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

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.

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanyan Zhu ◽  
Yumeng Huang ◽  
Qian Ji ◽  
Shengqiao Fu ◽  
Jia Gu ◽  
...  

The extracellular matrix (ECM) is a highly dynamic and complex network structure, which exists in almost all tissues and is the microenvironment that cells rely on for survival. ECM interacts with cells to regulate diverse functions, including differentiation, proliferation, and migration. Neutrophils are the most abundant immune cells in circulation and play key roles in orchestrating a complex series of events during inflammation. Neutrophils can also mediate ECM remodeling by providing specific matrix-remodeling enzymes (such as neutrophil elastase and metalloproteinases), generating neutrophil extracellular traps, and releasing exosomes. In turn, ECM can remodel the inflammatory microenvironment by regulating the function of neutrophils, which drives disease progression. Both the presence of ECM and the interplay between neutrophils and their extracellular matrices are considered an important and outstanding mechanistic aspect of inflammation. In this review, the importance of ECM will be considered, together with the discussion of recent advances in understanding the underlying mechanisms of the intricate interplay between ECM and neutrophils. A better comprehension of immune cell-matrix reciprocal dependence has exciting implications for the development of new therapeutic options for neutrophil-associated infectious and inflammatory diseases.


2018 ◽  
Vol 315 (4) ◽  
pp. H771-H789 ◽  
Author(s):  
Nethika R. Ariyasinghe ◽  
Davi M. Lyra-Leite ◽  
Megan L. McCain

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.


2022 ◽  
Author(s):  
Shun Yan ◽  
Yin Peng ◽  
Jin Lu ◽  
Saima Shakil ◽  
Yang Shi ◽  
...  

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.


Author(s):  
Zeng Wang ◽  
Xiaolin Ding ◽  
Feifei Cao ◽  
Xishan Zhang ◽  
Jingguo Wu

The etiology of lumbocrural pain is tightly concerned with intervertebral disk degeneration (IDD). Bone mesenchymal stem cell (BMSC)-based therapy bears potentials for IDD treatment. The properties of microRNA (miRNA)-modified BMSCs may be altered. This study investigated the role and mechanism of BMSCs promoting extracellular matrix (ECM) remodeling of degenerated nucleus pulposus cells (NPCs) via the miR-101-3p/EIF4G2 axis. NPCs were collected from patients with IDD and lumbar vertebral fracture (LVF). The expressions of miR-101-3p and ECM-related proteins, Collagen-I (Col-I) and Collagen-II (Col-II), were detected using the reverse transcription-quantitative polymerase chain reaction. The expressions of Col-I and Col-II, major non-collagenous component Aggrecan, and major catabolic factor Matrix metalloproteinase-13 (MMP-13) were detected using Western blotting. BMSCs were cocultured with degenerated NPCs from patients with IDD. Viability and apoptosis of NPCs were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. After the degenerated NPCs were transfected with the miR-101-3p inhibitor, the expressions of ECM-related proteins, cell viability, and apoptosis were detected. The targeting relationship between miR-101-3p and EIF4G2 was verified. Functional rescue experiments verified the effects of miR-101-3p and EIF4G2 on ECM remodeling of NPCs. Compared with the NPCs of patients with LVF, the degenerated NPCs of patients with IDD showed downregulated miR-101-3p, Col-II, and Aggrecan expressions and upregulated MMP-13 and Col-I expressions. BMSCs increased the expressions of miR-101-3p, Aggrecan, and Col-II, and decreased the expressions of MMP-13 and Col-I in degenerated NPCs. BMSCs enhanced NPC viability and repressed apoptosis. Downregulation of miR-101-3p suppressed the promoting effect of BMSCs on ECM remodeling. miR-101-3p targeted EIF4G2. Downregulation of EIF4G2 reversed the inhibiting effect of the miR-101-3p inhibitor on ECM remodeling. In conclusion, BMSCs increased the miR-101-3p expression in degenerated NPCs to target EIF4G2, thus promoting the ECM remodeling of NPCs.


ESC CardioMed ◽  
2018 ◽  
pp. 713-715
Author(s):  
Dorien Schepers ◽  
Bart Loeys

Marfan syndrome is an autosomal dominant, multisystemic disorder, presenting with skeletal, ocular, and cardiovascular symptoms. This connective tissue disease is caused by mutations in FBN1, encoding fibrillin-1, which is an important extracellular matrix protein. Marfan syndrome shows significant clinical overlap with Loeys–Dietz syndrome, which is caused by genetic defects in components of the transforming growth factor-beta pathway: TGFBR1, TGFBR2, TGFB2, TGFB3, SMAD2, and SMAD3. Overlapping clinical features between Marfan syndrome and Loeys–Dietz syndrome include aortic root aneurysm, arachnodactyly, scoliosis, and pectus deformity.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Cheri L. Lamb ◽  
Giovan N. Cholico ◽  
Daniel E. Perkins ◽  
Michael T. Fewkes ◽  
Julia Thom Oxford ◽  
...  

