Abstract 19219: Distinct Cardiac Microvascular Endothelium-specific Gene Signatures in Experimental Pressure-overload Heart Failure
Introduction: Pressure overload-induced heart failure is associated with a distinct molecular phenotype at the level of cardiac myocytes or fibroblasts. The role and phenotypic changes of microvascular endothelial cells (MiVEC) in the presence of sustained pressure overload are not known.
Methods: Accordingly, we randomized 10 male Tie2-GFP transgenic heterozygote mice (FVB, age 10±2.5 weeks) to transverse aortic constriction (TAC) for 10 weeks or to sham surgery. At 10 weeks, TAC animals displayed cardiac hypertrophy (heart/body weight: 5.3±0.2 vs. 3.0±0.8 mg/g, P<0.05) with LV dilation and dysfunction (LVID-D: 4.8±0.2 vs. 2.6±0.1 mm, P<0.05; fractional shortening: 28.0±1.8 vs. 33.0±1.8%, P <0.05) as compared to sham controls. Cardiac endothelial cells were purified using FACS for subsequent RNA extraction and sequencing (NextSeq500, Illumina, 13 to 18 million reads/sample). Three-fold changes in RNA expression were considered significant.
Results: After FACS, 99% of the extracted GFP+ cells showed surface expression of the MiVEC lineage markers CD31, CD34, and CD36, and were uniformly negative for CD45. RNA expression analysis revealed more than three-fold upregulation of 16 genes after TAC compared to sham. Among these genes, 11 encoded secreted proteins. They are involved in the regulation of the hypertrophic growth response (Thrombospondin 4, Microfibrillar associated protein 5), collagen content (MMP-2, Collagen XVα1) and angiogenic signaling (Endothelial cell specific molecule 1, Ectonucleoside triphosphate diphosphohydrolase 2) or endocrine function (Natriuretic peptide type A). Ingenuity Pathway Analysis revealed upstream targets involved mainly in the signal transduction of the transforming growth factor (TGF) β pathway. Only one gene with unknown function (6720456H20Rik) showed a significant down-regulation in TAC vs. sham.
Conclusions: In summary, experimental pressure overload-induced heart failure is associated with a distinct molecular signature of MiVEC with upregulation of mainly secretory proteins. This suggests the potential paracrine interaction of MiVEC with surrounding cardiac myocytes and fibroblasts in the pathophysiology of hypertrophic remodeling and progression to heart failure.
Author Disclosures: S. Trenson: None. A. Walravens: None. E. Caluwé: None. S. Vandenwijngaert: None. G. Coppiello: None. M. Swinnen: None. J. Bartunek: None. A. Luttun: None. S. Janssens: None.
- © 2014 by American Heart Association, Inc.