Project description:Signaling through the thrombospondin-1 receptor CD47 broadly limits cell and tissue survival of stress, but the molecular mechanisms are incompletely understood. We now show that loss of CD47 permits sustained proliferation of primary murine endothelial cells and enables these cells to spontaneously reprogram to form multipotent embryoid bodies. c-Myc, Klf4, Oct4, and Sox2 expression is elevated in CD47-null endothelial cells, in several tissues of CD47- or thrombospondin-1-null mice, and in a human T cell line lacking CD47. CD47 knockdown acutely increases mRNA levels of c-Myc and other stem cell transcription factors in cells and in vivo, whereas CD47 ligation by thrombospondin-1 suppresses c-Myc expression. The inhibitory effects of increasing CD47 levels can be overcome by maintaining c-Myc expression and are absent in cells with dysregulated c-Myc. Thus, CD47 antagonists enable cell self-renewal and reprogramming by overcoming negative regulation of c-Myc and other stem cell transcription factors. To identify gene expression changes associated with CD47 null cells, we compared the gene expression profile of these cells with WT endothelial cell, CD47 null Embryoid bodies cells and an established Embryonic Stem cell line.
Project description:This SuperSeries is composed of the following subset Series: GSE22127: Expression profiling of small intestine lamina propria dendritic cells GSE22128: Expression profiling of splenic dendritic cells Dendritic cells play a vital role in initiating robust immunity against pathogens as well as maintaining immunological tolerance to self antigens, food antigens and intestinal commensals. However, the intracellular signaling networks that program DCs to become tolerogenic are largely unknown. To address this, we analyzed gene expression profiles using microarray analysis of purified intestinal lamina propria DCs (CD11c+ CD11b+ DCs and CD11c+ CD11b- DCs) and compared it to splenic DCs (CD11c+ DC), from mice. We sought to determine the unique genetic profile of small intestine lamina propria CD11c+ cells compared to splenic CD11c+ cells. We performed a meta-analysis using the expression profiles of Intestinal lamina propria CD11c+ CD11b+ DCs (GSM550122), Intestinal lamina propria CD11c+ CD11b- DCs (GSM550121) and Splenic CD11c+ DCs (GSM550126). This study combined and re-normalized the microarray data from GSE22127 and GSE22128 studies. Refer to individual Series for additional details
Project description:CD47 is a ubiquitous cell surface receptor that limits cell clearance by phagocytes that express its counter-receptor signal-regulatory protein-α and directly regulates T cell immunity by interacting with its inhibitory ligand thrombospondin-1. Murine natural killer (NK) cells express higher levels of CD47 than other lymphocytes, but the role of CD47 in regulating NK cell homeostasis and immune function remains unclear. Cd47-/- mice exhibited depletion of NK precursors in bone marrow, but antisense Cd47 knockdown or gene disruption resulted in a dose dependent accumulation of immature and mature NK cells in spleen. Cd47-/- mice were impaired in controlling chronic Clone-13 lymphocytic choriomeningitis virus (LCMV) infection, which was associated with depletion of splenic NK cells and loss of effector cytokine and interferon response gene expression in Cd47-/- NK cells. These data identify CD47 as a cell-intrinsic and systemic regulator of NK cell homeostasis and NK cell responses to viral infection.
