The insulin receptor is expressed and functional in cultured blood-brain barrier endothelial cells but does not mediate insulin entry from blood to brain

Insulin and its receptor are known to be present and functional in the brain. Insulin cerebrospinal fluid concentrations have been shown to correlate with plasma levels of insulin in a nonlinear fashion, indicative of a saturable transport pathway from the blood to the brain interstitial fluid. The aim of the present study was to investigate whether insulin was transported across brain endothelial cells in vitro via an insulin receptor-dependent pathway. The study showed that the insulin receptor was expressed at both the mRNA and protein levels in bovine brain endothelial cells. Luminally applied radiolabeled insulin showed insulin receptor-mediated binding to the endothelial cells. This caused a dose-dependent increase in Akt-phosphorylation, which was inhibited by coapplication of an insulin receptor inhibitor, s961, demonstrating activation of insulin receptor signaling pathways. Transport of insulin across the blood-brain barrier in vitro was low and comparable to that of a similarly sized paracellular marker. Furthermore, insulin transport was not inhibited by coapplication of an excess of unlabeled insulin or an insulin receptor inhibitor. The insulin transport and uptake studies were repeated in mouse brain endothelial cells demonstrating similar results. Although it cannot be ruled out that culture-induced changes in the cell model could have impaired a potential insulin transport mechanism, these in vitro data indicate that peripheral insulin must reach the brain parenchyma through alternative pathways rather than crossing the blood-brain barrier via receptor mediated transcytosis.

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Anthropogenic Iron Oxide Nanoparticles Induce Damage to Brain Microvascular Endothelial Cells Forming the Blood-Brain Barrier

Advances in Alzheimer’s Disease - Alzheimer’s Disease and Air Pollution ◽

10.3233/aiad210010 ◽

2021 ◽

Author(s):

Lorena Gárate-Vélez ◽

Claudia Escudero-Lourdes ◽

Daniela Salado-Leza ◽

Armando González-Sánchez ◽

Ildemar Alvarado-Morales ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

Blood Brain ◽

Fe3o4 Nps ◽

Microvascular Endothelial ◽

The Brain

Background: Iron nanoparticles, mainly in magnetite phase (Fe3O4 NPs), are released to the environment in areas with high traffic density and braking frequency. Fe3O4 NPs were found in postmortem human brains and are assumed to get directly into the brain through the olfactory nerve. However, these pollution-derived NPs may also translocate from the lungs to the bloodstream and then, through the blood-brain barrier (BBB), into the brain inducing oxidative and inflammatory responses that contribute to neurodegeneration. Objective: To describe the interaction and toxicity of pollution-derived Fe3O4 NPs on primary rat brain microvascular endothelial cells (rBMECs), main constituents of in vitro BBB models. Methods: Synthetic bare Fe3O4 NPs that mimic the environmental ones (miFe3O4) were synthesized by co-precipitation and characterized using complementary techniques. The rBMECs were cultured in Transwell® plates. The NPs-cell interaction was evaluated through transmission electron microscopy and standard colorimetric in vitro assays. Results: The miFe3O4 NPs, with a mean diameter of 8.45 ± 0.14 nm, presented both magnetite and maghemite phases, and showed super-paramagnetic properties. Results suggest that miFe3O4 NPs are internalized by rBMECs through endocytosis and that they are able to cross the cells monolayer. The lowest miFe3O4 NPs concentration tested induced mid cytotoxicity in terms of 1) membrane integrity (LDH release) and 2) metabolic activity (MTS transformation). Conclusion: Pollution-derived Fe3O4 NPs may interact and cross the microvascular endothelial cells forming the BBB and cause biological damage.

