RESUMEN

The search for new cytotoxic agents capable of lysing tumor cells is an important task in the fight against cancer. Here we have shown that the HspBP1 protein, the chaperone of the heat shock protein Hsp70, is able to form a complex with the previously discovered peptide (17.1) of the innate immunity protein Tag7. Experiments using thermophoresis demonstrated that the affinity of the Tag7 protein peptide 17.1 to the HspBP1 molecule is 100 times higher than that of the full-sized Tag7 molecule. The addition of the 17.1-HspBP1 complex to tumor cells induces apoptosis and necroptosis in them. The results obtained in this work can be used to develop promising antitumor drugs.

Asunto(s)

Receptores Tipo I de Factores de Necrosis Tumoral , Apoptosis , Proteínas HSP70 de Choque Térmico/metabolismo , Inmunidad Innata , Péptidos/farmacología

RESUMEN

In this study, we have found two peptides of Tag7 (PGLYRP1) protein-17.1A (HRDVQRT) and 17.1B (RSNYVLKG), that have different affinities to the TNFR1 receptor and the Hsp70 protein. Peptide 17.1A is able to inhibit signal transduction through the TNFR1 receptor, and peptide 17.1B can activate this receptor in a complex with Hsp70. Thus, it is possible to modulate the activity of the TNFR1 receptor and further perform its specific inhibition or activation in the treatment of various autoimmune or oncological diseases.

Asunto(s)

Citocinas , Neoplasias , Receptores Tipo I de Factores de Necrosis Tumoral , Humanos , Apoptosis , Citocinas/metabolismo , Inmunidad Innata , Péptidos/farmacología , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Factor de Necrosis Tumoral alfa

RESUMEN

To carry out antitumor activity against cells that have lost surface antigens, human lymphocytes must have a certain repertoire of surface proteins capable of contacting a tumor cell and inducing programmed cell death in it. In this work, we showed that activation of healthy donor cells by IL-2 cytokine within 6 days causes the appearance of FasL, CD25, and LFA-1 proteins on CD8+CD25+ T lymphocytes, and also converts the LFA-1 protein into an active form having a high affinity for its target, ICAM-1 integrin. The appearance of these proteins on the surface of this subpopulation of lymphocytes allows them to induce programmed cell death in HLA-negative tumor cells.

Asunto(s)

Interleucina-2 , Antígeno-1 Asociado a Función de Linfocito , Humanos , Apoptosis , Linfocitos T CD8-positivos , Citocinas , Interleucina-2/metabolismo , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Linfocitos T/inmunología

RESUMEN

The pathogenesis of autoimmune arthritis is a hot topic in current research. The main focus of this work was to study cytokines released in CFA-induced arthritis in ICR mice as well as the regulation of blood levels of cytokines by two peptides of the innate immunity protein Tag7 (PGLYRP1) capable of blocking the activation of the TNFR1 receptor. Arthritis was induced by local periarticular single-dose injections of 40 µL of complete Freund's adjuvant (CFA) into the left ankle joints of mice. The levels of chemokines and cytokines in plasma were measured using a Bio-Plex Pro Mouse Cytokine Kit at 3, 10, and 21 days after arthritis induction. Tag7 peptides were shown to decrease the blood levels of the pro-inflammatory cytokines IL-6, TNF, and IL-1ß. Administration of peptides also decreased the levels of chemokines MGSA/CXCL1, MIP-2α/CXCL2, ENA78/CXCL5, MIG/CXCL9, IP-10/CXCL10, MCP-1/CCL2, and RANTES/CCL5. Furthermore, a decrease in the levels of cytokines IL7, G-CSF, and M-CSF was demonstrated. Addition of the studied peptides strongly affected IFN-γ concentration. We believe that a decrease in the levels of cytokine IFN-γ was associated with a therapeutic effect of Tag7 peptides manifested in alleviation of the destruction of cartilage and bone tissues in the CFA-induced arthritis.

