Selective Activation of Cannabinoid Receptor 2 in Leukocytes Suppresses Their Engagement of the Brain Endothelium and Protects the Blood-Brain Barrier

The non-human primate (NHP)-brain endothelium constitutes an essential alternative to human in the prediction of molecule trafficking across the blood–brain barrier (BBB). This study presents a comparison between the NHP transcriptome of freshly isolated brain microcapillaries and in vitro-selected brain endothelial cells (BECs), focusing on important BBB features, namely tight junctions, receptors mediating transcytosis (RMT), ABC and SLC transporters, given its relevance as an alternative model for the molecule trafficking prediction across the BBB and identification of new brain-specific transport mechanisms. In vitro BECs conserved most of the BBB key elements for barrier integrity and control of molecular trafficking. The function of RMT via the transferrin receptor (TFRC) was characterized in this NHP-BBB model, where both human transferrin and anti-hTFRC antibody showed increased apical-to-basolateral passage in comparison to control molecules. In parallel, eventual BBB-related regional differences were Investig.igated in seven-day in vitro-selected BECs from five brain structures: brainstem, cerebellum, cortex, hippocampus, and striatum. Our analysis retrieved few differences in the brain endothelium across brain regions, suggesting a rather homogeneous BBB function across the brain parenchyma. The presently established NHP-derived BBB model closely mimics the physiological BBB, thus representing a ready-to-use tool for assessment of the penetration of biotherapeutics into the human CNS.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2002016117 ◽

2020 ◽

Vol 117 (32) ◽

pp. 19141-19150 ◽

Cited By ~ 5

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.

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miR-98 reduces endothelial dysfunction by protecting blood–brain barrier (BBB) and improves neurological outcomes in mouse ischemia/reperfusion stroke model

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x19882264 ◽

2019 ◽

Vol 40 (10) ◽

pp. 1953-1965 ◽

Cited By ~ 10

Author(s):

David L Bernstein ◽

Viviana Zuluaga-Ramirez ◽

Sachin Gajghate ◽

Nancy L Reichenbach ◽

Boris Polyak ◽

...

Keyword(s):

Blood Brain Barrier ◽

Ischemia Reperfusion ◽

Glucose Deprivation ◽

Brain Barrier ◽

Inflammatory Factors ◽

Brain Endothelium ◽

Blood Brain ◽

The Brain

Most neurological diseases, including stroke, lead to some degree of blood–brain barrier (BBB) dysfunction. A significant portion of BBB injury is caused by inflammation, due to pro-inflammatory factors produced in the brain, and by leukocyte engagement of the brain endothelium. Recently, microRNAs (miRNAs) have appeared as major regulators of inflammation-induced changes to gene expression in the microvascular endothelial cells (BMVEC) that comprise the BBB. However, miRNAs’ role during cerebral ischemia/reperfusion is still underexplored. Endothelial levels of miR-98 were significantly altered following ischemia/reperfusion insults, both in vivo and in vitro, transient middle cerebral artery occlusion (tMCAO), and oxygen–glucose deprivation (OGD), respectively. Overexpression of miR-98 reduced the mouse’s infarct size after tMCAO. Further, miR-98 lessened infiltration of proinflammatory Ly6CHI leukocytes into the brain following stroke and diminished the prevalence of M1 (activated) microglia within the impacted area. miR-98 attenuated BBB permeability, as demonstrated by changes to fluorescently-labeled dextran penetration in vivo and improved transendothelial electrical resistance (TEER) in vitro. Treatment with miR-98 improved significantly the locomotor impairment. Our study provides identification and functional assessment of miRNAs in brain endothelium and lays the groundwork for improving therapeutic approaches for patients suffering from ischemic attacks.

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Faculty Opinions recommendation of Activation of cannabinoid receptor 2 attenuates leukocyte-endothelial cell interactions and blood-brain barrier dysfunction under inflammatory conditions.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717961059.793463863 ◽

2012 ◽

Author(s):

Anirban Basu

Keyword(s):

Endothelial Cell ◽

Blood Brain Barrier ◽

Cannabinoid Receptor ◽

Cell Interactions ◽

Brain Barrier ◽

Barrier Dysfunction ◽

Cannabinoid Receptor 2 ◽

Inflammatory Conditions ◽

Blood Brain

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Differential ubiquitination as an effective strategy employed by Blood-Brain Barrier for prevention of bacterial transcytosis

10.1101/2021.06.20.449199 ◽

2021 ◽

Author(s):

Smita Bhutda ◽

Sourav Ghosh ◽

Akash Raj Sinha ◽

Shweta Santra ◽

Aishwarya Hiray ◽

...

