Project description:Mononuclear phagocytes promote injury and repair following myocardial infarction but discriminating functions within mixed populations remains challenging. We utilized fate mapping and single cell RNA-sequencing to delineate fate specification trajectories of heterogeneous cardiac macrophage subpopulations. In steady state, TIMD4 expression tracked with a dominant resident cardiac macrophage subset that persisted via in situ self-renewal with minimal monocyte input. Following ischemic injury, monocytes displayed significant plasticity, ultimately adopting transcriptional states similar to resident macrophages, but also multiple unique states. Ischemic injury reduced resident macrophage abundance within infarct tissue, and despite transcriptional similarity, TIMD4 expression distinguished resident from recruited macrophages. Specific lineage-based depletion of resident cardiac macrophages resulted in depressed cardiac function and adverse remodeling primarily within the peri-infarct zone, the only region of the myocardium where resident macrophages expanded numerically following injury. Together, these data highlight a non-redundant, cardioprotective role of resident cardiac macrophages, and the diverse transcriptional fates recruited monocytes can adopt.
Project description:Macrophages promote both injury and repair after myocardial infarction, but discriminating functions within mixed populations remains challenging. Here we used fate mapping, parabiosis and single-cell transcriptomics to demonstrate that at steady state, TIMD4+LYVE1+MHC-IIloCCR2- resident cardiac macrophages self-renew with negligible blood monocyte input. Monocytes partially replaced resident TIMD4-LYVE1-MHC-IIhiCCR2- macrophages and fully replaced TIMD4-LYVE1-MHC-IIhiCCR2+ macrophages, revealing a hierarchy of monocyte contribution to functionally distinct macrophage subsets. Ischemic injury reduced TIMD4+ and TIMD4- resident macrophage abundance, whereas CCR2+ monocyte-derived macrophages adopted multiple cell fates within infarcted tissue, including those nearly indistinguishable from resident macrophages. Recruited macrophages did not express TIMD4, highlighting the ability of TIMD4 to track a subset of resident macrophages in the absence of fate mapping. Despite this similarity, inducible depletion of resident macrophages using a Cx3cr1-based system led to impaired cardiac function and promoted adverse remodeling primarily within the peri-infarct zone, revealing a nonredundant, cardioprotective role of resident cardiac macrophages.
Project description:We report that ablation of the serotonin 2B receptor in periostin-expressing cells improves cardiac structure and function following myocardial infarction. We isolated PDGFRa expressing cells during the fibrotic healing phase after injury, and show that these cells have alterations in the expression of genes controlling cell cycle progression as well as a few markers of cell adhesion and migration.
Project description:Patients with acute myocardial infarction (a condition classified under coronary heart disease, including STEMI and NSTEMI) are at high risk for recurrent ischemic events, but the pathways and factors which contribute to this elevated risk are incompletely understood. This study aims to identify biomarkers associated with acute myocardial infarction through various omics strategies. For the identified biomarkers, we aim to demonstrate prognostic value, and predict/stratify the risks of adverse cardiovascular events (e.g., stroke, heart failure, death).
Project description:Affymetrix microarray analysis of molecular changes after myocardial infarction. Samples of heart tissue were analyzed after myocardial infarction from WT and reg3beta knock-out mice. Samples from scar tissue and samples adjacent to the scar were analyzed. In the experiment we primarily compared infarction zone of wild-type to infarction zone of knock-out animals, and remote zone of wild-type to remote zone of knock-outs.
Project description:The outcome of cardiac repair post myocardial infarction is highly dependent on the balance between inflammation and fibrosis, which can lead to adverse ventricular remodeling and failure or early cardiac rupture. In order to profile the dynamic response of the interstitium to cardiac ischemic injury, we performed unbiased single cell RNA Sequencing (scRNAseq) on cardiac interstitial cells at homeostasis and 1, 3, 5, 7, 14, 28 days post-injury using transgenic mice on C57bl/6j background (B6), expressing ZsGreen under the control of the epicardial marker Wt1 (Wt1Cre;RosaZsgreenf/+). About 38,600 cells were captured using the 10xChromium technology. To gain insights on how cell composition and transcriptome can affect the predisposition to cardiac rupture, we compared the data on B6 background with 129S1/SvlmJ (129) mice sham and d3 post-MI (time point proceeding the rupture), capturing about 13,000 additional cells.
Project description:We studied new microRNAs involved in the left ventricular adverse remodeling (LVAR) process after the ST elevation myocardial infarction (STEMI). We analyzed the expression of miRNAs in peripheral blood mononuclear cells (PBMCs) isolated from a group of non-LVAR (n = 5) and LVAR STEMI patients (n = 5), before (0 hour) and after a primary percutaneous coronary intervention (PPCI; 6 hours).