scholarly journals Mast cells regulate myofilament calcium sensitization and heart function after myocardial infarction

2016 ◽  
Vol 213 (7) ◽  
pp. 1353-1374 ◽  
Author(s):  
Anta Ngkelo ◽  
Adèle Richart ◽  
Jonathan A. Kirk ◽  
Philippe Bonnin ◽  
Jose Vilar ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Mast Cells ◽  
Cardiac Function ◽  
Cardiac Remodeling ◽  
Molecular Mechanisms ◽  
Troponin I ◽  
Heart Function ◽  
Ischemic Disease ◽  
Cardiomyocyte Contractility ◽  
The Impact

Acute myocardial infarction (MI) is a severe ischemic disease responsible for heart failure and sudden death. Inflammatory cells orchestrate postischemic cardiac remodeling after MI. Studies using mice with defective mast/stem cell growth factor receptor c-Kit have suggested key roles for mast cells (MCs) in postischemic cardiac remodeling. Because c-Kit mutations affect multiple cell types of both immune and nonimmune origin, we addressed the impact of MCs on cardiac function after MI, using the c-Kit–independent MC-deficient (Cpa3Cre/+) mice. In response to MI, MC progenitors originated primarily from white adipose tissue, infiltrated the heart, and differentiated into mature MCs. MC deficiency led to reduced postischemic cardiac function and depressed cardiomyocyte contractility caused by myofilament Ca2+ desensitization. This effect correlated with increased protein kinase A (PKA) activity and hyperphosphorylation of its targets, troponin I and myosin-binding protein C. MC-specific tryptase was identified to regulate PKA activity in cardiomyocytes via protease-activated receptor 2 proteolysis. This work reveals a novel function for cardiac MCs modulating cardiomyocyte contractility via alteration of PKA-regulated force–Ca2+ interactions in response to MI. Identification of this MC-cardiomyocyte cross-talk provides new insights on the cellular and molecular mechanisms regulating the cardiac contractile machinery and a novel platform for therapeutically addressable regulators.

Abstract 213: Myofilament Ca2+ Sensitization and Site-specific Phosphorylation of Contractile Proteins Following Myocardial Infarction: A Novel Role for Mast Cells

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Anta Ngkelo ◽  
Jonathan Kirk ◽  
Adele Richart ◽  
Philippe Bonnin ◽  
Jose Vilar ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Mast Cell ◽  
Mast Cells ◽  
Cardiac Function ◽  
Cardiac Remodeling ◽  
Inflammatory Cells ◽  
Left Ventricular ◽  
Significant Difference ◽  
Cardiomyocyte Contractility ◽  
The Impact

Inflammatory cells orchestrate post-ischemic cardiac remodeling after myocardial infarction (MI). Studies in Kit mutant mice suggest key roles for mast cells in post-ischemic tissue remodeling. However, Kit mutations affect multiple cell types of both immune and non-immune origin. The aim of this study was to address the impact of mast cells on cardiac function following MI, using selectively mast cell-deficient mice (Cpa3Cre/+ mice). In response to myocardial infarction, mast cells progenitors’ numbers (Lin-CD45+CD34+FcγRII/IIIhighβ7+) increased in the white adipose tissue (day 3) and in the heart (day 5) and mature mast cells (CD117+FcεRI+Sca1+) peaked at day 7 in the cardiac tissue. To assess the functional effect of this mast cell infiltration in the heart, cardiac function 14 days following MI was assessed in wild-type (WT) and Cpa3Cre/+ mice. There was a significant decrease of the left ventricular shortening fraction in Cpa3Cre/+ compared to WT mice (17.27±1.9 % vs 28.15±1.7, p<0.01) that was not due to adverse cardiac remodeling; with no significant difference on levels of fibrosis, cardiomyocyte apoptosis, infarct size or neovascularization. By contrast, we observed a significant reduction in cardiomyocyte contractility (both cell shortening and ±dL/dt) in Cpa3Cre/+ mice compared to WT mice 14 days post MI. In addition, Ca2+ sensitivity (EC50) declined in Cpa3Cre/+ -derived skinned myocytes (p<0.01 vs WT) and correlated with increased PKA-dependent phosphorylation of both cardiac troponin (cTn)I (Ser22/23) and myosin-binding protein-C (MyBPC) (Ser273) (p<0.05). This study identifies a novel function of mast cells on modulating cardiomyocyte contractility via alteration of PKA-regulated Ca2+ handling and myofilament protein phosphorylation. Identification of the mast cell-dependent signaling pathway that targets cardiac performance will provide a new platform of regulators with potential cardioprotective properties.

