Both gain and loss of Nampt function promote pressure overload-induced heart failure

The heart requires high-energy production, but metabolic ability declines in the failing heart. Nicotinamide phosphoribosyl-transferase (Nampt) is a rate-limiting enzyme in the salvage pathway of nicotinamide adenine dinucleotide (NAD) synthesis. NAD is directly involved in various metabolic processes and may indirectly regulate metabolic gene expression through sirtuin 1 (Sirt1), an NAD-dependent protein deacetylase. However, how Nampt regulates cardiac function and metabolism in the failing heart is poorly understood. Here we show that pressure-overload (PO)-induced heart failure is exacerbated in both systemic Nampt heterozygous knockout (Nampt+/−) mice and mice with cardiac-specific Nampt overexpression (Tg-Nampt). The NAD level declined in Nampt+/− mice under PO (wild: 377 pmol/mg tissue; Nampt+/−: 119 pmol/mg tissue; P = 0.028). In cultured cardiomyocytes, Nampt knockdown diminished mitochondrial NAD content and ATP production (relative ATP production: wild: 1; Nampt knockdown: 0.56; P = 0.0068), suggesting that downregulation of Nampt induces mitochondrial dysfunction. On the other hand, the NAD level was increased in Tg-Nampt mice at baseline but not during PO, possibly due to increased consumption of NAD by Sirt1. The expression of Sirt1 was increased in Tg-Nampt mice, in association with reduced overall protein acetylation. PO-induced downregulation of metabolic genes was exacerbated in Tg-Nampt mice. In cultured cardiomyocytes, Nampt and Sirt1 cooperatively suppressed mitochondrial proteins and ATP production, thereby promoting mitochondrial dysfunction. In addition, Nampt overexpression upregulated inflammatory cytokines, including TNF-α and monocyte chemoattractant protein-1. Thus endogenous Nampt maintains cardiac function and metabolism in the failing heart, whereas Nampt overexpression is detrimental during PO, possibly due to excessive activation of Sirt1, suppression of mitochondrial function, and upregulation of proinflammatory mechanisms. NEW & NOTEWORTHY Nicotinamide phosphoribosyl-transferase (Nampt) is a rate-limiting enzyme in the salvage pathway of nicotinamide adenine dinucleotide synthesis. We demonstrate that pressure overload-induced heart failure is exacerbated in both systemic Nampt heterozygous knockout mice and mice with cardiac-specific Nampt overexpression. Both loss- and gain-of-function models exhibited reduced protein acetylation, suppression of metabolic genes, and mitochondrial energetic dysfunction. Thus endogenous Nampt maintains cardiac function and metabolism in the failing heart, but cardiac-specific Nampt overexpression is detrimental rather than therapeutic.

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A gene therapeutic approach to inhibit calcium and integrin binding protein 1 ameliorates maladaptive remodelling in pressure overload

Cardiovascular Research ◽

10.1093/cvr/cvy154 ◽

2018 ◽

Vol 115 (1) ◽

pp. 71-82 ◽

Cited By ~ 5

Author(s):

