Project description:Tissue-resident macrophages such as microglia, Kupffer and Langerhans cells derive from Myb-independent yolk sac (YS) progenitors generated before the emergence of hematopoietic stem cells (HSCs). Myb-independent YS-derived resident macrophages self-renew locally, independently of circulating monocytes and HSCs. In contrast, adult blood monocytes as well as infiltrating, gut and dermal macrophages derive from Myb-dependent HSCs. These findings are derived from the mouse, using gene knock-outs and lineage tracing, but their applicability to human development has not been formally demonstrated. Here we use human induced pluripotent stem cells (iPSCs) as a tool to model human hematopoietic development. By using a CRISPR-Cas9 knock-out strategy we show that human iPSC-derived monocytes/macrophages develop in a MYB-independent, RUNX1 and SPI1 (PU.1)-dependent fashion. This result makes human iPSC-derived macrophages developmentally related to and a good model for MYB-independent tissue-resident macrophages such as alveolar and kidney macrophages, microglia, Kupffer and Langerhans cells.
Project description:Macrophages are hematopoietic cells critical for innate immune defense, but also control organ homeostasis in a tissue-specific manner. Tissue-resident macrophages, therefore, provide a well-defined model to study the impact of ontogeny and microenvironment on chromatin state. Here, we profile the dynamics of four histone modifications across seven tissue-resident macrophage populations, as well as monocytes and neutrophils. We identify 12,743 macrophage-specific enhancers and establish that tissue-resident macrophages have distinct enhancer landscapes. Our work suggests that a combination of tissue and lineage-specific transcription factors form the regulatory networks controlling chromatin specification in tissue-resident macrophages. The environment has the capacity to alter the chromatin landscape of macrophages derived from transplanted adult bone marrow in vivo and even differentiated macrophages are reprogrammed when transferred into a new tissue. Altogether, these data provide a comprehensive view of macrophage regulation and highlight the importance of microenvironment along with pioneer factors in orchestrating macrophage identity and plasticity. 7 tissue-resident macrophage populations were isolated, as well as monocytes and neutrophils, and transcriptome analysis was performed. Experiment was done in duplicates.
Project description:Although classified as hematopoietic cells, tissue-resident macrophages are selfrenewing and maintained independently of adult hematopoiesis. While most macrophages originate from embryonic precursors that seed tissues prior to birth, their exact origin is unknown. Using an in utero macrophage depletion strategy and fatemapping of yolk sac (YS) and fetal liver (FL) hematopoiesis, we found that YS macrophages are the main precursors of microglia, while most other macrophages derive from fetal monocytes. Both YS macrophages and fetal monocytes arise from erythro-myeloid progenitors (EMP) generated in the YS. In the YS, EMP gave rise to macrophages without monocytic intermediates, while EMP seeding the FL upon the establishment of blood circulation acquired c-Myb expression and gave rise to fetal monocytes that then seed embryonic tissues to differentiate into macrophages. Thus, adult tissue-resident macrophages established from HSC-independent embryonic precursors arise from two different developmental programs. 12 samples of progenitors, monocytes or macrophages are analyzed from 2 to 4 replicate. Each replicate derived from at least 5 embryos or adult mice
Project description:Cardiac macrophages are heterogenous in phenotype and functions, which has been associated with differences in their ontogeny. Despite extensive research, our understanding of the precise role of different subsets of macrophages in ischemia/reperfusion injury remains incomplete. We here investigated macrophage lineages and ablated tissue macrophages in homeostasis and after I/R injury in a CSF1R-dependent manner. Genomic deletion of a fms-intronic regulatory element (FIRE) in the Csf1r locus resulted in specific absence of resident homeostatic and antigen-presenting macrophages, without affecting the recruitment of monocyte-derived macrophages to the infarcted heart. Specific absence of homeostatic, monocyte-independent macrophages altered the immune cell crosstalk in response to injury and induced proinflammatory neutrophil polarization, resulting in impaired cardiac remodelling without influencing infarct size. In contrast, continuous CSF1R inhibition led to depletion of both resident and recruited macrophage populations. This augmented adverse remodelling after I/R and led to an increased infarct size and deterioration of cardiac function. In summary, resident macrophages orchestrate inflammatory responses improving cardiac remodelling, while recruited macrophages determine infarct size after I/R injury. These findings attribute distinct beneficial effects to different macrophage populations in the context of myocardial infarction.
