Project description:The CCM endothelium is hypersensitive to angiogenesis and can induce a hypoxic program associated with changes in angiogenesis, inflammation, and endothelial-cell metabolism under normoxic conditions. However, the role of active drivers of angiogenesis as CCM disease modifiers in human disease remains unclear. To examine if hypoxia, a driver of angiogenesis, may contribute to CCM exacerbation, we performed bulk RNA-seq of brain tissue from P50 Pdcd10BECKO mice under normoxia and hypoxia. P50 Pdcd10fl/fl littermate controls under normoxia and hypoxia were used as controls.
Project description:The CCM endothelium is hypersensitive to angiogenesis and can induce a hypoxic program associated with changes in angiogenesis, inflammation, and endothelial-cell metabolism under normoxic conditions. However, the role of active drivers of angiogenesis as CCM disease modifiers in human disease remains unclear. To assess whether CCM reactive astrocytes with neuroinflammatory capacity respond to hypoxia-induced CCM exacerbation, we employed the astrocyte-specific (Aldh1l1-EGFP/Rpl10a) Translational Ribosome Affinity Purification (TRAP) system in combination with a CCM mouse model (Pdcd10BECKO;Aldh1l1-EGFP/Rpl10a). TRAP protocol was performed using Slco1c1-iCreERT2;Pdcd10fl/fl;Aldh1l1-EGFP/Rpl10a mice to isolate ribosomes from astrocytes as previously described. Astrocyte-TRAP mRNAs were from cerebral tissue of mice age P50 exposed to hypoxia or normoxia conditions.
Project description:Cerebral cavernous malformation (CCM) immunothrombosis is the connection between immune cells, platelet activation, coagulation cascades and astrocyte-CCM endothelium interaction, and its excessive activation may contribute to neurological disabilities in CCM disease. We characterized the spatial organization of CCM immunothrombosis observed in Pdcd10BECKObrains under normoxic conditions using the murine 10X Genomics Visium Spatial Gene Expression platform.
Project description:Neuroinflammation plays a role in the progression of several neurodegenerative disorders. We used a lipolysaccharide (LPS) model of neuroinflammation to characterize the gene expression changes underlying the inflammatory and behavioral effects of neuroinflammation. A single intracerebroventricular injection of LPS (5 ug) was administered into the lateral ventricle of mice and, 24 hours later, we examined gene expression in the cerebral cortex and hippocampus using microarray technology. Gene Ontology (GO) terms for inflammation and the ribosome were significantly enriched by LPS, whereas GO terms associated with learning and memory had decreased expression. We detected 224 changed transcripts in the cerebral cortex and 170 in the hippocampus. Expression of Egr1 (also known as Zif268) and Arc, two genes associated with learning and memory, was significantly lower in the cortex, but not hippocampus, of LPS-treated animals. Overall, altered expression of these genes may underlie some of the inflammatory and behavioral effects of neuroinflammation. Mice were given intracerebroventricular injections of saline vehicle (n = 4) or lipopolysaccharide (n = 4). Twenty-four hours later, we dissected the hippocampus and cerebral cortex and processed the tissue for microarray analysis. Gene expression changes observed in the microaray data were validated with quantitative real-time PCR.
Project description:Cerebral vascular malformations (CCM) are primarily found within brain, where they result in increased risk for stroke, seizures and focal neurological deficits. The unique feature of the brain vasculature is the blood-brain barrier (BBB) formed by the brain neurovascular unit, and recent studies suggest that loss of CCM genes causes disruptions of BBB integrity as the inciting event for the development of CCM. CCM lesion is proposed to be initially derived from a single clonal expansion of a subset of angiogenic venous capillary endothelial cells (ECs) and respective resident endothelial progenitor cells (EPCs). However, the critical signaling in the subclass of brain EC/EPC for the CCM lesion initiation and progression are unclear. Here we employed single-cell RNA-sequencing (scRNA-seq) analyses in early stages of the brain EC-specific Ccm3 deletion (Pdcd10BECKO) microvessels and identified a unique EPC cluster with high stem cell markers but low BBB-associated genes. mTORC1, but not mTORC2, is activated in mouse and human CCM lesions and EPCs. Mechanistic studies suggest that CCM3 suppresses Cav1/caveolae-mediated cellular trafficking and complex formation of the mTORC1 signaling proteins. Genetic deficiency of Raptor (mTORC1), but not of Rictor (mTORC2), prevents CCM lesion formation in the Pdcd10BECKO model. Importantly, mTORC1 pharmacological inhibitor Rapamycin ameliorate the CCM pathogenesis in the Pdcd10BECKO mice, by suppressing lesion-forming EPC expansion while enhancing BBB maturation. Our data suggest that CCM3 is critical for maintaining BBB integrity, and CCM3 loss-induced mTORC1 signaling in brain EPCs initiate the CCM pathogenesis.
Project description:WNT2 is important for placenta vascularization and acts as a pro-angiogenic factor for liver and other endothelial cells (ECs). WNT2 induction has been shown in many carcinomas and is associated with tumor progression. In colorectal cancer (CRC) WNT2 is selectively elevated in cancer associated fibroblasts (CAFs), leading to increased invasion and metastasis. However, if there is a role for WNT2 in colon cancer angiogenesis has not been addressed so far. Here, we demonstrate that WNT2 enhances EC migration and invasion, while it induces ß catenin dependent signaling in only a small subset of HUVECs. We show that siRNA-mediated knockdown of WNT2 in CAFs reduced the growth of vessel-like structures significantly in a co-culture assay, while the overexpression of WNT2 in skin fibroblasts otherwise being devoid of WNT2 led to increased angiogenesis in vitro. In a xenograft model, overexpression of WNT2 in HCT116 led to enhanced tumor volume and vessel density. Moreover, WNT2 expression correlates with vessel markers in human CRC. Secretome profiling of CAFs revealed that proteins related to angiogenesis and extracellular matrix (ECM) remodeling are regulated by WNT2. Thus, stroma-derived WNT2 positively affects angiogenesis in CRC by shifting the balance towards pro-angiogenic signals.