Abstract P140: Mutant Mice Carrying Global Loss Of Npr1 Exhibit Cardiac Fibrosis, Hypertrophy, And Congestive Heart Failure: Implication Of TGF-Beta/SMAD Signaling Pathway

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Chandramohan Ramasamy ◽  
Umadevi Subramanian ◽  
Kailash N Pandey
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Growth Factor ◽  
Cardiac Hypertrophy ◽  
Signaling Pathway ◽  
Cardiac Fibrosis ◽  
Left Ventricular ◽  
Mutant Mice ◽  
Null Mutant ◽  
Wild Type

The cardiac hormones, atrial and brain natriuretic peptides (ANP and BNP) bind to natriuretic peptide receptor-A (NPRA), which synthesizes the second messenger cGMP. The objective of this study was to determine the underlying mechanisms that regulate the development of cardiac hypertrophy, fibrosis, and congestive heart failure (CHF) in Npr1 (encoding NPRA) gene-knockout mice. The Npr1 null mutant ( Npr1 -/- , 0-copy), heterozygous ( Npr1 +/- , 1-copy), and wild-type ( Npr1 +/+ , 2-copy) mice were orally administered with transforming growth factor-β1 receptor I (TGF-β1R1) antagonist, GW788388 (2 mg/kg/day) by oral gavage for 28 days. The left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVEDS), posterior wall thickness (PWT), and percent fractional shortening (FS) were analyzed by echocardiography. The heart was isolated and used for the analysis of fibrotic markers using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot methods. The heart weight-to-body weight (HW/BW) ratio, LVEDD, LVEDS and PWT were significantly (p<0.005) increased in Npr1 -/- and Npr1 +/- mice than wild-type Npr1 +/+ mice. The FS was greatly reduced in Npr1 -/- and Npr1 +/- mice compared with Npr1 +/+ mice. The Npr1 -/- null mutant (0-copy) mice showed 52% increase in HW/BW ratio and 6-fold induction of cardiac fibrosis as compared with 2-copy control mice. The cardiac expression of fibrotic markers including collagen-1a (COL-1a; 3.5-fold), connective tissue growth factor (CTGF; 5-fold), α-smooth muscle actin (α-SMA; 4-fold), TGF-β1RI (4-fold), TGF-β1RII (3.5-fold), and SMAD-2/3 proteins (3-to-5 fold) were significantly increased in Npr1 -/- and Npr1 +/- mutant mice compared with age-matched Npr1 +/+ animals. The treatment with TGF-β1R1 antagonist, significantly (p<0.001) prevented the cardiac hypertrophy, fibrosis, CHF, and down-regulated the expression of fibrotic markers and SMAD proteins in mutant mice. The LVEDD, LVEDS, and FS were significantly (p<0.001) improved in the drug treated Npr1 -/- mice. The present results indicate that the cardiac hypertrophy, fibrosis, and CHF in Npr1 mutant mice is regulated through the TGF-β1-mediated SMAD-dependent signaling pathway.

Abstract 78: Transforming Growth Factor-β Induces the Cardiac Fibrosis and Remodeling in Guanylyl cyclase/Natriuretic Peptide Receptor-A Gene-Disrupted Null Mutant Mice

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Kailash N Pandey ◽  
Umadevi Subramanian
Keyword(s):  
Growth Factor ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Left Ventricular ◽  
Null Mutant ◽  
Wild Type ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A ◽  
Β Receptor ◽  
Null Mutant Mice

Genetic disruption of guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene (Npr1) in mice exhibits high blood pressure, cardiac hypertrophy, fibrosis, and remodeling leading to congestive heart failure. The objective of this study was to determine the mechanisms regulating the development of fibrosis in Npr1 gene-disrupted mice hearts. The Npr1 null mutant (Npr1-/-, 0-copy), heterozygous (Npr1+/-, 1-copy), and wild-type (Npr1+/+, 2-copy) mice were administered by oral gavage with transforming growth factor-β1 (TGF- β1) receptor inhibitor GW788388 (1mg/kg/day) for 28 days. The heart tissues were isolated and used for quantification of fibrotic markers by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot analyses. Together, systolic blood pressure (SBP), heart weight-to-body weight (HW/BW) ratio, left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVEDS), and percent fractional shortening (FS) were analyzed. The Npr1-/- null mutant mice hearts displayed 6-fold induction of fibrosis compared with wild-type (WT) Npr1+/+ mice. Furthermore, the increased expression of fibrotic markers as observed, including connective tissue growth factor (CTGF, 5-fold), α-smooth muscle actin (α-SMA, 4-fold) and TGF-β receptor I (TGF-βRI, 4-fold), TGF-β receptor II (TGF-βRII, 3.5-fold) and Smad2/3 proteins in Npr1-/- mice hearts compared with WT control mice. However, treatment with TGF-β receptor antagonist, GW788388, significantly prevented the cardiac fibrosis and down-regulated the expression of fibrotic markers and Smad proteins in Npr1-/- mice compared to vehicle-treated WT controls. The results of the present study suggest that the activation of cardiac fibrosis in Npr1-/- mice is mainly triggered through TGF-β mediated Smad-dependent pathways.

