RESUMO
Most cases of herpes simplex virus 1 (HSV-1) encephalitis (HSE) remain unexplained1,2. Here, we report on two unrelated people who had HSE as children and are homozygous for rare deleterious variants of TMEFF1, which encodes a cell membrane protein that is preferentially expressed by brain cortical neurons. TMEFF1 interacts with the cell-surface HSV-1 receptor NECTIN-1, impairing HSV-1 glycoprotein D- and NECTIN-1-mediated fusion of the virus and the cell membrane, blocking viral entry. Genetic TMEFF1 deficiency allows HSV-1 to rapidly enter cortical neurons that are either patient specific or derived from CRISPR-Cas9-engineered human pluripotent stem cells, thereby enhancing HSV-1 translocation to the nucleus and subsequent replication. This cellular phenotype can be rescued by pretreatment with type I interferon (IFN) or the expression of exogenous wild-type TMEFF1. Moreover, ectopic expression of full-length TMEFF1 or its amino-terminal extracellular domain, but not its carboxy-terminal intracellular domain, impairs HSV-1 entry into NECTIN-1-expressing cells other than neurons, increasing their resistance to HSV-1 infection. Human TMEFF1 is therefore a host restriction factor for HSV-1 entry into cortical neurons. Its constitutively high abundance in cortical neurons protects these cells from HSV-1 infection, whereas inherited TMEFF1 deficiency renders them susceptible to this virus and can therefore underlie HSE.
Assuntos
Encéfalo , Encefalite por Herpes Simples , Herpesvirus Humano 1 , Proteínas de Membrana , Internalização do Vírus , Animais , Feminino , Humanos , Masculino , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/virologia , Encefalite por Herpes Simples/virologia , Encefalite por Herpes Simples/metabolismo , Herpesvirus Humano 1/patogenicidade , Herpesvirus Humano 1/fisiologia , Homozigoto , Interferon Tipo I/metabolismo , Interferon Tipo I/imunologia , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Nectinas/genética , Nectinas/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Neurônios/virologia , Células-Tronco Pluripotentes/citologia , Replicação Viral , Pré-Escolar , Adulto Jovem , LinhagemRESUMO
FMS-related tyrosine kinase 3 ligand (FLT3L), encoded by FLT3LG, is a hematopoietic factor essential for the development of natural killer (NK) cells, B cells, and dendritic cells (DCs) in mice. We describe three humans homozygous for a loss-of-function FLT3LG variant with a history of various recurrent infections, including severe cutaneous warts. The patients' bone marrow (BM) was hypoplastic, with low levels of hematopoietic progenitors, particularly myeloid and B cell precursors. Counts of B cells, monocytes, and DCs were low in the patients' blood, whereas the other blood subsets, including NK cells, were affected only moderately, if at all. The patients had normal counts of Langerhans cells (LCs) and dermal macrophages in the skin but lacked dermal DCs. Thus, FLT3L is required for B cell and DC development in mice and humans. However, unlike its murine counterpart, human FLT3L is required for the development of monocytes but not NK cells.
Assuntos
Células Matadoras Naturais , Proteínas de Membrana , Animais , Feminino , Humanos , Masculino , Camundongos , Linfócitos B/metabolismo , Linfócitos B/citologia , Medula Óssea/metabolismo , Linhagem da Célula , Células Dendríticas/metabolismo , Hematopoese , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/citologia , Células Matadoras Naturais/metabolismo , Células Matadoras Naturais/imunologia , Células de Langerhans/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Monócitos/metabolismo , Pele/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Autoinflammation is a sterile inflammatory process resulting from increased neutrophil infiltration and overexpression of IL-1 cytokines. The factors that trigger these events are, however, poorly understood. By investigating pustular forms of psoriasis, we show that human neutrophils constitutively express IL-26 and abundantly release it from granular stores upon activation. In pustular psoriasis, neutrophil-derived IL-26 drives the pathogenic autoinflammation process by inducing the expression of IL-1 cytokines and chemokines that further recruit neutrophils. This occurs via activation of IL-26R in keratinocytes and via the formation of complexes between IL-26 and microbiota DNA, which trigger TLR9 activation of neutrophils. Thus our findings identify neutrophils as an important source of IL-26 and point to IL-26 as the key link between neutrophils and a self-sustaining autoinflammation loop in pustular psoriasis.
