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Expression data from mouse aortas

ABSTRACT: Aortic aneurysm is a life-threatening cardiovascular disorder due to the predisposition for dissection and rupture. Genetic studies have proved the involvement of the transforming growth factor-β (TGF-β) pathway in aortic aneurysm. Smad4 is the central mediator of canonical TGF-β signaling. However, the exact role of Smad4 confined to the smooth muscle cells (SMCs) in the pathogenesis of aortic aneurysm is largely unknown. Furthermore, whether TGF-β signaling disruption in SMCs could directly trigger aortic wall inflammation remains poorly investigated. Recently, we revealed a pivotal role of smooth muscle Smad4 signaling in maintaining aortic wall homeostasis and protecting against the development of aortic aneurysm and dissection. To evaluate the underlying mechanism by which Smad4 regulate VSMC functions and affects aneurysm formation and development, Smooth muscle specific Smad4 Knockout mice and the control littermate were sacrificed at 6 weeks old, and their aortic ateries were collected.We combined 3-5 vessels for one sample, and 2 samples for each phenotype. Subsequently, a total of 400ng RNA was used following Affymetrix instruction and 2 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 aortic arteries of smooth muscle cell specific Smad4 knockout mice (Smad4-KO)compared with wild type littermates (WT) at 6 weeks old and identified distinct classes of altered genes.

ORGANISM(S): Mus musculus

PROVIDER: GSE67182 | GEO | 2016/12/01

SECONDARY ACCESSION(S): PRJNA279198

REPOSITORIES: GEO

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Project description:OBJECTIVE: When aortic cells are under stress, such as increased hemodynamic pressure, they adapt to the environment by modifying their functions, allowing the aorta to maintain its strength. To understand the regulation of this adaptive response, we examined the transcriptomic and epigenomic programs in aortic smooth muscle cells (SMCs) during the adaptive response to angiotensin II (AngII) infusion and determined its importance in protecting against aortic aneurysm and dissection. APPROACH AND RESULTS: In wild-type mice, AngII infusion increased medial thickness in the thoracic aorta. Single-cell RNA sequencing analysis revealed an adaptive response in thoracic SMCs characterized by the upregulation of genes with roles in wound healing, elastin and collagen production, proliferation, migration, cytoskeleton organization, cell-matrix focal adhesion, and AKT and TGF-β signaling. Further single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) analysis showed increased chromatin accessibility at the regulatory regions of adaptive genes and revealed the mechanical sensor YAP/TEADs as a top candidate transcription complex driving the increased abundance of these gene transcripts (e.g., Lox, Col5a2 and Tgfb2). In cultured human aortic SMCs, cyclic stretch activated YAP, which directly bound to the regulatory regions of the adaptive genes (e.g., Lox) and increased the abundance of their transcripts. Finally, SMC-specific Yap deletion in mice compromised this adaptive response in SMCs, leading to an increased incidence of aortic aneurysm and dissection and a trend of increased rupture. CONCLUSIONS: Aortic stress triggers the systemic epigenetic induction of adaptive response (e.g., wound healing, proliferation, and matrix organization) in thoracic aortic SMCs, that depends on functional biomechanical signal transduction (e.g., YAP signaling). Our study highlights the importance of the adaptive response in maintaining aortic homeostasis and preventing aortic disease development in mice.

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Expression data from mouse aortas

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