Endothelioma Cells Research Articles

An exploratory study on the effect of kynurenine metabolites on sEnd-2 endothelioma cells.

Cancer is the second leading cause of mortality worldwide. The development of anticancer therapy plays a crucial role in mitigating tumour progression and metastasis. Epithelioid hemangioendothelioma is a very rare cancer, however, with a high systemic involvement. Kynurenine metabolites which includel-kynurenine, 3-hydroxykynurenine, 3-hydroxyanthranilic acid and quinolinic acid have been shown to inhibit T-cell proliferation resulting in a decrease in cell growth of natural killercells and T cells. Furthermore, metabolites such as l-kynurenine have been shown to inhibit proliferation of melanoma cells in vitro. Considering these metabolite properties, the present study aimed to explore the in vitro effects of l-kynurenine, quinolinic acid and kynurenic acid on endothelioma sEnd-2 cells and on endothelial (EA. hy926 cells) (control cell line). The in vitro effect at 24, 48, and 72 h exposure to a range of 1-4 mM of the respective kynurenine metabolites on the two cell lines in terms of cell morphology, cell cycle progression and induction of apoptosis was assessed. The half inhibitory concentration (IC50), as determined using nonlinear regression, for l-kynurenine, quinolinic acid and kynurenic acid was 9.17, 15.56, and 535.40 mM, respectively. Optical transmitted light differential interference contrast and hematoxylin and eosin staining revealed cells blocked in metaphase, formation of apoptotic bodies and compromised cell density in l-kynurenine-treated cells. A statistically significant increase in the number of cells present in the sub-G1 phase was observed in l-kynurenine-treated sample. To our knowledge, this was the first in vitro study conducted to investigate the mechanism of action of kynurenine metabolites on endothelioma sEnd-2 cells. It can be concluded that l-kynurenine exerts an antiproliferative effect on the endothelioma sEnd-2 cell line by decreasing cell growth and proliferation as well as a metaphase block. These hallmarks suggest cell death via apoptosis. Further research will be conducted on l-kynurenine to assess the effect on cell adhesion in vitro and in vivo as cell-cell adhesion has been shown to increase metastasis to distant organs therefore, the inhibition of adhesion may lead to a decrease in metastasis.

The In Vitro Effect of Kynurenine Metabolites on Cell morphology, Cell cycle progression and the Induction of Apoptosis in Tumour Endothelioma Cells

Background: Cancer is one of the leading causes of death worldwide. The development of anticancer therapies plays a crucial role in mitigating tumour progression and metastasis. Kynurenine metabolites which include L-kynurenine, 3-hydroxykynurenine, 3-hydroxyanthranilic acid and quinolinic acid have been shown to inhibit T-cell proliferation resulting in a decrease in cell growth of natural killer (NK) cells and T cells. Research showed that L-kynurenine inhibits proliferation of melanoma cells in vitro. Methods: The present study aimed to explore the in vitro influence of L-kynurenine, quinolinic acid and kynurenic acid on endothelioma sEnd-2 cells at concentration ranges of 1 mM – 4 mM for 24 h, 48 h and 72 h on cell morphology, cell cycle progression and induction of apoptosis. Results and Discussion: The half inhibitory concentration (IC50), as determined using GraphPad Prism, for L-kynurenine, quinolinic acid and kynurenic acid was 10.77 mM, 14.78 mM and 535.40 mM respectively. Optical transmitted light differential interference contrast and hematoxylin and eosin staining revealed the presence of cells blocked in metaphase, formation of apoptotic bodies and compromised cell density in L-kynurenine- and quinolinic acid- treated cells. A statistically significant increase in the number of cells present in the sub-G1 phase was observed in L-kynurenine-treated samples. Conclusion: It can be concluded that L-kynurenine exerts an antiproliferative effect on the sEnd-2 cell line by a decrease in cell growth and proliferation and metaphase block. These hallmarks suggest cell death via apoptosis. Further research will be conducted on L-kynurenine to assess the effect on cell adhesion in vitro and in vivo. This research was supported by the following grants: The Research Development Programme at the University of Pretoria awarded to Dr YN Hlophe; National Research Foundation awarded to Dr YN Hlophe (A1F4685 & N1F580); The University Capacity Development Programme (UCDP) awarded to Ms Tatchum (A1D783 & N1F120). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Oxidized Activated Charcoal Nanozymes: Synthesis, and Optimization for In Vitro and In Vivo Bioactivity for Traumatic Brain Injury.

