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Experimental Hematology Aug 2019Whether hematopoietic stem cells (HSCs) express lineage markers is controversial. In this study, we highly purified HSCs from the adult bone marrow of C57BL/6 mice and...
Whether hematopoietic stem cells (HSCs) express lineage markers is controversial. In this study, we highly purified HSCs from the adult bone marrow of C57BL/6 mice and examined their gene expression and reconstitution potential. We first focused on the integrin family. Single-cell reverse transcription polymerase chain reaction revealed that the expression of ItgaM/Itgb2 (Mac-1) and Itga2b/Itgb3 (CD41/CD61) gradually increased along HSC differentiation, whereas Itga4, Itga5, Itga6, and ItgaV (CD51) together with Itgb1 were highly expressed in both HSCs and hematopoietic progenitor cells (HPCs). We next fractionated HSCs based on their expression of Mac-1, CD41, and CD51 by flow cytometry. We detected Mac-negative and Mac-low, but not Mac-high cells, in the HSC population. We also detected CD41-negative, -low, and -high cells in the HSC population. Competitive repopulation revealed that Mac-1-negative and -low HSCs were functionally similar, and CD41-negative and -low HSCs were functionally similar, at the single-cell level, but CD41-high HSCs were not detectable. We then found that the selection of Mac-1-negative HSCs or CD41-negative HSCs had no advantage in HSC purification. We moreover found that HSCs expressed more CD51 than CD41, and HPCs expressed more CD41 than CD51, suggesting that CD51 expression was gradually replaced by CD41 expression during megakaryocyte differentiation. We concluded that low levels of Mac-1 and CD41 expression are irrelevant to the self-renewal and differentiation potentials in HSCs.
Topics: Animals; Antigens, CD; Antigens, Differentiation; Bone Marrow Transplantation; Cell Lineage; Cell Self Renewal; Cell Separation; Clone Cells; Flow Cytometry; Gene Expression Regulation; Hematopoiesis; Hematopoietic Stem Cells; Integrins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Radiation Chimera; Thrombopoiesis
PubMed: 31299288
DOI: 10.1016/j.exphem.2019.07.001 -
Clinical and Translational Medicine Aug 2022The CD47-signal regulatory protein alpha (SIRPα) 'don't eat me' signalling axis is perhaps the most prominent innate immune checkpoint to date. However, from initial... (Review)
Review
BACKGROUND
The CD47-signal regulatory protein alpha (SIRPα) 'don't eat me' signalling axis is perhaps the most prominent innate immune checkpoint to date. However, from initial clinical trials, it is evident that monotherapy with CD47-SIRPα blocking has a limited therapeutic effect at the maximum tolerated dose. Furthermore, treatment is associated with severe side effects, most notably anaemia, that are attributable to the ubiquitous expression of CD47. Nevertheless, promising clinical responses have been reported upon combination with the tumour-targeting antibody rituximab or azacytidine, although toxicity issues still hamper clinical application.
MAIN BODY
Here, we discuss the current state of CD47-SIRPα blocking therapy with a focus on limitations of current strategies, such as depletion of red blood cells. Subsequently, we focus on innovations designed to overcome these limitations. These include novel antibody formats designed to selectively target CD47 on tumour cells as well as tumour-targeted bispecific antibodies with improved selectivity. In addition, the rationale and outcome of combinatorial approaches to improve the therapeutic effect of CD47 blockade are discussed. Such combinations include those with tumour-targeted opsonizing antibodies, systemic therapy, epigenetic drugs, other immunomodulatory T-cell-targeted therapeutics or dual immunomodulatory CD47 bispecific antibodies.
CONCLUSION
With these advances in the design of CD47-SIRPα-targeting therapeutic strategies and increasing insight into the mechanism of action of this innate checkpoint, including the role of adaptive immunity, further advances in the clinical application of this checkpoint can be anticipated.
Topics: Antibodies, Bispecific; Antigens, Differentiation; CD47 Antigen; Humans; Immunologic Factors; Immunotherapy; Neoplasms; Phagocytosis; Receptors, Immunologic
PubMed: 35908284
DOI: 10.1002/ctm2.943 -
Aging Dec 2023Response to oncogenic factors like UV, GADD45 family in skin participates in scavenging ROS, DNA repair and cell cycle control. Because of this, the previous study of...