Asunto(s)

Artritis Experimental , Artritis , Ratones , Animales , Citocinas/metabolismo , Adyuvante de Freund , Quimiocina CCL5 , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Factor Estimulante de Colonias de Macrófagos , Quimiocina CXCL10 , Interleucina-6 , Quimiocina CXCL2 , Interleucina-7 , Ratones Endogámicos ICR , Inmunidad Innata , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Artritis Experimental/tratamiento farmacológico

RESUMEN

One of the basic features of immune system is the ability to sustain balance between activation and suppression of effector lymphocytes. In this process a key role belongs to the subpopulation of cells called regulatory T cells (Treg). Many cancer and autoimmune diseases are caused by malfunctions of Treg, and investigation of this subpopulation is important for development of new therapeutic approaches. In this study, we demonstrate that regulatory T cells can migrate along the concentration gradient of Tag7-Mts1 complex, and also they produce agents that induce blood cells migration.

Asunto(s)

Neoplasias , Linfocitos T Reguladores , Humanos , Quimiotaxis , Citocinas , Linfocitos

RESUMEN

An investigation of innate immunity receptors sheds light on the mechanisms of inflammation and associated immune reactions. One of the key immune regulators is the TREM-1 receptor, which is involved in both inflammation and antitumor immune response. In this article, we have obtained a new ligand for the TREM-1 receptor. The peptide, named N3, is a part of the innate immune protein PGLYRP1/Tag7. It is responsible for activating the TREM-1 signaling pathway. Here, we have demonstrated that the N3 peptide acts like other TREM-1 receptor ligands: its binding results in a mild inflammation response and appearance of cytotoxic lymphocytes. We have shown that cytotoxic populations of lymphocytes in N3 peptide-treated PBMCs are similar to those treated with Tag7 or Hsp70. We also determined the part of the N3 peptide responsible for binding to TREM-1. The resulting peptide (N9) consists of nine amino acids and can be considered as a potential peptide that blocks TREM-1 signaling.

Asunto(s)

Proteínas Portadoras , Citocinas , Receptor Activador Expresado en Células Mieloides 1 , Proteínas Portadoras/metabolismo , Citocinas/metabolismo , Humanos , Inflamación/metabolismo , Ligandos , Péptidos/metabolismo , Péptidos/farmacología , Receptor Activador Expresado en Células Mieloides 1/metabolismo

RESUMEN

Infection caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in many cases is accompanied by the release of a large amount of proinflammatory cytokines in an event known as "cytokine storm", which is associated with severe coronavirus disease 2019 (COVID-19) cases and high mortality. The excessive production of proinflammatory cytokines is linked, inter alia, to the enhanced activity of receptors capable of recognizing the conservative regions of pathogens and cell debris, namely TLRs, TREM-1 and TNFR1. Here we report that peptides derived from innate immunity protein Tag7 inhibit activation of TREM-1 and TNFR1 receptors during acute inflammation. Peptides from the N-terminal fragment of Tag7 bind only to TREM-1, while peptides from the C-terminal fragment interact solely with TNFR1. Selected peptides are capable of inhibiting the production of proinflammatory cytokines both in peripheral blood mononuclear cells (PBMCs) from healthy donors and in vivo in the mouse model of acute lung injury (ALI) by diffuse alveolar damage (DAD). Treatment with peptides significantly decreases the infiltration of mononuclear cells to lungs in animals with DAD. Our findings suggest that Tag7-derived peptides might be beneficial in terms of the therapy or prevention of acute lung injury, e.g., for treating COVID-19 patients with severe pulmonary lesions.

Asunto(s)

Lesión Pulmonar Aguda/patología , Citocinas/química , Péptidos/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Receptor Activador Expresado en Células Mieloides 1/metabolismo , Lesión Pulmonar Aguda/metabolismo , Animales , Citocinas/genética , Citocinas/metabolismo , Modelos Animales de Enfermedad , Humanos , Interferón gamma/genética , Interferón gamma/metabolismo , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Lipopolisacáridos/farmacología , Pulmón/metabolismo , Pulmón/patología , Activación de Linfocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos ICR , Péptidos/química , Péptidos/farmacología , Unión Proteica , Receptores Tipo I de Factores de Necrosis Tumoral/antagonistas & inhibidores , Receptor Activador Expresado en Células Mieloides 1/antagonistas & inhibidores

