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X inactivation (XCI) is triggered by upregulation of XIST, which coats the chromosome in cis, promoting formation of a heterochromatic domain (Xi). XIST role beyond initiation of XCI is only beginning to be elucidated. Here, we demonstrate that XIST loss impairs differentiation of human mammary stem cells (MaSCs) and promotes emergence of highly tumorigenic and metastatic carcinomas. On the Xi, XIST deficiency triggers epigenetic changes and reactivation of genes overlapping Polycomb domains, including Mediator subunit MED14. MED14 overdosage results in increased Mediator levels and hyperactivation of the MaSC enhancer landscape and transcriptional program, making differentiation less favorable. We further demonstrate that loss of XIST and Xi transcriptional instability is common among human breast tumors of poor prognosis. We conclude that XIST is a gatekeeper of human mammary epithelium homeostasis, thus unveiling a paradigm in the control of somatic cell identity with potential consequences for our understanding of gender-specific malignancies.
Asunto(s)
Complejo Mediador/metabolismo , Células Madre Neoplásicas/metabolismo , ARN Largo no Codificante/metabolismo , Neoplasias de la Mama/metabolismo , Diferenciación Celular , Epigénesis Genética , Humanos , ARN Largo no Codificante/genética , Inactivación del Cromosoma XRESUMEN
Tumours progress despite being infiltrated by tumour-specific effector T cells. Tumours contain areas of cellular necrosis, which are associated with poor survival in a variety of cancers. Here, we show that necrosis releases intracellular potassium ions into the extracellular fluid of mouse and human tumours, causing profound suppression of T cell effector function. Elevation of the extracellular potassium concentration ([K+]e) impairs T cell receptor (TCR)-driven Akt-mTOR phosphorylation and effector programmes. Potassium-mediated suppression of Akt-mTOR signalling and T cell function is dependent upon the activity of the serine/threonine phosphatase PP2A. Although the suppressive effect mediated by elevated [K+]e is independent of changes in plasma membrane potential (Vm), it requires an increase in intracellular potassium ([K+]i). Accordingly, augmenting potassium efflux in tumour-specific T cells by overexpressing the potassium channel Kv1.3 lowers [K+]i and improves effector functions in vitro and in vivo and enhances tumour clearance and survival in melanoma-bearing mice. These results uncover an ionic checkpoint that blocks T cell function in tumours and identify potential new strategies for cancer immunotherapy.
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Cationes Monovalentes/metabolismo , Melanoma/inmunología , Potasio/metabolismo , Linfocitos T/inmunología , Escape del Tumor/inmunología , Microambiente Tumoral/inmunología , Animales , Humanos , Tolerancia Inmunológica/inmunología , Inmunoterapia/métodos , Canal de Potasio Kv1.3/metabolismo , Masculino , Melanoma/metabolismo , Melanoma/patología , Melanoma/terapia , Potenciales de la Membrana , Ratones , Necrosis , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Análisis de Supervivencia , Linfocitos T/metabolismo , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Bone marrow (BM) produces all blood and immune cells deriving from hematopoietic stem cells (HSCs). The decrease of immune cell production during aging is one of the features of immunosenescence. The impact of redox dysregulation in BM aging is still poorly understood. Here we use TP53INP1-deficient (KO) mice endowed with chronic oxidative stress to assess the influence of aging-associated redox alterations in BM homeostasis. We show that TP53INP1 deletion has no impact on aging-related accumulation of HSCs. In contrast, the aging-related contraction of the lymphoid compartment is mitigated in TP53INP1 KO mice. B cells that accumulate in old KO BM are differentiating cells that can mature into functional B cells. Importantly, this phenotype results from B cell-intrinsic events associated with defective redox control. Finally, we show that oxidative stress in aged TP53INP1-deficient mice maintains STAT5 expression and activation in early B cells, driving high Pax5 expression, which provides a molecular mechanism for maintenance of B cell development upon aging.
