Abstract 296: Targeting Macrophage Subsets Attenuates Cardiac Remodeling and Dysfunction Following Experimental Myocarditis in Rat

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Shunit Rinkevich-Shop ◽  
Tamar Ben-Mordechai ◽  
David Kain ◽  
Micha S. Feinberg ◽  
Natalie Landa-Rouben ◽  
...  

Introduction: The mechanism of myocarditis is complex and poorly understood. Monocytes and macrophages comprise the majority of infiltrates in myocarditis. Hypothesis: We aimed to test the hypothesis that macrophage subsets have a key role in the pathogenesis and progression of myocarditis, and that targeting macrophages would modulate disease progression and outcome. Methods and Results: Experimental autoimmune myocarditis (EAM) was induced in 67 male Lewis rats. Of them, 27 were sacrificed at different time points to assess M1 and M2- macrophage subsets by flow cytometry. The remaining rats were randomized either to early macrophage depletion (from day 8-14 after EAM induction), by intravenous injections of clodronate-liposomes (CL), or late depletion (from day 15-35 after induction of EAM), or PBS-liposome injections (control). Left ventricula (LV) remodeling and function were assessed by echocardiography; before induction of EAM, before CL treatment, and 35 days after induction of EAM. Macrophages in the heart peaked at 21 days after induction of EAM (25±7%,p=0.0008).The number of M1 macrophages in the heart was highest at 14 days after EAM induction (16.3±2%), while M2 macrophages peaked at day 21 (15.5±2.7%,p=0.003). Early macrophage depletion (8-14d) decreased LV diastolic dimension and volume by 5.3±3.9% and 10.4±8% (p=0.04). Late macrophage depletion (15-35d) increased LV wall thickness and decreased LV systolic dimension and volume by 10.2±4% and 21±8% (p=0.03). Furthermore, late macrophage depletion increased LV ejection fraction and fractional shortening by 14.6±6% (p=0.01) and 22±10% (p=0.02) 35 days after EAM. Conclusions: Our study describes, for the first time, the kinetics of M1 and M2 macrophages in ocarditis and shows that macrophages contribute to the progression of adverse remodeling and dysfunction. Thus, targeting macrophages could be a new therapeutic strategy to improve cardiac remodeling and function in myocarditis.

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 868
Author(s):  
Fabiana Albani Zambuzi ◽  
Priscilla Mariane Cardoso-Silva ◽  
Ricardo Cardoso Castro ◽  
Caroline Fontanari ◽  
Flavio da Silva Emery ◽  
...  

Decitabine is an approved hypomethylating agent used for treating hematological malignancies. Although decitabine targets altered cells, epidrugs can trigger immunomodulatory effects, reinforcing the hypothesis of immunoregulation in treated patients. We therefore aimed to evaluate the impact of decitabine treatment on the phenotype and functions of monocytes and macrophages, which are pivotal cells of the innate immunity system. In vitro decitabine administration increased bacterial phagocytosis and IL-8 release, but impaired microbicidal activity of monocytes. In addition, during monocyte-to-macrophage differentiation, treatment promoted the M2-like profile, with increased expression of CD206 and ALOX15. Macrophages also demonstrated reduced infection control when exposed to Mycobacterium tuberculosis in vitro. However, cytokine production remained unchanged, indicating an atypical M2 macrophage. Furthermore, when macrophages were cocultured with lymphocytes, decitabine induced a reduction in the release of inflammatory cytokines such as IL-1β, TNF-α, and IFN-γ, maintaining IL-10 production, suggesting that decitabine could potentialize M2 polarization and might be considered as a therapeutic against the exacerbated immune response.


