Context dependent molecular cues shape the formation of the cerebral vascular network and the function of the blood-brain barrier (BBB). The Wnt/ß-catenin pathway is orchestrating CNS vascular development, but downstream mediators have not been characterized. Here we generated an endothelial cell-specific R26-Axin1 overexpression (AOE) mouse model to inhibit Wnt/ß-catenin signaling. In AOE mice we discovered that blockade of Wnt/ß-catenin pathway leads to premature regression and remodeling without compromising BBB integrity. Importantly, by comparing transcriptomes of endothelial cells from wildtype and AOE mice, we identified ADAMTSL2 as a novel Wnt/ß-catenin-induced, secreted factor, important for stabilizing the BBB during development. Zebrafish loss-of-function and gain-of-function models, further demonstrated that ADAMTSL2 is crucial for normal vascular development and could rescue vascular phenotypes in AOE zebrafish brains. In conclusion, the studies presented here reveal a hitherto unrecognized role of ADAMTSL2 as an endothelial cell-specific mediator of Wnt/ß-catenin signaling during CNS vascular development and BBB-formation. Overall design: Examination of expression changes in mouse brain endothelial cells when overexpressing Axin1
Disruption of the Extracellular Matrix Progressively Impairs Central Nervous System Vascular Maturation Downstream of β-Catenin Signaling.
No sample metadata fields
View SamplesPatients with systemic lupus erythematosus (SLE) have a markedly increased risk to develop cardiovascular disease, and traditional cardiovascular risk factors fail to account for this increased risk. We used microarray to probe the platelet transcriptome in individuals with SLE and healthy controls, and the gene and protein expression of a subset of differentially expressed genes was further investigated and correlated to platelet activation status. Real-time PCR was used to confirm a type I interferon (IFN) gene signature in patients with SLE, and the IFN-regulated proteins PRKRA, IFITM1 and CD69 (p<0.0001) were found to be up-regulated in platelets from SLE patients as compared to healthy volunteers. Notably, patients with a history of vascular disease had increased expression of type I IFN-regulated proteins as well as more activated platelets as compared with patients without vascular disease. We suggest that interferogenic immune complexes stimulate production of IFN which up-regulates the megakaryocytic type I IFN-regulated genes and proteins. This could affect platelet activation and contribute to development of vascular disease in SLE. In addition, platelets with type I IFN signature could be a novel marker for vascular disease in SLE.
Platelet transcriptional profile and protein expression in patients with systemic lupus erythematosus: up-regulation of the type I interferon system is strongly associated with vascular disease.
Sex, Age, Specimen part, Disease
View SamplesThe importance of the role of microRNAs in gene expression and disease is well recognized. However, what is less appreciated is that almost half of miRNA genes are organized in polycistronic clusters and are therefore co-expressed. The mir-11~998 cluster consists of two miRNAs, miR-11 and miR-998. Here, we describe a novel layer of regulation that links the processing and expression of miR-998 to the presence of the mir-11 gene. We show that the presence of mir-11 in the pri-miRNA is required for processing by Drosha, and deletion of mir-11 prevents the expression of miR-998. Replacing mir-11 with an unrelated miRNA rescued miR-998 expression in vivo and in vitro, as did expressing miR-998 from a shorter, more canonical miRNA scaffold. The embedded regulation of miR-998 is functionally important because unchecked miR-998 expression in the absence of miR-11 resulted in highly penetrant pleiotropic developmental defects. We further show that this novel regulation of expression of miRNAs within a cluster is not limited to the mir-11~998 cluster and likely reflects the more general cis-regulation of expression of individual miRNAs. Thus, our results reveal a novel layer of regulation within miRNA clusters that tempers the functions of the individual miRNAs. Unlinking their expression has the potential to change the expression of multiple miRNA targets and shift biological response. Overall design: RNA was extracted from Drosophila third instar larval eye discs of animals grown in standard conditions; Illumina HiSeq2000 Next Gen RNA Sequencing was performed, and differential expression of genes was assessed in wild-type vs unchecked miR-998 expression
Novel regulation and functional interaction of polycistronic miRNAs.
Specimen part, Subject
View SamplesExpression of dE2F1 induces proliferation and apoptosis. We sought to perform an unbiased analysis of the effect of co-expression of miR-11
mir-11 limits the proapoptotic function of its host gene, dE2f1.
Specimen part
View SamplesWe used microarrays to identify genes that are differentially expressed in the absence of miR-998 expression.
An intronic microRNA links Rb/E2F and EGFR signaling.
