Single-cell RNA sequencing revealed the transcriptional landscape and heterogeneity of macrophages in the intestinal tissues of WT and RUNX3 macrophage conditional knockout mice.
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ABSTRACT: CD11b+ cell populations, especially macrophages, are highly heterogeneous tissue-resident immune cells in mice and humans. The exact subpopulation and its phenotype remain unknown. Here, we analyzed intestinal CD11b+ cell populations from normal and Runx3 macrophage conditionally deficient mice using scRNA-seq. We found that the transcription factor RUNX3 plays a key role in the entry of inflammatory monocytes into resident macrophages. Decreased resident macrophages and elevated ZFP36 in RUNX3flow/flowlyz2-Cre mice, leading to cytokine and chemokine degradation in colon tissue-resident macrophages. RUNX3 promotes the expression of NR4A1, thereby inducing the differentiation of inflammatory monocytes into resident macrophages. Single-cell population analysis revealed that the ERK1/2/MAPK pathway plays a key role in NR4A1-mediated gut-resident macrophage differentiation.
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:Macrophage population in most mammalian organs consists of cells of different origin, with the exception of the central nervous system and the liver, where macrophages of monocytic origin are almost completely absent. The reasons for such distribution and the phenomenon of coexistence of the two separate macrophage lineages with different origin in mammals remain poorly understood. In present study we compared Kupffer cells and monocytes by the immunophenotype, gene expression profile, proteome and pool of mircoRNA. Observed differences do not allow to consider the resident liver macrophages as purely M2 macrophages or monocytes have purely M1 features. Two populations of macrophages of monocytic origin and resident macrophages have fundamentally different roles in maintaining homeostasis. Monocytic macrophages are involved in the regulation of inflammation, and resident macrophages are involved in the regulation of specific organ functions (nitrogen metabolism, complement system protein synthesis). However, if other indicators would be considered as markers of macrophage activity, it is worth noting that Kupffer cells possess some features of M2 macrophages. This is indicated by their expression profile of let-7b/c/d/e miRNAs, a high content of proteins associated with oxidative phosphorylation, as well as an increased level of synthesis of Arg1, IL10.
Project description:Neovascular AMD (nAMD) causes vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Cx3cr1-/- mice display non-classical monocyte and microglia alterations, and increased CNV size, suggesting that non-classical monocytes may inhibit CNV formation. While Nr4a1-/- mice are deficient in non-classical monocytes, results are confounded by macrophage hyper-activation. Nr4a1se2/se2 mice lack a transcriptional activator, resulting in non-classical monocyte loss, without macrophage hyper-activation. We subjected Nr4a1-/- and Nr4a1se2/se2 mice to the laser-induced CNV model and performed multi-parameter flow cytometry. We found that both models lack non-classical monocytes, but only Nr4a1-/- mice displayed increased CNV area. Additionally, CD11c+ macrophages were increased in Nr4a1-/- mice. Single-cell transcriptomic analysis uncovered that CD11c+ macrophages were enriched from Nr4a1-/- mice and expressed a pro-angiogenic transcriptomic profile that was disparate from prior reports of macrophage hyper-activation. These results suggest that non-classical monocytes are dispensable during laser-induced CNV, and NR4A1 deficiency shifts the transcriptional profile toward a pro-angiogenic phenotype.
Project description:During synovial tissue homeostasis, both monocyte-derived F4/80int, and self-renewing F4/80hi tissue-resident, macrophage populations were identified. In contrast, in HUPO mice, decreased synovial tissue-resident macrophages preceded chronic arthritis, opened a niche permitting the influx of activated monocytes, which differentiated into F4/80hi macrophages.
