scholarly journals Blood-Brain Barrier Dysfunction Amplifies the Development of Neuroinflammation: Understanding of Cellular Events in Brain Microvascular Endothelial Cells for Prevention and Treatment of BBB Dysfunction

2021 ◽  
Vol 15 ◽  
Author(s):  
Fuyuko Takata ◽  
Shinsuke Nakagawa ◽  
Junichi Matsumoto ◽  
Shinya Dohgu
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathways ◽  
Blood Brain Barrier ◽  
Glial Cells ◽  
Inflammatory Mediators ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Perivascular Cells ◽  
Cellular Components ◽  
The Brain

Neuroinflammation is involved in the onset or progression of various neurodegenerative diseases. Initiation of neuroinflammation is triggered by endogenous substances (damage-associated molecular patterns) and/or exogenous pathogens. Activation of glial cells (microglia and astrocytes) is widely recognized as a hallmark of neuroinflammation and triggers the release of proinflammatory cytokines, leading to neurotoxicity and neuronal dysfunction. Another feature associated with neuroinflammatory diseases is impairment of the blood-brain barrier (BBB). The BBB, which is composed of brain endothelial cells connected by tight junctions, maintains brain homeostasis and protects neurons. Impairment of this barrier allows trafficking of immune cells or plasma proteins into the brain parenchyma and subsequent inflammatory processes in the brain. Besides neurons, activated glial cells also affect BBB integrity. Therefore, BBB dysfunction can amplify neuroinflammation and act as a key process in the development of neuroinflammation. BBB integrity is determined by the integration of multiple signaling pathways within brain endothelial cells through intercellular communication between brain endothelial cells and brain perivascular cells (pericytes, astrocytes, microglia, and oligodendrocytes). For prevention of BBB disruption, both cellular components, such as signaling molecules in brain endothelial cells, and non-cellular components, such as inflammatory mediators released by perivascular cells, should be considered. Thus, understanding of intracellular signaling pathways that disrupt the BBB can provide novel treatments for neurological diseases associated with neuroinflammation. In this review, we discuss current knowledge regarding the underlying mechanisms involved in BBB impairment by inflammatory mediators released by perivascular cells.

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

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.

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

e-Neuroforum ◽  
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.

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

2018 ◽  
Vol 315 (4) ◽  
pp. E531-E542 ◽  
Author(s):  
Maria Hersom ◽  
Hans C. Helms ◽  
Christoffer Schmalz ◽  
Thomas Å. Pedersen ◽  
Stephen T. Buckley ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Insulin Receptor ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Insulin Transport ◽  
Blood Brain ◽  
The Brain ◽  
Receptor Inhibitor

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.

scholarly journals Single-Cell Analysis of Blood-Brain Barrier Response to Pericyte Loss

2020 ◽  
Author(s):  
Maarja Andaloussi Mäe ◽  
Liqun He ◽  
Sofia Nordling ◽  
Elisa Vazquez-Liebanas ◽  
Khayrun Nahar ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Single Cell ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Specific Gene ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Brain Pericytes ◽  
Endothelial Response ◽  
The Brain

Rationale: Pericytes are capillary mural cells playing a role in stabilizing newly formed blood vessels during development and tissue repair. Loss of pericytes has been described in several brain disorders, and genetically induced pericyte deficiency in the brain leads to increased macromolecular leakage across the blood-brain barrier (BBB). However, the molecular details of the endothelial response to pericyte deficiency remain elusive. Objective: To map the transcriptional changes in brain endothelial cells resulting from lack of pericyte contact at single-cell level, and to correlate them with regional heterogeneities in BBB function and vascular phenotype. Methods and Results: We reveal transcriptional, morphological and functional consequences of pericyte absence for brain endothelial cells using a combination of methodologies, including single-cell RNA sequencing, tracer analyses and immunofluorescent detection of protein expression in pericyte-deficient adult Pdgfbret/ret mice. We find that endothelial cells without pericyte contact retain a general BBB-specific gene expression profile, however, they acquire a venous-shifted molecular pattern and become transformed regarding the expression of numerous growth factors and regulatory proteins. Adult Pdgfbret/ret brains display ongoing angiogenic sprouting without concomitant cell proliferation providing unique insights into the endothelial tip cell transcriptome. We also reveal heterogeneous modes of pericyte-deficient BBB impairment, where hotspot leakage sites display arteriolar-shifted identity and pinpoint putative BBB regulators. By testing the causal involvement of some of these using reverse genetics, we uncover a reinforcing role for angiopoietin 2 at the BBB. Conclusions: By elucidating the complexity of endothelial response to pericyte deficiency at cellular resolution, our study provides insight into the importance of brain pericytes for endothelial arterio-venous zonation, angiogenic quiescence and a limited set of BBB functions. The BBB-reinforcing role of ANGPT2 is paradoxical given its wider role as TIE2 receptor antagonist and may suggest a unique and context-dependent function of ANGPT2 in the brain.