Assuntos
Neutrófilos , Psoríase , Humanos , Interleucinas , Citocinas , Interleucina-1RESUMO
BACKGROUNDWeakly virulent environmental mycobacteria (EM) can cause severe disease in HLA-DRB1*15:02 or 16:02 adults harboring neutralizing anti-IFN-γ autoantibodies (nAIGAs). The overall prevalence of nAIGAs in the general population is unknown, as are the penetrance of nAIGAs in HLA-DRB1*15:02 or 16:02 individuals and the proportion of patients with unexplained, adult-onset EM infections carrying nAIGAs.METHODSThis study analyzed the detection and neutralization of anti-IFN-γ autoantibodies (auto-Abs) from 8,430 healthy individuals of the general population, 257 HLA-DRB1*15:02 or 16:02 carriers, 1,063 patients with autoimmune disease, and 497 patients with unexplained severe disease due to EM.RESULTSWe found that anti-IFN-γ auto-Abs detected in 4,148 of 8,430 healthy individuals (49.2%) from the general population of an unknown HLA-DRB1 genotype were not neutralizing. Moreover, we did not find nAIGAs in 257 individuals carrying HLA-DRB1* 15:02 or 16:02. Additionally, nAIGAs were absent in 1,063 patients with an autoimmune disease. Finally, 7 of 497 patients (1.4%) with unexplained severe disease due to EM harbored nAIGAs.CONCLUSIONThese findings suggest that nAIGAs are isolated and that their penetrance in HLA-DRB1*15:02 or 16:02 individuals is low, implying that they may be triggered by rare germline or somatic variants. In contrast, the risk of mycobacterial disease in patients with nAIGAs is high, confirming that these nAIGAs are the cause of EM disease.FUNDINGThe Laboratory of Human Genetics of Infectious Diseases is supported by the Howard Hughes Medical Institute, the Rockefeller University, the St. Giles Foundation, the National Institutes of Health (NIH) (R01AI095983 and U19AIN1625568), the National Center for Advancing Translational Sciences (NCATS), the NIH Clinical and Translational Science Award (CTSA) program (UL1 TR001866), the French National Research Agency (ANR) under the "Investments for the Future" program (ANR-10-IAHU-01), the Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence (ANR-10-LABX-62-IBEID), ANR-GENMSMD (ANR-16-CE17-0005-01), ANR-MAFMACRO (ANR-22-CE92-0008), ANRSECTZ170784, the French Foundation for Medical Research (FRM) (EQU201903007798), the ANRS-COV05, ANR GENVIR (ANR-20-CE93-003), and ANR AI2D (ANR-22-CE15-0046) projects, the ANR-RHU program (ANR-21-RHUS-08-COVIFERON), the European Union's Horizon 2020 research and innovation program under grant agreement no. 824110 (EASI-genomics), the Square Foundation, Grandir - Fonds de solidarité pour l'enfance, the Fondation du Souffle, the SCOR Corporate Foundation for Science, the Battersea & Bowery Advisory Group, William E. Ford, General Atlantic's Chairman and Chief Executive Officer, Gabriel Caillaux, General Atlantic's Co-President, Managing Director, and Head of business in EMEA, and the General Atlantic Foundation, Institut National de la Santé et de la Recherche Médicale (INSERM) and of Paris Cité University. JR was supported by the INSERM PhD program for doctors of pharmacy (poste d'accueil INSERM). JR and TLV were supported by the Bettencourt-Schueller Foundation and the MD-PhD program of the Imagine Institute. MO was supported by the David Rockefeller Graduate Program, the Funai Foundation for Information Technology (FFIT), the Honjo International Scholarship Foundation (HISF), and the New York Hideyo Noguchi Memorial Society (HNMS).
