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Plasma circulating extracellular RNAs in left ventricular remodeling post-myocardial infarction

ABSTRACT: Despite substantial declines in mortality following myocardial infarction (MI), subsequent left ventricular remodelling (LVRm) remains a significant long-term complication. Extracellular small non-coding RNAs (exRNAs) have been associated with cardiac inflammation and fibrosis and we hypothesized that they are associated with post-MI LVRm phenotypes. RNA sequencing of exRNAs was performed on plasma samples from patients with “beneficial” (decrease LVESVI ≥20%, n=11) and “adverse” (increase LVESVI ≥15%, n=11) LVRm. Selected differentially expressed exRNAs were validated by RT-qPCR (n=331) and analyzed for their association with LVRm determined by cardiac MRI. Principal components of exRNAs were associated with LVRm phenotypes post-MI; specifically, LV mass, LV ejection fraction, LV end systolic volume index, and fibrosis. We then investigated the temporal regulation and cellular origin of exRNAs in murine and cell models and found that: 1) plasma and tissue miRNA expression was temporally regulated; 2) the majority of the miRNAs were increased acutely in tissue and at sub-acute or chronic time-points in plasma; 3) miRNA expression was cell-specific; and 4) cardiomyocytes release a subset of the identified miRNAs packaged in exosomes into culture media in response to hypoxia/reoxygenation. In conclusion, we find that plasma exRNAs are temporally regulated and are associated with measures of post-MI LVRm.

ORGANISM(S): Homo sapiens

PROVIDER: GSE112690 | GEO | 2019/04/01

REPOSITORIES: GEO

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Project description:Rational: We previously reported evidence of endothelial to mesenchymal transition (EndMT) and fibrosis in mitral valve (MV) leaflets at two to six months post-myocardial infarction (MI) in sheep. The onset of these changes and the mechanism of their instigation are not known. Early modulation of EndMT and fibrosis in MV leaflets may limit the development of ischemic mitral regurgitation (IMR) and heart failure. H Objective: To test the hypothesis that circulating molecules present in plasma within days after MI incite EndMT and fibrotic processes in MV leaflets. Method and Results: Ovine MVs harvested 8-10 days after inferior MI (IMI) showed an increase in MV thickness by histology and onset of EndMT, shown by increased CD31/α-smooth muscle actin (α-SMA)+ cells in post-MI MV leaflets (10.5±6.9%) versus sham (2.6±4%). In vitro, post-MI plasma induced EndMT and pro-fibrotic markers and enhanced migration of primary mitral valve endothelial cells (VECs). In contrast, sham plasma did not, despite the presence of TGFβ2 at levels known to induce EndMT in VECs (2 ng/ml). Analysis of sham versus post-MI plasma using a cytokine array revealed a significant drop in the Wnt signaling antagonist secreted frizzled-related protein 3 (sFRP3) in post-MI plasma compared to sham plasma, which was confirmed by ELISA. Addition of recombinant sFRP3 to post-MI plasma reversed its EndMT-inducing effect on mitral VECs, measured by restored VE-cadherin, reduced α-SMA, and reduced TGFβ1-3 expression. Extracellular signal related kinase 1/2 and SMAD2/3 phosphorylation were increased in mitral VEC by post-MI plasma, and both were blocked by supplementing the post-MI plasma with sFRP3. RNA-seq analysis of mitral VECs exposed to post-MI versus sham plasma for 24 hours showed upregulated forkhead box M1 (FOXM1), a transcription factor previously shown to drive fibrosis. FOXM1 was co-localized with CD31 in MV leaflets obtained from sheep at 8-10 days post-MI, which suggests FOXM1 may be linked to EndMT initiation. Blocking FOXM1 with Siomycin A (Sio A) reduced EndMT and pro-fibrotic transcripts in post-MI plasma treated mitral VECs. Finally, post-MI plasma-induced and TGFβ-induced FOXM1 was downregulated by sFRP3. Conclusions: Reduced sFRP3 in post-MI plasma appears to facilitate the onset of TGFβ-driven EndMT and fibrosis in mitral VECs by increasing the transcription factor FOXM1. Restoring sFRP3 levels and/or inhibiting FOXM1 may provide new strategies to minimize maladaptive changes that occur in the MV due to MI.

Project description:To find which genes were significantly modulated by Valsartan in non-infarcted left ventricle, 4 weeks after coronary artery ligation, and to correlate emerging modulated pathways with histology and cardiac magnetic resonance (CMR) imaging. The goal was to validate the estimation of the systolic dysfunction and of the regions preserved by pharmacological treatment performed with a CMR index. Title of the associated submitted paper: Evaluation of left ventricle function by regional fractional area change (RFAC) in a mouse model of myocardial infarction secondary to Valsartan treatment. Abstract: Purpose: Left ventricle (LV) regional fractional area change (RFAC) measured by cardiac magnetic resonance (CMR) allows the non-invasive localization and quantification of the extent of myocardial infarction (MI), and could be applied to assess the effectiveness of pharmacological or regenerative therapies. Here we investigate the ability of RFAC to identify regional dysfunction and discriminate the effect of pharmacological treatment with valsartan, a selective antagonist of angiotensin II type 1 receptor, in a model of MI. Methods: C57BL/6N mice, undergoing coronary artery ligation, were divided into two groups: untreated (MI) or treated with Valsartan (MI+Val). Sham-operated mice were used as a control. Cardiac dimensions and function were assessed at baseline, 24 hours, 1 and 4 weeks post surgery by CMR and echocardiography. At sacrifice histology and whole-genome gene expression profiling were performed. Results: RFAC was able to detect significant differences between treatment groups whereas the global ejection fraction was not. RFAC showed greater loss of contractility in remote non-infarcted myocardium in MI group than in MI+Val group. Consistently, in the same region MI+Val mice showed reduced myocyte hypertrophy, fibroblast proliferation, and fibrosis and modulation of target genes; in addition, left atrium volumes, appendage length and duct contractility were preserved. Conclusion: In this study, RFAC effectively estimated the degree of systolic dysfunction and discriminated the regions preserved by pharmacological treatment. RFAC index is a promising tool to monitor changes in LV contractility and to assess the effectiveness of therapeutic regimens in clinical settings.

