isolation-conditionally-immortalized-mouse-glomerular-endothelial

Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria

Glomerular endothelial cell (GEC) dysfunction can initiate and contribute to glomerular filtration barrier breakdown. Increased mitochondrial oxidative ...

isolation-mouse-interstitial-valve-cells-to-study-calcification

Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve <em>In Vitro</em>

The calcification of aortic valve cells is the hallmark of aortic stenosis and is associated with valve cusp fibrosis. Valve interstitial cells (VICs) ...

The Icahn School of Medicine at Mount Sinai

Myocardial fibrosis is a major determinant of clinical outcomes in heart failure (HF) patients. It is characterized by the emergence of myofibroblasts and early activation of pro-fibrotic signaling pathways before adverse ventricular remodeling and progression of HF. Boron has been reported in recent years to augment the innate immune system and cell proliferation, which play an important role in the repair and regeneration of the injured tissue. Currently, the effect of boron on cardiac contractility and remodeling is unknown. In this study, we investigated, for the first time, the effect of boron supplementation on cardiac function, myocardial fibrosis, apoptosis and regeneration in a rat model myocardial infarction (MI)-induced HF. MI was induced in animals and borax, a sodium salt of boron, was administered for 7 days, p.o., 21 days post-injury at a dose level of 4 mg/kg body weight. Transthoracic echocardiographic analysis showed a significant improvement in systolic and diastolic functions with boron treatment compared to saline control. In addition, boron administration showed a marked reduction in myocardial fibrosis and apoptosis in the injured hearts, highlighting a protective effect of boron in the ischemic heart. Interestingly, we observed a tenfold increase of nuclei in thin myocardial sections stained positive for the cell cycle marker Ki67 in the MI boron-treated rats compared to saline, indicative of increased cardiomyocyte cell cycle activity in MI hearts, highlighting its potential role in regeneration post-injury. We similarly observed increased Ki67 and BrdU staining in cultured fresh neonatal rat ventricular cardiomyocytes. Collectively, the results show that boron positively impacted MI-induced HF and attenuated cardiac fibrosis and apoptosis, two prominent features of HF. Importantly, boron has the potential to induce cardiomyocyte cell cycle entry and potentially cardiac tissue regeneration after injury. Boron might be beneficial as a supplement in MI and may be a good candidate substance for anti-fibrosis approach.

Boron improves cardiac contractility and fibrotic remodeling following myocardial infarction injury.

Cardiac fibrosis is characterized by excessive deposition of extracellular matrix proteins and myofibroblast differentiation. Our previous findings have implicated resistin in cardiac fibrosis; however, the molecular mechanisms underlying this process are still unclear. Here we investigated the role of resistin in fibroblast-to-myofibroblast differentiation and elucidated the pathways involved in this process. Fibroblast-to-myofibroblast transdifferentiation was induced with resistin or TGFβ1 in NIH-3T3 and adult cardiac fibroblasts. mRNA and protein expression of fibrotic markers were analyzed by qPCR and immunoblotting. Resistin-knockout mice, challenged with a high-fat diet (HFD) for 20 weeks to stimulate cardiac impairment, were analyzed for cardiac function and fibrosis using histologic and molecular methods. Cardiac fibroblasts stimulated with resistin displayed increased fibroblast-to-myofibroblast conversion, with increased levels of αSma, col1a1, Fn, Ccn2 and Mmp9, with remarkable differences in the actin network appearance. Mechanistically, resistin promotes fibroblast-to-myofibroblast transdifferentiation and fibrogenesis via JAK2/STAT3 and JNK/c-Jun signaling pathways, independent of TGFβ1. Resistin-null mice challenged with HFD showed an improvement in cardiac function and a decrease in tissue fibrosis and reduced mRNA levels of fibrogenic markers. These findings are the first to delineate the role of resistin in the process of cardiac fibroblast-to-myofibroblast differentiation via JAK/STAT3 and JNK/c-Jun pathways, potentially leading to stimulation of cardiac fibrosis.

