TY - JOUR A1 - Shityakov, Sergey A1 - Sohajda, Tamás A1 - Puskas, Istaván A1 - Roewer, Norbert A1 - Förster, Carola A1 - Broscheit, Jens-Albert T1 - Ionization States, Cellular Toxicity and Molecular Modeling Studies of Midazolam Complexed with Trimethyl-β-Cyclodextrin JF - Molecules N2 - We investigated the ionization profiles for open-ring (OR) and closed-ring (CR) forms of midazolam and drug-binding modes with heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (trimethyl-β-cyclodextrin; TRIMEB) using molecular modeling techniques and quantum mechanics methods. The results indicated that the total net charges for different molecular forms of midazolam tend to be cationic for OR and neutral for CR at physiological pH levels. The thermodynamic calculations demonstrated that CR is less water-soluble than OR, mainly due to the maximal solvation energy (ΔG(CR)(solv = -9.98 kcal·mol ⁻¹), which has a minimal ΔG(OR)(solv) of -67.01 kcal·mol⁻¹. A cell viability assay did not detect any signs of TRIMEB and OR/CR-TRIMEB complex toxicity on the cEND cells after 24 h of incubation in either Dulbecco's Modified Eagles Medium or in heat-inactivated human serum. The molecular docking studies identified the more flexible OR form of midazolam as being a better binder to TRIMEB with the fluorophenyl ring introduced inside the amphiphilic cavity of the host molecule. The OR binding affinity was confirmed by a minimal Gibbs free energy of binding (ΔG(bind)) value of -5.57 ± 0.02 kcal·mol⁻¹, an equilibrium binding constant (K(b)) of 79.89 ± 2.706 μM, and a ligand efficiency index (LE(lig)) of -0.21 ± 0.001. Our current data suggest that in order to improve the clinical applications of midazolam via its complexation with trimethyl-β-cyclodextrin to increase drug's overall aqueous solubility, it is important to concern the different forms and ionization states of this anesthetic. All mean values are indicated with their standard deviations. KW - quantum mechanics KW - free energy of solvation KW - torsional energy KW - trimethyl-β-cyclodextrin KW - midazolam KW - transition state KW - molecular docking KW - Gibbs free energy of binding Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119186 VL - 19 IS - 10 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Salvador, Ellaine A1 - Pastorin, Giorgia A1 - Förster, Carola T1 - Blood-brain barrier transport studies, aggregation, and molecular dynamics simulation of multiwalled carbon nanotube functionalized with fluorescein isothiocyanate JF - International Journal of Nanomedicine N2 - In this study, the ability of a multiwalled carbon nanotube functionalized with fluorescein isothiocyanate (MWCNT-FITC) was assessed as a prospective central nervous system-targeting drug delivery system to permeate the blood-brain barrier. The results indicated that the MWCNT-FITC conjugate is able to penetrate microvascular cerebral endothelial monolayers; its concentrations in the Transwell® system were fully equilibrated after 48 hours. Cell viability test, together with phase-contrast and fluorescence microscopies, did not detect any signs of MWCNT-FITC toxicity on the cerebral endothelial cells. These microscopic techniques also revealed presumably the intracellular localization of fluorescent MWCNT-FITCs apart from their massive nonfluorescent accumulation on the cellular surface due to nanotube lipophilic properties. In addition, the 1,000 ps molecular dynamics simulation in vacuo discovered the phenomenon of carbon nanotube aggregation driven by van der Waals forces via MWCN-TFITC rapid dissociation as an intermediate phase. KW - endothelial cells KW - cytotoxicity KW - blood-brain barrier KW - fluorescein isothiocyanate KW - aggregation KW - molecular dynamics KW - fluorescence microscopy KW - Transwell® system KW - multiwalled carbon nanotube KW - mice Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149233 VL - 10 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Roewer, Norbert A1 - Förster, Carola A1 - Broscheit, Jens-Albert T1 - In silico modeling of indigo and Tyrian purple single-electron nano-transistors using density functional theory approach JF - Nanoscale Research Letters N2 - The purpose of this study was to develop and implement an in silico model of indigoid-based single-electron transistor (SET) nanodevices, which consist of indigoid molecules from natural dye weakly coupled to gold electrodes that function in a Coulomb blockade regime. The electronic