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FCGR3A presents a single nucleotide polymorphism at location 158 (V/F), which affects its binding to the fragment crystallizable (Fc) of antibodies (Abs). FcγRIIIa-158 V allotype has the highest affinity and is associated with a better clinical response to IgG1 monoclonal Abs (mAb) treatment. We compared the allele frequency of FCGR3A-F158V polymorphism in cohorts of patients with B-cell lymphoproliferative disorders, including multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), non-Hodgkin lymphoma (NHL), and B-cell chronic leukemia (B-CLL). FCGR3A-158F homozygous were enriched and tended to be in MM and MGUS patients, respectively; but neither in B-CLL nor in NHL patients. We identified a significantly lower concentration of CD8 T-cells and resting memory CD4 T-cells in MM patients bone marrow with the F/F genotype, associated with an increase in the macrophage percentage. In contrast, natural killer cells increased in V/V homozygous patients. This suggests a deregulation of the immune microenvironment in FCGR3A-F/F homozygous patients. However, we did not observe difference in response following treatment combining chemotherapy associated or not with daratumumab, an IgG1 mAb direct against CD38. Our findings suggest that FCGR3A F158V polymorphism can regulate the immune environment and affect the development of tumor plasma cells.
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Frecuencia de los Genes , Mieloma Múltiple , Polimorfismo de Nucleótido Simple , Receptores de IgG , Humanos , Receptores de IgG/genética , Mieloma Múltiple/genética , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/inmunología , Masculino , Femenino , Persona de Mediana Edad , Anciano , Gammopatía Monoclonal de Relevancia Indeterminada/genética , Gammopatía Monoclonal de Relevancia Indeterminada/inmunología , GenotipoRESUMEN
Mucosal-associated invariant T (MAIT) cells are predominantly located in barrier tissues where they rapidly respond to pathogens and commensals by recognizing microbial derivatives of riboflavin synthesis. Early-life exposure to these metabolites imprints the abundance of MAIT cells within tissues, so we hypothesized that antibiotic use during this period may abrogate their development. We identified antibiotics that deplete riboflavin-synthesizing commensals and revealed an early period of susceptibility during which antibiotic administration impaired MAIT cell development. The reduction in MAIT cell abundance rendered mice more susceptible to pneumonia, while MAIT cell-deficient mice were unaffected by early-life antibiotics. Concomitant administration of a riboflavin-synthesizing commensal during antibiotic treatment was sufficient to restore MAIT cell development and immunity. Our work demonstrates that transient depletion of riboflavin-synthesizing commensals in early life can adversely affect responses to subsequent infections.
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FcRγ-deficient natural killer (NK) cells, designated as g-NK cells, exhibit enhanced antibody-dependent cellular cytotoxicity (ADCC) capacity and increased IFN-γ and TNF-α production, rendering them promising for antiviral and antitumor responses. g-NK cells from peripheral blood (PB) are often associated with prior human cytomegalovirus (HCMV) infection. However, the prevalence, phenotype, and function of g-NK cells in umbilical cord blood (UCB-g-NK) remain unclear. Here, we demonstrate significant phenotypical differences between UCB-g-NK and PB-g-NK cells. Unlike PB-g-NK cells, UCB-g-NK cells did not show heightened cytokine production upon CD16 engagement, in contrast to the conventional NK (c-NK) cell counterparts. Interestingly, following in vitro activation, UCB-g-NK cells also exhibited elevated levels of IFN-γ production, particularly when co-cultured with HCMV and plasma from g-NK+ adults. Furthermore, g-NK+ plasma from PB even facilitated the in vitro expansion of UCB-g-NK cells. These findings underscore the phenotypic and functional heterogeneity of g-NK cells based on their origin and demonstrate that components within g-NK+ plasma may directly contribute to the acquisition of an adult phenotype by the "immature" UCB-g-NK cells.
