Glial Cell Line-Derived Neurotrophic Factor Induces Barrier Function of Endothelial Cells Forming the Blood–Brain Barrier

Tight junctions between endothelial cells of brain capillaries are the most important structural elements of the blood-brain barrier. Cultured brain endothelial cells are known to loose tight junction-dependent blood-brain barrier characteristics such as macromolecular impermeability and high electrical resistance. We have directly analyzed the structure and function of tight junctions in primary cultures of bovine brain endothelial cells using quantitative freeze-fracture electron microscopy, and ion and inulin permeability. The complexity of tight junctions, defined as the number of branch points per unit length of tight junctional strands, decreased 5 hours after culture but thereafter remained almost constant. In contrast, the association of tight junction particles with the cytoplasmic leaflet of the endothelial membrane bilayer (P-face) decreased continuously with a major drop between 16 hours and 24 hours. The complexity of tight junctions could be increased by elevation of intracellular cAMP levels while phorbol esters had the opposite effect. On the other hand, the P-face association of tight junction particles was enhanced by elevation of cAMP levels and by coculture of endothelial cells with astrocytes or exposure to astrocyte-conditioned medium. The latter effect on P-face association was induced by astrocytes but not fibroblasts. Elevation of cAMP levels together with astrocyte-conditioned medium synergistically increased transendothelial electrical resistance and decreased inulin permeability of primary cultures, thus confirming the effects on tight junction structure and barrier function. P-face association of tight junction particles in brain endothelial cells may therefore be a critical feature of blood-brain barrier function that can be specifically modulated by astrocytes and cAMP levels. Our results suggest an important functional role for the cytoplasmic anchorage of tight junction particles for brain endothelial barrier function in particular and probably paracellular permeability in general.

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Podocalyxin is required for maintaining blood–brain barrier function during acute inflammation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1814766116 ◽

2019 ◽

Vol 116 (10) ◽

pp. 4518-4527 ◽

Cited By ~ 8

Author(s):

Jessica Cait ◽

Michael R. Hughes ◽

Matthew R. Zeglinski ◽

Allen W. Chan ◽

Sabrina Osterhof ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Barrier Function ◽

Vascular Endothelial Cells ◽

Umbilical Vein ◽

Focal Adhesions ◽

Brain Barrier ◽

Cortical Actin ◽

Inflammatory Conditions ◽

Blood Brain

Podocalyxin (Podxl) is broadly expressed on the luminal face of most blood vessels in adult vertebrates, yet its function on these cells is poorly defined. In the present study, we identified specific functions for Podxl in maintaining endothelial barrier function. Using electrical cell substrate impedance sensing and live imaging, we found that, in the absence of Podxl, human umbilical vein endothelial cells fail to form an efficient barrier when plated on several extracellular matrix substrates. In addition, these monolayers lack adherens junctions and focal adhesions and display a disorganized cortical actin cytoskeleton. Thus, Podxl has a key role in promoting the appropriate endothelial morphogenesis required to form functional barriers. This conclusion is further supported by analyses of mutant mice in which we conditionally deleted a floxed allele ofPodxlin vascular endothelial cells (vECs) using Tie2Cre mice (PodxlΔTie2Cre). Although we did not detect substantially altered permeability in naïve mice, systemic priming with lipopolysaccharide (LPS) selectively disrupted the blood–brain barrier (BBB) inPodxlΔTie2Cremice. To study the potential consequence of this BBB breach, we used a selective agonist (TFLLR-NH2) of the protease-activated receptor-1 (PAR-1), a thrombin receptor expressed by vECs, neuronal cells, and glial cells. In response to systemic administration of TFLLR-NH2, LPS-primedPodxlΔTie2Cremice become completely immobilized for a 5-min period, coinciding with severely dampened neuroelectric activity. We conclude that Podxl expression by CNS tissue vECs is essential for BBB maintenance under inflammatory conditions.

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MRI-Guided Focused Ultrasound-Induced Blood Brain Barrier Disruption to Deliver Glial Cell Line Derived Neurotropic Factor Proteins into Brain to Treat Rat Depression

Journal of Biomedical Nanotechnology ◽

10.1166/jbn.2020.2914 ◽

2020 ◽

Vol 16 (5) ◽

pp. 626-639

Author(s):

Feng Wang ◽

Nana Li ◽

Xixi Wei ◽

Xiaojian Jia ◽

Huanhuan Liu ◽

...