Carbon-based superoxide dismutase (SOD) mimetic nanozymes have recently been employed as promising antioxidant nanotherapeutics due to their distinct properties. The structural features responsible for the efficacy of these nanomaterials as antioxidants are, however, poorly understood. Here, the process-structure-property-performance properties of coconut-derived oxidized activated charcoal (cOAC) nano-SOD mimetics are studied by analyzing how modifications to the nanomaterial's synthesis impact the size, as well as the elemental and electrochemical properties of the particles. These properties are then correlated to the in vitro antioxidant bioactivity of poly(ethylene glycol)-functionalized cOACs (PEG-cOAC). Chemical oxidative treatment methods that afford smaller, more homogeneous cOAC nanoparticles with higher levels of quinone functionalization show enhanced protection against oxidative damage in bEnd.3 murine endothelioma cells. In an in vivo rat model of mild traumatic brain injury (mTBI) and oxidative vascular injury, PEG-cOACs restore cerebral perfusion rapidly to the same extent as the former nanotube-derived PEG-hydrophilic carbon clusters (PEG-HCCs) with a single intravenous injection. These findings provide a deeper understanding of how carbon nanozyme syntheses can be tailored for improved antioxidant bioactivity, and set the stage for translation of medical applications.

Extracellular Alterations in pH and K+ Modify the Murine Brain Endothelial Cell Total and Phospho-Proteome.

Pathologies of the blood–brain barrier (BBB) have been linked to a multitude of central nervous system (CNS) disorders whose pathology is poorly understood. Cortical spreading depression (CSD) has long been postulated to be involved in the underlying mechanisms of these disease states, yet a complete understanding remains elusive. This study seeks to utilize an in vitro model of the blood–brain barrier (BBB) with brain endothelial cell (b.End3) murine endothelioma cells to investigate the role of CSD in BBB pathology by characterizing effects of the release of major pronociceptive substances into the extracellular space of the CNS. The application of trans-endothelial electrical resistance (TEER) screening, transcellular uptake, and immunoreactive methods were used in concert with global proteome and phospho-proteomic approaches to assess the effect of modeled CSD events on the modeled BBB in vitro. The findings demonstrate relocalization and functional alteration to proteins associated with the actin cytoskeleton and endothelial tight junctions. Additionally, unique pathologic mechanisms induced by individual substances released during CSD were found to have unique phosphorylation signatures in phospho-proteome analysis, identifying Zona Occludins 1 (ZO-1) as a possible pathologic “checkpoint” of the BBB. By utilizing these phosphorylation signatures, possible novel diagnostic methods may be developed for CSD and warrants further investigation.

Intranuclear Delivery of DNA Nanostructures via Cellular Mechanotransduction.

DNA nanostructures are attractive gene carriers for nanomedicine applications, yet their delivery to the nucleus remains inefficient. We present the application of extracellular mechanical stimuli to activate cellular mechanotransduction for boosting the intranuclear delivery of DNA nanostructures. Treating mammalian cells with polythymidine-rich spherical nucleic acids (poly(T) SNAs) under gentle compression by a single coverslip leads to up to ∼50% nuclear accumulation without severe endosomal entrapment, cytotoxicity, or long-term membrane damage; no chemical modification or transfection reagent is needed. Gentle compression activates Rho-ROCK mechanotransduction and causes nuclear translocation of YAP. Joint compression and treatment with poly(T) oligonucleotides upregulate genes linked to myosin, actin filament, and nuclear import. In turn, Rho-ROCK, myosin, and importin mediate the nuclear entry of poly(T) SNAs. Treatment of endothelioma cells with poly(T) SNAs bearing antisense oligonucleotides under compression inhibits an intranuclear oncogene. Our data should inspire the marriage of DNA nanotechnology and cellular biomechanics for intranuclear applications.