RESUMEN

Search for novel regulatory protein fragments with potential functional roles is required both for understanding the immune response mechanisms and the development of targeted immunotherapy. Earlier we demonstrated that the PGLYRP1/Tag7 innate immunity protein can be regarded as an inhibitor of TNFα cytotoxic activity via the interaction with its TNF receptor 1 (TNFR1). A C-terminal peptide fragment 17.1 of the molecule is responsible for this function. In this study we have identified a minimal 8-mer region of this peptide (hereinafter - 17.1A) capable to bind to TNFR1. As a result of such interaction, the cytotoxic signals induced by this receptor are blocked. Also, this peptide demonstrates an anti-inflammatory activity in vivo in the complete Freund's adjuvant (CFA)-induced arthritis model in laboratory mice. Peptide 17.1A is capable to reduce periarticular inflammation, inhibit the development of synovitis and exhibit a protective effect on cartilage and bone tissues. This peptide can turn out to be a promising medicinal agent for autoimmune arthritis and other diseases.

Asunto(s)

Artritis Experimental/metabolismo , Artritis Reumatoide/metabolismo , Citocinas/metabolismo , Fibroblastos/inmunología , Inflamación/inmunología , Péptidos/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Animales , Artritis Experimental/inmunología , Artritis Reumatoide/inmunología , Línea Celular , Citotoxicidad Inmunológica , Modelos Animales de Enfermedad , Femenino , Humanos , Inmunidad Innata , Ratones , Unión Proteica , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

One of the promising fields of modern molecular biology is the search for new proteins that regulate the various stages of the immune response and the investigation of the molecular mechanisms of action of these proteins. Such proteins include the multifunctional protein PGLYRP1/Tag7, belonging to the PGRP-S protein family, whose gene was discovered in mice at the Institute of Gene Biology, Russian Academy of Sciences, in 1996. PGLYRP1/Tag7 is classified as a protein of innate immunity; however, it can also participate in the regulation of acquired immunity mechanisms. In this paper, we consider the involvement of PGLYRP1/Tag7 in the triggering of antimicrobial defense mechanisms and formation of subsets of cytotoxic lymphocytes that kill tumor cells. The paper emphasizes that the multifaceted functional activity of Tag7 in the immune response has to do with its ability to interact with various proteins to form stable protein complexes. Hsp70-associated Tag7 can induce the death of tumor cells carrying the TNFR1 receptor. Tag7, associated with the Mts1 (S100A4) protein, can stimulate the migration of innate and adaptive immune cytotoxic lymphocytes to a lesion site. Involvement of Tag7 in the regulation of immunological processes suggests that it may be considered as a promising agent in cancer therapy. These properties of Tag7 were used to develop autologous vaccines that have passed the first and second phases of clinical trials in patients with end-stage melanoma and renal cancer. The C-terminal peptide of Tag7, isolated by limited proteolysis, was shown to protect the cartilage and bone tissue of the ankle joint in mice with induced autoimmune arthritis and may be a promising drug for suppressing the development of inflammatory processes.

RESUMEN

Investigation of interactions between a pro-inflammatory cytokine tumor necrosis factor (TNFα) and its receptor is required for the development of new treatments for autoimmune diseases associated with the adverse effects of TNFα. Earlier, we demonstrated that the innate immunity protein Tag7 (PGRP-S, PGLYRP1) can interact with the TNFα receptor, TNFR1, and block the transduction of apoptotic signals through this receptor. A complex formed between the Tag7 protein and the major heat shock protein Hsp70 can activate TNFR1 receptor and induce tumor cell death via either apoptotic or necroptotic pathway. In this study, we show that a 12-mer peptide, designated 17.1, which was derived from the Tag7 protein, can be regarded as a novel TNFα inhibitor, also is able to form a cytotoxic complex with the heat shock protein Hsp70. This finding demonstrates a new role for Hsp70 protein in the immune response. Also, this new inhibitory 17.1 peptide demonstrates an anti-inflammatory activity in the complete Freund's adjuvant (CFA)-induced autoimmune arthritis model in laboratory mice. It appears that the 17.1 peptide could potentially be used as an anti-inflammatory agent.

