A single nuclear transcriptomic characterization of mechanisms responsible for impaired angiogenesis and blood-brain barrier function in Alzheimer’s disease
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE252921 | GEO | 2024/01/20
REPOSITORIES: GEO
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Project description:The receptor tyrosine kinase Mer (gene name Mertk) acts in vascular endothelial cells (ECs) to tighten the blood-brain barrier (BBB) subsequent to viral infection. Correspondingly, we found that Mer regulates the expression and activity of a large cohort of cytoskeletal and BBB proteins, together with endothelial nitric oxide synthase, in brain ECs. We further found that Mer controls the expression of multiple angiogenic genes, and that EC-specific Mertk gene inactivation results in perturbed vascular sprouting and a compromised BBB after induced photothrombotic stroke. Unexpectedly, stroke lesions in the brain were also markedly reduced in the absence of EC Mer, which was linked to reduced plasma expression of fibrinogen, prothrombin, and other effectors of blood coagulation. Together, these results demonstrate that Mer is a central regulator of angiogenesis, BBB integrity, and blood coagulation in the mature vasculature. They may also account for disease severity following infection with the coronavirus SARS-CoV-2.
2023-02-23 | MSV000091355 | MassIVE
Project description:With advances in single-cell genomics, molecular signatures of cells comprising the brain vasculature are revealed in unprecedented detail, yet the ageing-associated cell subtype transcriptomic changes which may contribute to neurovascular dysfunction in neurodegenerative diseases remain elusive. Here, we performed single-cell transcriptomic profiling of brain endothelial cells (EC) in young adult and aged mice to characterize their ageing-associated genome-wide expression changes. We identified zonation-dependent transcriptomic changes in aged brain EC subtypes, with capillary ECs exhibiting the most transcriptomic alterations. Pathway enrichment analysis revealed altered immune/cytokine signaling in ECs of all vascular segments, while functional changes impacting the blood-brain barrier (BBB) and glucose/energy metabolism were most prominently implicated in ECs of the capillary bed – the primary site where ECs and other neurovascular unit (NVU) cell types closely interact and coordinate to regulate BBB and cerebral blood flow in health and diseased conditions. Furthermore, an overrepresentation of Alzheimer’s disease (AD)-associated genes identified from GWAS studies was evident among the human orthologs of differentially expressed genes of aged capillary ECs but not other EC subtypes. Importantly, for numerous EC-enriched differentially expressed genes with important functional roles at the BBB and/or association with AD, we found concordant expression changes in human aged or AD brains. Finally, we demonstrated that treatment with exenatide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, strongly reverses transcriptomic changes in ECs and largely reduces BBB leakage in the aged brain. Thus, our study revealed novel vascular ageing-associations of AD in the brain capillary endothelium, and provides insights into detailed transcriptomic alterations underlying brain EC ageing that are complex with subtype specificity yet amenable to pharmacological interventions.
2020-03-30 | GSE147693 | GEO
Project description:The receptor tyrosine kinase Mer (gene name Mertk) acts in vascular endothelial cells (ECs) to tighten the blood-brain barrier (BBB) subsequent to viral infection. Correspondingly, we found that Mer regulates the expression and activity of a large cohort of cytoskeletal and BBB proteins, together with endothelial nitric oxide synthase, in brain ECs. We further found that Mer controls the expression of multiple angiogenic genes, and that EC-specific Mertk gene inactivation results in perturbed vascular sprouting and a compromised BBB after induced photothrombotic stroke. Unexpectedly, stroke lesions in the brain were also markedly reduced in the absence of EC Mer, which was linked to reduced plasma expression of fibrinogen, prothrombin, and other effectors of blood coagulation. Together, these results demonstrate that Mer is a central regulator of angiogenesis, BBB integrity, and blood coagulation in the mature vasculature. They may also account for disease severity following infection with the coronavirus SARS-CoV-2.