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Linfocitos B/fisiología , Médula Ósea/fisiología , Linfopoyesis , Proteínas Nucleares/deficiencia , Receptores de Interleucina-7/metabolismo , Factor de Transcripción STAT5/metabolismo , Transducción de Señal , Envejecimiento/fisiología , Animales , Linfocitos B/metabolismo , Médula Ósea/metabolismo , Linfopoyesis/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Oxidación-Reducción , Estrés OxidativoRESUMEN
Recent insight into the mechanisms of induction of tissue-resident memory (TRM) CD8+ T cells (CD8+ TRM) enables the development of novel vaccine strategies against sexually transmitted infections. To maximize both systemic and genital intraepithelial CD8+ T cells against vaccine Ags, we assessed combinations of i.m. and intravaginal routes in heterologous prime-boost immunization regimens with unrelated viral vectors. Only i.m. prime followed by intravaginal boost induced concomitant strong systemic and intraepithelial genital-resident CD8+ T cell responses. Intravaginal boost with vectors expressing vaccine Ags was far superior to intravaginal instillation of CXCR3 chemokine receptor ligands or TLR 3, 7, and 9 agonists to recruit and increase the pool of cervicovaginal CD8+ TRM Transient Ag presentation increased trafficking of cognate and bystander circulating activated, but not naive, CD8+ T cells into the genital tract and induced in situ proliferation and differentiation of cognate CD8+ TRM Secondary genital CD8+ TRM were induced in the absence of CD4+ T cell help and shared a similar TCR repertoire with systemic CD8+ T cells. This prime-pull-amplify approach elicited systemic and genital CD8+ T cell responses against high-risk human papillomavirus type 16 E7 oncoprotein and conferred CD8-mediated protection to a vaccinia virus genital challenge. These results underscore the importance of the delivery route of nonreplicating vectors in prime-boost immunization to shape the tissue distribution of CD8+ T cell responses. In this context, the importance of local Ag presentation to elicit genital CD8+ TRM provides a rationale to develop novel vaccines against sexually transmitted infections and to treat human papillomavirus neoplasia.
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Linfocitos T CD8-positivos/inmunología , Papillomavirus Humano 16/inmunología , Vacunas contra Papillomavirus/inmunología , Animales , Células HEK293 , Humanos , Ratones , Ratones Congénicos , Ratones Endogámicos C57BL , Vacunas contra Papillomavirus/genética , VacunaciónRESUMEN
Sos-1 and Sos-2 are ubiquitously expressed Ras-guanine exchange factors involved in Erk-MAP kinase pathway activation. Using mice lacking genes encoding Sos-1 and Sos-2, we evaluated the role of these proteins in peripheral T-cell signaling and function. Our results confirmed that TCR-mediated Erk activation in peripheral CD4(+) T cells does not depend on Sos-1 and Sos-2, although IL-2-mediated Erk activation does. Unexpectedly, however, we show an increase in AKT phosphorylation in Sos-1/2dKO CD4(+) T cells upon TCR and IL-2 stimulation. Activation of AKT was likely a consequence of increased recruitment of PI3K to Grb2 upon TCR and/or IL-2 stimulation in Sos-1/2dKO CD4(+) T cells. The increased activity of the PI3K/AKT pathway led to downregulation of the surface receptor CD62L in Sos-1/2dKO T cells and a subsequent impairment in T-cell migration.
