@article{NeuhausBurekDjuzenovaetal.2012, author = {Neuhaus, Winfried and Burek, Malgorzata and Djuzenova, Cholpon C and Thal, Serge C and Koepsell, Hermann and Roewer, Norbert and F{\"o}rster, Carola Y}, title = {Addition of NMDA-receptor antagonist MK801 during oxygen/glucose deprivation moderately attenuates the up-regulation of glucose uptake after subsequent reoxygenation in brain endothelial cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67241}, year = {2012}, abstract = {During stroke the blood-brain barrier (BBB) is damaged which can result in vasogenic brain edema and inflammation. The reduced blood supply leads to decreased delivery of oxygen and glucose to affected areas of the brain. Oxygen and glucose deprivation (OGD) can cause upregulation of glucose uptake of brain endothelial cells. In this letter, we investigated the influence of MK801, a non-competitive inhibitor of the NMDA-receptor, on the regulation of the glucose uptake and of the main glucose transporters glut1 and sglt1 in murine BBB cell line cerebEND during OGD. mRNA expression of glut1 was upregulated 68.7- fold after 6 h OGD, which was significantly reduced by 10 μM MK801 to 28.9-fold. Sglt1 mRNA expression decreased during OGD which was further reduced by MK801. Glucose uptake was significantly increased up to 907\% after 6 h OGD and was still higher (210\%) after the 20 h reoxygenation phase compared to normoxia. Ten micromolar MK801 during OGD was able to reduce upregulated glucose uptake after OGD and reoxygenation significantly. Presence of several NMDAR subunits was proven on the mRNA level in cerebEND cells. Furthermore, it was shown that NMDAR subunit NR1 was upregulated during OGD and that this was inhibitable by MK801. In conclusion, the addition of MK801 during the OGD phase reduced significantly the glucose uptake after the subsequent reoxygenation phase in brain endothelial cells.}, subject = {Blut-Hirn-Schranke}, language = {en} } @article{BurekSalvadorFoerster2012, author = {Burek, Malgorzata and Salvador, Ellaine and F{\"o}rster, Carola Y.}, title = {Generation of an Immortalized Murine Brain Microvascular Endothelial Cell Line as an In Vitro Blood Brain Barrier Model}, series = {Journal of Visualized Experiments}, volume = {66}, journal = {Journal of Visualized Experiments}, number = {e4022}, doi = {10.3791/4022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126702}, year = {2012}, abstract = {Epithelial and endothelial cells (EC) are building paracellular barriers which protect the tissue from the external and internal environment. The blood-brain barrier (BBB) consisting of EC, astrocyte end-feet, pericytes and the basal membrane is responsible for the protection and homeostasis of the brain parenchyma. In vitro BBB models are common tools to study the structure and function of the BBB at the cellular level. A considerable number of different in vitro BBB models have been established for research in different laboratories to date. Usually, the cells are obtained from bovine, porcine, rat or mouse brain tissue (discussed in detail in the review by Wilhelm et al. 1). Human tissue samples are available only in a restricted number of laboratories or companies 2,3. While primary cell preparations are time consuming and the EC cultures can differ from batch to batch, the establishment of immortalized EC lines is the focus of scientific interest. Here, we present a method for establishing an immortalized brain microvascular EC line from neonatal mouse brain. We describe the procedure step-by-step listing the reagents and solutions used. The method established by our lab allows the isolation of a homogenous immortalized endothelial cell line within four to five weeks. The brain microvascular endothelial cell lines termed cEND 4 (from cerebral cortex) and cerebEND 5 (from cerebellar cortex), were isolated according to this procedure in the F{\"o}rster laboratory and have been effectively used for explanation of different physiological and pathological processes at the BBB. Using cEND and cerebEND we have demonstrated that these cells respond to glucocorticoid- 4,6-9 and estrogen-treatment 10 as well as to pro-infammatory mediators, such as TNFalpha 5,8. Moreover, we have studied the pathology of multiple sclerosis 11 and hypoxia 12,13 on the EC-level. The cEND and cerebEND lines can be considered as a good tool for studying the structure and function of the BBB, cellular responses of ECs to different stimuli or interaction of the EC with lymphocytes or cancer cells.}, language = {en} } @article{SalvadorBurekFoerster2015, author = {Salvador, Ellaine and Burek, Malgorzata and F{\"o}rster, Carola Y.