Asunto(s)

Antiinflamatorios/metabolismo , Antiinflamatorios/farmacología , Apoptosis/efectos de los fármacos , Citocinas/química , Proteínas HSP70 de Choque Térmico/metabolismo , Péptidos/metabolismo , Péptidos/farmacología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Animales , Antiinflamatorios/uso terapéutico , Artritis Reumatoide/inducido químicamente , Artritis Reumatoide/tratamiento farmacológico , Citocinas/inmunología , Modelos Animales de Enfermedad , Femenino , Fibroblastos/metabolismo , Adyuvante de Freund/efectos adversos , Células HEK293 , Humanos , Inmunidad Innata , Ratones , Ratones Endogámicos ICR , Necroptosis/efectos de los fármacos , Péptidos/uso terapéutico , Unión Proteica , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/inmunología , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

PGLYRP1/Tag-7/PGRP-S is one of mammalian peptidoglycan recognition proteins (PGRPs). Here, we demonstrate that human recombinant PGLYRP1/Tag-7/PGRP-S potentiates the response of murine macrophage-like ANA-1 cells and human macrophages to facultative intracellular pathogen Listeria monocytogenes. PGLYRP1/Tag-7/PGRP-S binds to the surface of L. monocytogenes and other bacterial cells but has no effect on their growth in culture. While PGLYRP1/Tag-7/PGRP-S treatment modestly enhanced phagocytosis of bacteria by ANA-1 cells, the intracellular survival of PGLYRP1/Tag-7/PGRP-S treated L. monocytogenes was strongly inhibited 2 h after internalization. PGLYRP1/Tag-7/PGRP-S treatment of bacteria boosted oxidative burst induction and increased the level of proinflammatory cytokine IL-6 produced by ANA-1, however, these effects happened too late to be responsible for decreased intracellular survival of bacteria. Our results thus suggest that PGLYRP1/Tag-7/PGRP-S acts as a molecular sensor for detection of L. monocytogenes infection of mammalian cells that leads to increased killing through a mechanism(s) that remains to be defined.

Asunto(s)

Citocinas , Espacio Intracelular , Listeria monocytogenes , Listeriosis , Macrófagos , Viabilidad Microbiana , Animales , Línea Celular , Citocinas/genética , Citocinas/inmunología , Citocinas/metabolismo , Humanos , Espacio Intracelular/microbiología , Listeria monocytogenes/metabolismo , Listeriosis/inmunología , Listeriosis/microbiología , Macrófagos/inmunología , Macrófagos/microbiología , Ratones , Fagocitosis , Estallido Respiratorio

RESUMEN

Tilorone hydrochloride, a low-molecular-weight synthetic compound, induces interferon production and has been reported to have both antiviral and antitumor activities. Here, we have demonstrated the ability of tilorone to activate NK cells and specific subpopulations of cytotoxic CD4+ and CD8+ T lymphocytes that recognize immune-evasive tumor cells and kill them via the FasL-Fas interaction. We have also performed a comparative analysis of characteristics between lymphocytes activated in the fraction of human peripheral blood mononuclear cells (PBMCs) upon treatment with different stimulants of the immune response: tilorone, innate immunity protein Tag7, and cytokine IL-2, a regulator of adaptive immunity. The results show that all the three stimulants, regardless of their nature, activate lymphocytes that are identical with respect to the spectrum of target cells, phenotype, and mechanism of cytotoxic action However, these stimulants induce different mechanisms of lymphocyte activation at early stages of the immune response. © 2018 IUBMB Life, 71(3):376-384, 2019.

