scholarly journals TLR4 Activation Promotes the Progression of Experimental Autoimmune Myocarditis to Dilated Cardiomyopathy by Inducing Mitochondrial Dynamic Imbalance

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Bangwei Wu ◽  
Jian Li ◽  
Huanchun Ni ◽  
Xinyu Zhuang ◽  
Zhiyong Qi ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Heart Function ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Autoimmune Myocarditis ◽  
Mitochondrial Dynamic ◽  
Transmission Electron Microscope Study ◽  
Experimental Autoimmune Myocarditis ◽  
Tlr4 Activation ◽  
Experimental Autoimmune

Mitochondrial dynamic imbalance associates with several cardiovascular diseases. However, the role of mitochondrial dynamics in TLR4 activation-mediated dilated cardiomyopathy (DCM) progress remains unknown. A model of experimental autoimmune myocarditis (EAM) was established in BALB/c mice on which TLR4 activation by LPS-EB or TLR4 inhibition by LPS-RS was performed to induce chronic inflammation for 5 weeks. TLR4 activation promoted the transition of EAM to DCM as demonstrated by increased cardiomyocyte apoptosis, myocardial fibrosis, ventricular dilatation, and declined heart function. TLR4 inhibition mitigated the above DCM changes. Transmission electron microscope study showed that mitochondria became fragmented, also with damaged crista in ultrastructure in EAM mice. TLR4 activation aggravated the above mitochondrial aberration, and TLR4 inhibition alleviated it. The mitochondrial dynamic imbalance and damage in DCM development were mainly associated with OPA1 downregulation, which may be caused by elevated TNF-α level and ROS stress after TLR4 activation. Furthermore, OMA1/YME1L abnormal degradation was involved in the OPA1 dysfunction, and intervening OMA1/YME1L in H9C2 significantly alleviated mitochondrial fission, ultrastructure damage, and cell apoptosis induced by TNF-α and ROS. These data indicate that TLR4 activation resulted in OPA1 dysfunction, promoting mitochondrial dynamic imbalance and damage, which may involve in the progress of EAM to DCM.

Carvedilol Inhibits Matrix Metalloproteinase-2 Activation in Experimental Autoimmune Myocarditis: Possibilities of Cardioprotective Application

2017 ◽  
Vol 23 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Monika Skrzypiec-Spring ◽  
Katarzyna Haczkiewicz ◽  
Agnieszka Sapa ◽  
Tomasz Piasecki ◽  
Joanna Kwiatkowska ◽  
...  
Keyword(s):  
Heart Failure ◽  
Troponin I ◽  
Heart Function ◽  
Heart Diseases ◽  
Acute Myocarditis ◽  
Study Groups ◽  
Matrix Metalloproteinase 2 ◽  
Autoimmune Myocarditis ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Aims: Acute myocarditis is a potentially lethal inflammatory heart disease that frequently precedes the development of dilated cardiomyopathy and subsequent heart failure. At present, there is no effective standardized therapy for acute myocarditis, besides the optimal care of heart failure and arrhythmias in accordance with evidence-based guidelines and specific etiology-driven therapy for infectious myocarditis. Carvedilol has been shown to be cardioprotective by reducing cardiac pro-inflammatory cytokines present in oxidative stress in certain heart diseases. However, effects of carvedilol administration in acute myocarditis with its impact on matrix metalloproteinases’ (MMPs) activation have not been elucidated. Methods and Results: Carvedilol in 3 doses (2, 10, and 30 mg/kg) was given daily to 3 study groups of rats (n = 8) with experimental autoimmune myocarditis by gastric gavage for 3 weeks. In comparison to untreated rats (n = 8) with induced myocarditis, carvedilol significantly prevented the left ventricle enlargement and/or systolic dysfunction depending on the dose in study groups. Performed zymography showed enhanced MMP-2 activity in untreated rats, while carvedilol administration reduced alterations. This was accompanied by prevention of troponin I release and myofilaments degradation in cardiac muscle tissue. Additionally, severe inflammatory cell infiltration was detected in the nontreated group. Carvedilol in all doses tested, had no impact on severity of inflammation. The severity of inflammation did not differ between study groups and in relation to the untreated group. Conclusions: The protective effects of carvedilol on heart function observed in the acute phase of experimental autoimmune myocarditis seem to be associated with its ability to decrease MMP-2 activity and subsequently prevent degradation of myofilaments and release of troponin I while not related to suppression of inflammation.