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Sangre Fetal , Activación de Linfocitos , Adulto , Humanos , Células Asesinas Naturales , Citotoxicidad Celular Dependiente de Anticuerpos , CitomegalovirusRESUMEN
The innate immune lymphocyte lineage natural killer (NK) cell infiltrates tumor environment where it can recognize and eliminate tumor cells. NK cell tumor infiltration is linked to patient prognosis. However, it is unknown if some of these antitumor NK cells leave the tumor environment. In blood-borne cancers, NK cells that have interacted with leukemic cells are recognized by the co-expression of two CD45 isoforms (CD45RARO cells) and/or the plasma membrane presence of tumor antigens (Ag), which NK cells acquire by trogocytosis. We evaluated solid tumor Ag uptake by trogocytosis on NK cells by performing co-cultures in vitro. We analyzed NK population subsets by unsupervised dimensional reduction techniques in blood samples from breast tumor (BC) patients and healthy donors (HD). We confirmed that NK cells perform trogocytosis from solid cancer cells in vitro. The extent of trogocytosis depends on the target cell and the antigen, but not on the amount of Ag expressed by the target cell or the sensitivity to NK cell killing. We identified by FlowSOM (Self-Organizing Maps) several NK cell clusters differentially abundant between BC patients and HD, including anti-tumor NK subsets with phenotype CD45RARO+CD107a+. These analyses showed that bona-fide NK cells that have degranulated were increased in patients and, additionally, these NK cells exhibit trogocytosis of solid tumor Ag on their surface. However, the frequency of NK cells that have trogocytosed is very low and much lower than that found in hematological cancer patients, suggesting that the number of NK cells that exit the tumor environment is scarce. To our knowledge, this is the first report describing the presence of solid tumor markers on circulating NK subsets from breast tumor patients. This NK cell immune profiling could lead to generate novel strategies to complement established therapies for BC patients or to the use of peripheral blood NK cells in the theranostic of solid cancer patients after treatment.
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Neoplasias de la Mama , Neoplasias Hematológicas , Neoplasias Mamarias Animales , Animales , Humanos , Femenino , Antígenos de Neoplasias , Células Asesinas Naturales , Membrana CelularRESUMEN
Senescent cells promote progressive tissue degeneration through the establishment of a combined inflammatory and trophic microenvironment. The cellular senescence state has therefore emerged as a central driving mechanism of numerous age-related diseases, including osteoarthritis (OA), the most common rheumatic disease. Senescence hallmarks are detectable in chondrocytes, synoviocytes and sub-chondral bone cells. This study investigates how the senescence-driven microenvironment could impact the cell fate of resident osteoarticular mesenchymal stromal/stem cells (MSCs) that are hence contributing to OA disease progression. For that purpose, we performed a comparative gene expression analysis of MSCs isolated from healthy donors that were in vitro chronically exposed either to interferon-gamma (IFN-γ) or Transforming Growth Factor beta 1 (TGFß1), two archetypical factors produced by senescent cells. Both treatments reduced MSC self-renewal capacities by upregulating different senescence-driven cycle-dependent kinase inhibitors. Furthermore, a common set of differentially expressed genes was identified in both treated MSCs that was also found enriched in MSCs isolated from OA patients. These findings highlight an imprinting of OA MSCs by the senescent joint microenvironment that changes their matrisome gene expression. Altogether, this research gives new insights into OA etiology and points to new innovative therapeutic opportunities to treat OA patients.
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CD20 monoclonal antibodies (mAbs) eliminate B cells in several clinical contexts. At least two of these Abs, obinutuzumab (OBI) and rituximab (RTX), induce quick elimination of targets and put cancer patients at risk of tumor lysis syndrome (TLS) within 12-24 h of the first dose. The mechanisms of killing can require the recruiting of effector mechanisms from the patient's immune system, but they can induce direct killing as well. This can be more rapid than recruiting cellular effectors and/or complement. We showed here that OBI and RTX induce quick (<1 h) and high (up to 60% for OBI) killing of two different B cell lines. This was unveiled by using two different techniques that circumvent cell centrifugation steps: a Muse® Cell Analyzer-based approach and a direct examination of the cells' physical properties by using forward scatter (FS) area and side scatter (SS) area by flow cytometry. These results excluded the presence of aggregates and were also confirmed by developing a normalized survival ratio based on the co-incubation of RTX- and OBI-sensitive cells with MOLM-13, an insensitive cell line. Finally, this normalized survival ratio protocol confirmed the RTX- and OBI-direct killing on primary tumor B cells from B cell chronic lymphocytic leukemia (B-CLL) and Non-Hodgkin's lymphoma (NHL) patients. Moreover, we unveiled that direct killing is higher than previously expected and absent in patients' samples at relapse. We also observed that these mAbs, prior to increasing intracellular calcium levels, decrease calcium entry, although manipulating calcium levels did not affect their cytotoxicity. Altogether, our results show that direct killing is a major mechanism to induce cell death by RTX and OBI mAbs.
