Neurons and ECM regulate occludin localization in brain endothelial cells

Savettieri, Giovanni; Liegro, Italia Di; Catania, Caterina; Licata, Luana; Pitarresi, Giovanna; D’Agostino, Stefania; Schiera, Gabriella; De, Viviana; Giandalia, Giulia; Giannola, Libero Italo; Cestelli, Alessandro

doi:10.1097/00001756-200004070-00035

Cited by 113 publications

(88 citation statements)

References 6 publications

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“…It also implies that endothelial cells in the in vitro model may be more sensitive to H and H/R due to the lack of pericytes, glia, and neurons, which constitute the intact neurovascular unit. This concept is supported by studies (2,27,42,43) that show that endothelial cells co-cultured with glia and/or neurons respond differently to stimuli than do endothelial cells cultured alone. A second explanation for the differences between the in vitro and in vivo H models may be the level of H and duration of the hypoxic exposure.…”

Section: Discussionmentioning

confidence: 87%

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Fleegal

Hom

Borg

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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-The blood-brain barrier (BBB) is a metabolic and physiological barrier important for maintaining brain homeostasis. The aim of this study was to determine the role of PKC activation in BBB paracellular permeability changes induced by hypoxia and posthypoxic reoxygenation using in vitro and in vivo BBB models. In rat brain microvessel endothelial cells (RMECs) exposed to hypoxia (1% O 2-99% N2; 24 h), a significant increase in total PKC activity was observed, and this was reduced by posthypoxic reoxygenation (95% room air-5% CO 2) for 2 h. The expression of PKC-␤II, PKC-␥, PKC-, PKC-, and PKC-also increased following hypoxia (1% O 2-99% N2; 24 h), and these protein levels remained elevated following posthypoxic reoxygenation (95% room air-5% CO 2; 2 h). Increases in the expression of PKC-⑀ and PKC-were also observed following posthypoxic reoxygenation (95% room air-5% CO 2; 2 h). Moreover, inhibition of PKC with chelerythrine chloride (10 M) attenuated the hypoxiainduced increases in [ 14 C]sucrose permeability. Similar to what was observed in RMECs, total PKC activity was also stimulated in cerebral microvessels isolated from rats exposed to hypoxia (6% O 2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min). In contrast, hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min) significantly increased the expression levels of only PKC-␥ and PKC-in the in vivo hypoxia model. These data demonstrate that hypoxia-induced BBB paracellular permeability changes occur via a PKC-dependent mechanism, possibly by differentially regulating the protein expression of the 11 PKC isozymes. protein kinase C; paracellular; neurovascular unit; rat THE BLOOD-BRAIN BARRIER (BBB) is a metabolic and physiological barrier important for maintaining cerebral homeostasis. Brain microvessels that form the BBB are lined with specialized endothelial cells surrounded by pericytes, astroglial processes, and the extracellular matrix. Compared with the peripheral microvasculature, cerebral microvessels are highly specialized because they lack vesicular transport and fenestrations while having a high level of metabolic activity. This lack of fenestrations is due to the presence of tight junctions (TJ) and adherens junctions, which restrict paracellular movement of molecules across the BBB (29,31,40).Stroke is a leading cause of death and disability in the United States (3). It has been demonstrated that the BBB is compromised during stroke (29). The effects of stroke on the cerebral vasculature significantly contribute to the brain damage caused by stroke. It has been determined that the lack of oxygen (hypoxia, H) followed by reperfusion (posthypoxic reoxygenation, H/R) during stroke contributes to both neuronal and vascular damage. Both H and H/R cause increases in cerebrovascular permeability with concomitant increases in vasogenic cerebral edema (1,36,47).Previous studies (36, 47) have demonstrated that H and H/R cause changes in paracellular permeability to [ 14 C]sucrose in cerebral vascular endothelial cells....