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Linfocitos T CD4-Positivos/inmunología , Movimiento Celular/inmunología , Fosfatidilinositol 3-Quinasas/inmunología , Proteína SOS1/inmunología , Transducción de Señal/inmunología , Proteínas Son Of Sevenless/inmunología , Animales , Movimiento Celular/genética , Activación Enzimática/genética , Activación Enzimática/inmunología , Proteína Adaptadora GRB2/genética , Proteína Adaptadora GRB2/inmunología , Interleucina-2/genética , Interleucina-2/inmunología , Selectina L/genética , Selectina L/inmunología , Ratones , Ratones Noqueados , Fosfatidilinositol 3-Quinasas/genética , Fosforilación/genética , Fosforilación/inmunología , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/inmunología , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Proteína SOS1/genética , Transducción de Señal/genética , Proteínas Son Of Sevenless/genéticaRESUMEN
Programmed death receptor 1 (PD-1) is an important signaling molecule often involved in tumor-mediated suppression of activated immune cells. Binding of this receptor to its ligands, B7-H1 (PD-L1) and B7-DC (PD-L2), attenuates T cell activation, reduces IL-2 and IFN-γ secretion, decreases proliferation and cytotoxicity, and induces apoptosis. B7-DC-Ig is a recombinant protein that binds and targets PD-1. It is composed of an extracellular domain of murine B7-DC fused to the Fc portion of murine IgG2a. In this study, we demonstrate that B7-DC-Ig can enhance the therapeutic efficacy of vaccine when combined with cyclophosphamide. We show that this combination significantly enhances Ag-specific immune responses and leads to complete eradication of established tumors in 60% of mice and that this effect is CD8 dependent. We identified a novel mechanism by which B7-DC-Ig exerts its therapeutic effect that is distinctly different from direct blocking of the PD-L1-PD-1 interaction. In this study, we demonstrate that there are significant differences between levels and timing of surface PD-1 expression on different T cell subsets. We found that these differences play critical roles in anti-tumor immune effect exhibited by B7-DC-Ig through inhibiting proliferation of PD-1(high) CD4 T cells, leading to a significant decrease in the level of these cells, which are enriched for regulatory T cells, within the tumor. In addition, it also leads to a decrease in PD-1(high) CD8 T cells, tipping the balance toward nonexhausted functional PD-1(low) CD8 T cells. We believe that the PD-1 expression level on T cells is a crucial factor that needs to be considered when designing PD-1-targeting immune therapies.
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Vacunas contra el Cáncer/inmunología , Receptor de Muerte Celular Programada 1/fisiología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Escape del Tumor/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Adyuvantes Inmunológicos/genética , Animales , Antígeno B7-H1 , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Vacunas contra el Cáncer/administración & dosificación , Vacunas contra el Cáncer/genética , Sistemas de Liberación de Medicamentos/métodos , Femenino , Ratones , Ratones Endogámicos C57BL , Receptor de Muerte Celular Programada 1/biosíntesis , Receptor de Muerte Celular Programada 1/genética , Receptor de Muerte Celular Programada 1/metabolismo , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunologíaRESUMEN
Targeting intracellular inhibiting proteins has been revealed to be a promising strategy to improve CD8+ T cell anti-tumor efficacy. Here, we are focusing on intracellular inhibiting proteins specific to TCR signaling: DOK1 and DOK2 expressed in T cells. We hypothesized that depletion of intracellular inhibition checkpoint DOK1 and DOK2 could improve CD8+ T-cell based cancer therapies. To evaluate the role of DOK1 and DOK2 depletion in physiology and effector function of CD8+ T lymphocytes and in cancer progression, we established a transgenic T cell receptor mouse model specific to melanoma antigen hgp100 (pmel-1 TCR Tg) in WT and Dok1/Dok2 DKO (double KO) mice. We showed that both DOK1 and DOK2 depletion in CD8+ T cells after an in vitro pre-stimulation induced a higher percentage of effector memory T cells as well as an up regulation of TCR signaling cascade- induced by CD3 mAbs, including the increased levels of pAKT and pERK, two major phosphoproteins involved in T cell functions. Interestingly, this improved TCR signaling was not observed in naïve CD8+ T cells. Despite this enhanced TCR signaling essentially shown upon stimulation via CD3 mAbs, pre-stimulated Dok1/Dok2 DKO CD8+ T cells did not show any increase in their activation or cytotoxic capacities against melanoma cell line expressing hgp100 in vitro. Altogether we demonstrate here a novel aspect of the negative regulation by DOK1 and DOK2 proteins in CD8+ T cells. Indeed, our results allow us to conclude that DOK1 and DOK2 have an inhibitory role following long term T cell stimulations.