Differential Sensitivity of Two Endothelial Cell Lines to Hydrogen Peroxide Toxicity: Relevance for In Vitro Studies of the Blood-Brain Barrier.

Oxidative stress (OS) has been linked to blood–brain barrier (BBB) dysfunction which in turn has been implicated in the initiation and propagation of some neurological diseases. In this study, we profiled, for the first time, two endothelioma cell lines of mouse brain origin, commonly used as in vitro models of the blood–brain barrier, for their resistance against oxidative stress using viability measures and glutathione contents as markers. OS was induced by exposing cultured cells to varying concentrations of hydrogen peroxide and fluorescence microscopy/spectrometry was used to detect and estimate cellular glutathione contents. A colorimetric viability assay was used to determine changes in the viability of OS-exposed cells. Both the b.End5 and bEnd.3 cell lines investigated showed demonstrable content of glutathione with a statistically insignificant difference in glutathione quantity per unit cell, but with a statistically significant higher capacity for the b.End5 cell line for de novo glutathione synthesis. Furthermore, the b.End5 cells demonstrated greater oxidant buffering capacity to higher concentrations of hydrogen peroxide than the bEnd.3 cells. We concluded that mouse brain endothelial cells, derived from different types of cell lines, differ enormously in their antioxidant characteristics. We hereby recommend caution in making comparisons across BBB models utilizing distinctly different cell lines and require further prerequisites to ensure that in vitro BBB models involving these cell lines are reliable and reproducible.

Traditional Chinese Medicine (TCM) Astragalus Membranaceus and Curcuma Wenyujin Promote Vascular Normalization in Tumor-derived Endothelial Cells of Human Hepatocellular Carcinoma.

The aim of the present study was to investigate the vascular normalization effect of traditional Chinese medicine Astragalus membranaceus (AM) and Curcuma wenyujin (CW) on tumor-derived endothelial cells (TECs). TECs were isolated from the xenografted HCC cell line HepG2 expressing red fluorescent protein (RFP). The effect of AM and CW on TECs proliferation was measured using the CCK8 assay. The vascular normalization potential of AM and CW was assessed using a tube formation assay. Immunocytochemistry was performed to assess the effect of AM and CW on the expression of angiogenic maker CD34 and hypoxia-inducible factor HIF1a. The isolated TECs and endothelioma (EOMA) cells did not differ with regard to the expression levels of endothelial markers CD34, VEGFR-1, VEGFR-2, PDGFR-α and PDGFR-β. All AM, CW, AM+CW and Nintedanib (Nin) showed a dose-dependent increasing inhibition effect on either TECs or EOMA cells. AM, CW and AM+CW significantly reduced HIF1a expression, increased CD34 expression and enhanced endothelial network formation in TECs or EOMA cells compared to the control. AM and CW promoted vascular normalization in tumor-derived endothelial cells of HCC, through increased expression of CD34 and reduced expression of HIF1a.

Comparative in vitro transportation of pentamidine across the blood-brain barrier using polycaprolactone nanoparticles and phosphatidylcholine liposomes

