Molecular Anatomy of the Blood-Brain Barrier as Defined by Immunocytochemistry

Dermietzel, Rolf; Krause, Dorothee

doi:10.1016/s0074-7696(08)60692-0

Cited by 224 publications

(108 citation statements)

References 199 publications

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“…It was shown to be a cytoplasmic component of adherens junctions (Itoh et al, 1991(Itoh et al, , 1993Howarth et al, 1992), as well as gap junctions (Thomas et al, 2002). Studies of ZO-1 in the CNS have indicated restricted expression patterns, with localization to vascular, circumventricular and developing neuroepithelial cell types (Dermietzel and Krause, 1991;Howarth et al, 1992;Smith and Shine, 1992;Petrov et al, 1994;Aaku-Saraste et al, 1996;Saitou et al, 1997;Wolburg and Lippoldt, 2002;Vorbrodt and Dobrogowska, 2003), and a few types of neurons in the olfactory system and hippocampus (Miragall et al, 1994;Inagaki et al, 2003). However, we have found a much wider distribution of ZO-1 in the CNS, including its localization at inter-neuronal gap junctions composed of Cx36 (Li et al, 2004).…”

Section: Cx47 Association With Zo-1mentioning

confidence: 99%

Connexin47, connexin29 and connexin32 co-expression in oligodendrocytes and cx47 association with zonula occludens-1 (zo-1) in mouse brain

2004

Neuroscience

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Gap junctions between glial cells in mammalian CNS are known to contain several connexins (Cx), including Cx26, Cx30 and Cx43 at astrocyte-to-astrocyte junctions, and Cx29 and Cx32 on the oligodendrocyte side of astrocyte-to-oligodendrocyte junctions. Recent reports indicating that oligodendrocytes also express Cx47 prompted the present studies of Cx47 localization and relationships to other glial connexins in mouse CNS. In view of the increasing number of connexins reported to interact directly with the scaffolding protein zonula occludens-1 (ZO-1), we investigated ZO-1 expression and Cx47/ZO-1 interaction capabilities in brain, spinal cord and Cx47-transfected HeLa cells. From counts of over 9000 oligodendrocytes labeled by immunofluorescence in various brain regions, virtually all of these cells were found to express Cx29, Cx32 and Cx47. Oligodendrocyte somata displayed robust Cx47-immunopositive puncta that were co-localized with punctate labeling for Cx32 and Cx43. By freeze-fracture replica immunogold labeling, Cx47 was abundant on the oligodendrocyte-side of oligodendrocyte/astrocyte gap junctions. By immunofluorescence, labeling for Cx47 along myelinated fibers was sparse in most brain regions, whereas Cx29 and Cx32 were previously found to be concentrated along these fibers. By immunogold labeling, Cx47 was found in numerous small gap junctions linking myelin to astrocytes, but not within deeper layers of myelin. Brain subcellular fractionation revealed a lack of Cx47 enrichment in myelin fractions, which nevertheless contained an enrichment of Cx32 and Cx29. Oligodendrocytes were immunopositive for ZO-1, and displayed almost total Cx47/ZO-1 colocalization. ZO-1 was found to co-immunoprecipitate with Cx47, and pull-down assays indicated binding of Cx47 to the second PDZ domain of ZO-1.Our results indicate widespread expression of Cx47 by oligodendrocytes, but with a distribution pattern in relative levels inverse to the abundance of Cx29 in myelin and paucity of Cx29 in oligodendrocyte somata. Further, our findings suggest a scaffolding and/or regulatory role of ZO-1 at the oligodendrocyte side of astrocyte-to-oligodendrocyte gap junctions. Keywords connexin47; connexin32; connexin43; gap junctions; PDZ domains; glia Gap junctions are localized at specialized cell-to-cell contacts of plasma membranes in which connexin (Cx) proteins form bidirectional intercellular channels that allow passage of ions and *Corresponding author. Tel: +1-204-789-3767; fax: +1-204-789-3934. E-mail address: nagyji@ms.umanitoba.ca (J. I. Nagy).. 1 Present address: Department of Pathology, Weifang Medical College, PR China. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2007 March 8. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptsmall molecules between cells (Goodenough et al., 1996;Kumar and Gilula, 1996;Willecke et al., 2002). In the CNS, astrocytes are extensively coupled by gap junctions (astrocyte-toastrocyte gap junctions [A/A junctions]) that, base...

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Section: Cx47 Association With Zo-1mentioning

confidence: 99%

Connexin47, connexin29 and connexin32 co-expression in oligodendrocytes and cx47 association with zonula occludens-1 (zo-1) in mouse brain

2004

Neuroscience

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“…26 The role of astrocytes as an integral part of the blood-brain barrier suggests that bilirubin toxicity to astrocytes could play an important role in blood-brain barrier integrity and bilirubin transport that leads to deeper neuronal injury and kernicterus. 27 It has also been shown that apoptosis can be induced in cultured neurons by removal of the neurotrophic support of astroglial cells. 28 Further studies are needed to better understand the effects of bilirubin on the interplay of maturation and injury in astrocytes and neurons.…”

