scholarly journals A Review of the Molecular Mechanisms Underlying the Development and Progression of Cardiac Remodeling

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Leonardo Schirone ◽  
Maurizio Forte ◽  
Silvia Palmerio ◽  
Derek Yee ◽  
Cristina Nocella ◽  
...  

Pathological molecular mechanisms involved in myocardial remodeling contribute to alter the existing structure of the heart, leading to cardiac dysfunction. Among the complex signaling network that characterizes myocardial remodeling, the distinct processes are myocyte loss, cardiac hypertrophy, alteration of extracellular matrix homeostasis, fibrosis, defective autophagy, metabolic abnormalities, and mitochondrial dysfunction. Several pathophysiological stimuli, such as pressure and volume overload, trigger the remodeling cascade, a process that initially confers protection to the heart as a compensatory mechanism. Yet chronic inflammation after myocardial infarction also leads to cardiac remodeling that, when prolonged, leads to heart failure progression. Here, we review the molecular pathways involved in cardiac remodeling, with particular emphasis on those associated with myocardial infarction. A better understanding of cell signaling involved in cardiac remodeling may support the development of new therapeutic strategies towards the treatment of heart failure and reduction of cardiac complications. We will also discuss data derived from gene therapy approaches for modulating key mediators of cardiac remodeling.

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
H Inazumi ◽  
K Kuwahara ◽  
Y Kuwabara ◽  
Y Nakagawa ◽  
H Kinoshita ◽  
...  

Abstract Background In the development of heart failure, pathological intracellular signaling reactivates fetal cardiac genes, which leads to maladaptive remodeling and cardiac dysfunction. We previously reported that a transcriptional repressor, neuron restrictive silencer factor (NRSF) represses fetal cardiac genes and maintains normal cardiac function under normal conditions, while hypertrophic stimuli de-repress this NRSF mediated repression via activation of CaMKII. Molecular mechanisms by which NRSF maintains cardiac systolic function remains to be determined, however. Purpose To elucidate how NRSF maintains normal cardiac homeostasis and identify the novel therapeutic targets for heart failure. Methods and results We generated cardiac-specific NRSF knockout mice (NRSF cKO), and found that these NRSF cKO showed cardiac dysfunction and premature deaths accompanied with lethal arrhythmias, as was observed in our previously reported cardiac-specific dominant-negative mutant of NRSF transgenic mice (dnNRSF-Tg). By cDNA microarray analysis of dnNRSF-Tg and NRSF-cKO, we identified that expression of Gnao1 gene encoding Gαo, a member of inhibitory G proteins, was commonly increased in ventricles of both types of mice. ChIP-seq analysis, reporter assay and electrophoretic mobility shift assay identified that NRSF transcriptionally regulates Gnao1 gene expression. Genetic Knockdown of Gαo in dnNRSF-Tg and NRSF-cKO by crossing these mice with Gnao1 knockout mice ameliorated the reduced systolic function, increased arrhythmogenicity and reduced survival rates. Transgenic mice expressing a human GNAO1 in their hearts (GNAO1-Tg) showed progressive cardiac dysfunction with cardiac dilation. Ventricles obtained from GNAO1-Tg have increased phosphorylation level of CaMKII and increased expression level of endogenous mouse Gnao1 gene. These data suggest that increased cardiac expression of Gαo is sufficient to induce pathological Ca2+-dependent signaling and cardiac dysfunction, and that Gαo forms a positive regulatory circuit with CaMKII and NRSF. Electrophysiological analysis in ventricular myocytes of dnNRSF-Tg revealed that impaired Ca2+ handling via alterations in localized L-type calcium channel (LTCC) activities; decreased T-tubular and increased surface sarcolemmal LTCC activities, underlies Gαo-mediated cardiac dysfunction. Furthermore, we also identified increased expression of Gαo in ventricles of two different heart failure mice models, mice with transverse aortic constriction and mice carrying a mutant cardiac troponin T, and confirmed that genetic reduction of Gαo prevented the progression of cardiac dysfunction in both types of mice. Conclusions Increased expression of Gαo, induced by attenuation of NRSF-mediated repression forms a pathological circuit via activation of CaMKII. This circuit exacerbates cardiac remodeling and progresses heart failure by impairing Ca2+ homeostasis. Gαo is a potential therapeutic target for heart failure. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grants-in –Aid for Scientific Research from the Japan Society for the Promotion of Science