Assuntos
Autoanticorpos , Doenças Autoimunes , Adulto , Humanos , Predisposição Genética para Doença , Genótipo , Cadeias HLA-DRB1/genética , Infecções por Mycobacterium não TuberculosasRESUMO
Human inherited disorders of interferon-gamma (IFN-γ) immunity underlie severe mycobacterial diseases. We report X-linked recessive MCTS1 deficiency in men with mycobacterial disease from kindreds of different ancestries (from China, Finland, Iran, and Saudi Arabia). Complete deficiency of this translation re-initiation factor impairs the translation of a subset of proteins, including the kinase JAK2 in all cell types tested, including T lymphocytes and phagocytes. JAK2 expression is sufficiently low to impair cellular responses to interleukin-23 (IL-23) and partially IL-12, but not other JAK2-dependent cytokines. Defective responses to IL-23 preferentially impair the production of IFN-γ by innate-like adaptive mucosal-associated invariant T cells (MAIT) and γδ T lymphocytes upon mycobacterial challenge. Surprisingly, the lack of MCTS1-dependent translation re-initiation and ribosome recycling seems to be otherwise physiologically redundant in these patients. These findings suggest that X-linked recessive human MCTS1 deficiency underlies isolated mycobacterial disease by impairing JAK2 translation in innate-like adaptive T lymphocytes, thereby impairing the IL-23-dependent induction of IFN-γ.
Assuntos
Interferon gama , Janus Quinase 2 , Infecções por Mycobacterium , Humanos , Masculino , Proteínas de Ciclo Celular/metabolismo , Interferon gama/imunologia , Interleucina-12 , Interleucina-23 , Janus Quinase 2/metabolismo , Mycobacterium/fisiologia , Infecções por Mycobacterium/imunologia , Infecções por Mycobacterium/metabolismo , Proteínas Oncogênicas/metabolismoRESUMO
BACKGROUND: A popular antiseptic spray in Switzerland (Merfen spray), containing chlorhexidine digluconate, benzoxonium chloride and lauramine oxide, is frequently used to treat skin wounds. However, it is also increasingly reported as a major cause of adverse skin reactions, including allergic contact dermatitis (ACD). OBJECTIVES: To investigate the contact allergens responsible for ACD from this antiseptic. PATIENTS/METHODS: Patch tests were performed on seven patients with a clinical history compatible with contact dermatitis from this antiseptic mixture. RESULTS: All patients presented with acute eczematous reactions following contact with either Merfen spray alone, or with multiple products including this spray. Patients showed positive reactions to this product in both patch tests and repeated open application tests (ROATs). Four patients showed dose-dependent reactions to both benzoxonium chloride and lauramine oxide. One patient showed a dose-dependent reaction to the former and a non-dose-dependent reaction to the latter. Finally, two subjects showed responses only to lauramine oxide. One patient reacted to chlorhexidine digluconate 0.5% aq. in addition to both other allergens. CONCLUSIONS: Two commercially unavailable allergens, that is, benzoxonium chloride and/or lauramine oxide were identified as major causes of ACD from Merfen antiseptic spray, whereas chlorhexidine digluconate was a contributing culprit in only one patient.
Assuntos
Anti-Infecciosos Locais , Dermatite Alérgica de Contato , Humanos , Anti-Infecciosos Locais/efeitos adversos , Clorexidina/efeitos adversos , Alérgenos/efeitos adversos , Dermatite Alérgica de Contato/diagnóstico , Dermatite Alérgica de Contato/etiologia , Suíça , Testes do Emplastro/efeitos adversos , ÓxidosRESUMO
Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the single-stranded RNA-degrading ribonuclease L (RNase L). Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-deficient but not RNase L-deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by mitochondrial antiviral-signaling protein (MAVS) deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C.
Assuntos
COVID-19 , Citocinas , Endorribonucleases , SARS-CoV-2 , Síndrome de Resposta Inflamatória Sistêmica , Criança , Humanos , COVID-19/imunologia , Citocinas/genética , Citocinas/imunologia , Endorribonucleases/genética , Endorribonucleases/metabolismo , RNA de Cadeia Dupla , SARS-CoV-2/genética , Síndrome de Resposta Inflamatória Sistêmica/genéticaRESUMO
COVID-19, which is caused by infection with SARS-CoV-2, is characterized by lung pathology and extrapulmonary complications1,2. Type I interferons (IFNs) have an essential role in the pathogenesis of COVID-19 (refs 3-5). Although rapid induction of type I IFNs limits virus propagation, a sustained increase in the levels of type I IFNs in the late phase of the infection is associated with aberrant inflammation and poor clinical outcome5-17. Here we show that the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which controls immunity to cytosolic DNA, is a critical driver of aberrant type I IFN responses in COVID-19 (ref. 18). Profiling COVID-19 skin manifestations, we uncover a STING-dependent type I IFN signature that is primarily mediated by macrophages adjacent to areas of endothelial cell damage. Moreover, cGAS-STING activity was detected in lung samples from patients with COVID-19 with prominent tissue destruction, and was associated with type I IFN responses. A lung-on-chip model revealed that, in addition to macrophages, infection with SARS-CoV-2 activates cGAS-STING signalling in endothelial cells through mitochondrial DNA release, which leads to cell death and type I IFN production. In mice, pharmacological inhibition of STING reduces severe lung inflammation induced by SARS-CoV-2 and improves disease outcome. Collectively, our study establishes a mechanistic basis of pathological type I IFN responses in COVID-19 and reveals a principle for the development of host-directed therapeutics.
