by treatment with 10 μM of compound 8, which also mitigated the intracellular reactive oxygen species production elevated by tBHP. Based on our results, 17-oxime ethers of oxidized ecdysteroids modulate oxidative stress of the BBB in a way that may point towards unexpected toxicity. Further studies are needed to evaluate any possible risk connected to dietary ecdysteroid consumption and CNS pathologies in which BBB damage plays an important role.

Trimethylamine N-Oxide as a Mediator Linking Peripheral to Central Inflammation: An In Vitro Study

In this study, the plausible role of trimethylamine N-oxide (TMAO), a microbiota metabolite, was investigated as a link between peripheral inflammation and the inflammation of the central nervous system using different cell lines. TMAO treatment favored the differentiation of adipocytes from preadipocytes (3T3-L1 cell line). In macrophages (RAW 264.7 cell line), which infiltrate adipose tissue in obesity, TMAO increased the expression of pro-inflammatory cytokines. The treatment with 200 μM of TMAO seemed to disrupt the blood-brain barrier as it induced a significant decrease in the expression of occludin in hCMECs. TMAO also increased the expression of pro-inflammatory cytokines in primary neuronal cultures, induced a pro-inflammatory state in primary microglial cultures, and promoted phagocytosis. Data obtained from this project suggest that microbial dysbiosis and increased TMAO secretion could be a key link between peripheral and central inflammation. Thus, TMAO-decreasing compounds may be a promising therapeutic strategy for neurodegenerative diseases.

Highly Oxidized Ecdysteroids from a Commercial Cyanotis arachnoidea Root Extract as Potent Blood-Brain Barrier Protective Agents

Ecdysteroid-containing herbal extracts, commonly prepared from the roots of Cyanotis arachnoidea, are marketed worldwide as a "green" anabolic food supplement. Herein are reported the isolation and complete 1H and 13C NMR signal assignments of three new minor ecdysteroids (compounds 2-4) from this extract. Compound 4 was identified as a possible artifact that gradually forms through the autoxidation of calonysterone. The compounds tested demonstrated a significant protective effect on the blood-brain barrier endothelial cells against oxidative stress or inflammation at a concentration of 1 μM. Based on these results, minor ecdysteroids present in food supplements may offer health benefits in various neurodegenerative disease states.

Generation of Brain Microvascular Endothelial-like Cells from Human iPS Cell-Derived Endothelial Progenitor Cells Using TGF-β Receptor Inhibitor, Laminin 511 Fragment, and Neuronal Cell Culture Supplements

Brain microvascular endothelial cells (BMECs) constitute the blood-brain barrier (BBB), which prevents the transfer of substances into the brain. Recently, in vitro BBB models using human-induced pluripotent stem (iPS) cell-derived brain microvascular endothelial-like cells (iBMELCs) have been created. However, it is suggested that iBMELCs differentiated by the existing methods are different from the BMECs that occur in vivo. This study aimed to establish iBMELCs generated via human iPS cell-derived endothelial progenitor cells (iEPCs) (E-iBMELCs). Expanded and cryopreserved iEPCs were thawed and differentiated into mature endothelial cells under various conditions. Intercellular barriers were significantly enhanced in E-iBMELCs using a B-27 supplement, transforming growth factor-β receptor inhibitor, and laminin 511 fragment. Expression of the endothelial cell markers was higher in the E-iBMELCs generated in this study compared with conventional methods. In addition, E-iBMELCs expressed P-glycoprotein. E-iBMELCs developed in this study will significantly contribute to drug discovery for neurodegenerative diseases and might elucidate the pathogenesis of neurodegenerative diseases associated with BBB disruption.

Cellular Therapy Using Epitope-Imprinted Composite Nanoparticles to Remove α-Synuclein from an In Vitro Model

Several degenerative disorders of the central nervous system, including Parkinson’s disease (PD), are related to the pathological aggregation of proteins. Antibodies against toxic disease proteins, such as α-synuclein (SNCA), are therefore being developed as possible therapeutics. In this work, one peptide (YVGSKTKEGVVHGVA) from SNCA was used as the epitope to construct magnetic molecularly imprinted composite nanoparticles (MMIPs). These composite nanoparticles were characterized by dynamic light scattering (DLS), high-performance liquid chromatography (HPLC), isothermal titration calorimetry (ITC), Brunauer–Emmett–Teller (BET) analysis, and superconducting quantum interference device (SQUID) analysis. Finally, the viability of brain endothelial cells that were treated with MMIPs was measured, and the extraction of SNCA from CRISPR/dCas9a-activated HEK293T cells from the in vitro model system was demonstrated for the therapeutic application of MMIPs.