scholarly journals Voluntary exercise and cardiac remodeling in a myocardial infarction model

Open Medicine ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 545-555
Author(s):  
Hamad Al Shahi ◽  
Tomoyasu Kadoguchi ◽  
Kazunori Shimada ◽  
Kosuke Fukao ◽  
Satoshi Matsushita ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Cardiac Remodeling ◽  
Skeletal Muscles ◽  
Wheel Running ◽  
Voluntary Exercise ◽  
Fibroblast Growth Factor 21 ◽  
Expression Levels ◽  
Factor Α ◽  
Necrosis Factor

AbstractWe investigated the effects of voluntary exercise after myocardial infarction (MI) on cardiac function, remodeling, and inflammation. Male C57BL/6J mice were divided into the following four groups: sedentary + sham (Sed-Sh), sedentary + MI (Sed-MI), exercise + sham (Ex-Sh), and exercise + MI (Ex-MI). MI induction was performed by ligation of the left coronary artery. Exercise consisting of voluntary wheel running started after the operation and continued for 4 weeks. The Ex-MI mice had significantly increased cardiac function compared with the Sed-MI mice. The Ex-MI mice showed significantly reduced expression levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 in the infarcted area of the left ventricle compared with the Sed-MI mice. In the Ex-MI mice, the expression levels of fibrosis-related genes including collagen I and III were decreased compared to the Sed-MI mice, and the expression levels of IL-1β, IL-6, follistatin-like 1, fibroblast growth factor 21, and mitochondrial function-related genes were significantly elevated in skeletal muscle compared with the Sed mice. The plasma levels of IL-6 were also significantly elevated in the Ex-MI group compared with the Sed-MI groups. These findings suggest that voluntary exercise after MI may improve in cardiac remodeling associated with anti-inflammatory effects in the myocardium and myokine production in the skeletal muscles.

Inhibition of mitochondrial fission as a novel therapeutic strategy to reduce mortality upon myocardial infarction

2018 ◽  
Vol 132 (20) ◽  
pp. 2163-2167 ◽  
Author(s):  
Hannah A. Cooper ◽  
Satoru Eguchi
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Molecular Mechanisms ◽  
Ischemia Reperfusion ◽  
Mitochondrial Fission ◽  
Future Research ◽  
Mitochondrial Homeostasis ◽  
Acute Mi ◽  
Future Research Directions ◽  
Receive Treatment

Ischemia reperfusion (I/R) injury is a common event following myocardial infarction (MI) resulting in excessive oxidative stress, calcium overload, inflammation, and cardiomyocyte death. Mitochondrial homeostasis including their dynamics are imbalanced in cardiac I/R injury in favor of increased mitochondrial fission. Inhibition of mitochondrial fission prior to I/R injury is protective and improves cardiac function following MI. Clinically, patients with MI often receive treatment following initiation of the ischemic event. Thus, treatments with more realistic timing would have better translational value and are important to research. In a recent study published in Clinical Science, Maneechote et al. [Clin. Sci. (2018) 132, 1669–1683] examined the effect of inhibiting mitochondrial fission using the mitochondrial division inhibitor (Mdivi-1) at different time points, pre-ischemia, during-ischemia, and upon onset of reperfusion, in a rat cardiac I/R model. The findings showed the greatest cardiac function improvement with pre-ischemia treatment along with decreased mitochondrial fragmentation and increased mitochondrial function. Mdivi-1 given during ischemia and at onset of reperfusion also improved cardiac function, but to a lesser extent than pre-ischemia intervention. Maneechote et al. postulated that the LV protection by Mdivi-1 in cardiac I/R could be due to an improvement in mitochondrial dysfunction through attenuating excessive mitochondrial fission which then reduces apoptotic myocytes. Their findings provide new insights into future treatment of patients suffering acute MI which could consider targetting the excessive mitochondrial fission during cardiac ischemia or at onset of reperfusion. Here, we will further discuss the background of the study, potential molecular mechanisms of mitochondrial fission, consequences of the fission, and future research directions.

scholarly journals Mesenchymal stem cells with overexpression of Angiotensin-converting enzyme-2 improved the microenvironment and cardiac function in a rat model of myocardial infarction

2020 ◽  
Author(s):  
Chao Liu ◽  
Yue Fan ◽  
Hong-Yi Zhu ◽  
Lu zhou ◽  
Yu Wang ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Angiotensin Converting Enzyme ◽  
Cardiac Function ◽  
Heart Function ◽  
Tube Formation ◽  
Border Zone ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2