Resistin induces cardiac fibroblast-myofibroblast differentiation through JAK/STAT3 and JNK/c-Jun signaling.

This study analyzed the expression of extracellular matrix (ECM) proteins during aortic valve calcification with mass spectrometry, and further validated in an independent human cohort using RNAseq data. The study reveals that valve calcification is associated with significant disruption in ECM and metabolic pathways, and highlights a strong connection between metabolic markers and ECM remodeling. It also identifies FNDC1 and MXRA5 as novel ECM biomarkers in calcified valves, electing them as potential targets in the development and progression of aortic stenosis.

Proteomic Architecture of Valvular Extracellular Matrix: FNDC1 and MXRA5 Are New Biomarkers of Aortic Stenosis.

Increased resistin (Retn) levels are associated with development of cardiovascular diseases. However, the role of Retn in heart failure (HF) is still unclear. Here we probed the functional and molecular mechanism underlying the beneficial effect of Retn deletion in HF.

Resistin deletion protects against heart failure injury by targeting DNA damage response.

Aortic stenosis (AS) is the most common heart valve disease requiring surgery in developed countries, with a rising global burden associated with aging populations. The predominant cause of AS is believed to be driven by calcific degeneration of the aortic valve and a growing body of evidence suggests that platelets play a major role in this disease pathophysiology. Furthermore, platelets are a player in bioprosthetic valve dysfunction caused by their role in leaflet thrombosis and thickening. This review presents the molecular function of platelets in the context of recent and rapidly evolving understanding the role of platelets in AS, both of the native aortic valve and bioprosthetic valves, where there remain concerns about the effects of subclinical leaflet thrombosis on long-term prosthesis durability. This review also presents the role of antiplatelet and anticoagulation therapies on modulating the impact of platelets on native and bioprosthetic aortic valves, highlighting the need for further studies to determine whether these therapies are protective and may increase the life span of surgical and transcatheter aortic valve implants. By linking molecular mechanisms through which platelets drive disease of native and bioprosthetic aortic valves with studies evaluating the clinical impact of antiplatelet and antithrombotic therapies, we aim to bridge the gaps between our basic science understanding of platelet biology and their role in patients with AS and ensuing preventive and therapeutic implications.

Platelets: Implications in Aortic Valve Stenosis and Bioprosthetic Valve Dysfunction From Pathophysiology to Clinical Care.

Calcific Aortic Valve Disease (CAVD) is a fibrocalcific disease. Lipoproteins and oxidized phospholipids play a substantial role in CAVD; the level of Lp(a) has been shown to accelerate the progression of valve calcification. Indeed, oxidized phospholipids carried by Lp(a) into the aortic valve stimulate endothelial dysfunction and promote inflammation. Inflammation and growth factors actively promote the synthesis of the extracellular matrix (ECM) and trigger an osteogenic program. The accumulation of ECM proteins promotes lipid adhesion to valve tissue, which could initiate the osteogenic program in interstitial valve cells. Statin treatment has been shown to have the ability to diminish the death rate in subjects with atherosclerotic impediments by decreasing the serum LDL cholesterol levels. However, the use of HMG-CoA inhibitors (statins) as cholesterol-lowering therapy did not significantly reduce the progression or the severity of aortic valve calcification. However, new clinical trials targeting Lp(a) or PCSK9 are showing promising results in reducing the severity of aortic stenosis. In this review, we discuss the implication of lipids in aortic valve calcification and the current findings on the effect of lipid-lowering therapy in aortic stenosis.

Rihab Bouchareb

Cardiovascular Research Center,
Department of Medicine,
Division of Nephrology,
Department of Medicine, Division of Nephrology

The Icahn School of Medicine at Mount Sinai

Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria

Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve In Vitro

Rihab Bouchareb

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Cardiovascular Research Center,Department of Medicine,Division of Nephrology,Department of Medicine, Division of Nephrology

The Icahn School of Medicine at Mount Sinai

Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria

Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve In Vitro

Cardiovascular Research Center,
Department of Medicine,
Division of Nephrology,
Department of Medicine, Division of Nephrology