scholarly journals Inhibition of the canonical Wnt signaling pathway by a β-catenin/CBP inhibitor prevents heart failure by ameliorating cardiac hypertrophy and fibrosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thanachai Methatham ◽  
Shota Tomida ◽  
Natsuka Kimura ◽  
Yasushi Imai ◽  
Kenichi Aizawa
Keyword(s):  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Left Ventricular ◽  
Cardiac Wall ◽  
Macrophage Marker ◽  
Glycolysis Pathway ◽  
Canonical Wnt ◽  
Macrophage Accumulation

AbstractIn heart failure (HF) caused by hypertension, the myocyte size increases, and the cardiac wall thickens. A low-molecular-weight compound called ICG001 impedes β-catenin-mediated gene transcription, thereby protecting both the heart and kidney. However, the HF-preventive mechanisms of ICG001 remain unclear. Hence, we investigated how ICG001 can prevent cardiac hypertrophy and fibrosis induced by transverse aortic constriction (TAC). Four weeks after TAC, ICG001 attenuated cardiac hypertrophy and fibrosis in the left ventricular wall. The TAC mice treated with ICG001 showed a decrease in the following: mRNA expression of brain natriuretic peptide (Bnp), Klf5, fibronectin, β-MHC, and β-catenin, number of cells expressing the macrophage marker CD68 shown in immunohistochemistry, and macrophage accumulation shown in flow cytometry. Moreover, ICG001 may mediate the substrates in the glycolysis pathway and the distinct alteration of oxidative stress during cardiac hypertrophy and HF. In conclusion, ICG001 is a potential drug that may prevent cardiac hypertrophy and fibrosis by regulating KLF5, immune activation, and the Wnt/β-catenin signaling pathway and inhibiting the inflammatory response involving macrophages.

Myeloid-Derived Growth Factor Protects Against Pressure Overload-Induced Heart Failure by Preserving Sarco/Endoplasmic Reticulum Ca 2+ -ATPase Expression in Cardiomyocytes

Circulation ◽  
2021 ◽  
Author(s):  
Mortimer Korf-Klingebiel ◽  
Marc R. Reboll ◽  
Felix Polten ◽  
Natalie Weber ◽  
Felix Jäckle ◽  
...  
Keyword(s):  
Heart Failure ◽  
Bone Marrow ◽  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Plasma Concentrations ◽  
Pressure Overload ◽  
Inflammatory Cells ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Wild Type

