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The inner CSF-brain barrier: developmentally controlled access to the brain via intercellular junctions.

Whish S, Dziegielewska KM, Møllgård K, Noor NM, Liddelow SA, Habgood MD, Richardson SJ, Saunders NR - Front Neurosci (2015)

Bottom Line: These intercellular connections do not provide a diffusional restrain between the two compartments.Claudin-11 was only immunopositive in the adult, consistent with results obtained from transcriptomic analysis.These results provide information about physiological, molecular and morphological-related permeability changes occurring at the inner cerebrospinal fluid-brain barrier during brain development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Therapeutics, University of Melbourne Parkville, VIC, Australia.

ABSTRACT
In the adult the interface between the cerebrospinal fluid and the brain is lined by the ependymal cells, which are joined by gap junctions. These intercellular connections do not provide a diffusional restrain between the two compartments. However, during development this interface, initially consisting of neuroepithelial cells and later radial glial cells, is characterized by "strap" junctions, which limit the exchange of different sized molecules between cerebrospinal fluid and the brain parenchyma. Here we provide a systematic study of permeability properties of this inner cerebrospinal fluid-brain barrier during mouse development from embryonic day, E17 until adult. Results show that at fetal stages exchange across this barrier is restricted to the smallest molecules (286Da) and the diffusional restraint is progressively removed as the brain develops. By postnatal day P20, molecules the size of plasma proteins (70 kDa) diffuse freely. Transcriptomic analysis of junctional proteins present in the cerebrospinal fluid-brain interface showed expression of adherens junctional proteins, actins, cadherins and catenins changing in a development manner consistent with the observed changes in the permeability studies. Gap junction proteins were only identified in the adult as was claudin-11. Immunohistochemistry was used to localize at the cellular level some of the adherens junctional proteins of genes identified from transcriptomic analysis. N-cadherin, β - and α-catenin immunoreactivity was detected outlining the inner CSF-brain interface from E16; most of these markers were not present in the adult ependyma. Claudin-5 was present in the apical-most part of radial glial cells and in endothelial cells in embryos, but only in endothelial cells including plexus endothelial cells in adults. Claudin-11 was only immunopositive in the adult, consistent with results obtained from transcriptomic analysis. These results provide information about physiological, molecular and morphological-related permeability changes occurring at the inner cerebrospinal fluid-brain barrier during brain development.

No MeSH data available.


Related in: MedlinePlus

Injection of biotin dextran amines into the ventricular system of mice. Schematic diagrams (A,B) and images (C,D) illustrating the methods used to inject dextrans into the lateral ventricles of mouse brain. (A) Micropipette injection of dextran into lateral ventricle. (B) Illustrates surface landmarks for injection site. (C) Distribution of dextran following injection. (D) Method used to measure diffusion distance of dextrans (red) using ImageJ64. Mean of 10 measurements, spanning the ventricular zone at right angles to ventricular surface (arrows). Scale bars 500 μm in (C,D). L, length; W, width.
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Figure 1: Injection of biotin dextran amines into the ventricular system of mice. Schematic diagrams (A,B) and images (C,D) illustrating the methods used to inject dextrans into the lateral ventricles of mouse brain. (A) Micropipette injection of dextran into lateral ventricle. (B) Illustrates surface landmarks for injection site. (C) Distribution of dextran following injection. (D) Method used to measure diffusion distance of dextrans (red) using ImageJ64. Mean of 10 measurements, spanning the ventricular zone at right angles to ventricular surface (arrows). Scale bars 500 μm in (C,D). L, length; W, width.

Mentions: Rhodamine–conjugated biotinylated dextran amines, BDAs, of molecular masses 3000 Da (3 kDa), 10000 Da (10 kDa) and 70000Da (70 kDa) and a 286 Da biotin ethylenediamine hydrobromide (BED) obtained from Molecular Probes (USA) were used in these experiments. Three to four individual mice from at least two separate litters were obtained for each experiment. All probes were diluted in sterile saline (25 mgml−1) and were injected into the right ventricle of anesthetized animals via a glass microcapillary and gentle pressure (see Figure 1). Injected volumes are listed in Table 1. Following injection the markers were allowed to distribute for a further 2–3 min (fetal), 5 min (postnatal ages to P20) or 10 min (adults) so that each dextran would flow into the contralateral ventricle. Brains of animals injected with fluorescence BDAs were dissected out from the skull and fixed by immersion in 4% paraformaldehyde (PFA) for 24 h at 4°C. Brains from pups injected with BED were fixed in Bouin's fixative for 24 h and processed for paraffin embedding (see below).