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The pathogenicity of disease-associated microbes varies widely between individuals. In this issue of Cell Host & Microbe, Rice et al. demonstrate that interactions between intestinal commensals reciprocally modulate the host immune response to each microbe, ameliorating the inflammation caused by one and dampening antibody responses to the other.
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Microbioma Gastrointestinal , Microbioma Gastrointestinal/fisiología , Humanos , Inflamación , Intestinos , SimbiosisRESUMEN
Leukemic cells proliferate faster than non-transformed counterparts. This requires them to change their metabolism to adapt to their high growth. This change can stress cells and facilitate recognition by immune cells such as cytotoxic lymphocytes, which express the activating receptor Natural Killer G2-D (NKG2D). The tumor suppressor gene p53 regulates cell metabolism, but its role in the expression of metabolism-induced ligands, and subsequent recognition by cytotoxic lymphocytes, is unknown. We show here that dichloroacetate (DCA), which induces oxidative phosphorylation (OXPHOS) in tumor cells, induces the expression of such ligands, e.g. MICA/B, ULBP1 and ICAM-I, by a wtp53-dependent mechanism. Mutant or null p53 have the opposite effect. Conversely, DCA sensitizes only wtp53-expressing cells to cytotoxic lymphocytes, i.e. cytotoxic T lymphocytes and NK cells. In xenograft in vivo models, DCA slows down the growth of tumors with low proliferation. Treatment with DCA, monoclonal antibodies and NK cells also decreased tumors with high proliferation. Treatment of patients with DCA, or a biosimilar drug, could be a clinical option to increase the effectiveness of CAR T cell or allogeneic NK cell therapies.
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Antineoplásicos , Leucemia , Proteína p53 Supresora de Tumor , Antineoplásicos/metabolismo , Antígenos de Histocompatibilidad Clase I/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Leucemia/inmunología , Leucemia/metabolismo , Ligandos , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Proteína p53 Supresora de Tumor/inmunología , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Solid tumor cells have an altered metabolism that can protect them from cytotoxic lymphocytes. The anti-diabetic drug metformin modifies tumor cell metabolism and several clinical trials are testing its effectiveness for the treatment of solid cancers. The use of metformin in hematologic cancers has received much less attention, although allogeneic cytotoxic lymphocytes are very effective against these tumors. We show here that metformin induces expression of Natural Killer G2-D (NKG2D) ligands (NKG2DL) and intercellular adhesion molecule-1 (ICAM-1), a ligand of the lymphocyte function-associated antigen 1 (LFA-1). This leads to enhance sensitivity to cytotoxic lymphocytes. Overexpression of anti-apoptotic Bcl-2 family members decrease both metformin effects. The sensitization to activated cytotoxic lymphocytes is mainly mediated by the increase on ICAM-1 levels, which favors cytotoxic lymphocytes binding to tumor cells. Finally, metformin decreases the growth of human hematological tumor cells in xenograft models, mainly in presence of monoclonal antibodies that recognize tumor antigens. Our results suggest that metformin could improve cytotoxic lymphocyte-mediated therapy.
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Molécula 1 de Adhesión Intercelular/fisiología , Metformina/farmacología , Neoplasias/tratamiento farmacológico , Animales , Humanos , Células Asesinas Naturales , Masculino , Ratones , Ratones Endogámicos NOD , Células Tumorales CultivadasRESUMEN
Monoclonal antibodies (mAbs) are large size molecules that have demonstrated high therapeutic potential for the treatment of cancer or autoimmune diseases. Despite some excellent results, their intravenous administration results in high plasma concentration. This triggers off-target effects and sometimes poor targeted tissue distribution. To circumvent this issue, we investigated a local controlled-delivery approach using an in situ forming depot technology. Two clinically relevant mAbs, rituximab (RTX) and daratumumab (DARA), were formulated using an injectable technology based on biodegradable PEG-PLA copolymers. The stability and controlled release features of the formulations were investigated. HPLC and mass spectrometry revealed the preservation of the protein structure. In vitro binding of formulated antibodies to their target antigens and to their cellular FcγRIIIa natural killer cell receptor was fully maintained. Furthermore, encapsulated RTX was as efficient as classical intravenous RTX treatment to inhibit the in vivo tumor growth of malignant human B cells in immunodeficient NSG mice. Finally, the intra-articular administration of the formulated mAbs yielded a sustained local release associated with a lower plasma concentration compared to the intra-articular delivery of non-encapsulated mAbs. Our results demonstrate that the utilization of this polymeric technology is a reliable alternative for the local delivery of fully functional clinically relevant mAbs.