Response to oncogenic factors like UV, GADD45 family in skin participates in scavenging ROS, DNA repair and cell cycle control. Because of this, the previous study of the chronic UVB injury model has found that hsa-miR-300 can conduct intercellular transport by exosomes and target regulation of GADD45B. Whether the hsa-miR-300-GADD45B still regulates tumor development by cell cycle pathway is unclear. Through transcriptomic analysis of primary (n=39) and metastatic (n=102) melanoma, it was confirmed that in metastatic samples, some of the 97 down-regulated genes participate in maintaining skin homeostasis while 42 up-regulated genes were enriched in cancer-related functions. Furthermore, CDKN1A, CDKN2A, CXCR4 and RAD51 in the melanoma pathway, were also differentially expressed between normal skin and melanoma. CDKN1A and CDKN2A were also found to be involved in TP53-dependent cell cycle regulation. In conclusion, it was speculated that CDKN1A, CDKN2A, TP53, GADD45B and hsa-miR-300 may have regulatory relationships. It was demonstrated that there is a bidirectional regulation between hsa-miR-300 and TP53. In addition, miR-300 can regulate CDKN1A by GADD45B/TP53 and promote melanoma growth by accelerating the cell cycle transition from G1/S to G2 phase.
Topics: Humans; Melanoma; Cell Cycle; MicroRNAs; Cell Division; Cell Cycle Checkpoints; GADD45 Proteins; Antigens, Differentiation
PubMed: 38070141
DOI: 10.18632/aging.205276 -
Frontiers in Immunology 2018CD96 represents a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily. CD96 is expressed mainly by cells of hematopoietic origin, in particular... (Review)
Review
CD96 represents a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily. CD96 is expressed mainly by cells of hematopoietic origin, in particular on T and NK cells. Upon interaction with CD155 present on target cells, CD96 was found to inhibit mouse NK cells, and absence of this interaction either by blocking with antibody or knockout of CD96 showed profound beneficial effects in containment of tumors and metastatic spread in murine model systems. However, our knowledge regarding CD96 functions remains fragmentary. In this review, we will discuss structural features of CD96 and their putative impact on function as well as some unresolved issues such as a potential activation that may be conferred by human but not mouse CD96. This is of importance for translation into human cancer therapy. We will also address CD96 activities in the context of the immune regulatory network that consists of CD155, CD96, CD226, and TIGIT.
Topics: Animals; Antigen Presentation; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Biomarkers, Tumor; Gene Expression Regulation; Humans; Immunity; Immunomodulation; Killer Cells, Natural; Molecular Targeted Therapy; Neoplasms; Signal Transduction; Structure-Activity Relationship; T-Lymphocyte Subsets
PubMed: 29868026
DOI: 10.3389/fimmu.2018.01072 -
The Journal of Biological Chemistry Nov 2021CCAAT enhancer binding protein (CEBP) transcription factors (TFs) are known to promote adipocyte differentiation; however, suppressors of CEBP TFs have not been reported...
CCAAT enhancer binding protein (CEBP) transcription factors (TFs) are known to promote adipocyte differentiation; however, suppressors of CEBP TFs have not been reported thus far. Here, we find that homologous chromosome pairing protein 2 (Hop2) functions as an inhibitor for the TF CEBPα. We found that Hop2 mRNA is highly and specifically expressed in adipose tissue, and that ectopic Hop2 expression suppresses reporter activity induced by CEBP as revealed by DNA transfection. Recombinant and ectopically expressed Hop2 was shown to interact with CEBPα in pull-down and coimmunoprecipitation assays, and interaction between endogenous Hop2 and CEBPα was observed in the nuclei of 3T3 preadipocytes and adipocytes by immunofluorescence and coimmunoprecipitation of nuclear extracts. In addition, Hop2 stable overexpression in 3T3 preadipocytes inhibited adipocyte differentiation and adipocyte marker gene expression. These in vitro data suggest that Hop2 inhibits adipogenesis by suppressing CEBP-mediated transactivation. Consistent with a negative role for Hop2 in adipogenesis, ablation of Hop2 (Hop2) in mice led to increased body weight, adipose volume, adipocyte size, and adipogenic marker gene expression. Adipogenic differentiation of isolated adipose-derived mesenchymal stem cells showed a greater number of lipid droplet-containing colonies formed in Hop2 adipose-derived mesenchymal stem cell cultures than in wt controls, which is associated with the increased expression of adipogenic marker genes. Finally, chromatin immunoprecipitation revealed a higher binding activity of endogenous CEBPα to peroxisome proliferator-activated receptor γ, a master adipogenic TF, and a known CEBPα target gene. Therefore, our study identifies for the first time that Hop2 is an intrinsic suppressor of CEBPα and thus adipogenesis in adipocytes.
