TY  - JOUR
A1  - Neuhaus, Winfried
A1  - Gaiser, Fabian
A1  - Mahringer, Anne
A1  - Franz, Jonas
A1  - Riethmüller, Christoph
A1  - Förster, Carola
T1  - The pivotal role of astrocytes in an in vitro stroke model of the blood-brain barrier
JF  - Frontiers in Cellular Neuroscience
N2  - Stabilization of the blood-brain barrier during and after stroke can lead to less adverse outcome. For elucidation of underlying mechanisms and development of novel therapeutic strategies validated in vitro disease models of the blood-brain barrier could be very helpful. To mimic in vitro stroke conditions we have established a blood-brain barrier in vitro model based on mouse cell line cerebEND and applied oxygen/glucose deprivation (OGD). The role of astrocytes in this disease model was investigated by using cell line C6. Transwell studies pointed out that addition of astrocytes during OGD increased the barrier damage significantly in comparison to the endothelial monoculture shown by changes of transendothelial electrical resistance as well as fluorescein permeability data. Analysis on mRNA and protein levels by qPCR, western blotting and immunofluorescence microscopy of tight junction molecules claudin-3,-5,-12, occludin and ZO-1 revealed that their regulation and localisation is associated with the functional barrier breakdown. Furthermore, soluble factors of astrocytes, OGD and their combination were able to induce changes of functionality and expression of ABC-transporters Abcb1a (P-gp), Abcg2 (bcrp), and Abcc4 (mrp4). Moreover, the expression of proteases (matrixmetalloproteinases MMP-2, MMP-3, MMP-9, and t-PA) as well as of their endogenous inhibitors (TIMP-1, TIMP-3, PAI-1) was altered by astrocyte factors and OGD which resulted in significant changes of total MMP and t-PA activity. Morphological rearrangements induced by OGD and treatment with astrocyte factors were confirmed at a nanometer scale using atomic force microscopy. In conclusion, astrocytes play a major role in blood-brain barrier breakdown during OGD in vitro.
KW  - oxygen/glucose deprivation
KW  - ischemia
KW  - traumatic brain injury
KW  - cerebEND
KW  - C6
KW  - stroke
KW  - in vitro
KW  - blood-brain barrier
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118297
SN  - 1662-5102
VL  - 8
ER  - 
TY  - JOUR
A1  - Neuhaus, Winfried
A1  - Schlundt, Marian
A1  - Fehrholz, Markus
A1  - Ehrke, Alexander
A1  - Kunzmann, Steffen
A1  - Liebner, Stefan
A1  - Speer, Christian P.
A1  - Förster, Carola Y.
T1  - Multiple antenatal dexamethasone treatment alters brain vessel differentiation in newborn mouse pups
JF  - PLoS ONE
N2  - Antenatal steroid treatment decreases morbidity and mortality in premature infants through the maturation of lung tissue, which enables sufficient breathing performance. However, clinical and animal studies have shown that repeated doses of glucocorticoids such as dexamethasone and betamethasone lead to long-term adverse effects on brain development. Therefore, we established a mouse model for antenatal dexamethasone treatment to investigate the effects of dexamethasone on brain vessel differentiation towards the blood-brain barrier (BBB) phenotype, focusing on molecular marker analysis. The major findings were that in total brains on postnatal day (PN) 4 triple antenatal dexamethasone treatment significantly downregulated the tight junction protein claudin-5, the endothelial marker Pecam-1/CD31, the glucocorticoid receptor, the NR1 subunit of the N-methyl-D-aspartate receptor, and Abc transporters (Abcb1a, Abcg2 Abcc4). Less pronounced effects were found after single antenatal dexamethasone treatment and in PN10 samples. Comparisons of total brain samples with isolated brain endothelial cells together with the stainings for Pecam-1/CD31 and claudin-5 led to the assumption that the morphology of brain vessels is affected by antenatal dexamethasone treatment at PN4. On the mRNA level markers for angiogenesis, the sonic hedgehog and the Wnt pathway were downregulated in PN4 samples, suggesting fundamental changes in brain vascularization and/or differentiation. In conclusion, we provided a first comprehensive molecular basis for the adverse effects of multiple antenatal dexamethasone treatment on brain vessel differentiation.
KW  - preterm birth
KW  - fetal lung
KW  - corticosteroids
KW  - glucocorticoids
KW  - exposure
KW  - endothelial cells
KW  - in vitro
KW  - barrier
KW  - expression
KW  - rat
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148268
VL  - 10
IS  - 8
ER  -