Novel cyclic C5-curcuminoids penetrating the blood-brain barrier: Design, synthesis and antiproliferative activity against astrocytoma and neuroblastoma cells

Novel series of cyclic C₅-curcuminoids 17a-j and 19-22 were prepared as cytotoxic agents and evaluated against human neuroblastoma (SH-SY5Y) or human grade IV astrocytoma (CCF-STTG1) cell lines in low (∼0.1 nM - 10 nM) concentrations. Among the tested 21 derivatives, 16 displayed potent antiproliferative activity with IC₅₀ values in the low nanomolar to picomolar range (IC₅₀ = 7.483-0.139 nM). Highly active compounds like N-monocarboxylic derivative 19b with IC₅₀ = 0.139 nM value against neuroblastoma and N-alkyl substituted 11 with IC₅₀ = 0.257 nM against astrocytoma proved some degree of selectivity toward non-cancerous astrocytes and kidney cells. This potent anticancer activity did not show a strong correlation with experimental logP_TLC values, but the most potent antiproliferative molecules 11-13 and 19-22 are belonging to discrete subgroups of the cyclic C₅-curcuminoids. Compounds 12, 17c and 19b were subjected to blood-brain barrier (BBB) penetration studies, too. The BBB was revealed to be permeable for all of them but, as the apparent permeability coefficient (P_app) values mirrored, in different ratios. Lower toxicity of 12, 17c and 19b was observed toward primary rat brain endothelial cells of the BBB model, which means they remained undamaged under 10 µM concentrations. Penetration depends, at least in part, on albumin binding of 12, 17c and 19b and the presence of monocarboxylic acid transporters in the case of 19b. Permeation through the BBB and albumin binding, we described here, is the first example of cyclic C₅-curcuminoids as to our knowledge.

Blood-brain barrier dysfunction in L-ornithine induced acute pancreatitis in rats and the direct effect of L-ornithine on cultured brain endothelial cells

BACKGROUND

In severe acute pancreatitis (AP) the CNS is affected manifesting in neurological symptoms. Earlier research from our laboratory showed blood-brain barrier (BBB) permeability elevation in a taurocholate-induced AP model. Here we aimed to further explore BBB changes in AP using a different, non-invasive in vivo model induced by L-ornithine. Our goal was also to identify whether L-ornithine, a cationic amino acid, has a direct effect on brain endothelial cells in vitro contributing to the observed BBB changes.

METHODS

AP was induced in rats by the intraperitoneal administration of L-ornithine-HCl. Vessel permeability and the gene expression of the primary transporter of L-ornithine, cationic amino acid transporter-1 (Cat-1) in the brain cortex, pancreas, liver and lung were determined. Ultrastructural changes were followed by transmission electron microscopy. The direct effect of L-ornithine was tested on primary rat brain endothelial cells and a triple co-culture model of the BBB. Viability and barrier integrity, including permeability and TEER, nitrogen monoxide (NO) and reactive oxygen species (ROS) production and NF-κB translocation were measured. Fluorescent staining for claudin-5, occludin, ZO-1, β-catenin, cell adhesion molecules Icam-1 and Vcam-1 and mitochondria was performed. Cell surface charge was measured by laser Doppler velocimetry.

RESULTS

In the L-ornithine-induced AP model vessel permeability for fluorescein and Cat-1 expression levels were elevated in the brain cortex and pancreas. On the ultrastructural level surface glycocalyx and mitochondrial damage, tight junction and basal membrane alterations, and glial edema were observed. L-ornithine decreased cell impedance and elevated the BBB model permeability in vitro. Discontinuity in the surface glycocalyx labeling and immunostaining of junctional proteins, cytoplasmic redistribution of ZO-1 and β-catenin, and elevation of Vcam-1 expression were measured. ROS production was increased and mitochondrial network was damaged without NF-κB, NO production or mitochondrial membrane potential alterations. Similar ultrastructural changes were seen in L-ornithine treated brain endothelial cells as in vivo. The basal negative zeta potential of brain endothelial cells became more positive after L-ornithine treatment.