Project description:Aims and introduction: Cardiac fibrosis is the hallmark of cardiac disease, particularly myocardial infarction (MI), and is one of the most prevalent causes of heart failure. MI is intricately linked to inflammation, extracellular matrix (ECM) remodelling, and cardiac fibrosis, however the mechanisms underpinning these events remain poorly understood. We recently identified that ECM1 has potential to play a key role in cardiac wound healing but the cellular origins in the heart and specific mechanisms of ECM1 in fibrosis remain elusive. Therefore, we investigated the spatiotemporal, cell specific, expression profile of ECM1 in the healthy and diseased mouse and human heart and investigate ECM1 dependent human cardiac fibroblast (HuCFb) cell signalling mechanisms. Methods and results: Western blotting, immunohistochemistry (IHC) and mRNA in-situ hybridisation revealed that ECM1 protein expression was significantly upregulated in human ischaemic and dilated heart failure patients, and predominantly localised interstitially to fibrotic, inflammatory, and peri-vascular areas. ECM1 specific analysis of the Litviňuková et al. (2020) single-cell and -nuclei RNA sequencing (sc/snRNAseq) dataset of healthy human hearts, and the Farbehi et al. (2019) scRNAseq dataset of mouse hearts post-MI demonstrated that ECM1 expression originates from fibroblasts, macrophages, and pericytes/vascular mural cells in the heart. Further, we identify that post-MI ECM1 is expressed in a temporal dynamic flux from unactivated fibroblasts in sham-operated mice, to M1 macrophages (M1MΦ) at day-3, and myofibroblasts and M2MΦ at day-7. Phosphoproteomics of ECM1 treated human cardiac fibroblast cells (HuCFb) alongside ECM1 to HuCFb cell surface protein binding pull-down and mass spectrometry, revealed that ECM1 signalling goes via proteins associated with Rho protein signal transduction, cell-cell adhesion, microtubule dynamics, and cell chemotaxis pathways, potentially initiated by ECM1 to CTNND1 binding on the cell surface. Further mechanistic analyses identified that ECM1 inhibits HuCFb cell migration and stimulates inflammatory (IL-6 and IL-1β mRNA expression), fibrotic (TGF-β1, TGF-β2 and Col1a2 mRNA expression), and non-canonical Wnt signalling pathways (Wnt5a mRNA expression and JNK1/2/3 and MYPT1 phosphorylation). Conclusions: This study demonstrates that ECM1 expression originates from macrophages and fibroblasts in the mouse and human heart. ECM1 has significant effects on HuCFb migration, inflammatory, fibrotic, Rho protein, and Wnt5a/non-canonical Wnt signalling pathways. Together, ECM1 plays an important role in cardiac wound healing and may represent a novel mechanism of inflammation-fibrosis crosstalk and progression post-MI.

Project description:BACKGROUND: Heart failure (HF) is one of the leading causes of mortality worldwide. Extracellular vesicles (EVs) including small EVs, or exosomes and their molecular cargo are known to modulate cell to cell communication during multiple cardiac diseases. However, the role of systemic EV biogenesis inhibition in the models of HF is not well documented and remains unclear. METHODS: We investigated the role of circulating exosomes during cardiac dysfunction and remodeling in a mouse transverse aortic constriction (TAC) model of HF. Importantly, we investigate the efficacy of Tipifarnib (Tip), a recently identified exosome biogenesis inhibitor that targets the critical proteins (Rab27a, nSmase2 and Alix) involved in exosome biogenesis for this mouse model of HF. In this study, 10-week-old male mice underwent TAC surgery, were randomly assigned to groups with and without Tip treatment (10 mg/kg three times/week) and monitored for 8 weeks and a comprehensive assessment was conducted through performed echocardiographic, histological, and biochemical studies. RESULTS: TAC significantly elevated circulating plasma exosomes and markedly increased cardiac left ventricular (LV) dysfunction, cardiac hypertrophy, and fibrosis. Furthermore, injection of plasma exosomes from TAC mice induced LV dysfunction and cardiomyocyte hypertrophy in uninjured mice without TAC. On the contrary, treatment of Tip in TAC mice reduced circulating exosomes to baseline and remarkably improved LV functions, hypertrophy, and fibrosis. Tip treatment also drastically altered the miRNA profile of circulating post-TAC exosomes, including miR331-5p which was highly downregulated both in TAC circulating exosomes and in TAC cardiac tissue. Mechanistically, miR331-5p is crucial for inhibiting fibroblast-to-myofibroblast transition by targeting HOXC8, a critical regulator of fibrosis. Tipifarnib treatment in TAC mice upregulated the expression of miR331-5p that acts as potent repressor for one of the fibrotic mechanisms mediated by HOXC8. CONCLUSIONS: Our study underscores the pathological role of exosomes in HF and fibrosis in response to pressure overload. Tipifarnib mediated inhibition of exosome biogenesis and cargo sorting may serve as a viable strategy to prevent progressive cardiac remodeling to HF.

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Plasma circulating extracellular RNAs in left ventricular remodeling post-myocardial infarction

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