scholarly journals Differential Requirement of DICER1 Activity during Development of Mitral and Tricuspid Valves

2022 ◽  
Author(s):  
Shun Yan ◽  
Yin Peng ◽  
Jin Lu ◽  
Saima Shakil ◽  
Yang Shi ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Tricuspid Valve ◽  
Regulatory Mechanisms ◽  
Mitral Valve Stenosis ◽  
Sequencing Analysis ◽  
Ecm Remodeling ◽  
Mitral Valves ◽  
Valve Development ◽  
Single Cell Rna Sequencing ◽  
Cell Sources

Mitral and tricuspid valves are essential for unidirectional blood flow in the heart. They are derived from similar cell sources, and yet congenital dysplasia affecting both valves is clinically rare, suggesting the presence of differential regulatory mechanisms underlying their development. We specifically inactivated Dicer1 in the endocardium during cardiogenesis, and unexpectedly found that Dicer1-deletion caused congenital mitral valve stenosis and regurgitation, while it had no impact on other valves. We showed that hyperplastic mitral valves were caused by abnormal condensation and extracellular matrix (ECM) remodeling. Our single-cell RNA Sequencing analysis revealed impaired maturation of mesenchymal cells and abnormal expression of ECM genes in mutant mitral valves. Furthermore, expression of a set of miRNAs that target ECM genes was significantly lower in tricuspid valves compared to mitral valves, consistent with the idea that the miRNAs are differentially required for mitral and tricuspid valve development. Our study thus reveals miRNA-mediated gene regulation as a novel molecular mechanism that differentially regulates mitral and tricuspid valve development, thereby enhancing our understanding of the non-association of inborn mitral and tricuspid dysplasia observed clinically.

Abstract 122: Pharmacological Inhibition Of Macrophage Infiltration Prevents Myxomatous Valve Degeneration In Marfan Syndrome

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Na Xu ◽  
Katherine E Yutzey
Keyword(s):  
Immune Response ◽  
Extracellular Matrix ◽  
Marfan Syndrome ◽  
Macrophage Infiltration ◽  
Histological Evaluation ◽  
Matrix Remodeling ◽  
Ecm Remodeling ◽  
Mitral Valves ◽  
Fibrillin 1 ◽  
Underlying Mechanisms

Introduction: Myxomatous valve degeneration (MVD) is the most common cause of mitral regurgitation, characterized by valve leaflet thickening and progressive valve degeneration, leading to impaired cardiac function and heart failure. Currently, there is no medical therapy for the treatment of MVD. MVD in a mouse model of Marfan syndrome (MFS) is characterized leaflet thickening and increased macrophage infiltration, which are reduced with loss of C-C chemokine receptor type 2 (CCR2). However, the specific contributions of macrophages to pathological extracellular matrix (ECM) remodeling and underlying mechanisms are unknown. Hypothesis: Inhibition of macrophage infiltration by a CCR2 inhibitor blocks ECM abnormalities and MVD progression in mitral valves of MFS mice by suppressing the response to cytokine/chemokines. Methods: Mice with the mutation of Fibrillin 1 (Fbn1 C1039G/+ ) recapitulate histopathological features of MFS. Here, we tested the efficacy of a selective CCR2 antagonist RS504393 in the valves of MFS mice in the initiation (1-month-old) and the progression (2-month-old) of MVD, respectively. MFS mice were intraperitoneally injected with RS504393 at 2 mg/kg/d for 30 days. Histological evaluation and immunofluorescence for macrophages and ECM were performed. RNAseq was performed in mitral valves from 2-month old Fbn1 C1039G/+ mice with CCR2 knockout (CCR2 RFP/RFP ). Results: MFS valves revealed ECM abnormalities characterized by collagen fragmentation and proteoglycan accumulation. RS504393 treatment reduced infiltrating macrophages (MHCII+, CCR2+) in myxomatous valves. Remarkably, RS504393 was protective against both the initiation and the progression of MVD, detected by decreased mitral valve thickness and prevention of pathological ECM remodeling in MFS mice. RNAseq data confirmed increased leukocyte activation involved in immune response and abnormal extracellular matrix remodeling in MFS valves. CCR2 deficiency blocked macrophage infiltration and inhibited the response to cytokines in Fbn1 C1039G/+ valves. Conclusions: Our results show that macrophage infiltration is critical for progressive MVD. Moreover, CCR2 inhibition ameliorates MVD progression by preventing immune response. Thus, the CCR2 inhibitor RS504393 is a potential pharmacological candidate to treat MVD in MFS.