Andrea Grund ◽

Malgorzata Szaroszyk ◽

Janina K Döppner ◽

Mona Malek Mohammadi ◽

Badder Kattih ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Hypertrophy ◽

Cardiac Function ◽

Binding Protein ◽

Treatment Strategies ◽

Pressure Overload ◽

Cellular Growth ◽

Neonatal Rat ◽

Rat Cardiomyocytes ◽

Pathological Cardiac Hypertrophy

Abstract Aims Chronic heart failure is becoming increasingly prevalent and is still associated with a high mortality rate. Myocardial hypertrophy and fibrosis drive cardiac remodelling and heart failure, but they are not sufficiently inhibited by current treatment strategies. Furthermore, despite increasing knowledge on cardiomyocyte intracellular signalling proteins inducing pathological hypertrophy, therapeutic approaches to target these molecules are currently unavailable. In this study, we aimed to establish and test a therapeutic tool to counteract the 22 kDa calcium and integrin binding protein (CIB) 1, which we have previously identified as nodal regulator of pathological cardiac hypertrophy and as activator of the maladaptive calcineurin/NFAT axis. Methods and results Among three different sequences, we selected a shRNA construct (shCIB1) to specifically down-regulate CIB1 by 50% upon adenoviral overexpression in neonatal rat cardiomyocytes (NRCM), and upon overexpression by an adeno-associated-virus (AAV) 9 vector in mouse hearts. Overexpression of shCIB1 in NRCM markedly reduced cellular growth, improved contractility of bioartificial cardiac tissue and reduced calcineurin/NFAT activation in response to hypertrophic stimulation. In mice, administration of AAV-shCIB1 strongly ameliorated eccentric cardiac hypertrophy and cardiac dysfunction during 2 weeks of pressure overload by transverse aortic constriction (TAC). Ultrastructural and molecular analyses revealed markedly reduced myocardial fibrosis, inhibition of hypertrophy associated gene expression and calcineurin/NFAT as well as ERK MAP kinase activation after TAC in AAV-shCIB1 vs. AAV-shControl treated mice. During long-term exposure to pressure overload for 10 weeks, AAV-shCIB1 treatment maintained its anti-hypertrophic and anti-fibrotic effects, but cardiac function was no longer improved vs. AAV-shControl treatment, most likely resulting from a reduction in myocardial angiogenesis upon downregulation of CIB1. Conclusions Inhibition of CIB1 by a shRNA-mediated gene therapy potently inhibits pathological cardiac hypertrophy and fibrosis during pressure overload. While cardiac function is initially improved by shCIB1, this cannot be kept up during persisting overload.

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Abstract 14309: A Novel Fibroblast Activation Inhibitor, NM922, Attenuates Maladaptive Fibrotic Remodeling to Preserve Cardiac Function Following the Onset of Heart Failure

Circulation ◽

10.1161/circ.132.suppl_3.14309 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Jessica M Bradley ◽

Craig M Ziblich ◽

Kazi N Islam ◽

Amanda M Rushing ◽

David J Polhemus ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Function ◽

Structural Changes ◽

Volume Fraction ◽

Left Ventricular ◽

Normal Fibroblast ◽

Wall Thickening ◽

Cellular Mechanisms ◽

Collagen Formation ◽

Failing Heart

Background: Cardiac fibroblasts are critical mediators of fibrotic remodeling in the failing heart. These maladaptive structural changes can worsen cardiac function accelerating the progression to decompensated heart failure (HF). We investigated the effects of a novel inhibitor of the conversion of normal fibroblast to the myofibroblast phenotype in the setting of pressure overload induced HF. Methods: Male C57BL/6J mice (10 wks) were subjected to transverse aortic constriction (TAC; 27 g needle) and NM922 (NovoMedix, LLC50 mg/kg/d i.p.) or VEH (DMSO + HS-15) was administered daily starting at 6 wks post TAC. Echocardiography was assessed at baseline and for 16 wks post TAC. At the 16 wk endpoint, mice were sacrificed and hearts were collected for biochemical and molecular assessment. Results: NM922 significantly attenuated TAC-induced left ventricular (LV) dilation at 16 wks post TAC (LVEDD: 3.5 ± 0.1 vs. 4.5 ± 0.2 mm, p < 0.01; LVESD: 2.5 ± 0.2 vs. 3.8 ± 0.3 mm, p < 0.01) compared to VEH. NM922 treated mice displayed reduced wall thickening (LVPWd: 1.0 ± 0.03 vs. 1.2 ± 0.05 mm; p < 0.05) at 10 wks post TAC compared to VEH. LV ejection fraction (LVEF) was preserved in NM922 treated mice at 8-16 wks post TAC compared to VEH (*p < 0.05; **p < 0.001) compared to VEH. Treatment with NM922 resulted in reductions in heart (8.5 ± 0.5 vs. 12.0 ± 0.9 mg/mm; p < 0.01) and lung (8.2 ± 0.3 vs. 11.5 ± 0.6 mg/mm; p < 0.0001) weights compared to VEH. Picrosirius Red staining revealed that NM922 reduced cardiac interstitial collagen volume fraction by 50% (p < 0.05 vs. VEH). Circulating BNP levels trended toward lower (p = 0.08) in the NM922 mice when compared to VEH. Conclusion: Chronic treatment with NM922 following the onset of cardiac hypertrophy and HF resulted in attenuated myocardial collagen formation and adverse remodeling with preservation of LVEF. Future studies are aimed at further elucidation of the molecular and cellular mechanisms by which this novel agent protects the failing heart.

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Abstract 15981: DNA Single-strand Break-induced DNA Damage Response Causes Heart Failure

Circulation ◽

10.1161/circ.132.suppl_3.15981 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Tomoaki Higo ◽

Atsuhiko Naito ◽

Masato Shibamoto ◽

Jong-Kook Lee ◽

Shungo Hikoso ◽

...