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Proteínas Adaptadoras Transductoras de Señales , Linfocitos T CD8-positivos , Proteínas de Unión al ADN , Memoria Inmunológica , Ratones Noqueados , Fosfoproteínas , Proteínas de Unión al ARN , Receptores de Antígenos de Linfocitos T , Transducción de Señal , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Ratones , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Línea Celular Tumoral , Ratones TransgénicosRESUMEN
mRNA applications have undergone unprecedented applications-from vaccination to cell therapy. Natural killer (NK) cells are recognized to have a significant potential in immunotherapy. NK-based cell therapy has drawn attention as allogenic graft with a minimal graft-versus-host risk leading to easier off-the-shelf production. NK cells can be engineered with either viral vectors or electroporation, involving high costs, risks, and toxicity, emphasizing the need for alternative way as mRNA technology. We successfully developed, screened, and optimized novel lipid-based platforms based on imidazole lipids. Formulations are produced by microfluidic mixing and exhibit a size of approximately 100 nm with a polydispersity index of less than 0.2. They are able to transfect NK-92 cells, KHYG-1 cells, and primary NK cells with high efficiency without cytotoxicity, while Lipofectamine Messenger Max and D-Lin-MC3 lipid nanoparticle-based formulations do not. Moreover, the translation of non-modified mRNA was higher and more stable in time compared with a modified one. Remarkably, the delivery of therapeutically relevant interleukin 2 mRNA resulted in extended viability together with preserved activation markers and cytotoxic ability of both NK cell lines and primary NK cells. Altogether, our platforms feature all prerequisites needed for the successful deployment of NK-based therapeutic strategies.
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Primary human mammary epithelial cells (pHMECs) are known to be remarkably difficult to engineer genetically. Here, we present a protocol for efficient transduction of pHMECs using a baboon retroviral envelope glycoprotein for pseudotyping of lentiviral vectors (BaEV-LVs). We describe the preparation of the BaEV-LVs, the isolation of pHMECs from breast samples, and the subsequent transduction of pHMECs. We also detail the use of CRISPRi technology to efficiently silence gene expression in pHMECs, which can then be used for functional assays. For complete details on the use and execution of this protocol, please refer to Richart et al. (2022).1.
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Vectores Genéticos , Lentivirus , Animales , Humanos , Lentivirus/metabolismo , Vectores Genéticos/genética , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo , Transducción Genética , Papio/genética , Papio/metabolismo , Células Epiteliales/metabolismoRESUMEN
Immunotherapy strategies aim to mobilize immune defenses against tumor cells by targeting mainly T cells. Co-inhibitory receptors or immune checkpoints (ICPs) (such as PD-1 and CTLA4) can limit T cell receptor (TCR) signal propagation in T cells. Antibody-based blocking of immune checkpoints (immune checkpoint inhibitors, ICIs) enable escape from ICP inhibition of TCR signaling. ICI therapies have significantly impacted the prognosis and survival of patients with cancer. However, many patients remain refractory to these treatments. Thus, alternative approaches for cancer immunotherapy are needed. In addition to membrane-associated inhibitory molecules, a growing number of intracellular molecules may also serve to downregulate signaling cascades triggered by TCR engagement. These molecules are known as intracellular immune checkpoints (iICPs). Blocking the expression or the activity of these intracellular negative signaling molecules is a novel field of action to boost T cell-mediated antitumor responses. This area is rapidly expanding. Indeed, more than 30 different potential iICPs have been identified. Over the past 5 years, several phase I/II clinical trials targeting iICPs in T cells have been registered. In this study, we summarize recent preclinical and clinical data demonstrating that immunotherapies targeting T cell iICPs can mediate regression of solid tumors including (membrane associated) immune-checkpoint inhibitor refractory cancers. Finally, we discuss how these iICPs are targeted and controlled. Thereby, iICP inhibition is a promising strategy opening new avenues for future cancer immunotherapy treatments.
