Project description:Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor, SOX9, is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and disrupts valve formation. Despite this important role, little is known regarding how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in embryonic day (E) 12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Consequently, we compared regions of putative SOX9 DNA-binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and contextâindependent SOX9 interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9 interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom/Evi1 and Pitx2. Together, our data identifies SOX9 coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation. Examination of SOX9 binding sites in E12.5 atrioventricular canal (AVC) and E12.5 embryonic limb and mRNA expression profiling in E12.5 WT and Sox9 mutant AVCs, in duplicate.
Project description:Calcific aortic valve disease (CAVD) is an slowly progressive calcification of heart valve which leads to aortic stenosis. The only existing treatment of CAVD is surgical replacment of calcified valve - development of anti-CAVD treatment is urgent task. For better understanding of molecular mechanisms of CAVD progression we performed proteomics analysis of osteogenic differentiation of human valve interstitial cells isolated from healthy humans or patients with CAVD.
Project description:Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor, SOX9, is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and disrupts valve formation. Despite this important role, little is known regarding how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in embryonic day (E) 12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Consequently, we compared regions of putative SOX9 DNA-binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and context–independent SOX9 interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9 interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom/Evi1 and Pitx2. Together, our data identifies SOX9 coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation.
Project description:E12.5 AV cushion and E17.5 AV valve from wild-type FVB/N mice and in vitro cultured MC3T3 cells In the study we demonstrated shared gene expression in embryonic heart valve development and Osteoblast progenitor cells. The atrioventricular (AV) valves of the heart develop from undifferentiated mesenchymal endocardial cushions, that later remodel into stratified valves with diversified extracellular matrix (ECM). Because the mature valves express genes associated with osteogenesis and exhibit disease-associated calcification, we hypothesized the existence of shared regulatory pathways active in the remodeling AV valves and in bone progenitor cells. In order to define gene regulatory programs of valvulogenesis relative to osteoblast progenitors, we undertook Affymetrix gene expression profiling analysis of murine embryonic day (E)12.5 AV cushions compared to E17.5 remodeled AV valves (mitral and tri-cuspid) and to pre-osteoblast MC3T3-E1 (subclone4) cells. Overall MC3T3 cells were significantly more similar to E17.5 valves than to E12.5 cushions, supporting the hypothesis that valve remodeling involves the expression of many genes also expressed in osteoblasts. Several transcription factors characteristic of mesenchymal and osteoblast precursor cells, including Twist1 are predominant in E12.5 cushion. Valve remodeling also includes differential regulation of matrix metalloproteinases and their inhibitors as well as characteristic collagen isoform switching. Among the most highly enriched genes during valvulogenesis were members of the small leucine-rich proteoglycan (SLRP) family including Asporin, a known negative regulator of osteoblast differentiation and mineralization. Together, these data support shared gene expression profiles of the remodeling valves and osteoblast bone precursor cells in normal valve development and homeostasis with potential functions in calcific valve disease. Keywords: Embryonic valve development time point
Project description:Over 1.6 million Americans suffer from significant tricuspid valve leakage. In most cases this leakage is designated as secondary. Thus, valve dysfunction is assumed to be due to valve extrinsic factors. We challenge this paradigm and hypothesize that the tricuspid valve maladapts in those patients rendering the valve at least partially culpable for its dysfunction. As a first step in testing this hypothesis, we set out to demonstrate that the tricuspid valve maladapts in disease. To this end, we induced biventricular heart failure in sheep that developed tricuspid valve leakage. In the anterior leaflets of those animals, we investigated maladaptation on multiple scales. We demonstrated alterations on the protein and cell-level, leading to tissue growth, thickening, and stiffening. These data provide a new perspective on a poorly understood, yet highly prevalent disease. Our findings may motivate novel therapy option for many currently untreated patients with leaky tricuspid valves.