scholarly journals High-Resolution Insights Into the in vitro Developing Blood-Brain Barrier: Novel Morphological Features of Endothelial Nanotube Function

2021 ◽  
Vol 15 ◽  
Author(s):  
Shireen Mentor ◽  
David Fisher
Keyword(s):  
High Resolution ◽  
Blood Brain Barrier ◽  
Cell Communication ◽  
High Resolution Electron Microscopy ◽  
Brain Barrier ◽  
Transport Systems ◽  
Functional Roles ◽  
Blood Brain ◽  
First Time

High-resolution electron microscopy (HREM) imaging of the in vitro blood-brain barrier (BBB), is a promising modality for investigating the dynamic morphological interplay underpinning BBB development. The successful establishment of BBB integrity is grounded in the brain endothelial cells (BEC’s) ability to occlude its paracellular spaces of brain capillaries through the expression of the intercellular tight junction (TJ) proteins. The impermeability of these paracellular spaces are crucial in the regulation of transcellular transport systems to achieve homeostasis of the central nervous system. To-date research describing morphologically, the dynamics by which TJ interaction is orchestrated to successfully construct a specialized barrier remains undescribed. In this study, the application of HREM illuminates the novel, dynamic and highly restrictive BEC paracellular pathway which is founded based on lateral membrane alignment which is the functional imperative for the mechanical juxtapositioning of TJ zones that underpin molecular bonding and sealing of the paracellular space. For the first time, we report on the secretion of a basement membrane in vitro, which allow BECs to orientate themselves into distinct basolateral and apicolateral domains and establish a 3-dimensional BEC construct. We report for the first time, on the expression of nanovesicles bound to the plasma membrane surfaces of the BECs. These membrane-bound vesicles are reported to possess an array of DNA/RNA constituents and chemotaxic properties affecting the formation of nanotubes that span the paracellular space between BECs, facilitating BBB construction, alluding to a functional role in mediating cell-to-cell communication. This study suggests that novel, ultrathin nanotubular (NT) structures are involved in functional roles in bringing into alignment the paracellular space of BECs. Immortalized mouse BECs (b.End3, b.End5) and primary rat cardiac microvascular ECs were used to further validate the in vitro BBB model by profiling variances in peripheral EC monolayer development. These cardiac capillary ECs presented with an opposite topographical profile: large fenestra and intercellular spaces, devoid of morphological ultrastructures. This comparative study alludes to the role of NT facilitation in TJ-induced hemifusion of apicolateral BEC membranes, as a structural event forming the basis for establishing a polarized BBB.

scholarly journals An in-vitro BBB-on-a-chip open model of human blood-brain barrier enabling advanced optical imaging

2020 ◽  
Author(s):  
Mootaz Salman ◽  
Graham Marsh ◽  
Ilja Küsters ◽  
Matthieu Delincé ◽  
Giuseppe Di Caprio ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
High Resolution Electron Microscopy ◽  
Light Sheet ◽  
Brain Barrier ◽  
Open Model ◽  
Light Sheet Microscopy ◽  
Unidirectional Flow ◽  
Blood Brain ◽  
Resolution Electron

ABSTRACTWe describe here the design and implementation of an in-vitro BBB-on-a-chip open model system capable of reconstituting the microenvironment of the blood brain barrier. This system allows controlled unidirectional flow of nutrients and biologicals on the lumen of the artificial microvessel. This BBB-on-a-chip is suitable for high resolution electron microscopy and it is amenable for quantitative 3D live fluorescence imaging using spinning confocal disk or lattice light sheet microscopy (LLSM) to follow, for example the transcytosis across the BBB-like barrier of fluorescently-tagged biological, viruses or nanoparticles.

scholarly journals Biochemical‐ and Biophysical‐Induced Barriergenesis in the Blood–Brain Barrier: A Review of Barriergenic Factors for Use in In Vitro Models

2021 ◽  
Vol 1 (5) ◽  
pp. 2170051
Author(s):  
Christina L. Schofield ◽  
Aleixandre Rodrigo-Navarro ◽  
Matthew J. Dalby ◽  
Tom Van Agtmael ◽  
Manuel Salmeron-Sanchez
Keyword(s):  
Blood Brain Barrier ◽  
In Vitro Models ◽  
Brain Barrier ◽  
Blood Brain

scholarly journals Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 892
Author(s):  
Elisa L. J. Moya ◽  
Elodie Vandenhaute ◽  
Eleonora Rizzi ◽  
Marie-Christine Boucau ◽  
Johan Hachani ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Blood Brain Barrier ◽  
Early Stage ◽  
Molecular Transport ◽  
Brain Barrier ◽  
Blood Brain ◽  
Cns Drugs ◽  
The Impact ◽  
The Brain

