Objective: Shear forces play a key role in the maintenance of vessel wall integrity. Current understanding regarding shear-dependent gene expression is mainly based on in vitro or in vivo observations with experimentally deranged shear, hence reflecting acute molecular events in relation to flow. Our objective was to combine computational fluid dynamic (CFD) simulations with global microarray analysis to study flow-dependent vessel wall biology in portions of the entire aorta under physiological conditions. Methods and Results: Animal-specific WSS magnitude and vector direction were estimated using CFD based on aortic geometry and flow information acquired by MRI. Two distinct flow pattern regions were identified in the normal rat aorta; the distal part of the inner curvature being exposed to low WSS and a non-uniform vector direction, and a region along the outer curvature being subjected to markedly higher levels of WSS and a uniform vector direction. Microarray analysis identified numerous novel mechanosensitive genes, including Hand2, trpc4 and slain2, and confirmed well-known ones, such as klf2 and BMP4. Three genes were further validated for protein , including Hand2, which showed higher expression in the endothelium in regions exposed to disturbed flow. Gene ontology analysis revealed an over-representation of genes involved in transcriptional regulation.
Characterization of shear-sensitive genes in the normal rat aorta identifies Hand2 as a major flow-responsive transcription factor.
Specimen part
View SamplesPurpose: Identifying target genes of the two human chromatin remodeling enzymes CHD3 and CHD4 Methods: see below in protocols Results: Libraries were sequenced on Illumina HiSeq2000 platform resulting in 37-71 Mio 50 bp paired-end reads per sample. We identified 16 (i) and 115 (ii) distinctly regulated genes when CHD3-GFP (i) or CHD4-GFP (ii) were overexpressed. Nine genes seem to be commonly regulated by CHD3 and CHD4. We successfully validated four genes from our RNA-seq via qPCR with two new (independent from those, used for RNA-seq) biological replicates. Conclusion: CHD3 and CHD4 regulate distinct genes. Overall design: Total RNA was prepared from 24 hours induced (1 ng/µl Dox) and non-induced Flp-In™ T-REx™ 293 cells, expressing GFP, hCHD3-GFP (UniProt: Q12873) or hCHD4-GFP(UniProt Q14839). Library preparation and Illumina Sequencing was perfprmed by EMBL GeneCore facility in Heidelberg (Germany: Dr. Vladimir Benes)
CHD3 and CHD4 form distinct NuRD complexes with different yet overlapping functionality.
Cell line, Subject
View SamplesThe molecular events during nongenotoxic carcinogenesis and their temporal order are poorly understood but thought to include long-lasting perturbations of gene expression. Here, we have investigated the temporal sequence of molecular and pathological perturbations at early stages of phenobarbital (PB) mediated liver tumor promotion in vivo. Molecular profiling (mRNA, microRNA [miRNA], DNA methylation, and proteins) of mouse liver during 13 weeks of PB treatment revealed progressive increases in hepatic expression of long noncoding RNAs and miRNAs originating from the Dlk1-Dio3 imprinted gene cluster, a locus that has recently been associated with stem cell pluripotency in mice and various neoplasms in humans. PB induction of the Dlk1-Dio3 cluster noncoding RNA (ncRNA) Meg3 was localized to glutamine synthetase-positive hypertrophic perivenous hepatocytes, sug- gesting a role for -catenin signaling in the dysregulation of Dlk1-Dio3 ncRNAs. The carcinogenic relevance of Dlk1-Dio3 locus ncRNA induction was further supported by in vivo genetic dependence on constitutive androstane receptor and -catenin pathways. Our data identify Dlk1-Dio3 ncRNAs as novel candidate early biomarkers for mouse liver tumor promotion and provide new opportunities for assessing the carcinogenic potential of novel compounds.
Identification of Dlk1-Dio3 imprinted gene cluster noncoding RNAs as novel candidate biomarkers for liver tumor promotion.
Specimen part
View Samples