Nanoparticles (NPs) have gained importance in addressing drug delivery challenges across biological barriers. Here, we reformulated pentamidine, a drug used to treat Human African Trypanosomiasis (HAT) in polymer based nanoparticles and liposomes and compared their capability to enhance pentamidine penetration across blood brain barrier (BBB). Size, polydispersity index, zeta potential, morphology, pentamidine loading and drug release profiles were determined by various methods. Cytotoxicity was tested against the immortalized mouse brain endothelioma cells over 96 h. Moreover, cells monolayer integrity and transportation ability were examined for 24 h. Pentamidine-loaded polycaprolactone (PCL) nanoparticles had a mean size of 267.58, PDI of 0.25 and zeta potential of –28.1 mV and pentamidine-loaded liposomes had a mean size of 119.61 nm, PDI of 0.25 and zeta potential 11.78. Pentamidine loading was 0.16 µg/mg (w/w) and 0.17 µg/mg (w/w) in PCL NPs and liposomes respectively. PCL nanoparticles and liposomes released 12.13% and 22.21% of pentamidine respectively after 24 h. Liposomes transported 87% of the dose, PCL NPs 66% of the dose and free pentamidine penetration was 63% of the dose. These results suggest that liposomes are comparatively promising nanocarriers for transportation of pentamidine across BBB.

Bioactive molecules isolated from olive pomace extract protect murine cortex neurons from NMDA‐mediated cell death

Here we demonstrate that olive pomace extracts contain bioactive molecules able to prevent primary neuron death induced by altered calcium homeostasis.We have observed previously that partially purified extracts counteracted calcium induced cell damages on human neuroblastoma (SK‐N‐BE) and mouse brain endothelioma (bEnd5) cell lines operating through the regulation of the cell dynamics that involve the calcium ions.It is well known that changes in [Ca2+]i are crucial events during signal transduction processes involved in several cellular physiological functions. Moreover, even a limited dysregulation in intracellular Ca2+ homeostasis is related to several acute and chronic diseases including neurodegenerations. In this context, we have now tested the effect of the bioactive molecules, detected in olive pomace, on primary cell cultures of murine cortex neurons, used as a cellular model. Accordingly, in order to induce a cytotoxic influx of Ca2+ through opening of the NMDA receptor, we treated neurons s with NMDA (N‐Methyl‐D‐Aspartic‐Acid) for 24 hour. When this cell treatment was carried out in the presence of preparations of the bioactive molecules, the effect of NMDA, evaluated as percentage of cell death, was significantly reduced. Moreover, following cell exposure to NMDA in the absence or the presence of the bioactive molecules, the [Ca2+]i was measured using different alternative techniques. The results obtained confirmed that these bioactive preparations act by molecular mechanisms that prevent the alteration of the intracellular calcium homeostasis mediated by NMDA. In conclusion, these bioactive molecules protect murine cortex neurons by reducing the toxic effects of [Ca2+]i, operated by the NMDA receptor. Further investigations are in progress to understand if the bioactive olive pomace derived molecules act directly on this receptor or on pathways activated downstream its opening. At present, the issue we give the highest priority is to identify the molecular nature of the relevant bioactive compounds. To solve this question we are carrying out mass spectrometry analyses on differently purified extracts.The ultimate aim is to achieve definitive conclusions about the potential practical applications for these natural molecules in their purified form. Indeed, providing comprehensive information about the structural and functional aspects of these molecules is crucial to propose new possible strategies for therapeutic interventions in neurodegenerations.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Growth hormone modulates in vitro endothelial cell migration and formation of capillary-like structures.

The generation of new blood vessels is a complex process mediated by a variety of growth factors, and the growth hormone (GH) has been shown to act as a proangiogenic factor. In fact, human GH deficiency or excess are associated with endothelial dysfunction. Moreover, mouse models have revealed the action of GH in both tissue repair and in the microvascular circulation of normal tissues. In this study, we investigated the in vitro effects of GH on endothelial cells. Using a murine endothelioma cell line (tEnd.1), we demonstrated that GH has a mitogenic effect. The hormone also affected the endothelial cellular morphology and augmented the deposition of the extracellular matrix molecules, laminin, and fibronectin, on tEnd.1 surface. GH could stimulate tEnd.1 cell fugetaxis, in transwell chambers migration assay, and increased the formation of capillary-like structures in Matrigel®-coated plates. Given the important role of angiogenesis during tissue injury, for example, at ischemic lesions, these findings shed light on therapeutic angiogenesis, particularly in pathologies where the cardiovascular system has been compromised.