}, title = {Stretch and/or oxygen glucose deprivation (OGD) in an in vitro traumatic brain injury (TBI) model induces calcium alteration and inflammatory cascade}, series = {Frontiers in Cellular Neuroscience}, volume = {9}, journal = {Frontiers in Cellular Neuroscience}, number = {323}, doi = {10.3389/fncel.2015.00323}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148255}, year = {2015}, abstract = {The blood-brain barrier (BBB), made up of endothelial cells of capillaries in the brain, maintains the microenvironment of the central nervous system. During ischemia and traumatic brain injury (TBI), cellular disruption leading to mechanical insult results to the BBB being compromised. Oxygen glucose deprivation (OGD) is the most commonly used in vitro model for ischemia. On the other hand, stretch injury is currently being used to model TBI in vitro. In this paper, the two methods are used alone or in combination, to assess their effects on cerebrovascular endothelial cells cEND in the presence or absence of astrocytic factors. Applying severe stretch and/or OGD to cEND cells in our experiments resulted to cell swelling and distortion. Damage to the cells induced release of lactate dehydrogenase enzyme (LDH) and nitric oxide (NO) into the cell culture medium. In addition, mRNA expression of inflammatory markers interleukin (I L)-6, IL-1\(\alpha\) chemokine (C-C motif) ligand 2 (CCL2) and tumor necrosis factor (TNF)-\(\alpha\) also increased. These events could lead to the opening of calcium ion channels resulting to excitotoxicity. This could be demonstrated by increased calcium level in OGD-subjected cEND cells incubated with astrocyte-conditioned medium. Furthermore, reduction of cell membrane integrity decreased tight junction proteins claudin-5 and occludin expression. In addition, permeability of the endothelial cell monolayer increased. Also, since cell damage requires an increased uptake of glucose, expression of glucose transporter glut1 was found to increase at the mRNA level after OGD. Overall, the effects of OGD on cEND cells appear to be more prominent than that of stretch with regards to TJ proteins, NO, glutl expression, and calcium level. Astrocytes potentiate these effects on calcium level in cEND cells. Combining both methods to model TBI in vitro shows a promising improvement to currently available models.}, language = {en} } @article{KaiserBurekBritzetal.2018, author = {Kaiser, Mathias and Burek, Malgorzata and Britz, Stefan and Lankamp, Frauke and Ketelhut, Steffi and Kemper, Bj{\"o}rn and F{\"o}rster, Carola and Gorzelanny, Christian and Goycoolea, Francisco M.}, title = {The influence of capsaicin on the integrity of microvascular endothelial cell monolayers}, series = {International Journal of Molecular Sciences}, volume = {20}, journal = {International Journal of Molecular Sciences}, number = {1}, issn = {1422-0067}, doi = {10.3390/ijms20010122}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284865}, year = {2018}, abstract = {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.}, language = {en} } @article{RoesingSalvadorGuentzeletal.2020, author = {R{\"o}sing, Nils and Salvador, Ellaine and G{\"u}ntzel, Paul and Kempe, Christoph and Burek, Malgorzata and Holzgrabe, Ulrike and Soukhoroukov, Vladimir and Wunder, Christian and F{\"o}rster, Carola}, title = {Neuroprotective Effects of Isosteviol Sodium in Murine Brain Capillary Cerebellar Endothelial Cells (cerebEND) After Hypoxia}, series = {Frontiers in Cellular Neuroscience}, volume = {14}, journal = {Frontiers in Cellular Neuroscience}, issn = {1662-5102}, doi = {10.3389/fncel.2020.573950}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-215013}, year = {2020}, abstract = {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.}, language = {en} } @article{BurekBurmesterSalvadoretal.2020, author = {Burek, Malgorzata and Burmester, Sandra and Salvador, Ellaine and M{\"o}ller-Ehrlich, Kerstin and Schneider, Reinhard and Roewer, Norbert and Nagai, Michiaki and F{\"o}rster, Carola Y.}, title = {Kidney Ischemia/Reperfusion Injury Induces Changes in the Drug Transporter Expression at the Blood-Brain Barrier in vivo and in vitro}, series = {Frontiers in Physiology}, volume = {11}, journal = {Frontiers in Physiology}, issn = {1664-042X}, doi = {10.3389/fphys.2020.569881}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216413}, year = {2020}, abstract = {Ischemia/reperfusion injury is a major cause of acute kidney injury (AKI). AKI is characterized by a sudden decrease in kidney function, systemic inflammation, oxidative stress, and dysregulation of the sodium, potassium, and water channels. While AKI leads to uremic encephalopathy, epidemiological studies have shown that AKI is associated with a subsequent risk for developing stroke and dementia. To get more insights into kidney-brain crosstalk, we have created an in vitro co-culture model based on human kidney cells of the proximal tubule (HK-2) and brain microvascular endothelial cells (BMEC). The HK-2 cell line was grown to confluence on 6-well plates and exposed to oxygen/glucose deprivation (OGD) for 4 h. Control HK-2 