Asunto(s)

Antineoplásicos/farmacología , Regulación Leucémica de la Expresión Génica , Células Asesinas Naturales/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Linfocitos T Citotóxicos/efectos de los fármacos , Tilorona/farmacología , Animales , Línea Celular , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Citocinas/farmacología , Citotoxicidad Inmunológica/efectos de los fármacos , Proteína Ligando Fas/genética , Proteína Ligando Fas/inmunología , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/inmunología , Células HeLa , Humanos , Inmunidad Innata/efectos de los fármacos , Interleucina-2/farmacología , Células K562 , Células Asesinas Naturales/citología , Células Asesinas Naturales/inmunología , Ratones , Cultivo Primario de Células , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/inmunología , Receptor fas/genética , Receptor fas/inmunología

RESUMEN

Recently we have found that cytokine IL-2 and innate immunity protein Tag7 activate cytotoxic lymphocytes that kill HLA-negative tumor cells, inducing both apoptosis and necroptosis. Here we decrypt the processes, taking part in necroptosis execution after FasL-Fas interaction. Necroptosis begins with RIPK1 activation and necrosome formation. Subsequent activation of MLKL results in the increase of Ca2+ level in the cell and activation of Ca2+-dependent enzymes causing lysosomal membrane permeabilization and the release of cathepsins to the cytosol. STAT3 translocation to the mitochondria and binding to a component of the respiratory chain complex I causes ROS accumulation. We have shown that transduction of necroptotic signal via TNFR1 and Fas has many common points. It is known that apoptosis plays a major role in physiological cell death; however, under pathological conditions necroptosis is very common. That is why the detailed mechanisms of FasL-Fas necroptosis can help in understanding the processes of elimination of tumor cells that have blocked apoptosis signal transduction.

Asunto(s)

Apoptosis , Citocinas/metabolismo , Proteína Ligando Fas/metabolismo , Antígenos HLA/metabolismo , Activación de Linfocitos , Lisosomas/metabolismo , Mitocondrias/metabolismo , Calpaína/metabolismo , Activación Enzimática , Humanos , Células K562 , Necrosis , Fosfolipasas A2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal

RESUMEN

The discovery of new chemokines that induce the migration of lymphocytes to the infection site is important for the targeted search for therapeutic agents in immunotherapy. We recently showed that Tag7 (PGLYRP1), an innate immunity protein, forms a stable complex with the Ca2+ -binding protein Mts1 (S100A4), which is able to induce lymphocyte movement, although the individual Tag7 and Mts1 do not have this activity. The purpose of this study is to identify receptors that induce the migration of lymphocytes along the concentration gradient of the Tag7-Mts1 complex, and the components of this complex capable of interacting with these receptors. The study investigated the migration of human PBMC under the action of the Tag7-Mts1complex. PBMC of healthy donors were isolated using a standard Ficoll-Hypaque gradient centrifugation procedure. It has been established that the movement of PBMC along the concentration gradient of the Tag7-Mts1 complex is induced by the classical chemotactic receptors CCR5 and CXCR3. It has been shown that only Mts1 is able to bind to the extracellular domain of CCR5, however, this binding is not enough to induce cell movement. A comparative analysis of the primary and 3D structures of the three proteins revealed the homology of the amino acid sequence fragments of the Tag7-Mts1 protein complex with different sites of the CCR5 receptor ligand - MIP1α protein. In conclusion, it should be noted that the Tag7-Mts1 complex can be considered as a new ligand of the classical chemotactic receptors CCR5 and CXCR3.

RESUMEN

The search for new immune response mechanisms capable of controlling immune-evasive tumor cells devoid of the MHC antigen is a challenging task for immunologists. In this study, we found that the treatment of human peripheral blood lymphocytes with the innate immunity protein Tag7 (PGRP-S, PGLYRP1) induces differentiation of the populations of NK (natural killer) cells and CD8+ and CD4+ T lymphocytes that are cytotoxic for human leukocyte antigen-negative tumor cells. These populations employ different mechanisms of tumor cell lysis (based on the release of granzymes in the case of NK cells and on the FasL-Fas interaction in the case of CD8+ and CD4+ T lymphocytes) and induce different death pathways (apoptosis or necroptosis) in tumor cells. An analysis of genes activated in leukocyte populations after Tag7 treatment and experiments with specific inhibitors have shown that the TREM-1 receptor expressed on the monocyte cell surface is essential for activation of cytotoxic activity. Overall, the results of this study provide evidence for a novel role of the Tag7 protein in the immune response.

