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Chen H, Zhang Y, Shen Y, Jiang L, Zhang G, Zhang X, Xu Y, Fu F. Deficiency of N-linked glycosylation impairs immune function of B7-H6. Front Immunol 2023; 14:1255667. [PMID: 38035117 PMCID: PMC10684670 DOI: 10.3389/fimmu.2023.1255667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 10/25/2023] [Indexed: 12/02/2023] Open
Abstract
B7-H6 is a novel immune checkpoint molecule that triggers NK cell cytotoxicity, but the role of N-glycosylation in B7-H6 is poorly understood. We here identified the existence of N-glycosylation of B7-H6 in different cell lines and exogenous expression cells by PNGase F digestion and tunicamycin blockage. Subsequently, we demonstrated that B7-H6 contains 6 functional N-linked glycosylation sites by single site mutation and electrophoresis. Phylogenetical and structural analysis revealed that N43 and N208 glycan are conserved in jawed vertebrates and may thus contribute more to the biological functions. We further demonstrated that N43 and N208 glycosylation are essential for B7-H6 to trigger NK cell activation. Mechanistically, we found that N43 and N208 glycan contributed to the stability and membrane expression of B7-H6 protein. Lack of N208 glycosylation led to membrane B7-H6 shedding, while N43 mutation resulted in impaired B7-H6/NKp30 binding affinity. Together, our findings highlight the significance of N-linked glycosylation in B7-H6 biological functions and suggest potential targets for modulating NK cell-mediated immunity.
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Affiliation(s)
- Hanqing Chen
- Jiangsu Institute of Clinical Immunology, the First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Hematology, the First affiliated Hospital of Soochow University, Suzhou, China
| | - Yang Zhang
- Department of Respiratory and Critical Medicine, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Nanjing, China
| | - Yu Shen
- Jiangsu Institute of Clinical Immunology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Liang Jiang
- Suzhou Red Cross Blood Center, Suzhou, China
| | - Guangbo Zhang
- Jiangsu Institute of Clinical Immunology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xueguang Zhang
- Jiangsu Institute of Clinical Immunology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yang Xu
- Department of Hematology, the First affiliated Hospital of Soochow University, Suzhou, China
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Fengqing Fu
- Jiangsu Institute of Clinical Immunology, the First Affiliated Hospital of Soochow University, Suzhou, China
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Kalousková B, Skořepa O, Cmunt D, Abreu C, Krejčová K, Bláha J, Sieglová I, Král V, Fábry M, Pola R, Pechar M, Vaněk O. Tumor Marker B7-H6 Bound to the Coiled Coil Peptide-Polymer Conjugate Enables Targeted Therapy by Activating Human Natural Killer Cells. Biomedicines 2021; 9:biomedicines9111597. [PMID: 34829829 PMCID: PMC8615638 DOI: 10.3390/biomedicines9111597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/29/2021] [Accepted: 10/30/2021] [Indexed: 01/02/2023] Open
Abstract
Targeted cancer immunotherapy is a promising tool for restoring immune surveillance and eradicating cancer cells. Hydrophilic polymers modified with coiled coil peptide tags can be used as universal carriers designed for cell-specific delivery of such biologically active proteins. Here, we describe the preparation of pHPMA-based copolymer conjugated with immunologically active protein B7-H6 via complementary coiled coil VAALEKE (peptide E) and VAALKEK (peptide K) sequences. Receptor B7-H6 was described as a binding partner of NKp30, and its expression has been proven for various tumor cell lines. The binding of B7-H6 to NKp30 activates NK cells and results in Fas ligand or granzyme-mediated apoptosis of target tumor cells. In this work, we optimized the expression of coiled coil tagged B7-H6, its ability to bind activating receptor NKp30 has been confirmed by isothermal titration calorimetry, and the binding stoichiometry of prepared chimeric biopolymer has been characterized by analytical ultracentrifugation. Furthermore, this coiled coil B7-H6-loaded polymer conjugate activates NK cells in vitro and, in combination with coiled coil scFv, enables their targeting towards a model tumor cell line. Prepared chimeric biopolymer represents a promising precursor for targeted cancer immunotherapy by activating the cytotoxic activity of natural killer cells.