Project description:CD47 is a marker of self and a signaling receptor for thrombospondin-1 that is also a membrane
component of extracellular vesicles (EVs) released by various cell types. Previous studies identified CD47-dependent functional effects of EVs on target cells, mediated by delivery of their RNA contents, and enrichment of specific subsets of coding and noncoding RNAs in CD47+ EVs. Here, transcriptomic analyses of EVs released by human and murine cells revealed CD47-dependent enrichment of capped microRNAs and mRNAs. Knockdown or loss of CD47 in wild type Jurkat T cells or treatment with thrombospondin-1 enhanced levels of specific capped-RNAs released in EVs, and reexpressing CD47 in null cells decreased their levels. Mass spectrometry and co-immunoprecipitation identified specific interactions of CD47 with components of the exportin-1/Ran nuclear export complex and its known cargo proteins and between the CD47 cytoplasmic adapter ubiquilin-1 and the exportin-1/Ran complex. Interaction with CD47 was inhibited following alkylation of exportin-1 at Cys528 by leptomycin B. Leptomycin B treatment increased levels of cap-dependent RNAs and their association with exportin-1 in EVs released from wild type but not CD47-deficient cells. These results indicate that CD47
regulates the trafficking of cap-dependent RNAs to EVs through physical interactions with the exportin-1/Ran transport complex. Within the files, lmj1038 represents the control pulldown from CD47- JinB8 cells whereas lmj1039 is the CD47+ pulldown from wild-type Jurkat cells.
Project description:CD47 is a transmembrane glycoprotein that is ubiquitously expressed in different organs and tissues (Barclay and Van den Berg 2014; Liu, et al. 2017). In the human immune system, CD47 interacts with some integrins, two counter-receptor signal regulator protein (SIRP) family members, and the secreted thrombospondin-1 (TSP1) (Barclay and Van den Berg 2014; Gao, et al. 2016; Kaur, et al. 2013; Oldenborg, et al. 2000). CD47 has two established roles in the immune system. The CD47-SIRPα interaction was identified as a critical innate immune checkpoint, which delivers an antiphagocytic signal to macrophages and inhibits neutrophil cytotoxicity (Martínez- Sanz, et al. 2021). Its interaction with inhibitory SIRPα is a physiological anti-phagocytic “don’t eat me” signal on circulating red blood cells that is co-opted by cancer cells (Matlung, et al. 2017). Many malignant cells overexpress CD47 (Betancur, et al. 2017; Chao, et al. 2011; Jaiswal, et al. 2009; Majeti, et al. 2009; Oronsky, et al. 2020; Petrova, et al. 2017). CD47/SIRPα-targeted therapeutics have been developed to overcome this immune checkpoint for cancer treatment (Kaur, et al. 2020; Matlung, et al. 2017). Secondly, engagement of CD47 on T cells by TSP1 regulates their differentiation and survival (Grimbert, et al. 2006; Lamy, et al. 2007) and inhibits T cell receptor signaling and antigen presentation by dendritic cells (DCs) (Kaur, et al. 2014; Li, et al. 2002; Liu, et al. 2015; Miller, et al. 2013; Soto-Pantoja, et al. 2014; Weng, et al. 2014). TSP1/CD47 signaling has similar inhibitory functions to limit NK cell activation (Kim, et al. 2008; Nath, et al. 2018; Nath, et al. 2019; Schwartz, et al. 2019) and IL1β production by macrophages (Stein, et al. 2016). CD47 is therefore a checkpoint that regulates both innate and adaptive immunity. The recent understanding of CD47 antagonism associated with increased antigen presentation by DCs (Liu, et al. 2016) and natural killer cell cytotoxicity (Nath, et al. 2019) contributes to the heightened interest in CD47 as a therapeutic target (Kaur, et al. 2020).
Project description:Elevated CD47 expression in some cancers is associated with decreased survival and limits phagocytic clearance by engaging its counter-receptor SIRPα, but elevated CD47 mRNA expression in human melanomas is associated with improved survival. Gene expression data suggested that recruitment of natural killer (NK) cells, which highly express CD47, into the tumor microenvironment contribute to this correlation. The CD47 ligand thrombospondin-1 inhibited wildtype but not Cd47-/- murine NK cell proliferation and granzyme B and interferon-γ expression in vitro. Cd47-/- NK cells correspondingly showed augmented effector phenotypes. Although, wildtype and Cd47-/- NK cells were equally effective for killing B16 melanoma cells in vitro, Cd47-/- mice exhibited enhanced B16 tumor growth in vivo. Consistent with the human data, tumor-bearing Cd47-/- mice had decreased splenic NK numbers with impaired effector protein expression and elevated exhaustion markers. A pro-apoptotic signature in Cd47-/- NK cells was associated with stress-mediated elevation of mitochondrial proton leak, increased reactive oxygen species and apoptosis. Gene expression profiling identified CD47-dependent transcriptional responses in in NK cells from tumor-bearing mice that regulate systemic NK activation and exhaustion. Treating wildtype mice with a CD47 antibody that blocks thrombospondin-1 binding delayed tumor growth and was associated with increased NK recruitment and increased granzyme B- and interferon-γ levels in intratumoral NK but not CD8+ T cells. Therefore, CD47 in the tumor microenvironment regulates NK-mediated tumor immunity, and therapeutic blockade enhances NK immune function.