cells were grown under normal conditions. The BMEC cell line cerebED was grown to confluence on transwells with 0.4 μm pores. The transwell filters seeded and grown to confluence with cereEND were inserted into the plates with HK-2 cells with or without OGD treatment. In addition, cerebEND were left untreated or treated with uremic toxins, indole-3-acetic acid (IAA) and indoxyl sulfate (IS). The protein and mRNA expression of selected BBB-typical influx transporters, efflux transporters, cellular receptors, and tight junction proteins was measured in BMECs. To validate this in vitro model of kidney-brain interaction, we isolated brain capillaries from mice exposed to bilateral renal ischemia (30 min)/reperfusion injury (24 h) and measured mRNA and protein expression as described above. Both in vitro and in vivo systems showed similar changes in the expression of drug transporters, cellular receptors, and tight junction proteins. Efflux pumps, in particular Abcb1b, Abcc1, and Abcg2, have shown increased expression in our model. Thus, our in vitro co-culture system can be used to study the cellular mechanism of kidney and brain crosstalk in renal ischemia/reperfusion injury.}, language = {en} } @article{GabbertDillingMeybohmetal.2020, author = {Gabbert, Lydia and Dilling, Christina and Meybohm, Patrick and Burek, Malgorzata}, title = {Deletion of Protocadherin Gamma C3 Induces Phenotypic and Functional Changes in Brain Microvascular Endothelial Cells In Vitro}, series = {Frontiers in Pharmacology}, volume = {11}, journal = {Frontiers in Pharmacology}, issn = {1663-9812}, doi = {10.3389/fphar.2020.590144}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219828}, year = {2020}, abstract = {Inflammation of the central nervous system (CNS) is associated with diseases such as multiple sclerosis, stroke and neurodegenerative diseases. Compromised integrity of the blood-brain barrier (BBB) and increased migration of immune cells into the CNS are the main characteristics of brain inflammation. Clustered protocadherins (Pcdhs) belong to a large family of cadherin-related molecules. Pcdhs are highly expressed in the CNS in neurons, astrocytes, pericytes and epithelial cells of the choroid plexus and, as we have recently demonstrated, in brain microvascular endothelial cells (BMECs). Knockout of a member of the Pcdh subfamily, PcdhgC3, resulted in significant changes in the barrier integrity of BMECs. Here we characterized the endothelial PcdhgC3 knockout (KO) cells using paracellular permeability measurements, proliferation assay, wound healing assay, inhibition of signaling pathways, oxygen/glucose deprivation (OGD) and a pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) treatment. PcdhgC3 KO showed an increased paracellular permeability, a faster proliferation rate, an altered expression of efflux pumps, transporters, cellular receptors, signaling and inflammatory molecules. Serum starvation led to significantly higher phosphorylation of extracellular signal-regulated kinases (Erk) in KO cells, while no changes in phosphorylated Akt kinase levels were found. PcdhgC3 KO cells migrated faster in the wound healing assay and this migration was significantly inhibited by respective inhibitors of the MAPK-, β-catenin/Wnt-, mTOR- signaling pathways (SL327, XAV939, or Torin 2). PcdhgC3 KO cells responded stronger to OGD and TNFα by significantly higher induction of interleukin 6 mRNA than wild type cells. These results suggest that PcdhgC3 is involved in the regulation of major signaling pathways and the inflammatory response of BMECs.}, language = {en} } @article{CurtazSchmittHerbertetal.2020, author = {Curtaz, Carolin J. and Schmitt, Constanze and Herbert, Saskia-Laureen and Feldheim, Jonas and Schlegel, Nicolas and Gosselet, Fabien and Hagemann, Carsten and Roewer, Norbert and Meybohm, Patrick and W{\"o}ckel, Achim and Burek, Malgorzata}, title = {Serum-derived factors of breast cancer patients with brain metastases alter permeability of a human blood-brain barrier model}, series = {Fluids and Barriers of the CNS}, volume = {17}, journal = {Fluids and Barriers of the CNS}, doi = {10.1186/s12987-020-00192-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229940}, year = {2020}, abstract = {Background The most threatening metastases in breast cancer are brain metastases, which correlate with a very poor overall survival, but also a limited quality of life. A key event for the metastatic progression of breast cancer into the brain is the migration of cancer cells across the blood-brain barrier (BBB). Methods We adapted and validated the CD34\(^+\) cells-derived human in vitro BBB model (brain-like endothelial cells, BLECs) to analyse the effects of patient serum on BBB properties. We collected serum samples from healthy donors, breast cancer patients with primary cancer, and breast cancer patients with, bone, visceral or cerebral