Keyword(s):

Blood Brain Barrier ◽

Time Lapse ◽

Brain Barrier ◽

Effective Strategy ◽

Brain Endothelium ◽

Defence Mechanisms ◽

Protective Mechanisms ◽

Blood Brain ◽

Major Route ◽

The Brain

The protective mechanisms of blood-brain barrier (BBB) prohibiting entry of blood borne pathogens and toxins into the central nervous system (CNS) is critical for maintenance of homeostasis in the brain. These include various forms of intracellular defence mechanisms which are vital to block bacterial transcytosis, the major route of trafficking adopted by meningeal pathogens to transit into the CNS. However, mechanistic details of the defence mechanisms and their exploitation to prevent bacterial meningitis remain unexplored. In this study, we established that brain endothelium driven ubiquitination acts as a major intracellular defence mechanism for clearance of S. pneumoniae, a critical neurotropic pathogen, during its transit through BBB. Our findings suggest that brain endothelium employs differential ubiquitination with either K48 or K63-Ub chain topologies as an effective strategy to target SPN towards diverse killing pathways. While K63-Ub decoration triggers autophagic killing, K48-Ub directs pneumococcus exclusively to the proteasome machinery. Indeed, time lapse fluorescence imaging involving proteasomal marker LMP2 revealed that in BBB, majority of the ubiquitinated SPN were cleared by proteasome. Fittingly, pharmacological inhibition of proteasome and autophagy pathway not only led to exclusive accumulation of K48-Ub and K63-Ub marked SPN, respectively, but also triggered significant increment in intracellular SPN burden. Moreover, genetic impairment of formation of either K48 or K63-Ub chain topology demonstrated that though both chain types play important roles in disposal of intracellular SPN, K48-Ub chains and subsequent proteasomal degradation has more pronounced contribution towards ubiquitinated SPN killing in brain endothelium. Collectively, these observations for the first time illustrated a pivotal role of differential ubiquitination in orchestrating a symphony of intracellular defence mechanisms blocking pathogen trafficking into the brain which could be further exploited to prevent bacterial CNS infections.

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Cannabinoid receptor 2 agonist attenuates blood‑brain barrier damage in a rat model of intracerebral hemorrhage by activating the Rac1 pathway

International Journal of Molecular Medicine ◽

10.3892/ijmm.2018.3834 ◽

2018 ◽

Cited By ~ 1

Author(s):

Zhe Wang ◽

Yongfu Li ◽

Shuangyong Cai ◽

Rui Li ◽

Guanbo Cao

Keyword(s):

Intracerebral Hemorrhage ◽

Blood Brain Barrier ◽

Rat Model ◽

Cannabinoid Receptor ◽

Brain Barrier ◽

Cannabinoid Receptor 2 ◽

Blood Brain ◽

Blood Brain Barrier Damage

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Ligand and Structure-based Modeling of Passive Diffusion through the Blood-Brain Barrier

Current Medicinal Chemistry ◽

10.2174/0929867324666171106163742 ◽

2018 ◽

Vol 25 (9) ◽

pp. 1073-1089 ◽

Cited By ~ 1

Author(s):

Santiago Vilar ◽

Eduardo Sobarzo-Sanchez ◽

Lourdes Santana ◽

Eugenio Uriarte

Keyword(s):

Blood Brain Barrier ◽

In Silico ◽

Passive Diffusion ◽

Brain Barrier ◽

Barrier Permeability ◽

Blood Brain Barrier Permeability ◽

Blood Brain ◽

Brain Barrier Permeability ◽

Different Types ◽

The Brain

Background: Blood-brain barrier transport is an important process to be considered in drug candidates. The blood-brain barrier protects the brain from toxicological agents and, therefore, also establishes a restrictive mechanism for the delivery of drugs into the brain. Although there are different and complex mechanisms implicated in drug transport, in this review we focused on the prediction of passive diffusion through the blood-brain barrier. Methods: We elaborated on ligand-based and structure-based models that have been described to predict the blood-brain barrier permeability. Results: Multiple 2D and 3D QSPR/QSAR models and integrative approaches have been published to establish quantitative and qualitative relationships with the blood-brain barrier permeability. We explained different types of descriptors that correlate with passive diffusion along with data analysis methods. Moreover, we discussed the applicability of other types of molecular structure-based simulations, such as molecular dynamics, and their implications in the prediction of passive diffusion. Challenges and limitations of experimental measurements of permeability and in silico predictive methods were also described. Conclusion: Improvements in the prediction of blood-brain barrier permeability from different types of in silico models are crucial to optimize the process of Central Nervous System drug discovery and development.

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