Keyword(s):

Cell Line ◽

Glial Cell ◽

Blood Brain Barrier ◽

Focused Ultrasound ◽

Chronic Mild Stress ◽

Brain Barrier ◽

Mild Stress ◽

Blood Brain ◽

Mri Guided ◽

Neurotropic Factor

Glial cell line derived neurotropic factor (GDNF) plays a crucial role in the development and maintenance of glial cells, serotonergic and dopaminergic neurons. A positively therapeutic effect has been demonstrated on some animal neurodegenerative diseases. However, the inability to deliver the protein across blood brain barrier (BBB) into damaged brain region limits its clinical application. Here, we developed GDNF-loaded microbubbles (MBs) and achieved a local and precise delivery of GDNF into the brain through MRI-guided focused ultrasound-induced BBB disruption. To demonstrate the therapeutic effect, rat depression model was developed by chronic mild stress treatment. Typical depression behaviors were confirmed. MRI-guided focused ultrasound was used to irradiate the GDNF-loaded MBs. Obvious BBB opening was observed in the treated rat brains and a significant higher GDNF concentration was detected in the ultrasound-treated brain tissues. Behavioral tests demonstrated the increased GDNF could reverse the depressive-like behaviors induced by chronic mild stress, improve the expression of 5-HT 1B receptor and the protein p11, and increase the number of 5-HT or TPH2 immunoreactive neurons. In conclusion, our study provided an effective approach to deliver GDNF proteins into brain to treat rat depression through MRI-guided focused ultrasound-induced destruction of blood-brain barrier.

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Interactions between macrophages and brain microvascular endothelial cells: role in pathogenesis of HIV-1 infection and blood-brain barrier function

Journal of NeuroVirology ◽

10.3109/13550289909021294 ◽

1999 ◽

Vol 5 (6) ◽

pp. 659-669 ◽

Cited By ~ 58

Author(s):

Hans SLM Nottet

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Barrier Function ◽

Brain Barrier ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

Blood Brain ◽

Microvascular Endothelial ◽

Hiv 1

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Effects of neuromyelitis optica–IgG at the blood–brain barrier in vitro

Neurology Neuroimmunology & Neuroinflammation ◽

10.1212/nxi.0000000000000311 ◽

2016 ◽

Vol 4 (1) ◽

pp. e311 ◽

Cited By ~ 75

Author(s):

Yukio Takeshita ◽

Birgit Obermeier ◽

Anne C. Cotleur ◽

Simona F. Spampinato ◽

Fumitaka Shimizu ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Neuromyelitis Optica ◽

Barrier Function ◽

Brain Barrier ◽

Chemokine Production ◽

Leukocyte Transmigration ◽

Aqp4 Expression ◽

Blood Brain

Objective:To address the hypothesis that physiologic interactions between astrocytes and endothelial cells (EC) at the blood–brain barrier (BBB) are afflicted by pathogenic inflammatory signaling when astrocytes are exposed to aquaporin-4 (AQP4) antibodies present in the immunoglobulin G (IgG) fraction of serum from patients with neuromyelitis optica (NMO), referred to as NMO-IgG.Methods:We established static and flow-based in vitro BBB models incorporating co-cultures of conditionally immortalized human brain microvascular endothelial cells and human astrocyte cell lines with or without AQP4 expression.Results:In astrocyte–EC co-cultures, exposure of astrocytes to NMO-IgG decreased barrier function, induced CCL2 and CXCL8 expression by EC, and promoted leukocyte migration under flow, contingent on astrocyte expression of AQP4. NMO-IgG selectively induced interleukin (IL)-6 production by AQP4-positive astrocytes. When EC were exposed to IL-6, we observed decreased barrier function, increased CCL2 and CXCL8 expression, and enhanced leukocyte transmigration under flow. These effects were reversed after application of IL–6 neutralizing antibody.Conclusions:Our results indicate that NMO-IgG induces IL-6 production by AQP4-positive astrocytes and that IL-6 signaling to EC decreases barrier function, increases chemokine production, and enhances leukocyte transmigration under flow.

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