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Affiliation(s)
- Barbora Kalousková
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Ondřej Skořepa
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Denis Cmunt
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Celeste Abreu
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Kateřina Krejčová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Jan Bláha
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
| | - Irena Sieglová
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (I.S.); (V.K.); (M.F.)
| | - Vlastimil Král
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (I.S.); (V.K.); (M.F.)
| | - Milan Fábry
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (I.S.); (V.K.); (M.F.)
| | - Robert Pola
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 16206 Prague, Czech Republic; (R.P.); (M.P.)
| | - Michal Pechar
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 16206 Prague, Czech Republic; (R.P.); (M.P.)
| | - Ondřej Vaněk
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 12840 Prague, Czech Republic; (B.K.); (O.S.); (D.C.); (C.A.); (K.K.); (J.B.)
- Correspondence:
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Pinheiro PF, Justino GC, Marques MM. NKp30 - A prospective target for new cancer immunotherapy strategies. Br J Pharmacol 2020; 177:4563-4580. [PMID: 32737988 PMCID: PMC7520444 DOI: 10.1111/bph.15222] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/23/2020] [Accepted: 07/27/2020] [Indexed: 12/16/2022] Open
Abstract
Natural killer (NK) cells are an important arm of the innate immune system. They constitutively express the NKp30 receptor. NKp30-mediated responses are triggered by the binding of specific ligands e.g. tumour cell-derived B7-H6 and involve the secretion of cytotoxic mediators including TNF-α, IFN-γ, perforins and granzymes. The latter two constitute a target cell-directed response that is critical in the process of immunosurveillance. The structure of NKp30 is presented, focusing on the ligand-binding site, on the ligand-induced structural changes and on the experimental data available correlating structure and binding affinity. The translation of NKp30 structural changes to disease progression is also reviewed. NKp30 role in immunotherapy has been explored in chimeric antigen receptor T-cell (CAR-T) therapy. However, antibodies or small ligands targeting NKp30 have not yet been developed. The data reviewed herein unveil the key structural aspects that must be considered for drug design in order to develop novel immunotherapy approaches.
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Affiliation(s)
- Pedro F. Pinheiro
- Centro de Química Estrutural, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
| | - Gonçalo C. Justino
- Centro de Química Estrutural, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
| | - M. Matilde Marques
- Centro de Química Estrutural, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
- Departamento de Engenharia Química, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
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Natural Killer Cell Activation Receptor NKp30 Oligomerization Depends on Its N-Glycosylation. Cancers (Basel) 2020; 12:cancers12071998. [PMID: 32708305 PMCID: PMC7409301 DOI: 10.3390/cancers12071998] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/22/2020] [Accepted: 07/14/2020] [Indexed: 12/29/2022] Open
Abstract
NKp30 is one of the main human natural killer (NK) cell activating receptors used in directed immunotherapy. The oligomerization of the NKp30 ligand binding domain depends on the length of the C-terminal stalk region, but our structural knowledge of NKp30 oligomerization and its role in signal transduction remains limited. Moreover, ligand binding of NKp30 is affected by the presence and type of N-glycosylation. In this study, we assessed whether NKp30 oligomerization depends on its N-glycosylation. Our results show that NKp30 forms oligomers when expressed in HEK293S GnTI- cell lines with simple N-glycans. However, NKp30 was detected only as monomers after enzymatic deglycosylation. Furthermore, we characterized the interaction between NKp30 and its best-studied cognate ligand, B7-H6, with respect to glycosylation and oligomerization, and we solved the crystal structure of this complex with glycosylated NKp30, revealing a new glycosylation-induced mode of NKp30 dimerization. Overall, this study provides new insights into the structural basis of NKp30 oligomerization and explains how the stalk region and glycosylation of NKp30 affect its ligand affinity. This furthers our understanding of the molecular mechanisms involved in NK cell activation, which is crucial for the successful design of novel NK cell-based targeted immunotherapeutics.
