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 Haploinsufficient Rock1+/− and Rock2+/− Mice Are Not Protected from Cardiac Inflammation and Postinflammatory Fibrosis in Experimental Autoimmune Myocarditis

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 700
Author(s):  
Karolina Tkacz ◽  
Filip Rolski ◽  
Marcin Czepiel ◽  
Edyta Działo ◽  
Maciej Siedlar ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Type I ◽  
Wild Type ◽  
Autoimmune Myocarditis ◽  
Inflammatory Monocytes ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Progressive cardiac fibrosis is a common cause of heart failure. Rho-associated, coiled-coil-containing protein kinases (ROCKs) have been shown to enhance fibrotic processes in the heart and in other organs. In this study, using wild-type, Rock1+/− and Rock2+/− haploinsufficient mice and mouse model of experimental autoimmune myocarditis (EAM) we addressed the role of ROCK1 and ROCK2 in development of myocarditis and postinflammatory fibrosis. We found that myocarditis severity was comparable in wild-type, Rock1+/− and Rock2+/− mice at day 21 of EAM. During the acute stage of the disease, hearts of Rock1+/− mice showed unaffected numbers of CD11b+CD36+ macrophages, CD11b+CD36–Ly6GhiLy6chi neutrophils, CD11b+CD36–Ly6G–Ly6chi inflammatory monocytes, CD11b+CD36–Ly6G–Ly6c– monocytes, CD11b+SiglecF+ eosinophils, CD11b+CD11c+ inflammatory dendritic cells and type I collagen-producing fibroblasts. Isolated Rock1+/− cardiac fibroblasts treated with transforming growth factor-beta (TGF-β) showed attenuated Smad2 and extracellular signal-regulated kinase (Erk) phosphorylations that were associated with impaired upregulation of smooth muscle actin alpha (αSMA) protein. In contrast to cardiac fibroblasts, expanded Rock1+/− heart inflammatory myeloid cells showed unaffected Smad2 activation but enhanced Erk phosphorylation following TGF-β treatment. Rock1+/− inflammatory cells responded to TGF-β by a reduced transcriptional profibrotic response and failed to upregulate αSMA and fibronectin at the protein levels. Unexpectedly, in the EAM model wild-type, Rock1+/− and Rock2+/− mice developed a similar extent of cardiac fibrosis at day 40. In addition, hearts of the wild-type and Rock1+/− mice showed comparable levels of cardiac vimentin, periostin and αSMA. In conclusion, despite the fact that ROCK1 regulates TGF-β-dependent profibrotic response, neither ROCK1 nor ROCK2 is critically involved in the development of postinflammatory fibrosis in the EAM model.

Myocarditis triggers inflammatory response in cardiac fibroblasts and profibrotic activation of myeloid and endothelial cells in mouse model of experimental autoimmune myocarditis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K Tkacz ◽  
E Dzialo ◽  
K Weglarczyk ◽  
M Czepiel ◽  
M Siedlar ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Collagen Type ◽  
Cardiac Fibroblasts ◽  
Myeloid Cells ◽  
Collagen Type I ◽  
Funding Source ◽  
Type I ◽  
Autoimmune Myocarditis ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Abstract Background/Introduction Myocarditis, a heart-specific inflammation, is a common cause of pathological tissue remodeling and cardiac fibrosis resulting in stiffening of ventricles, functional impairment and heart failure. Immunization of susceptible mice with alpha myosin heavy chain (αMyHC) and complete Freund's adjuvant (CFA) induces CD4+ T cell-mediated experimental autoimmune myocarditis (EAM). In EAM model, resolution of acute cardiac inflammation is followed by a progressive dilated cardiomyopathy and systolic dysfunction. Purpose The aim of our study was to identify the role of resident cardiac fibroblasts, cardiac endothelial as well as inflammatory myeloid cells during the course of EAM. Methods EAM was induced by immunization with αMyHC/CFA in reporter BALB/c mice expressing EGFP under collagen type I promoter (Coll-EGFP) and RFP under a control of α-smooth muscle actin (αSMA) promoter (αSMA-RFP). Using flow cytometry analysis, cardiac cells were phenotyped and quantified at inflammatory (d19–21) and fibrotic (d40) stage of EAM. Sorted EGFP-positive cardiac fibroblasts obtained from healthy and myocarditis-positive mice (day 21 of EAM) were comparatively analyzed for the whole genome transcriptomics using the Next Generation Sequencing with read length 2x150bp and 20–30 million reads per sample. Results A massive infiltration of inflammatory CD45+CD11b+ myeloid cells (mainly CD11b+CD36+ macrophages, CD11b+CD36–Ly6GhiLy6chi neutrophils, CD11b+CD36–Ly6G–Ly6c– monocytes, CD11b+CD36–Ly6G–Ly6chi inflammatory monocytes) was observed at day 21 of EAM. Myeloid cells as well as endothelial cells showed increased production of type I collagen at day 21, which was further reduced at day 40 of EAM. At day 21, collagen-producing endothelial cells showed particularly elevated levels of adhesion molecules ICAM and VCAM. On the other hand, the total number of EGFP-positive cardiac fibroblasts remained unchanged during the course of EAM, as well as the percentage of cardiac fibroblasts positive for αSMA (myofibroblasts). Gene ontology analysis of transcripts differentially regulated in cardiac fibroblasts during acute myocarditis pointed mainly to activation of immune processes, response to stress, cytoskeletal and extracellular matrix organization. Specifically, in EAM at day 21 cardiac fibroblasts increased transcription of chemokines (Ccl6, Ccl9, Cxcl2, Cxcl3, Cxcl5, Cxcl9, Cxcl13), collagens (Col6a4, Col6a5, Col9a1, Col9a3, Col11a2, Col12a1, Col24a1, Col28a1), and genes involved in ECM biology (Bmp7, Kng2, Lgals3, Cthrc1, Cela1, Spn). Conclusions In EAM model, inflammatory myeloid and cardiac endothelial cells seem to contribute to excessive collagen type I production, whereas cardiac fibroblasts actively participate in inflammatory and profibrotic responses. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The National Science Centre (Poland)