CONCLUSION

We demonstrated BBB damage in the L-ornithine-induced rat AP model suggesting a general, AP model independent effect. L-ornithine induced oxidative stress, decreased barrier integrity and altered BBB morphology in a culture BBB model. These data suggest a direct effect of the cationic L-ornithine on brain endothelium. Endothelial surface glycocalyx injury was revealed both in vivo and in vitro, as an additional novel component of the BBB-related pathological changes in AP.

A Triple Combination of Targeting Ligands Increases the Penetration of Nanoparticles across a Blood-Brain Barrier Culture Model

Nanosized drug delivery systems targeting transporters of the blood-brain barrier (BBB) are promising carriers to enhance the penetration of therapeutics into the brain. The expression of solute carriers (SLC) is high and shows a specific pattern at the BBB. Here we show that targeting ligands ascorbic acid, leucine and glutathione on nanoparticles elevated the uptake of albumin cargo in cultured primary rat brain endothelial cells. Moreover, we demonstrated the ability of the triple-targeted nanovesicles to deliver their cargo into midbrain organoids after crossing the BBB model. The cellular uptake was temperature- and energy-dependent based on metabolic inhibition. The process was decreased by filipin and cytochalasin D, indicating that the cellular uptake of nanoparticles was partially mediated by endocytosis. The uptake of the cargo encapsulated in triple-targeted nanoparticles increased after modification of the negative zeta potential of endothelial cells by treatment with a cationic lipid or after cleaving the glycocalyx with an enzyme. We revealed that targeted nanoparticles elevated plasma membrane fluidity, indicating the fusion of nanovesicles with endothelial cell membranes. Our data indicate that labeling nanoparticles with three different ligands of multiple transporters of brain endothelial cells can promote the transfer and delivery of molecules across the BBB.

Development of In Situ Gelling Meloxicam-Human Serum Albumin Nanoparticle Formulation for Nose-to-Brain Application

The aim of this study was to develop an intranasal in situ thermo-gelling meloxicam-human serum albumin (MEL-HSA) nanoparticulate formulation applying poloxamer 407 (P407), which can be administered in liquid state into the nostril, and to increase the resistance of the formulation against mucociliary clearance by sol-gel transition on the nasal mucosa, as well as to improve drug absorption. Nanoparticle characterization showed that formulations containing 12-15% w/w P407 met the requirements of intranasal administration. The Z-average (in the range of 180-304 nm), the narrow polydispersity index (PdI, from 0.193 to 0.328), the zeta potential (between -9.4 and -7.0 mV) and the hypotonic osmolality (200-278 mOsmol/L) of MEL-HSA nanoparticles predict enhanced drug absorption through the nasal mucosa. Based on the rheological, muco-adhesion, drug release and permeability studies, the 14% w/w P407 containing formulation (MEL-HSA-P14%) was considered as the optimized formulation, which allows enhanced permeability of MEL through blood-brain barrier-specific lipid fraction. Cell line studies showed no cell damage after 1-h treatment with MEL-HSA-P14% on RPMI 2650 human endothelial cells' moreover, enhanced permeation (four-fold) of MEL from MEL-HSA-P14% was observed in comparison to pure MEL. Overall, MEL-HSA-P14% can be promising for overcoming the challenges of nasal drug delivery.

Neuroinflammatory processes are augmented in mice overexpressing human heat-shock protein B1 following ethanol-induced brain injury

Background

Heat-shock protein B1 (HSPB1) is among the most well-known and versatile member of the evolutionarily conserved family of small heat-shock proteins. It has been implicated to serve a neuroprotective role against various neurological disorders via its modulatory activity on inflammation, yet its exact role in neuroinflammation is poorly understood. In order to shed light on the exact mechanism of inflammation modulation by HSPB1, we investigated the effect of HSPB1 on neuroinflammatory processes in an in vivo and in vitro model of acute brain injury.