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Inmunoterapia , Neoplasias , Humanos , Neoplasias/terapia , Neoplasias/metabolismo , Linfocitos TRESUMEN
BACKGROUND: Tumor necrosis factor superfamily member 14 (TNFRSF14)/herpes virus entry mediator (HVEM) is the ligand for B and T lymphocyte attenuator (BTLA) and CD160-negative immune co-signaling molecules as well as viral proteins. Its expression is dysregulated with an overexpression in tumors and a connection with tumors of adverse prognosis. METHODS: We developed C57BL/6 mouse models co-expressing human (hu)BTLA and huHVEM as well as antagonistic monoclonal antibodies (mAbs) that completely prevent the interactions of HVEM with its ligands. RESULTS: Here, we show that the anti-HVEM18-10 mAb increases primary human αß-T cells activity alone (CIS-activity) or in the presence of HVEM-expressing lung or colorectal cancer cells in vitro (TRANS-activity). Anti-HVEM18-10 synergizes with antiprogrammed death-ligand 1 (anti-PD-L1) mAb to activate T cells in the presence of PD-L1-positive tumors, but is sufficient to trigger T cell activation in the presence of PD-L1-negative cells. In order to better understand HVEM18-10 effects in vivo and especially disentangle its CIS and TRANS effects, we developed a knockin (KI) mouse model expressing human BTLA (huBTLA+/+) and a KI mouse model expressing both huBTLA+/+/huHVEM+/+ (double KI (DKI)). In vivo preclinical experiments performed in both mouse models showed that HVEM18-10 treatment was efficient to decrease human HVEM+ tumor growth. In the DKI model, anti-HVEM18-10 treatment induces a decrease of exhausted CD8+ T cells and regulatory T cells and an increase of effector memory CD4+ T cells within the tumor. Interestingly, mice which completely rejected tumors (±20%) did not develop tumors on rechallenge in both settings, therefore showing a marked T cell-memory phenotype effect. CONCLUSIONS: Altogether, our preclinical models validate anti-HVEM18-10 as a promising therapeutic antibody to use in clinics as a monotherapy or in combination with existing immunotherapies (antiprogrammed cell death protein 1/anti-PD-L1/anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4)).
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Linfocitos T CD8-positivos , Neoplasias , Miembro 14 de Receptores del Factor de Necrosis Tumoral , Animales , Humanos , Ratones , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Linfocitos T CD8-positivos/metabolismo , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptores Inmunológicos/metabolismo , Miembro 14 de Receptores del Factor de Necrosis Tumoral/inmunología , Miembro 14 de Receptores del Factor de Necrosis Tumoral/metabolismoRESUMEN
Strategies are being explored to increase the efficiency of immune checkpoint inhibitors (ICIs) targeting PD1/PDL1 in triple-negative breast cancer (TNBC), including combination with therapies inhibiting intracellular immune checkpoints such as CISH (Cytokine-induced SH2 protein). Correlation between CISH expression and TNBC features is unknown. We retrospectively analyzed CISH expression in 1936 clinical TNBC samples and searched for correlations with clinical variables, including metastasis-free interval (MFI). Among TNBCs, 44% were identified as "CISH-up" and 56% "CISH-down". High expression was associated with pathological axillary lymph node involvement, more adjuvant chemotherapy, and Lehmann's immunomodulatory and luminal AR subtypes. The "CISH-up" class showed longer 5-year MFI (72%) than the "CISH-down" class (60%; p = 2.8 × 10-2). CISH upregulation was associated with activation of IFNα and IFNγ pathways, antitumor cytotoxic immune response, and signatures predictive for ICI response. When CISH and PDL1 were upregulated together, the 5-year MFI was 81% versus 52% when not upregulated (p = 6.21 × 10-6). The two-gene model provided more prognostic information than each gene alone and maintained its prognostic value in multivariate analysis. CISH expression is associated with longer MFI in TNBC and refines the prognostic value of PDL1 expression. Such observation might reinforce the therapeutic relevance of combining CISH inhibition with an anti-PD1/PDL1 ICI.