The inner CSF-brain barrier: developmentally controlled access to the brain via intercellular junctions.

Whish S, Dziegielewska KM, Møllgård K, Noor NM, Liddelow SA, Habgood MD, Richardson SJ, Saunders NR - Front Neurosci (2015)

Injection of biotin dextran amines into the ventricular system of mice. Schematic diagrams (A,B) and images (C,D) illustrating the methods used to inject dextrans into the lateral ventricles of mouse brain. (A) Micropipette injection of dextran into lateral ventricle. (B) Illustrates surface landmarks for injection site. (C) Distribution of dextran following injection. (D) Method used to measure diffusion distance of dextrans (red) using ImageJ64. Mean of 10 measurements, spanning the ventricular zone at right angles to ventricular surface (arrows). Scale bars 500 μm in (C,D). L, length; W, width.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325900&req=5

Figure 1: Injection of biotin dextran amines into the ventricular system of mice. Schematic diagrams (A,B) and images (C,D) illustrating the methods used to inject dextrans into the lateral ventricles of mouse brain. (A) Micropipette injection of dextran into lateral ventricle. (B) Illustrates surface landmarks for injection site. (C) Distribution of dextran following injection. (D) Method used to measure diffusion distance of dextrans (red) using ImageJ64. Mean of 10 measurements, spanning the ventricular zone at right angles to ventricular surface (arrows). Scale bars 500 μm in (C,D). L, length; W, width.
Mentions: Rhodamine–conjugated biotinylated dextran amines, BDAs, of molecular masses 3000 Da (3 kDa), 10000 Da (10 kDa) and 70000Da (70 kDa) and a 286 Da biotin ethylenediamine hydrobromide (BED) obtained from Molecular Probes (USA) were used in these experiments. Three to four individual mice from at least two separate litters were obtained for each experiment. All probes were diluted in sterile saline (25 mgml−1) and were injected into the right ventricle of anesthetized animals via a glass microcapillary and gentle pressure (see Figure 1). Injected volumes are listed in Table 1. Following injection the markers were allowed to distribute for a further 2–3 min (fetal), 5 min (postnatal ages to P20) or 10 min (adults) so that each dextran would flow into the contralateral ventricle. Brains of animals injected with fluorescence BDAs were dissected out from the skull and fixed by immersion in 4% paraformaldehyde (PFA) for 24 h at 4°C. Brains from pups injected with BED were fixed in Bouin's fixative for 24 h and processed for paraffin embedding (see below).

Bottom Line: These intercellular connections do not provide a diffusional restrain between the two compartments.Claudin-11 was only immunopositive in the adult, consistent with results obtained from transcriptomic analysis.These results provide information about physiological, molecular and morphological-related permeability changes occurring at the inner cerebrospinal fluid-brain barrier during brain development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Therapeutics, University of Melbourne Parkville, VIC, Australia.

ABSTRACT
In the adult the interface between the cerebrospinal fluid and the brain is lined by the ependymal cells, which are joined by gap junctions. These intercellular connections do not provide a diffusional restrain between the two compartments. However, during development this interface, initially consisting of neuroepithelial cells and later radial glial cells, is characterized by "strap" junctions, which limit the exchange of different sized molecules between cerebrospinal fluid and the brain parenchyma. Here we provide a systematic study of permeability properties of this inner cerebrospinal fluid-brain barrier during mouse development from embryonic day, E17 until adult. Results show that at fetal stages exchange across this barrier is restricted to the smallest molecules (286Da) and the diffusional restraint is progressively removed as the brain develops. By postnatal day P20, molecules the size of plasma proteins (70 kDa) diffuse freely. Transcriptomic analysis of junctional proteins present in the cerebrospinal fluid-brain interface showed expression of adherens junctional proteins, actins, cadherins and catenins changing in a development manner consistent with the observed changes in the permeability studies. Gap junction proteins were only identified in the adult as was claudin-11. Immunohistochemistry was used to localize at the cellular level some of the adherens junctional proteins of genes identified from transcriptomic analysis. N-cadherin, β - and α-catenin immunoreactivity was detected outlining the inner CSF-brain interface from E16; most of these markers were not present in the adult ependyma. Claudin-5 was present in the apical-most part of radial glial cells and in endothelial cells in embryos, but only in endothelial cells including plexus endothelial cells in adults. Claudin-11 was only immunopositive in the adult, consistent with results obtained from transcriptomic analysis. These results provide information about physiological, molecular and morphological-related permeability changes occurring at the inner cerebrospinal fluid-brain barrier during brain development.

No MeSH data available.


Related in: MedlinePlus