Methods

In this study, we used a transgenic mouse strain overexpressing the human HSPB1 protein. In the in vivo experiments, 7-day-old transgenic and wild-type mice were treated with ethanol. Apoptotic cells were detected using TUNEL assay. The mRNA and protein levels of cytokines and glial cell markers were examined using RT-PCR and immunohistochemistry in the brain. We also established primary neuronal, astrocyte, and microglial cultures which were subjected to cytokine and ethanol treatments. TNFα and hHSPB1 levels were measured from the supernates by ELISA, and intracellular hHSPB1 expression was analyzed using fluorescent immunohistochemistry.

Results

Following ethanol treatment, the brains of hHSPB1-overexpressing mice showed a significantly higher mRNA level of pro-inflammatory cytokines (Tnf, Il1b), microglia (Cd68, Arg1), and astrocyte (Gfap) markers compared to wild-type brains. Microglial activation, and 1 week later, reactive astrogliosis was higher in certain brain areas of ethanol-treated transgenic mice compared to those of wild-types. Despite the remarkably high expression of pro-apoptotic Tnf, hHSPB1-overexpressing mice did not exhibit higher level of apoptosis. Our data suggest that intracellular hHSPB1, showing the highest level in primary astrocytes, was responsible for the inflammation-regulating effects. Microglia cells were the main source of TNFα in our model. Microglia isolated from hHSPB1-overexpressing mice showed a significantly higher release of TNFα compared to wild-type cells under inflammatory conditions.

Conclusions

Our work provides novel in vivo evidence that hHSPB1 overexpression has a regulating effect on acute neuroinflammation by intensifying the expression of pro-inflammatory cytokines and enhancing glial cell activation, but not increasing neuronal apoptosis. These results suggest that hHSPB1 may play a complex role in the modulation of the ethanol-induced neuroinflammatory response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02070-2.

Hydroxyethylstarch revisited for acute brain injury treatment

Infusion of the colloid hydroxyethylstarch has been used for volume substitution to maintain hemodynamics and microcirculation after e.g., severe blood loss. In the last decade it was revealed that hydroxyethylstarch can aggravate acute kidney injury, especially in septic patients. Because of the serious risk for critically ill patients, the administration of hydroxyethylstarch was restricted for clinical use. Animal studies and recently published in vitro experiments showed that hydroxyethylstarch might exert protective effects on the blood-brain barrier. Since the prevention of blood-brain barrier disruption was shown to go along with the reduction of brain damage after several kinds of insults, we revisit the topic hydroxyethylstarch and discuss a possible niche for the application of hydroxyethylstarch in acute brain injury treatment.

Activation of Melanocortin Receptors as a Potential Strategy to Reduce Local and Systemic Reactions Induced by Respiratory Viruses

The clinical hallmarks of infections caused by critical respiratory viruses consist of pneumonia, which can progress to acute lung injury (ALI), and systemic manifestations including hypercoagulopathy, vascular dysfunction, and endotheliitis. The disease outcome largely depends on the immune response produced by the host. The bio-molecular mechanisms underlying certain dire consequences of the infection partly arise from an aberrant production of inflammatory molecules, an event denoted as "cytokine storm". Therefore, in addition to antiviral therapies, molecules able to prevent the injury caused by cytokine excess are under investigation. In this perspective, taking advantage of melanocortin peptides and their receptors, components of an endogenous modulatory system that exerts marked anti-inflammatory and immunomodulatory influences, could be an effective therapeutic strategy to control disease evolution. Exploiting the melanocortin system using natural or synthetic ligands can form a realistic basis to counteract certain deleterious effects of respiratory virus infections. The central and peripheral protective actions exerted following melanocortin receptor activation could allow dampening the harmful events that trigger the cytokine storm and endothelial dysfunction while sustaining the beneficial signals required to elicit repair mechanisms. The long standing evidence for melanocortin safety encourages this approach.