Keyword(s):

Heart Failure ◽

Dna Damage ◽

Inflammatory Cytokines ◽

Dna Damage Response ◽

Nuclear Translocation ◽

Pressure Overload ◽

Strand Break ◽

Single Strand Break ◽

Failing Heart ◽

Damage Response

Introduction: The DNA damage response (DDR) pathway is activated upon DNA damage. In mitotic cells, the DDR plays essential role in maintaining genomic stability and preventing cancer formation. DNA damage and activation of the DDR are also observed in the post-mitotic cardiomyocytes of patients with end-stage heart failure, however, their roles in the pathogenesis of heart failure remains elusive. Methods and Results: We performed transverse aortic constriction (TAC) operation to produce mice model of pressure-overload induced heart failure. Alkaline- and neutral- comet assay revealed that unrepaired DNA single-strand break (SSB), not double-strand break, is accumulated in cardiomyocytes of the failing heart. Mice with cardiomyocyte-specific deletion of XRCC1, a scaffold protein essential for SSB repair, exhibited more severe heart failure and higher mortality after TAC operation. Knockdown of Xrcc1 using siRNA produced SSB accumulation in cardiomyocytes and SSB accumulation induced persistent DDR through activation of ataxia telangiectasia mutated (ATM) kinase. Activated ATM also induced nuclear translocation of NF-κB and increased the expression of inflammatory cytokines. Activation of DDR, nuclear translocation of NF-κB, and increased expression of inflammatory cytokines were also observed in the failing heart and were enhanced in the heart of cardiomyocyte-specific XRCC1 knockout mice. Conclusions: Unrepaired DNA SSB accumulates in post-mitotic cardiomyocytes and plays a pathogenic role in pressure overload-induced heart failure. Approaches that promote efficient SSB repair or suppress aberrant activation of DDR pathway may become a novel therapeutic strategy against heart failure.

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Abstract 86: Catabolic Remodeling of Branched Chain Amino Acids in Heart Failure

Circulation Research ◽

10.1161/res.111.suppl_1.a86 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Haipeng Sun ◽

Meiyi Zhou ◽

Chen Gao ◽

Kristine Olson ◽

Ji-Youn Youn ◽

...

Keyword(s):

Heart Failure ◽

Amino Acids ◽

Regulatory Protein ◽

Pressure Overload ◽

Branched Chain Amino Acids ◽

Atp Production ◽

Genetic Ablation ◽

Catabolic Genes ◽

Metabolic Remodeling ◽

Branched Chain

Metabolic remodeling is an integral part of heart failure. Although glucose and fatty acids metabolism have been extensively studied, little is known about the role of amino acids homeostasis in heart physiology and pathology. Branched chain amino acids (BCAAs), including leucine, isoleucine, and valine, are essential amino acids for both protein synthesis and cellular signaling. Elevated levels of BCAAs have been linked with heart failure. However, the underlying regulatory mechanism and functional significance of abnormal BCAA catabolism in heart failure have not been established. We found that genes involved in BCAA catabolism, including a key regulatory protein PP2Cm, are significantly down-regulated at mRNA as well as protein level in pressure-overload induced failing heart in mice. Furthermore, the concentrations of BCAA catabolic products branched-chain keto acids (BCKAs) are also elevated in heart tissues of post TAC mice. Interestingly, the down-regulation of BCAA catabolic genes mimics a similar expression pattern observed in fetal heart, suggesting that decreased BCAA catabolic activity is part of the metabolic remodeling in pathologically stressed heart from an adult to a fetal-like state. Genetic ablation of PP2Cm in mouse leads to defect in BCAA catabolism and accumulation of BCAAs and BCKAs in cardiac tissue and serum. PP2Cm deficient mice had lower cardiac contractility and higher susceptibility to develop heart failure under pressure overload. In addition, BCKAs treatment to isolated mitochondria resulted in lower oxygen consumption rate and ATP production. PP2Cm deficiency as well as BCKAs treatment induced oxidative stress in cardiomyocyte and antioxidant treatment ameliorated the development of heart failure in PP2Cm deficient animals. Together, these data indicated that BCAA catabolic remodeling is likely an integrated component of metabolic remodeling during heart failure. More importantly, mis-regulation of BCAA catabolism in heart promoted heart failure progression, involving direct impact on mitochondrial function and redox homeostasis in cardiomyocytes.

