Expression data from mouse optic nerve and optic tract
Ontology highlight
ABSTRACT: A membrane protein SIRPα (CD172a) interacts with another membrane protein CD47 and thereby constitutes a cell–cell contact signal. To investigate the functional role of CD47-SIRPα signal in the brain, we analyzed the effect of genetic ablation of CD47-SIRPα signal on the gene expression profile in specific brain regions by the use of microarrays.
Project description:A membrane protein SIRPα (CD172a) interacts with another membrane protein CD47 and thereby constitutes a cell–cell contact signal. To investigate the functional role of CD47-SIRPα signal in the brain, we analyzed the effect of genetic ablation of CD47-SIRPα signal on the gene expression profile in specific brain cells by the use of microarrays.
Project description:Signal regulatory protein alpha (SIRPα, designated CD172a), also called SHPS-1 (SHP substrate 1) binds to CD47, a receptor for Thromobospondin-1 (TSP1). To block CD47-SIRP interaction, several CD47 blocking agents are in clinical trials. The purpose of this project is to explore the effects of SIRPFc signaling on bCSCs (breast cancer stem cells) derived from MDA-MB- 231 cells, when bCSCs were treated with either SIRPFc or CD47 blocking antibody CC90002 from Celgene Corporation.
Project description:Type-2 innate lymphoid cells (ILC2) are part of a growing family of innate lymphocytes known for their crucial role in both the development and exacerbation of allergic asthma. In this study, we aim to elucidate the critical role of the suppressor molecule signal regulatory protein alpha (SIRPα), which interacts with CD47, in controlling ILC2-mediated airway hyperreactivity (AHR). Our data indicate that activated ILC2s upregulate the expression of SIRPα, and the interaction between SIRPα and CD47 effectively suppresses both ILC2 proliferation and effector function. To evaluate the efficacy of SIRPα in regulating ILC2-mediated AHR, we utilized SIRPα and CD47 deficient mice in a murine model of allergen-induced AHR. Our findings suggest that the absence of SIRPα leads to the overactivation of ILC2s. Conversely, engagement with SIRPα reduces ILC2 cytokine production and effectively regulates ILC2-dependent AHR. Furthermore, the SIRPα-CD47 axis modulates mitochondrial metabolism through the JAK/STAT and ERK/MAPK signaling pathways, thereby regulating NF-κB activity and the production of type two cytokines. Additionally, our studies on human cells have revealed that SIRPα is inducible and expressed on human ILC2s, and administration of a SIRPα agonist effectively suppresses the effector function and cytokine production of ILC2s. Moreover, administering human CD47-Fc to humanized ILC2 mice effectively alleviated AHR and lung inflammation. These findings highlight the promising therapeutic potential of targeting the SIRPα-CD47 axis in the treatment of ILC2-dependent allergic asthma.
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: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:Innate immune checkpoint has emerging as a highly potential target for cancer immunotherapy in recent years. The CD47-SIRPα axis is the best-studied innate checkpoint in cancer. However, the transcription profile of tumor cell duiring CD47-SIRPα blockade therapy remains unclear.
Project description:Necroptosis contributes to hepatocyte death (HC) in non-alcoholic steatohepatitis (NASH), but the fate and roles of necroptotic hepatocytes (necHCs) in NASH remain unknown. We show here that the accumulation of necHCs is associated with worsening NASH in humans and in mice with diet-induced NASH and that NASH liver showed evidence of impaired necHC clearance by liver macrophages. Further, the "don't-eat-me" ligand CD47 on HCs and its receptor, SIRPα, on liver macrophages, were markedly upregulated in human and mouse NASH. In vitro, anti-CD47 or anti-SIRPα promoted necHC engulfment by primary liver macrophages. In a proof-of-concept mouse model of inducible HC necroptosis, anti-CD47 increased necHC uptake by liver macrophages and inhibited hepatic stellate cell (HSC) activation, which is responsible for liver fibrogenesis. Most importantly, treatment of two mouse models of diet-induced NASH with anti-CD47 or anti-SIRPα increased the uptake of necHC by liver macrophages and decreased HSC activation and liver fibrosis. These findings provide evidence that impaired clearance of necHCs by liver macrophages due to CD47-SIRPα upregulation contributes to fibrotic NASH and suggest therapeutic blockade of the CD47-SIRPα axis as a strategy to decrease the accumulation of necHCs in NASH liver and dampen the progression of hepatic fibrosis.
Project description:Type I interferons (IFN-Is) have been well recognized for their roles in immune cells in tumor immunotherapy. However, their direct effects on tumor cells are less understood. Oxidative phosphorylation (OXPHOS) is typically latent in tumor cells. However, whether OXPHOS can be targeted for immunotherapy remains unclear. Here, we found that tumor cell responsiveness to IFN-Is is essential for CD47-SIRPα blockade immunotherapy. Interestingly, IFN-Is directly reprogram tumor cell metabolism by activating OXPHOS for ATP production via ISG15. ATP extracellular release is also enhanced by IFN-Is via autophagy. Tumor cells with a genetic deficiency in OXPHOS or autophagy were resistant to CD47-SIRPα blockade. ATP released upon CD47-SIRPα blockade primes the anti-tumor T cell response via ATP-P2X7 receptor-mediated dendritic cell activation. Further combination with inhibitors of ATP-degrading ectoenzymes, CD39 and CD73, showed synergistic anti-tumor effects. Together, these data reveal the unrecognized mechanisms of IFN-Is on tumor cell metabolic reprograming in tumor immunotherapy and provide novel strategies harnessing this pathway for enhanced efficacy of CD47-SIRPα blockade.
Project description:Conventional dendritic cells (cDCs) are required for peripheral T cell homeostasis in lymphoid organs, but the molecular mechanism underlying this requirement has remained unclear. We here show that T cell–specific CD47-deficient (Cd47ΔT) mice have a markedly reduced number of T cells in peripheral tissues. Direct interaction of CD47-deficient T cells with cDCs resulted in activation of the latter cells, which in turn induced necroptosis of the former cells. The deficiency and cell death of T cells in Cd47ΔT mice required expression of CD47 or its receptor SIRPα (signal regulatory protein α) on cDCs. The development of CD4+ T helper cell–dependent contact hypersensitivity and inhibition of tumor growth by cytotoxic CD8+ T cells were both markedly impaired in Cd47ΔT mice. CD47 on T cells thus likely prevents their necroptotic cell death initiated by cDCs and thereby promotes T cell survival and function.