Background: Inflammation contributes to the pathogenesis of heart failure, but there is limited understanding of inflammation's potential benefits. Inflammatory cells secrete myeloid-derived growth factor (MYDGF) to promote tissue repair after acute myocardial infarction. We hypothesized that MYDGF has a role in cardiac adaptation to persistent pressure overload. Methods: We defined the cellular sources and function of MYDGF in wild-type, Mydgf -deficient ( Mydgf -/- ), and Mydgf bone marrow-chimeric or bone marrow-conditional transgenic mice with pressure overload-induced heart failure after transverse aortic constriction surgery. We measured MYDGF plasma concentrations by targeted liquid chromatography-mass spectrometry. We identified MYDGF signaling targets by phosphoproteomics and substrate-based kinase activity inference. We recorded Ca 2+ transients and sarcomere contractions in isolated cardiomyocytes. Additionally, we explored the therapeutic potential of recombinant MYDGF. Results: MYDGF protein abundance increased in the left ventricular (LV) myocardium and in blood plasma of pressure-overloaded mice. Patients with severe aortic stenosis also had elevated MYDGF plasma concentrations, which declined after transcatheter aortic valve implantation. Monocytes and macrophages emerged as the main MYDGF sources in the pressure-overloaded murine heart. While Mydgf -/- mice had no apparent phenotype at baseline, they developed more severe LV hypertrophy and contractile dysfunction during pressure overload than wild-type mice. Conversely, conditional transgenic overexpression of MYDGF in bone marrow-derived inflammatory cells attenuated pressure overload-induced hypertrophy and dysfunction. Mechanistically, MYDGF inhibited G protein coupled receptor agonist-induced hypertrophy and augmented sarco/endoplasmic reticulum Ca 2+ ATPase 2a (SERCA2a) expression in cultured neonatal rat cardiomyocytes by enhancing PIM1 serine/threonine kinase expression and activity. Along this line, cardiomyocytes from pressure-overloaded Mydgf -/- mice displayed reduced PIM1 and SERCA2a expression, greater hypertrophy, and impaired Ca 2+ cycling and sarcomere function compared to cardiomyocytes from pressure-overloaded wild-type mice. Transplanting Mydgf -/- mice with wild-type bone marrow cells augmented cardiac PIM1 and SERCA2a levels and ameliorated pressure overload-induced hypertrophy and dysfunction. Pressure-overloaded Mydgf -/- mice were similarly rescued by adenoviral Serca2a gene transfer. Treating pressure-overloaded wild-type mice subcutaneously with recombinant MYDGF enhanced SERCA2a expression, attenuated LV hypertrophy and dysfunction, and improved survival. Conclusions: These findings establish a MYDGF-based adaptive crosstalk between inflammatory cells and cardiomyocytes that protects against pressure overload-induced heart failure.

scholarly journals Loss of Endothelial HIF-Prolyl hydroxylase 2 (PHD2) Induces Cardiac Hypertrophy and Fibrosis

2021 ◽  
Author(s):  
Zhiyu Dai ◽  
Jianding Cheng ◽  
Bin Liu ◽  
Dan Yi ◽  
Anlin Feng ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Cardiac Fibrosis ◽  
Left Ventricular ◽  
Dependent Manner ◽  
Adaptive Responses ◽  
Genetic Ablation ◽  
Pathological Cardiac Hypertrophy ◽  
And Function

Cardiac hypertrophy and fibrosis are common adaptive responses to injury and stress, eventually leading to heart failure. Hypoxia signaling is important to the (patho)physiological process of cardiac remodeling. However, the role of endothelial Prolyl-4 hydroxylase 2 (PHD2)/hypoxia inducible factors (HIFs) signaling in the pathogenesis of heart failure remains elusive. We observed a marked decrease of PHD2 expression in heart tissues and cardiovascular endothelial cells from patients with cardiomyopathy. Mice with Tie2-Cre-mediated deletion of Egln1 (encoding PHD2) or tamoxifen-induced endothelial Egln1 deletion exhibited left ventricular hypertrophy and cardiac fibrosis. Genetic ablation and pharmacological inhibition of Hif2a but not Hif1a in endothelial Egln1 deficient mice normalized cardiac size and function. The present studies define for the first time an unexpected role of endothelial PHD2 deficiency in inducing cardiac hypertrophy and fibrosis in a HIF-2α dependent manner. Targeting PHD2/HIF-2α signaling may represent a novel therapeutic approach for the treatment of pathological cardiac hypertrophy and failure.

scholarly journals CCR2 mediates the uptake of bone marrow-derived fibroblast precursors in angiotensin II-induced cardiac fibrosis

2011 ◽  
Vol 301 (2) ◽  
pp. H538-H547 ◽  
Author(s):  
Jing Xu ◽  
Song-Chang Lin ◽  
Jiyuan Chen ◽  
Yuanxin Miao ◽  
George E. Taffet ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Angiotensin Ii ◽  
Cardiac Hypertrophy ◽  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Systolic Function ◽  
Left Ventricular ◽  
Collagen I ◽  
Wild Type