RESUMEN
BACKGROUND: The success and limitations of current immunotherapies have pushed research toward the development of alternative approaches and the possibility to manipulate other cytotoxic immune cells such as natural killer (NK) cells. Here, we targeted an intracellular inhibiting protein 'cytokine inducible SH2-containing protein' (CISH) in NK cells to evaluate the impact on their functions and antitumor properties. METHODS: To further understand CISH functions in NK cells, we developed a conditional Cish-deficient mouse model in NK cells (Cishfl/flNcr1Ki/+ ). NK cells cytokine expression, signaling and cytotoxicity has been evaluated in vitro. Using intravenous injection of B16F10 melanoma cell line and EO711 triple negative breast cancer cell line, metastasis evaluation was performed. Then, orthotopic implantation of breast tumors was performed and tumor growth was followed using bioluminescence. Infiltration and phenotype of NK cells in the tumor was evaluated. Finally, we targeted CISH in human NK-92 or primary NK cells, using a technology combining the CRISPR(i)-dCas9 tool with a new lentiviral pseudotype. We then tested human NK cells functions. RESULTS: In Cishfl/flNcr1Ki/+ mice, we detected no developmental or homeostatic difference in NK cells. Global gene expression of Cishfl/flNcr1Ki/+ NK cells compared with Cish+/+Ncr1Ki/+ NK cells revealed upregulation of pathways and genes associated with NK cell cycling and activation. We show that CISH does not only regulate interleukin-15 (IL-15) signaling pathways but also natural cytotoxicity receptors (NCR) pathways, triggering CISH protein expression. Primed Cishfl/flNcr1Ki/+ NK cells display increased activation upon NCR stimulation. Cishfl/flNcr1Ki/+ NK cells display lower activation thresholds and Cishfl/flNcr1Ki/+ mice are more resistant to tumor metastasis and to primary breast cancer growth. CISH deletion favors NK cell accumulation to the primary tumor, optimizes NK cell killing properties and decreases TIGIT immune checkpoint receptor expression, limiting NK cell exhaustion. Finally, using CRISPRi, we then targeted CISH in human NK-92 or primary NK cells. In human NK cells, CISH deletion also favors NCR signaling and antitumor functions. CONCLUSION: This study represents a crucial step in the mechanistic understanding and safety of Cish targeting to unleash NK cell antitumor function in solid tumors. Our results validate CISH as an emerging therapeutic target to enhance NK cell immunotherapy.
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Receptor 1 Gatillante de la Citotoxidad Natural , Neoplasias , Animales , Humanos , Células Asesinas Naturales , Ratones , Receptor 1 Gatillante de la Citotoxidad Natural/genética , Receptor 1 Gatillante de la Citotoxidad Natural/metabolismo , Proteínas Supresoras de la Señalización de Citocinas/metabolismoRESUMEN
Mutation of the TET2 DNA-hydroxymethylase has been associated with a number of immune pathologies. The disparity in phenotype and clinical presentation among these pathologies leads to questions regarding the role of TET2 mutation in promoting disease evolution in different immune cell types. Here we show that, in primary mast cells, Tet2 expression is induced in response to chronic and acute activation signals. In TET2-deficient mast cells, chronic activation via the oncogenic KITD816V allele associated with mastocytosis, selects for a specific epigenetic signature characterized by hypermethylated DNA regions (HMR) at immune response genes. H3K27ac and transcription factor binding is consistent with priming or more open chromatin at both HMR and non-HMR in proximity to immune genes in these cells, and this signature coincides with increased pathological inflammation signals. HMR are also associated with a subset of immune genes that are direct targets of TET2 and repressed in TET2-deficient cells. Repression of these genes results in immune tolerance to acute stimulation that can be rescued with vitamin C treatment or reiterated with a Tet inhibitor. Overall, our data support a model where TET2 plays a direct role in preventing immune tolerance in chronically activated mast cells, supporting TET2 as a viable target to reprogram the innate immune response for innovative therapies.
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Proteínas de Unión al ADN , Dioxigenasas , Tolerancia Inmunológica , Mastocitos , Proteínas de Unión al ADN/metabolismo , Dioxigenasas/metabolismo , Mastocitos/inmunología , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismoRESUMEN
Downstream of tyrosine kinase (Dok) proteins Dok-1 and Dok-2 are involved in T cell homeostasis maintenance. Dok protein tyrosine phosphorylation plays a key role in establishing negative feedback loops of T cell signaling. These structurally related adapter molecules contain a pleckstrin homology (PH) domain generally acting as a lipid/protein-interacting module. We show that the presence of this PH domain is necessary for the tyrosine phosphorylation of Dok proteins and their negative functions in T cells. We find that Dok-1/Dok-2 PH domains bind in vitro to the rare phosphoinositide species, phosphatidylinositol 5-phosphate (PtdIns5P). Dok tyrosine phosphorylation correlates with PtdIns5P production in T cells upon TCR triggering. Furthermore, we demonstrate that PtdIns5P increase regulates Dok tyrosine phosphorylation in vivo. Together, our data identify a novel lipid mediator in T cell signaling and suggest that PH-PtdIns5P interactions regulate T cell responses.