properties of the indigoid molecules were investigated using the optimized density-functional theory (DFT) with a continuum model. Higher electron transport characteristics were determined for Tyrian purple, consistent with experimentally derived data. Overall, these results can be used to correctly predict and emphasize the electron transport functions of organic SETs, demonstrating their potential for sustainable nanoelectronics comprising the biodegradable and biocompatible materials. KW - density functional theory KW - indigo KW - Tyrian purple KW - single-electron transistor Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158332 VL - 12 IS - 439 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Puskás, István A1 - Roewer, Norbert A1 - Förster, Carola A1 - Broscheit, Jens T1 - Three-dimensional quantitative structure-activity relationship and docking studies in a series of anthocyanin derivatives as cytochrome P450 3A4 inhibitors JF - Advances and Applications in Bioinformatics and Chemistry N2 - The cytochrome P450 (CYP)3A4 enzyme affects the metabolism of most drug-like substances, and its inhibition may influence drug safety. Modulation of CYP3A4 by flavonoids, such as anthocyanins, has been shown to inhibit the mutagenic activity of mammalian cells. Considering the previous investigations addressing CYP3A4 inhibition by these substances, we studied the three-dimensional quantitative structure-activity relationship (3D-QSAR) in a series of anthocyanin derivatives as CYP3A4 inhibitors. For the training dataset (n=12), comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) yielded crossvalidated and non-crossvalidated models with a q (2) of 0.795 (0.687) and r (2) of 0.962 (0.948), respectively. The models were also validated by an external test set of four compounds with r (2) of 0.821 (CoMFA) and r (2) of 0.812 (CoMSIA). The binding affinity modes associated with experimentally derived IC50 (half maximal inhibitory concentration) values were confirmed by molecular docking into the CYP3A4 active site with r (2) of 0.66. The results obtained from this study are useful for a better understanding of the effects of anthocyanin derivatives on inhibition of carcinogen activation and cellular DNA damage. KW - molecular docking KW - three-dimensional quantitative structure–activity relationship KW - cytochrome P450 3A4 KW - comparative molecular similarity index analysis KW - comparative molecular field analysis KW - carcinogen activation KW - anthocyanin derivatives Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120226 VL - 7 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Puskás, István A1 - Pápai, Katalin A1 - Salvador, Ellaine A1 - Roewer, Norbert A1 - Förster, Carola A1 - Broscheit, Jens-Albert T1 - Sevoflurane-sulfobutylether-\(\beta\)-cyclodextrin complex: preparation, characterization, cellular toxicity, molecular modeling and blood-brain barrier transport studies JF - Molecules N2 - The objective of the present investigation was to study the ability of sulfobutylether-\(\beta\)-cyclodextrin (SBECD) to form an inclusion complex with sevoflurane (SEV), a volatile anesthetic with poor water solubility. The inclusion complex was prepared, characterized and its cellular toxicity and blood-brain barrier (BBB) permeation potential of the formulated SEV have also been examined for the purpose of controlled drug delivery. The SEV-SBE\(\beta\)CD complex was nontoxic to the primary brain microvascular endothelial (pEND) cells at a clinically relevant concentration of sevoflurane. The inclusion complex exhibited significantly higher BBB permeation profiles as compared with the reference substance (propranolol) concerning calculated apparent permeability values (P\(_{app}\)). In addition, SEV binding affinity to SBE\(\beta\)CD was confirmed by a minimal Gibbs free energy of binding (ΔG\(_{bind}\)) value of -1.727 ± 0.042 kcal・mol\(^{-1}\) and an average binding constant (K\(_{b}\)) of 53.66 ± 9.24 mM indicating rapid drug liberation from the cyclodextrin amphiphilic cavity. KW - pharmaceutical applications KW - in vitro KW - propranolol KW - water KW - primary microvascular endothelial cells KW - molecular liphophilicity potential KW - molecular docking KW - blood-brain barrier KW - ulfobutylether-\(\beta\)-cyclodextrin KW - sevoflurane KW - cyclodextrin formulations KW - safety KW - etomidate KW - formulations KW - hydrochloride KW - ether KW - intestinal