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Section: Discussionmentioning

confidence: 87%

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Fleegal

Hom

Borg

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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“…We previously found that both neurons (24,27,28) and astrocytes (23,24) influence the ability of endothelial cells to form a barrier with properties resembling those of BBB. In the present study, we used an already described BBB in vitro model (23,24) to investigate whether the serum from patients with secondary progressive multiple sclerosis (SPMS) (29) caused any alteration of the neuronal vitality and morphology, and/or any BBB damage.…”

Section: Resultsmentioning

confidence: 99%

“…Cells were homogenized in homogenization buffer (0.32 M sucrose; 50 mM sodium phosphate buffer, pH 6.5; 50 mM KCl, 0.5 mM spermine; 0.15 mM spermidine; 2 mM EDTA, and 0.15 mM EGTA), containing the protease inhibitors aprotinin (2 μg/ml), antipain (2 μg/ml), leupeptin (2 μg/ml), pepstatin A (2 μg/ml), benzamidine (1.0 mM) and phenylmethylsulfonyl fluoride (1.0 mM), all purchased from Sigma-Aldrich. Proteins (20 μg of total cell extracts) were separated by electrophoresis on denaturing 10% polyacrylamide slab gels (SDS-PAGE) and immunoblotted as described elsewhere (27). The membranes were immunostained with goat polyclonal anti-occludin N19 antibodies (Santa Cruz).…”

Section: Methodsmentioning

confidence: 99%

Neuronal and BBB damage induced by sera from patients with secondary progressive multiple sclerosis

Proia

Schiera²,

Salemi³

et al. 2009

Int J Mol Med

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Abstract. An important component of the pathogenic process of multiple sclerosis (MS) is the blood-brain barrier (BBB) damage. We recently set an in vitro model of BBB, based on a three-cell-type co-culture system, in which rat neurons and astrocytes synergistically induce brain capillary endothelial cells to form a monolayer with permeability properties resembling those of the physiological BBB. Herein we report that the serum from patients with secondary progressive multiple sclerosis (SPMS) has a damaging effect on isolated neurons. This finding suggests that neuronal damaging in MS could be a primary event and not only secondary to myelin damage, as generally assumed. SPMS serum affects the permeability of the BBB model, as indicated by the decrease of the transendothelial electrical resistance (TEER). Moreover, as shown by both immunofluorescence and Western blot analyses, BBB breaking is accompanied by a decrease of the synthesis as well as the peripheral localization of occludin, a structural protein of the tight junctions that are responsible for BBB properties.

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“…There is some evidence that neurons contribute directly to the induction of tight junction formation during development. Proper targeting of occludin, one of the proteins that constitute tight junctions in endothelial cells, to the cell periphery has been shown to occur only after co-culture with neurons [133]. There is evidence for a synergistic effect on tight junction formation when astrocytes and neurons are cultured with endothelial cells [134].…”

Section: B Tight Junction Proteinsmentioning

confidence: 99%

“…There is evidence for a synergistic effect on tight junction formation when astrocytes and neurons are cultured with endothelial cells [134]. Neurons in combination with extracellular matrix components can also play a role in regulation of occludin expression [133]. Neuronal activity is closely coupled with astrocyte and blood vessel functions in the brain.…”

Section: B Tight Junction Proteinsmentioning

confidence: 99%

Biomedical Technologies for In Vitro Screening and Controlled Delivery of Neuroactive Compounds

Frampton¹,

Shuler²,

Shain³

et al. 2008

CNSAMC

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Cell culture models can provide information pertaining to the effective dose, toxiciology, and kinetics, for a variety of neuroactive compounds. However, many in vitro models fail to adequately predict how such compounds will perform in a living organism. At the systems level, interactions between organs can dramatically affect the properties of a compound by alteration of its biological activity or by elimination of it from the body. At the tissue level, interaction between cell types can alter the transport properties of a particular compound, or can buffer its effects on target cells by uptake, processing, or changes in chemical signaling between cells. In any given tissue, cells exist in a three-dimensional environment bounded on all sides by other cells and components of the extracellular matrix, providing kinetics that are dramatically different from the kinetics in traditional two-dimensional cell culture systems. Cell culture analogs are currently being developed to better model the complex transport and processing that occur prior to drug uptake in the CNS, and to predict blood-brain barrier permeability. These approaches utilize microfluidics, hydrogel matrices, and a variety of cell types (including lung epithelial cells, hepatocytes, adipocytes, glial cells, and neurons) to more accurately model drug transport and biological activity. Similar strategies are also being used to control both the spatial and temporal release of therapeutic compounds for targeted treatment of CNS disease.

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Neurons and ECM regulate occludin localization in brain endothelial cells

Cited by 113 publications

References 6 publications

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Neuronal and BBB damage induced by sera from patients with secondary progressive multiple sclerosis

Biomedical Technologies for In Vitro Screening and Controlled Delivery of Neuroactive Compounds

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