scholarly journals Enterovirus A71 capsid protein VP1 increases blood–brain barrier permeability and virus receptor vimentin on the brain endothelial cells

2019 ◽  
Vol 26 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Wenjing Wang ◽  
Jiandong Sun ◽  
Nan Wang ◽  
Zhixiao Sun ◽  
Qiyun Ma ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Capsid Protein ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Virus Receptor ◽  
Blood Brain ◽  
Enterovirus A71 ◽  
Capsid Protein Vp1 ◽  
The Brain

Abstract Enterovirus A71 (EV-A71) is the major cause of severe hand-foot-and-mouth diseases (HFMD), especially encephalitis and other nervous system diseases. EV-A71 capsid protein VP1 mediates virus attachment and is the important virulence factor in the EV-A71pathogenesis. In this study, we explored the roles of VP1 in the permeability of blood–brain barrier (BBB). Sera albumin, Evans blue, and dextran leaked into brain parenchyma of the 1-week-old C57BL/6J mice intracranially injected with VP1 recombinant protein. VP1 also increased the permeability of the brain endothelial cells monolayer, an in vitro BBB model. Tight junction protein claudin-5 was reduced in the brain tissues or brain endothelial cells treated with VP1. In contrast, VP1 increased the expression of virus receptor vimentin, which could be blocked with VP1 neutralization antibody. Vimentin expression in the VP1-treated brain endothelial cells was regulated by TGF-β/Smad-3 and NF-κB signal pathways. Moreover, vimentin over-expression was accompanied with compromised BBB. From these studies, we conclude that EV-A71 virus capsid protein VP1 disrupted BBB and increased virus receptor vimentin, which both may contribute to the virus entrance into brain and EV-A71 CNS infection.

scholarly journals Targeting nanoparticles to the brain by exploiting the blood–brain barrier impermeability to selectively label the brain endothelium

2020 ◽  
Vol 117 (32) ◽  
pp. 19141-19150 ◽  
Author(s):  
Daniel Gonzalez-Carter ◽  
Xueying Liu ◽  
Theofilus A. Tockary ◽  
Anjaneyulu Dirisala ◽  
Kazuko Toh ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Brain Targeting ◽  
Brain Endothelial Cells ◽  
Brain Endothelium ◽  
Target Proteins ◽  
Blood Brain ◽  
Brain Microvasculature ◽  
The Brain

Current strategies to direct therapy-loaded nanoparticles to the brain rely on functionalizing nanoparticles with ligands which bind target proteins associated with the blood–brain barrier (BBB). However, such strategies have significant brain-specificity limitations, as target proteins are not exclusively expressed at the brain microvasculature. Therefore, novel strategies which exploit alternative characteristics of the BBB are required to overcome nonspecific nanoparticle targeting to the periphery, thereby increasing drug efficacy and reducing detrimental peripheral side effects. Here, we present a simple, yet counterintuitive, brain-targeting strategy which exploits the higher impermeability of the BBB to selectively label the brain endothelium. This is achieved by harnessing the lower endocytic rate of brain endothelial cells (a key feature of the high BBB impermeability) to promote selective retention of free, unconjugated protein-binding ligands on the surface of brain endothelial cells compared to peripheral endothelial cells. Nanoparticles capable of efficiently binding to the displayed ligands (i.e., labeled endothelium) are consequently targeted specifically to the brain microvasculature with minimal “off-target” accumulation in peripheral organs. This approach therefore revolutionizes brain-targeting strategies by implementing a two-step targeting method which exploits the physiology of the BBB to generate the required brain specificity for nanoparticle delivery, paving the way to overcome targeting limitations and achieve clinical translation of neurological therapies. In addition, this work demonstrates that protein targets for brain delivery may be identified based not on differential tissue expression, but on differential endocytic rates between the brain and periphery.

