Regulation of brain endothelial cell physiology by the TAM receptor tyrosine kinase Mer
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE225474 | GEO | 2023/08/24
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: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:To identify in CNS endothelial cell (EC) the gene cohorts that participate in blood brain barrier (BBB) formation versus maintenance. We investigated mechanisms behind the reduced Wnt/β-catenin signaling observed in adult CNS ECs We also investigated whether the adult endothelial cells can re express the EC gene cohorts required for the BBB formation.
2022-11-03 | GSE214923 | GEO
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 blood-brain barrier (BBB) is primarily manifested by a variety of physiological properties of brain endothelial cells (ECs), but the molecular foundation for these properties remains incompletely clear. Here, we generate a comprehensive molecular atlas of adult brain ECs using acutely purified mouse ECs and integrated multi-omics. Using RNA-seq and proteomics, we identify the transcripts and proteins selectively enriched in brain ECs and demonstrate that they are partially correlated. Using single-cell RNA-seq, we dissect the molecular basis of functional heterogeneity of brain ECs. Using integrative epigenomics and transcriptomics, we determine that TCF/LEF, SOX, and ETS families are top-ranked transcription factors regulating the BBB. We then validate the identified brain EC-enriched proteins and transcription factors in normal mouse and human brain tissue, and assess their expression changes in mice with Alzheimer’s disease. Overall, we present a valuable resource with broad implications for the BBB regulation and treatment of neurological disorders.
2023-10-31 | GSE185642 | GEO
Project description:Vascular endothelial cell (EC) function depends on appropriate organ-specific molecular and cellular specializations. To explore genomic mechanisms that control this specialization, we have analyzed and compared the transcriptome, accessible chromatin, and DNA methylome landscapes from mouse brain, liver, lung, and kidney ECs. Analysis of transcription factor (TF) motifs at candidate cis-regulatory elements together with TF gene expression reveals both shared and organ-specific EC TFs. In the embryo, only those ECs that are adjacent to or within the developing CNS exhibit canonical Wnt signaling, which correlates precisely with blood-brain barrier (BBB) differentiation and Zic3 expression. In acutely cultured brain ECs, the rapid loss of BBB markers is closely correlated with down-regulation of canonical Wnt signaling. In the early postnatal brain, single cell RNA-seq of purified ECs reveals close relationships between veins and mitotic cells and between arteries and tip cells, and a division of capillary ECs into vein-like and artery-like classes.
2018-09-06 | GSE111839 | GEO
Project description:The blood-brain barier (BBB) function is impaired in several neurological diseases such as stroke. To better study the BBB dysfunction in stroke and to identify novel therapeutic targets, a detailed analysis of the neurovascular unit (NVU) cells that together regulate the BBB function is needed. To this end, we isolated the NVU cells EC, PC, AC, MG post stroke in mice using our newly developed SGD (Spitzer, Guérit, Devraj) method from the same starting material followed by RNA sequencing. Cells were isolated from both healthy appearing contralateral hemisphere and ipsilateral stroke hemisphere post tMCAO (1h occlusion, 23h repurfusion) using the SGD method. Each sample comprised 6 biological replicates with each replicate pooled from 3-4 male C57BL6 adult mouse brains either from contralateral or ipsilateral hemisphere post stroke. Only mice with neurological scores (mNSS) of atleast 8 were included for the NVU cell isolation. Our data showed regulation of several genes post stroke in each of the cell types analyzed with novel candidates that were co-regulated in the NVU cell types. As the blood-brain barrier (BBB) is co-regulated by several NVU cell types, we propose targeting the candidates co-regulated in multiple NVU cell-ytpes for novel and effective therapeutic options in stroke.
2022-07-20 | GSE163752 | GEO
Project description:Endothelial cells (ECs) are constantly submitted in vivo to hemodynamical forces derived from the blood circulation, including shear stress (SS). EC are able to detect SS and consequently adapt their phenotype, thus affecting many endothelial functions. If a plethora of shear stress-regulated molecular networks have been described in peripheral EC, less is known about the molecular responses of microvascular brain ECs which constitute the blood-brain barrier (BBB). In this work, we investigated the response of human cerebral microvascular ECs to laminar physiological shear stress using the well characterized hCMEC/D3 cell line. Interestingly, we showed that hCMEC/D3 cells responded to shear stress by aligning perpendicularly to the flow direction, contrary to peripheral endothelial cells which aligned in the flow direction. Whole proteomic profiles were compared between hCMEC/D3 cells cultured either in static condition or under 5 or 10 dyn.cm-2 SS for three days. 3592 proteins were identified and expression levels were significantly affected for 3% of them upon both SS conditions. Pathway analyses were performed which revealed that most proteins overexpressed by SS refer to the antioxidant defense, probably mediated by activation of the NRF2 transcriptional factor. Regarding down-regulated proteins, most of them participate to the pro-inflammatory response, cell motility and proliferation. These findings confirm the induction of EC quiescence by laminar physiological SS and reveal a strong neuroprotective effect of SS on hCMEC/D3 cells, suggesting a similar effect on the BBB. Our results also showed that SS did not significantly increase expression levels nor did it affect the localization of junctional proteins or the functional activity of several ABC transporters (P-glycoprotein and MRPs). This work provides new insights on the response of microvascular brain EC to SS and on the importance of SS for optimizing in vitro BBB models.
2022-08-12 | PXD030493 | Pride
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
Project description:The blood brain barrier (BBB) protects the central nervous system from toxins and pathogens in the blood by regulating permeation of molecules through the barrier interface. In vitro BBB models described to date reproduce some aspects of BBB functionality, but also suffer from incomplete phenotypic expression of brain endothelial traits, difficulty in reproducibility and fabrication, or overall cost. To address these limitations, we describe a three-dimensional (3D) BBB model based on a hybrid paper/nanofiber scaffold. The cell culture platform utilizes lens paper as a framework to accommodate 3D culture of astrocytes. An electrospun nanofiber layer is coated onto one face of the paper to mimic the basement membrane and support growth of an organized two-dimensional layer of endothelial cells (ECs). Human induced pluripotent stem cell-derived ECs and astrocytes are co-cultured to develop a human BBB model. Morphological and spatial organization of model are validated with confocal microscopy. Measurements of transendothelial resistance and permeability demonstrate the BBB model develops a high-quality barrier and responds to hyperosmolar treatments. RNA-sequencing shows introduction of astrocytes both regulates EC tight junction proteins and improves endothelial phenotypes related to vasculogenesis. This model shows promise as a model platform for future in vitro studies of the BBB.
2021-11-01 | GSE181332 | GEO