2023-08-24 | GSE225474 | GEO
Project description:The blood-brain barrier (BBB) plays important roles in brain tumor pathogenesis and treatment response, yet our understanding of its function and heterogeneity within or across brain tumor types remains poorly characterized. Here we analyze the neurovascular unit (NVU) of pediatric high-grade glioma (pHGG) and diffuse midline glioma (DMG) using patient derived xenografts and natively forming glioma mouse models. We show tumor-associated vascular differences between these glioma subtypes, and parallels between PDX and mouse model systems, with DMG models maintaining a more normal vascular architecture, BBB function and endothelial transcriptional program relative to pHGG models. Unlike prior work in angiogenic brain tumors, we find that expression of secreted Wnt antagonists do not alter the tumor-associated vascular phenotype in DMG tumor models. Together, these findings highlight vascular heterogeneity between pHGG and DMG and differences in their response to alterations in developmental BBB signals that may participate in driving these pathological differences.
2021-09-01 | GSE179372 | GEO
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2024-02-22 | GSE251849 | GEO
Project description:Endothelial cells (ECs) in cerebral vessels are considered the primary targets in acute hemorrhagic brain injuries. EC dysfunction can aggravate neuronal injuries by causing secondary inflammatory responses and blood-brain barrier (BBB) disruption. ECs comprising the BBB are known to have a higher mitochondrial volume compared with peripheral ECs. In previous study, we reported Tek-CRIF1-knockout (KO) mice, with EC-specific deletion of the mitochondrial OxPhos-related gene, Crif1, also known as Gadd45gip1 (encoding GADD45G-interacting protein 1), display profound BBB defects accompanied by reduced expression of junctional proteins in ECs. To identify signaling pathways involved in linking EC-specific mitochondrial dysfunction and BBB disruption, we first performed RNA sequencing using isolated cerebral vessels from Tek-CRIF1 mice. This transcriptome analyses of the Tek-CRIF1-KO mouse revealed significant changes in some signaling, a pathway intimately involved in BBB maintenance.
2022-08-31 | GSE207106 | GEO
Project description:Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare, genetic premature aging disorder associated with severe atherosclerosis, often resulting in fatal heart attacks and strokes. Progerin, the mutant protein in HGPS, also is expressed in healthy individuals and may play a role in the development of atherosclerosis during physiologic aging. Here, we provide evidence for a primary involvement of vascular endothelium in the pathogenesis of accelerated atherosclerosis in HGPS. Expression of progerin in cultured human endothelial cells induces a dysfunctional phenotype, manifested by activation of multiple pro-inflammatory, pro-atherogenic genes. In particular, our data implicate endothelial-derived interleukin-1 (IL-1) as a key mediator of a pro-inflammatory vascular phenotype. Endothelial activation also is detectable in a mouse model of HGPS, and appears to be conveyed to neighboring vascular cells via autocrine and paracrine signaling. These new mechanistic insights into the vascular pathobiology of HGPS may have therapeutic implications for this disease. Genome-wide transcriptional profiling was carried out to assess functional phenotypic changes in endothelial cells (EC) as a result of progerin expression. Cultured EC were infected with an adenovirus expressing progerin (Ad-Progerin), and as a control, an adenovirus that did not express any construct (Ad-Null). Experiments were preformed with three different EC cultures.
2010-12-02 | E-GEOD-19270 | biostudies-arrayexpress
Project description:PDGF-BB:PDGFRβ signalling in brain pericytes is critical to the development, maintenance and function of a healthy blood-brain barrier (BBB). Furthermore, BBB impairment and pericyte loss in Alzheimer’s disease (AD) is well documented. We used tissue microarrays from control and AD brains to determine if PDGF-BB:PDGFRβ signalling components were altered in AD, and found that there was a reduction in vascular expression of PDGFB. We hypothesised that reduced PDGF-BB:PDGFRβ signalling in pericytes may have an impact on functions related to the BBB. We therefore tested the effects of PDGF-BB on primary human brain pericytes in vitro to define important signalling pathways and outcomes related to BBB function. Pericytes demonstrate a biphasic response to PDGF-BB, predominantly dependent on Akt and ERK. We determined that the actions of PDGF-BB are on-target at PDGFRβ, leading to internalisation and degradation of PDGFRβ. Using pharmacological inhibitors, we dissected distinct aspects of the PDGF-BB response that are controlled by ERK and Akt pathways. PDGF-BB promotes the proliferation of pericytes and protection from toxic stimuli through ERK signalling. In contrast, PDGF-BB:PDGFRβ signalling through Akt and NF-κB augments pericyte-derived inflammatory secretions. It may therefore be possible to supplement PDGF-BB or small molecule agonists to stabilise the cerebrovasculature in AD.
