scholarly journals The pericyte–glia interface at the blood–brain barrier

2018 ◽  
Vol 132 (3) ◽  
pp. 361-374 ◽  
Author(s):  
Patrizia Giannoni ◽  
Jerome Badaut ◽  
Cyril Dargazanli ◽  
Alexis Fayd’Herbe De Maudave ◽  
Wendy Klement ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Glial Cells ◽  
Outer Wall ◽  
Brain Barrier ◽  
Capillary Endothelium ◽  
Brain Capillary ◽  
Multicellular Structure ◽  
Blood Brain ◽  
Acute Insult ◽  
The Brain

The cerebrovasculature is a multicellular structure with varying rheological and permeability properties. The outer wall of the brain capillary endothelium is enclosed by pericytes and astrocyte end feet, anatomically assembled to guarantee barrier functions. We, here, focus on the pericyte modifications occurring in disease conditions, reviewing evidence supporting the interplay amongst pericytes, the endothelium, and glial cells in health and pathology. Deconstruction and reactivity of pericytes and glial cells around the capillary endothelium occur in response to traumatic brain injury, epilepsy, and neurodegenerative disorders, impacting vascular permeability and participating in neuroinflammation. As this represents a growing field of research, addressing the multicellular reorganization occurring at the outer wall of the blood-brain barrier (BBB) in response to an acute insult or a chronic disease could disclose novel disease mechanisms and therapeutic targets.

Modulation of p-Glycoprotein Transport Function at the Blood-Brain Barrier

2005 ◽  
Vol 230 (2) ◽  
pp. 118-127 ◽  
Author(s):  
Björn Bauer ◽  
Anika M. S. Hartz ◽  
Gert Fricker ◽  
David S. Miller
Keyword(s):  
Blood Brain Barrier ◽  
Viral Infections ◽  
Brain Barrier ◽  
Capillary Endothelium ◽  
Brain Capillary ◽  
P Glycoprotein ◽  
Blood Brain ◽  
Junctional Permeability ◽  
Capillary Endothelial Cells ◽  
The Brain

The central nervous system (CNS) effects of many therapeutic drugs are blunted because of restricted entry into the brain. The basis for this poor permeability is the brain capillary endothelium, which comprises the blood-brain barrier. This tissue exhibits very low paracellular (tight-junctional) permeability and expresses potent, multispecific, drug export pumps. Together, these combine to limit use of pharmacotherapy to treat CNS disorders such as brain cancer and bacterial or viral infections. Of all the xenobiotic efflux pumps highly expressed in brain capillary endothelial cells, p-glycoprotein handles the largest fraction of commonly prescribed drugs and thus is an obvious target for manipulation. Here we review recent studies focused on understanding the mechanisms by which p-glycoprotein activity in the blood-brain barrier can be modulated. These include (i) direct inhibition by specific competitors, (ii) functional modulation, and (iii) transcriptional modulation. Each has the potential to specifically reduce p-glycoprotein function and thus selectively increase brain permeability of p-glycoprotein substrates.

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.

Changes in the glucose transporter of brain capillaries

1992 ◽  
Vol 70 (S1) ◽  
pp. S113-S117 ◽  
Author(s):  
Sami I. Harik
Keyword(s):  
Alzheimer Disease ◽  
Blood Brain Barrier ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Brain Barrier ◽  
Capillary Endothelium ◽  
Brain Capillaries ◽  
Glut 1 ◽  
Blood Brain ◽  
The Brain

Brain capillary endothelium has a high density of the GLUT-1 facilitative glucose transporter protein. This is reasonable in view of the brain's high metabolic rate for glucose and its isolation behind unique capillaries with blood – brain barrier properties. Thus, the brain endothelium, which constitutes less than 0.1% of the brain weight, has to transport glucose for the much larger mass of surrounding neurons and glia. I describe here the changes that occur in the density of glucose transporters in brain capillaries of subjects with Alzheimer disease, where there is a decreased cerebral metabolic rate for glucose, and in a novel clinical entity characterized by defective glucose transport at the blood – brain barrier. In subjects with Alzheimer disease, cerebral microvessels showed a marked decrease in the density of the glucose transporter when compared with age-matched controls, but there was no change in the density of glucose transporters in erythrocyte membranes. Thus, I believe that the decreased density of glucose transporters in the brains of subjects with Alzheimer disease is the result rather than the cause of the disease. In contradistinction, the primary defect in glucose transport at the blood – brain barrier in subjects with the recently described entity is associated with decreased density of GLUT-1 in erythrocyte membranes.Key words: brain microvessels, capillary endothelium, blood – brain barrier, glucose transporter, Alzheimer disease, hypoglycorrhachia.

Induction of blood-brain barrier properties in cultured brain capillary endothelial cells: Comparison between primary glial cells and C6 cell line

Glia ◽  
2005 ◽  
Vol 51 (3) ◽  
pp. 187-198 ◽  
Author(s):  
Monica Boveri ◽  
Vincent Berezowski ◽  
Anna Price ◽  
Stephanie Slupek ◽  
Anne-Marie Lenfant ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Line ◽  
Blood Brain Barrier ◽  
Glial Cells ◽  
Barrier Properties ◽  
Brain Barrier ◽  
Brain Capillary ◽  
Blood Brain ◽  
Capillary Endothelial Cells ◽  
C6 Cell Line

scholarly journals Plasticity of Carbohydrate Transport at the Blood-Brain Barrier

