Project description:Survivors of myocardial infarction are at increased risk for vascular dementia. Neuroinflammation has been implicated in the pathogenesis of vascular dementia, yet little is known about the cellular and molecular mediators of neuroinflammation after myocardial infarction. Using a mouse model of myocardial infarction coupled with flow cytometric analyses and immunohistochemistry, we discovered increased monocyte abundance in the brain after myocardial infarction, which was associated with increases in brain-resident perivascular macrophages and microglia. Myeloid cell recruitment and activation was also observed in post-mortem brains of humans that died after myocardial infarction. Spatial and single cell transcriptomic profiling of brain-resident myeloid cells after experimental myocardial infarction revealed increased expression of monocyte chemoattractant proteins. In parallel, myocardial infarction increased crosstalk between brain-resident myeloid cells and oligodendrocytes, leading to neuroinflammation, white matter injury, and cognitive dysfunction. Inhibition of monocyte recruitment preserved white matter integrity and cognitive function, linking monocytes to neurodegeneration after myocardial infarction. Together, these preclinical and clinical results demonstrate that monocyte infiltration into the brain after myocardial infarction initiate neuropathological events that lead to vascular dementia.
Project description:We demonstrate an age-independent loss of type H bone endothelium in heart failure after myocardial infarction in both mice and in humans. Using single-cell RNA sequencing, we delineate the transcriptional heterogeneity of human bone marrow endothelium showing increased expression of inflammatory genes, including IL1B and MYC, in ischemic heart failure. Endothelial-specific overexpression of MYC was sufficient to induce type H bone endothelial cells, whereas inhibition of NLRP3-dependent IL-1 production partially prevents the post-myocardial infarction loss of type H vasculature in mice.
Project description:We demonstrate an age-independent loss of type H bone endothelium in heart failure after myocardial infarction in both mice and in humans. Using single-cell RNA sequencing, we delineate the transcriptional heterogeneity of human bone marrow endothelium showing increased expression of inflammatory genes, including IL1B and MYC, in ischemic heart failure. Endothelial-specific overexpression of MYC was sufficient to induce type H bone endothelial cells, whereas inhibition of NLRP3-dependent IL-1 production partially prevents the post-myocardial infarction loss of type H vasculature in mice.
Project description:Mesenchymal stem cell-derived extracellular vesicles (EVs) have been shown to promote angiogenesis in the ischemic myocardium. This study examines the difference in vascular density, myocardial perfusion, molecular signaling, and gene expression between normal diet (ND) and high fat diet (HFD) groups at baseline and following intra-myocardial injection of EVs We used GeneChip Gene Arrays for whole-transcriptome analysis between normal diet and high fat diet groups at baseline and following intra-myocardial injection of Evs.
Project description:Small extracellular vesicles (sEVs) play a critical role in cardiac cell therapy by delivering molecular cargo and mediating cellular signaling. Among sEV cargo molecule types, microRNA (miRNA) is particularly potent and highly heterogenous. However, not all miRNAs in sEV are beneficial. Two previous studies utilizing computational modeling identified miR-192-5p and miR-432-5p as potentially deleterious in cardiac function and repair. Here, we show that knocking down miR-192-5p and miR-432-5p in cardiac c-kit+ cell-derived sEVs enhances the therapeutic capabilities of sEVs in vitro and in a rat in vivo model of cardiac ischemia reperfusion. miR-192-5p and miR-432-5p depleted CPC-sEVs enhance cardiac function by reducing fibrosis, enhancing mesenchymal stromal cell-like cell mobilization, and inducing macrophage polarization to the M2 phenotype. Knocking down deleterious miRNAs from sEV could be a promising therapeutic strategy for treatment of chronic myocardial infarction.
Project description:Fidelity of wound healing after myocardial infarction (MI) is an important determinant of subsequent adverse cardiac remodeling and failure. Macrophages derived from infiltrating Ly6Chi blood monocytes are a key component of this healing response; however, the importance of other macrophage populations is unclear. Here, using a variety of in vivo murine models and orthogonal approaches, including surgical myocardial infarction, splenectomy, parabiosis, cell adoptive transfer, lineage tracing and cell tracking, RNA sequencing, and functional characterization, we establish in mice an essential role for splenic CD169+Tim4+ marginal metallophilic macrophages (MMMs) in post-MI wound healing. Splenic CD169+Tim4+ MMMs circulate in blood as Ly6Clow monocytes expressing macrophage markers and help populate CD169+Tim4+CCR2-LYVE1low macrophages in the naïve heart. After acute MI, splenic MMMs augment phagocytosis, CCR3 and CCR4 expression, and robustly mobilize to the heart, resulting in marked expansion of cardiac CD169+Tim4+LyVE1low macrophages with an immunomodulatory and pro-resolving gene signature. These macrophages are obligatory for apoptotic neutrophil clearance, suppression of inflammation, and induction of a reparative macrophage phenotype in the infarcted heart. Splenic MMMs are both necessary and sufficient for post-MI wound healing, and limit late pathological remodeling. Liver X receptor-a agonist-induced expansion of the splenic marginal zone and MMMs during acute MI alleviates inflammation and improves short- and long-term cardiac remodeling. Finally, humans with acute ST-elevation MI also exhibit expansion of circulating CD169+Tim4+ cells, primarily within the intermediate (CD14+CD16+) monocyte population. We conclude that splenic CD169+Tim4+ MMMs are required for pro-resolving and reparative responses after MI and can be manipulated for therapeutic benefit to limit long-term heart failure.
Project description:Canonical roles for macrophages in mediating the fibrotic response after a heart attack (myocardial infarction) include turnover of the extracellular matrix and activation of cardiac fibroblasts to initiate collagen deposition. Here we reveal through studying the functional kinetics of fibrosis during zebrafish heart regeneration and mouse heart repair that macrophages can directly contribute collagen to the forming scar. Unbiased transcriptomics revealed an up-regulation of collagen isoforms in both zebrafish and mouse macrophages following injury. Adoptive transfer of macrophages from collagen-tagged transgenic zebrafish and splenic monocyte-derived macrophages from adult mouse GFPtpz-collagen donors, enhanced scar formation and induced fibrosis, respectively, via cell autonomous production of collagen. In zebrafish, macrophage-specific targeting of collagen 4a binding protein and cognate collagen 4a1 followed by transfer led to significantly reduced scarring in cryo-injured hosts. These findings contrast with the current model of scarring whereby collagen deposition is exclusively attributed to myofibroblasts, and implicate macrophages as direct contributors to fibrosis during heart repair.
Project description:The goals of this study are to compare extracellular vesicles-derived circRNAs-lncRNAs-mRNA(RNA-seq) from the plasma of myocardial infarction patients with cardiac remodeling (C), without cardiac remodeling (NC), and normal healthy people (N). Human plasma was separated by centrifugation at 3,000 rpm for 10 min at room temperature (25°C) within 2 h after blood collection and then centrifuged at 13,000 rpm for 10 min at 4°C to remove debris. Isolated plasma samples were stored at -80°C until use. Extracellular vesicles RNA were isolated by affinity-based binding to spin columns using an exoRNeasy Serum/Plasma kit (Qiagen, Hilden, Germany). RNA libraries were prepared for sequencing using SMARTer Stranded Total RNA-Seq Kit - Pico Input Mammalian. RNA-seq was performed by the Illumina NovaSeq 6000 on a 150-bp paired-end run.
Project description:Endothelial cells-derived extracellular vesicles can promote nerve function in mice with traumatic brain injury. We used snRNAseq to analyze the effects of extracellular vesicles derived from endothelial cells on nerve cells in mice with traumatic brain injury.