The secreted neuronal signal Spock1 regulates the blood-brain barrier
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE230236 | GEO | 2023/05/01
REPOSITORIES: GEO
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Project description:The blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB. The brain microvascular fragments were isolated from mice with different genotypes, each represented by 3-4 biological replicates. Genotypes 1-2: Platelet derived growth factor-B (PDGF-B) retention-motif knockout (pdgfbret/ret) represent the pericyte-deficient situation, and the heterozygous mice (pdgfbret/+) are used as controls. Genotypes 3-4: Hypomorphic PDGF-B mutants that rescue pdgfb-/- null mice, in which a one copy of a conditionally silent human PDGF-B transgene targeted to the Rosa 26 locus (R26P) is turned on by endothelial-specific expression of Cre recombinase. In this data set these mice are named as Tie2Cre, R26P+/0, pdgfb-/- (representing the pericyte-deficient situation). Mice wt for pdgfb (pdgfb+/+) and carrying one silent copy of R26P (R26P+/0), are used as controls. Genotype 5: Adult Notch3+/+ wildtype (WT).
2010-10-21 | E-GEOD-15892 | biostudies-arrayexpress
Project description:Genetic variation in the population has an influence on the manifestation of monogenic as well as multifactorial disorders, with the underlying genetic contribution dependent on several interacting variants. Common laboratory mouse strains used for modelling human disease lack the genetic variability of the human population. Therefore, outcomes of rodent studies show limited correlation with human disease. The functionality of brain vasculature is an important modifier of brain diseases. Importantly, the restrictive interface between blood and brain – the blood-brain barrier (BBB) serves as a major obstacle for CNS drug delivery. Using genetically diverse mouse strains, we aimed to investigate the phenotypic and transcriptomic variation of the intact BBB in different inbred mouse strains.We investigated the heterogeneity of brain vasculature in recently wild-derived mouse strains (CAST/EiJ, WSB/EiJ, PWK/PhJ) and long-inbred mouse strains (129S1/SvImJ, A/J, C57BL/6J, DBA/2J, NOD/ShiLtJ) using different phenotypic arms. We used immunohistochemistry and confocal laser microscopy followed by quantitative image analysis to determine vascular density and pericyte coverage in two brain regions – cortex and hippocampus. Using a low molecular weight fluorescence tracer, sodium fluorescein and spectrophotometry analysis, we assessed BBB permeability in young and aged mice of selected strains. For further phenotypic characterization of endothelial cells in inbred mouse strains, we performed bulk RNA sequencing of sorted endothelial cells isolated from cortex and hippocampus. We did not detect differences in cortical and hippocampal vessel density and pericyte coverage among all the investigated strains. The staining patterns of endothelial arteriovenous zonation markers were similar in different strains. BBB permeability to a small fluorescent tracer, sodium fluorescein, was also similar in different strains. Transcriptomic analysis of endothelial cells revealed that sex of the animal was a major determinant of gene expression differences. In addition, the expression level of several genes implicated in endothelial function and BBB biology differed between wild-derived and long-inbred mouse strains. Our analysis shows that although there were no major differences in parenchymal vascular morphology and BBB permeability between investigated mouse strains or sexes, transcriptomic differences of brain endothelial cells point to variation in gene expression of the intact BBB. These baseline variances might be confounding factors in pathological conditions that may lead to a differential functional outcome dependent on the sex or genetic polymorphism.
2021-08-03 | GSE173793 | GEO
Project description:The blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.
2010-10-21 | GSE15892 | GEO
Project description:Alzheimer’s disease (AD) is an age-related disease, with loss of integrity of the blood-brain barrier (BBB) being an early feature. Cellular senescence is one of the reported nine hallmarks of aging. Here we show for the first time the presence of senescent cells in the vasculature in AD patients and mouse models of AD. Senescent endothelial cells and pericytes are present in APP/PS1 transgenic mice but not in wild-type littermates at the time of amyloid deposition. In vitro, senescent endothelial cells display altered VE-cadherin expression and loss of cell junction formation and increased permeability. Consistent with this, senescent endothelial cells in APP/PS1 mice are present at areas of vascular leak that have decreased claudin-5 and VE-cadherin expression confirming BBB breakdown. Further, single cell sequencing of endothelial cells from APP/PS1 transgenic mice confirms that adhesion molecule pathways are among the most highly altered pathways in these cells. At the pre-plaque stage the vasculature shows significant signs of breakdown, with a general loss of VE-cadherin, leakage within the microcirculation, and obvious pericyte perturbation. Although senescent vascular cells were not directly observed at sites of vascular leak, senescent cells were close to the leak area. Thus, we would suggest in AD there is a progressive induction of senescence in constituents of the neurovascular unit contributing to an increasing loss of vascular integrity. Targeting the vasculature early in AD, either with senolytics or with drugs that improve the integrity of the BBB maybe valid therapeutic strategies.