2014 ◽  
Vol 307 (5) ◽  
pp. H762-H772 ◽  
Author(s):  
Princess Urbina ◽  
Dinender K. Singla

The main objective of this study was to determine whether or not monocyte infiltration occurs in the prediabetic (PD) heart and its role in PD cardiomyopathy. We hypothesized that the PD heart is significantly populated with monocytes and that bone morphogenetic protein (BMP)-7, a novel mediator of monocyte polarization, activates infiltrated monocytes into anti-inflammatory M2 macrophages, thereby inhibiting apoptosis and fibrosis and improving cardiac function. C57Bl6 mice were assigned to control, PD, or PD + BMP-7 groups. PD and PD + BMP-7 groups were administered streptozotocin (50 mg/kg), whereas control animals received sodium citrate buffer. Afterward, the PD + BMP-7 group was administered BMP-7 (200 μg/kg) for 3 days. Our data showed significantly increased infiltrated monocytes and associated pro-inflammatory cytokines, adverse cardiac remodeling, and heart dysfunction in the PD group ( P < 0.05). Interestingly, M2 macrophage differentiation and associated anti-inflammatory cytokines were enhanced and there were reduced adverse cardiac remodeling and improved cardiac function in the PD + BMP-7 group ( P < 0.05). In conclusion, our data suggest that PD cardiomyopathy is associated with increased monocyte infiltration and released proinflammatory cytokines, which contributes to adverse cardiac remodeling and cardiac dysfunction. Moreover, we report that BMP-7 possesses novel therapeutic potential in its ability to differentiate monocytes into M2 macrophages and confer cardiac protection in the PD heart.


2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengang Zhang ◽  
Pei Zhao ◽  
Aihua Li ◽  
Xiaolei Lv ◽  
Yang Gao ◽  
...  

Excessive immune activation and inflammatory mediators may play a critical role in the pathogenesis of chronic heart failure. Methotrexate is a commonly used anti-inflammatory and immunosuppressive drug. In this study, we used a rat model of cardiac myosin-induced experimental autoimmune myocarditis to investigate the effects of low-dose methotrexate (0.1 mg/kg/d for 30 d) on the plasma level of cytokines and cardiac remodeling and function. Our study showed that levels of tumor necrosis factor-(TNF-)alpha and interleukin-6 (IL-6) are significantly increased in postmyocarditis rats, compared with the control rats. Methotrexate treatment reduced the plasma levels of TNF-alpha and IL-6 and increased IL-10 level, compared to saline treatment. In addition, postmyocarditis rats showed significant cardiac fibrosis characterized by increased myocardial collagen volume fraction, perivascular collagen area, and the ratio of collagen type I to type III, compared with the control rats. However, MTX treatment not only markedly attenuated cardiac fibrosis, diminished the left ventricular end-diastolic dimension, but also increased the left ventricular ejection fraction and fractional shortening. Collectively, these results suggest that low-dose methotrexate has ability to regulate inflammatory responses and improves cardiac function and hence contributes to prevent the development of postmyocarditis dilated cardiomyopathy.


2021 ◽  
Vol 22 (11) ◽  
pp. 5480
Author(s):  
David Schumacher ◽  
Adelina Curaj ◽  
Sakine Simsekyilmaz ◽  
Andreas Schober ◽  
Elisa A. Liehn ◽  
...  

Myocardial infarction remains the most common cause of heart failure with adverse remodeling. MicroRNA (miR)155 is upregulated following myocardial infarction and represents a relevant regulatory factor for cardiac remodeling by engagement in cardiac inflammation, fibrosis and cardiomyocyte hypertrophy. Here, we investigated the role of miR155 in cardiac remodeling and dysfunction following myocardial infarction in a dyslipidemic mouse model. Myocardial infarction was induced in dyslipidemic apolipoprotein E-deficient (ApoE−/−) mice with and without additional miR155 knockout by ligation of the LAD. Four weeks later, echocardiography was performed to assess left ventricular (LV) dimensions and function, and mice were subsequently sacrificed for histological analysis. Echocardiography revealed no difference in LV ejection fractions, LV mass and LV volumes between ApoE−/− and ApoE−/−/miR155−/− mice. Histology confirmed comparable infarction size and unaltered neoangiogenesis in the myocardial scar. Notably, myofibroblast density was significantly decreased in ApoE−/−/miR155−/− mice compared to the control, but no difference was observed for total collagen deposition. Our findings reveal that genetic depletion of miR155 in a dyslipidemic mouse model of myocardial infarction does not reduce infarction size and consecutive heart failure but does decrease myofibroblast density in the post-ischemic scar.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2355-2355
Author(s):  
Xia Shao ◽  
Boting Wu ◽  
Pu Chen ◽  
Yanxia Zhan ◽  
Feng Li ◽  
...  