Project description:Bacterial lung infections are associated with strong infiltration of CD11b+ myeloid cells, which limit life-threatening disease, but also severely damage lung tissue. In a murine lung infection model with Streptococcus pneumoniae, we found intrinsic upregulation of CD11b on resident alveolar macrophages. Such CD11b expression was associated with transcriptomic and proteomic adaptations by alveolar macrophages, leading to the identification of specific molecules and pathways that depended on CD11b. In the absence of CD11b, the antimicrobial defense of alveolar macrophages was strongly reduced, and the production of neutrophil-recruiting chemokines was more pronounced. Moreover, CD11b expression limited the infection and prevented excessive alveolar damage. In conclusion, our study provides detailed molecular insights into the alveolar macrophage-specific immune response to Streptococcus pneumoniae lung infection and reveals profound CD11b-dependent alterations that are critical for effective antimicrobial immunity, neutrophil recruitment, and prevention of alveolar damage.
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:We compared arginase-1+ macrophages (macrophages were defined by flow cytometry as CD45hi CD11b+ Ly6G-) with arginase-1- brain macrophages following traumatic brain injury (TBI) by isolating these cells from YARG transgenic mice, which express YFP under the arginase-1 promoter. Both cell populations were isolated from YARG brain tissues one day following TBI. We also examined the expression profile of peripheral blood monocytes (monocytes were defined by flow cytometry as CD11bhi F4/80+) from injured YARG mice and from normal YARG mice. Peripheral blood samples were compared to TBI brain macrophages to assess gene expression changes before and after infiltration into the brain. TBI macrophage subsets were identified by using a reporter mouse strain (YARG) that expresses eYFP from an IRES inserted at the 3' end of the gene for arginase-1 (Arg1), a hallmark of alternatively activated (M2) macrophages. One day after TBI, 21±1.5% of ipsilateral brain macrophages expressed relatively high levels of Arg1 as detected by YFP. Gene expression analysis of Arg1+ and Arg1- brain macrophage populations revealed that these populations were distinct from either classically activated (M1) macrophages or M2 macrophages, with features of both. The Arg1+ cells differed from Arg1- cells in multiple aspects, most notably in their chemokine repertoires. Thus, the macrophage response to TBI involves recruitment of at least two major macrophage subsets. Overall, our data indicate that the macrophage response to TBI is heterogeneous and unique. Four groups (Arg1- brain macrophages post-TBI, Arg1+ brain macrophages post-TBI, normal blood monocytes, blood monocytes post-TBI) were analyzed. Four replicates of each group were analyzed for a total of 16 samples (only 3 replicates of the blood monocyte groups are included in this submission).
Project description:Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor Spic is selectively expressed by RPM and is required for their development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor Bach1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Further, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insight into iron homeostasis. Global gene expression pattern of Spic+ monocytes, Spic- monocytes, and Spic high red pulp macrophages were compared by sorting these cells from Spic(igfp/+) splenocytes and performing microarray-based gene expression profiling. Splenocytes were prepared from Spic(igfp/+) mice and were first negatively selected for CD4, CD8, and B220 by MACS (Miltenyi Biotech) purification using the respective microbeads. Negatively selected splenocytes were then stained with anti-CD11b and anti-Ly6c and sorted for Spic+ monocytes (CD11b+Ly6c+Spic+) and Spic- monocytes (CD11b+Ly6c+Spic-). Purified RPM were obtained by staining splenocytes with anti-F4/80 and sorting for F4/80 hi Spic-EGFP hi cells.