scholarly journals Tissue-resident macrophages promote extracellular matrix homeostasis in the mammary gland stroma of nulliparous mice

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ying Wang ◽  
Thomas S Chaffee ◽  
Rebecca S LaRue ◽  
Danielle N Huggins ◽  
Patrice M Witschen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mammary Gland ◽  
Mammary Gland Development ◽  
Close Association ◽  
Transcriptional Profiling ◽  
Ecm Remodeling ◽  
Macrophage Depletion ◽  
Single Cell Rna Sequencing ◽  
Gland Development ◽  
Ductal Development

Tissue-resident macrophages in the mammary gland are found in close association with epithelial structures and within the adipose stroma, and are important for mammary gland development and tissue homeostasis. Macrophages have been linked to ductal development in the virgin mammary gland, but less is known regarding the effects of macrophages on the adipose stroma. Using transcriptional profiling and single-cell RNA sequencing approaches, we identify a distinct resident stromal macrophage subpopulation within the mouse nulliparous mammary gland that is characterized by the expression of Lyve-1, a receptor for the extracellular matrix (ECM) component hyaluronan. This subpopulation is enriched in genes associated with ECM remodeling and is specifically associated with hyaluronan-rich regions within the adipose stroma and fibrous capsule of the virgin mammary gland. Furthermore, macrophage depletion leads to enhanced accumulation of hyaluronan-associated ECM in the adipose-associated stroma, indicating that resident macrophages are important for maintaining homeostasis within the nulliparous mammary gland stroma.

Development of the inlet portion of the right ventricle in the embryonic rat heart: The basis for tricuspid valve development

1994 ◽  
Vol 239 (2) ◽  
pp. 216-223 ◽  
Author(s):  
Arnold C. G. Wenink ◽  
Bert J. Wisse ◽  
Pieter M. Groenendijk
Keyword(s):  
Right Ventricle ◽  
Tricuspid Valve ◽  
Rat Heart ◽  
Valve Development ◽  
The Right

Abstract MP235: PROX1 Contributes To Cardiac Valve Disease

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
YenChun Ho ◽  
Xin Geng ◽  
Rohan Varshney ◽  
Jang Kim ◽  
Sandeep Surbrahmanian ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heart Valves ◽  
Cardiac Valve ◽  
Valve Disease ◽  
Matrix Composition ◽  
Cardiac Valves ◽  
Aortic Valves ◽  
Mitral Valves ◽  
Valve Development ◽  
Cardiac Valve Disease

Background: Heart valves regulate the unidirectional forward flow and prevent retrograde backflow of blood during the cardiac cycle. Cardiac valve disease (CVD) is observed in approximately 2.5% of the general population and the incidence increases to ~10% in elderly people. Patients with severe CVD require surgery and effective pharmacological treatments are currently not available. PROX1 is a transcription factor that regulates the development of lymphatic, venous, and lymphovenous valves (vascular valves). We identified that PROX1 is also expressed in a subset of valvular endothelial cells (VECs) that are located on the downstream (fibrosa) side of cardiac valves. Whether PROX1 regulates cardiac valve development and disease is not known. Method and Results: We have discovered that mice lacking Prox1 in their VECs ( Prox1 ΔVEC ) develop enlarged aortic and mitral valves in which the expression of proteoglycans is increased (control, N=10; Prox1 ΔVEC , N=9, p <0.05). Echocardiography revealed moderate to severe stenosis of aortic valves of Prox1 ΔVEC mice (control, N=5; Prox1 ΔVEC , N=9, p <0.05). PROX1 regulates the expression of the transcription factor FOXC2 in the vascular valves. Similarly, we have found that the expression of FOXC2 is downregulated in the VECs of Prox1 ΔVEC mice. Specific knockdown of FOXC2 in VECs results in the thickening of aortic valves (control, N=10; shFoxc2 ΔVEC , N=8, p <0.05). Furthermore, restoration of FOXC2 expression in VECs ( Foxc2 OE-VEC ) ameliorates the thickening of the aortic valves of Prox1 ΔVEC mice ( Prox1 ΔVEC , N=9; Foxc2 OE-VEC ; Prox1 ΔVEC , N=8, p <0.05). We have also determined that the expression of platelet-derived growth factor-B ( Pdgfb ) is increased in the valve tissue of Prox1 ΔVEC mice and in PROX1 deficient sheep mitral valve VECs (MVECs) (siCtrl , N=4; siProx1 , N=4, p <0.05). Additionally, hyperactivation of PDGF-B signaling in mice results in a phenotype that is similar to Prox1 ΔVEC mice (control , N=4; Pdgfb GOF , N=3, p <0.05). Conclusion: Together these data suggest that PROX1 maintains the extracellular matrix composition of cardiac valves by regulating the expressions of FOXC2 and PDGF-B in VECs.