Specimen part
View SamplesDerivation of induced smooth muscle cells (iSMC) through direct transdifferentiation of a convenient and expandable primary cell source would open a wide range of prospects for their use in tissue engineering, drug testing, and disease modeling. Hypothesizing that MYOCD as a master regulator of smooth muscle gene expression would facilitate the generation of iSMC, we studied the conversion of human endothelial progenitor cells (EPC) into iSMC through the induced expression of by over-expression of MYOCD. A significant cytoskeletal rearrangement of the EPC resembling that of mesenchymal cells occurred within 3 days post initiation of MYOCD expression. This transition was associated with a downregulation of endothelial cell surface markers (CD31, CD105) as determined by flow cytometry. By day 7, iSMC derivation was evident with a significant upregulation of smooth muscle markers ACTA2, MYH11, TAGLN, and downregulation of CD31 and CDH5 as determined by gene expression analysis. Immunofluorescence revealed expression of MYH11 and ACTA2 and absence of endothelial markers VWF and CD31. By two weeks, microarray gene expression analysis demonstrated a significant similarity between iSMC and umbilical artery SMC (UASMC). The iSMC continued to develop toward the SMC lineage after four weeks of MYOCD induced expression. Microarray gene expression analysis showed an upregulation of molecular pathways associated with smooth muscle contraction and cytoskeletal reorganization in iSMC. Calcium transients were detected in iSMC when stimulated with phenylephrine but not in EPC. Contractility of iSMC was also higher than that of EPC as determined by traction force microscopy. Tissue-engineered blood vessels constructed using iSMC showed functionality with respect to flow- and drug- mediated vasodilation and vasoconstriction.
Transdifferentiation of human endothelial progenitors into smooth muscle cells.
Time
View SamplesRationale: Asthma is a chronic inflammatory airway disease. Children with severe asthma have lower levels of vitamin D than children with moderate asthma, and among children with severe asthma, airway smooth muscle (ASM) mass is inversely related to vitamin D levels. Beta2 agonists are a common asthma medication that act partly by targetting the ASM. We used RNA-Seq to characterize the human ASM transcriptome of fatal and asthma vs. contols at baseline and under two treatment conditions. Methods: The Illumina TruSeq assay was used to prepare 75bp paired-end libraries for ASM cells from white donors, 6 with fatal asthma and 12 control donors under three treatment conditions: 1) no treatment; 2) treatment with a ß2-agonist (i.e. Albuterol, 1µM for 18h); 3) treatment with vitamin D 100 nM for 18h). Llibraries were sequenced with an Illumina Hi-Seq 2000 instrument. The Tuxedo Suite Tools were used to align reads to the hg19 reference genome, assemble transcripts, and perform differential expression analysis using the protocol described in https://github.com/blancahimes/taffeta Overall design: mRNA profiles obtained via RNA-Seq for primary human airway smooth muscle cell lines from fatal asthma or control donors that were treated with vitamin D, albuterol, or were left untreated.
Vitamin D Modulates Expression of the Airway Smooth Muscle Transcriptome in Fatal Asthma.
No sample metadata fields
View SamplesGoals of this study were to identify new candidates involved in the development of the Atrioventricular cushions in the mouse heart.
Cartilage link protein 1 (Crtl1), an extracellular matrix component playing an important role in heart development.
No sample metadata fields
View SamplesIncreasing evidence suggests that cancer arises from cells that are capable of initiating and sustaining neoplastic tissue growth, termed cancer stem cells (CSCs). Of central scientific and clinical relevance, cells with CSC properties are enriched for chemo- and radiation resistance and therefore may represent a population of cells that must be therapeutically targeted to prevent cancer recurrence/relapse 1. Human CSCs were first isolated in neoplastic hematopoietic tissue that manifests leukemias such as adult acute myeloid leukemia (AML) 2. AML stem cells represent a benchmark model of human CSC biology, ultimately motivating foundational studies leading to the identification of CSCs from solid tumours such as breast and colon 3. Independent of tissue type, a consistent feature of CSCs is their uncontrolled self-renewal capacity and differentiation blockade that have been commonly related to aberrant activation of pro-oncogenic events such as dysregulation of CBP/p300 transcriptional regulation involving -catenin 4. However, the transcriptional networks involving CBP/p300/-catenin complex have been shown to be equally critical to maintain normal stem cell (SCs) self-renewal for tissue homeostasis and regeneration 5. Here, we identify Sam68 as a distinct target that affords the ability to uniquely regulate CBP mediated transcription in human CSCs. Using a small molecule that targets Sam68, we reveal that shifting its affinity for CBP disrupts CBP/-catenin complexes, leading to immediate changes in histone H3 (K14 and K18) acetylation. Chemical targeting of Sam68 induced global changes in transcriptional programs of patient AML cells involving apoptosis and differentiation and was able to uniquely reduce neoplastic self-renewal of human CSCs in an in vivo model of patient specific acute myeloid leukemia (AML). Our study establishes an approach whereby the CBP/-catenin transcriptome can be uniquely targeted via Sam68 based vulnerability of CSCs that impacts neoplastic differentiation and self-renewal.
Sam68 Allows Selective Targeting of Human Cancer Stem Cells.
Specimen part, Treatment
View SamplesGlioblastoma multiforme is the most common and most aggressive type of primary brain tumor. The brain-infiltrative character of glioblastoma makes complete surgical removal of the tumor impossible and neither radiation nor current chemotherapy provide cure. Recent evidence shows that glioblastoma multiforme consists of heterogeneous cell populations which differ in tumor-forming potential. Enriched tumor-initiating capacity has been linked to poorly differentiated glioblastoma cells sharing features with neural stem cells. Thus, these cells are important targets for new therapeutic strategies.
An RNAi screen identifies TRRAP as a regulator of brain tumor-initiating cell differentiation.
Cell line
View Samples