Structural cartilage damage attracts circulating rheumatoid arthritis synovial fibroblasts into affected joints

BackgroundRheumatoid arthritis synovial fibroblasts (RASFs) are known to travel via the bloodstream from sites of cartilage destruction to new locations where they reinitiate the destructive processes at distant articular cartilage surfaces. In this study, we examined the role of interleukin (IL)-1-induced cartilage changes and their chemotactic effect on RASF transmigratory capacity.MethodsTo investigate synovial fibroblast (SF) transmigration through endothelial layers, we used a modified Boyden chamber with an endothelioma cell layer (bEnd.5) as a barrier and IL-1-treated murine cartilage explants as a chemotactic stimulus for SFs from human tumor necrosis factor–transgenic (hTNFtg) mice. We injected recombinant IL-1 or collagenase into knee joints of wild-type mice, followed by tail vein injection of fluorescence-labeled hTNFtg SFs. The distribution and intensity of transmigrating hTNFtg SFs were measured by fluorescence reflectance imaging with X-ray coregistration. Toluidine blue staining was performed to evaluate the amount of cartilage destruction.ResultsHistomorphometric analyses and in vivo imaging revealed a high degree of cartilage proteoglycan loss after intra-articular IL-1 and collagenase injection, accompanied by an enhanced in vivo extravasation of hTNFtg SFs into the respective knee joints, suggesting that structural cartilage damage contributes significantly to the attraction of hTNFtg SFs into these joints. In vitro results showed that degraded cartilage was directly responsible for the enhanced transmigratory capacity because stimulation with IL-1-treated cartilage, but not with IL-1 or cartilage alone, was required to increase hTNFtg SF migration.ConclusionsThe present data indicate that structural cartilage damage facilitates the migration of arthritic SF into affected joints. The prevention of early inflammatory cartilage damage may therefore help prevent the progression of rheumatoid arthritis and its spread to previously unaffected joints.

Novel 2,3-Dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones: Synthesis and Biological Evaluation.

Herein we describe the synthesis and evaluation of a series of novel 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones for in vitro cytotoxicity against three human cancer cell lines as well as for potential antimalarial activity against the chloroquine-sensitive strain 3D7 of Plasmodium falciparum. The title compounds were prepared via PdCl2-mediated endo-dig cyclization of 2-aryl-8-(arylethynyl)-6-bromo-2,3-dihydroquinazolin-4(1H)-ones. The latter were prepared, in turn, via initial Sonogashira cross-coupling of 2-amino-5-bromo-3-iodobenzamide with aryl acetylenes followed by boric acid-mediated cyclocondensation of the intermediate 2-amino-3-(arylethynyl)-5-bromobenzamides with benzaldehyde derivatives. The 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones 4a–k were evaluated for potential in vitro cytotoxicity against the breast (MCF-7), melanoma (B16) and endothelioma (sEnd.2) cell lines. All of the compounds except 4h and 4i were found to be inactive against the three cancer cell lines. Compound 4h substituted with a 4-methoxyphenyl and 4-fluorophenyl groups at the 3- and 5-positions was found to exhibit significant cytotoxicity against the three cancer cell lines. The presence of phenyl and 3-chlorophenyl groups at the 3- and 5-posiitons of the pyrroloquinazolinone 4i, on the other hand, resulted in significant cytotoxicity against vascular tumour endothelial cells (sEnd.2), but reduced activity against the melanoma (B16) and breast cancer (MCF-7) cells except at higher concentrations. The 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones 4a–l were found to be inactive against the chloroquine sensitive 3D7 strain of Plasmodium falciparum.

PF573,228 inhibits vascular tumor cell growth, migration as well as angiogenesis, induces apoptosis and abrogates PRAS40 and S6RP phosphorylation.