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Modulation of Wnt/β-catenin signaling promotes blood-brain barrier phenotype in cultured brain endothelial cells

Scientific Reports ◽

10.1038/s41598-019-56075-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 9

Author(s):

Marlyn D. Laksitorini ◽

Vinith Yathindranath ◽

Wei Xiong ◽

Sabine Hombach-Klonisch ◽

Donald W. Miller

Keyword(s):

Endothelial Cells ◽

Wnt Signaling ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Brain Endothelial Cells ◽

Cancer Resistance ◽

Blood Brain ◽

Culture Model ◽

External Activation

AbstractWnt/β-catenin signaling is important for blood-brain barrier (BBB) development and is implicated in BBB breakdown under various pathophysiological conditions. In the present study, a comprehensive characterization of the relevant genes, transport and permeability processes influenced by both the autocrine and external activation of Wnt signaling in human brain endothelial cells was examined using hCMEC/D3 culture model. The hCMEC/D3 expressed a full complement of Wnt ligands and receptors. Preventing Wnt ligand release from hCMEC/D3 produced minimal changes in brain endothelial function, while inhibition of intrinsic/autocrine Wnt/β-catenin activity through blocking β-catenin binding to Wnt transcription factor caused more modest changes. In contrast, activation of Wnt signaling using exogenous Wnt ligand (Wnt3a) or LiCl (GSK3 inhibitor) improved the BBB phenotypes of the hCMEC/D3 culture model, resulting in reduced paracellular permeability, and increased P-glycoprotein (P-gp) and breast cancer resistance associated protein (BCRP) efflux transporter activity. Further, Wnt3a reduced plasmalemma vesicle associated protein (PLVAP) and vesicular transport activity in hCMEC/D3. Our data suggest that this in vitro model of the BBB has a more robust response to exogenous activation of Wnt/β-catenin signaling compared to autocrine activation, suggesting that BBB regulation may be more dependent on external activation of Wnt signaling within the brain microvasculature.

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Plasmodium falciparum erythrocyte membrane protein 1 variants induce cell swelling and disrupt the blood–brain barrier in cerebral malaria

Journal of Experimental Medicine ◽

10.1084/jem.20201266 ◽

2021 ◽

Vol 218 (3) ◽

Author(s):

Yvonne Adams ◽

Rebecca W. Olsen ◽

Anja Bengtsson ◽

Nanna Dalgaard ◽

Mykola Zdioruk ◽

...

Keyword(s):

Endothelial Cells ◽

Plasmodium Falciparum ◽

Cerebral Malaria ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Cell Swelling ◽

Dependent Manner ◽

Brain Endothelial Cells ◽

Blood Brain ◽

The Brain

Cerebral malaria (CM) is caused by the binding of Plasmodium falciparum–infected erythrocytes (IEs) to the brain microvasculature, leading to inflammation, vessel occlusion, and cerebral swelling. We have previously linked dual intercellular adhesion molecule-1 (ICAM-1)– and endothelial protein C receptor (EPCR)–binding P. falciparum parasites to these symptoms, but the mechanism driving the pathogenesis has not been identified. Here, we used a 3D spheroid model of the blood–brain barrier (BBB) to determine unexpected new features of IEs expressing the dual-receptor binding PfEMP1 parasite proteins. Analysis of multiple parasite lines shows that IEs are taken up by brain endothelial cells in an ICAM-1–dependent manner, resulting in breakdown of the BBB and swelling of the endothelial cells. Via ex vivo analysis of postmortem tissue samples from CM patients, we confirmed the presence of parasites within brain endothelial cells. Importantly, this discovery points to parasite ingress into the brain endothelium as a contributing factor to the pathology of human CM.

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The blood–brain barrier and its regulation by NF-κB

e-Neuroforum ◽

10.1515/s13295-016-0022-6 ◽

2016 ◽

Vol 22 (2) ◽

Author(s):