2021 ◽  
Vol 14 ◽  
Author(s):  
Ellen McMullen ◽  
Astrid Weiler ◽  
Holger M. Becker ◽  
Stefanie Schirmeier
Keyword(s):  
Nervous System ◽  
Rna Interference ◽  
Blood Brain Barrier ◽  
Glial Cells ◽  
Major Facilitator Superfamily ◽  
Brain Barrier ◽  
Blood Brain ◽  
Carbohydrate Transport ◽  
The Brain ◽  
Null Mutants

Neuronal function is highly energy demanding, requiring efficient transport of nutrients into the central nervous system (CNS). Simultaneously the brain must be protected from the influx of unwanted solutes. Most of the energy is supplied from dietary sugars, delivered from circulation via the blood-brain barrier (BBB). Therefore, selective transporters are required to shuttle metabolites into the nervous system where they can be utilized. The Drosophila BBB is formed by perineural and subperineurial glial cells, which effectively separate the brain from the surrounding hemolymph, maintaining a constant microenvironment. We identified two previously unknown BBB transporters, MFS3 (Major Facilitator Superfamily Transporter 3), located in the perineurial glial cells, and Pippin, found in both the perineurial and subperineurial glial cells. Both transporters facilitate uptake of circulating trehalose and glucose into the BBB-forming glial cells. RNA interference-mediated knockdown of these transporters leads to pupal lethality. However, null mutants reach adulthood, although they do show reduced lifespan and activity. Here, we report that both carbohydrate transport efficiency and resulting lethality found upon loss of MFS3 or Pippin are rescued via compensatory upregulation of Tret1-1, another BBB carbohydrate transporter, in Mfs3 and pippin null mutants, while RNAi-mediated knockdown is not compensated for. This means that the compensatory mechanisms in place upon mRNA degradation following RNA interference can be vastly different from those resulting from a null mutation.

scholarly journals A New Function for the LDL Receptor: Transcytosis of LDL across the Blood–Brain Barrier

1997 ◽  
Vol 138 (4) ◽  
pp. 877-889 ◽  
Author(s):  
Bénédicte Dehouck ◽  
Laurence Fenart ◽  
Marie-Pierre Dehouck ◽  
Annick Pierce ◽  
Gérard Torpier ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Cytoplasmic Domain ◽  
Brain Barrier ◽  
Classical Pathway ◽  
Brain Capillary ◽  
Blood Brain ◽  
The Brain

Lipoprotein transport across the blood–brain barrier (BBB) is of critical importance for the delivery of essential lipids to the brain cells. The occurrence of a low density lipoprotein (LDL) receptor on the BBB has recently been demonstrated. To examine further the function of this receptor, we have shown using an in vitro model of the BBB, that in contrast to acetylated LDL, which does not cross the BBB, LDL is specifically transcytosed across the monolayer. The C7 monoclonal antibody, known to interact with the LDL receptor-binding domain, totally blocked the transcytosis of LDL, suggesting that the transcytosis is mediated by the receptor. Furthermore, we have shown that cholesterol-depleted astrocytes upregulate the expression of the LDL receptor at the BBB. Under these conditions, we observed that the LDL transcytosis parallels the increase in the LDL receptor, indicating once more that the LDL is transcytosed by a receptor-mediated mechanism. The nondegradation of the LDL during the transcytosis indicates that the transcytotic pathway in brain capillary endothelial cells is different from the LDL receptor classical pathway. The switch between a recycling receptor to a transcytotic receptor cannot be explained by a modification of the internalization signals of the cytoplasmic domain of the receptor, since we have shown that LDL receptor messengers in growing brain capillary ECs (recycling LDL receptor) or differentiated cells (transcytotic receptor) are 100% identical, but we cannot exclude posttranslational modifications of the cytoplasmic domain, as demonstrated for the polymeric immunoglobulin receptor. Preliminary studies suggest that caveolae are likely to be involved in the potential transport of LDL from the blood to the brain.

scholarly journals The Role of Cytoskeletal Proteins in the Formation of a Functional In Vitro Blood-Brain Barrier Model

2022 ◽  
Vol 23 (2) ◽  
pp. 742
Author(s):  
Shireen Mentor ◽  
Khayelihle Brian Makhathini ◽  
David Fisher
Keyword(s):  
Blood Brain Barrier ◽  
Cellular Proliferation ◽  
Cytoskeletal Proteins ◽  
Brain Barrier ◽  
Capillary Endothelium ◽  
Brain Capillary ◽  
Blood Brain ◽  
Blood Brain Barrier Model

The brain capillary endothelium is highly regulatory, maintaining the chemical stability of the brain’s microenvironment. The role of cytoskeletal proteins in tethering nanotubules (TENTs) during barrier-genesis was investigated using the established immortalized mouse brain endothelial cell line (bEnd5) as an in vitro blood-brain barrier (BBB) model. The morphology of bEnd5 cells was evaluated using both high-resolution scanning electron microscopy and immunofluorescence to evaluate treatment with depolymerizing agents Cytochalasin D for F-actin filaments and Nocodazole for α-tubulin microtubules. The effects of the depolymerizing agents were investigated on bEnd5 monolayer permeability by measuring the transendothelial electrical resistance (TEER). The data endorsed that during barrier-genesis, F-actin and α-tubulin play a cytoarchitectural role in providing both cell shape dynamics and cytoskeletal structure to TENTs forming across the paracellular space to provide cell-cell engagement. Western blot analysis of the treatments suggested a reduced expression of both proteins, coinciding with a reduction in the rates of cellular proliferation and decreased TEER. The findings endorsed that TENTs provide alignment of the paracellular (PC) spaces and tight junction (TJ) zones to occlude bEnd5 PC spaces. The identification of specific cytoskeletal structures in TENTs endorsed the postulate of their indispensable role in barrier-genesis and the maintenance of regulatory permeability across the BBB.

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