2023-12-07 | GSE243576 | GEO
Project description:Brain tumors, either primary or secondary, have limited therapeutic options despite advances in understanding tumor driving gene mutations and heterogeneity within tumor cells. The cellular and molecular composition of brain tumor stroma, an important modifier of tumor growth, has been less investigated and understood. Especially, studies focusing on brain tumor blood vessels are rare, yet, the brain endothelium and the blood-brain barrier (BBB) are the major obstacle for efficient drug delivery. In this study we have employed the RNA sequencing approach to get insights into transcriptional alterations of endothelial cells isolated from primary and secondary brain tumors. We used an immunoprecipitation approach to enrich for endothelial cells of normal brain, glioblastoma (GBM) and adenocarcinoma brain metastasis (BM). Analysis of the endothelial transcriptome showed that both the GBM and the BM vasculature showed deregulation of genes implicated in cell proliferation, angiogenesis, deposition of extracellular matrix (ECM), and deregulation of genes defining the BBB dysfunction module. We describe alterations in the BBB genes in the GBM and BM vasculature and identify proteins that could be exploited for developing drug delivery platforms into primary and secondary brain tumors. In addition, we identify deregulated expression of genes defining vessel-associated fibroblasts in the GBM tissue, highlighting that the cellular composition of the brain tumor stroma deserves further investigation.
2021-02-10 | GSE159851 | GEO
Project description:Derangements of the blood-brain barrier (BBB) or blood-retinal barrier (BRB) occur in disorders ranging from stroke, cancer, diabetic retinopathy, and Alzheimer's disease. The Norrin/FZD4/TSPAN12 pathway activates WNT/-catenin signaling, which is essential for BBB and BRB function. However, systemic pharmacologic FZD4 stimulation is hindered by obligate palmitoylation and insolubility of native WNTs and suboptimal properties of the FZD4-selective ligand Norrin. Here, we developed L6-F4-2, a non-lipidated, FZD4-specific surrogate with significantly improved sub-picomolar affinity versus native Norrin. In Norrin knockout (NdpKO) mice, L6-F4-2 not only potently reversed neonatal retinal angiogenesis deficits, but also restored BRB and BBB function. In adult C57Bl/6J mice, post-stroke systemic delivery of L6-F4-2 strongly reduced BBB permeability, infarction, and edema, while improving neurologic score and capillary pericyte coverage. Our findings reveal systemic efficacy of a bioengineered FZD4-selective WNT surrogate during ischemic BBB dysfunction, with general applicability to adult CNS disorders characterized by an aberrant blood-brain barrier.
2023-01-31 | GSE223628 | GEO
Project description:Derangements of the blood-brain barrier (BBB) or blood-retinal barrier (BRB) occur in disorders ranging from stroke, cancer, diabetic retinopathy, and Alzheimer's disease. The Norrin/FZD4/TSPAN12 pathway activates WNT/-catenin signaling, which is essential for BBB and BRB function. However, systemic pharmacologic FZD4 stimulation is hindered by obligate palmitoylation and insolubility of native WNTs and suboptimal properties of the FZD4-selective ligand Norrin. Here, we developed L6-F4-2, a non-lipidated, FZD4-specific surrogate with significantly improved sub-picomolar affinity versus native Norrin. In Norrin knockout (NdpKO) mice, L6-F4-2 not only potently reversed neonatal retinal angiogenesis deficits, but also restored BRB and BBB function. In adult C57Bl/6J mice, post-stroke systemic delivery of L6-F4-2 strongly reduced BBB permeability, infarction, and edema, while improving neurologic score and capillary pericyte coverage. Our findings reveal systemic efficacy of a bioengineered FZD4-selective WNT surrogate during ischemic BBB dysfunction, with general applicability to adult CNS disorders characterized by an aberrant blood-brain barrier.
