Project description:Microarray gene expression profiling of the minimally cultured human heart valve interstitial and endothelial cells with and without treatment with BMP4 and TGFB3 signaling molecules
Project description:Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD) are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs). We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of expression Sox9 has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism. 3 samples of aortic valve interstitial cells treated with DAPT were compared with 3 samples of aortic valve interstitial cells treated with DMSO
Project description:Valvular heart disease presents a significant health burden, yet advancements in valve biology and novel therapeutics have been hindered by the lack of accessibility to human valve cells. In this study, we have developed a scalable and feeder-free method to differentiate human induced pluripotent stem cells (iPSCs) into endocardial cells. Importantly, we show that these endocardial cells are transcriptionally and phenotypically distinct from vascular endothelial cells and can be directed to undergo endothelial-to-mesenchymal transition (EndMT) to generate cardiac valve cell populations. Following this, we identified two distinct populations—one population undergoes EndMT to become valvular interstitial cells (VICs), while the other population reinforces their endothelial identity to become valvular endothelial cells (VECs). We then characterized our iPSC-derived cell populations and identified putative markers for these populations through bulk RNAseq transcriptome analyses. Lastly, we validated our VIC and VEC populations by comparing our transcriptomic data to pseudobulk data generated from single-cell RNAseq of normal valve tissue from a 15-week-old human fetus. By increasing the accessibility to these cell populations, we aim to accelerate discoveries for cardiac valve biology and disease.
Project description:Calcific aortic valve disease (CAVD) primarily involves osteogenic differentiation in human aortic valve interstitial cells (hVICs). Schisandrol B (SolB), a natural bioactive constituent, has known therapeutic effects on inflammatory and fibrotic disorders. However, its impact on valve calcification has not been reported. Transcriptome sequencing was used to analyze potential molecular pathways affected by SolB treatment. To explore the therapeutic mechanism of SolB, human valve interstitial cells were induced to undergo osteogenic differentiation by OM, with or without SolB treatment meanwhile. Among the signaling pathways enriched, the P53 signaling pathway was identified as the upstream regulator of other enriched pathways such as Cell cycle, Oocyte meiosis, Cytokine-cytokine receptor interactions. These pathways were regulated by the P53 signaling pathway and were reported to be stimulated by DNA damage, an early stage of pathological change in CAVD. The cytokine-cytokine receptor interaction signaling pathway was reported to correlate with calcified aortic valve disease. taken together, our data revealed potential therapitic mechanism p53 signaling of Schisandrol B treatment in hVICs calcification.
Project description:To explore the miR expression profile of calcified valve interstitial cells (VICs) induced by high calcium/phosphate, identify the key miRNA in the calcification process of VICs, and probe effect of miRs in regulating valve calcification.
Project description:Valve remodeling is a complex process involving extracellular matrix organization, development of trilaminar structures, and physical elongation of valve leaflets. However, the cellular and molecular mechanisms regulating valve remodeling and their roles in congenital valve disorders remain poorly understood. Semilunar valves and atrioventricular valves from healthy and age-matched human fetal hearts with pulmonary stenosis (PS) were collected. Single-Cell RNA-sequencing (scRNA-seq) was performed to determine the transcriptomic landscape of multiple valvular cell subtypes in valve remodeling and disease. Spatial localization of newly-identified cell subtypes was determined via immunofluorescence and RNA in situ hybridization. The molecular mechanisms mediating valve development was investigated utilizing primary human fetal valve interstitial cells (VICs) and endothelial cells (VECs). scRNA-seq analysis of healthy human fetal valves identified a novel APOE+ elastin-producing VIC subtype (Elastin-VIC) spatially located underneath VECs sensing the unidirectional flow. Knockdown of APOE in fetal VICs resulted in significant elastogenesis defects. In pulmonary valve with PS, we observed decreased expression of APOE and other genes regulating elastogenesis such as EMILIN1 and LOXL1, as well as elastin fragmentation. These findings suggested the crucial role of APOE in regulating elastogenesis during valve remodeling. Furthermore, cell-cell interaction analysis revealed that JAG1 from unidirectional VECs activates NOTCH signaling in Elastin-VICs through NOTCH3. In vitro Jag1 treatment in VICs increased the expression of elastogenesis-related genes and enhanced contractile functions with related gene expression. This was accompanied by activation of NOTCH signaling and elastogenesis observed in VICs co-cultured with VECs in the presence of unidirectional flow. Notably, we found that the JAG1-NOTCH3 signaling pair was drastically reduced in the PS valves. Lastly, we demonstrated that APOE is indispensable for JAG1-induced NOTCH activation in VICs, reinforcing the presence of a synergistic intrinsic and external regulatory network involving APOE and NOTCH signaling that is responsible for regulating elastogenesis during human valve remodeling. scRNA-seq analysis of human fetal valves identified a novel Elastin-VIC subpopulation, and revealed mechanism of intrinsic APOE and external NOTCH signaling from VECs sensing unidirectional flow in regulating elastogenesis during valve remodeling. These mechanisms may contribute to the pathogenesis of elastic malformation in congenital valve disease.
Project description:Aortic valve calcifications are often associated with calcium deposition and tissue mineralization, resulting in stiffness and dysfunction. To better understand the diversity of molecular and cellular processes for calcification in valve structures, we isolated human aortic valve interstitial cells (AVICs) and exposed them to calcification stimulation. RNA-seq revealed that in response to calcified stimuli, AVIC activates a robust ossification program, although the signaling pathways, cellular processes, and osteogenesis-related markers involved are diverse. In conclusion, this study provides a wealth of information suggesting that the pathogenesis of aortic valve calcification may be much more than previously understood.