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Expression data from mouse carotid arteries in response to wire-injury

ABSTRACT: IRF9 is ubiquitously expressed and mediates the effects of IFNs, previous study showed that IRF9 played an important role in immunity and cell fate decision. Our recent study revealed that IRF9 involved in cardiac hypertrophy, hepatic steatosis and insulin resistance. However, the function of IRF9 in VSMC and neointima formation was largely unknown. We found that IRF9 expression was significantly increased in the VSMCs of mouse carotid artery. More importantly, we generated SMC-specific IRF9 overexpression transgenic mice (IRF9 TG) and found that IRF9 TG significantly increased VSMC proliferation, migration and neointima formation compared with NTG mice in response to injury. To evaluate the underlying mechanism by which IRF9 promotes VSMC proliferation and migration after vascular injury, IRF9 TG and NTG mice were subjected to wire-injury and the carotid arteries were collected at 14 days post-injury. We combined 3-5 vessels for one sample, and 3 samples for each phenotype. Subsequently, a total of 400ng RNA was used following Affymetrix instruction and 10 ug of cRNA were hybridized for 16 hr at 45°. GeneChips were scanned using the Scanner 7G and the data was analyzed with Expression Console using Affymetrix default analysis settings and global scaling as normalization method. RMA analysis was employed to evaluate the gene expression. We used microarrays to detect the global gene expression in the carotid arteries of smooth muscle cell specific IRF9 transgenic mice(IRF9 TG) compared with non transgenic control mice (NTG) at 14 days post-injury and identified distinct classes of altered genes.

ORGANISM(S): Mus musculus

PROVIDER: GSE61046 | GEO | 2014/09/03

SECONDARY ACCESSION(S): PRJNA260155

REPOSITORIES: GEO

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Project description:IRF9 is ubiquitously expressed and mediates the effects of IFNs, previous study showed that IRF9 played an important role in immunity and cell fate decision. Our recent study revealed that IRF9 involved in cardiac hypertrophy, hepatic steatosis and insulin resistance. However, the function of IRF9 in VSMC and neointima formation was largely unknown. We found that IRF9 expression was significantly increased in the VSMCs of mouse carotid artery. More importantly, we generated SMC-specific IRF9 overexpression transgenic mice (IRF9 TG) and found that IRF9 TG significantly increased VSMC proliferation, migration and neointima formation compared with NTG mice in response to injury. To evaluate the underlying mechanism by which IRF9 promotes VSMC proliferation and migration after vascular injury, IRF9 TG and NTG mice were subjected to wire-injury and the carotid arteries were collected at 14 days post-injury. We combined 3-5 vessels for one sample, and 3 samples for each phenotype. Subsequently, a total of 400ng RNA was used following Affymetrix instruction and 10 ug of cRNA were hybridized for 16 hr at 45°. GeneChips were scanned using the Scanner 7G and the data was analyzed with Expression Console using Affymetrix default analysis settings and global scaling as normalization method. RMA analysis was employed to evaluate the gene expression. We used microarrays to detect the global gene expression in the carotid arteries of smooth muscle cell specific IRF9 transgenic mice(IRF9 TG) compared with non transgenic control mice (NTG) at 14 days post-injury and identified distinct classes of altered genes. non-transgenic controls mice (NTG) and smooth muscle specific IRF9 transgenic mice (IRF9 TG) were subjected to wire-injury and the carotid ateries were collected at 14 days post-injury. We combine 3-5 vessels in one tube and for a single Affymetrix microarray. Total RNA was extracted and a total of 400ng RNA was used following Affymetrix instruction. 3 biological samples for each genotype.

Project description:Vascular smooth muscle cell (VSMC) dysregulation is a hallmark of vascular disease, including atherosclerosis. In particular, the majority of cells within atherosclerotic lesions are generated from pre-existing VSMCs and a clonal nature has been documented for VSMC-derived cells in multiple disease models. However, the mechanisms underlying the generation of oligoclonal lesions and the phenotype of proliferating VSMCs are unknown.Here we analyse clonal dynamics in multi-color lineage-traced animals over time after vessel injury to understand the cellular mechanisms underlying clonal VSMC expansion in disease.We demonstrate that VSMC proliferation is initiated in a small fraction of VSMCs that initially expand clonally in the medial layer and then migrate to form the oligoclonal neointima. Selective activation of VSMC proliferation also occurs in vitro, suggesting that this is a cell-autonomous feature. Mapping of VSMC trajectories using single-cell RNA-sequencing reveals a continuum of cellular states after injury and suggests that VSMC proliferation initiates in cells that have downregulated the contractile phenotype and show evidence of pronounced phenotypic switching. We show that proliferation is associated with induced expression of stem cell antigen 1 (SCA1) and the expression signature previously identified in SCA1+ VSMCs in healthy arteries. A remarkably increased proliferation of SCA1+ VSMCs, directly validated in functional assays, indicates that SCA1+ VSMCs act as "first responders" in vascular injury. Early atherosclerotic lesions also had clonal VSMC contribution and we show that the proliferation-associated injury response is conserved in plaque VSMCs, extending these findings to atherosclerosis. Finally, we identify VSMCs in healthy human arteries that correspond to the SCA1+ state in mouse VSMCs and show that genes identified as differentially expressed in this human VSMC subpopulation are enriched for genes showing genetic association with cardiovascular disease. We show that cell-intrinsic, selective VSMC activation drives clonal proliferation after injury and in atherosclerosis. Our study suggests that healthy mouse and human arteries contain VSMCs characterised by expression of disease-associated genes that are predisposed for proliferation. Targeting such "first responder" cells in patients undergoing vascular surgery could effectively prevent injury-associated VSMC activation and neoatherosclerosis.

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Expression data from mouse carotid arteries in response to wire-injury

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