AbstractBackgroundAngiotensin-converting enzyme-2 (ACE2) overexpression improves left ventricular remodeling and function in diabetic cardiomyopathy; however, the effect of ACE2-overexpressed mesenchymal stem cells (MSCs) on myocardial infarction (MI) remains unexplored. This study aimed to investigate the effect of ACE2-overexpression on the function of MSCs and the therapeutic efficacy of MSCs for MI.MethodsMSCs were transfected with Ace2 gene using lentivirus, and then transplanted into the border zone of ischemic heart. The renin-angiotensin system (RAS) expression, nitric oxide synthase (NOS) expression, paracrine factors, anti-hypoxia ability, tube formation of MSCs, and heart function were determined.ResultsMSCs expressed little ACE2. ACE2-overexpression decreased the expression of AT1 and VEGF apparently, up-regulated the paracrine of HGF, and increased the synthesis of Angiotensin 1-7 in vitro. ACE2-overexpressed MSCs showed a cytoprotective effect on cardiomyocyte, and an interesting tube formation ability, decreased the heart fibrosis and infarct size, and improved the heart function.ConclusionTherapies employing MSCs with ACE2 overexpression may represent an effective treatment for improving the myocardium microenvironment and the cardiac function after MI.

Abstract 81: B Lymphocytes Trigger MCP3-Dependent Mobilization of Monocytes and Promote Adverse Ventricular Remodeling After Myocardial Infarction

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Yasmine Zouggari ◽  
Hafid Ait-Oufella ◽  
Philippe Bonnin ◽  
José Vilar ◽  
Coralie Guerin ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Bone Marrow ◽  
Inflammatory Response ◽  
Cardiac Function ◽  
B Cell ◽  
B Lymphocytes ◽  
Cardiac Remodeling ◽  
Ventricular Remodeling ◽  
Cell Depletion ◽  
B Cell Depletion

Leukocyte infiltration in ischemic areas is a hallmark of myocardial infarction, and persistent infiltration of innate immune cells, such as neutrophils and Ly6Chi monocytes, has been shown to promote adverse cardiac tissue remodeling. However, little is known regarding the role of mature B lymphocytes, which play a crucial role in the activation of the inflammatory response in several immune-mediated diseases. Here, we hypothesized that B lymphocytes might modulate the inflammatory response and affect the immune-dependent adverse cardiac remodeling. In a mouse model of myocardial infarction, cardiac B lymphocytes levels peaked at day 5 after the onset of infarction. Of interest, treatment with a CD20-specific monoclonal antibody decreased circulating and infiltrating B cell numbers (p=0.0008 and p=0.0002 vs control), reduced infarct size and post-ischemic immunoinflammatory response, and improved cardiac function (p=0.02 vs control) assessed by echocardiography. Intriguingly, B cell depletion was associated with an impairment of Ly6Chi monocytes mobilization from bone marrow (p=0.02 vs control), leading to reduced levels of circulating and infiltrating cardiac monocytes. The acute infarction led to transient increase of both MCP-1 and MCP-3 levels. Interestingly, B cell depletion was associated with a significant and selective reduction of MCP-3 (p=0.03 vs control) but did not alter MCP-1 levels (p=0.11). Cultured activated B cells released MCP-3 and treatment with a neutralizing MCP-3 antibody abrogated B lymphocytes-induced migration of cultured monocytes. Finally, transfer of B cell-depleted splenocytes into Rag1 -/- mice improved cardiac function after myocardial infarction compared to the transfer of non-depleted splenocytes (p=0.005). This effect was abrogated after re-supplementation with B lymphocytes isolated from wild-type mice (p=0.0007) but not from MCP-3-deficient animals (p=0.7008). In conclusion, we show that following acute myocardial infarction, B lymphocytes, trigger an MCP-3-dependent mobilization of Ly6Chi monocytes from the bone marrow to the blood, leading to their recruitment into the injured myocardium and to exacerbation of tissue inflammation, thereby promoting adverse cardiac remodeling.