Assuntos
COVID-19/imunologia , COVID-19/patologia , Interferon Tipo I/imunologia , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/metabolismo , SARS-CoV-2/imunologia , Animais , COVID-19/metabolismo , COVID-19/virologia , Células Cultivadas , DNA Mitocondrial/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Células Endoteliais/patologia , Feminino , Regulação da Expressão Gênica/imunologia , Humanos , Imunidade Inata , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Pulmão/virologia , Macrófagos/imunologia , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Pneumonia/imunologia , Pneumonia/metabolismo , Pneumonia/patologia , Pneumonia/virologia , SARS-CoV-2/patogenicidade , Transdução de Sinais , Pele/imunologia , Pele/metabolismo , Pele/patologiaRESUMO
Heavy metal pollution in the environment is a major concern for humans as it is non-biodegradable and can have a lot of effects on the environment, humans as well as plants. At present, a solution to this problem is suggested in terms of a new, innovative and eco-friendly technology known as phytoremediation. Bast fiber plants are typically non-edible crops that have a short life cycle. It is one of the significant crops that has attracted interest for many industrial uses because of its constant fiber supply and ease of maintenance. Due to its low maintenance requirements with minimum economic investment, bast fiber plants have been widely used in phytoremediation. Nevertheless, these plants have the ability to extract metals from the soil through their deep roots, combined with their commercial prospects, making them an ideal candidate as a profit-yielding crop for phytoremediation purposes. Therefore, a comprehensive review is needed for a better understanding of the morphology and phytoremediation mechanism of four commonly bast fiber plants, such as hemp (Cannabis sativa), kenaf (Hibiscus cannabinus), jute (Corchorus olitorius) and Flax (Linum usitatissimum). This review article summarizes the existing research on the phytoremediation potential of these plants grown in different toxic pollutants such as Lead (Pb), Cadmium (Cd) and Zinc (Zn). This work also discusses several aids including natural and chemical amendments to improve phytoremediation. The role of these amendments in the bioavailability of contaminants, their uptake, translocation and bioaccumulation, as well as their effect on plant growth and development, has been highlighted in this paper. This paper helps in identifying, comparing and addressing the recent achievements of bast fiber plants for the phytoremediation of heavy metals in contaminated soil.
RESUMO
This study aims to examine the relationship between daily temperature and mortality in the Klang Valley, Malaysia, over the period 2006-2015. A quasi-Poisson generalized linear model combined with a distributed lag non-linear model (DLNM) was used to estimate the association between the mean temperature and mortality categories (natural n=69,542, cardiovascular n= 15,581, and respiratory disease n=10,119). Particulate matter with an aerodynamic diameter below 10 µm (PM10) and surface ozone (O3) was adjusted as a potential confounding factor. The relative risk (RR) of natural mortality associated with extreme cold temperature (1st percentile of temperature, 25.2 °C) over lags 0-28 days was 1.26 (95% confidence interval (CI): 1.00, 1.60), compared with the minimum mortality temperature (28.2 °C). The relative risk associated with extremely hot temperature (99th percentile of temperature, 30.2 °C) over lags 0-3 days was 1.09 (95% CI: 1.02, 1.17). Heat effects were immediate whereas cold effects were delayed and lasted longer. People with respiratory diseases, the elderly, and women were the most vulnerable groups when it came to the effects of extremely high temperatures. Extreme temperatures did not dramatically change the temperature-mortality risk estimates made before and after adjustments for air pollutant (PM10 and O3) levels.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Idoso , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Causas de Morte , Temperatura Baixa , Feminino , Temperatura Alta , Humanos , Malásia , Mortalidade , TemperaturaRESUMO
Since the beginning of the COVID-19 pandemic, dermatologists around the world have reported patients with chilblain-like skin lesions on their toes, called COVID-toes. Surprisingly, the majority of these patients do not develop COVID-19 symptoms, and their nasal swabs and serological tests are unable to confirm SARS-CoV-2 infection, despite a clear exposure to the virus. Recent evidence suggests that these patients mount a robust type I interferon response to SARS-CoV-2, making them resistant to the infection. Because chilblains are hallmarks of excessive type I interferons, COVID-toes may represent the skin expression of interferon-mediated resistance to SARS-CoV-2. Uncovering the molecular patho-mechanisms of COVID-toes may provide new avenues to promote SARS-CoV-2 resistance and control the COVID-19 pandemic.