Concussive head injury exacerbates neuropathology of sleep deprivation: Superior neuroprotection by co-administration of TiO2-nanowired cerebrolysin, alpha-melanocyte-stimulating hormone, and mesenchymal stem cells

Sleep deprivation (SD) is common in military personnel engaged in combat operations leading to brain dysfunction. Military personnel during acute or chronic SD often prone to traumatic brain injury (TBI) indicating the possibility of further exacerbating brain pathology. Several lines of evidence suggest that in both TBI and SD alpha-melanocyte-stimulating hormone (α-MSH) and brain-derived neurotrophic factor (BDNF) levels decreases in plasma and brain. Thus, a possibility exists that exogenous supplement of α-MSH and/or BDNF induces neuroprotection in SD compounded with TBI. In addition, mesenchymal stem cells (MSCs) are very portent in inducing neuroprotection in TBI. We examined the effects of concussive head injury (CHI) in SD on brain pathology. Furthermore, possible neuroprotective effects of α-MSH, MSCs and neurotrophic factors treatment were explored in a rat model of SD and CHI. Rats subjected to 48h SD with CHI exhibited higher leakage of BBB to Evans blue and radioiodine compared to identical SD or CHI alone. Brain pathology was also exacerbated in SD with CHI group as compared to SD or CHI alone together with a significant reduction in α-MSH and BDNF levels in plasma and brain and enhanced level of tumor necrosis factor-alpha (TNF-α). Exogenous administration of α-MSH (250μg/kg) together with MSCs (1×10⁶) and cerebrolysin (a balanced composition of several neurotrophic factors and active peptide fragments) (5mL/kg) significantly induced neuroprotection in SD with CHI. Interestingly, TiO₂ nanowired delivery of α-MSH (100μg), MSCs, and cerebrolysin (2.5mL/kg) induced enhanced neuroprotection with higher levels of α-MSH and BDNF and decreased the TNF-α in SD with CHI. These observations are the first to show that TiO₂ nanowired administration of α-MSH, MSCs and cerebrolysin induces superior neuroprotection following SD in CHI, not reported earlier. The clinical significance of our findings in light of the current literature is discussed.

Metabolomics Reveals the Alteration of Metabolic Pathway by Alpha-Melanocyte-Stimulating Hormone in B16F10 Melanoma Cells

The purpose of this study was to understand the changes of metabolic pathway induced by alpha-melanocyte-stimulating hormone (α-MSH) in B16F10 melanoma cells in an untargeted metabolomics approach. Cells were treated with 100 nM of α-MSH and then incubated for 48 h. α-MSH increased tyrosinase activity and melanin content by 56.5 and 61.7%, respectively, compared to untreated cells after 48 h of cultivation. The clear separation between groups was observed in the principal component analysis score plot, indicating that the levels of metabolites of melanoma cells were altered by treatment with α-MSH. Metabolic pathways affected by α-MSH were involved in some amino acid metabolisms. The increased levels of fumaric acid, malic acid, oxaloacetic acid and citric acid related to the citric acid cycle pathway after α-MSH treatment suggested enhanced energy metabolism. Metabolic pathways altered by α-MSH treatment can provide useful information to develop new skin pigmentation inhibitors or anti-obesity drugs.

Development and Characterization of Potential Ocular Mucoadhesive Nano Lipid Carriers Using Full Factorial Design

Generally, topically applied eye drops have low bioavailability due to short residence time and low penetration of the drug. The aim of the present study was to incorporate dexamethasone (DXM) into nano lipid carriers (NLC), which contain mucoadhesive polymer, in order to increase the bioavailability of the drug. A 2³ factorial experimental design was applied, in which the three factors were the polymer, the DXM, and the emulsifier concentrations. The samples were analyzed for particle size, zeta potential, polydispersity index, and Span value. The significant factors were identified. The biocompatibility of the formulations was evaluated with human corneal toxicity tests and immunoassay analysis. The possible increase in bioavailability was analyzed by means of mucoadhesivity, in vitro drug diffusion, and different penetration tests, such as in vitro cornea PAMPA model, human corneal cell penetration, and ex vivo porcine corneal penetration using Raman mapping. The results indicated that DXM can be incorporated in stable mucoadhesive NLC systems, which are non-toxic and do not have any harmful effect on cell junctions. Mucoadhesive NLCs can create a depot on the surface of the cornea, which can predict improved bioavailability.