Project description:Objective: Brain tumors (gliomas) contain large populations of infiltrating macrophages and recruited microglia, which in experimental murine glioma models promote tumor formation and progression. Among the barriers to understanding the contributions of these stromal elements to high-grade glioma (glioblastoma; GBM) biology is the relative paucity of tools to characterize infiltrating macrophages and resident microglia. In this study, we leveraged multiple RNA analysis platforms to identify new monocyte markers relevant to GBM patient outcome. Methods: High-confidence lists of mouse resident microglia- and bone marrow-derived macrophage-specific transcripts were generated using converging RNA-seq and microarray technologies and validated using qRT-PCR and flow cytometry. Expression of select cell surface markers was analyzed in brain-infiltrating macrophages and resident microglia in an induced GBM mouse model, while allogeneic bone marrow transplantation was performed to trace the origins of infiltrating and resident macrophages. Glioma tissue microarrays were examined by immunohistochemistry, and the Gene Expression Omnibus (GEO) database was queried to determine the prognostic value of identified microglia biomarkers in human GBM. Results: We generated a unique catalog of differentially-expressed bone marrow-derived monocyte and resident microglia transcripts, and demonstrated that brain-infiltrating macrophages acquire F11R expression in GBM and following bone-marrow transplantation. Moreover, mononuclear cell F11R expression positively correlates with human high-grade glioma and additionally serves as a biomarker for GBM patient survival, regardless of GBM molecular subtype. Significance: These studies establish F11R as a novel monocyte prognostic marker for GBM critical for defining a subpopulation of stromal cells for future potential therapeutic intervention. Total RNA was isolated from three independently-generated sets of flow sorted bone marrow monocytes (CD11b+ CD45high CD115+ Ly6G- cells) and brainstem microglia (CD11b+ CD45low CD115low Ly6G- cells) for Illumina RNA-Seq, and two additional pools were subsequently generated and submitted for Affymetrix Mouse Exon 1.0ST microarray. Two of the RNA-Seq samples were additionally analyzed by the microarray, for a total of 6 samples (3 monocyte, 3 microglia) in each platform. Data outputs were analyzed by two analysis methods each (RNA-Seq data: ALEXA-Seq and Cufflinks; microarray data: Partek and Aroma). All four lists were merged into a new high-confidence gene list of transcripts that were significantly differentially expressed (DE) in three out of the four analyses. In this dataset, we includeRNA-Seq data obtained from flow sorted mouse bone marrow monocytes and brainstem microglia.
Project description:Objective: Brain tumors (gliomas) contain large populations of infiltrating macrophages and recruited microglia, which in experimental murine glioma models promote tumor formation and progression. Among the barriers to understanding the contributions of these stromal elements to high-grade glioma (glioblastoma; GBM) biology is the relative paucity of tools to characterize infiltrating macrophages and resident microglia. In this study, we leveraged multiple RNA analysis platforms to identify new monocyte markers relevant to GBM patient outcome. Methods: High-confidence lists of mouse resident microglia- and bone marrow-derived macrophage-specific transcripts were generated using converging RNA-seq and microarray technologies and validated using qRT-PCR and flow cytometry. Expression of select cell surface markers was analyzed in brain-infiltrating macrophages and resident microglia in an induced GBM mouse model, while allogeneic bone marrow transplantation was performed to trace the origins of infiltrating and resident macrophages. Glioma tissue microarrays were examined by immunohistochemistry, and the Gene Expression Omnibus (GEO) database was queried to determine the prognostic value of identified microglia biomarkers in human GBM. Results: We generated a unique catalog of differentially-expressed bone marrow-derived monocyte and resident microglia transcripts, and demonstrated that brain-infiltrating macrophages acquire F11R expression in GBM and following bone-marrow transplantation. Moreover, mononuclear cell F11R expression positively correlates with human high-grade glioma and additionally serves as a biomarker for GBM patient survival, regardless of GBM molecular subtype. Significance: These studies establish F11R as a novel monocyte prognostic marker for GBM critical for defining a subpopulation of stromal cells for future potential therapeutic intervention. Total RNA was isolated from three independently-generated sets of flow sorted bone marrow monocytes (CD11b+ CD45high CD115+ Ly6G- cells) and brainstem microglia (CD11b+ CD45low CD115low Ly6G- cells) for Illumina RNA-Seq, and two additional pools were subsequently generated and submitted for Affymetrix Mouse Exon 1.0ST microarray. Two of the RNA-Seq samples were additionally analyzed by the microarray, for a total of 6 samples (3 monocyte, 3 microglia) in each platform. Data outputs were analyzed by two analysis methods each (RNA-Seq data: ALEXA-Seq and Cufflinks; microarray data: Partek and Aroma). All four lists were merged into a new high-confidence gene list of transcripts that were significantly differentially expressed (DE) in three out of the four analyses. In this dataset, we include exon expression data obtained from flow sorted mouse bone marrow monocytes and brainstem microglia.