Atrial fibrillation (AF) is a progressive arrhythmia for which current therapy is inadequate. During AF, rapid stimulation causes atrial remodeling that promotes further AF. The cellular signals that trigger this process remain poorly understood, however, and elucidation of these factors would likely identify new therapeutic targets. We have previously shown that immortalized mouse atrial (HL-1) myocytes subjected to 24 hr of rapid stimulation in culture undergo remodeling similar to that seen in animal models of atrial tachycardia (AT) and human AF. This preparation is devoid of confounding in vivo variables that can modulate gene expression (e.g., hemodynamics). Therefore, we investigated the transcriptional profile associated with early atrial cell remodeling. RNA was harvested from HL-1 cells cultured for 24 hr in the absence and presence of rapid stimulation and subjected to microarray analysis. Data were normalized using Robust Multichip Analysis (RMA), and genes exhibiting significant differential expression were identified using the Significance Analysis of Microarrays (SAM) method. Using this approach, 919 genes were identified that were significantly altered with rapid stimulation (763 up-regulated and 156 down-regulated). For many individual transcripts, changes typical of AF/AT were observed, with marked up-regulation of genes encoding BNP and ANP precursors, heat shock proteins, and MAP kinases, while novel signaling pathways and molecules were also identified. Both stress and survival response were evident, as well as up-regulation of multiple transcription factors. Genes were also functionally classified based on cellular component, biologic process, and molecular function using the Gene Ontology database to permit direct comparison of our data with other gene sets regulated in human AF and experimental AT. For broad categories of genes grouped by functional classification, there was striking conservation between rapidly stimulated HL-1 cells and AF/AT. Results were confirmed using real-time quantitative RT-PCR on 13 genes selected by physiological relevance in AF/AT and regulation in the microarray analysis (up, down, and nonregulated). Rapidly-stimulated atrial myocytes provide a complementary experimental paradigm to explore the initial cellular signals in AT remodeling to identify novel targets in the treatment of AF.
No associated publication
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Experimentally derived metastasis gene expression profile predicts recurrence and death in patients with colon cancer.
Sex, Age, Disease stage, Race
View SamplesFrom preliminary experiments, HSP70 deficient MEF cells display moderate thermotolerance to a severe heatshock of 45.5 degrees after a mild preshock at 43 degrees, even in the absence of hsp70 protein. We would like to determine which genes in these cells are being activated to account for this thermotolerance.
Microarray analysis of cellular thermotolerance.
No sample metadata fields
View SamplesBMPR2 mutation causes pulmonary arterial hypertension (PAH); ACE2 treatment can resolve established BMPR2-mediated PAH. The purpose of this study was to uncover the molecular mechanism behind this.
Cytoskeletal defects in Bmpr2-associated pulmonary arterial hypertension.
Sex, Specimen part, Treatment
View SamplesRationale: While modulation of the serotonin transporter (5HTT) has shown to be a risk factor for pulmonary arterial hypertension for almost 40 years, there is a lack of in vivo data about the broad molecular effects of pulmonary inhibition of 5HTT. Previous studies have suggested effects on inflammation, proliferation, and vasoconstriction. The goal of this study was to determine which of these were supported by alterations in gene expression in serotonin transporter knockout mice. Methods: Eight week old normoxic mice with a 5-HTT knock-out (5HTT-/-) and their heterozygote(5HTT+/-) or wild-type(5HTT+/+) littermates had right ventricular systolic pressure(RVSP) assessed, lungs collected for RNA, pooled, and used in duplicate in Affymetrix array analysis. Representative genes were confirmed by quantitative RT-PCR and western blot. Results: RVSP was normal in all groups. Only 124 genes were reliably changed between 5HTT-/- and 5HTT+/+ mice. More than half of these were either involved in inflammatory response or muscle function and organization; in addition, some matrix, heme oxygenase, developmental, and energy metabolism genes showed altered expression. Quantitative RT-PCR for examples from each major group confirmed changes seen by array, with an intermediate level in 5HTT+/- mice. Conclusions: These results for the first time show the in vivo effects of 5HTT knockout in lungs, and show that many of the downstream mechanisms suggested by cell culture and ex vivo experiments are also operational in vivo. This suggests that the effect of 5HTT on pulmonary vascular function arises from its impact on several systems, including vasoreactivity, proliferation, and immune function.