scholarly journals Effects of cadmium on the glial architecture in lizard brain

2017 ◽  
Author(s):  
Rossana Favorito ◽  
Antonio Monaco ◽  
Maria C. Grimaldi ◽  
Ida Ferrandino
Keyword(s):  
Blood Brain Barrier ◽  
Glial Cells ◽  
Toxic Metal ◽  
Chemical Exposure ◽  
Brain Barrier ◽  
Cresyl Violet ◽  
Cytotoxic Action ◽  
Morphological Alterations ◽  
Blood Brain ◽  
The Brain

The glial cells are positioned to be the first cells of the brain parenchyma to face molecules crossing the blood-brain barrier with a relevant neuroprotective role from cytotoxic action of heavy metals on the nervous system. Cadmium is a highly toxic metal and its levels in the environment are increasing due to industrial activities. This element can pass the blood-brain barrier and have neurotoxic activity. For this reason we have studied the effects of cadmium on the glial architecture in the lizard Podarcis siculus, a significant bioindicator of chemical exposure due to its persistence in a variety of habitats. The study was performed on two groups of lizards. The first group of P. siculus was exposed to an acute treatment by a single i.p. injection (2 mg/kg-BW) of CdCl2 and sacrificed after 2, 7 and 16 days. The second one was used as control. The histology of the brain was studied by Hematoxylin/Eosin and Cresyl/Violet stains while the glial structures were analyzed by immunodetection of the glial fibrillary acidic protein (GFAP), the most widely accepted marker for astroglial cells. Evident morphological alterations of the brain were observed at 7 and 16 days from the injection, when we revealed also a decrease of the GFAP-immunopositive structures in particular in the rhombencephalic ventricle, telencephalon and optic tectum. These results show that in the lizards an acute exposure to cadmium provokes morphological cellular alterations in the brain but also a decrement of the expression of GFAP marker with possible consequent damage of glial cells functions.

Neural precursor cell influences on blood–brain barrier characteristics in rat brain endothelial cells

2007 ◽  
Vol 1159 ◽  
pp. 67-76 ◽  
Author(s):  
Joseph C. Lim ◽  
Adam J. Wolpaw ◽  
Maeve A. Caldwell ◽  
Stephen B. Hladky ◽  
Margery A. Barrand
Keyword(s):  
Endothelial Cells ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
Precursor Cell ◽  
Brain Barrier ◽  
Neural Precursor ◽  
Brain Endothelial Cells ◽  
Neural Precursor Cell ◽  
Blood Brain ◽  
Rat Brain Endothelial Cells

scholarly journals Characterization of a Primate Blood-Brain Barrier Co-Culture Model Prepared from Primary Brain Endothelial Cells, Pericytes and Astrocytes

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1484
Author(s):  
Daisuke Watanabe ◽  
Shinsuke Nakagawa ◽  
Yoichi Morofuji ◽  
Andrea E. Tóth ◽  
Monika Vastag ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Transport Systems ◽  
Brain Endothelial Cells ◽  
Monkey Brain ◽  
Blood Brain ◽  
Culture Model ◽  
Culture Models ◽  
Human Primate

Culture models of the blood-brain barrier (BBB) are important research tools. Their role in the preclinical phase of drug development to estimate the permeability for potential neuropharmaceuticals is especially relevant. Since species differences in BBB transport systems exist, primate models are considered as predictive for drug transport to brain in humans. Based on our previous expertise we have developed and characterized a non-human primate co-culture BBB model using primary cultures of monkey brain endothelial cells, rat brain pericytes, and rat astrocytes. Monkey brain endothelial cells in the presence of both pericytes and astrocytes (EPA model) expressed enhanced barrier properties and increased levels of tight junction proteins occludin, claudin-5, and ZO-1. Co-culture conditions also elevated the expression of key BBB influx and efflux transporters, including glucose transporter-1, MFSD2A, ABCB1, and ABCG2. The correlation between the endothelial permeability coefficients of 10 well known drugs was higher (R2 = 0.8788) when the monkey and rat BBB culture models were compared than when the monkey culture model was compared to mouse in vivo data (R2 = 0.6619), hinting at transporter differences. The applicability of the new non-human primate model in drug discovery has been proven in several studies.

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