Human macrophages are immunoprofiled by pericardial fluid small extracellular vesicles modulating lipid metabolism mechanisms

Background

The incidence and severity of ischemic heart disease (IHD) is exacerbated by coronary artery disease (CAD). Monocytes and macrophages are central to atherosclerosis. Endogenous small extracellular vesicles (sEVs) can shuttle microRNAs and other molecular cargos from cell to cell, mediating expressional and functional response in the recipient cells. Recent evidence supports a role for sEVs in modulating macrophage phenotype. The pericardial fluid (PF) is in direct contact with the epicardium and contain sEVs. We recently showed that human PF-sEVs are capable to modulate cardiovascular cells via microRNA shuttling.

Purpose

This study sought to investigate whether PF-sEVs regulate macrophages, contributing to a specific immunophenotype in CAD patients.

Methods

PF was collected from either CAD patients undergoing coronary bypass surgery (CABG) or non-atherosclerotic patients operated for mitral valve repair (non-CAD control group). sEVs were isolated using size exclusion chromatography and characterised for size (Nanosight tracking analysis; NTA), tetrasapanin content (by Nanoview chips), microRNA content by RNA seq and proteomic analysis. Monocytes from healthy donors were isolated from buffy coats and differentiated into macrophages following established protocols. Macrophages were incubated with either CAD-sEVs or non-CAD sEVs for 24h at 37oC. The cells were collected and processed for mRNA analyses (qRT-PCR) and flow cytometry. Human PF-cells were isolated and analysed to be compared with the in vitro setting. Further bioinformatics were employed to understand functional pathways and validated in PF from patients.

Results

Exposure to CAD-sEVs induces a proinflammatory profile of human macrophages. CAD-sEVs treated macrophages showed a CD36+low, CD206+low CD40+high profile. While non-CAD-sEVs did not statistically differ from PBS nor untouched groups, CAD-sEVs increased the mRNA level of IL1a, IL1b, TNFa and decreased MRC1. Proteomics revealed that PF-sEVs from CAD patients carried higher amounts of pro-inflammatory molecules (ICAM-1 and IL18) compared to NonCAD control. Bioinformatics analysis showed that 861 miRNAs were decreased in the PF-sEVs from CAD patients compared to non-CAD. miRNA targets prediction and pathway analyses reported that clusters of deregulated miRNAs could regulate CD36 and SRB1 which were shown to be decreased in CAD-sEVs treated macrophages. Human PF-cells revealed a reduced expression of CD36 on PF-macrophages.

Conclusions

We demonstrate, for the first time, that sEVs isolated from the PF of CAD patients induce a proinflammatory profile of human macrophages and that target crucial lipid metabolism pathways. These clinically relevant results could drive to decipher improved therapeutics able modulate the epicardial/myocardial immune response in CAD patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Fundation

Human pericardial fluid exosomes regulate macrophage immunophenotype: new prospective for cardiovascular immune response in coronary artery disease

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation (BHF) Project Grant

Background

The incidence and severity of ischemic heart disease(IHD) is exacerbated by coronary artery disease (CAD). Monocytes and macrophages are central to atherosclerosis. Endogenous small extracellular vesicles(sEVs) can shuttle microRNAs and other molecular cargos from cell to cell, mediating expressional and functional response in the recipient cells. Recent evidence supports a role for sEVs in modulating macrophage phenotype. The pericardial fluid(PF) is in direct contact with the epicardium and contain sEVs. We recently showed that human PF-sEVs are capable to modulate cardiovascular cells via microRNA shuttling. Moreover, pericardial cells reportedly cross-talk with the myocardium to regulate immune response to IHD.

Purpose

This study sought to investigate whether PF-sEVs regulate macrophages, contributing to a specific immunophenotype in CAD patients.

Methods

PF was collected from either CAD patients undergoing coronary bypass surgery(CABG) or non-atherosclerotic patients operated for mitral valve repair(non-CAD control group).sEVs were isolated using size exclusion chromatography and characterised for size(Nanosight tracking analysis; NTA), tetrasapanin content(by Nanoview chips),microRNA content by RNA seq and proteomic analysis. Monocytes from healthy donors were isolated from buffy coats and differentiated into macrophages following established protocols. Macrophages were incubated with either CAD-sEVs or non-CAD sEVs for 24h at 37oC.The cells were collected and processed for mRNA analyses(qRT-PCR) and flow cytometry.Conditioned medium from sEVs treated macrophages was used to further analyse downstream effect on T cells.Further bioinformatics were employed to understand functional pathways and validated in PF from patients.