scholarly journals Engineering cardiac microphysiological systems to model pathological extracellular matrix remodeling

2018 ◽  
Vol 315 (4) ◽  
pp. H771-H789 ◽  
Author(s):  
Nethika R. Ariyasinghe ◽  
Davi M. Lyra-Leite ◽  
Megan L. McCain
Keyword(s):  
Cardiovascular Disease ◽  
Extracellular Matrix ◽  
Myocardial Function ◽  
Myocardial Cell ◽  
Three Dimensions ◽  
Model Systems ◽  
Matrix Remodeling ◽  
Ecm Remodeling ◽  
Microphysiological Systems

Many cardiovascular diseases are associated with pathological remodeling of the extracellular matrix (ECM) in the myocardium. ECM remodeling is a complex, multifactorial process that often contributes to declines in myocardial function and progression toward heart failure. However, the direct effects of the many forms of ECM remodeling on myocardial cell and tissue function remain elusive, in part because conventional model systems used to investigate these relationships lack robust experimental control over the ECM. To address these shortcomings, microphysiological systems are now being developed and implemented to establish direct relationships between distinct features in the ECM and myocardial function with unprecedented control and resolution in vitro. In this review, we will first highlight the most prominent characteristics of ECM remodeling in cardiovascular disease and describe how these features can be mimicked with synthetic and natural biomaterials that offer independent control over multiple ECM-related parameters, such as rigidity and composition. We will then detail innovative microfabrication techniques that enable precise regulation of cellular architecture in two and three dimensions. We will also describe new approaches for quantifying multiple aspects of myocardial function in vitro, such as contractility, action potential propagation, and metabolism. Together, these collective technologies implemented as cardiac microphysiological systems will continue to uncover important relationships between pathological ECM remodeling and myocardial cell and tissue function, leading to new fundamental insights into cardiovascular disease, improved human disease models, and novel therapeutic approaches.

scholarly journals Genome-Wide Analysis of Glucocorticoid-Responsive Transcripts in the Hypothalamic Paraventricular Region of Male Rats

Endocrinology ◽  
2018 ◽  
Vol 160 (1) ◽  
pp. 38-54 ◽  
Author(s):  
Keiichi Itoi ◽  
Ikuko Motoike ◽  
Ying Liu ◽  
Sam Clokie ◽  
Yasumasa Iwasaki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Receptor Gene ◽  
Male Rats ◽  
Regulatory Mechanisms ◽  
High Dose ◽  
Sequencing Analysis ◽  
Reverse Transcription Pcr ◽  
Genome Wide ◽  
A Genome

Abstract Glucocorticoids (GCs) are essential for stress adaptation, acting centrally and in the periphery. Corticotropin-releasing factor (CRF), a major regulator of adrenal GC synthesis, is produced in the paraventricular nucleus of the hypothalamus (PVH), which contains multiple neuroendocrine and preautonomic neurons. GCs may be involved in diverse regulatory mechanisms in the PVH, but the target genes of GCs are largely unexplored except for the CRF gene (Crh), a well-known target for GC negative feedback. Using a genome-wide RNA-sequencing analysis, we identified transcripts that changed in response to either high-dose corticosterone (Cort) exposure for 12 days (12-day high Cort), corticoid deprivation for 7 days (7-day ADX), or acute Cort administration. Among others, canonical GC target genes were upregulated prominently by 12-day high Cort. Crh was upregulated or downregulated most prominently by either 7-day ADX or 12-day high Cort, emphasizing the recognized feedback effects of GC on the hypothalamic-pituitary-adrenal (HPA) axis. Concomitant changes in vasopressin and apelin receptor gene expression are likely to contribute to HPA repression. In keeping with the pleotropic cellular actions of GCs, 7-day ADX downregulated numerous genes of a broad functional spectrum. The transcriptome response signature differed markedly between acute Cort injection and 12-day high Cort. Remarkably, six immediate early genes were upregulated 1 hour after Cort injection, which was confirmed by quantitative reverse transcription PCR and semiquantitative in situ hybridization. This study may provide a useful database for studying the regulatory mechanisms of GC-dependent gene expression and repression in the PVH.

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