Depuis le début de la pandémie de Covid-19, les dermatologues du monde entier ont signalé des cas inexpliqués de pseudo-engelures, surnommées «â orteils Covidâ ¼ (COVID-toes). Cette recrudescence inhabituelle de pseudo-engelures est d'autant plus intrigante que la majorité des cas ne présentent pas de symptômes de Covid-19 ni de PCR ou de sérologie positive, malgré une exposition probable au SARS-CoV-2. Les données actuelles suggèrent que ces personnes sont prédisposées à induire une immunité innée robuste contre le SARS-CoV-2, ce qui les rend résistantes à l'infection. Une forte réponse interféron de type I, dont les pseudo-engelures sont l'expression clinique, pourrait favoriser une clairance rapide du virus, évitant à la fois la maladie et la séroconversion. Les mécanismes génétiques et moléculaires qui sous-tendent cette résistance naturelle au SARS-CoV-2 restent cependant à élucider.
Assuntos
COVID-19 , Pérnio , Pérnio/epidemiologia , Humanos , Pandemias , SARS-CoV-2 , Dedos do PéRESUMO
A 64-year-old patient developed a widespread autoimmune mucocutaneous blistering disease 3 weeks after the initiation of the anti-programmed death-1 (anti-PD-1) pembrolizumab therapy administered for a locally advanced cutaneous squamous cell carcinoma (SCC) of the buttocks arising from hidradenitis suppurativa. A diagnosis of paraneoplastic pemphigus (PNP) was made based on the presence of a suprabasal acantholysis associated with intercellular deposits of immunoglobulin G and C3 on basement membrane zone. Analysis of the patient's sera was positive on monkey bladder and detected circulating antibodies against desmoglein 3 and desmoplakin I prior to the initiation of pembrolizumab. At that time, the patient had few localized blisters limited to the peri-tumoral skin of the buttocks with acantholysis but without in vivo immune deposits. Pembrolizumab therapy was discontinued and a complete remission of PNP was obtained using oral steroids. Reintroduction of pembrolizumab resulted in flare of PNP. Given the close temporal relation between pembrolizumab initiation and the subsequent clinical expression of a widespread PNP, the patient was diagnosed with pre-existing subclinical PNP exacerbated by PD-1 inhibitor. The extreme rarity of PNP in the setting of cutaneous SCC and the effects of challenge, dechallenge, and rechallenge of pembrolizumab argue in favor of a checkpoint inhibitor related adverse effect. Our case is the first PNP associated with anti-PD-1 therapy and serological follow-up suggest that one infusion of pembrolizumab is sufficient to allow clinical expression of underlying pemphigus auto-immunity.
RESUMO
The HIV auxiliary protein Vpr potently blocks the cell cycle at the G2/M transition. Here, we show that G2/M arrest results from untimely activation of the structure-specific endonuclease (SSE) regulator SLX4 complex (SLX4com) by Vpr, a process that requires VPRBP-DDB1-CUL4 E3-ligase complex. Direct interaction of Vpr with SLX4 induced the recruitment of VPRBP and kinase-active PLK1, enhancing the cleavage of DNA by SLX4-associated MUS81-EME1 endonucleases. G2/M arrest-deficient Vpr alleles failed to interact with SLX4 or to induce recruitment of MUS81 and PLK1. Furthermore, knockdown of SLX4, MUS81, or EME1 inhibited Vpr-induced G2/M arrest. In addition, we show that the SLX4com is involved in suppressing spontaneous and HIV-1-mediated induction of type 1 interferon and establishment of antiviral responses. Thus, our work not only reveals the identity of the cellular factors required for Vpr-mediated G2/M arrest but also identifies the SLX4com as a regulator of innate immunity.
