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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.


Diffusion of different sized rhodamine labeled biotinylated dextrans (BDA) into postnatal mouse brain. Vibratome coronal sections (80 μm thick) through cortex of mice injected with different sized BDAs (3, 10, and 70 kDa). Markers were injected into the contralateral ventricle and left to diffuse for 2–3 min at E19 and P0, 5 min at P10 and 10 min in the adult. Note that none of the dextrans entered the brain at E19. In older brains there was a progressive increase in penetration depending on the size of the dextran. By adulthood all three dextrans were entering the brain to a similar extent. Apparent diffusion distances shown in Figure 4. Distribution of BED (286 Da) is illustrated in Figure 2 for comparison. E, embryonic day; P, postnatal day. Scale bar 500 μm.
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Figure 3: Diffusion of different sized rhodamine labeled biotinylated dextrans (BDA) into postnatal mouse brain. Vibratome coronal sections (80 μm thick) through cortex of mice injected with different sized BDAs (3, 10, and 70 kDa). Markers were injected into the contralateral ventricle and left to diffuse for 2–3 min at E19 and P0, 5 min at P10 and 10 min in the adult. Note that none of the dextrans entered the brain at E19. In older brains there was a progressive increase in penetration depending on the size of the dextran. By adulthood all three dextrans were entering the brain to a similar extent. Apparent diffusion distances shown in Figure 4. Distribution of BED (286 Da) is illustrated in Figure 2 for comparison. E, embryonic day; P, postnatal day. Scale bar 500 μm.

Mentions: The permeability characteristics of the CSF–brain barrier were investigated using three different sized biotinylated dextran amines conjugated with rhodamine: 3, 10, and 70 kDa. In addition a small marker of 268 Da (BED) was used in fetal animals at E17, E19, and in P0. All animals, from E17 to adult, received an injection of 25 mg ml−1 of marker in sterile saline into one lateral ventricle as described in the Materials and Methods. Vibratome and paraffin-embedded microtome-cut sections from the ventricle contralateral to the injected side were analyzed. Results are illustrated in Figures 2, 3 and summarized in Figure 4.


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)

Diffusion of different sized rhodamine labeled biotinylated dextrans (BDA) into postnatal mouse brain. Vibratome coronal sections (80 μm thick) through cortex of mice injected with different sized BDAs (3, 10, and 70 kDa). Markers were injected into the contralateral ventricle and left to diffuse for 2–3 min at E19 and P0, 5 min at P10 and 10 min in the adult. Note that none of the dextrans entered the brain at E19. In older brains there was a progressive increase in penetration depending on the size of the dextran. By adulthood all three dextrans were entering the brain to a similar extent. Apparent diffusion distances shown in Figure 4. Distribution of BED (286 Da) is illustrated in Figure 2 for comparison. E, embryonic day; P, postnatal day. Scale bar 500 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Diffusion of different sized rhodamine labeled biotinylated dextrans (BDA) into postnatal mouse brain. Vibratome coronal sections (80 μm thick) through cortex of mice injected with different sized BDAs (3, 10, and 70 kDa). Markers were injected into the contralateral ventricle and left to diffuse for 2–3 min at E19 and P0, 5 min at P10 and 10 min in the adult. Note that none of the dextrans entered the brain at E19. In older brains there was a progressive increase in penetration depending on the size of the dextran. By adulthood all three dextrans were entering the brain to a similar extent. Apparent diffusion distances shown in Figure 4. Distribution of BED (286 Da) is illustrated in Figure 2 for comparison. E, embryonic day; P, postnatal day. Scale bar 500 μm.
Mentions: The permeability characteristics of the CSF–brain barrier were investigated using three different sized biotinylated dextran amines conjugated with rhodamine: 3, 10, and 70 kDa. In addition a small marker of 268 Da (BED) was used in fetal animals at E17, E19, and in P0. All animals, from E17 to adult, received an injection of 25 mg ml−1 of marker in sterile saline into one lateral ventricle as described in the Materials and Methods. Vibratome and paraffin-embedded microtome-cut sections from the ventricle contralateral to the injected side were analyzed. Results are illustrated in Figures 2, 3 and summarized in Figure 4.

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.