Project description:Signaling through the thrombospondin-1 receptor CD47 broadly limits cell and tissue survival of stress, but the molecular mechanisms are incompletely understood. We now show that loss of CD47 permits sustained proliferation of primary murine endothelial cells and enables these cells to spontaneously reprogram to form multipotent embryoid bodies. c-Myc, Klf4, Oct4, and Sox2 expression is elevated in CD47-null endothelial cells, in several tissues of CD47- or thrombospondin-1-null mice, and in a human T cell line lacking CD47. CD47 knockdown acutely increases mRNA levels of c-Myc and other stem cell transcription factors in cells and in vivo, whereas CD47 ligation by thrombospondin-1 suppresses c-Myc expression. The inhibitory effects of increasing CD47 levels can be overcome by maintaining c-Myc expression and are absent in cells with dysregulated c-Myc. Thus, CD47 antagonists enable cell self-renewal and reprogramming by overcoming negative regulation of c-Myc and other stem cell transcription factors.
Project description:CD47 is the only 5-transmembrane (5-TM) spanning receptor of the immune system. Its extracellular domain (ECD) is a cell surface ‘marker of self’ that binds SIRPα and inhibits macrophage phagocytosis, and cancer immuno-therapy approaches in clinical trials are focused on blocking CD47/SIRPα interaction. Using hydrogen-deuterium exchange we show that CD47’s ECLR architecture, comprised of two extracellular loops and the SWF loop, creates a molecular environment stabilizing the ECD for presentation on the cell surface.
Project description:This experiment compares the transciptional changes in antigen specific murine CD8 T cells (P14 T cells) after exposure in vivo to dendritic cells (DC) pulsed with low dose cognate peptide (1uM KAVYNFATC), high dose cognate peptide (100uM KAVYNFATC) or no antigen. Splenic dendritic cells were freshly isolated, peptide pulsed, washed and then adoptively transferred s.c. to the right footpad of C57BL/6 hosts. After 18h, freshly isolated P14 CD8 T cells were labelled with CMFDA and adoptively transferred iv. Two hours after T cell transfer, anti-L selectin antibody was given iv. At 12 and 24 hours, recipients were sacrificed and The right popliteal LN was harvested at 12 or 24h post T cell transfer and a single cell suspension was created and stained with PE CD4, B220 and CD19 (dump channel). Cells were then sorted on a FacsARIA for being non-doublets, CMFDA positive and dump channel negative.
Project description:Mouse splenic dendritic cells are divided into different subsets based on their phynotype. CD8α+ and CD8α- dendritic cells play different roles against pathogens. Cross-presentation is essential for immune defense against viruses, tumors and intracellular bacteria and CD8α+ DCs are more potent in cross-presentation compared to CD8α- DCs. We used microarrays to detail the global gene expression to analyze the underlying mechanism in CD8α+ dendritic cells cross-presentation Splenic CD8α+ and CD8α- dendritic cells were sorted by flow-cytometer for RNA extraction and hybridization on Affymetrix microarrays. Thirty C57BL/6J mice were sacrified for the splenic cells, splenic DCs were enriched by negtive selection, then CD8α+ and CD8α- dendritic cells were seprated based on CD11c and CD8α markers.