J. Wenzel ◽

M. Schwaninger

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Serum Proteins ◽

Hereditary Disease ◽

Brain Barrier ◽

Incontinentia Pigmenti ◽

Brain Endothelial Cells ◽

Blood Brain ◽

Endothelial Cell Death ◽

The Brain

AbstractThe brain is protected by a tight barrier between the blood and parenchyma. This so-called blood-brain barrier protects the brain from invading pathogens, infiltrating immune cells, and the extravasation of serum proteins. Beside pericytes and astrocytes mainly endothelial cells form this barrier.Inflammation leads to an increase in the permeability of the blood-brain barrier. NF-κB is activated during inflammation and is a key regulator of inflammatory processes. In brain endothelial cells NF-κB protects the blood-brain barrier. Loss of the NF-κB activating protein NEMO in brain endothelial cells leads to endothelial cell death, increased permeability, and epilepsy inmice as well as in humans with the hereditary disease incontinentia pigmenti. Therefore, inflammatory mediators are able to disturb but also to protect the blood-brain barrier.

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An Improved In Vitro Blood–Brain Barrier Model: Rat Brain Endothelial Cells Co-cultured with Astrocytes

Methods in Molecular Biology - Astrocytes ◽

10.1007/978-1-61779-452-0_28 ◽

2011 ◽

pp. 415-430 ◽

Cited By ~ 64

Author(s):

N. Joan Abbott ◽

Diana E. M. Dolman ◽

Svetlana Drndarski ◽

Sarah M. Fredriksson

Keyword(s):

Endothelial Cells ◽

Rat Brain ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Brain Endothelial Cells ◽

Blood Brain ◽

Blood Brain Barrier Model ◽

Rat Brain Endothelial Cells ◽

Barrier Model

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Primary Porcine Brain Endothelial Cells as In Vitro Model to Study Effects of Ultrasound and Microbubbles on Blood–Brain Barrier Function

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2016.2597004 ◽

2017 ◽

Vol 64 (1) ◽

pp. 281-290 ◽

Cited By ~ 12

Author(s):

S. Lelu ◽

M. Afadzi ◽

S. Berg ◽

A. K. O. Aslund ◽

S. H. Torp ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Barrier Function ◽

In Vitro Model ◽

Brain Barrier ◽

Brain Endothelial Cells ◽

Porcine Brain ◽

Blood Brain ◽

Vitro Model

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Capabilities of selenoneine to cross the in vitro blood-brain barrier model

Metallomics ◽

10.1093/mtomcs/mfaa007 ◽

2020 ◽

Author(s):

Evgenii Drobyshev ◽

Stefanie Raschke ◽

Ronald A Glabonjat ◽

Julia Bornhorst ◽

Franziska Ebert ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Culture Media ◽

Speciation Analysis ◽

Biological Properties ◽

Brain Barrier ◽

Blood Brain ◽

Icp Ms ◽

The Brain

Abstract The naturally occurring selenoneine (SeN), the selenium analogue of the sulfur-containing antioxidant ergothioneine, can be found in high abundance in several marine fish species. However, data on biological properties of SeN and its relevance for human health is still scarce. This study aims to investigate the transfer and presystemic metabolism of SeN in a well-established in vitro model of the blood-brain barrier (BBB). Therefore, the SeN and the reference Se species selenite and Se-methylselenocysteine (MeSeCys) were applied to primary porcine endothelial cells (PBCECs). Se content of culture media and cell lysates were measured via ICP-MS-MS. Speciation analysis was conducted by HPLC-ICP-MS. Barrier integrity was shown to be unaffected during transfer experiments. SeN demonstrated the lowest transfer rates and permeability coefficient (6.7 × 10−7 cm s−1) in comparison to selenite and MeSeCys. No side-directed accumulation was observed after both-sided application of SeN. However, concentration dependent transfer of SeN indicate possible presence of transporters on the both sides of the barrier. Speciation analysis demonstrated no methylation of SeN by the PBCECs. Several derivatives of SeN detected in the media of the BBB model were also found in cell free media containing SeN and hence not considered to be true metabolites of the PBCEC cells. Concluding, SeN is likely to have a slow transfer rate to the brain and not being metabolized by the brain endothelial cells. Since this study demonstrates, that SeN may reach the brain tissue, further studies are needed to investigate possible health-promoting effects of SeN in humans.

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