PF573,228 is a compound that targets focal adhesion kinase (FAK), a non-receptor protein kinase, which is over-expressed in various tumors. The aim of this study was to evaluate the effects of PF573,228 on the cells derived from mouse vascular tumors, namely, endothelioma cells. The treatment of endothelioma cells with PF573,228 reduced their growth with an IC50 of approximately 4.6 μmol L-1 and inhibited cell migration with an IC50 of about 0.01 μmol L-1. Microscopic studies revealed morphological attributes of apoptosis. These observations were confirmed by ELISA, which showed increased caspase-3 activity. PF573,228 also inhibited angiogenesis in a dose-dependent manner, with an IC50 of approximately 3.7 μmol L-1, and abrogated the phosphorylation of cell survival proteins, proline-rich Akt substrate (PRAS40) and S6 ribosomal protein (S6RP). Array data further revealed that PF573,228 induced caspase-3 activation, thus promoting apoptosis. Since all the processes inhibited by PF573,228 provide important support to tumor survival and progression, the drug may have a potential role in the treatment of vascular tumors.

Endothelial Expression of Endothelin Receptor A in the Systemic Capillary Leak Syndrome.

Idiopathic systemic capillary leak syndrome (SCLS) is a rare and potentially fatal vascular disorder characterized by reversible bouts of hypotension and edema resulting from fluid and solute escape into soft tissues. Although spikes in permeability-inducing factors have been linked to acute SCLS flares, whether or not they act on an inherently dysfunctional endothelium is unknown. To assess the contribution of endothelial-intrinsic mechanisms in SCLS, we derived blood-outgrowth endothelial cells (BOEC) from patients and healthy controls and examined gene expression patterns. Ednra, encoding Endothelin receptor A (ETA)—the target of Endothelin 1 (ET-1)—was significantly increased in SCLS BOEC compared to healthy controls. Although vasoconstriction mediated by ET-1 through ETA activation on vascular smooth muscle cells has been well characterized, the expression and function of ETA receptors in endothelial cells (ECs) has not been described. To determine the role of ETA and its ligand ET-1 in SCLS, if any, we examined ET-1 levels in SCLS sera and functional effects of endothelial ETA expression. ETA overexpression in EAhy926 endothelioma cells led to ET-1-induced hyper-permeability through canonical mechanisms. Serum ET-1 levels were elevated in acute SCLS sera compared to remission and healthy control sera, suggesting a possible role for ET-1 and ETA in SCLS pathogenesis. However, although ET-1 alone did not induce hyper-permeability of patient-derived BOEC, an SCLS-related mediator (CXCL10) increased Edrna quantities in BOEC, suggesting a link between SCLS and endothelial ETA expression. These results demonstrate that ET-1 triggers classical mechanisms of vascular barrier dysfunction in ECs through ETA. Further studies of the ET-1-ETA axis in SCLS and in more common plasma leakage syndromes including sepsis and filovirus infection would advance our understanding of vascular integrity mechanisms and potentially uncover new treatment strategies.

Repurposed biological scaffolds: kidney to pancreas

ABSTRACT. Advances in organ regeneration have been facilitated by gentle decellularization protocols that maintain distinct tissue compartments, and thereby allow seeding of blood vessels with endothelial lineages separate from populations of the parenchyma with tissue-specific cells. We hypothesized that a reconstituted vasculature could serve as a novel platform for perfusing cells derived from a different organ: thus discordance of origin between the vascular and functional cells, leading to a hybrid repurposed organ. The need for a highly vascular bed is highlighted by tissue engineering approaches that involve transplantation of just cells, as attempted for insulin production to treat human diabetes. Those pancreatic islet cells present unique challenges since large numbers are needed to allow the cell-to-cell signaling required for viability and proper function; however, increasing their number is limited by inadequate perfusion and hypoxia. As proof of principle of the repurposed organ methodology we harnessed the vasculature of a kidney scaffold while seeding the collecting system with insulin-producing cells. Pig kidneys were decellularized by sequential detergent, enzymatic and rinsing steps. Maintenance of distinct vascular and collecting system compartments was demonstrated by both fluorescent 10 micron polystyrene microspheres and cell distributions in tissue sections. Sterilized acellular scaffolds underwent seeding separately via the artery (fibroblasts or endothelioma cells) and retrograde (murine βTC-tet cells) up the ureter. After three-day bioreactor incubation, histology confirmed separation of cells in the vasculature from those in the collecting system. βTC-tet clusters survived in tubules, glomerular Bowman's space, demonstrated insulin immunolabeling, and thereby supported the feasibility of kidney-to-pancreas repurposing.