Angiotensin II plays an important role in the development of cardiac hypertrophy and fibrosis, but the underlying cellular and molecular mechanisms are not completely understood. Recent studies have shown that bone marrow-derived fibroblast precursors are involved in the pathogenesis of cardiac fibrosis. Since bone marrow-derived fibroblast precursors express chemokine receptor, CCR2, we tested the hypothesis that CCR2 mediates the recruitment of fibroblast precursors into the heart, causing angiotensin II-induced cardiac fibrosis. Wild-type and CCR2 knockout mice were infused with angiotensin II at 1,500 ng·kg−1·min−1. Angiotensin II treatment resulted in elevated blood pressure and cardiac hypertrophy that were not significantly different between wild-type and CCR2 knockout mice. Angiotensin II treatment of wild-type mice caused prominent cardiac fibrosis and accumulation of bone marrow-derived fibroblast precursors expressing the hematopoietic markers, CD34 and CD45, and the mesenchymal marker, collagen I. However, angiotensin II-induced cardiac fibrosis and accumulation of bone marrow-derived fibroblast precursors in the heart were abrogated in CCR2 knockout mice. Furthermore, angiotensin II treatment of wild-type mice increased the levels of collagen I, fibronectin, and α-smooth muscle actin in the heart, whereas these changes were not observed in the heart of angiotensin II-treated CCR2 knockout mice. Functional studies revealed that the reduction of cardiac fibrosis led to an impairment of cardiac systolic function and left ventricular dilatation in angiotensin II-treated CCR2 knockout mice. Our data demonstrate that CCR2 plays a pivotal role in the pathogenesis of angiotensin II-induced cardiac fibrosis through regulation of bone marrow-derived fibroblast precursors.

scholarly journals Telmisartan ameliorates cardiac fibrosis and diastolic function in cardiorenal heart failure with preserved ejection fraction

2021 ◽  
pp. 153537022110350
Author(s):  
Di Chang ◽  
Ting-Ting Xu ◽  
Shi-Jun Zhang ◽  
Yu Cai ◽  
Shu-Dan Min ◽  
...  
Keyword(s):  
Heart Failure ◽  
Growth Factor ◽  
Ejection Fraction ◽  
Diastolic Function ◽  
Rat Model ◽  
Cardiac Fibrosis ◽  
Left Ventricular ◽  
Male Rats ◽  
Preserved Ejection Fraction ◽  
Collagen Iii

Chronic kidney disease (CKD) is a major contributor to the development of heart failure with preserved ejection fraction (HFpEF), whereas the underlying mechanism of cardiorenal HFpEF is still elusive. The aim of this study was to investigate the role of cardiac fibrosis in a rat model of cardiorenal HFpEF and explore whether treatment with Telmisartan, an inhibitor of renin-angiotensin-aldosterone system (RAAS), can ameliorate cardiac fibrosis and preserve diastolic function in cardiorenal HFpEF. Male rats were subjected to 5/6 subtotal nephrectomy (SNX) or sham operation (Sham), and rats were allowed four weeks to recover and form a stable condition of CKD. Telmisartan or vehicle was then administered p.o. (8 mg/kg/d) for 12 weeks. Blood pressure, brain natriuretic peptide (BNP), echocardiography, and cardiac magnetic resonance imaging were acquired to evaluate cardiac structural and functional alterations. Histopathological staining, real-time polymerase chain reaction (PCR) and western blot were performed to evaluate cardiac remodeling. SNX rats showed an HFpEF phenotype with increased BNP, decreased early to late diastolic transmitral flow velocity (E/A) ratio, increased left ventricular (LV) hypertrophy and preserved ejection fraction (EF). Pathology revealed increased cardiac fibrosis in cardiorenal HFpEF rats compared with the Sham group, while chronic treatment with Telmisartan significantly decreased cardiac fibrosis, accompanied by reduced markers of fibrosis (collagen I and collagen III) and profibrotic cytokines (α-smooth muscle actin, transforming growth factor-β1, and connective tissue growth factor). In addition, myocardial inflammation was decreased after Telmisartan treatment, which was in a linear correlation with cardiac fibrosis. Telmisartan also reversed LV hypertrophy and E/A ratio, indicating that Telmisartan can improve LV remodeling and diastolic function in cardiorenal HFpEF. In conclusion, cardiac fibrosis is central to the pathology of cardiorenal HFpEF, and RAAS modulation with Telmisartan is capable of alleviating cardiac fibrosis and preserving diastolic dysfunction in this rat model.