Section: Discussionmentioning

confidence: 99%

Bilirubin Toxicity and Differentiation of Cultured Astrocytes

Rhine

Schmitter

et al. 1999

J Perinatol

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OBJECTIVE:To study the toxicity of bilirubin in primary cultures of newborn rat cerebral cortical astrocytes. STUDY DESIGN:Primary cultures of newborn rat astrocytes were incubated at bilirubin concentrations of 0, 1, 5, 10, 25, 50, 100, 200, and 2000 M, at a bilirubin:albumin molar ratio of 1.7. Bilirubin toxicity was determined by changes in cellular morphology, trypan blue staining, and lactate dehydrogenase (LDH) release into the culture medium at various times of incubation. To determine if differentiation of astrocytes affects bilirubin toxicity, cultures were treated with dibutyryl cyclic adenosine monophosphate. RESULTS:All three indices of toxicity showed a bilirubin concentration dependence. LDH release in experimental cultures was significantly elevated (p Ͻ 0.05) above that of control cultures by 24 hours at bilirubin concentrations of Ն100 M. The absolute amount of LDH release differed significantly between the 200 and 2000 M cultures from 1.5 to 24 hours, after which duration of exposure appeared to take over and all cultures approached maximum. LDH release for the lower concentrations all reached maximum by 120 hours, except for the 1 M cultures, which showed no significant elevation above control throughout the study period. At 100 and 200 M bilirubin, LDH release by untreated cells was significantly higher (p Ͻ 0.05) than release by treated cells by 36 hours. CONCLUSION:Undifferentiated astrocytes appeared to be more sensitive to bilirubin toxicity, which may correlate with the greater susceptibility of newborns to kernicteric injury. Studies with primary astrocyte culture may provide insight into how bilirubin sensitivity changes with brain development as well as the cellular and biochemical mechanisms of bilirubin encephalopathy.Hyperbilirubinemia-induced encephalopathy, i.e., kernicterus, has been well described. [1][2][3][4] However, the principal underlying mechanisms of bilirubin neurotoxicity have been much more difficult to determine despite extensive study. Currently, bilirubin is postulated to have a multifactorial role in cellular damage. Exposure to bilirubin has been associated with changes in energy metabolism; changes in carbohydrate, amino acid, and lipid metabolism; alteration in membrane function; decreased membrane potential; alteration in enzymatic function; and inhibition of protein and DNA synthesis. [1][2][3][4] Models that have been used to study these mechanisms include in vivo models such as hyperosmolar opening of the blood-brain barrier 5 and congenitally jaundiced rats, 3 or in vitro models, e.g., perfused brain sections, 6 synaptosome preparations, 7,8 neural-derived transformed cell lines, 9 and glial cell cultures. 10 -12 We chose to study bilirubin toxicity in primary culture of astrocytes.Investigation with primary culture of astrocytes has several advantages. It involves normal diploid cells with biochemical and morphologic features close to those found in vivo. 13 It is a simple system, consisting of a highly enriched preparation of astrocytes, 14 which elim...

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“…, 1990;Takata et aI. , 1990;Dermietzel and Krause, 1991;Farrell and Pardridge, 1991;Guerin et aI., 1992). The complete association of GLUTl with capillaries of barrier structures is in accordance with an exclusively vas cular location of GLUTl.…”

Section: Discussionmentioning

confidence: 99%

“…, 1990), and the area postrema and median eminence (Kalaria et aI. , 1988;Young and Wang, 1990;Dermietzel and Krause, 1991). Concerning the hypophysis, Gerhart et ai.…”

Section: Discussionmentioning

confidence: 99%

“…The glucose transporter type 1 (GLUTl) rep resents a specific carrier system that enables D-glu cose to be transferred from blood to brain (Bell et aI., 1990;Pessin and Bell, 1992). In various studies, the association between tight junctions and GLUTl staining has been demonstrated (Gerhart et aI., 1989;Kasanicki et aI., 1989;Harik et aI., 1990;Takata et aI., 1990;Dermietzel and Krause, 1991;Farrell and Pardridge, 1991). Less is known about the existence of GLUTl in brain structures with a "leaky" barrier, like the area postrema, subcom missural organ, median eminence, subfornical or gan, pituitary gland, and pineal gland.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Regional Congruence and Divergence of Glucose Transporters (GLUT1) and Capillaries in Rat Brains

Rahner-Welsch

Vogel

Kuschinsky

1995

J Cereb Blood Flow Metab

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Summary:The association of glucose transporters (GLUTl) and brain capillaries was tested in different brain structures of rats by a direct comparison of the topologies of capillaries and GLUTl in identical brain sections. Antibody staining of capillaries (fibronectin) and GLUTl were made visible by fluorescence micros copy. The results showed differences between brain structures containing a tight and a leaky blood-brain bar rier. All capillaries of brain structures with a tight blood brain barrier showed congruent staining of GLUTl and capillary morphology. The circumventricular organs that are known to have leaky barrier capillaries were stained

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Molecular Anatomy of the Blood-Brain Barrier as Defined by Immunocytochemistry

Cited by 224 publications

References 199 publications

Connexin47, connexin29 and connexin32 co-expression in oligodendrocytes and cx47 association with zonula occludens-1 (zo-1) in mouse brain

Connexin47, connexin29 and connexin32 co-expression in oligodendrocytes and cx47 association with zonula occludens-1 (zo-1) in mouse brain

Bilirubin Toxicity and Differentiation of Cultured Astrocytes

Regional Congruence and Divergence of Glucose Transporters (GLUT1) and Capillaries in Rat Brains

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