2011 ◽  
Vol 4 (4) ◽  
pp. 463-473 ◽  
Author(s):  
Zaid A. Abassi ◽  
Yaron D. Barac ◽  
Sawa Kostin ◽  
Ariel Roguin ◽  
Elena Ovcharenko ◽  
...  

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Mathew Bull ◽  
Pooja Nair ◽  
Joshua Strom ◽  
Michael Gotthardt ◽  
Henk Granzier

Pathological remodeling is responsible for the functional deficits characteristic of heart failure patients. Understanding mechanotransduction is limited, but holds potential to provide novel therapeutic targets to treat patients with heart failure, especially those with diastolic dysfunction and preserved ejection fraction (HFpEF). Titin is the largest known protein and is abundant in muscle. It is the main contributor of passive stiffness in the heart and functions as a molecular mechano-sensor for stress and strain in the myocyte. Titin is composed of four distinct regions, (N-terminal Z-line, I-band, A-band, and C-terminal M-line), and acts as a molecular spring that is responsible for the assembly and maintenance of ultrastructure in the sarcomere. The elastic N2B element found in titin’s I-band region has been proposed as a mechano-sensor and signaling “hot spot” in the sarcomere. This study investigates the role of titin’s cardiac specific N2B element as sensor for stress and strain induced remodeling in the heart. The previously published N2B knock out (KO) mouse was subjected to a variety of stressors including transverse aortic constriction (TAC), aorto-caval fistula (ACF), chronic swimming, voluntary running and isoproterenol injections. Through chronic pathologic stress, pressure overload (TAC) and chronic volume overload (ACF), we found that the N2B element is necessary for the response to volume overload but not pressure overload as determined by changes in cardiac remodeling. Furthermore, the response to exercise either by chronic swimming or voluntary running was reduced in the N2B KO mouse. Finally, unlike the wild-type (WT) mouse, the N2B KO mouse did not respond to isoproterenol injections with hypertrophic remodeling. Ongoing work to elucidate the molecular pathways involving the N2B element and response to stress, is focused on its binding protein Four-and-a-half-LIM domains 2 (FHL2) and the mitogen activated protein kinase (MAPK) pathway. Taken together our data suggest that the N2B element contributes significantly to mechanotransduction in the heart.


2017 ◽  
Author(s):  
John K. Roberts ◽  
John P. Middleton

Cardiovascular disease is a common cause of death and disease in patients with end-stage renal disease (ESRD). Registry data show that 41% of deaths in ESRD patients are due to a variety of cardiovascular causes, such as acute myocardial infarction, congestive heart failure, arrhythmia/sudden cardiac death, and stroke. In the general population, each of these disease entities in isolation can be effectively managed according to evidence from large clinical trials and evidence-based guidelines. However, many of these trials did not include patients with ESRD, limiting the transferability of this evidence to the care of patients on dialysis. To complicate matters, cardiovascular events in ESRD patients are likely augmented from a unique interplay of cardiac risk due to both reduced kidney function and the necessity for artificial renal replacement therapies. In this light, the patient on dialysis is subjected to a series of unique factors: the continued presence of the metabolic perturbations of uremia and the peculiar environment of the dialysis treatment itself. Since the ESRD heart is under a considerable amount of strain due to chronic volume overload, rapid electrolyte and fluid shifts, and accelerated vascular calcification, management can be complex and outcomes multifactorial. In this review, we summarize the current evidence regarding management of acute myocardial infarction, heart failure, sudden cardiac death, and atrial fibrillation. We also address modifiable risk factors related to the dialysis procedure itself and highlight recent randomized controlled trials that included dialysis patients and measured important cardiovascular outcomes. 


