Histone Modification in Cerebral Arteriovenous Malformation
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ABSTRACT: Cerebral arteriovenous malformations (AVMs) are the most common vascular malformations worldwide and the leading cause of hemorrhagic strokes that result in crippling neurological deficits. Here, using newly generated mouse model, we discovered that genome-wide ocuppancy of H4K8ac and H3K27me3 decreased in mouse cerebral AVMs.
Project description:Cerebral cavernous malformations are vascular anomalies that can cause hemorrhagic stroke. Mutations in genes encoding Krit 1 (CCM1), OSM (CCM2), and PDCD10 (CCM3) proteins cause CCM. A loss in teh expression of any of these CCM proteins disrupts normal cerebral vessel development by disrupting the cytoskeleton and thereby inhibits endothelial tube ofrmation. Examination of cellular changes based on the loss of CCM gene expression may lead to the methods for early detection and prevention of CCM associated hemorrhagic stroke.
Project description:Arteriovenous malformations (AVMs) are characteristic of hereditary hemorrhagic telangiectasia (HHT). We used single cell RNA sequencing (scRNA-seq) to trace pulmonary EC lineages in mice with endothelial-specific deletion of Alk1 gene.
Project description:Arteriovenous malformations (AVMs) are characteristic of hereditary hemorrhagic telangiectasia (HHT). We used single cell RNA sequencing (scRNA-seq) to analyzed the pulmonary ECs in mice with endothelial-specific deletion of Alk1 gene.
Project description:To investigate the endothelial-mesenchymal transition in cerebral arteriovenous malformation. We performed gene expression profiling analysis using the data obtained from RNA-seq of CD31+CD45- brain cells in Cdh5cre;Mgpflox/flox mice with or without tamoxifen induction.
Project description:Lumen integrity in vascularization requires fully differentiated endothelial cells (ECs). Here, we report that endothelial-mesenchymal transitions (EndMTs) emerged in ECs of cerebral arteriovenous malformation (AVMs) and caused disruption of the lumen or lumen disorder. We show that excessive Sry-box 2 (Sox2) signaling was responsible for the EndMTs in cerebral AVMs. EC-specific suppression of Sox2 normalized endothelial differentiation and lumen formation, and improved the cerebral AVMs. Epigenetic studies showed that induction of Sox2 altered the cerebral-endothelial transcriptional landscape, and identified jumonji domain-containing protein 5 (JMJD5) as a direct target of Sox2. Sox2 interacted with JMJD5 to induce EndMTs in cerebral ECs. Furthermore, we utilized a high throughput system to identify the beta-adrenergic antagonist pronethalol as an inhibitor of Sox2 expression. Treatment with pronethalol stabilized endothelial differentiation and lumen formation, which limited the cerebral AVMs.
Project description:Hereditary hemorrhagic telangiectasia (HHT) is an inherited autosomal dominant disorder associated with mutations in the bone morphogenetic protein (BMP) pathway. Inherited heterozygous loss of function mutations and acquired loss of heterozygosity in either Alk1, Eng, or Smad4 lead to the development of arteriovenous malformations (AVMs), which trigger local vessel instability, hypoxia and vessel leakage or rupture. Current models assume common cellular pathomechanisms culminating in altered endothelial cell (EC) shape regulation, directional migration and proliferation control as a consequence of deficient BMP pathway signaling in ECs under the influence of blood-flow mediated shear stress. Here we report that loss of Alk1 or Smad4 surprisingly triggers very distinct endothelial phenotypes, signaling dynamics and transcriptional changes in ECs, both in vitro and in vivo. EC behavior in both in vivo and mosaic flow cultures illustrate that cells deficient in Smad4 effectively migrate against the direction of fluid shear, from veins to arteries, whereas cells lacking Alk1 fail to polarize and migrate against flow. Our data suggest that AVMs triggered by Smad4 mutations occur through hyperpruning of capillaries, thus precipitating flow in a single shunt, whereas AVMs caused by Alk1 mutation grow by cell accumulations close to the vein, as well as the persistence of a hyperdense plexus that drives nidus formation. We propose that the cellular pathomechanisms leading to AVM formation are not the same if the upstream BMP receptor Alk1, or the downstream common transcription factor Smad4 are mutated, raising the prospect for urgently needed, mechanism-based, therapeutic avenues that need to be tailored to correcting the specific pathomechanism.