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Polímeros , Animales , Preparaciones de Acción Retardada/química , Ratones , Polímeros/químicaRESUMEN
Unconventional T cellsincluding invariant natural killer T (iNKT) cells, mucosal-associated invariant T (MAIT) cells, and defined subsets of γδ T cellsare restricted by monomorphic major histocompatibility complex class Ib (MHC-Ib) molecules and seed tissues during development. Early-life instructive signals, including those derived from the microbiota, establish homeostatic set points for unconventional T cells, a phenomenon that has lifelong consequences for the regulation of tissue immunity, inflammation, and repair. Unconventional T cells compete for niches within tissues, and recent evidence supports the idea that the fundamental role of these cells in tissue physiology may result from their action as a network with overlapping and potentially synergistic functions, rather than as individual subsets.
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Homeostasis , Microbiota , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/fisiología , Animales , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Inmunidad Innata , Inflamación , Microbiota/inmunología , Microbiota/fisiología , Células T Invariantes Asociadas a Mucosa/inmunología , Células T Invariantes Asociadas a Mucosa/fisiología , Células T Asesinas Naturales/inmunología , Células T Asesinas Naturales/fisiologíaRESUMEN
The microbiota plays a fundamental role in regulating host immunity. However, the processes involved in the initiation and regulation of immunity to the microbiota remain largely unknown. Here, we show that the skin microbiota promotes the discrete expression of defined endogenous retroviruses (ERVs). Keratinocyte-intrinsic responses to ERVs depended on cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes protein (STING) signaling and promoted the induction of commensal-specific T cells. Inhibition of ERV reverse transcription significantly impacted these responses, resulting in impaired immunity to the microbiota and its associated tissue repair function. Conversely, a lipid-enriched diet primed the skin for heightened ERV- expression in response to commensal colonization, leading to increased immune responses and tissue inflammation. Together, our results support the idea that the host may have co-opted its endogenous virome as a means to communicate with the exogenous microbiota, resulting in a multi-kingdom dialog that controls both tissue homeostasis and inflammation.
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Retrovirus Endógenos/fisiología , Homeostasis , Inflamación/microbiología , Inflamación/patología , Microbiota , Animales , Bacterias/metabolismo , Cromosomas Bacterianos/genética , Dieta Alta en Grasa , Inflamación/inmunología , Inflamación/virología , Interferón Tipo I/metabolismo , Queratinocitos/metabolismo , Proteínas de la Membrana/metabolismo , Ratones Endogámicos C57BL , Nucleotidiltransferasas/metabolismo , Retroelementos/genética , Transducción de Señal , Piel/inmunología , Piel/microbiología , Linfocitos T/inmunología , Transcripción GenéticaRESUMEN
The lymphocyte lineage natural killer (NK) cell is part of the innate immune system and protects against pathogens and tumor cells. NK cells are the main cell effectors of the monoclonal antibodies (mAbs) that mediates antibody-dependent cell cytotoxicity (ADCC). Hence, it is relevant to understand NK physiology and status to investigate the biological effect of mAbs in the clinic. NK cells are heterogeneous with multiple subsets that may have specific activity against different attacks. The presence of viral-sculpted NK cell populations has already been described, but the presence of cancer-sculpted NK cells remains unknown. Cancer induces a broad NK cell dysfunction, which has not been linked to a specific population. Here, we investigated the NK cell population by Uniform Manifold Approximation and Projection (UMAP) embed maps in Hodgkin lymphoma (HL) and acute myeloid leukemia (AML) patients at diagnosis and at least 30 days after treatment, which correlates with tumor cell clearance. We found that the NK lineage largely responded to the tumor by generating antitumor NK cells and renewing the population with a subset of immature NK cells. However, we failed to identify a specific "memory-like" subset with the NK cell markers used. Moreover, in patients in relapse, we found essentially the same NK populations as those found at diagnosis, suggesting that NK cells equally respond to the first or second tumor rise. Finally, we observed that previous cytomegalovirus (CMV) infection largely affects the tumor-associated changes in NK population, but the CMV-associated CD57+NKG2C+ NK cell population does not appear to play any role in tumor immunity.