The aryl hydrocarbon receptor (AhR) is a soluble, ligand-activated transcription factor that mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Increasing evidence implicates the AhR in regulating extracellular matrix (ECM) homeostasis. We recently reported that TCDD increased necroinflammation and myofibroblast activation during liver injury elicited by carbon tetrachloride (CCl4). However, TCDD did not increase collagen deposition or exacerbate fibrosis in CCl4-treated mice, which raises the possibility that TCDD may enhance ECM turnover. The goal of this study was to determine how TCDD impacts ECM remodeling gene expression in the liver. Male C57BL/6 mice were treated for 8 weeks with 0.5 mL/kg CCl4, and TCDD (20 μg/kg) was administered during the last two weeks. Results indicate that TCDD increased mRNA levels of procollagen types I, III, IV, and VI and the collagen processing molecules HSP47 and lysyl oxidase. TCDD also increased gelatinase activity and mRNA levels of matrix metalloproteinase- (MMP-) 3, MMP-8, MMP-9, and MMP-13. Furthermore, TCDD modulated expression of genes in the plasminogen activator/plasmin system, which regulates MMP activation, and it also increased TIMP1 gene expression. These findings support the notion that AhR activation by TCDD dysregulates ECM remodeling gene expression and may facilitate ECM metabolism despite increased liver injury.


2018 ◽  
Author(s):  
Hyun-Taek Kim ◽  
Wenguang Yin ◽  
Young-June Jin ◽  
Paolo Panza ◽  
Felix Gunawan ◽  
...  

AbstractImpaired alveolar formation and maintenance are features of many pulmonary diseases that are associated with significant morbidity and mortality. In a forward genetic screen for modulators of mouse lung development, we identified the non-muscle myosin II heavy chain gene, Myh10. Myh10 mutant pups exhibit cyanosis and respiratory distress, and die shortly after birth from differentiation defects in alveolar epithelium and mesenchyme. From omics analyses and follow up studies, we find decreased Thrombospondin expression accompanied with increased matrix metalloproteinase activity in both mutant lungs and cultured mutant fibroblasts, as well as disrupted extracellular matrix (ECM) remodeling. Loss of Myh10 specifically in mesenchymal cells results in ECM deposition defects and alveolar simplification. Notably, MYH10 expression is down-regulated in the lung of emphysema patients. Altogether, our findings reveal critical roles for Myh10 in alveologenesis at least in part via the regulation of ECM remodeling, which may contribute to the pathogenesis of emphysema.


2020 ◽  
Author(s):  
Tal M. Dankovich ◽  
Rahul Kaushik ◽  
Gabriel Cassinelli Petersen ◽  
Philipp Emanuel Giro ◽  
Hannah Abdul Hadi ◽  
...  

SummaryThe brain extracellular matrix (ECM) assembles around neurons and synapses, and is thought to change only rarely, through proteolysis and renewed protein synthesis. We report here an alternative ECM remodeling mechanism, based on the recycling of ECM molecules. We found that a key ECM protein, Tenascin-R, is frequently endocytosed, and later resurfaces, preferentially near synapses. The TNR molecules complete this cycle within ∼3 days, in an activity-dependent fashion.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
John J Parent ◽  
Jeffrey A Towbin ◽  
John L Jefferies

Introduction: Left ventricular non-compaction cardiomyopathy (LVNC) is a rare and unique cardiomyopathy. Its presentation can range from a benign phenotype to overt heart failure and sudden cardiac death. The genetics of LVNC are not completely understood and current genetic testing has a yield of about 30% in identifying a causative gene mutation. We present a series of patients with LVNC and fibrillin-1 (FBN1) gene mutations. Hypothesis: We hypothesize that FBN1 gene mutations can lead to LVNC by way of its role in the myocardial extracellular matrix during cardiac development. Methods: A retrospective review of all patients with LVNC at our institution was performed for purposes of another investigation. The process unexpectedly identified patients with LVNC and FBN1 gene mutations, as well as LVNC and Marfan syndrome. Results: Approximately 150 patients are followed in our clinic with LVNC. We screened this population and found 51 patients on medical therapy for reduced function. We retrospectively reviewed gene testing in these 51 patients, when available, and identified 5 patients (10%) with an FBN1 gene mutation. All 5 patients had a dilated LVNC phenotype and previous or current evidence of left ventricular dysfunction. Syndrome breakdown as follows: 3 with Marfan, 1 with Shprintzen-Goldberg, and 1 with no identifiable syndrome. Dilated cardiomyopathy/LVNC gene testing was performed in 3 patients; 2 had disease causing myosin heavy chain 7 gene defects and 1 had no defects. Conclusions: The role of FBN1 in the human myocardium is not completely understood but it is expressed in the developing fetal heart and is a component of the myocardial extracellular matrix. Although causation has not been proven by our report, it certainly raises interest in a mechanistic relationship between LVNC and FBN1 given the increased prevalence of Marfan syndrome and probable increased prevalence of FBN1 gene mutations in this cohort of LVNC patients in light of FBN1.


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