Topics: 3T3 Cells; Adipocytes; Adipogenesis; Animals; Antigens, Differentiation; CCAAT-Enhancer-Binding Proteins; Cell Cycle Proteins; Cell Differentiation; Gene Expression Regulation; Mice; Mice, Knockout
PubMed: 34600885
DOI: 10.1016/j.jbc.2021.101264 -
The Journal of Experimental Medicine Apr 2015
Review
Topics: Animals; Antigens, Differentiation; Humans; Mice; Monocytes; Portraits as Topic
PubMed: 25847970
DOI: 10.1084/jem.2124insight1 -
Hitting the complexity of the TIGIT-CD96-CD112R-CD226 axis for next-generation cancer immunotherapy.BMB Reports Jan 2021Antibody-based therapeutics targeting the inhibitory receptors PD-1, PD-L1, or CTLA-4 have shown remarkable clinical progress on several cancers. However, most patients... (Review)
Review
Antibody-based therapeutics targeting the inhibitory receptors PD-1, PD-L1, or CTLA-4 have shown remarkable clinical progress on several cancers. However, most patients do not benefit from these therapies. Thus, many efforts are being made to identify new immune checkpoint receptor-ligand pathways that are alternative targets for cancer immunotherapies. Nectin and nectin-like molecules are widely expressed on several types of tumor cells and play regulatory roles in T- and NK-cell functions. TIGIT, CD226, CD96 and CD112R on lymphoid cells are a group of immunoglobulin superfamily receptors that interact with Nectin and nectin-like molecules with different affinities. These receptors transmit activating or inhibitory signals upon binding their cognate ligands to the immune cells. The integrated signals formed by their complex interactions contribute to regulating immune-cell functions. Several clinical trials are currently evaluating the efficacy of anti-TIGIT and anti-CD112R blockades for treating patients with solid tumors. However, many questions still need to be answered in order to fully understand the dynamics and functions of these receptor networks. This review addresses the rationale behind targeting TIGIT, CD226, CD96, and CD112R to regulate T- and NK-cell functions and discusses their potential application in cancer immunotherapy. [BMB Reports 2021; 54(1): 2-11].
Topics: Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Humans; Immunotherapy; Neoplasms; Receptors, Cell Surface; Receptors, Immunologic
PubMed: 33298247
DOI: 10.5483/BMBRep.2021.54.1.229 -
Glycobiology Jul 2017Siglecs are transmembrane sialoglycan binding proteins, most of which are expressed on leukocyte subsets and have inhibitory motifs that translate cell surface ligation...
Siglecs are transmembrane sialoglycan binding proteins, most of which are expressed on leukocyte subsets and have inhibitory motifs that translate cell surface ligation into immune suppression. In humans, Siglec-8 on eosinophils, mast cells and basophils and Siglec-9 on neutrophils, monocytes and some T-cells, mediate immune cell death, inhibition of immune mediator release and/or enhancement of anti-inflammatory mediator release. Endogenous sialoglycan ligands in tissues, mostly uncharacterized, engage siglecs on leukocytes to inhibit inflammation. Glycan array analyses demonstrated that Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E (respectively) have distinct glycan binding specificities, with Siglec-8 more structurally restricted. Since siglecs are involved in lung inflammation, we studied Siglec-8 and Siglec-9 ligands in human lungs and airways. Siglec-8 ligands are in tracheal submucosal glands and cartilage but not airway epithelium or connective tissues, whereas Siglec-9 ligands are broadly distributed. Mouse airways do not have Siglec-8 ligands, whereas Siglec-9 ligands are on airways of both species. Extraction of human airways and lung followed by electrophoretic resolution and siglec blotting revealed Siglec-8 ligands in extracts of human trachea and cultured tracheal gland cells, but not parenchyma or cultured airway epithelial cells whereas Siglec-9 ligands were extracted from all airway and lung tissues and cells tested. Siglec-8 and Siglec-9 ligands in airways appear to be high molecular weight O-linked sialoglycoproteins. These data reveal differential glycan specificities of Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E, and the tissue distributions and molecular characteristics of Siglec-8 and Siglec-9 sialoglycan ligands on human airways and lungs.