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Diverse regulation of IP3 and ryanodine receptors by pentazocine through σ1-receptor in cardiomyocytes

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00300.2013 ◽

2013 ◽

Vol 305 (8) ◽

pp. H1201-H1212 ◽

Cited By ~ 16

Author(s):

Hideaki Tagashira ◽

Md. Shenuarin Bhuiyan ◽

Kohji Fukunaga

Keyword(s):

Cardiac Hypertrophy ◽

Diastolic Pressure ◽

Ryanodine Receptors ◽

Pressure Overload ◽

Left Ventricular ◽

Female Rats ◽

In Vivo Studies ◽

Atp Production ◽

Cultured Cardiomyocytes

Although pentazocine binds to σ1-receptor (σ1R) with high affinity, the physiological relevance of its binding remains unclear. We first confirmed that σ1R stimulation with pentazocine rescues contractile dysfunction following pressure overload (PO)-induced cardiac hypertrophy ovariectomized (OVX) female rats. In in vivo studies, vehicle, pentazocine (0.5–1.0 mg/kg ip), and NE-100 (1.0 mg/kg po), a σ1R antagonist, were administered for 4 wk (once daily) starting from the onset of aortic banding after OVX. We also examined antihypertrophic effects of pentazocine (0.5–1 μM) in cultured cardiomyocytes exposed to angiotensin II. Pentazocine administration significantly inhibited PO-induced cardiac hypertrophy and rescued hypertrophy-induced impairment of cardiac dysfunctions such as left ventricular end-diastolic pressure, left ventricular developed pressure, and left ventricular contraction and relaxation (±dp/dt) rates. Coadministration of NE-100 with pentazocine eliminated pentazocine-induced amelioration of heart dysfunction. Interestingly, pentazocine administration inhibited PO-induced σ1R reduction and inositol-1,4,5-trisphosphate (IP3) receptor type 2 (IP3R2) upregulation in heart. Therefore, the reduced mitochondrial ATP production following PO was restored by pentazocine administration. Furthermore, we found that σ1R binds to the ryanodine receptor (RyR) in addition to IP3 receptor (IP3R) in cardiomyocytes. The σ1R/RyR complexes were decreased following OVX-PO and restored by pentazocine administration. We noticed that pentazocine inhibits the ryanodine-induced Ca2+ release from sarcoplasmic reticulum (SR) in cultured cardiomyocytes. Taken together, the stimulation of σ1R by pentazocine rescues cardiac dysfunction by restoring IP3R-mediated mitochondrial ATP production and by suppressing RyR-mediated Ca2+ leak from SR in cardiomyocytes.

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Distinct roles of resident and nonresident macrophages in nonischemic cardiomyopathy

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1720065115 ◽

2018 ◽

Vol 115 (20) ◽

pp. E4661-E4669 ◽

Cited By ~ 35

Author(s):

Xudong Liao ◽

Yuyan Shen ◽

Rongli Zhang ◽

Keiki Sugi ◽

Neelakantan T. Vasudevan ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Function ◽

Late Phase ◽

Myeloid Cells ◽

Pressure Overload ◽

Genetic Mutations ◽

Nonischemic Cardiomyopathy ◽

Resident Macrophage ◽

Temporal And Spatial

Nonischemic cardiomyopathy (NICM) resulting from long-standing hypertension, valvular disease, and genetic mutations is a major cause of heart failure worldwide. Recent observations suggest that myeloid cells can impact cardiac function, but the role of tissue-intrinsic vs. tissue-extrinsic myeloid cells in NICM remains poorly understood. Here, we show that cardiac resident macrophage proliferation occurs within the first week following pressure overload hypertrophy (POH; a model of heart failure) and is requisite for the heart’s adaptive response. Mechanistically, we identify Kruppel-like factor 4 (KLF4) as a key transcription factor that regulates cardiac resident macrophage proliferation and angiogenic activities. Finally, we show that blood-borne macrophages recruited in late-phase POH are detrimental, and that blockade of their infiltration improves myocardial angiogenesis and preserves cardiac function. These observations demonstrate previously unappreciated temporal and spatial roles for resident and nonresident macrophages in the development of heart failure.

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GW28-e0941 Increasing fatty acid utilization improves cardiac function through OPA1-mediated mitochondrial fusion in pressure overload-induced heart failure

Journal of the American College of Cardiology ◽

10.1016/j.jacc.2017.07.225 ◽

2017 ◽

Vol 70 (16) ◽

pp. C66

Author(s):

Yongzheng Guo ◽

Xing Zhang ◽

Feng Gao

Keyword(s):

Heart Failure ◽

Fatty Acid ◽

Cardiac Function ◽

Pressure Overload ◽

Mitochondrial Fusion ◽

Fatty Acid Utilization

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Osteopontin RNA aptamer can prevent and reverse pressure overload-induced heart failure