Activation of SIRT1 by Resveratrol Alleviates Pressure Overload-Induced Cardiac Hypertrophy via Suppression of TGF-β1 Signaling

Pharmacology ◽  
2021 ◽  
pp. 1-15
Author(s):  
Yong Chen ◽  
Ting He ◽  
Zhongjun Zhang ◽  
Junzhi Zhang
Keyword(s):  
Cardiac Hypertrophy ◽  
Protective Effect ◽  
Signaling Pathway ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Ang Ii ◽  
Tgf Β1

<b><i>Introduction:</i></b> Silent information regulator 1 (SIRT1) has been extensively investigated in the cardiovascular system and has been shown to play a pivotal role in mediating cell death/survival, energy production, and oxidative stress. However, the functional role of SIRT1 in pressure overload-induced cardiac hypertrophy and dysfunction remains unclear. Resveratrol (Rsv), a widely used activator of SIRT1, has been reported to protect against cardiovascular disease. We here examine whether activation of SIRT1 by Rsv attenuate pressure overload-induced cardiac hypertrophy and to identify the underlying molecular mechanisms. <b><i>Methods:</i></b> In vivo, rat model of pressure overload-induced myocardial hypertrophy was established by abdominal aorta constriction (AAC) procedure. In vitro, Angiotensin II (Ang II) was applied to induce hypertrophy in cultured neonatal rat cardiomyocytes (NCMs). Hemodynamics and histological analyses of the heart were evaluated. The expression of SIRT1, transforming growth factor-β1 (TGF-β1)/phosphorylated (p)-small mother against decapentaplegic (Smad)3 and hypertrophic markers were determined by immunofluorescence, real-time PCR, and Western blotting techniques. <b><i>Results:</i></b> In the current study, Rsv treatment improved left ventricular function and reduced left ventricular hypertrophy and cardiac fibrosis significantly in the pressure overload rats. The expression of SIRT1 was significantly reduced, while the expression of TGF-β1/p-Smad3 was significantly enhanced in AAC afflicted rat heart. Strikingly, treatment with Rsv restored the expressions of SIRT1 and TGF-β1/p-Smad3 under AAC influence. However, SIRT1 inhibitor Sirtinol (Snl) markedly prevented the effects of Rsv, which suggest that SIRT1 signaling pathway was involved in the cardiac protective effect of Rsv. In vitro studies performed in Ang II-induced hypertrophy in NCMs confirmed the cardiac protective effect of Rsv. Furthermore, the study presented that SIRT1 negatively correlated with the cardiac hypertrophy, cardiac fibrosis, and the TGF-β1/p-Smad3 expression. <b><i>Conclusions:</i></b> Taken together, these results indicated that activation of SIRT1 by Rsv attenuates cardiac hypertrophy, cardiac fibrosis, and improves cardiac function possibly via regulation of the TGF-β1/p-Smad3 signaling pathway. Our study may provide a potential therapeutic strategy for cardiac hypertrophy.

Abstract 1224: Rock1 Deletion Prevents Cardiac Dilation And Improves Contractile Function In Pathological Cardiac Hypertrophy

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Jianjian Shi ◽  
Yi-Wei Zhang ◽  
Gerald W Dorn ◽  
Lei Wei
Keyword(s):  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Cardiac Fibrosis ◽  
Contractile Function ◽  
Left Ventricular ◽  
Cardiomyocyte Hypertrophy ◽  
Molecular Defect ◽  
Contractile Dysfunction ◽  
Adrenergic Stimulation ◽  
Compensatory Response

The development of left ventricular cardiomyocyte hypertrophy in response to increased hemodynamic load and neurohormonal stress is initially a compensatory response. However, persistent stress eventually leads to dilated heart failure, which is a common cause of heart failure in human hypertensive and valvular heart disease. We have recently reported that ROCK1 homozygous knockout mice exhibited reduced cardiac fibrosis and cardiomyocyte apoptosis, while displayed a preserved compensatory hypertrophic response to pressure overload. Here, we tested effects of ROCK1 deficiency on cardiac hypertrophy, dilation, and dysfunction by using the transgenic Gαq mice which represent a well-characterized and highly relevant genetic mouse model of pathological hypertrophy and heart failure. We have shown that ROCK1 deletion prevented left ventricular dilation and contractile dysfunction in Gαq mice under basal condition. ROCK1 deletion also partially rescued bradycardia and improved contractile response to β-adrenergic stimulation in Gαq mice. Although the development of cardiomyocyte hypertrophy was not affected, ROCK1 deletion in Gαq mice resulted in a concentric hypertrophic phenotype associated with reduced induction of hypertrophic markers. Finally, ROCK1 deletion prevented down-regulation of type V adenylyl cyclase expression, which is a critical molecular defect contributing to the impaired β-adrenergic signaling in Gαq mice. The present study establishes for the first time a role for ROCK1 in cardiac dilation and contractile dysfunction.

scholarly journals Endogenous Relaxin Does Not Affect Chronic Pressure Overload-Induced Cardiac Hypertrophy and Fibrosis