Assuntos
Pontos de Checagem da Fase G2 do Ciclo Celular , Infecções por HIV/patologia , HIV-1/metabolismo , Imunidade Inata , Complexos Multiproteicos/metabolismo , Recombinases/metabolismo , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/metabolismo , Proteínas de Ligação a DNA/metabolismo , Endodesoxirribonucleases/metabolismo , Endonucleases/metabolismo , Células HEK293 , Infecções por HIV/imunologia , Infecções por HIV/virologia , Células HeLa , Humanos , Interferon gama/metabolismoRESUMO
The mechanisms by which Regulatory T cells suppress IL-2 production of effector CD4+ T cells in pathological conditions are unclear. A subpopulation of human Treg expresses the ectoenzyme CD39, which in association with CD73 converts ATP/ADP/AMP to adenosine. We show here that Treg/CD39+ suppress IL-2 expression of activated CD4+ T-cells more efficiently than Treg/CD39-. This inhibition is due to the demethylation of an essential CpG site of the il-2 gene promoter, which was reversed by an anti-CD39 mAb. By recapitulating the events downstream CD39/adenosine receptor (A2AR) axis, we show that A2AR agonist and soluble cAMP inhibit CpG site demethylation of the il-2 gene promoter. A high frequency of Treg/CD39+ is associated with a low clinical outcome in HIV infection. We show here that CD4+ T-cells from HIV-1 infected individuals express high levels of A2AR and intracellular cAMP. Following in vitro stimulation, these cells exhibit a lower degree of demethylation of il-2 gene promoter associated with a lower expression of IL-2, compared to healthy individuals. These results extend previous data on the role of Treg in HIV infection by filling the gap between expansion of Treg/CD39+ in HIV infection and the suppression of CD4+ T-cell function through inhibition of IL-2 production.
Assuntos
Antígenos CD/metabolismo , Apirase/metabolismo , Infecções por HIV/imunologia , Interleucina-2/biossíntese , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , 5'-Nucleotidase/metabolismo , Adenosina/metabolismo , Anticorpos Monoclonais/imunologia , Antígenos CD/biossíntese , Antígenos CD/imunologia , Apirase/biossíntese , Apirase/imunologia , Proliferação de Células , AMP Cíclico/metabolismo , Metilação de DNA , HIV-1/imunologia , Humanos , Interleucina-2/genética , Ativação Linfocitária , Regiões Promotoras Genéticas , Receptor A2A de Adenosina/metabolismo , Subpopulações de Linfócitos T/metabolismoRESUMO
BACKGROUND: Quiescent CD4+ T lymphocytes are highly refractory to HIV-1 infection due to a block at reverse transcription. RESULTS: Examination of SAMHD1 expression in peripheral blood lymphocytes shows that SAMHD1 is expressed in both CD4+ and CD8+ T cells at levels comparable to those found in myeloid cells. Treatment of CD4+ T cells with Virus-Like Particles (VLP) containing Vpx results in the loss of SAMHD1 expression that correlates with an increased permissiveness to HIV-1 infection and accumulation of reverse transcribed viral DNA without promoting transcription from the viral LTR. Importantly, CD4+ T-cells from patients with Aicardi-Goutières Syndrome harboring mutation in the SAMHD1 gene display an increased susceptibility to HIV-1 infection that is not further enhanced by VLP-Vpx-treatment. CONCLUSION: Here, we identified SAMHD1 as the restriction factor preventing efficient viral DNA synthesis in non-cycling resting CD4+ T-cells. These results highlight the crucial role of SAMHD1 in mediating restriction of HIV-1 infection in quiescent CD4+ T-cells and could impact our understanding of HIV-1 mediated CD4+ T-cell depletion and establishment of the viral reservoir, two of the HIV/AIDS hallmarks.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , HIV-1/imunologia , HIV-1/patogenicidade , Interações Hospedeiro-Patógeno , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Transcrição Reversa , DNA Viral/metabolismo , Humanos , Proteínas Monoméricas de Ligação ao GTP/imunologia , Proteína 1 com Domínio SAM e Domínio HD , Proteínas Virais Reguladoras e Acessórias/imunologia , Proteínas Virais Reguladoras e Acessórias/metabolismoRESUMO