Gene expression in lungs of mice lacking the 5-hydroxytryptamine transporter gene.
No sample metadata fields
View SamplesFamilial pulmonary arterial hypertension (fPAH) is associated with mutations in BMPR2. Many of these mutations occur in the BMPR2 tail domain, leaving the SMAD functions intact. In order to determine the in vivo consequences of BMPR2 tail domain mutation, we created a smooth-muscle specific doxycycline inducible BMPR2 mutation with an arginine to termination mutation at amino acid 899. When these SM22-rtTA x TetO7-BMPR2R899X mice had transgene induced for 9 weeks, starting at 4 weeks of age, they universally developed pulmonary vascular pruning as assessed by fluorescent microangiography. Approximately half the time the induced animals developed elevated right ventricular systolic pressures (RVSP), associated with extensive pruning, muscularization of small pulmonary vessels, and development of large structural pulmonary vascular changes. These lesions included large numbers of macrophages and T-cells in their adventitial compartment, as well as CD133 positive cells in the lumen. Small vessels filled with CD45 positive and sometimes CD3 positive cells were a common feature in all SM22-rtTA x TetO7-BMPR2R899X mice. Gene array experiments show changes in stress response, muscle organization and function, proliferation and apoptosis, and developmental pathways before RVSP increases. Our results show that the primary phenotypic result of BMPR2 tail domain mutation in smooth muscle is pulmonary vascular pruning leading to elevated RVSP, associated with early dysregulation in multiple pathways with clear relevance to PAH. This model should be useful to the research community in examining early molecular and physical events in the development of PAH, and as a platform to validate potential treatments.
Mice expressing BMPR2R899X transgene in smooth muscle develop pulmonary vascular lesions.
No sample metadata fields
View SamplesFunctional genomics approach to metastatic colon cancer
Experimentally derived metastasis gene expression profile predicts recurrence and death in patients with colon cancer.
No sample metadata fields
View SamplesDifferential gene expression of cerebral cortex might be responsible for distinct neurovascular developments between different mouse strains
A novel genetic locus modulates infarct volume independently of the extent of collateral circulation.
Sex, Specimen part
View SamplesIn order to elucidate the molecular mechanisms underlying individual variation in sensitivity to ethanol we profiled the prefrontal cortex transcriptomes of two inbred strains that exhibit divergent responses to acute ethanol, the C57BL6/J (B6) and DBA/2J (D2) strains, as well as 27 members of the BXD recombinant inbred panel, which was derived from a B6 x D2 cross. With this dataset we were able to identify several gene co-expression networks that were robustly altered by acute ethanol across the BXD panel. These ethanol-responsive gene-enriched networks were heavily populated by genes regulating synaptic transmission and neuroplasticity, and showed strong genetic linkage to discreet chromosomal loci. Network-based measurements of node importance identified several hub genes as established regulators of ethanol response phenotypes, while other hubs represent novel candidate modulators of ethanol responses.
Genetic dissection of acute ethanol responsive gene networks in prefrontal cortex: functional and mechanistic implications.
Sex, Specimen part
View SamplesThroughout postnatal life in mammals, neural stem cells (NSCs) are located in the subventricular zone (SVZ) of the lateral ventricles. The greatest diversity of neuronal and glial lineages they generate occurs during early postnatal life in a region-specific manner. In order to evaluate potential heterogeneity in the NSC pool, we microdissected the dorsal and lateral SVZ at different postnatal ages and isolated NSCs and their immediate progeny based on their expression of Hes5-EGFP/Prominin1 and Ascl1-EGFP, respectively. Whole genome comparative transcriptome analysis revealed transcriptional regulators as major hallmarks that sustain postnatal SVZ regionalization. Manipulation of single genes encoding for locally enriched transcription factors influenced NSC specification indicating that the fate of regionalized postnatal SVZ NSCs can be readily modified . These findings reveal functional heterogeneity of NSCs in the postnatal SVZ and provide targets to recruit region-specific lineages in regenerative contexts.
Transcriptional Hallmarks of Heterogeneous Neural Stem Cell Niches of the Subventricular Zone.
Specimen part
View Samples