Combination of Alanine and Glutathione as Targeting Ligands of Nanoparticles Enhances Cargo Delivery into the Cells of the Neurovascular Unit

Inefficient drug delivery across the blood–brain barrier (BBB) and into target cells in the brain hinders the treatment of neurological diseases. One strategy to increase the brain penetration of drugs is to use vesicular nanoparticles functionalized with multiple ligands of BBB transporters as vehicles. Once within the brain, however, drugs must also be able to reach their therapeutic targets in the different cell types. It is, therefore, favorable if such nanocarriers are designed that can deliver their cargo not only to brain endothelial cells, but to other cell types as well. Here, we show that alanine-glutathione dual-targeting of niosomes enhances the delivery of a large protein cargo into cultured cells of the neurovascular unit, namely brain endothelial cells, pericytes, astrocytes and neurons. Furthermore, using metabolic and endocytic inhibitors, we show that the cellular uptake of niosomes is energy-dependent and is partially mediated by endocytosis. Finally, we demonstate the ability of our targeted nanovesicles to deliver their cargo into astroglial cells after crossing the BBB in vitro. These data indicate that dual-labeling of nanoparticles with alanine and glutathione can potentially be exploited to deliver drugs, even biopharmacons, across the BBB and into multiple cell types in the brain.

Cosyntropin Attenuates Neuroinflammation in a Mouse Model of Traumatic Brain Injury

Aim: Traumatic brain injury (TBI) is a leading cause of mortality/morbidity and is associated with chronic neuroinflammation. Melanocortin receptor agonists including adrenocorticotropic hormone (ACTH) ameliorate inflammation and provide a novel therapeutic approach. We examined the effect of long-acting cosyntropin (CoSyn), a synthetic ACTH analog, on the early inflammatory response and functional outcome following experimental TBI.

Methods: The controlled cortical impact model was used to induce TBI in mice. Mice were assigned to injury and treatment protocols resulting in four experimental groups including sham + saline, sham + CoSyn, TBI + saline, and TBI + CoSyn. Treatment was administered subcutaneously 3 h post-injury and daily injections were given for up to 7 days post-injury. The early inflammatory response was evaluated at 3 days post-injury through the evaluation of cytokine expression (IL1β and TNFα) and immune cell response. Quantification of immune cell response included cell counts of microglia/macrophages (Iba1+ cells) and neutrophils (MPO+ cells) in the cortex and hippocampus. Behavioral testing (n = 10–14 animals/group) included open field (OF) and novel object recognition (NOR) during the first week following injury and Morris water maze (MWM) at 10–15 days post-injury.

Results: Immune cell quantification showed decreased accumulation of Iba1+ cells in the perilesional cortex and CA1 region of the hippocampus for CoSyn-treated TBI animals compared to saline-treated. Reduced numbers of MPO+ cells were also found in the perilesional cortex and hippocampus in CoSyn treated TBI mice compared to their saline-treated counterparts. Furthermore, CoSyn treatment reduced IL1β expression in the cortex of TBI mice. Behavioral testing showed a treatment effect of CoSyn for NOR with CoSyn increasing the discrimination ratio in both TBI and Sham groups, indicating increased memory performance. CoSyn also decreased latency to find platform during the early training period of the MWM when comparing CoSyn to saline-treated TBI mice suggesting moderate improvements in spatial memory following CoSyn treatment.

Conclusion: Reduced microglia/macrophage accumulation and neutrophil infiltration in conjunction with moderate improvements in spatial learning in our CoSyn treated TBI mice suggests a beneficial anti-inflammatory effect of CoSyn following TBI.

The Effect of Sodium Bicarbonate, a Beneficial Adjuvant Molecule in Cystic Fibrosis, on Bronchial Epithelial Cells Expressing a Wild-Type or Mutant CFTR Channel

Clinical and experimental results with inhaled sodium bicarbonate as an adjuvant therapy in cystic fibrosis (CF) are promising due to its mucolytic and bacteriostatic properties, but its direct effect has not been studied on respiratory epithelial cells. Our aim was to establish and characterize co-culture models of human CF bronchial epithelial (CFBE) cell lines expressing a wild-type (WT) or mutant (deltaF508) CF transmembrane conductance regulator (CFTR) channel with human vascular endothelial cells and investigate the effects of bicarbonate. Vascular endothelial cells induced better barrier properties in CFBE cells as reflected by the higher resistance and lower permeability values. Activation of CFTR by cAMP decreased the electrical resistance in WT but not in mutant CFBE cell layers confirming the presence and absence of functional channels, respectively. Sodium bicarbonate (100 mM) was well-tolerated by CFBE cells: it slightly reduced the impedance of WT but not that of the mutant CFBE cells. Sodium bicarbonate significantly decreased the more-alkaline intracellular pH of the mutant CFBE cells, while the barrier properties of the models were only minimally changed. These observations indicate that sodium bicarbonate is beneficial to deltaF508-CFTR expressing CFBE cells. Thus, sodium bicarbonate may have a direct therapeutic effect on the bronchial epithelium.