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In this study we evaluated the potential of expanded NK cells (eNKs) from two sources combined with the mAbs daratumumab and pembrolizumab to target primary multiple myeloma (MM) cells ex vivo. In order to ascertain the best source of NK cells, we expanded and activated NK cells from peripheral blood (PB) of healthy adult donors and from umbilical cord blood (UCB). The resulting expanded NK (eNK) cells express CD16, necessary for carrying out antibody-dependent cellular cytotoxicity (ADCC). Cytotoxicity assays were performed on bone marrow aspirates of 18 MM patients and 4 patients with monoclonal gammopathy of undetermined significance (MGUS). Expression levels of PD-1 on eNKs and PD-L1 on MM and MGUS cells were also quantified. Results indicate that most eNKs obtained using our expansion protocol express a low percentage of PD-1+ cells. UCB eNKs were highly cytotoxic against MM cells and addition of daratumumab or pembrolizumab did not further increase their cytotoxicity. PB eNKs, while effective against MM cells, were significantly more cytotoxic when combined with daratumumab. In a minority of cases, eNK cells showed a detectable population of PD1+ cells. This correlated with low cytotoxic activity, particularly in UCB eNKs. Addition of pembrolizumab did not restore their activity. Results indicate that UCB eNKs are to be preferentially used against MM in the absence of daratumumab while PB eNKs have significant cytotoxic advantage when combined with this mAb.
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Mieloma Múltiple , Adulto , Anticuerpos Monoclonales/farmacología , Sangre Fetal , Humanos , Células Asesinas Naturales , Mieloma Múltiple/tratamiento farmacológicoRESUMEN
The cross-talk between the microbiota and the immune system plays a fundamental role in the control of host physiology. However, the tissue-specific factors controlling this dialogue remain poorly understood. Here we demonstrate that T cell responses to commensal colonization are associated with the development of organized cellular clusters within the skin epithelium. These organized lymphocyte clusters are surrounded by keratinocytes expressing a discrete program associated with antigen presentation and antimicrobial defense. Notably, IL-22-mediated keratinocyte-intrinsic MHC class II expression was required for the selective accumulation of commensal-induced IFN-γ, but not IL-17A-producing CD4+ T cells within the skin. Taking these data together, this work uncovers an unexpected role for MHC class II expression by keratinocytes in the control of homeostatic type 1 responses to the microbiota. Our findings have important implications for the understanding of the tissue-specific rules governing the dialogue between a host and its microbiota.
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Epidermis/microbiología , Antígenos de Histocompatibilidad Clase II/biosíntesis , Interacciones Microbiota-Huesped/inmunología , Queratinocitos/inmunología , Microbiota/inmunología , Células TH1/inmunología , Animales , Presentación de Antígeno , Candida albicans/inmunología , Epidermis/inmunología , Genes MHC Clase II , Interferón gamma/biosíntesis , Queratinocitos/metabolismo , Ratones , Ratones Endogámicos C57BL , Especificidad de Órganos , Quimera por Radiación , Organismos Libres de Patógenos Específicos , Staphylococcus aureus/inmunología , Staphylococcus epidermidis/inmunología , Simbiosis , Células TH1/metabolismoRESUMEN
How early-life colonization and subsequent exposure to the microbiota affect long-term tissue immunity remains poorly understood. Here, we show that the development of mucosal-associated invariant T (MAIT) cells relies on a specific temporal window, after which MAIT cell development is permanently impaired. This imprinting depends on early-life exposure to defined microbes that synthesize riboflavin-derived antigens. In adults, cutaneous MAIT cells are a dominant population of interleukin-17A (IL-17A)-producing lymphocytes, which display a distinct transcriptional signature and can subsequently respond to skin commensals in an IL-1-, IL-18-, and antigen-dependent manner. Consequently, local activation of cutaneous MAIT cells promotes wound healing. Together, our work uncovers a privileged interaction between defined members of the microbiota and MAIT cells, which sequentially controls both tissue-imprinting and subsequent responses to injury.