2021-11-30 | GSE189712 | 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:The blood-brain barrier (BBB) dynamically controls and maintains a precisely balanced brain microenvironment necessary for reliable functioning. It is made up of highly specialized endothelial cells (ECs) in the lining of the vascular wall. These ECs are surrounded by the basal lamina, astrocytic perivascular endfeet, pericytes, microglia and neuronal processes that have been shown to contribute to barrier function1. In essence, the brain endothelium limits both transcellular and paracellular passage of cells and molecules into the central nervous system (CNS). Transcellular passage of hydrophilic molecules is limited due to a low rate of transcytotic vesicles, an extremely low pinocytotic activity, expression of active efflux transporters, and high metabolic activity. Paracellular diffusion of hydrophilic molecules and trafficking of immune cells is restricted by a network of tight junctions (TJs)2-5. Due to these characteristics, the BBB is able to protect the CNS from sudden changes in blood composition and uncontrolled influx of immune cells. In a large number of neuro-inflammatory diseases, an impaired function and an opening of the BBB are observed. In diseases of the CNS like multiple sclerosis or stroke or after brain trauma, the BBB becomes inflamed (mediated by for example reactive oxygen species (ROS) and hypoxia) and its function severely impaired which gives rise to enhanced cellular infiltration, thus contributing to tissue damage and neurological deficits. Due to the specialized nature of brain ECs, transmigration of leukocytes through cerebrovascular endothelium is likely to differ from that in other vascular beds. Generally, the transmigration process is closely controlled by the interaction of leukocytes with the endothelial surface followed by low velocity rolling, arrest, firm adhesion, and finally transmigration. For the diapedesis of immune cells across the cerebral vasculature a re-arrangement of the cytoskeleton and opening of the TJ complexes is required to allow cells to pass into the sub endothelial space. In the initial step of the adhesive cascade leukocytes adhere to the endothelium with low affinity. This adhesion is mediated by several members of the selectin family and their corresponding ligands. Despite the low affinity of these interactions, resulting contact of leukocytes with the endothelium leads to further activation of both cell types and finally transmigration of the leukocytes through the BBB6,7. The glycosylation of endothelial cells of different vascular bed origins To date it is unknown which specific carbohydrate structures on the BBB endothelium mediate leukocyte capture and rolling, and whether these structures are differentially expressed onto inflamed brain EC compared to normal brain ECs and vascular beds of other organs. Initial studies using qPCR and FACS analysis within our group reveal that brain endothelial cells have a different profile in their glycosylation-related genes compared to microvascular ECs upon inflammation, which may result in a different glycosylation profile of adhesive structures and may underlie rolling, adhesion and diapedesis of leukocytes. In this project we wish to identify specific, glycosylated structures on brain endothelial cells that mediate capture, rolling and diapedesis of leukocytes in the brain. To investigate the expression of glycosyltransferases in dendritic cells and the changes in expression associated with maturation. RNA preparations from stimulated and non-stimulated hcMEC/D3 (human brain endothelial cells line) and FMVEC (human promary microvascular endothelial cells isolated from foreskins) were sent to both Microarray Core (E) and Core(C). The RNA was put on an RNeasy Column, amplified, labeled, and hybridized to the Glycov3 microarrays. Data was sent to Dr. van Kooyk's lab for analysis.
2011-06-14 | E-GEOD-29932 | biostudies-arrayexpress