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Project description:Induction of the inhibitory Smad, Smad7 serves as a negative feedback mechanism that restrains TGF-b-mediated actions in injured tissues. In inflammatory cells, Smad7 has been suggested to exert both pro-inflammatory actions attributed to inhibition of TGF-b-induced suppression of inflammation, and anti-inflammatory effects due to disruption of the TAK-1/NF-kB system. Myocardial infarction triggers a macrophage-driven inflammatory response that plays a central role in cardiac repair, but also contributes to adverse remodeling and fibrosis. We hypothesized that Smad7 upregulation in infarct macrophages may play a modulatory role in cardiac repair, by restraining effects of TGF-b. To test the hypothesis, we investigated the response of Myeloid cell-specific Smad7 knockout mice (MyS7KO) following myocardial infarction protocols, and we examined the in vitro effects of Smad7 in isolated macrophages. Smad7 was upregulated in a subset of infarct macrophages, peaking 7 days after infarction. Myeloid cell-specific Smad7 loss did not affect baseline macrophage gene expression and had no significant effects on homeostatic functions. Although RNA-seq analysis predicted that, in the absence of Smad7, infarct macrophages may have attenuated activation of inflammatory pathways and suppressed TREM1 signaling, myeloid cell-specific Smad7 loss had no significant effects on ventricular dysfunction, adverse remodeling, scar remodeling and collagen deposition after myocardial infarction. In isolated macrophages, TGF-b attenuated pro-inflammatory cytokine and chemokine expression, modulated synthesis of matrix remodeling genes, and had profound effects on macrophage profile, inducing genes associated with activation of sphingosine-1 phosphate and integrin signaling pathways, and inhibiting cholesterol biosynthesis genes. However, RNA-seq and PCR array experiments showed that Smad7 loss has minimal effects on TGF-b-mediated macrophage responses, restraining synthesis of only a small fraction of TGF-b-induced genes, such as Itga5, Olfml3 and Fabp7. Smad7 absence did not affect the anti-inflammatory actions of TGF-b in TNF-stimulated cells. In conclusion, our findings suggest a limited role for macrophage Smad7 in regulation of post-infarction inflammation and repair, and demonstrate that the anti-inflammatory effects of TGF-b in macrophages are not restrained by endogenous Smad7 induction.
2022-04-29 | GSE189450 | GEO
Project description:Induction of the inhibitory Smad, Smad7 serves as a negative feedback mechanism that restrains TGF-b-mediated actions in injured tissues. In inflammatory cells, Smad7 has been suggested to exert both pro-inflammatory actions attributed to inhibition of TGF-b-induced suppression of inflammation, and anti-inflammatory effects due to disruption of the TAK-1/NF-kB system. Myocardial infarction triggers a macrophage-driven inflammatory response that plays a central role in cardiac repair, but also contributes to adverse remodeling and fibrosis. We hypothesized that Smad7 upregulation in infarct macrophages may play a modulatory role in cardiac repair, by restraining effects of TGF-b. To test the hypothesis, we investigated the response of Myeloid cell-specific Smad7 knockout mice (MyS7KO) following myocardial infarction protocols, and we examined the in vitro effects of Smad7 in isolated macrophages. Smad7 was upregulated in a subset of infarct macrophages, peaking 7 days after infarction. Myeloid cell-specific Smad7 loss did not affect baseline macrophage gene expression and had no significant effects on homeostatic functions. Although RNA-seq analysis predicted that, in the absence of Smad7, infarct macrophages may have attenuated activation of inflammatory pathways and suppressed TREM1 signaling, myeloid cell-specific Smad7 loss had no significant effects on ventricular dysfunction, adverse remodeling, scar remodeling and collagen deposition after myocardial infarction. In isolated macrophages, TGF-b attenuated pro-inflammatory cytokine and chemokine expression, modulated synthesis of matrix remodeling genes, and had profound effects on macrophage profile, inducing genes associated with activation of sphingosine-1 phosphate and integrin signaling pathways, and inhibiting cholesterol biosynthesis genes. However, RNA-seq and PCR array experiments showed that Smad7 loss has minimal effects on TGF-b-mediated macrophage responses, restraining synthesis of only a small fraction of TGF-b-induced genes, such as Itga5, Olfml3 and Fabp7. Smad7 absence did not affect the anti-inflammatory actions of TGF-b in TNF-stimulated cells. In conclusion, our findings suggest a limited role for macrophage Smad7 in regulation of post-infarction inflammation and repair, and demonstrate that the anti-inflammatory effects of TGF-b in macrophages are not restrained by endogenous Smad7 induction.