scholarly journals Blocking LFA-1 Aggravates Cardiac Inflammation in Experimental Autoimmune Myocarditis

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1267 ◽  
Author(s):  
Ludwig T. Weckbach ◽  
Andreas Uhl ◽  
Felicitas Boehm ◽  
Valentina Seitelberger ◽  
Bruno C. Huber ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Ratio ◽  
Heart Weight ◽  
Lymphocyte Function ◽  
Body Weight Ratio ◽  
Antibody Treatment ◽  
Autoimmune Myocarditis ◽  
Cardiac Inflammation ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

The lymphocyte function-associated antigen 1 (LFA-1) is a member of the beta2-integrin family and plays a pivotal role for T cell activation and leukocyte trafficking under inflammatory conditions. Blocking LFA-1 has reduced or aggravated inflammation depending on the inflammation model. To investigate the effect of LFA-1 in myocarditis, mice with experimental autoimmune myocarditis (EAM) were treated with a function blocking anti-LFA-1 antibody from day 1 of disease until day 21, the peak of inflammation. Cardiac inflammation was evaluated by measuring infiltration of leukocytes into the inflamed cardiac tissue using histology and flow cytometry and was assessed by analysis of the heart weight/body weight ratio. LFA-1 antibody treatment severely enhanced leukocyte infiltration, in particular infiltration of CD11b+ monocytes, F4/80+ macrophages, CD4+ T cells, Ly6G+ neutrophils, and CD133+ progenitor cells at peak of inflammation which was accompanied by an increased heart weight/body weight ratio. Thus, blocking LFA-1 starting at the time of immunization severely aggravated acute cardiac inflammation in the EAM model.

scholarly journals Effects of 1, 25-Dihydroxyvitamin D3 on Experimental Autoimmune Myocarditis in Mice

2016 ◽  
Vol 38 (6) ◽  
pp. 2219-2229 ◽  
Author(s):  
Fen Hu ◽  
Lianhua Yan ◽  
Shuai Lu ◽  
Wenhan Ma ◽  
Ya Wang ◽  
...  
Keyword(s):  
Beclin 1 ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Heart Weight ◽  
Autoimmune Myocarditis ◽  
Inflammatory Infiltration ◽  
Western Blots ◽  
Dihydroxyvitamin D3 ◽  
Multiple Systems ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Background/Aims: Myocarditis is an important inflammatory disease of the heart which causes life-threatening conditions. 1, 25(OH)2 D3 has effects on multiple systems and diseases. The present study was aimed to investigate the effect of 1, 25(OH)2 D3 on experimental autoimmune myocarditis (EAM), and explored the underlying mechanisms involved. Methods: EAM was induced by immunizing BALB/c mice with cardiac α-myosin heavy chain peptides (MyHC-α). 1, 25(OH)2 D3 (1,000 ng/kg once) or vehicle was administered intraperitoneally every other day during the entire experiment. On day 21, transthoracic echocardiography was performed and cardiac inflammatory infiltration was detected by hematoxylin and eosin (HE). The terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, and Western blots for the expression of protein caspase-3 and cleaved-caspase3 were used to evaluate apoptosis. Transmission electron microscopy and Western blots for the expression of protein Beclin-1, LC3B, and P62 were used to evaluate autophagy. Results: The ratio of heart weight/body weight was significantly reduced in 1, 25(OH)2 D3 -treated EAM mice, compared with vehicle -treated ones. 1, 25(OH)2 D3 treatment improved cardiac function, diminished cell infiltration in cardiac, suppressed myocardial apoptosis, decreased the number of autophagosomes, and decreased the protein expression of Beclin-1, LC3-II and p62. Conclusions: The present results demonstrated that administration of 1, 25(OH)2 D3 decreased EAM severity. 1, 25(OH)2 D3 treatment may be a feasible therapeutic approach for EAM.

