Project description:Cardiac resident MerTK+ macrophages exert multiple protective roles post-ischemic injury. To determine the potential reason for the protective role of MerTK+ cardiac macrophages, microarray was performed to identify gene expression profiles on isolated Trem2+, MHCII+, Lyve1+, and MerTK- macrophages from the heart tissue of WT mice post-IR. We investigated the potential reason for the protective role of MerTK+ cardiac macrophages in myocardial Ischemia reperfusion injuryby microarray.
Project description:Platelets are anucleated blood cells that are produced by their progenitor cell, the megakaryocyte (MK). Platelets are centrally positioned in hemostasis and thrombosis and, according to the recent findings, play key roles in innate immunity, inflammation, atherogenesis, and cancer metastasis. The quantitative and qualitative properties of platelets are crucial determinants of their hemostatic function. While the regulatory mechanisms of platelet number and size have been studied separately, critical questions remain regarding the interplay of platelet number and size in hemostasis. In this study, using a mouse model of irradiation (IR)-induced thrombocytopenia, we show that mature MKs (mMKs) are resistant to IR and maintain the nadir platelet levels post IR. To identify the phenotype switching and function variation in BM MKs post IR, we performed microarray expression profiling of MKs from the bone marrow of mice at 1- or 3-days post IR and control mice (Ctrl).
Project description:Cardiac resident MerTK+ macrophages exert multiple protective roles post-ischemic injury, however, the mechanisms regulating their fate are not fully understood. Here we show that GAS6-inducible transcription factor ATF3 prevents apoptosis of MerTK+ macrophages after ischemia-reperfusion (IR) injury, by repressing the transcription of multiple genes involved in type I interferon expression (Ifih1 and Infb1) and apoptosis (Apaf1). Mice lacking ATF3 in cardiac macrophages or myeloid cells showed excessive loss of MerTK+ cardiac macrophages, poor angiogenesis, and worse heart dysfunction post-IR, which were rescued by the transfer of MerTK+ cardiac macrophages. GAS6 administration improved cardiac repair in an ATF3-dependent manner. Finally, we showed a negative association of GAS6 and ATF3 expression with the risk of major adverse cardiac events in patients with ischemic heart disease. These results indicate that the GAS6-ATF3 axis has a protective role against IR injury by regulating MerTK+ cardiac macrophage survival/proliferation.
Project description:Rats underwent surgery for LAD ligation for 30 min followed by reperfusion. Heart ventricles were collected 2d or 7d after reperfusion. Keywords: rat heart ventricles, LAD - left anterior descending coronary artery, IR - ischemia-reperfusion
Project description:Lysosomes are at the epicenter of cellular processes critical for inflammasome activation in macrophages, including autophagy and lipid metabolism. Inflammasome activation and IL1-beta secretion are implicated in atherogenesis, ischemic cardiac injury and resultant heart failure; however, little is known about the role of macrophage lysosome function in regulating these processes. We hypothesized that macrophages exhibit lysosome dysfunction in heart failure due to ischemic injury, and that augmentation of macrophage lysosomal biogenesis via macrophage-specific overexpression of transcription factor EB (mf-TFEB) would attenuate ischemic remodeling by modulating macrophage inflammatory responses. In both mice subject to ischemia-reperfusion injury, and human heart tissue from patients with ischemic cardiomyopathy, we find evidence of lysosome insufficiency and autophagic impairment, respectively. Mf-TFEB overexpression significantly attenuated post-IR adverse left ventricular remodeling at 4 weeks without affecting scar size. Mf-TFEB overexpression reduced the relative amounts of pro-inflammatory macrophage populations in the myocardium. RNA sequencing of flow-sorted cardiac macrophages post-IR confirmed that TFEB stimulated a lysosomal transcriptional program in macrophages, and upregulated key targets involved in lysosomal lipid metabolism, which we show are critical for inflammasome suppression. Both TFEB-dependent inflammasome suppression and effects on post-IR remodeling were independent of autophagy. Our findings suggest that TFEB reprograms macrophage lysosomal lipid metabolism to attenuate inflammasome activity and protect against post-ischemic cardiac remodeling and simultaneously shift our understanding of how autophagy and lipid metabolism impact acute inflammation.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes 6h post sham- or 1.5 Gy IR-treatmentl was compared to extract IR-related gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients.
Project description:Ly6Clow macrophages promote scar formation and prevent early infarct expansion after myocardial infarction (MI). Although CD4+ T cells influence the regulation of Ly6Clow macrophages after MI, the mechanism remains largely unknown. Here, we focused on IL-21 and uncovered its physiological relevance in post-MI hearts. CD4+ T cells harvested from the infarcted heart produce IL-21 upon stimulation, and IL-21 receptor was expressed on Ly6Clo macrophages in the infarcted heart. The survival rate after MI was significantly improved in IL-21-deficient mice compared with WT mice. Moreover, transcriptome analysis of infarcted heart tissue demonstrated that inflammation was persistent in WT mice compared with IL-21-deficient mice. The number of neutrophils was significantly decreased, whereas the number of Ly6Clow macrophages was significantly increased in IL-21-deficient mice. Consistently, IL-21 enhanced the apoptosis of Ly6Clow macrophages. Furthermore, RNA-seq analysis of Ly6Chi and Ly6Clo macrophages stimulated with or without IL-21 for 24 hours revealed that IL-21 induces inflammatory responses in both Ly6Chi and Ly6Clo macrophages. Finally, the treatment with IL-21 receptor Fc protein significantly increased the survival after MI. Thus, the deletion of IL-21 improves survival after MI by preventing Ly6Clo macrophage apoptosis.
Project description:To investigate whether SPARCL1 affects lung macrophage polarization in vivo RNA sequencing (RNA-seq) of isolated lung macrophages (CD45+Ly6G-CD64+F4/80+) on day 20 post-influenza infection was used to further examine the consequences of EC overexpression of Sparcl1.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes 6h post sham- or 1.5 Gy IR-treatmentl was compared to extract IR-related gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients. Biological replicates: 6 or 4; Technical replicates: 2 with C3 and C5 dye swap.