Project description:This study has two main goals. The first is to define a gene expression atlas of heart valve cells and identify cell heterogeneity within postnatal heart valve development. The second is to identify interstitial cell populations involved in ECM remodeling during postnatal heart valve development. Overall design: Using droplet RNA sequencing, transcriptomes of single cells from P7 and P30 murine aortic and mitral heart valves were analyzed.
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: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:Aortic valve calcific disease (CAVD) is a common heart valve condition typically characterized by severe narrowing of the aortic valve. Our previous research has shown that circHIPK3 is downregulated in calcified aortic valve tissues and plays a role in regulating the progression of CAVD. To further investigate how circHIPK3 exerts its inhibitory effects on aortic valve calcification, we overexpressed circHIPK3 in aortic valve interstitial cells and conducted RNA-seq analysis, revealing that circHIPK3 regulates key factors in the Wnt signaling pathway. These findings contribute to a deeper understanding of the molecular mechanisms underlying CAVD, particularly the potential involvement of circRNAs in this disease.
Project description:Although calcific aortic valve stenosis (CAVS) is the most prevalent valvular heart disease, the molecular mechanisms underlying aortic valve calcification remain unknown. Here, we found a significant elevation in stanniocalcin-1 (STC1) expression in the valve interstitial cells (VICs) of calcific aortic valves by combined analysis of our comprehensive gene expression data and microarray datasets reported previously. Immunohistochemical staining showed that STC1 was located around the calcific area in the aortic valves of patients with CAVS. In vitro experiments using inhibitors and siRNA targeting osteoblast differentiation signaling revealed that activation of the Akt/STC1 axis was essential for runt-related transcription factor 2 (RUNX2) induction in the VICs. RNA sequencing and bioinformatics analysis of STC1-knocked down VICs in osteoblast differentiation medium resulted in silencing of the induction of osteoarthritis signaling-related genes, including RUNX2 and COL10A1. STC1 depletion in the murine CAVS model improved aortic valve dysfunction with high peak velocity and valve thickening and suppressed the appearance of osteochondrocytes. STC1-deficient mice also exhibited complete calcification abolishment, although partial valve thickening by aortic valve injury was observed. Our findings suggest that STC1 may be a critical factor in determining valve calcification and a novel target for preventing the transition to severe CAVS with calcification. We analyzed the gene expression profiles of the valve interstitial cells (VICs) isolated from noncalcific and calcific areas in calcific aortic valve stenosis (CAVS) donors using a gene microarray.
Project description:Aortic valve calcification is a significant and serious clinical problem for which there are no effective medical treatments. Individuals born with bicuspid aortic valves, 1-2% of the population, are at the highest risk of developing aortic valve calcification. Aortic valve calcification involves increased levels of calcification and inflammatory genes. Bicuspid aortic valve leaflets experience increased strain. The molecular mechanisms involved in the pathogenesis of calcification of BAVs are not well understood, especially the molecular response to mechanical stretch. HOTAIR is a long non-coding RNA (lncRNA) that has been implicated with cancer but has not been studied in cardiac disease. We have found that HOTAIR levels are decreased in BAVs and in human aortic interstitial cells (AVICs) exposed to cyclic stretch. Reducing HOTAIR levels via siRNA in AVICs results in increased expression of calcification genes.
Project description:Cardiac valve structure and function are complex and include dynamic interactions between cells, extracellular matrix (ECM) and their hemodynamic environment. Valvular gene expression is tightly regulated by a variety of mechanisms including epigenetic factors such as histone modifications, RNA-based mechanisms and DNA methylation. To date, methylation fingerprints of non-diseased human aortic and mitral valves have not been studied. In this work we analyzed the differential methylation profiles of 12 non-diseased aortic and mitral valve tissue samples (in matched pairs). Analysis of methylation data (reduced representation bisulfite sequencing (RRBS)) of 1601 promoters genome-wide revealed 584 differentially methylated (DM) promoters, of which 13 were reported in endothelial mesenchymal trans-differentiation (EMT), 37 in aortic and mitral valve disease and 7 in ECM remodeling. Both functional classification as well as network analysis showed that the genes associated with the DM promoters were enriched for WNT-, Cadherin-, Endothelin-, PDGF- and VEGF- signaling implicated in valvular physiology and pathophysiology. Additional enrichment was detected for TGFB-, NOTCH- and Integrin- signaling involved in EMT as well as ECM remodeling. This data provides the first insight into differential regulation of human aortic and mitral valve tissue and identifies candidate genes linked to DM promoters. Our work will improve the understanding of valve biology, valve tissue engineering approaches and contributes to the identification of relevant drug targets.