Topics: Adult; Antigens, CD; Antigens, Differentiation, B-Lymphocyte; Cells, Cultured; Female; Humans; Lectins; Ligands; Lung; Male; Middle Aged; N-Acetylneuraminic Acid; Polysaccharides; Protein Binding; Respiratory Mucosa; Sialic Acid Binding Immunoglobulin-like Lectins; Trachea
PubMed: 28369504
DOI: 10.1093/glycob/cwx026 -
Journal of Hematology & Oncology Jun 2020Natural killer (NK) cells are powerful immune effectors, modulating their anti-tumor function through a balance activating and inhibitor ligands on their cell surface.... (Review)
Review
Natural killer (NK) cells are powerful immune effectors, modulating their anti-tumor function through a balance activating and inhibitor ligands on their cell surface. Though still emerging, cancer immunotherapies utilizing NK cells are proving promising as a modality for the treatment of a number of solid tumors, including glioblastoma (GBM) and other gliomas, but are often limited due to complex immunosuppression associated with the GBM tumor microenvironment which includes overexpression of inhibitory receptors on GBM cells. CD155, or poliovirus receptor (PVR), has recently emerged as a pro-tumorigenic antigen, overexpressed on GBM and contributing to increased GBM migration and aggressiveness. CD155 has also been established as an immunomodulatory receptor, able to both activate NK cells through interactions with CD226 (DNAM-1) and CD96 and inhibit them through interaction with TIGIT. However, NK cell TIGIT expression has been shown to be upregulated in cancer, establishing CD155 as a predominantly inhibitory receptor within the context of GBM and other solid tumors, and rendering it of interest as a potential target for antigen-specific NK cell-based immunotherapy. This review will explore the function of CD155 within GBM as it relates to tumor migration and NK cell immunoregulation, as well as pre-clinical and clinical targeting of CD155/TIGIT and the potential that this pathway holds for the development of emerging NK cell-based immunotherapies.
Topics: Animals; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Antineoplastic Agents, Immunological; Cell Adhesion; Cell Movement; Glioblastoma; Humans; Immunotherapy; Killer Cells, Natural; Mice; Neoplasm Invasiveness; Neoplasm Metastasis; Oncolytic Virotherapy; Poliovirus; Reassortant Viruses; Receptors, Immunologic; Receptors, Virus; Rhinovirus; Tumor Microenvironment
PubMed: 32532329
DOI: 10.1186/s13045-020-00913-2 -
Biochemical and Biophysical Research... May 2022CD99 is a glycoprotein primarily expressed in immune cells. Physiologically, it is involved in the adhesion, migration, and development of immune cells. The presence of...
CD99 is a glycoprotein primarily expressed in immune cells. Physiologically, it is involved in the adhesion, migration, and development of immune cells. The presence of CD99 in the skin was first reported in 2016 and its function is yet to be determined. In this study, we aimed to understand the role of CD99 in the skin using normal human epidermal keratinocytes (NHEK). CD99 expression increased with the confluency of NHEK, while the CD99-high expressing NHEK lost their stem cell properties and played a role in barrier function. We characterized CD99-expressing NHEK as cells committed to early differentiation because they expressed early differentiation markers. However, the deficiency of CD99 in NHEK disrupted homeostasis and caused aberrant differentiation, as evidenced by larger cells with lesser Ki67 staining and higher expression of terminal differentiation markers. Hence, we propose that CD99 is involved in maintaining homeostasis and initiating early differentiation in the skin.
Topics: 12E7 Antigen; Antigens, Differentiation; Cell Differentiation; Cells, Cultured; Epidermis; Homeostasis; Humans; Keratinocytes
PubMed: 35339749
DOI: 10.1016/j.bbrc.2022.03.087