2017 ◽  
Author(s):  
John K. Roberts ◽  
John P. Middleton

Cardiovascular disease is a common cause of death and disease in patients with end-stage renal disease (ESRD). Registry data show that 41% of deaths in ESRD patients are due to a variety of cardiovascular causes, such as acute myocardial infarction, congestive heart failure, arrhythmia/sudden cardiac death, and stroke. In the general population, each of these disease entities in isolation can be effectively managed according to evidence from large clinical trials and evidence-based guidelines. However, many of these trials did not include patients with ESRD, limiting the transferability of this evidence to the care of patients on dialysis. To complicate matters, cardiovascular events in ESRD patients are likely augmented from a unique interplay of cardiac risk due to both reduced kidney function and the necessity for artificial renal replacement therapies. In this light, the patient on dialysis is subjected to a series of unique factors: the continued presence of the metabolic perturbations of uremia and the peculiar environment of the dialysis treatment itself. Since the ESRD heart is under a considerable amount of strain due to chronic volume overload, rapid electrolyte and fluid shifts, and accelerated vascular calcification, management can be complex and outcomes multifactorial. In this review, we summarize the current evidence regarding management of acute myocardial infarction, heart failure, sudden cardiac death, and atrial fibrillation. We also address modifiable risk factors related to the dialysis procedure itself and highlight recent randomized controlled trials that included dialysis patients and measured important cardiovascular outcomes. 


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Claire Zhang ◽  
David M Calcagno ◽  
Avinash Toomu ◽  
Kenneth M Huang ◽  
Zhenxing Fu ◽  
...  

Myocardial infarction (MI) elicits a rapid and vigorous reaction from the bone marrow hematopoietic compartment, inducing a massive efflux of myeloid first responders into the bloodstream. These cells traffic to the infarct, where they mediate cardiac remodeling and repair through inflammatory signaling and recruitment of additional immune cells to the injured myocardium. A hyperinflammatory myeloid compartment, as is produced by mutations in epigenetic regulator TET2 associated with clonal hematopoiesis, can thus drive adverse cardiac remodeling after MI and accelerate progression to heart failure. Whether loss of TET2 alters the transcriptional landscape of MI-induced myelopoiesis remains to be investigated in an unbiased fashion. Here, we performed single-cell RNA sequencing of >16,000 bone marrow myeloid cells isolated from wild-type and Tet2 -/- mice after MI to characterize the emergency hematopoietic response in the presence and absence of TET2. Our data capture distinct transitional states of myeloid lineage commitment and maturation, originating from myeloid progenitors and progressing along divergent granulocytic and monocytic differentiation trajectories. Additionally, we delineate a subpopulation of interferon (IFN)-activated myeloid progenitors, monocytes, and neutrophils characterized by the concerted upregulation of various Type I IFN-stimulated genes, and find the fraction of IFN-activated cells, as well as the degree of activation, to be markedly higher in Tet2 -/- mice. We have previously described activation of this pathway after MI in mice, and demonstrated cardioprotective effects of its genetic or pharmacological inhibition. Our findings reveal heightened activation of the antiviral Type I interferon response among bone marrow myeloid cells of Tet2 -/- mice during MI-induced emergency hematopoiesis. This highlights IFN signaling as a potential candidate driver of cardiovascular pathologies (including atherosclerosis, myocardial infarction, and heart failure) associated with TET2-mediated clonal hematopoiesis. Further studies are necessary to investigate whether Tet2 -/- mice exhibit enhanced response to blockade of Type I IFN signaling after MI, and to determine whether myeloid cells of TET2 -mutant humans are similarly activated.