Altered expression of platelet factor 4 and basic fibroblast growth factor correlates with the inhibition of tumor growth in mice

Herein, we describe the effects of Taxol on endothelioma cell growth and migration in vitro and on vascular tumor growth in vivo. The effects of Taxol on endothelioma cell growth were determined using the crystal violet assay, while cell migration was measured using the xCELLIgence Real-Time Cell Analysis system. To study the effects of Taxol on tumor growth, mice were inoculated with endothelioma cells to induce vascular tumor development and were treated with the drug. At termination, tissue samples from Taxol-treated and control mice were stained with hematoxylin and eosin for histological examination, while blood samples were collected for hematological analysis, as well as for the analysis of the expression of angiogenic markers. In vitro, Taxol inhibited cell growth and migration. The drug also inhibited vascular tumor growth in mice, and this correlated with a recovery of mice from thrombocytopenia. Array analysis of blood samples from mice revealed that there was an increase in the expression of platelet factor 4 and a suppression of the proangiogenic molecule basic fibroblast growth factor in Taxol-treated animals. Our findings suggest that Taxol may have potential in the treatment of vascular tumors.

The heparan sulfate proteoglycan agrin contributes to barrier properties of mouse brain endothelial cells by stabilizing adherens junctions.

Barrier characteristics of brain endothelial cells forming the blood–brain barrier (BBB) are tightly regulated by cellular and acellular components of the neurovascular unit. During embryogenesis, the accumulation of the heparan sulfate proteoglycan agrin in the basement membranes ensheathing brain vessels correlates with BBB maturation. In contrast, loss of agrin deposition in the vasculature of brain tumors is accompanied by the loss of endothelial junctional proteins. We therefore wondered whether agrin had a direct effect on the barrier characteristics of brain endothelial cells. Agrin increased junctional localization of vascular endothelial (VE)-cadherin, β-catenin, and zonula occludens-1 (ZO-1) but not of claudin-5 and occludin in the brain endothelioma cell line bEnd5 without affecting the expression levels of these proteins. This was accompanied by an agrin-induced reduction of the paracellular permeability of bEnd5 monolayers. In vivo, the lack of agrin also led to reduced junctional localization of VE-cadherin in brain microvascular endothelial cells. Taken together, our data support the notion that agrin contributes to barrier characteristics of brain endothelium by stabilizing the adherens junction proteins VE-cadherin and β-catenin and the junctional protein ZO-1 to brain endothelial junctions.Electronic supplementary materialThe online version of this article (doi:10.1007/s00441-014-1969-7) contains supplementary material, which is available to authorized users.

Inflow versus outflow ischemia: differentiation and pharmacological characterization using cellular models (663.8)