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

Abstract 17425: Curcumin Ameliorates Experimental Autoimmune Myocarditis by Inducing M2 Macrophage Polarization

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Shanshan Gao ◽  
Na Liu ◽  
Lijun Wang ◽  
Fangyuan Chen ◽  
Hongjun You ◽  
...  
Keyword(s):  
Mrna Level ◽  
Heart Weight ◽  
M2 Macrophage ◽  
Autoimmune Myocarditis ◽  
Ppar Γ ◽  
Raw264.7 Macrophages ◽  
M2 Polarization ◽  
Experimental Autoimmune Myocarditis ◽  
M2 Phenotype ◽  
Experimental Autoimmune

AIMS: Our previous study showed that curcumin, the main active ingredient in turmeric, induces the polarization of macrophages to anti-inflammatory M2 phenotype. In this study, we addressed the underlying mechanisms and observed whether curcumin exerts its protective effects on experimental autoimmune myocarditis (EAM) by facilitating the M2 phenotype polarization of macrophages. METHODS AND RESULTS: The mRNA and protein expression of M2 markers, including MMR, Arg-1, KLF-4 and PPAR-γ, were obviously up-regulated in curcumin-treated RAW264.7 macrophages. Curcumin increased not only IL-4 and IL-13 mRNA expression, but also protein content of these two cytokines in supernatant. The STAT6 inhibitor leflunomide antagonized the induction of MMR, Arg-1, KLF-4 and PPAR-γ by curcumin in RAW264.7 cells, which is suggested that curcumin induces macrophages M2 polarization through secretion of IL-4 and IL-13 in an autocrine manner. In vivo, 6-week-old male Lewis rats were immunized with myosin to induce EAM and orally administrated with curcumin (50mg/kg/day) or corn oil for 3 weeks after myosin injection. Cardiac functional parameters, including LVFS, EF, LVESD and HR, were significantly improved by curcumin treatment. Curcumin also reduced the heart weight-to-body weight ratio, inflammatory cell infiltration and the myocardial mRNA level of IL-1β and iNOS. Meanwhile, the myocardial mRNA level of KLF4, MMR and Arg-1 were markedly up-regulated by curcumin. Immunofluorescence assay showed that the number of CD68+MMR+ and CD68+Arg-1+ double positive macrophages in curcumin-treated myocardial tissue was obviously more than vehicle-treated ones. CONCLUSIONS: Taken together, these results show that curcumin ameliorates EAM by attenuating inflammation and by inducing macrophage M2 polarization.

scholarly journals Quercetin Ameliorates Experimental Autoimmune Myocarditis in Rats

2010 ◽  
Vol 13 (3) ◽  
pp. 311 ◽  
Author(s):  
Marina Milenković ◽  
Nevena Arsenović-Ranin ◽  
Zorica Stojić-Vukanić ◽  
Biljana Bufan ◽  
Dragana Vučićević ◽  
...  
Keyword(s):  
Histopathological Examination ◽  
Weight Ratio ◽  
Heart Weight ◽  
Tnf Alpha ◽  
Dark Agouti ◽  
Autoimmune Myocarditis ◽  
Experimental Autoimmune Myocarditis ◽  
Anti Inflammatory ◽  
Culture Supernatants ◽  
Experimental Autoimmune

Purpose: Experimental autoimmune myocarditis (EAM) in rats is an animal model of human giant cell myocarditis and post-myocarditis dilated cardiomyopathy. The pathogenesis of EAM has not been elucidated, but there is accumulating evidence that cytokines secreted from monocytes/macrophages and T cells play a crucial role in the induction and progression of disease. Flavonoids are a large group of polyphenolic compounds abundantly present in the human diet, which scavenge oxygen radicals and have anti-inflammatory activities. Having in mind in vivo beneficial effects of flavonoid quercetin in different animal models of immunoinflammatory diseases such as experimental autoimmune encephalomyelitis and adjuvant arthritis, on the one side, and its in vitro suppressive effect on production of tumor necrosis factor–alpha (TNF-alpha on the other side, we investigated the effects of quercetin on EAM in rats. Methods: Myocarditis was induced in Dark Agouti (DA) rats by injection of porcine cardiac myosin and quercetin at doses of 10 or 20 mg/kg was orally administered from days 0 to 21 after induction of disease. The severity of myocarditis was evaluated by determination of heart weight / body weight ratio (Hw/Bw) and histopathological examination of hearts. The levels of cytokines (TNF-alpha, IL-12, IL-17 and IL-10) in serum and lymph node cells (LNC) culture supernatants were measured by ELISA. Results: The rats treated with 20 mg/kg of quercetin had significantly decreased incidence of EAM, Hw/Bw, macroscopic and microscopic scores of hearts. Further, in EAM rats treated with quercetin levels of TNF-alpha and IL-17 were significantly lower, while the level of IL-10 was significantly higher both in serum and culture supernatants of LNC stimulated with concanavalin A compared with vehicle-treated animals. Conclusions: The present study suggests that quercetin ameliorates EAM, at least in part, by interfering production of proinflammatory (TNF-alpha and IL-17) and/or anti-inflammatory (IL-10) cytokines.

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