Background: Primary immune thrombocytopenia (ITP) is an acquired autoimmune hemorrhagic disorder, characterized by immune-mediated platelet destruction and impaired megakaryocyte maturation. Although impaired T cells have been implicated to participate in the pathogenesis of ITP, another immune cell signified as M2 macrophages has not been investigated properly in ITP patients. This study aimed to investigate the role of M2 macrophage subsets in primary immune thrombocytopenia (ITP). Methods: Peripheral blood mononuclear cells (PBMC) from newly diagnosed ITP patients and healthy controls (HC) were isolated. M2-like macrophages (CD68+CD163+) and M2 macrophages (CX3CR1+CD163+) were measured by flow cytometry. The correlation between CD68+CD163+ cells and CX3CR1+CD163+ cells was also analyzed. The CX3CR1+cells were sorted by magnetic bead, CD68+CD163+ in PBMC of ITP patients and healthy controls were then isolated, and the proportion of m2-like macrophages before and after the sorting was analyzed. The PPAR gamma and arg-1 levels of mRNAs and proteins of CX3CR1+ M2 macrophages were examined by Real-time PCR and Western Blot, respectively. Results: CX3CR1+CD163+M2 macrophages were positively correlated with CD68+ CD163+ M2-like macrophages in ITP patients (r = 0.54, p < 0.01). After magnetic bead separation, the proportion of CD68+CD163+ cells in CX3CR1+ cells was significantly increased (p = 0.02). Compared with HC, both the mRNA and protein levels of arg-1 of CX3CR1+ M2 macrophages were significantly increased in patients with ITP. The expression level of PPAR gamma protein was significantly increased in ITP than that of HC. However no statistical difference was detected at mRNA expression level, although it was numerically higher in ITP patients than in HC ( p = 0.19). Conclusion: The peripheral CX3CR1+ M2 macrophage exercises similar phenotypes and functions of M2 macrophage. The remarkably increased expression of arg-1 at both transcription and protein levels and PPAR gamma at protein level of CX3CR1+M2 macrophages in ITP patients suggests potential immunomodulatory functions of these macrophage subsets during ITP pathogenesis. However, no significant change at mRNA level of PPAR gamma indicating that the increased PPAR gamma protein level might be caused by other mechanisms, such as after transcription abnormalities, which warrants further investigation. Disclosures No relevant conflicts of interest to declare.


2018 ◽  
Vol 33 (2) ◽  
pp. 70-76 ◽  
Author(s):  
A. E. Gombozhapova ◽  
Yu. V. Rogovskaya ◽  
M. S. Rebenkova ◽  
J. G. Kzhyshkowska ◽  
V. V. Ryabov

Purpose. Myocardial regeneration is one of the most ambitious goals in prevention of adverse cardiac remodeling. Macrophages play a key role in transition from inflammatory to regenerative phase during wound healing following myocardial infarction (MI). We have accumulated data on macrophage properties ex vivo and in cell culture. However, there is no clear information about phenotypic heterogeneity of cardiac macrophages in patients with MI. The purpose of the project was to assess cardiac macrophage infiltration during wound healing following myocardial infarction in clinical settings taking into consideration experimental knowledge.Material and Methods. The study included 41 patients with fatal MI type 1. In addition to routine analysis, macrophages infiltration was assessed by immunohistochemistry. We used CD68 as a marker for the cells of the macrophage lineage, while CD163, CD206, and stabilin-1 were considered as M2 macrophage biomarkers. Nine patients who died from noncardiovascular causes comprised the control group.Results. The intensity of cardiac macrophage infiltration was higher during the regenerative phase than during the inflammatory phase. Results of immunohistochemical analysis demonstrated the presence of phenotypic heterogeneity of cardiac macrophages in patients with MI. We noticed that numbers of CD68+, CD163+, CD206+, and stabilin-1+ macrophages depended on MI phase.Conclusion. Our study supports prospects for implementation of macrophage phenotyping in clinic practice. Improved understanding of phenotypic heterogeneity might become the basis of a method to predict adverse cardiac remodeling and the first step in developing myocardial regeneration target therapy.