2022-04-29 | GSE187701 | GEO
Project description:The role of endogenous Smad7 in regulating macrophage phenotype following myocardial infarction
| PRJNA783034 | ENA
Project description:The role of endogenous Smad7 in regulating macrophage phenotype following myocardial infarction [JunLi_MyS7KOinvivo]
| PRJNA777639 | ENA
Project description:The role of endogenous Smad7 in regulating macrophage phenotype following myocardial infarction [JunLi_MyS7KOinvitro]
| PRJNA783040 | ENA
Project description:Macrophages infiltrate the infarcted heart and play a critical role in repair, remodeling and fibrosis. Macrophages sense changes in the extracellular matrix (ECM) environment through Integrins, thus activating signaling pathways that regulate their function. Our data show that av integrin is highly expressed in isolated bone marrow macrophages and is markedly upregulated in response to TGF-β, a growth factor known to be activated in the infarcted heart. Accordingly, we hypothesize that aV integrin induction in infarct macrophages may regulate macrophage phenotype, function and response to key macrophage-activating signals following MI.
2022-12-31 | GSE190868 | GEO
Project description:Macrophages infiltrate the infarcted heart and play a critical role in repair, remodeling and fibrosis. Macrophages sense changes in the extracellular matrix (ECM) environment through Integrins, thus activating signaling pathways that regulate their function. Analysis of our previous RNA sequencing data identified integrin α5 (Itgα5) as one of the most upregulated integrin genes in infarct macrophages. Accordingly, we hypothesized that integrin α5 signaling in infarct macrophages transduces ECM-derived signals, regulating responses critical for repair and remodeling of the infarcted heart.
2022-12-31 | GSE190836 | GEO
Project description:Atherosclerotic animal models show increased recruitment of inflammatory cells to the heart after myocardial infarction (MI), which impacts ventricular function and remodeling.The purpose of this study was to determine whether increased myocardial inflammation after MI also contributes to arrhythmias.MI was created in 3 mouse models: (1) atherosclerotic (apolipoprotein E deficient [ApoE(-/-)] on atherogenic diet, n = 12); (2) acute inflammation (wild-type [WT] given daily lipopolysaccharide [LPS] 10 ?g/day, n = 7); and (3) WT (n = 14). Sham-operated (n = 4) mice also were studied. Four days post-MI, an inflammatory protease-activatable fluorescent probe (Prosense680) was injected intravenously to quantify myocardial inflammation on day 5. Optical mapping with voltage-sensitive dye was performed on day 5 to assess electrophysiology and arrhythmia susceptibility.Inflammatory activity (Prosense680 fluorescence) was increased approximately 2-fold in ApoE+MI and LPS+MI hearts vs WT+MI (P<.05) and 3-fold vs sham (P<.05). ApoE+MI and LPS+MI hearts also had prolonged action potential duration, slowed conduction velocity, and increased susceptibility to pacing-induced arrhythmias (56% and 71% vs 13% for WT+MI and 0% for sham, respectively, P<.05, for ApoE+MI and LPS+MI groups vs both WT+MI and sham). Increased macrophage accumulation in ApoE+MI and LPS+MI hearts was confirmed by immunofluorescence. Macrophages were associated with areas of connexin43 (Cx43) degradation, and a 2-fold decrease in Cx43 expression was found in ApoE+MI vs WT+MI hearts (P<.05). ApoE+MI hearts also had a 3-fold increase in interleukin-1? expression, an inflammatory cytokine known to degrade Cx43.Underlying atherosclerosis exacerbates post-MI electrophysiological remodeling and arrhythmias. LPS+MI hearts fully recapitulate the atherosclerotic phenotype, suggesting myocardial inflammation as a key contributor to post-MI arrhythmia.