Abstract 223: Troponin I Tyrosine Phosphorylation Modulation of Cardiac Function

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Elizabeth A Brundage ◽  
Brendan Agatisa-Boyle ◽  
Vikram Shettigar ◽  
Jae-Hoon Chung ◽  
Ziqing Qian ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Diastolic Dysfunction ◽  
Troponin I ◽  
Heart Function ◽  
Calcium Sensitivity ◽  
Regulatory Proteins ◽  
Myocardial Relaxation ◽  
Kinase Phosphorylation ◽  
Accelerated Relaxation

Heart failure results in depressed contraction and slowed relaxation, both of which limit heart function and contribute to the progression of heart disease. Currently there is no chronic therapy to accelerate relaxation and reverse the diastolic dysfunction present in heart failure. Myocardial relaxation is regulated by serine/threonine phosphorylation of key regulatory proteins. Tyrosine (Tyr) specific kinases are expressed in the heart but the Tyr phosphorylation of regulatory proteins to modulate heart function has not been demonstrated. To investigate the effects of Tyr kinase phosphorylation on cardiac contraction we employed a novel cell penetrating peptide to deliver a direct Tyr kinase activator into isolated adult myocytes. Results demonstrate Tyr kinases activation increases Tyr phosphorylation of the regulatory protein troponin I (TnI) at Tyr26. We have demonstrated that TnI Tyr26 phosphorylation is beneficial to cardiac health by decreasing calcium sensitivity and accelerating myofilament deactivation (key determinants in accelerating myocardial relaxation) and that TnI Tyr26 phosphorylation undergoes functional integration with TnI Ser23/24 resulting in further accelerated calcium dissociation (accelerated relaxation) without further decreased calcium sensitivity (no further depression of contraction). We now demonstrate TnI Tyr26 also undergoes novel signaling integration with TnI Ser23/24 phosphorylation increasing the rate of Tyr kinase mediated Tyr26 phosphorylation. For the first time we demonstrate tyrosine kinase phosphorylation of TnI at Tyr26 modulates cardiac function resulting in accelerated relaxation. Increasing TnI Tyr26 phosphorylation may therefore serve as a novel targeted mechanism for future therapeutic development to accelerate depressed myocardial relaxation and improve diastolic dysfunction in heart failure.

scholarly journals The Impact of a Non-Functional Thyroid Receptor Beta upon Triiodotironine-Induced Cardiac Hypertrophy in Mice

2015 ◽  
Vol 37 (2) ◽  
pp. 477-490 ◽  
Author(s):  
Güínever Eustáquio do Império ◽  
Isalira Peroba Ramos ◽  
Letícia Aragão Santiago ◽  
Guilherme Faria Pereira ◽  
Norma Aparecida dos Santos Almeida ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Cardiac Hypertrophy ◽  
Cardiac Function ◽  
Hormone Receptors ◽  
Heart Function ◽  
Hypertrophic Growth ◽  
Regulation Mechanisms ◽  
Heart Functions ◽  
The Impact

Background/Aims: Thyroid hormone (TH) signalling is critical for heart function. The heart expresses thyroid hormone receptors (THRs); THRα1 and THRβ1. We aimed to investigate the regulation mechanisms of the THRβ isoform, its association with gene expression changes and implications for cardiac function. Methods: The experiments were performed using adult male mice expressing TRβΔ337T, which contains the Δ337T mutation of the human THRB gene and impairs ligand binding. Cardiac function and RNA expression were studied after hypo-or hyperthyroidism inductions. T3-induced cardiac hypertrophy was not observed in TRβΔ337T mice, showing the fundamental role of THRβ in cardiac hypertrophy. Results: We identified a group of independently regulated THRβ genes, which includes Adrb2, Myh7 and Hcn2 that were normally regulated by T3 in the TRβΔ337T group. However, Adrb1, Myh6 and Atp2a2 were regulated via THRβ. The TRβΔ337T mice exhibited a contractile deficit, decreased ejection fraction and stroke volume, as assessed by echocardiography. In our model, miR-208a and miR-199a may contribute to THRβ-mediated cardiac hypertrophy, as indicated by the absence of T3-regulated ventricular expression in TRβΔ337T mice. Conclusion: THRβ has important role in the regulation of specific mRNA and miRNA in T3-induced cardiac hypertrophic growth and in the alteration of heart functions.

scholarly journals Qiliqiangxin Attenuates Cardiac Remodeling via Inhibition of TGF-β1/Smad3 and NF-κB Signaling Pathways in a Rat Model of Myocardial Infarction

2018 ◽  
Vol 45 (5) ◽  
pp. 1797-1806 ◽  
Author(s):  
Anbang Han ◽  
Yingdong Lu ◽  
Qi Zheng ◽  
Jian Zhang ◽  
YiZhou Zhao ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Cardiac Function ◽  
Signaling Pathways ◽  
Rat Model ◽  
Cardiac Remodeling ◽  
Left Ventricular ◽  
Protective Effects ◽  
Tnf Α ◽  
Tgf Β1

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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