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Microbiota/inmunología , Células T Invariantes Asociadas a Mucosa/citología , Riboflavina/biosíntesis , Cicatrización de Heridas/inmunología , Animales , Bacterias/clasificación , Bacterias/metabolismo , Vida Libre de Gérmenes , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Interleucina-1/inmunología , Interleucina-17/inmunología , Interleucina-18/inmunología , Interleucina-23/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/inmunología , Piel/inmunología , Piel/microbiología , Organismos Libres de Patógenos EspecíficosRESUMEN
Tissue accumulation of p16INK4a-positive senescent cells is associated with age-related disorders, such as osteoarthritis (OA). These cell-cycle arrested cells affect tissue function through a specific secretory phenotype. The links between OA onset and senescence remain poorly described. Using experimental OA protocol and transgenic Cdkn2a+/luc and Cdkn2aluc/luc mice, we found that the senescence-driving p16INK4a is a marker of the disease, expressed by the synovial tissue, but is also an actor: its somatic deletion partially protects against cartilage degeneration. We test whether by becoming senescent, the mesenchymal stromal/stem cells (MSCs), found in the synovial tissue and sub-chondral bone marrow, can contribute to OA development. We established an in vitro p16INK4a-positive senescence model on human MSCs. Upon senescence induction, their intrinsic stem cell properties are altered. When co-cultured with OA chondrocytes, senescent MSC show also a seno-suppressive properties impairment favoring tissue degeneration. To evaluate in vivo the effects of p16INK4a-senescent MSC on healthy cartilage, we rely on the SAMP8 mouse model of accelerated senescence that develops spontaneous OA. MSCs isolated from these mice expressed p16INK4a. Intra-articular injection in 2-month-old C57BL/6JRj male mice of SAMP8-derived MSCs was sufficient to induce articular cartilage breakdown. Our findings reveal that senescent p16INK4a-positive MSCs contribute to joint alteration.
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Senescencia Celular/fisiología , Células Madre Mesenquimatosas/fisiología , Osteoartritis/inducido químicamente , Comunicación Paracrina/fisiología , Animales , Proliferación Celular/efectos de los fármacos , Proliferación Celular/fisiología , Células Cultivadas , Senescencia Celular/efectos de los fármacos , Condrocitos/fisiología , Técnicas de Cocultivo , Colagenasas/toxicidad , Etopósido/toxicidad , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inflamación/metabolismo , Luciferasas/metabolismo , Masculino , Células Madre Mesenquimatosas/efectos de los fármacos , Ratones , Ratones Endogámicos , Ratones TransgénicosRESUMEN
The thymus is critical for the establishment of the adaptive immune system and the development of a diverse T cell repertoire. T cell development depends upon cell-cell interactions with epithelial cells in the thymus. The thymus is composed of two different types of epithelial cells: cortical and medullary epithelial cells. Both of these express and critically depend on the transcription factor Foxn1 Foxn1 is also expressed in the hair follicle, and disruption of Foxn1 function in mice results in severe thymic developmental defects and the hairless (nude) phenotype. Despite its importance, little is known about the direct regulation of Foxn1 expression. In this study, we identify a cis-regulatory element (RE) critical for expression of Foxn1 in mouse thymic epithelial cells but dispensable for expression in hair follicles. Analysis of chromatin accessibility, histone modifications, and sequence conservation identified regions within the first intron of Foxn1 that possessed the characteristics of REs. Systematic knockout of candidate regions lead us to identify a 1.6 kb region that, when deleted, results in a near total disruption of thymus development. Interestingly, Foxn1 expression and function in the hair follicle were unaffected. RNA fluorescent in situ hybridization showed a near complete loss of Foxn1 mRNA expression in the embryonic thymic bud. Our studies have identified a genomic RE with thymic-specific control of Foxn1 gene expression.
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Células Epiteliales/metabolismo , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Elementos Reguladores de la Transcripción/genética , Linfocitos T/inmunología , Timo/metabolismo , Animales , Factores de Transcripción Forkhead/biosíntesis , Regulación de la Expresión Génica , Técnicas de Inactivación de Genes , Folículo Piloso/metabolismo , Ratones , Ratones Noqueados , Ratones Desnudos , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Linfocitos T/citología , Timo/citologíaRESUMEN
Our societies are facing with the emergence of an exponential number of patients with age-related degenerative chronic diseases such as osteoarthritis or osteoporosis. The "better" aging will thus be at the center of the next medical challenges in order to delay the loss of independence of the elderly and reduce costs of our health services. Over the last 5 years, based on innovative mouse models or in vitro studies, several research teams have demonstrated that many age-related degenerative diseases have in common a deleterious accumulation of so-called senescent cells in their respective deficient tissues. Thus, under the concept of senolysis, it has been proposed to target pharmacologically in vivo these cells to eliminate them and thus delay the emergence of these chronic diseases of the elderly subject. We propose here to summarize the recent strategies applied for the identification of novel senolytics and their uses in osteoarthritis and osteoporosis therapies.