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1.
J Clin Med ; 13(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38731130

RESUMO

Over the last four decades, the Fontan operation has been the treatment of choice for children born with complex congenital heart diseases and a single-ventricle physiology. However, therapeutic options remain limited and despite ongoing improvements in initial surgical repair, patients still experience a multiplicity of cardiovascular complications. The causes for cardiovascular failure are multifactorial and include systemic ventricular dysfunction, pulmonary vascular resistance, atrioventricular valve regurgitation, arrhythmia, development of collaterals, protein-losing enteropathy, hepatic dysfunction, and plastic bronchitis, among others. The mechanisms leading to these late complications remain to be fully elucidated. Experimental animal models have been developed as preclinical steps that enable a better understanding of the underlying pathophysiology. They furthermore play a key role in the evaluation of the efficacy and safety of new medical devices prior to their use in human clinical studies. However, these experimental models have several limitations. In this review, we aim to provide an overview of the evolution and progress of the various types of experimental animal models used in the Fontan procedure published to date in the literature. A special focus is placed on experimental studies performed on animal models of the Fontan procedure with or without mechanical circulatory support as well as a description of their impact in the evolution of the Fontan design. We also highlight the contribution of animal models to our understanding of the pathophysiology and assess forthcoming developments that may improve the contribution of animal models for the testing of new therapeutic solutions.

2.
Cell Death Dis ; 14(3): 213, 2023 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-36966139

RESUMO

Familial Mediterranean Fever (FMF) is the most common monogenic autoinflammatory disorder. FMF is caused by mutations in the MEFV gene, encoding pyrin, an inflammasome sensor. The best characterized pathogenic mutations associated with FMF cluster in exon 10. Yet, mutations have been described along the whole MEFV coding sequence. Exon 10 encodes the B30.2 domain of the pyrin protein, but the function of this human-specific domain remains unclear. Pyrin is an inflammasome sensor detecting RhoA GTPase inhibition following exposure to bacterial toxins such as TcdA. Here, we demonstrate that the B30.2 domain is dispensable for pyrin inflammasome activation in response to this toxin. Deletion of the B30.2 domain mimics the most typical FMF-associated mutation and confers spontaneous inflammasome activation in response to pyrin dephosphorylation. Our results indicate that the B30.2 domain is a negative regulator of the pyrin inflammasome that acts independently from and downstream of pyrin dephosphorylation. In addition, we identify the central helical scaffold (CHS) domain of pyrin, which lies immediately upstream of the B30.2 domain as a second regulatory domain. Mutations affecting the CHS domain mimic pathogenic mutations in the B30.2 domain and render the pyrin inflammasome activation under the sole control of the dephosphorylation. In addition, specific mutations in the CHS domain strongly increase the cell susceptibility to steroid catabolites, recently described to activate pyrin, in both a cell line model and in monocytes from genotype-selected FMF patients. Taken together, our work reveals the existence of two distinct regulatory regions at the C-terminus of the pyrin protein, that act in a distinct manner to regulate positively or negatively inflammasome activation. Furthermore, our results indicate that different mutations in pyrin regulatory domains have different functional impacts on the pyrin inflammasome which could contribute to the diversity of pyrin-associated autoinflammatory diseases.


Assuntos
Febre Familiar do Mediterrâneo , Inflamassomos , Pirina , Humanos , Febre Familiar do Mediterrâneo/genética , Febre Familiar do Mediterrâneo/metabolismo , Inflamassomos/genética , Inflamassomos/metabolismo , Mutação , Pirina/genética , Pirina/metabolismo
3.
Cell Rep ; 41(2): 111472, 2022 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-36223753

RESUMO

The pyrin inflammasome acts as a guard of RhoA GTPases and is central to immune defenses against RhoA-manipulating pathogens. Pyrin activation proceeds in two steps. Yet, the second step is still poorly understood. Using cells constitutively activated for the pyrin step 1, a chemical screen identifies etiocholanolone and pregnanolone, two catabolites of testosterone and progesterone, acting at low concentrations as specific step 2 activators. High concentrations of these metabolites fully and rapidly activate pyrin, in a human specific, B30.2 domain-dependent manner and without inhibiting RhoA. Mutations in MEFV, encoding pyrin, cause two distinct autoinflammatory diseases pyrin-associated autoinflammation with neutrophilic dermatosis (PAAND) and familial Mediterranean fever (FMF). Monocytes from PAAND patients, and to a lower extent from FMF patients, display increased responses to these metabolites. This study identifies an unconventional pyrin activation mechanism, indicates that endogenous steroid catabolites can drive autoinflammation, through the pyrin inflammasome, and explains the "steroid fever" described in the late 1950s upon steroid injection in humans.