scholarly journals Activated myofibroblasts promote cardiac hypertrophy and systolic dysfunction independently of cardiac fibrosis in experimental autoimmune myocarditis

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
K Tkacz ◽  
A Jazwa-Kusior ◽  
F Rolski ◽  
E Dzialo ◽  
K Weglarczyk ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Dilated Cardiomyopathy ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Systolic Dysfunction ◽  
Heart Weight ◽  
Type I ◽  
Autoimmune Myocarditis ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Abstract Background/Introduction Heart-specific inflammation – myocarditis is a common cause dilated cardiomyopathy which is characterized by pathological tissue remodeling, ventricular stiffening, cardiomyopathy and heart failure. In experimental autoimmune myocarditis (EAM) susceptible mice immunized with alpha myosin heavy chain (αMyHC) and complete Freund's adjuvant (CFA) develop acute myocarditis driven by autoreactive CD4+ T cells that is followed by progressive fibrosis, cardiomyopathy and systolic dysfunction. Purpose The aim of the study was to investigate the role of cardiac fibroblasts and myofibroblasts in myocarditis and post-inflammatory dilated cardiomyopathy in mouse model of EAM. Methods EAM was induced in BALB/c mice by immunization with αMyHC/CFA. We used reporter mice expressing EGFP under collagen type I promoter (Coll-EGFP) and RFP under a control of α-smooth muscle actin (αSMA) promoter (αSMA-RFP) and transgenic αSMA-TK mice with ganciclovir-inducible ablation of proliferating myofibroblasts. Cardiac cells were quantified using flow cytometry. Cardiac fibroblasts (CD45-CD31-EGFP+) were sorted from healthy and myocarditis-positive (day 21) mice using BD FACSAria™ II Cell Sorter and analyzed for the whole genome transcriptomics by RNA sequencing. Echocardiography was performed on Vevo 2100 Imaging System. Cardiac fibrosis was assessed by Trichrome Massons's staining and hydroxyproline assay, whereas cardiac hypertrophy by analysing cross-sectional cardiomyocyte area. Profibrotic gene expression was assessed by qRT-PCR. Results The total number of cardiac fibroblasts (CD45-CD31-EGFP+) and the subset of myofibroblasts (CD45-CD31-EGFP+RFP+) remained unchanged at inflammatory (d21) and fibrotic stages (d40). Analysis of differentially expressed genes (min. 2x fold change, p value <0.05) pointed out activation of immune processes (mainly chemokine production), response to stress, cytoskeletal and extracellular matrix re-organization in cardiac fibroblasts in response to myocarditis. αSMA-TK mice treated with ganciclovir (from day 21) showed comparable percent of fibrotic area, but significantly reduced heart weight, decreased cardiomyocyte hypertrophy and improved ejection fraction and cardiac output at day 40 comparing to PBS-treated mice. Ganciclovir-treated mice showed also attenuated cardiac Acta2 and Srf but markedly enhanced Mmp2 expression. Conclusions In EAM model cardiac fibroblasts actively participate in proinflammatory and profibrotic responses, while activated myofibroblasts contribute to dilated cardiomyopathy development independently of cardiac fibrosis. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Science Centre (Poland)

scholarly journals Mulberry Leaf Diet Protects Against Progression of Experimental Autoimmune Myocarditis to Dilated Cardiomyopathy Via Modulation of Oxidative Stress and MAPK-Mediated Apoptosis

2013 ◽  
Vol 31 (6) ◽  
pp. 352-362 ◽  
Author(s):  
Somasundaram Arumugam ◽  
Sayaka Mito ◽  
Rajarajan A. Thandavarayan ◽  
Vijayasree V. Giridharan ◽  
Vigneshwaran Pitchaimani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dilated Cardiomyopathy ◽  
Autoimmune Myocarditis ◽  
Mulberry Leaf ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

scholarly journals The Impact of Circulating Mitochondrial DNA on Cardiomyocyte Apoptosis and Myocardial Injury After TLR4 Activation in Experimental Autoimmune Myocarditis

2017 ◽  
Vol 42 (2) ◽  
pp. 713-728 ◽  
Author(s):  
Bangwei Wu ◽  
Huanchun Ni ◽  
Jian Li ◽  
Xinyu Zhuang ◽  
Jinjin Zhang ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Troponin I ◽  
Tissue Injury ◽  
H9c2 Cells ◽  
Autoimmune Myocarditis ◽  
Cardiac Inflammation ◽  
Experimental Autoimmune Myocarditis ◽  
Tlr4 Activation ◽  
The Impact ◽  
Experimental Autoimmune