Asunto(s)

Citocinas/metabolismo , Células Asesinas Naturales/inmunología , Leucemia Mielógena Crónica BCR-ABL Positiva/inmunología , Monocitos/metabolismo , Subgrupos de Linfocitos T/inmunología , Linfocitos T Citotóxicos/inmunología , Receptor Activador Expresado en Células Mieloides 1/metabolismo , Muerte Celular , Citotoxicidad Inmunológica , Proteína Ligando Fas/metabolismo , Granzimas/metabolismo , Antígenos HLA/metabolismo , Humanos , Células K562 , Receptor fas/metabolismo

RESUMEN

The innate immunity protein Tag7 (PGRP-S, PGLYRP1) is involved in antimicrobial and antitumor defense. As shown in our previous studies, Tag7 specifically interacts with the major heat shock protein Hsp70 to form a stable Tag7-Hsp70 complex with cytotoxic activity against tumor cells. A stable complex of Tag7 with the calcium-binding protein Mts1 (S100A4) stimulates migration of lymphocytes. Moreover, Tag7 can activate cytotoxic lymphocytes that recognize and kill HLA-negative tumor cells. Here, we have shown that Tag 7 treatment of human peripheral blood mononuclear cells (PBMCs) results in activation of different cytotoxic lymphocyte populations-natural killer (NK) cells and CD8+ NKG2D+ T lymphocytes-that kill Moloney murine leukemia virus (MMLV) infected SC-1 cells using different mechanisms of cell death induction. This mechanism in NK cells is based on the release of granzymes, which activate apoptosis in target cells, while CD8+ NKG2D+ T lymphocytes recognize the noncanonical MicA antigen on the surface of virus-containing cells and kill them via the FasL-Fas interaction, triggering the apoptotic or necroptotic cell death pathway. Preliminary incubation of PBMCs with virus-infected cells and following incubation with Tag7 results in activation of lymphocytes with a different phenotype. These lymphocytes change the spectrum of target cells and the mechanism of cell death induction, and their interaction with target cells is not species-specific. © 2017 IUBMB Life, 69(12):971-977, 2017.

Asunto(s)

Citocinas/inmunología , Citotoxicidad Inmunológica/efectos de los fármacos , Proteína Ligando Fas/inmunología , Células Asesinas Naturales/inmunología , Linfocitos T Citotóxicos/inmunología , Receptor fas/inmunología , Animales , Apoptosis/genética , Apoptosis/inmunología , Línea Celular , Técnicas de Cocultivo , Citocinas/genética , Citocinas/farmacología , Proteína Ligando Fas/genética , Fibroblastos/inmunología , Fibroblastos/virología , Expresión Génica , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Inmunidad Innata , Células Asesinas Naturales/citología , Células Asesinas Naturales/efectos de los fármacos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/inmunología , Activación de Linfocitos/efectos de los fármacos , Ratones , Virus de la Leucemia Murina de Moloney/crecimiento & desarrollo , Virus de la Leucemia Murina de Moloney/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Necrosis/genética , Necrosis/inmunología , Cultivo Primario de Células , Unión Proteica , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/efectos de los fármacos , Receptor fas/genética

RESUMEN

Tag7 (PGRP-S or PGLYRP1), while possessing an antimicrobial activity, also exhibits an antitumor effect when in complex with the major heat shock protein Hsp70. The cytotoxic Tag7-Hsp70 complex is secreted by lymphocytes after interaction with the HLA-negative tumors. Previously, we have shown that IL-2 induces formation of the CD4+ and CD8+ cytotoxic subpopulations of human lymphocytes, which kill tumor cells through the FasL-Fas interaction. Here, we show that only the CD8+ T cells are able to secrete the Tag7-Hsp70 complex. For its secretion the same proteins on the surface of the lymphocytes and target cells, which are involved in the contact lysis, are necessary as well. The interaction of Fas receptor with FasL leads to an activation of the Tag7-Hsp70 complex in the lymphocyte membrane fraction, and here FasL acts as a receptor that induces intracellular signaling in lymphocytes. An interaction of the MicA stress ligand with the NKG2D receptor is necessary for the release of this cytotoxic complex. It is possible, that CD8+ T lymphocytes interacting with a target cell can both carry out the contact killing of these cells and to secrete the cytotoxic factor. © 2016 IUBMB Life, 69(1):30-36, 2017.