2021 ◽  
Vol 35 ◽  
pp. 205873842110167
Author(s):  
Zhensen Zhu ◽  
Bo Chen ◽  
Liang Peng ◽  
Songying Gao ◽  
Jingdong Guo ◽  
...  

Activated M2 macrophages are involved in hypertrophic scar (HS) formation via manipulating the differentiation of fibroblasts to myofibroblasts having the proliferative capacity and biological function. However, the function of exosomes derived from M2 macrophages in HS formation is unclear. Thus, this study aims to investigate the role of exosomes derived by M2 in the formation of HS. To understand the effect of exosomes derived from M2 macrophages on formation of HS, M2 macrophages were co-cultured with human dermal fibroblast (HDF) cells. Cell Counting Kit-8 assay was performed to evaluate HDF proliferation. To evaluate the migration and invasion of HDFs, wound-healing and transwell invasion assays were performed, respectively. To investigate the interaction between LINC01605 and miR-493-3p, a dual-luciferase reporter gene assay was adopted; consequently, an interaction between miR-493-3p and AKT1 was detected. Our results demonstrated that exosomes derived from M2 macrophages promoted the proliferation, migration, and invasion of HDFs. Additionally, we found that long noncoding RNA LINC01605, enriched in exosomes derived from M2 macrophages, promoted fibrosis of HDFs and that GW4869, an inhibitor of exosomes, could revert this effect. Mechanistically, LINC01605 promoted fibrosis of HDFs by directly inhibiting the secretion of miR-493-3p, and miR-493-3p down-regulated the expression of AKT1. Exosomes derived from M2 macrophages promote the proliferation and migration of HDFs by transmitting LINC01605, which may activate the AKT signaling pathway by sponging miR-493-3p. Our results provide a novel approach and basis for further investigation of the function of M2 macrophages in HS formation.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5006
Author(s):  
Pema Raj ◽  
Karen Sayfee ◽  
Mihir Parikh ◽  
Liping Yu ◽  
Jeffrey Wigle ◽  
...  

The development and progression of heart failure (HF) due to myocardial infarction (MI) is a major concern even with current optimal therapy. Resveratrol is a plant polyphenol with cardioprotective properties. Sacubitril/valsartan is known to be beneficial in chronic HF patients. In this study, we investigated the comparative and combinatorial benefits of resveratrol with sacubitril/valsartan alongside an active comparator valsartan in MI-induced male Sprague Dawley rats. MI-induced and sham-operated animals received vehicle, resveratrol, sacubitril/valsartan, valsartan alone or sacubitril/valsartan + resveratrol for 8 weeks. Echocardiography was performed at the endpoint to assess cardiac structure and function. Cardiac oxidative stress, inflammation, fibrosis, brain natriuretic peptide (BNP), creatinine and neutrophil gelatinase associated lipocalin were measured. Treatment with resveratrol, sacubitril/valsartan, valsartan and sacubitril/valsartan + resveratrol significantly prevented left ventricular (LV) dilatation and improved LV ejection fraction in MI-induced rats. All treatments also significantly reduced myocardial tissue oxidative stress, inflammation and fibrosis, as well as BNP. Treatment with the combination of sacubitril/valsartan and resveratrol did not show additive effects. In conclusion, resveratrol, sacubitril/valsartan, and valsartan significantly prevented cardiac remodeling and dysfunction in MI-induced rats. The reduction in cardiac remodeling and dysfunction in MI-induced rats was mediated by a reduction in cardiac oxidative stress, inflammation and fibrosis.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Carmen M. Sandoval Pacheco ◽  
Gabriela V. Araujo Flores ◽  
Kadir Gonzalez ◽  
Claudia M. de Castro Gomes ◽  
Luiz F. D. Passero ◽  
...  

