SIRPα: A key player in innate immunity

Feng, Yongyi; Huang, Chunliu; Wang, Yingzhao; Chen, Jun

doi:10.1002/eji.202350375

Cited by 5 publications

(2 citation statements)

References 99 publications

(118 reference statements)

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“…In addition, CD47-SIRPα interactions were shown to negatively regulate macrophage phagocytosis of iRBCs in murine models, and anti-CD47 treatment was found to significantly increase the clearance of iRBCs ( 32 ). The CD47-SIRPα axis is also known for its implication on monocyte migration, dendritic cell functions, and maturation ( 33 ), suggesting that additional studies are needed to determine the extent to which this axis is involved in the inhibition of phagocytosis. In a recent study, Garcia-Senosian et al.…”

Section: Discussionmentioning

confidence: 99%

Monocytes, particularly nonclassical ones, lose their opsonic and nonopsonic phagocytosis capacity during pediatric cerebral malaria

Vianou,

Royo,

Dechavanne

et al. 2024

Front. Immunol.

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IntroductionInnate immunity is crucial to reducing parasite burden and contributing to survival in severe malaria. Monocytes are key actors in the innate response and, like macrophages, are plastic cells whose function and phenotype are regulated by the signals from the microenvironment. In the context of cerebral malaria (CM), monocyte response constitutes an important issue to understand. We previously demonstrated that decreased percentages of nonclassical monocytes were associated with death outcomes in CM children. In the current study, we postulated that monocyte phagocytosis function is impacted by the severity of malaria infection.MethodsTo study this hypothesis, we compared the opsonic and nonopsonic phagocytosis capacity of circulant monocytes from Beninese children with uncomplicated malaria (UM) and CM. For the CM group, samples were obtained at inclusion (D0) and 3 and 30 days after treatment (D3, D30). The phagocytosis capacity of monocytes and their subsets was characterized by flow cytometry and transcriptional profiling by studying genes known for their functional implication in infected-red blood cell (iRBC) elimination or immune escape.ResultsOur results confirm our hypothesis and highlight the higher capacity of nonclassical monocytes to phagocyte iRBC. We also confirm that a low number of nonclassical monocytes is associated with CM outcome when compared to UM, suggesting a mobilization of this subpopulation to the cerebral inflammatory site. Finally, our results suggest the implication of the inhibitory receptors LILRB1, LILRB2, and Tim3 in phagocytosis control.DiscussionTaken together, these data provide a better understanding of the interplay between monocytes and malaria infection in the pathogenicity of CM.

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Section: Discussionmentioning

confidence: 99%

Monocytes, particularly nonclassical ones, lose their opsonic and nonopsonic phagocytosis capacity during pediatric cerebral malaria

Vianou,

Royo,

Dechavanne

et al. 2024

Front. Immunol.

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“…It binds as a ligand for the signal regulatory protein-alpha (SIRPα) which is expressed in myeloid cells (5), including dendritic cells (DCs) and macrophages (6), as well as in cytotoxic T lymphocytes (7).…”

Section: Introductionmentioning

confidence: 99%

Investigating the role of CD47 gene regulation in Iraqi cancer patients: a promising prognostic factor

Jabbar,

Ismael

2023

Iraqi j. cancer med. genet.

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Background: Innate immune checkpoints have been one of the most studied and promising approaches in cancer immune therapy. Therefore, it is considered valuable when investigating these checkpoints at the gene expression and protein levels. However, this approach still has variations from study to study due to various types of cancer. Therefore, it is hypothesized that CD47 could be one of those checkpoints that affect the survival of cancer cells. CD47 is an integrin like marker that has been identified for its role as “do not eat me signal” which enhances the ability of cancer cells to escape from being phagocytized by macrophages. Aim of the study: This study aims to investigate CD47 expression in ten solid tumors and five blood cancers at the gene level and at the protein level.Methods: Clinical specimens were collected from patients with different cancers attending Kirkuk oncology center. The patients were categorized into two main groups: solid tumor group and blood-derived cancer group together with their control counterparts. CD47 gene expression was investigated using q RT-PCR techniques while its protein levels were investigated using ELISA techniques.Results: The results showed a significant up-regulation of CD47 gene expression in gastric cancer, cholangiocarcinoma; CCA (bile duct), chronic myeloid leukemia (CML), and breast cancer, respectively. These results were also confirmed at the protein level, suggesting that those types of malignancy are more susceptible to an increase in CD47 expression than other types of cancer that were involved in this study. Conclusion: CD47 tends to be over-expressed in solid tumors and blood cancers, and could be used as diagnostic and prognostic markers, especially for solid tumors.

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Signal Regulatory Protein α Expression in Systemic Vasculitis

Banerjee,

Rose,

Panicker

et al. 2024

ACR Open Rheumatology

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ObjectiveSignal regulatory protein α (SIRPα) is found primarily on myeloid cells, including macrophages and neutrophils; binds to CD47; and regulates phagocytosis, antigen presentation, cellular fusion, cell proliferation, and migration. Therefore, SIRPα may be involved in the pathogenesis of autoimmune diseases, including systemic vasculitis. This study aimed to assess SIRPα expression in tissue samples from patients with vasculitis.MethodsImmunohistochemical staining for SIRPα was performed on temporal artery (TA), kidney, and lung biopsy samples from patients with giant cell arteritis (GCA), patients with microscopic polyangiitis (MPA), patients with granulomatosis with polyangiitis (GPA), and patients without vasculitis. A score of SIRPα+ expression was calculated, derived from the percentages of monocytes, macrophages, and dendritic cells and neutrophils with different staining intensities in affected tissues.ResultsA total of 46 samples from patients with different vasculitides (GCA, MPA, and GPA) were included in the study. Tissue samples included TA samples from 15 patients with GCA; kidney samples from 11 and 9 patients with GPA and MPA, respectively; and lung samples from 11 patients with GPA. Most tissue samples from patients with active vasculitis (15 of 15 TA samples, 17 of 20 kidney samples, and 9 of 11 lung samples) showed SIRPα staining. SIRPα staining intensity was less in kidney samples compared to TA and lung samples.ConclusionThis study demonstrates high‐level expression of SIRPα in macrophages and monocytes in affected tissue in systemic vasculitis. These findings provide a foundation for further studies exploring the role of the SIRPα–CD47 pathway in the pathogenesis of systemic vasculitis and the potential for the blockade of SIRPα and/or the depletion of SIRPα+ cells as treatment of systemic vasculitis.

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SIRPα: A key player in innate immunity

Cited by 5 publications

References 99 publications

Monocytes, particularly nonclassical ones, lose their opsonic and nonopsonic phagocytosis capacity during pediatric cerebral malaria

Monocytes, particularly nonclassical ones, lose their opsonic and nonopsonic phagocytosis capacity during pediatric cerebral malaria

Investigating the role of CD47 gene regulation in Iraqi cancer patients: a promising prognostic factor

Signal Regulatory Protein α Expression in Systemic Vasculitis

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