Endocrinology ◽  
2007 ◽  
Vol 149 (2) ◽  
pp. 476-482 ◽  
Author(s):  
Qi Xu ◽  
Edna D. Lekgabe ◽  
Xiao-Ming Gao ◽  
Ziqiu Ming ◽  
Geoffrey W. Tregear ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Wild Type ◽  
Gene Profile ◽  
Aortic Constriction ◽  
Littermate Control ◽  
Lv Remodeling ◽  
Hypertrophic Myocardium

The effect of endogenous relaxin on the development of cardiac hypertrophy, dysfunction, and fibrosis remains completely unknown. We addressed this question by subjecting relaxin-1 deficient (Rln1−/−) and littermate control (Rln1+/+) mice of both genders to chronic transverse aortic constriction (TAC). The extent of left ventricular (LV) remodeling and dysfunction were studied by serial echocardiography over an 8-wk period and by micromanometry. The degree of hypertrophy was estimated by LV weight, cardiomyocyte size, and expression of relevant genes. Cardiac fibrosis was determined by hydroxyproline assay and quantitative histology. Expression of endogenous relaxin during the course of TAC was also examined. In response to an 8-wk period of pressure overload, TAC mice of both genotypes developed significant LV hypertrophy, fibrosis, hypertrophy related gene profile, and signs indicating congestive heart failure when compared with respective sham controls. The severity of these alterations was not statistically different between the two genotypes of either gender. Relaxin mRNA expression was up-regulated, whereas that of its receptor was unchanged in the hypertrophic myocardium of wild-type mice. Collectively, the extent of pressure overload-induced LV hypertrophy, fibrosis, and dysfunction were comparable between Rln1+/+ and Rln1−/− mice. Thus, although up-regulated in its expression, endogenous relaxin had no significant effect on the progression of cardiac maladaptation and dysfunction in the setting of chronic pressure overload.

Abstract 19273: Fibroblast-Derived TSP1, via CD47, Upregulates Connective Tissue Growth Factor to Promote Left Ventricular Fibrosis and Heart Failure

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Maryam Sharifi-Sanjani ◽  
Kevin Beezhold ◽  
Hallie Cook ◽  
Jeffrey Baust ◽  
Jeffrey Isenberg
Keyword(s):  
Heart Failure ◽  
Growth Factor ◽  
Connective Tissue ◽  
Connective Tissue Growth Factor ◽  
The United States ◽  
Left Ventricular ◽  
Cardiac Fibroblast ◽  
Tissue Growth ◽  
Cell Surface Receptor ◽  
Wild Type

Background: An estimated 5.5 million individuals in the United States have left ventricular heart failure (LV HF). Therapeutics, while relieving symptoms and extending life in some cases, cannot resolve this process. LV HF is characterized by excessive accumulation of the extracellular matrix. The causes of this process remain incompletely understood. Our team has recently described a widely expressed cell surface receptor CD47 that is activated by its high affinity ligand, thrombospondin-1 (TSP1) to promote LV HF. However, the role of TSP1-CD47 signaling in promoting fibrosis, in general, and in the setting of LV HF, in specific, is unknown. Methods: Wild type mice expressing CD47 and mutated mice lacking CD47 (CD47 null) were subjected to transverse aortic constriction (TAC) for 4 weeks followed by open chest pressure-volume loop analysis of cardiac hemodynamics. Signal transduction was confirmed in isolated left ventricles (LV) and normal human ventricular fibroblast cell culture systems. Results: In biopsy samples from failing human hearts and in pre-clinical model of TAC-driven LV HF, TSP1-CD47 signaling was altered. Post-TAC wild type (CD47+/+) mice developed cardiac fibrosis, associated cardiac stiffness and HF. In contrast, CD47 null mice subjected to TAC showed enhanced cardiac function and decreased fibrosis concordant with suppression of TSP1. In cardiac resident fibroblasts, but not myocytes, hypoxia rapidly induced TSP1 protein, while treating with 7N3, a TSP1-based peptide mimetic that selectively binds CD47, increased connective tissue growth factor (CTGF) protein. Further, treating cardiac fibroblast with 7N3 increased fibroblast collagen production. Finally, CD47 blocking antibody mitigated established TAC-driven LV fibrosis and HF. Conclusion: These data identify a proximate role for activated cardiac fibroblast CD47 in promoting LV fibrosis associated with HF and suggest possible therapeutic opportunity.

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