In vitro modeling of blood-brain barrier and interface functions in neuroimmune communication

Neuroimmune communication contributes to both baseline and adaptive physiological functions, as well as disease states. The vascular blood-brain barrier (BBB) and associated cells of the neurovascular unit (NVU) serve as an important interface for immune communication between the brain and periphery through the blood. Immune functions and interactions of the BBB and NVU in this context can be categorized into at least five neuroimmune axes, which include (1) immune modulation of BBB impermeability, (2) immune regulation of BBB transporters, secretions, and other functions, (3) BBB uptake and transport of immunoactive substances, (4) immune cell trafficking, and (5) BBB secretions of immunoactive substances. These axes may act separately or in concert to mediate various aspects of immune signaling at the BBB. Much of what we understand about immune axes has been from work conducted using in vitro BBB models, and recent advances in BBB and NVU modeling highlight the potential of these newer models for improving our understanding of how the brain and immune system communicate. In this review, we discuss how conventional in vitro models of the BBB have improved our understanding of the 5 neuroimmune axes. We further evaluate the existing literature on neuroimmune functions of novel in vitro BBB models, such as those derived from human induced pluripotent stem cells (iPSCs) and discuss their utility in evaluating aspects of neuroimmune communication.

Simvastatin, edaravone and dexamethasone protect against kainate-induced brain endothelial cell damage

BACKGROUND

Excitotoxicity is a central pathological pathway in many neurological diseases with blood-brain barrier (BBB) dysfunction. Kainate, an exogenous excitotoxin, induces epilepsy and BBB damage in animal models, but the direct effect of kainate on brain endothelial cells has not been studied in detail. Our aim was to examine the direct effects of kainate on cultured cells of the BBB and to test three anti-inflammatory and antioxidant drugs used in clinical practice, simvastatin, edaravone and dexamethasone, to protect against kainate-induced changes.

METHODS

Primary rat brain endothelial cell, pericyte and astroglia cultures were used to study cell viability by impedance measurement. BBB permeability was measured on a model made from the co-culture of the three cell types. The production of nitrogen monoxide and reactive oxygen species was followed by fluorescent probes. The mRNA expression of kainate receptors and nitric oxide synthases were studied by PCR.

RESULTS

Kainate damaged brain endothelial cells and made the immunostaining of junctional proteins claudin-5 and zonula occludens-1 discontinuous at the cell border indicating the opening of the barrier. The permeability of the BBB model for marker molecules fluorescein and albumin and the production of nitric oxide in brain endothelial cells were increased by kainate. Simvastatin, edaravone and dexamethasone protected against the reduced cell viability, increased permeability and the morphological changes in cellular junctions caused by kainate. Dexamethasone attenuated the elevated nitric oxide production and decreased the inducible nitric oxide synthase (NOS2/iNOS) mRNA expression increased by kainate treatment.

CONCLUSION

Kainate directly damaged cultured brain endothelial cells. Simvastatin, edaravone and dexamethasone protected the BBB model against kainate-induced changes. Our results confirmed the potential clinical usefulness of these drugs to attenuate BBB damage.

The effects of Vitis vinifera L. phenolic compounds on a blood-brain barrier culture model: Expression of leptin receptors and protection against cytokine-induced damage

ETHNOPHARMACOLOGICAL RELEVANCE

The medicinal properties of grapes (Vitis vinifera L.) are well known since ancient times. Ethnobotanical grape preparations, like the Ayurvedic Darakchasava are used as cardiotonic and for the treatment of cardiovascular diseases. Dried grape products are also applied in Iranian traditional medicine for memory problems, which are linked to the pathology of brain microvessels, a special part of the cardiovascular system. The anti-inflammatory and protective effects of these traditional preparations on the cardiovascular system are related to their bioactive phenolic compounds.