Activating mutations in NOTCH1, an essential regulator of T cell development, are frequently found in human T cell acute lymphoblastic leukemia (T-ALL). Despite important advances in our understanding of Notch signal transduction, the regulation of Notch functions in the nucleus remains unclear. Using immunoaffinity purification, we identified NOTCH1 nuclear partners in T-ALL cells and showed that, beyond the well-characterized core activation complex (ICN1-CSL-MAML1), NOTCH1 assembles a multifunctional complex containing the transcription coactivator AF4p12, the PBAF nucleosome remodeling complex, and the histone demethylases LSD1 and PHF8 acting through their demethylase activity to promote epigenetic modifications at Notch-target genes. Remarkably, LSD1 functions as a corepressor when associated with CSL-repressor complex and as a NOTCH1 coactivator upon Notch activation. Our work provides new insights into the molecular mechanisms that govern Notch transcriptional activity and represents glimpse into NOTCH1 interaction landscape, which will help in deciphering mechanisms of NOTCH1 functions and regulation.
Assuntos
Proteínas Oncogênicas/metabolismo , Receptor Notch1/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Animais , Linhagem Celular Tumoral , Núcleo Celular/genética , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação Leucêmica da Expressão Gênica , Células HEK293 , Células HeLa , Histona Desmetilases/genética , Histona Desmetilases/metabolismo , Humanos , Immunoblotting , Camundongos , Camundongos SCID , Modelos Genéticos , Proteínas Oncogênicas/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Ligação Proteica , Interferência de RNA , Receptor Notch1/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Transplante HeterólogoRESUMO
The primate lentivirus auxiliary protein Vpx counteracts an unknown restriction factor that renders human dendritic and myeloid cells largely refractory to HIV-1 infection. Here we identify SAMHD1 as this restriction factor. SAMHD1 is a protein involved in Aicardi-Goutières syndrome, a genetic encephalopathy with symptoms mimicking congenital viral infection, that has been proposed to act as a negative regulator of the interferon response. We show that Vpx induces proteasomal degradation of SAMHD1. Silencing of SAMHD1 in non-permissive cell lines alleviates HIV-1 restriction and is associated with a significant accumulation of viral DNA in infected cells. Concurrently, overexpression of SAMHD1 in sensitive cells inhibits HIV-1 infection. The putative phosphohydrolase activity of SAMHD1 is probably required for HIV-1 restriction. Vpx-mediated relief of restriction is abolished in SAMHD1-negative cells. Finally, silencing of SAMHD1 markedly increases the susceptibility of monocytic-derived dendritic cells to infection. Our results demonstrate that SAMHD1 is an antiretroviral protein expressed in cells of the myeloid lineage that inhibits an early step of the viral life cycle.
Assuntos
Células Dendríticas/metabolismo , HIV-1/fisiologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Células Mieloides/metabolismo , Proteínas Virais Reguladoras e Acessórias/metabolismo , Linhagem Celular , DNA Viral/metabolismo , Células Dendríticas/virologia , Inativação Gênica , Infecções por HIV/metabolismo , Células HeLa , Humanos , Proteínas Monoméricas de Ligação ao GTP/genética , Células Mieloides/virologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteína 1 com Domínio SAM e Domínio HD , Células U937 , Replicação ViralRESUMO
HIV-1 transactivator Tat has greatly contributed to our understanding of transcription elongation by RNAPII. We purified HIV-1 Tat-associated factors from HeLa nuclear extract and show that Tat forms two distinct and stable complexes. Tatcom1 consists of the core active P-TEFb, MLL-fusion partners involved in leukemia (AF9, AFF4, AFF1, ENL, and ELL), and PAF1 complex. Importantly, Tatcom1 formation relies on P-TEFb while optimal CDK9 CTD-kinase activity is AF9 dependent. MLL-fusion partners and PAF1 are required for Tat transactivation. Tatcom2 is composed of CDK9, CycT1, and 7SK snRNP lacking HEXIM. Tat remodels 7SK snRNP by interacting directly with 7SK RNA, leading to the formation of a stress-resistant 7SK snRNP particle. Besides the identification of factors required for Tat transactivation and important for P-TEFb function, our data show a coordinated control of RNAPII elongation by different classes of transcription elongation factors associated in a single complex and acting at the same promoter.