| S-EPMC4277908 | biostudies-literature
Project description:Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin growth factor family, well known for its role in the homeostasis of the cardiovascular system. Recently, the human BDNF Val66Met single nucleotide polymorphism has been associated with the increased propensity for arterial thrombosis related to acute myocardial infarction (AMI). Using cardiac magnetic resonance imaging and immunohistochemistry analyses, we showed that homozygous mice carrying the human BDNF Val66Met polymorphism (BDNFMet/Met) undergoing left anterior descending (LAD) coronary artery ligation display an adverse cardiac remodeling compared to wild-type (BDNFVal/Val). Interestingly, we observed a persistent presence of pro-inflammatory M1-like macrophages and a reduced accumulation of reparative-like phenotype macrophages (M2-like) in the infarcted heart of mutant mice. Further qPCR analyses showed that BDNFMet/Met peritoneal macrophages are more pro-inflammatory and have a higher migratory ability compared to BDNFVal/Val ones. Finally, macrophages differentiated from circulating monocytes isolated from BDNFMet/Met patients with coronary heart disease displayed the same pro-inflammatory characteristics of the murine ones. In conclusion, the BDNF Val66Met polymorphism predisposes to adverse cardiac remodeling after myocardial infarction in a mouse model and affects macrophage phenotype in both humans and mice. These results provide a new cellular mechanism by which this human BDNF genetic variant could influence cardiovascular disease.
| S-EPMC7290372 | biostudies-literature
Project description:BackgroundPreclinical data suggest that an acute inflammatory response following myocardial infarction (MI) accelerates systemic atherosclerosis. Using combined positron emission and computed tomography, we investigated whether this phenomenon occurs in humans.Methods and resultsOverall, 40 patients with MI and 40 with stable angina underwent thoracic 18F-fluorodeoxyglucose combined positron emission and computed tomography scan. Radiotracer uptake was measured in aortic atheroma and nonvascular tissue (paraspinal muscle). In 1003 patients enrolled in the Global Registry of Acute Coronary Events, we assessed whether infarct size predicted early (≤30 days) and late (>30 days) recurrent coronary events. Compared with patients with stable angina, patients with MI had higher aortic 18F-fluorodeoxyglucose uptake (tissue-to-background ratio 2.15±0.30 versus 1.84±0.18, P<0.0001) and plasma C-reactive protein concentrations (6.50 [2.00 to 12.75] versus 2.00 [0.50 to 4.00] mg/dL, P=0.0005) despite having similar aortic (P=0.12) and less coronary (P=0.006) atherosclerotic burden and similar paraspinal muscular 18F-fluorodeoxyglucose uptake (P=0.52). Patients with ST-segment elevation MI had larger infarcts (peak plasma troponin 32 300 [10 200 to >50 000] versus 3800 [1000 to 9200] ng/L, P<0.0001) and greater aortic 18F-fluorodeoxyglucose uptake (2.24±0.32 versus 2.02±0.21, P=0.03) than those with non-ST-segment elevation MI. Peak plasma troponin concentrations correlated with aortic 18F-fluorodeoxyglucose uptake (r=0.43, P=0.01) and, on multivariate analysis, independently predicted early (tertile 3 versus tertile 1: relative risk 4.40 [95% CI 1.90 to 10.19], P=0.001), but not late, recurrent MI.ConclusionsThe presence and extent of MI is associated with increased aortic atherosclerotic inflammation and early recurrent MI. This finding supports the hypothesis that acute MI exacerbates systemic atherosclerotic inflammation and remote plaque destabilization: MI begets MI.Clinical trial registrationURL: https://www.clinicaltrials.gov. Unique identifier: NCT01749254.
| S-EPMC4599491 | biostudies-literature