Macrophages play important roles in the innate and acquired immune responses against Leishmania parasites. Depending on the subset and activation status, macrophages may eliminate intracellular parasites; however, these host cells also can offer a safe environment for Leishmania replication. In this sense, the fate of the parasite may be influenced by the phenotype of the infected macrophage, linked to the subtype of classically activated (M1) or alternatively activated (M2) macrophages. In the present study, M1 and M2 macrophage subsets were analyzed by double-staining immunohistochemistry in skin biopsies from patients with American cutaneous leishmaniasis (ACL) caused by L. (L.) amazonensis, L. (V.) braziliensis, L. (V.) panamensis ,and L. (L.) infantum chagasi. High number of M1 macrophages was detected in nonulcerated cutaneous leishmaniasis (NUCL) caused by L. (L.) infantum chagasi ( M 1 = 112 ± 12 , M 2 = 43 ± 12 cells/mm2). On the other side, high density of M2 macrophages was observed in the skin lesions of patients with anergic diffuse cutaneous leishmaniasis (ADCL) ( M 1 = 195 ± 25 , M 2 = 616 ± 114 ), followed by cases of localized cutaneous leishmaniasis (LCL) caused by L. (L.) amazonensis ( M 1 = 97 ± 24 , M 2 = 219 ± 29 ), L. (V.) panamensis ( M 1 = 71 ± 14 , M 2 = 164 ± 14 ), and L. (V.) braziliensis ( M 1 = 50 ± 13 , M 2 = 53 ± 10 ); however, low density of M2 macrophages was observed in NUCL. The data presented herein show the polarization of macrophages in skin lesions caused by different Leishmania species that may be related with the outcome of the disease.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Wenbo Zhao ◽  
Junxian Hu ◽  
Qingyi He

Abstract Background When multicystic vesicles (precursors of exosomes) are formed in cells, there are two results. One is decomposition by lysosomes, and the other is the generation of exosomes that are transported out through the transmembrane. On the other hand, M2 macrophages promote the formation of local vascularization and provide necessary support for the repair of bone defects. To provide a new idea for the treatment of bone defects, the purpose of our study was to investigate the effect of WKYMVm (Trp-Lys-Tyr-Met-Val-D-Met-NH2) peptide on the secretion of exosomes from murine bone marrow-derived MSCs (mBMSCs) and the effect of exosomes on the polarization of M2 macrophages. Methods The WKYMVm peptide was used to activate the formyl peptide receptor 2 (FPR2) pathway in mBMSCs. First, we used Cell Counting Kit-8 (CCK-8) to detect the cytotoxic effect of WKYMVm peptide on mBMSCs. Second, we used western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) to detect the expression of interferon stimulated gene 15 (ISG15) and transcription factor EB (TFEB) in mBMSCs. Then, we detected lysosomal activity using a lysozyme activity assay kit. Third, we used an exosome extraction kit and western blotting to detect the content of exosomes secreted by mBMSCs. Fourth, we used immunofluorescence and western blotting to count the number of polarized M2 macrophages. Finally, we used an inhibitor to block miRNA-146 in exosomes secreted by mBMSCs and counted the number of polarized M2 macrophages. Results We first found that the WKYMVm peptide had no toxic effect on mBMSCs at a concentration of 1 μmol/L. Second, we found that when the FPR2 pathway was activated by the WKYMVm peptide in mBMSCs, ISG15 and TFEB expression was decreased, leading to increased secretion of exosomes. We also found that lysosomal activity was decreased when the FPR2 pathway was activated by the WKYMVm peptide in mBMSCs. Third, we demonstrated that exosomes secreted by mBMSCs promote the polarization of M2 macrophages. Moreover, all these effects can be blocked by the WRWWWW (WRW4, H-Trp-Arg-Trp-Trp-Trp-Trp-OH) peptide, an inhibitor of the FPR2 pathway. Finally, we confirmed the effect of miRNA-146 in exosomes secreted by mBMSCs on promoting the polarization of M2 macrophages. Conclusion Our findings demonstrated the potential value of the WKYMVm peptide in promoting the secretion of exosomes by mBMSCs and eventually leading to M2 macrophage polarization. We believe that our study could provide a research basis for the clinical treatment of bone defects.


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