Assuntos
Febre Familiar do Mediterrâneo , Inflamassomos , Pirina , Etiocolanolona , Febre Familiar do Mediterrâneo/genética , Febre Familiar do Mediterrâneo/metabolismo , Humanos , Inflamassomos/metabolismo , Mutação , Pregnanolona , Progesterona , Pirina/genética , Pirina/metabolismo , Testosterona
4.
JACC Case Rep ; 3(12): 1453-1455, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34557691

RESUMO

Congenital left ventricular (LV) diverticulum is a rare condition characterized by the presence of a contractile appendix originating usually from the cardiac apex, but with high variability in location, dimension, and clinical presentation. We describe the diagnostic process and clinical management of an isolated apical diverticulum discovered during fetal life. (Level of Difficulty: Advanced.).

5.
Arch Cardiovasc Dis ; 114(5): 364-370, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33541832

RESUMO

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak had a direct impact on adult cardiac surgery activity, which systematically necessitates a postoperative stay in intensive care. AIM: To study the effect of the COVID-19 lockdown on cardiac surgery activity and outcomes, by making a comparison with the corresponding period in 2019. METHODS: This prospective observational cohort study compared adult cardiac surgery activity in our high-volume referral university hospital from 9 March to 10 May 2020 versus 9 March to 10 May 2019. Data were collected in our local certified database and a national database sponsored by the French society of thoracic and cardiovascular surgery. The primary study endpoints were operative mortality and postoperative complications. RESULTS: With 105 interventions in 2020, our activity dropped by 57% compared with the same period in 2019. Patients were at higher risk, with a significantly higher EuroSCORE II score (3.8±4.5% vs. 2.0±1.8%; P<0.001) and higher rates of active endocarditis (7.6% vs. 2.9%; P=0.047) and recent myocardial infarction (9.5% vs. 0%; P<0.001). The weight and priority of the interventions were significantly different in 2020 (P=0.019 and P<0.001, respectively). The rate of acute aortic syndromes was also significantly higher in 2020 (P<0.001). Operative mortality was higher during the lockdown period (5.7% vs. 1.7%; P=0.038). The postoperative course was more complicated in 2020, with more postoperative bleeding (P=0.003), mechanical circulatory support (P=0.032) and prolonged mechanical ventilation (P=0.005). Only two patients (1.8%) developed a positive status for severe acute respiratory syndrome coronavirus 2 after discharge. CONCLUSIONS: Adult cardiac surgery was heavily affected by the COVID-19 lockdown. A further modulation plan is necessary to improve outcomes and reduce postponed operations to decrease operative mortality and morbidity.


Assuntos
COVID-19/epidemiologia , Procedimentos Cirúrgicos Cardíacos , Hospitais com Alto Volume de Atendimentos/estatística & dados numéricos , Pandemias , Quarentena , SARS-CoV-2 , Idoso , Conversão de Leitos/estatística & dados numéricos , Procedimentos Cirúrgicos Cardíacos/mortalidade , Procedimentos Cirúrgicos Cardíacos/estatística & dados numéricos , Comorbidade , Infecção Hospitalar/epidemiologia , Grupos Diagnósticos Relacionados , Procedimentos Cirúrgicos Eletivos/mortalidade , Procedimentos Cirúrgicos Eletivos/estatística & dados numéricos , Feminino , França/epidemiologia , Cardiopatias/epidemiologia , Cardiopatias/cirurgia , Hospitais Universitários/estatística & dados numéricos , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Utilização de Procedimentos e Técnicas , Estudos Prospectivos , Sala de Recuperação/estatística & dados numéricos , Tempo para o Tratamento , Listas de Espera
6.
Emerg Microbes Infect ; 10(1): 277-290, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33538648

RESUMO

Francisella tularensis, a tier 1 select agent, is the causative bacterium of tularemia, a zoonosis with a large animal reservoir. However, F. tularensis, like many other Francisella species, is assumed to have an aquatic reservoir. The mechanisms of Francisella species persistence in surface water remain poorly characterized. In this study, we deeply investigated the long-term interactions of the tularemia agent F. tularensis subsp. holarctica, F. novicida or F. philomiragia with amoebae of the Acanthamoeba species. In amoeba plate screening tests, all the Francisella species tested resisted the attack by amoebae. In in vitro infection models, intra-amoebic growth of Francisella varied according to the involved bacterial species and strains, but also the amoeba culture medium used. In co-culture models, the amoebae favoured Francisella survival over 16 days, which was likely dependent on direct contact between bacteria and amoebae for F. novicida and on amoeba-excreted compounds for F. novicida and for F. tularensis. In a spring water co-culture model, amoebae again enhanced F. novicida survival and preserved bacterial morphology. Overall, our results demonstrate that amoebae likely promote Francisella survival in aquatic environments, including the tularemia agent F. tularensis. However, bacteria-amoebae interactions are complex and depend on the Francisella species considered.