2023-01-31 | GSE223498 | GEO
Project description:The precise regulation of blood-brain-barrier (BBB) permeability for immune cells and blood-borne substances is essential to maintain brain homeostasis. Sphingosine-1-phosphate (S1P), a lipid signaling molecule enriched in plasma, is known to affect BBB permeability. Previous studies focussed on endothelial S1P receptors 1 and 2, reporting a barrier-protective effect of S1P1 and a barrier-disruptive effect of S1P2. Here we present novel data characterizing the expression, localization and function of the hitherto exclusively immunce cell-associated S1P receptor 4 (S1P4) on primary brain microvascular endothelial cells (BMECs). We detected a robust expression of S1P4 in homeostatic BMECs and pinpointed its localization to abluminal endothelial membranes by electron microscopy. Basolateral S1P treatment of BMECs led to increased permeability in vitro associated with S1P4 downregulation. Likewise, downregulation of S1P4 was observed in mouse brain microvessels after stroke, a neurological disease associated with BBB impairment. RNA sequencing analysis of BMECs suggested involvement of S1P4 in endothelial homeostasis, apicobasal polarity and barrier function. Using siRNA, pharmacological agonists and antagonists of S1P4 both in vitro and in vivo, we demonstrate a barrier-protective function of S1P4. We therefore suggest S1P4 as a novel target regulating BBB permeability and propose its therapeutic targeting in CNS diseases associated with BBB dysfunction.
2021-10-04 | GSE163561 | GEO
Project description:The highly negatively charged endothelial surface glycocalyx (ESG) functions as mechano-sensor detecting shear forces generated by the blood flow on the luminal side of brain endothelial cells (ECs) and contributes to the physical barrier of the blood-brain barrier (BBB). Despite the importance of ESG in the regulation of BBB permeability in physiological conditions and in diseases, this is an underresearched area. Microfluidic lab-on-a-chip (LOC) devices allow the study of BBB properties in dynamic conditions. We studied a BBB model, human endothelial cells derived from hematopoetic stem cells in co-culture with brain pericytes, in an LOC device to understand the role of fluid flow in the regulation of ESG-related genes and surface charge. The MACE gene sequencing study showed differentially expressed core protein genes of the ESG after fluid flow, as well as enriched pathways for the extracellular matrix molecules. We observed increased barrier properties, a higher intensity glycocalyx staining and a more negative surface charge of human brain ECs in dynamic conditions. Our study is the first to provide data on ESG of human ECs in an LOC device under dynamic conditions and confirm the importance of fluid flow for BBB culture models.
2021-09-01 | GSE155671 | GEO
Project description:Rationale. The microvasculature of the central nervous system includes the blood-brain barrier (BBB), which regulates the permeability to nutrients and restricts the passage of toxic agents and inflammatory cells. Canonical Wnt/b-catenin signaling is responsible for the early phases of brain vascularization and blood-brain barrier differentiation. However, this signal declines after birth and other signaling pathways able to maintain barrier integrity at postnatal stage are still unknown. Objective. Sox17 constitutes a major downstream target of Wnt/b-catenin in endothelial cells and regulates arterial differentiation. In the present paper, we asked whether Sox17 may act downstream of Wnt/b-catenin in inducing BBB differentiation and maintenance. Methods and Results. Using reporter mice and nuclear staining of Sox17 and b-catenin, we report that while b-catenin signaling declines after birth, Sox17 activation increases and remains high in the adult. Endothelial-specific inactivation of Sox17 leads to increase of permeability of the brain microcirculation. The severity of this effect depends on the degree of BBB maturation: it is strong in the embryo, and progressively declines after birth. In search of Sox17 mechanism of action, RNA-Seq analysis of gene expression of brain endothelial cells has identified members of the Wnt/b-catenin signaling pathway as downstream targets of Sox17. Consistently, we found that Sox17 is a positive inducer of Wnt/b-catenin signaling and it acts in concert with this pathway to induce and maintain BBB properties. In vivo, inhibition of the b-catenin destruction complex or expression of a degradation-resistant b-catenin mutant, prevent the increase in permeability and retina vascular malformations observed in the absence of Sox17. Conclusions. Our data highlight a novel role for Sox17 in the induction and maintenance of the BBB and they underline the strict reciprocal tuning of this transcription factor and Wnt/b-catenin pathway. Modulation of Sox17 activity may be relevant to control BBB permeability in pathological conditions.
2019-02-12 | GSE122564 | GEO