Results

Exposure to CAD-sEVs induces a proinflammatory profile of human macrophages.CAD-sEVs treated macrophages showed a CD36+low,CD206+low,CD40+high profile.While non-CAD-sEVs did not statistically differ from PBS nor untouched groups, CAD-sEVs increased the mRNA level of IL1a,IL1b,TNFa and decreased MRC1.Proteomics revealed that PF-sEVs from CAD patients carried higher amounts of pro-inflammatory molecules(ICAM-1 and IL18)compared to non-CAD control.Bioinformatics analysis showed that 861 miRNAs were decreased and 482 increased in the PF-sEVs from CAD patients compared to non-CAD.miRNA targets prediction and pathway analyses reported that clusters of deregulated miRNAs could regulate CD36 and SRB1 which were shown to be decreased in CAD-sEVs treated macrophages.In addition,media from CAD-sEVs treated macrophages induced a higher T cell activation profile.

Conclusions

We demonstrate, for the first time, that sEVs isolated from the PF of CAD patients induce a proinflammatory profile of human macrophages and that target crucial lipid metabolism pathways.These clinically relevant results could drive to decipher improved therapeutics able modulate the epicardial/myocardial immune response in CAD patients

Human pericardial fluid exosomes regulate macrophage immunophenotype: new prospective for cardiovascular myocardium-epicardium crosstalk in coronary artery disease

Background

The incidence and severity of ischemic heart disease (IHD) is exacerbated by coronary artery disease (CAD). Monocytes and macrophages are central to atherosclerosis. Endogenous small extracellular vesicles (sEVs) can shuttle microRNAs and other molecular cargos from cell to cell, mediating expressional and functional response in the recipient cells. Recent evidence supports a role for sEVs in modulating macrophage phenotype. The pericardial fluid (PF) is in direct contact with the epicardium and contain sEVs of myocardial origin (C. Beltrami et.al 2017). We recently showed that human PF-sEVs are capable to modulate cardiovascular cells via microRNA shuttling (C.Beltrami et.al. 2017). Moreover, epicardial cells reportedly cross-talk with the myocardium to regulate immune response to IHD (V.Ramjee et.al 2017).

Purpose

This study sought to investigate whether PF-sEVs regulate macrophages, contributing to a specific immunophenotypes in CAD patients.

Methods

PF was collected from either CAD patients undergoing coronary bypass surgery (CABG) or non-atherosclerotic patients operated for mitral valve repair (non-CAD control group). sEVs were isolated using size exclusion chromatography and characterised for size (Nanosight tracking analysis; NTA) and microRNA content (Exiqon miR-array). Monocytes from healthy donors were isolated from buffy coats and differentiated into macrophages following established protocols. Macrophages were incubated with either CAD-sEVs or non-CAD sEVs for 24h at 37oC. PBS and sEV-free serum were used as negative controls and LPS as a proinflammatory control. The cells were collected and processed for mRNA analyses (qRT-PCR) and Flow cytometry (FACS).

Results

Twenty-four-hour exposure to CAD-sEVs induces a proinflammatory profile of human macrophages. While non-CAD-sEVs did not statistically differ from PBS nor Exo-free groups, CAD-sEVs increased the mRNA level of IL1a, NOS3, TNFa, CCL2 and IL6 (comparison to both non-CAD and negative controls). These data were not associated with changes in apoptosis. Bioinformatics analysis showed that 11 miRNAs where consistently increased, and 67 miRNAs decreased in the PF-sEVs from all CAD patients compared to non-CAD. miRNA targets prediction and pathway analyses (R-Project) revealed that the deregulated miRNAs could regulate macrophage motility and cytokine signalling.

Conclusions

We demonstrate, for the first time, that sEVs isolated from the PF of CAD patients induce a proinflammatory profile of human macrophages. These clinically relevant results could drive to decipher improved therapeutics able to modulate the epicardial/myocardial immune response in CAD patients.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Biritish Heart Fundation grant to Prof. Costanza Emanueli

Leptin signal transduction underlies the differential metabolic response of LEW and WKY rats to cafeteria diet

Although the effect of genetic background on obesity-related phenotypes is well established, the main objective of this study is to determine the phenotypic responses to cafeteria diet (CAF) of two genetically distinct inbred rat strains and give insight into the molecular mechanisms that might be underlying. Lewis (LEW) and Wistar-Kyoto (WKY) rats were fed with either a standard or a CAF diet. The effects of the diet and the strain in the body weight gain, food intake, respiratory quotient, biochemical parameters in plasma as well as in the expression of genes that regulate leptin signalling were determined. Whereas CAF diet promoted weight gain in LEW and WKY rats, as consequence of increased energy intake, metabolic management of this energy surplus was significantly affected by genetic background. LEW and WKY showed a different metabolic profile, LEW rats showed hyperglycaemia, hypertriglyceridemia and high FFA levels, ketogenesis, high adiposity index and inflammation, but WKY did not. Leptin signalling, and specifically the LepRb-mediated regulation of STAT3 activation and Socs3 gene expression in the hypothalamus were inversely modulated by the CAF diet in LEW (upregulated) and WKY rats (downregulated). In the present study, we show evidence of gene-environment interactions in obesity exerted by differential phenotypic responses to CAF diet between LEW and WKY rats. Specifically, we found the leptin-signalling pathway as a divergent point between the strain-specific adaptations to diet.