Project description:Myeloid-derived suppressor cells (MDSC) are induced in various situations. Generation of MDSC has been investigated extensively. Several cytokines are involved in regulating MDSC. Cellular microvesicles, which comprise cellular membrane (single lipid bilayer) are involved in the induction of MDSC. Especially, proteins or nucleic acids encapsulated in them or expressed on their surface are thought to play a role in the induction of MDSC. Nevertheless, the role of lipid components remains to be investigated. Our earlier study using WKAH rat revealed that MDSC-like cells can be induced in the rat spleen by intravenous injection of liposomal microparticles. They comprise a single lipid bilayer of approximately 250 nm diameter, with no cellular component. Therefore, they resemble cellular microvesicles, Cells capable of suppressing T cell proliferation were liposome-internalized cells. The cell surface phenotype was class II low/-, CD11b/c+. Nitric oxide was responsible for their suppression. In this study, we showed that they express B7-H3 molecule on their surface, removal of B7-H3 positive cells restored T cell proliferation. Western blot analysis confirmed that they are positive for iNOS and NFkB was activated 4 hr after liposomal injection. These results indicate that these cells in question belongs to a subset of MDSCs. Furthermore, we elucidated that vesicular form of lipid is important for the induction of T cell suppressive function. Based on these data, we concluded that liposomal microparticles can induce B7-H3 positive MDSC in vivo and the vesicular formation of lipid is essential for the induction of MDSC.
Project description:Compared to typical endothelial cells (HUVEC) and splenic macrophages (CD14+CD45+), SLCs have phenotype closer to splenic macrophages.
Project description:The close functional relationship between macrophages and dendritic cells has long been recognised. Here, we have examined the gene expression profiles of splenic macrophages and the splenic resident dendritic cell subsets, and demostrate that macrophages and DC show different gene expression profiles. Further, we show that the DC subsets are closer to one another in gene expression profile than they are to macrophages. We here identify a list of differentially expressed genes between the DC subsets, and between DC and macrophages Splenic macrophages, CD8+ and CD8- cDC were analyzed
Project description:The close functional relationship between macrophages and dendritic cells has long been recognised. Here, we have examined the gene expression profiles of splenic macrophages and the splenic resident dendritic cell subsets, and demostrate that macrophages and DC show different gene expression profiles. Further, we show that the DC subsets are closer to one another in gene expression profile than they are to macrophages. We here identify a list of differentially expressed genes between the DC subsets, and between DC and macrophages
Project description:Hemophagocytes are activated macrophages seen morphologically to have engulfed other hematopoietic cells. Their function is unknown. Attempts to induce these cells in vitro or purify them ex vivo have been unsuccessful. We isolated HPCs and resting splenic macrophages by laser capture microdissection. RNA was isolated from captured cells and microarray performed to compare the activation state of HPCs versus resting splenic macrophages.
Project description:Hemophagocytes are activated macrophages seen morphologically to have engulfed other hematopoietic cells. Their function is unknown. Attempts to induce these cells in vitro or purify them ex vivo have been unsuccessful. We isolated HPCs and resting splenic macrophages by laser capture microdissection. RNA was isolated from captured cells and microarray performed to compare the activation state of HPCs versus resting splenic macrophages. We treated WT mice with PBS or CpG1826 and an IL-10receptor blocking antibody. Cells were captured from splenic touch preps on PEN-coated slides, RNA isolated by WT-Ovation One-Direct Amplification System and assayed on Affymetrix mouse gene ST 1.0 chips.
Project description:To investigate the effect of macrophages on mammary basal cells, we established a macrophage depletion mouse model by clodronate liposome (CL) intraperitoneal injection, and the mammary basal cells were collected by FACS sorting. We then performed RNA-seq analysis on clodronate liposome (CL) treated mammary basal cells compared to control.
Project description:To compare the splenic macrophages between SIRPα-knockout mice and WT mice, we performed a complete transcript profiling of the splenic red pulp macrophages from SIRPα-KO mice compared to WT mice using mRNA microarray as a discovery platform. SIRPα-KO mice and WT mice were kept under the same condition. Macrophages were isolated from spleen red pulp of SIRPα-KO mice and WT mice. RNA was then isolated from the same number of freshly isolated macrophages.
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.