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Proteínas Adaptadoras Transductoras de Señales/inmunología , Proteínas de Unión al ADN/inmunología , Activación de Linfocitos/inmunología , Fosfatos de Fosfatidilinositol/biosíntesis , Fosfoproteínas/inmunología , Proteínas de Unión al ARN/inmunología , Transducción de Señal/inmunología , Linfocitos T/inmunología , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas de Unión al ADN/metabolismo , Células HeLa , Humanos , Células Jurkat , Fosfatos de Fosfatidilinositol/inmunología , Fosfoproteínas/metabolismo , Fosforilación , Proteínas de Unión al ARN/metabolismo , Resonancia por Plasmón de Superficie , Linfocitos T/metabolismoRESUMEN
Dok-4 (downstream of tyrosine kinase-4) is a recently identified member of the Dok family of adaptor proteins, which are characterized by an amino-terminal pleckstrin homology domain, a phosphotyrosine-binding domain, and a carboxyl-terminal region containing several tyrosines and poly-proline-rich motifs. Two members of the Dok family, Dok-1 and Dok-2, have already been described as negative regulators in T cells. However, the function of Dok-4, which is also expressed in T cells, remains unknown. In this study, we report that Dok-4 is phosphorylated after TCR engagement and shuttled within the cytoplasm of T cells before being recruited to the polarized microtubule organizing center after the formation of the immunological synapse. Loss-of-function experiments using RNA interference constructs show that Dok-4 is a negative regulator of ERK phosphorylation, IL-2 promoter activity, and T cell proliferation. Exogenous expression of wild-type Dok-4 induces a significant activation of Rap1, which is involved in the regulation of ERK. The pleckstrin homology domain of Dok-4 is required both for its cytoplasmic shuttling and relocalization as well as for its inhibitory properties on T cell activation. Thus, Dok-4 represents a novel negative regulator of T cells.
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Péptidos y Proteínas de Señalización Intracelular/metabolismo , Activación de Linfocitos/inmunología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Secuencias de Aminoácidos , Células Presentadoras de Antígenos/inmunología , Células Presentadoras de Antígenos/metabolismo , Comunicación Celular/inmunología , Línea Celular , Regulación de la Expresión Génica , Humanos , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/genética , Centro Organizador de los Microtúbulos/inmunología , Centro Organizador de los Microtúbulos/metabolismo , Fosfotirosina/metabolismo , Regiones Promotoras Genéticas/genética , Receptores de Antígenos de Linfocitos T/inmunología , Transducción de Señal/inmunologíaRESUMEN
Natural killer (NK) cell activation is controlled by a balance of activating and inhibitory signals and cytokines such as IL-15. We previously identified cytokine-inducible SH2-containing protein (CIS) as a negative regulator of IL-15 signaling in NK cells under inflammatory conditions. While the functional effect of Cish-deficiency in NK cells was obvious by their increased anti-tumor immunity and hyper-proliferative response to IL-15, it remained unclear how CIS regulates NK cell biology in steady-state. Here, we investigated the role of CIS in the homeostatic maintenance of NK cells and found CIS-ablation promoted terminal differentiation of NK cells and increased turnover, suggesting that under steady-state conditions, CIS plays a role in maintaining IL-15 driven regulation of NK cells in vivo. However, hyper-responsiveness to IL-15 did not manifest in NK cell accumulation, even when the essential NK cell apoptosis mediator, Bcl2l11 (BIM) was deleted in addition to Cish. Instead, loss of CIS conferred a lower activation threshold, evidenced by augmented functionality on a per cell basis both in vitro and in vivo without prior priming. We conclude that Cish regulates IL-15 signaling in NK cells in vivo, and through the rewiring of several activation pathways leads to a reduction in activation threshold, decreasing the requirement for priming and improving NK cell anti-tumor function. Furthermore, this study highlights the tight regulation of NK cell homeostasis by several pathways which prevent NK cell accumulation when IL-15 signaling and intrinsic apoptosis are dysregulated.