Asunto(s)

Linfocitos T CD8-positivos/inmunología , Citocinas/genética , Proteína Ligando Fas/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Citotoxicidad Inmunológica , Proteína Ligando Fas/inmunología , Fibroblastos/inmunología , Fibroblastos/metabolismo , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Interleucina-2/inmunología , Interleucina-2/metabolismo , Células K562 , Ratones , Complejos Multiproteicos/genética , Complejos Multiproteicos/inmunología , Complejos Multiproteicos/metabolismo , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología

RESUMEN

Tag7 (PGRP-S, or PGLYRP1), an innate immunity protein, plays an important role in the immune defense system. It forms a stable cytotoxic complex with the heat shock protein Hsp70. This complex can induce an apoptotic or necroptotic tumor cell death by interacting with the TNFR1 receptor. In this study, we analyzed molecular events involved in the process of the Tag7-Hsp70-induced necroptosis. We found that Tag7 can bind to sTNFR1, a soluble fragment of the TNFR1 receptor, leading to an inhibition of the RIP1 dependent necroptosis. A major role in the downstream phases of the Tag7-Hsp70 induced necroptosis was played by an interaction between lysosomes and mitochondria. The interaction of Tag7-Hsp70 with the TNFR1 receptor triggered a certain sequence of events: at first, it activated RIP1 kinase, and later on, increased intracellular concentration of Са(2+) ions and an activation of calpains, which led to the permeabilization of the lysosomal membranes. The consequent release of the lysosomal enzymes, including cathepsins B and D, resulted in the depolarization of the mitochondrial membrane, ROS production, and eventual cell death.

Asunto(s)

Apoptosis , Permeabilidad de la Membrana Celular , Citocinas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Lisosomas/metabolismo , Mitocondrias/metabolismo , Animales , Ratones

RESUMEN

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7-Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4(+) and CD8(+) lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.

Asunto(s)

Quimiotaxis de Leucocito/inmunología , Inhibidor p16 de la Quinasa Dependiente de Ciclina/inmunología , Citocinas/inmunología , Inmunidad Innata , Células Asesinas Naturales/inmunología , Inmunidad Adaptativa , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Separación Celular , Quimiotaxis de Leucocito/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/farmacología , Citocinas/genética , Citocinas/farmacología , Escherichia coli , Regulación de la Expresión Génica , Humanos , Células Asesinas Naturales/citología , Células Asesinas Naturales/efectos de los fármacos , Monocitos/citología , Monocitos/efectos de los fármacos , Monocitos/inmunología , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Neutrófilos/inmunología , Cultivo Primario de Células , Unión Proteica , Proteínas Recombinantes , Transducción de Señal

RESUMEN

Tag7 (also known as peptidoglycan recognition protein PGRP-S, PGLYRP1), an innate immunity protein, interacts with Hsp70 to form a stable Tag7-Hsp70 complex with cytotoxic activity against some tumor cell lines. In this study, we have analyzed the programmed cell death mechanisms that are induced when cells interact with the Tag7-Hsp70 complex, which was previously shown to be released by human lymphocytes and is cytotoxic to cancer cells. We show that this complex induces both apoptotic and necroptotic processes in the cells. Apoptosis follows the classic caspase-8 and caspase-3 activation pathway. Inhibition of apoptosis leads to a switch to the RIP1-dependent necroptosis. Both of these cytotoxic processes are initiated by the involvement of TNFR1, a receptor for TNF-α. Our results suggest that the Tag7-Hsp70 complex is a novel ligand for this receptor. One of its components, the innate immunity protein Tag7, can bind to the TNFR1 receptor, thereby inhibiting the cytotoxic actions of the Tag7-Hsp70 complex and TNF-α, an acquired immunity cytokine.

Asunto(s)

Apoptosis , Citocinas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Animales , Caspasas/metabolismo , Línea Celular , Células Clonales , Células HEK293 , Humanos , Ratones , Necrosis , Unión Proteica , Factor de Necrosis Tumoral alfa/metabolismo