Background/Aims: Mitochondrial DNA (mtDNA), acting as a newly found ‘danger-associated molecular patterns’ (DAMPs), is released into circulation upon tissue injury and performs as a considerable activator of inflammation and immune response. However, the role of circulating mtDNA in experimental autoimmune myocarditis (EAM) as well as Toll like receptor4 (TLR4) mediated cardiac inflammation and injury remains unknown. Methods: A model of EAM was established in BALB/c mice by immunization with porcine cardiac myosin. Lipopolysaccharide (LPS) was used to stimulate TLR4 activation in EAM mice and H9C2 cells. Results: LPS stimulation significantly aggravated cardiac inflammation and tissue injury in EAM, as demonstrated by increased myocardium inflammatory cell infiltration, and up-regulated inflammatory cytokines and troponin I(TnI) level in serum. Circulating mtDNA level was increased in EAM and TLR4 activation led to a greater elevation, which may be related to Reactive oxygen species (ROS) stress involved mtDNA damage characterized by reduced mtDNA copy number in myocardium tissue. In addition, the expression of Toll like receptor9 (TLR9), a ligand of mtDNA, was significantly up-regulated in the myocardium of EAM and EAM LPS group; meanwhile, TLR9 inhibition by ODN 2088 caused an inhibited apoptosis in LPS treated H9C2 cells. Moreover, in EAM and EAM LPS group, simultaneously giving ODN 2088 treatment significantly ameliorated cardiac inflammation and tissue injury compared with untreated group. Conclusion: Increased circulating mtDNA combined with upregulated TLR9 expression may corporately play a role in EAM as well as TLR4 activation mediated cardiac inflammation and injury.

Telmisartan acts through the modulation of ACE-2/ANG 1–7/mas receptor in rats with dilated cardiomyopathy induced by experimental autoimmune myocarditis

Life Sciences ◽  
2012 ◽  
Vol 90 (7-8) ◽  
pp. 289-300 ◽  
Author(s):  
Vijayakumar Sukumaran ◽  
Punniyakoti T. Veeraveedu ◽  
Narasimman Gurusamy ◽  
Arun Prasath Lakshmanan ◽  
Ken'ichi Yamaguchi ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Autoimmune Myocarditis ◽  
Mas Receptor ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

scholarly journals Eosinophil-derived IL-4 drives progression of myocarditis to inflammatory dilated cardiomyopathy

2017 ◽  
Vol 214 (4) ◽  
pp. 943-957 ◽  
Author(s):  
Nicola L. Diny ◽  
G. Christian Baldeviano ◽  
Monica V. Talor ◽  
Jobert G. Barin ◽  
SuFey Ong ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Heart Function ◽  
Cell Type ◽  
Autoimmune Myocarditis ◽  
Large Numbers ◽  
Eosinophilic Myocarditis ◽  
Children And Young Adults ◽  
Experimental Autoimmune

Inflammatory dilated cardiomyopathy (DCMi) is a major cause of heart failure in children and young adults. DCMi develops in up to 30% of myocarditis patients, but the mechanisms involved in disease progression are poorly understood. Patients with eosinophilia frequently develop cardiomyopathies. In this study, we used the experimental autoimmune myocarditis (EAM) model to determine the role of eosinophils in myocarditis and DCMi. Eosinophils were dispensable for myocarditis induction but were required for progression to DCMi. Eosinophil-deficient ΔdblGATA1 mice, in contrast to WT mice, showed no signs of heart failure by echocardiography. Induction of EAM in hypereosinophilic IL-5Tg mice resulted in eosinophilic myocarditis with severe ventricular and atrial inflammation, which progressed to severe DCMi. This was not a direct effect of IL-5, as IL-5TgΔdblGATA1 mice were protected from DCMi, whereas IL-5−/− mice exhibited DCMi comparable with WT mice. Eosinophils drove progression to DCMi through their production of IL-4. Our experiments showed eosinophils were the major IL-4–expressing cell type in the heart during EAM, IL-4−/− mice were protected from DCMi like ΔdblGATA1 mice, and eosinophil-specific IL-4 deletion resulted in improved heart function. In conclusion, eosinophils drive progression of myocarditis to DCMi, cause severe DCMi when present in large numbers, and mediate this process through IL-4.

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