absorption Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148543 VL - 20 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Förster, Carola A1 - Rethwilm, Axel A1 - Dandekar, Thomas T1 - Evaluation and Prediction of the HIV-1 Central Polypurine Tract Influence on Foamy Viral Vectors to Transduce Dividing and Growth-Arrested Cells N2 - Retroviral vectors are potent tools for gene delivery and various biomedical applications. To accomplish a gene transfer task successfully, retroviral vectors must effectively transduce diverse cell cultures at different phases of a cell cycle. However, very promising retroviral vectors based on the foamy viral (FV) backbone lack the capacity to efficiently transduce quiescent cells. It is hypothesized that this phenomenon might be explained as the inability of foamy viruses to form a pre-integration complex (PIC) with nuclear import activity in growth-arrested cells, which is the characteristic for lentiviruses (HIV-1). In this process, the HIV-1 central polypurine tract (cPPT) serves as a primer for plus-strand synthesis to produce a “flap” element and is believed to be crucial for the subsequent double-stranded cDNA formation of all retroviral RNA genomes. In this study, the effects of the lentiviral cPPT element on the FV transduction potential in dividing and growth-arrested (G1/S phase) adenocarcinomic human alveolar basal epithelial (A549) cells are investigated by experimental and theoretical methods. The results indicated that the HIV-1 cPPT element in a foamy viral vector background will lead to a significant reduction of the FV transduction and viral titre in growth-arrested cells due to the absence of PICs with nuclear import activity. KW - Evaluation KW - Prognose KW - HIV KW - Spumaviren KW - Einfluss Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112763 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Förster, Carola T1 - In silico predictive model to determine vector-mediated transport properties for the blood-brain barrier choline transporter JF - Advances and Applications in Bioinformatics and Chemistry N2 - The blood–brain barrier choline transporter (BBB-ChT) may have utility as a drug delivery vector to the central nervous system (CNS). We therefore initiated molecular docking studies with the AutoDock and AutoDock Vina (ADVina) algorithms to develop predictive models for compound screening and to identify structural features important for binding to this transporter. The binding energy predictions were highly correlated with r2=0.88, F=692.4, standard error of estimate =0.775, and P-value<0.0001 for selected BBB-ChT-active/inactive compounds (n=93). Both programs were able to cluster active (Gibbs free energy of binding <−6.0 kcal*mol-1) and inactive (Gibbs free energy of binding >−6.0 kcal*mol-1) molecules and dock them significantly better than at random with an area under the curve value of 0.86 and 0.84, respectively. In ranking smaller molecules with few torsional bonds, a size-related bias in scoring producing false-negative outcomes was detected. Finally, important blood–brain barrier parameters, such as the logBBpassive and logBBactive values, were assessed to predict compound transport to the CNS accurately. Knowledge gained from this study is useful to better understand the binding requirements in BBB-ChT, and until such time as its crystal structure becomes available, it may have significant utility in developing a highly predictive model for the rational design of drug-like compounds targeted to the brain. KW - virtual screening KW - Gibbs free energy of binding KW - diffusion KW - molecular docking KW - drug delivery vector KW - central nervous system KW - blood–brain barrier choline transporter Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120200 VL - 7 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Förster, Carola T1 - In silico structure-based screening of versatile P-glycoprotein inhibitors using polynomial empirical scoring functions JF - Advances and Applications in Bioinformatics and Chemistry N2 - P-glycoprotein (P-gp) is an ATP (adenosine triphosphate)-binding cassette transporter that causes multidrug resistance of various chemotherapeutic substances by active efflux from mammalian cells. P-gp plays a pivotal role in limiting drug absorption and distribution in different organs, including the intestines and brain. Thus, the prediction of P-gp–drug interactions is of vital importance in assessing drug pharmacokinetic and