AIM OF THE STUDY

The blood-brain barrier (BBB), formed by brain capillaries, is not only involved in inflammatory and other diseases of the central nervous system, but also in many systemic diseases with an inflammatory component. Dietary obesity is a systemic chronic inflammatory condition in which the peripheral and central vascular system is affected. Among the cerebrovascular changes in obesity defective leptin transport across the BBB related to central leptin resistance is observed. Our aim was to study the protective effects of grape phenolic compounds epicatechin (EC), gallic acid (GA) and resveratrol (RSV) and grape-seed proanthocyanidin-rich extract (GSPE) on a cytokine-induced vascular endothelial inflammation model. Using a culture model of the BBB we investigated cytokine-induced endothelial damage and changes in the expression of leptin receptors and leptin transfer.

MATERIALS AND METHODS

For the BBB model, primary cultures of rat brain endothelial cells, glial cells and pericytes were used in co-culture. Cells were treated by tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β) (10 ng/ml each) to induce damage. Cell toxicity was evaluated by the measurement of impedance. The expression of leptin receptors was assessed by RT-qPCR and western blot. The production of reactive oxygen species (ROS) and nitric oxide (NO) were detected by fluorescent probes.

RESULTS

GSPE (10 μg/ml), EC (10 μM), GA (1 μM) or RSV (10 μM) did not change the viability of brain endothelial cells. The gene expression of the short leptin receptor isoform, Ob-Ra, was up-regulated by GSPE, EC and RSV, while the mRNA levels of Lrp2 and clusterin, clu/ApoJ were not affected. The tested compounds did not change the expression of the long leptin receptor isoform, Ob-Rb. RSV protected against the cytokine-induced increase in albumin permeability of the BBB model. GSPE and EC exerted an antioxidant effect and GSPE increased NO both alone and in the presence of cytokines. The cytokine-induced nuclear translocation of transcription factor NF-κB was blocked by GSPE, GA and RSV. Cytokines increased the mRNA expression of Lrp2 which was inhibited by EC. RSV increased Ob-Ra and Clu in the presence of cytokines. Cytokines elevated leptin transfer across the BBB model, which was not modified by GSPE or RSV.

CONCLUSION

Our results obtained on cell culture models confirm that natural grape compounds protect vascular endothelial cells against inflammatory damage in accordance with the ethnopharmacological use of grape preparations in cardiovascular diseases. Furthermore, grape compounds and GSPE, by exerting a beneficial effect on the BBB, may also be considered in the treatment of obesity after validation in clinical trials.

Hydroxyethylstarch (130/0.4) tightens the blood-brain barrier in vitro

In order to prevent cerebral vasospasm after a subarachnoid hemorrhage (SAH), the so-called triple H-therapy (hypertension, hypervolemia, hemodilution) could be applied. In these cases, colloidal solutions containing Hydroxyethylstarch (HES) are used to induce hypervolemia. The administration of HES is very much under debate for the mentioned use, because in general the application of HES for the treatment of critical ill patients has been reduced tremendously in the last years due to its nephrotoxic effects. In this context, there are limited data investigating the influence of HES on the blood-brain barrier. These data might help to assess if a transient administration of HES is possibly justifiable to prevent cerebral ischemia during vasospasm despite the risk of an acute kidney injury. To address this question, a mouse blood-brain barrier in vitro model based on cell line cerebEND was exposed to different HES concentrations and compared to NaCl-containing control solutions. In order to assess the effects of HES on blood-brain barrier properties, cell viability, transendothelial electrical resistance, permeability of carboxyfluorescein, mRNA and protein expression and localization of tight junction proteins were determined. In summary, 1.5-4% HES attenuated cell viability in a mild, concentration dependent manner compared to the NaCl control solution (0% HES). At the mRNA level 1% and 4% HES significantly increased the expression of tight junction associated proteins (ZO-1 and occludin) and the glucose transporter Glut-1 (Slc2a1). In correspondence to this, 4% HES inhibited breakdown of the paracellular barrier in comparison to the control NaCl group (0% HES) shown by transendothelial electrical resistance values and the permeability of the paracellular marker carboxyfluorescein. These effects at the functional level were confirmed by immunofluorescence microscopic images of junctional proteins. The obtained in vitro data showed a potential for HES to counteract blood-brain barrier damage. Future studies are needed to reveal the applicability of HES as a blood-brain barrier stabilizing agent.