Central nervous system (CNS) diseases are one of the top causes of death worldwide. As there is a difficulty of drug penetration into the brain due to the blood–brain barrier (BBB), many CNS drugs treatments fail in clinical trials. Hence, there is a need to develop effective CNS drugs following strategies for delivery to the brain by better selecting them as early as possible during the drug discovery process. The use of in vitro BBB models has proved useful to evaluate the impact of drugs/compounds toxicity, BBB permeation rates and molecular transport mechanisms within the brain cells in academic research and early-stage drug discovery. However, these studies that require biological material (animal brain or human cells) are time-consuming and involve costly amounts of materials and plastic wastes due to the format of the models. Hence, to adapt to the high yields needed in early-stage drug discoveries for compound screenings, a patented well-established human in vitro BBB model was miniaturized and automated into a 96-well format. This replicate met all the BBB model reliability criteria to get predictive results, allowing a significant reduction in biological materials, waste and a higher screening capacity for being extensively used during early-stage drug discovery studies.

scholarly journals Low nanogel stiffness favors nanogel transcytosis across an in vitro blood–brain barrier

2021 ◽  
Vol 34 ◽  
pp. 102377
Author(s):  
Laís Ribovski ◽  
Edwin de Jong ◽  
Olga Mergel ◽  
Guangyue Zu ◽  
Damla Keskin ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blood Brain

scholarly journals Bisphenol A Inhibits the Transporter Function of the Blood-Brain Barrier by Directly Interacting with the ABC Transporter Breast Cancer Resistance Protein (BCRP)

2021 ◽  
Vol 22 (11) ◽  
pp. 5534
Author(s):  
Elin Engdahl ◽  
Maarten van Schijndel ◽  
Dimitrios Voulgaris ◽  
Michela Di Criscio ◽  
Kerry Ramsbottom ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Bisphenol A ◽  
Blood Brain Barrier ◽  
Breast Cancer Resistance Protein ◽  
Brain Barrier ◽  
Production Volume ◽  
Cancer Resistance ◽  
Blood Brain ◽  
Resistance Protein

The breast cancer resistance protein (BCRP) is an important efflux transporter in the blood-brain barrier (BBB), protecting the brain from a wide range of substances. In this study, we investigated if BCRP function is affected by bisphenol A (BPA), a high production volume chemical used in common consumer products, as well as by bisphenol F (BPF) and bisphenol S (BPS), which are used to substitute BPA. We employed a transwell-based in vitro cell model of iPSC-derived brain microvascular endothelial cells, where BCRP function was assessed by measuring the intracellular accumulation of its substrate Hoechst 33342. Additionally, we used in silico modelling to predict if the bisphenols could directly interact with BCRP. Our results showed that BPA significantly inhibits the transport function of BCRP. Additionally, BPA was predicted to bind to the cavity that is targeted by known BCRP inhibitors. Taken together, our findings demonstrate that BPA inhibits BCRP function in vitro, probably by direct interaction with the transporter. This effect might contribute to BPA’s known impact on neurodevelopment.

scholarly journals Trojan Horse Transit Contributes to Blood-Brain Barrier Crossing of a Eukaryotic Pathogen

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Felipe H. Santiago-Tirado ◽  
Michael D. Onken ◽  
John A. Cooper ◽  
Robyn S. Klein ◽  
Tamara L. Doering
Keyword(s):  
Experimental Evidence ◽  
Cryptococcus Neoformans ◽  
Blood Brain Barrier ◽  
Fungal Pathogen ◽  
Trojan Horse ◽  
Brain Barrier ◽  
Barrier Crossing ◽  
Blood Brain ◽  
The Brain

ABSTRACT The blood-brain barrier (BBB) protects the central nervous system (CNS) by restricting the passage of molecules and microorganisms. Despite this barrier, however, the fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that is estimated to kill over 600,000 people annually. Cryptococcal infection begins in the lung, and experimental evidence suggests that host phagocytes play a role in subsequent dissemination, although this role remains ill defined. Additionally, the disparate experimental approaches that have been used to probe various potential routes of BBB transit make it impossible to assess their relative contributions, confounding any integrated understanding of cryptococcal brain entry. Here we used an in vitro model BBB to show that a “Trojan horse” mechanism contributes significantly to fungal barrier crossing and that host factors regulate this process independently of free fungal transit. We also, for the first time, directly imaged C. neoformans-containing phagocytes crossing the BBB, showing that they do so via transendothelial pores. Finally, we found that Trojan horse crossing enables CNS entry of fungal mutants that cannot otherwise traverse the BBB, and we demonstrate additional intercellular interactions that may contribute to brain entry. Our work elucidates the mechanism of cryptococcal brain invasion and offers approaches to study other neuropathogens. IMPORTANCE The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain. IMPORTANCE The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain.

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