pharmacodynamic properties. To find the strongest P-gp blockers, we performed an in silico structure-based screening of P-gp inhibitor library (1,300 molecules) by the gradient optimization method, using polynomial empirical scoring (POLSCORE) functions. We report a strong correlation (r2=0.80, F=16.27, n=6, P<0.0157) of inhibition constants (Kiexp or pKiexp; experimental Ki or negative decimal logarithm of Kiexp) converted from experimental IC50 (half maximal inhibitory concentration) values with POLSCORE-predicted constants (KiPOLSCORE or pKiPOLSCORE), using a linear regression fitting technique. The hydrophobic interactions between P-gp and selected drug substances were detected as the main forces responsible for the inhibition effect. The results showed that this scoring technique might be useful in the virtual screening and filtering of databases of drug-like compounds at the early stage of drug development processes. KW - multidrug resistance KW - molecular docking KW - POLSCORE KW - P-gp inhibitors KW - ATP-binding cassette transporter Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120214 VL - 7 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Förster, Carola T1 - Pharmacokinetic Delivery and Metabolizing Rate of Nicardipine Incorporated in Hydrophilic and Hydrophobic Cyclodextrins Using Two-Compartment Mathematical Model JF - The Scientific World Journal N2 - The dispersion routes of cyclodextrin complexes with nicardipine (NC), such as hydrophilic hydroxypropyl-\(\beta\)-cyclodextrin (NC/HP\(\beta\)CD) and hydrophobic triacetyl-\(\beta\)-cyclodextrin (NC/TA\(\beta\)CD), through the body for controlled drug delivery and sustained release have been examined. The two-compartment pharmacokinetic model described the mechanisms of how the human body handles with ingestion of NC-cyclodextrin complexes in gastrointestinal tract (GI), distribution in plasma, and their metabolism in the liver. The model showed that drug bioavailability was significantly improved after oral administration of cyclodextrin complexes. The mathematical significance of this study to predict nicardipine delivery using pharmacokinetic two-compartment mathematical model with linear ordinary differential equations (ODE) approach represents a valuable tool to emphasize its effectiveness and metabolizing rate and diminish the side effects. KW - pharmacokinetic delivery KW - metabolizing rate KW - Nicardipine Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130519 VL - 2013 IS - 131358 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Dandekar, Thomas A1 - Förster, Carola T1 - Gene expression profiles and protein-protein interaction network analysis in AIDS patients with HIV-associated encephalitis and dementia JF - HIV/AIDS: Research and Palliative Care N2 - Central nervous system dysfunction is an important cause of morbidity and mortality in patients with human immunodeficiency virus type 1 (HIV-1) infection and acquired immunodeficiency virus syndrome (AIDS). Patients with AIDS are usually affected by HIV-associated encephalitis (HIVE) with viral replication limited to cells of monocyte origin. To examine the molecular mechanisms underlying HIVE-induced dementia, the GSE4755 Affymetrix data were obtained from the Gene Expression Omnibus database and the differentially expressed genes (DEGs) between the samples from AIDS patients with and without apparent features of HIVE-induced dementia were identified. In addition, protein–protein interaction networks were constructed by mapping DEGs into protein–protein interaction data to identify the pathways that these DEGs are involved in. The results revealed that the expression of 1,528 DEGs is mainly involved in the immune response, regulation of cell proliferation, cellular response to inflammation, signal transduction, and viral replication cycle. Heat-shock protein alpha, class A member 1 (HSP90AA1), and fibronectin 1 were detected as hub nodes with degree values >130. In conclusion, the results indicate that HSP90A and fibronectin 1 play important roles in HIVE pathogenesis. KW - microarray KW - differentially expressed genes KW - protein-protein interaction network KW - gene ontology KW - encephalitis dementia KW - human immunodeficiency virus Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149494 VL - 7 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Broscheit, Jens A1 - Förster, Carola T1 - Multidrug resistance protein P-gp interaction with nanoparticles (fullerenes and carbon nanotube) to assess their drug delivery potential: a theoretical molecular docking study. JF - International journal of computational biology and drug design N2 - P-glycoprotein (P-gp)-mediated efflux system plays an important role to maintain chemical balance in mammalian cells for endogenous and exogenous chemical compounds. However, despite the extensive characterisation of P-gp potential interaction with drug-like molecules, the interaction of carbon nanoparticles with this type of protein molecule is poorly understood. Thus, carbon nanoparticles were analysed, such as buckminsterfullerenes (C20, C60, C70), capped armchair single-walled carbon nanotube (SWCNT or C168), and P-gp interactions using different molecular docking techniques, such as gradient optimisation algorithm (ADVina), Lamarckian genetic algorithm (FastDock), and shape-based approach (PatchDock) to estimate the binding affinities between these structures. The theoretical results represented in this work show that fullerenes might be P-gp binders because of low levels of Gibbs free energy of binding (ΔG) and potential of mean force (PMF) values. Furthermore, the SWCNT binding is energetically unfavourable, leading to a total decrease in binding affinity by elevation of the residual area (Ares), which also affects the π-π stacking mechanisms. Further, the obtained data could potentially call experimental studies using carbon nanostructures, such as SWCNT for development of drug delivery vehicles, to administer and assess drug-like chemical compounds to the target cells since organisms probably did not develop molecular sensing elements to detect these types of carbon molecules. KW - SWCNT CNTs KW - pi-pi stacking KW - mean force potential KW - Gibbs free energy of binding KW - molecular docking KW - shape-based approach KW - Lamarckian genetic algorithms KW - gradient optimisation KW - drug delivery KW - multidrug resistance KW - P-glycoprotein KW - carbon nanoparticles KW - fullerenes KW - single-walled carbon nanotubes Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132089 VL - 6 IS - 4 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Bencurova, Elena A1 - Förster, Carola A1 - Dandekar, Thomas T1 - Modeling of shotgun sequencing of DNA plasmids using experimental and theoretical approaches JF - BMC Bioinformatics N2 - Background Processing and analysis of DNA sequences obtained from next-generation sequencing (NGS) face some difficulties in terms of the correct prediction of DNA sequencing outcomes without the implementation of bioinformatics approaches. However, algorithms based on NGS perform inefficiently due to the generation of long DNA fragments, the difficulty of assembling them and the complexity of the used genomes. On the other hand, the Sanger DNA sequencing method is still considered to be the most reliable; it is a reliable choice for virtual modeling to build all possible consensus sequences from smaller DNA fragments. Results In silico and in vitro experiments were conducted: (1) to implement and test our novel sequencing algorithm, using the standard cloning vectors of different length and (2) to validate experimentally virtual shotgun sequencing using the PCR technique with the number of cycles from 1 to 9 for each reaction. Conclusions We applied a novel algorithm based on Sanger methodology to correctly predict and emphasize the performance of DNA sequencing techniques as well as in de novo DNA sequencing and its further application in synthetic biology. We demonstrate the statistical significance of our results. KW - Shotgun method KW - Sanger sequencing KW - Virtual sequencing KW - Polymerase chain reaction KW - Gene expression vectors KW - Synthetic biology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229169 VL - 2020 ER - TY - JOUR A1 - Salvador, Ellaine A1 - Shityakov, Sergey A1 - Förster, Carola T1 - Glucocorticoids and endothelial cell barrier function JF - Cell and Tissue Research N2 - Glucocorticoids (GCs) are steroid hormones that have inflammatory and immunosuppressive effects on a wide variety of cells. They are used as therapy for inflammatory disease and as a common agent against edema. The blood brain barrier (BBB), comprising microvascular endothelial cells, serves as a permeability screen between the blood and the brain. As such, it maintains homeostasis of the central nervous system (CNS). In many CNS disorders, BBB integrity is compromised. GC treatment