Project description:Cardiac macrophages are heterogenous in phenotype and functions, which has been associated with differences in their ontogeny. Despite extensive research, our understanding of the precise role of different subsets of macrophages in ischemia/reperfusion injury remains incomplete. We here investigated macrophage lineages and ablated tissue macrophages in homeostasis and after I/R injury in a CSF1R-dependent manner. Genomic deletion of a fms-intronic regulatory element (FIRE) in the Csf1r locus resulted in specific absence of resident homeostatic and antigen-presenting macrophages, without affecting the recruitment of monocyte-derived macrophages to the infarcted heart. Specific absence of homeostatic, monocyte-independent macrophages altered the immune cell crosstalk in response to injury and induced proinflammatory neutrophil polarization, resulting in impaired cardiac remodelling without influencing infarct size. In contrast, continuous CSF1R inhibition led to depletion of both resident and recruited macrophage populations. This augmented adverse remodelling after I/R and led to an increased infarct size and deterioration of cardiac function. In summary, resident macrophages orchestrate inflammatory responses improving cardiac remodelling, while recruited macrophages determine infarct size after I/R injury. These findings attribute distinct beneficial effects to different macrophage populations in the context of myocardial infarction.
Project description:Macrophages are hematopoietic cells critical for innate immune defense, but also control organ homeostasis in a tissue-specific manner. Tissue-resident macrophages, therefore, provide a well-defined model to study the impact of ontogeny and microenvironment on chromatin state. Here, we profile the dynamics of four histone modifications across seven tissue-resident macrophage populations, as well as monocytes and neutrophils. We identify 12,743 macrophage-specific enhancers and establish that tissue-resident macrophages have distinct enhancer landscapes. Our work suggests that a combination of tissue and lineage-specific transcription factors form the regulatory networks controlling chromatin specification in tissue-resident macrophages. The environment has the capacity to alter the chromatin landscape of macrophages derived from transplanted adult bone marrow in vivo and even differentiated macrophages are reprogramed when transferred into a new tissue. Altogether, these data provide a comprehensive view of macrophage regulation and highlight the importance of microenvironment along with pioneer factors in orchestrating macrophage identity and plasticity.
Project description:Macrophages are hematopoietic cells critical for innate immune defense, but also control organ homeostasis in a tissue-specific manner. Tissue-resident macrophages, therefore, provide a well-defined model to study the impact of ontogeny and microenvironment on chromatin state. Here, we profile the dynamics of four histone modifications across seven tissue-resident macrophage populations, as well as monocytes and neutrophils. We identify 12,743 macrophage-specific enhancers and establish that tissue-resident macrophages have distinct enhancer landscapes. Our work suggests that a combination of tissue and lineage-specific transcription factors form the regulatory networks controlling chromatin specification in tissue-resident macrophages. The environment has the capacity to alter the chromatin landscape of macrophages derived from transplanted adult bone marrow in vivo and even differentiated macrophages are reprogramed when transferred into a new tissue. Altogether, these data provide a comprehensive view of macrophage regulation and highlight the importance of microenvironment along with pioneer factors in orchestrating macrophage identity and plasticity.
Project description:Macrophages are hematopoietic cells critical for innate immune defense, but also control organ homeostasis in a tissue-specific manner. Tissue-resident macrophages, therefore, provide a well-defined model to study the impact of ontogeny and microenvironment on chromatin state. Here, we profile the dynamics of four histone modifications across seven tissue-resident macrophage populations, as well as monocytes and neutrophils. We identify 12,743 macrophage-specific enhancers and establish that tissue-resident macrophages have distinct enhancer landscapes. Our work suggests that a combination of tissue and lineage-specific transcription factors form the regulatory networks controlling chromatin specification in tissue-resident macrophages. The environment has the capacity to alter the chromatin landscape of macrophages derived from transplanted adult bone marrow in vivo and even differentiated macrophages are reprogramed when transferred into a new tissue. Altogether, these data provide a comprehensive view of macrophage regulation and highlight the importance of microenvironment along with pioneer factors in orchestrating macrophage identity and plasticity.
Project description:To understand the ontogeny and longevity of tissue-resident macrophages in nonhuman primates (NHPs), we employ a model of autologous hematopoietic stem progenitor cell (HSPC) transplantation with HSPCs genetically modified to be marked with clonal barcodes, allowing for subsequent analysis of clonal ontogeny.
Project description:To understand the ontogeny and longevity of tissue-resident macrophages in nonhuman primates (NHPs), we employ a model of autologous hematopoietic stem progenitor cell (HSPC) transplantation with HSPCs genetically modified to be marked with clonal barcodes, allowing for subsequent analysis of clonal ontogeny.