Assuntos
Núcleo Celular/metabolismo , HIV-1/genética , RNA Viral/biossíntese , Ribonucleoproteínas Nucleares Pequenas/metabolismo , Ativação Transcricional , Produtos do Gene tat do Vírus da Imunodeficiência Humana/metabolismo , Sítios de Ligação , Linhagem Celular , Quinase 9 Dependente de Ciclina/metabolismo , Proteínas de Ligação a DNA/metabolismo , HIV-1/metabolismo , Células HeLa , Histona-Lisina N-Metiltransferase , Humanos , Complexos Multiproteicos , Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Fator B de Elongação Transcricional Positiva/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/metabolismo , Ribonucleoproteínas Nucleares Pequenas/genética , Estresse Fisiológico , Fatores de Transcrição , Fatores de Elongação da Transcrição/metabolismo , Transfecção , Produtos do Gene tat do Vírus da Imunodeficiência Humana/genéticaRESUMO
Notch and IL-7 are both well-characterized factors involved in T-cell development. In contrast to the mouse model, their precise requirements in the differentiation and/or proliferation of various stages of human thymic development have not been fully explored. Here, we demonstrate that IL-7 alone is sufficient to induce the differentiation of ex vivo purified CD34(+) triple negative (TN) surface (s) CD3(-) CD4(-)CD8(-) (CD3(-)CD4(-)CD8(-)), CD4 immature single positive (ISP) (sCD3(-)CD4(+)CD8(-)) and double positive (DP) (sCD3(-)CD4(+)CD8(+)) human thymic precursors to mature DP expressing sCD3 (sCD3(+)CD4(+)CD8(+)). We show that activation of Notch signaling by its ligands Delta-1 or Delta-4 potentiates IL-7-driven proliferation and survival of CD34(+) TN and to a lesser extent of CD4(+) ISP precursors. This effect of Notch is related to a sustained induction of IL-7 receptor alpha chain expression on thymocytes through a decreased methylation of its gene promoter. Thus, we show here that proliferation and differentiation of T-cell precursors are differentially modulated by IL-7 depending on the presence or absence of external signals. These results may have important implications for the clinical use of this cytokine as a strategy aimed at improving immune restoration.
Assuntos
Diferenciação Celular/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Interleucina-7/imunologia , Proteínas de Membrana/imunologia , Receptores Notch/imunologia , Linfócitos T/imunologia , Proteínas Adaptadoras de Transdução de Sinal , Antígenos CD34/imunologia , Proteínas de Ligação ao Cálcio , Diferenciação Celular/efeitos dos fármacos , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/imunologia , Citometria de Fluxo , Humanos , Imunofenotipagem , Lactente , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Interleucina-7/farmacologia , Subunidade alfa de Receptor de Interleucina-7/biossíntese , Subunidade alfa de Receptor de Interleucina-7/imunologia , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas de Membrana/farmacologia , Receptores de Interleucina-7/genética , Receptores de Interleucina-7/imunologia , Transdução de Sinais , Linfócitos T/efeitos dos fármacosRESUMO
In this article, myocardial perfusion in patients with a totally occluded left anterior descending artery reinjected by a normal right coronary artery is assessed using stress single photon emission computed tomography (SPECT). In all, 20 patients, with a totally occluded left anterior descending artery reinjected by normal right coronary artery, underwent myocardial single photon emission computed tomography imaging within 60 days of angiography. All patients had abnormal perfusion single photon emission computed tomography results and 70% had reversible defects. Perfusion defects at rest were present in 75% of patients, with perinecrotic residual ischemia in 45% of patients whereas for 30% of patients, no viable myocardium was detected in the collateral-dependent segments. In all, 25% of patients had no resting perfusion defects but all are presented with stress-induced ischemia. Collaterals are not protective against stress-induced ischemia, but they can preserve myocardial viability. This conclusion is highly supported by the presence of residual ischemia in the collateral-dependent segments.