Ischemia is a hallmark of stroke, myocardial infarction, and many other tissue injuries, and perhaps one of the best modeled human disease in laboratory animals. Nevertheless, it remains difficult to dissect the two main components of ischemia, the disruption of blood inflow versus blood outflow, in animal models. In this study, we attempt to differentiate these two components of tissue ischemia using cellular models. Inflow‐ischemia is induced by exchanging the nutrient‐enriched culture medium with a nutrient‐less extracellular solution, thereby mimicking the loss of nutritious blood supply. Outflow‐ischemia is induced by reducing the volume of the culture medium to allow more efficient accumulation of secretory products including metabolic wastes, thus resembling the disruption of blood outflow during tissue ischemia. Interestingly, while human embryonic kidney (HEK) cells are resistant to inflow‐ischemia, they degenerate abruptly upon outflow‐ischemia. In marked contrast, rat primary cortical neurons are highly susceptible to inflow‐ischemia, but strongly resistant to outflow‐ischemia. Lastly, the mouse endothelioma cells are resistant to either inflow‐ and outflow‐ischemia alone, and degenerated only when simultaneously subjected to both components of ischemia. As proof‐of‐concept, we demonstrated that outflow‐ischemia is transferrable between cell cultures by exchanging their culture media, and is fully reversible by re‐administration of fresh culture medium. Consistent with metabolic acidosis, cell death could be exacerbated and mitigated by decreasing and increasing pH of the culture medium, respectively. Moreover, the inhibitor amiloride prevented outflow‐ischemic death in a dose‐dependent manner. Taken together, the data reported here showed that different cell types are differentially susceptible to different components of ischemia, and further identified amiloride‐sensitive receptors as pharmacological targets against outflow‐ischemia.Grant Funding Source: Supported by the National Science Council of Taiwan

Inhibition of phosphoinositide 3-kinase is associated with reduced angiogenesis and an altered expression of angiogenic markers in endothelioma cells

The phosphoinositide 3-kinase (PI3k) signaling pathway is involved in the regulation of numerous cellular activities. The pathway has also been implicated in the development of various tumors. In the context of vascular tumors, the role of the PI3k signaling still needs to be established. In the present study, the effects of blocking PI3k activation on endothelioma cells derived from mice with vascular tumors were investigated using the crystal violet assay, real-time cell analysis, light microscopy, the aorta ring assay and antibody arrays. The suppression of PI3k led to the inhibition of cell growth, cell migration, as well as angiogenesis. The inhibition of these processes correlated with low Akt activity. Antibody array analysis revealed that there was a suppression of several proangiogenic molecules, including Eotaxin-1 and basic fibroblast growth factor (bFGF) in cultures treated with LY294,002, an inhibitor of PI3k. At the same time, LY294,002 increased the expression of platelet factor 4 (PF4) and the Fas ligand (FasL), molecules which have antiangiogenic properties. The results suggest that PI3k may play a role in the expression of some of the key regulatory molecules involved in angiogenesis, and perhaps in the growth of endotheliomas. As such, it is plausible that the PI3k/Akt pathway may be a target for therapeutic molecules designed for the treatment of endothelial tumors.

Controlling ferrofluid permeability across the blood–brain barrier model

In the present study, an in vitro blood–brain barrier model was developed using murine brain endothelioma cells (b.End3 cells). Confirmation of the blood–brain barrier model was completed by examining the permeability of FITC-Dextran at increasing exposure times up to 96 h in serum-free medium and comparing such values with values from the literature. After such confirmation, the permeability of five novel ferrofluid (FF) nanoparticle samples, GGB (ferrofluids synthesized using glycine, glutamic acid and BSA), GGC (glycine, glutamic acid and collagen), GGP (glycine, glutamic acid and PVA), BPC (BSA, PEG and collagen) and CPB (collagen, PVA and BSA), was determined using this blood–brain barrier model. All of the five FF samples were characterized by zeta potential to determine their charge as well as TEM and dynamic light scattering for determining their hydrodynamic diameter. Results showed that FF coated with collagen passed more easily through the blood–brain barrier than FF coated with glycine and glutamic acid based on an increase of 4.5% in permeability. Through such experiments, diverse magnetic nanomaterials (such as FF) were identified for: (1) MRI use since they were less permeable to penetrate the blood–brain barrier to avoid neural tissue toxicity (e.g. GGB) or (2) brain drug delivery since they were more permeable to the blood–brain barrier (e.g. CPB).