has been demonstrated to improve the tightness of the BBB. The responses and effects of GCs are mediated by the ubiquitous GC receptor (GR). Ligand-bound GR recognizes and binds to the GC response element located within the promoter region of target genes. Transactivation of certain target genes leads to improved barrier properties of endothelial cells. In this review, we deal with the role of GCs in endothelial cell barrier function. First, we describe the mechanisms of GC action at the molecular level. Next, we discuss the regulation of the BBB by GCs, with emphasis on genes targeted by GCs such as occludin, claudins and VE-cadherin. Finally, we present currently available GC therapeutic strategies and their limitations. KW - endothelial cells KW - glucocorticoids KW - glucocorticoid receptor KW - blood brain barrier Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132091 VL - 355 IS - 3 ER - TY - JOUR A1 - Rösing, Nils A1 - Salvador, Ellaine A1 - Güntzel, Paul A1 - Kempe, Christoph A1 - Burek, Malgorzata A1 - Holzgrabe, Ulrike A1 - Soukhoroukov, Vladimir A1 - Wunder, Christian A1 - Förster, Carola T1 - Neuroprotective Effects of Isosteviol Sodium in Murine Brain Capillary Cerebellar Endothelial Cells (cerebEND) After Hypoxia JF - Frontiers in Cellular Neuroscience N2 - Ischemic stroke is one of the leading causes of death worldwide. It damages neurons and other supporting cellular elements in the brain. However, the impairment is not only confined to the region of assault but the surrounding area as well. Besides, it also brings about damage to the blood-brain barrier (BBB) which in turn leads to microvascular failure and edema. Hence, this necessitates an on-going, continuous search for intervention strategies and effective treatment. Of late, the natural sweetener stevioside proved to exhibit neuroprotective effects and therapeutic benefits against cerebral ischemia-induced injury. Its injectable formulation, isosteviol sodium (STVNA) also demonstrated favorable results. Nonetheless, its effects on the BBB have not yet been investigated to date. As such, this present study was designed to assess the effects of STVNA in our in vitro stroke model of the BBB.The integrity and permeability of the BBB are governed and maintained by tight junction proteins (TJPs) such as claudin-5 and occludin. Our data show increased claudin-5 and occludin expression in oxygen and glucose (OGD)-deprived murine brain capillary cerebellar endothelial cells (cerebEND) after STVNa treatment. Likewise, the upregulation of the transmembrane protein integrin-αv was also observed. Finally, cell volume was reduced with the simultaneous administration of STVNA and OGD in cerebEND cells. In neuropathologies such as stroke, the failure of cell volume control is a major feature leading to loss of cells in the penumbra as well as adverse outcomes. Our initial findings, therefore, point to the neuroprotective effects of STVNA at the BBB in vitro, which warrant further investigation for a possible future clinical intervention. KW - isosteviol sodium KW - hypoxia KW - cerebEND cells KW - blood brain barrier KW - neuroprotection Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-215013 SN - 1662-5102 VL - 14 ER - TY - JOUR A1 - Neuhaus, Winfried A1 - Samwer, Fabian A1 - Kunzmann, Steffen A1 - Muellenbach, Ralph A1 - Wirth, Michael A1 - Speer, Christian P. A1 - Roewer, Norbert A1 - Förster, Carola T1 - Lung endothelial cells strengthen, but brain endothelial cells weaken barrier properties of a human alveolar epithelium cell culture model JF - Differentiation N2 - The blood-air barrier in the lung consists of the alveolar epithelium, the underlying capillary endothelium, their basement membranes and the interstitial space between the cell layers. Little is known about the interactions between the alveolar and the blood compartment. The aim of the present study was to gain first insights into the possible interplay between these two neighboured cell layers. We established an in vitro Transwell model of the alveolar epithelium based on human cell line H441 and investigated the influence of conditioned medium obtained from human lung endothelial cell line HPMEC-ST1.6R on the barrier properties of the H441 layers. As control for tissue specificity H441 layers were exposed to conditioned medium from human brain endothelial cell line hCMEC/D3. Addition of dexamethasone was necessary to obtain stable H441 cell layers. Moreover, dexamethasone