1999 ◽  
Vol 277 (5) ◽  
pp. H1786-H1792 ◽  
Author(s):  
Frans H. H. Leenen ◽  
Baoxue Yuan ◽  
Bing S. Huang

In chronic heart failure (CHF), sympathetic activity increases in parallel with the impairment of left ventricle (LV) function, and sympathetic hyperactivity has been postulated to contribute to the progression of heart failure. In the brain, compounds with ouabain-like activity (“ouabain,” for brevity) and the renin-angiotensin system contribute to sympathetic hyperactivity in rats with CHF after myocardial infarction (MI). In the present studies, we assessed whether, in rats, chronic blockade of brain “ouabain” or the brain renin-angiotensin system inhibits the post-MI LV dysfunction. In rats, an MI was induced by acute coronary artery ligation. At either 0.5 or 4 wk post-MI, chronic treatment with Fab fragments for blocking brain “ouabain” or with losartan for blocking brain AT1 receptors was started and continued until 8 wk post-MI using osmotic minipumps connected to intracerebroventricular cannulas. At 8 wk post-MI, in conscious rats, LV pressures were measured at rest and in response to volume and pressure overload, followed by LV passive pressure-volume curves in vitro. At 8 wk post-MI, control MI rats exhibited clear increases in LV end-diastolic pressure (LVEDP) at rest and in response to pressure and volume overload. LV pressure-volume curves in vitro showed a marked shift to the right. Intravenous administration of the Fab fragments or losartan at rates used for central blockade did not affect these parameters. In contrast, chronic central blockade with either Fab fragments or losartan significantly lowered LVEDP at rest (only in 0.5- to 8-wk groups) and particularly in response to pressure or volume overload. LV dilation, as assessed from LV pressure-volume curves, was also significantly inhibited. These results indicate that chronic blockade of brain “ouabain” or brain AT1 receptors substantially inhibits development of LV dilation and dysfunction in rats post-MI.


2018 ◽  
Vol 45 (5) ◽  
pp. 1797-1806 ◽  
Author(s):  
Anbang Han ◽  
Yingdong Lu ◽  
Qi Zheng ◽  
Jian Zhang ◽  
YiZhou Zhao ◽  
...  

Background/Aims: Qiliqiangxin (QL), a traditional Chinese medicine, has been demonstrated to be effective and safe for the treatment of chronic heart failure. Left ventricular (LV) remodeling causes depressed cardiac performance and is an independent determinant of morbidity and mortality after myocardial infarction (MI). Our previous studies have shown that QL exhibits cardiac protective effects against heart failure after MI. The objective of this study was to explore the effects of QL on myocardial fibrosis in rats with MI and to investigate the underlying mechanism of these effects. Methods: A rat model of acute myocardial infarction was induced by ligating the left anterior descending coronary artery. The rats were treated with QL (1.0 g/kg/day) for 4 weeks after surgery. Echocardiography and histology examination were performed to evaluate heart function and fibrosis, respectively. Protein levels of transforming growth factor-β1 (TGF-β1), phosphorylated Smad3 (p-Smad3), phosphorylated Smad7 (p-Smad7), collagen I (Col- I), alpha smooth muscle actin (a-SMA), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nuclear factor κB (NF-κB), and phosphorylated inhibitor of kappa B alpha (p-IκBα) were measured by western blot analysis. Results: QL treatment ameliorated adverse cardiac remodeling 8 weeks after AMI, including better preservation of cardiac function, decreased inflammation, and reduced fibrosis. In addition, QL treatment reduced Col-I, a-SMA, TGF-β1, and p-Smad3 expression levels but increased p-Smad7 levels in postmyocardial infarct rat hearts. QL administration also reduced the elevated levels of cardiac inflammation mediators, such as TNF-α and IL-6, as well as NF-κB and p-IκBα expression. Conclusions: QL therapy exerted protective effects against cardiac remodeling potentially by inhibiting TGF-β1/Smad3 and NF-κB signaling pathways, thereby preserving cardiac function, as well as reducing myocardial inflammation and fibrosis.


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