Asunto(s)
Diferenciación Celular/inmunología , Homeostasis/inmunología , Interleucina-15/inmunología , Células Asesinas Naturales/inmunología , Activación de Linfocitos/inmunología , Proteínas Supresoras de la Señalización de Citocinas/inmunología , Animales , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Women with low levels of vitamin D have a higher risk of developing breast cancer. Numerous studies associated the presence of a CD8+ T cell infiltration with a good prognosis. As vitamin D may play a key role in the modulation of the immune system, the objective of this work was to evaluate the impact of vitamin D on the breast cancer progression and mammary tumor microenvironment. We show that vitamin D decreases breast cancer tumor growth. Immunomonitoring of the different immune subsets in dissociated tumors revealed an increase in tumor infiltrating CD8+ T cells in the vitamin D-treated group. Interestingly, these CD8+ T cells exhibited a more active T cell (TEM/CM) phenotype. However, in high-fat diet conditions, we observed an opposite effect of vitamin D on breast cancer tumor growth, associated with a reduction of CD8+ T cell infiltration. Our data show that vitamin D is able to modulate breast cancer tumor growth and inflammation in the tumor microenvironment in vivo. Unexpectedly, this effect is reversed in high-fat diet conditions, revealing the importance of diet on tumor growth. We believe that supplementation with vitamin D can in certain conditions represent a new adjuvant in the treatment of breast cancers.
Asunto(s)
Neoplasias de la Mama/inmunología , Linfocitos T CD8-positivos/inmunología , Vitamina D/inmunología , Animales , Neoplasias de la Mama/patología , Linfocitos T CD8-positivos/patología , Línea Celular Tumoral , Proliferación Celular/fisiología , Progresión de la Enfermedad , Femenino , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/patología , Ratones , Ratones Endogámicos C57BL , Pronóstico , Microambiente Tumoral/inmunologíaRESUMEN
Downstream of Kinase (DOK) proteins represent a multigenic family of adaptors that includes negative regulators of immune cell signaling. Using phylogenetics and intron/exon structure data, we show here that the seven human DOK genes (DOK1 to DOK7) form three highly divergent groups that emerged before the protostome-deuterostome split: DOK1/2/3, DOK4/5/6, and DOK7. For two of these three groups (DOK1/2/3 and DOK4/5/6), further gene duplications occurred in vertebrates and so while chordates only have three DOK genes, vertebrates have seven DOK genes over the three groups. From our expression analysis in humans, we show that each group of DOK genes has a distinct pattern of expression. The DOK1/2/3 group is immune specific, yet each of the three genes in the group has a distinct pattern of expression in immune cells. This immune specificity could thus be ancestral, with the DOK1/2/3 gene also being immune-related in protostomes. The DOK4/5/6 and DOK7 groups represent genes that are much less expressed in immune system than the DOK1/2/3 group. Interestingly, we identify a novel tyrosine based motif that is specific to the vertebrate DOK4/5/6 sequences. The evolution of the DOK genes is thus marked by a pattern of ancient duplications and functional specializations.
Asunto(s)
Proteínas de Unión al ADN/genética , Sistema Inmunológico/fisiología , Proteínas Musculares/genética , Fosfoproteínas/genética , Proteínas de Unión al ARN/genética , Animales , Código de Barras del ADN Taxonómico , Evolución Molecular , Exones , Duplicación de Gen , Especiación Genética , Humanos , Inmunidad/genética , Familia de Multigenes/genética , Filogenia , Transducción de Señal , TranscriptomaRESUMEN
Cish, participates within a multi-molecular E3 ubiquitin ligase complex, which ubiquitinates target proteins. It has an inhibitory effect on T cell activation mediated by PLC-γ1 regulation, and it functions as a potent checkpoint in CD8+ T cell tumor immunotherapy. To study the structural and functional relationships between Cish and PLC-γ1 during CD8+ T cell activation, we tested mutants of the Cish-SH2 (R107K) and D/BC (L222Q, C226Q) domains. We confirmed that Cish-SH2-specific binding was essential for PLC-γ1 ubiquitination and degradation. This domain was essential for the Cish-mediated inhibition of Ca2+ release upon TCR stimulation. No effect on inhibition of cytokine release was observed with SH2 or D/BC mutants, although the absence of Cish led to an increased release of IFN-γ and TNF-α. Using imaging we showed that Cish was expressed mostly in the cytoplasm and we did not see any Cish clustering at the plasma membrane upon stimulation. We conclude that the Cish-SH2 domain is essential for PLC-γ1 regulation in TCR-stimulated CD8+ T cells.