increased expression of cell type I markers (caveolin-1, RAGE) and cell type II marker SP-B, whereas decreased the transepithelial electrical resistance (TEER) in a concentration dependent manner. Soluble factors obtained from the lung endothelial cell line increased the barrier significantly proven by TEER values and fluorescein permeability on the functional level and by the differential expression of tight junctional proteins on the molecular level. In contrast to this, soluble factors derived from brain endothelial cells weakened the barrier significantly. In conclusion, soluble factors from lung endothelial cells can strengthen the alveolar epithelium barrier in vitro, which suggests communication between endothelial and epithelial cells regulating the integrity of the blood-air barrier. KW - alveolar epithelium in vitro model, claudin-1, claudin-3, claudin-4, claudin-5 Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-90284 UR - http://www.sciencedirect.com/science/article/pii/S0301468112001144 VL - 84 IS - 4 ER - TY - JOUR A1 - Neuhaus, Winfried A1 - Gaiser, Fabian A1 - Mahringer, Anne A1 - Franz, Jonas A1 - Riethmüller, Christoph A1 - Förster, Carola T1 - The pivotal role of astrocytes in an in vitro stroke model of the blood-brain barrier JF - Frontiers in Cellular Neuroscience N2 - Stabilization of the blood-brain barrier during and after stroke can lead to less adverse outcome. For elucidation of underlying mechanisms and development of novel therapeutic strategies validated in vitro disease models of the blood-brain barrier could be very helpful. To mimic in vitro stroke conditions we have established a blood-brain barrier in vitro model based on mouse cell line cerebEND and applied oxygen/glucose deprivation (OGD). The role of astrocytes in this disease model was investigated by using cell line C6. Transwell studies pointed out that addition of astrocytes during OGD increased the barrier damage significantly in comparison to the endothelial monoculture shown by changes of transendothelial electrical resistance as well as fluorescein permeability data. Analysis on mRNA and protein levels by qPCR, western blotting and immunofluorescence microscopy of tight junction molecules claudin-3,-5,-12, occludin and ZO-1 revealed that their regulation and localisation is associated with the functional barrier breakdown. Furthermore, soluble factors of astrocytes, OGD and their combination were able to induce changes of functionality and expression of ABC-transporters Abcb1a (P-gp), Abcg2 (bcrp), and Abcc4 (mrp4). Moreover, the expression of proteases (matrixmetalloproteinases MMP-2, MMP-3, MMP-9, and t-PA) as well as of their endogenous inhibitors (TIMP-1, TIMP-3, PAI-1) was altered by astrocyte factors and OGD which resulted in significant changes of total MMP and t-PA activity. Morphological rearrangements induced by OGD and treatment with astrocyte factors were confirmed at a nanometer scale using atomic force microscopy. In conclusion, astrocytes play a major role in blood-brain barrier breakdown during OGD in vitro. KW - oxygen/glucose deprivation KW - ischemia KW - traumatic brain injury KW - cerebEND KW - C6 KW - stroke KW - in vitro KW - blood-brain barrier Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118297 SN - 1662-5102 VL - 8 ER - TY - JOUR A1 - Kaiser, Mathias A1 - Burek, Malgorzata A1 - Britz, Stefan A1 - Lankamp, Frauke A1 - Ketelhut, Steffi A1 - Kemper, Björn A1 - Förster, Carola A1 - Gorzelanny, Christian A1 - Goycoolea, Francisco M. T1 - The influence of capsaicin on the integrity of microvascular endothelial cell monolayers JF - International Journal of Molecular Sciences N2 - Microvascular endothelial cells are an essential part of many biological barriers, such as the blood–brain barrier (BBB) and the endothelium of the arteries and veins. A reversible opening strategy to increase the permeability of drugs across the BBB could lead to improved therapies due to enhanced drug bioavailability. Vanilloids, such as capsaicin, are known to reversibly open tight junctions of epithelial and endothelial cells. In this study, we used several in vitro assays with the murine endothelial capillary brain cells (line cEND) as a BBB model to characterize the interaction between capsaicin and endothelial tight junctions. KW - tight junctions KW - capsaicin KW - endothelial cells Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284865 SN - 1422-0067 VL - 20 IS - 1 ER -