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Hassani SN, Rezaeeyan H, Ghodsi A, Saki N. Restoration of natural killer cell cytotoxicity in the suppressive tumor microenvironment: novel approaches to treat AML. J Hematop 2017. [DOI: 10.1007/s12308-017-0306-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Reconstitution of a ligand-binding competent murine NKp30 receptor. Immunogenetics 2017; 70:185-194. [PMID: 28782088 DOI: 10.1007/s00251-017-1025-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/25/2017] [Indexed: 10/19/2022]
Abstract
The activating natural cytotoxicity receptors on natural killer (NK) cells play a fundamental role in immunosurveillance of infections and cancer. Phylogenetic analyses showed that NKp30 is highly conserved in almost all jawed vertebrates and thus, represents one of the most ancient NK cell receptors. However, in contrast to other higher vertebrates, NKp30 is only a pseudogene in mouse, which contains two premature stop codons. To decipher the evolutionary role and biological function of NKp30 in mouse, we removed these premature stop codons and expressed the putative mouse NKp30 (mNKp30) protein as soluble Fc fusion construct and as full-length receptor on A5-GFP reporter cells. Interestingly, even though both NKp30 variants were expressed, maturation and targeting to the plasma membrane were impaired. Previous studies implicated that N-linked glycosylation is crucial for plasma membrane targeting and ligand binding of human NKp30. However, even though present in all other jawed vertebrates analyzed so far, these three N-linked glycosylation sites are missing in mouse NKp30. Interestingly, reconstitution of N-linked glycosylation enabled secretion of a mNKp30-Fc fusion protein which recognized a yet unknown ligand on the plasma membrane of mastocytoma cells. Based on these data, our study is the first to show expression and functional analysis of a mNKp30 protein suggesting that the mouse NKp30 pseudogene is the result of a species-specific loss of function.
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Pazina T, Shemesh A, Brusilovsky M, Porgador A, Campbell KS. Regulation of the Functions of Natural Cytotoxicity Receptors by Interactions with Diverse Ligands and Alterations in Splice Variant Expression. Front Immunol 2017; 8:369. [PMID: 28424697 PMCID: PMC5371597 DOI: 10.3389/fimmu.2017.00369] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/14/2017] [Indexed: 12/11/2022] Open
Abstract
The natural cytotoxicity receptor (NCR) family is constituted by NKp46, NKp44, and NKp30 in humans, which are expressed mainly on natural killer (NK) cells and are encoded by the ncr1, ncr2, and ncr3 genes, respectively. NCRs have classically been defined as activating receptors that trigger cytotoxicity and cytokine responses by NK cells upon engaging with ligands on tumor cells. Several new findings, however, have challenged this model and identified alternative mechanisms regulating the function of NCRs. Recent reports indicate that ligand matters, since the interaction of NKp44 with distinct ligands on target cells can either activate or inhibit NK cells. Also, the NCRs have been found to interact with distinct specificities to various heparan sulfate glycosaminoglycans, which are complex polysaccharides found in extracellular matrix or on cell surface heparan sulfate proteoglycans (HSPGs). The NCRs can engage with HSPGs in trans as a co-ligand on the target cells or in cis on the NK cell surface to regulate receptor–ligand interactions and NK cell activation. A number of splice variants of ncr2 and ncr3 have also been identified, and a predominant expression of certain variants results in inhibitory signaling through NKp44 and NKp30. Several recent studies have found that the selective expression of some of these inhibitory splice variants can significantly influence outcome in the contexts of cancer, infection, and pregnancy. These findings establish that NCR functions are more diverse than originally thought, and better understanding of their splice variant expression profiles and ligand interactions are needed to establish their functional regulation in the context of human health.
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Affiliation(s)
- Tatiana Pazina
- Blood Cell Development and Function Program, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA, USA.,Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", St. Petersburg, Russia
| | - Avishai Shemesh
- Faculty of Health Sciences, The Shraga Segal Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michael Brusilovsky
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Angel Porgador
- Faculty of Health Sciences, The Shraga Segal Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Kerry S Campbell
- Blood Cell Development and Function Program, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA, USA
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