Cardiovascular Research ◽

10.1093/cvr/cvx016 ◽

2017 ◽

Vol 113 (6) ◽

pp. 633-643 ◽

Cited By ~ 21

Author(s):

Jihe Li ◽

Keyvan Yousefi ◽

Wen Ding ◽

Jayanti Singh ◽

Lina A. Shehadeh

Keyword(s):

Heart Failure ◽

Cardiac Function ◽

Cardiac Dysfunction ◽

Cardiac Fibrosis ◽

Cardiac Myocyte ◽

Pressure Overload ◽

Cardiomyocyte Hypertrophy ◽

Therapeutic Effects ◽

Rna Aptamer ◽

Myocyte Hypertrophy

Aims Cardiac myocyte hypertrophy, the main compensatory response to chronic stress in the heart often progresses to a state of decompensation that can lead to heart failure. Osteopontin (OPN) is an effector for extracellular signalling that induces myocyte growth and fibrosis. Although increased OPN activity has been observed in stressed myocytes and fibroblasts, the detailed and long term effects of blocking OPN signalling on the heart remain poorly defined. Targeting cardiac OPN protein by an RNA aptamer may be beneficial for tuning down OPN pathologic signalling. We aimed to demonstrate the therapeutic effects of an OPN RNA aptamer on cardiac dysfunction. Methods and results In vivo, we show that in a mouse model of pressure overload, treating at the time of surgeries with an OPN aptamer prevented cardiomyocyte hypertrophy and cardiac fibrosis, blocked OPN downstream signalling (PI3K and Akt phosphorylation), reduced expression of extracellular matrix (Lum, Col3a1, Fn1) and hypertrophy (Nppa, Nppb) genes, and prevented cardiac dysfunction. Treating at two months post-surgeries with the OPN aptamer reversed cardiac dysfunction and fibrosis and myocyte hypertrophy. While genetic homozygous deletion of OPN reduced myocardial wall thickness, surprisingly cardiac function and myocardial fibrosis, specifically collagen deposition and myofibroblast infiltration, were worse compared with wild type mice at three months of pressure overload. Conclusion Taken together, these data demonstrate that tuning down cardiac OPN signalling by an OPN RNA aptamer is a novel and effective approach for preventing cardiac hypertrophy and fibrosis, improving cardiac function, and reversing pressure overload-induced heart failure.

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Chronic Benzene Exposure Aggravates Pressure Overload-Induced Cardiac Dysfunction

10.1101/2021.08.31.458367 ◽

2021 ◽

Author(s):

Igor N Zelko ◽

Sujith Dassanayaka ◽

Marina V Malovichko ◽

Caitlin M Howard ◽

Lauren F Garrett ◽

...

Keyword(s):

Heart Failure ◽

Endothelial Cells ◽

Cardiac Function ◽

Cardiac Tissue ◽

Pressure Overload ◽

Endothelial Activation ◽

Air Exposure ◽

Benzene Exposure ◽

Increased Risk

Benzene is a ubiquitous environmental pollutant abundant in household products, petrochemicals and cigarette smoke. Benzene is a well-known carcinogen in humans and experimental animals; however, little is known about the cardiovascular toxicity of benzene. Recent population-based studies indicate that benzene exposure is associated with an increased risk for heart failure. Nonetheless, it is unclear whether benzene exposure is sufficient to induce and/or exacerbate heart failure. We examined the effects of benzene (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on transverse aortic constriction (TAC)-induced pressure overload in male C57BL/6J mice. Our data show that benzene exposure had no effect on cardiac function in the Sham group; however, it significantly compromised cardiac function as depicted by a significant decrease in fractional shortening and ejection fraction, as compared with TAC/Air-exposed mice. RNA-seq analysis of the cardiac tissue from the TAC/benzene-exposed mice showed a significant increase in several genes associated with adhesion molecules, cell-cell adhesion, inflammation, and stress response. In particular, neutrophils were implicated in our unbiased analyses. Indeed, immunofluorescence studies showed that TAC/benzene exposure promotes infiltration of CD11b+/S100A8+/myeloperoxidase+-positive neutrophils in the hearts by 3-fold. In vitro, the benzene metabolites, hydroquinone and catechol, induced the expression of P-selectin in cardiac microvascular endothelial cells by 5-fold and increased the adhesion of neutrophils to these endothelial cells by 1.5-2.0-fold. Benzene metabolite-induced adhesion of neutrophils to the endothelial cells was attenuated by anti-P-selectin antibody. Together, these data suggest that benzene exacerbates heart failure by promoting endothelial activation and neutrophil recruitment.

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