metastases. We analysed cytokine levels in these sera utilizing immunoassays and correlated them with clinical data. We used paracellular permeability measurements, immunofluorescence staining, Western blot and mRNA analysis to examine the effects of patient sera on the properties of BBB in vitro. Results The BLECs cultured together with brain pericytes in transwells developed a tight monolayer with a correct localization of claudin-5 at the tight junctions (TJ). Several BBB marker proteins such as the TJ proteins claudin-5 and occludin, the glucose transporter GLUT-1 or the efflux pumps PG-P and BCRP were upregulated in these cultures. This was accompanied by a reduced paracellular permeability for fluorescein (400 Da). We then used this model for the treatment with the patient sera. Only the sera of breast cancer patients with cerebral metastases had significantly increased levels of the cytokines fractalkine (CX3CL1) and BCA-1 (CXCL13). The increased levels of fractalkine were associated with the estrogen/progesterone receptor status of the tumour. The treatment of BLECs with these sera selectively increased the expression of CXCL13 and TJ protein occludin. In addition, the permeability of fluorescein was increased after serum treatment. Conclusion We demonstrate that the CD34\(^+\) cell-derived human in vitro BBB model can be used as a tool to study the molecular mechanisms underlying cerebrovascular pathologies. We showed that serum from patients with cerebral metastases may affect the integrity of the BBB in vitro, associated with elevated concentrations of specific cytokines such as CX3CL1 and CXCL13.}, language = {en} } @article{SalvadorBurekLoehretal.2021, author = {Salvador, Ellaine and Burek, Malgorzata and L{\"o}hr, Mario and Nagai, Michiaki and Hagemann, Carsten and F{\"o}rster, Carola Y.}, title = {Senescence and associated blood-brain barrier alterations in vitro}, series = {Histochemistry and Cell Biology}, volume = {156}, journal = {Histochemistry and Cell Biology}, number = {3}, issn = {1432-119X}, doi = {10.1007/s00418-021-01992-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267435}, pages = {283-292}, year = {2021}, abstract = {Progressive deterioration of the central nervous system (CNS) is commonly associated with aging. An important component of the neurovasculature is the blood-brain barrier (BBB), majorly made up of endothelial cells joined together by intercellular junctions. The relationship between senescence and changes in the BBB has not yet been thoroughly explored. Moreover, the lack of in vitro models for the study of the mechanisms involved in those changes impede further and more in-depth investigations in the field. For this reason, we herein present an in vitro model of the senescent BBB and an initial attempt to identify senescence-associated alterations within.}, language = {en} } @article{TelesYanoVillarinhoetal.2021, author = {Teles, Ramon Handerson Gomes and Yano, Rafael Sussumu and Villarinho, Nicolas Jones and Yamagata, Ana Sayuri and Jaeger, Ruy Gastaldoni and Meybohm, Patrick and Burek, Malgorzata and Freitas, Vanessa Morais}, title = {Advances in breast cancer management and extracellular vesicle research, a bibliometric analysis}, series = {Current Oncology}, volume = {28}, journal = {Current Oncology}, number = {6}, issn = {1718-7729}, doi = {10.3390/curroncol28060382}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284321}, pages = {4504 -- 4520}, year = {2021}, abstract = {Extracellular vesicles transport variable content and have crucial functions in cell-cell communication. The role of extracellular vesicles in cancer is a current hot topic, and no bibliometric study has ever analyzed research production regarding their role in breast cancer and indicated the trends in the field. In this way, we aimed to investigate the trends in breast cancer management involved with extracellular vesicle research. Articles were retrieved from Scopus, including all the documents published concerning breast cancer and extracellular vesicles. We analyzed authors, journals, citations, affiliations, and keywords, besides other bibliometric analyses, using R Studio version 3.6.2. and VOSviewer version 1.6.0. A total of 1151 articles were retrieved, and as the main result, our analysis revealed trending topics on biomarkers of liquid biopsy, drug delivery, chemotherapy, autophagy, and microRNA. Additionally, research related to extracellular vesicles in breast cancer has been focused on diagnosis, treatment, and mechanisms of action of breast tumor-derived vesicles. Future studies are expected to explore the role of extracellular vesicles on autophagy and microRNA, besides investigating the application of extracellular vesicles from liquid biopsies for biomarkers and drug delivery, enabling the development and validation of therapeutic strategies for specific cancers.}, language = {en} }