Assuntos
Amoeba/microbiologia , Francisella tularensis/crescimento & desenvolvimento , Água Doce/microbiologia , Viabilidade Microbiana
7.
Front Cell Infect Microbiol ; 11: 784101, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35004352

RESUMO

Francisella tularensis is a facultative intracellular bacterium and the etiological agent of tularemia, a zoonotic disease. Infection of monocytic cells by F. tularensis can be controlled after activation with IFN-γ; however, the molecular mechanisms whereby the control is executed are incompletely understood. Recently, a key role has been attributed to the Guanylate-binding proteins (GBPs), interferon-inducible proteins involved in the cell-specific immunity against various intracellular pathogens. Here, we assessed the responses of bone marrow-derived murine macrophages (BMDM) and GBP-deficient BMDM to F. tularensis strains of variable virulence; the highly virulent SCHU S4 strain, the human live vaccine strain (LVS), or the widely used surrogate for F. tularensis, the low virulent F. novicida. Each of the strains multiplied rapidly in BMDM, but after addition of IFN-γ, significant GBP-dependent control of infection was observed for the LVS and F. novicida strains, whereas there was no control of the SCHU S4 infection. However, no differences in GBP transcription or translation were observed in the infected cell cultures. During co-infection with F. novicida and SCHU S4, significant control of both strains was observed. Patterns of 18 cytokines were very distinct between infected cell cultures and high levels were observed for almost all cytokines in F. novicida-infected cultures and very low levels in SCHU S4-infected cultures, whereas levels in co-infected cultures for a majority of cytokines showed intermediate levels, or levels similar to those of F. novicida-infected cultures. We conclude that the control of BMDM infection with F. tularensis LVS or F. novicida is GBP-dependent, whereas SCHU S4 was only controlled during co-infection. Since expression of GBP was similar regardless of infecting agent, the findings imply that SCHU S4 has an inherent ability to evade the GBP-dependent anti-bacterial mechanisms.


Assuntos
Francisella tularensis , Macrófagos/imunologia , Tularemia , Animais , Vacinas Bacterianas , Proteínas de Transporte , Células Cultivadas , Humanos , Camundongos , Tularemia/imunologia , Virulência
8.
Ann Rheum Dis ; 80(1): 128-132, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33037005

RESUMO

BACKGROUND AND OBJECTIVE: Familial Mediterranean fever (FMF) is the most frequent hereditary autoinflammatory disease. Its diagnosis relies on a set of clinical criteria and a genetic confirmation on identification of biallelic pathogenic MEFV variants. MEFV encodes pyrin, an inflammasome sensor. Using a kinase inhibitor, UCN-01, we recently identified that dephosphorylation of FMF-associated pyrin mutants leads to inflammasome activation. The aim of this study was to assess whether quantifying UCN-01-mediated inflammasome activation could discriminate FMF patients from healthy donors (HD) and from patients with other inflammatory disorders (OID). METHODS: Real-time pyroptosis and IL-1ß secretion were monitored in response to UCN-01 in monocytes from FMF patients (n=67), HD (n=71) and OID patients (n=40). Sensitivity and specificity of the resulting diagnostic tests were determined by receiver operating characteristic curve analyses. RESULTS: Inflammasome monitoring in response to UCN-01 discriminates FMF patients from other individuals. Pyroptosis assessment leads to a fast FMF diagnosis while combining pyroptosis and IL-1ß dosage renders UCN-01-based assays highly sensitive and specific. UCN-01-triggered monocytes responses were influenced by MEFV gene dosage and MEFV mutations in a similar way as clinical phenotypes are. CONCLUSIONS: UCN-01-based inflammasome assays could be used to rapidly diagnose FMF, with high sensitivity and specificity.


Assuntos
Febre Familiar do Mediterrâneo/diagnóstico , Inflamassomos/efeitos dos fármacos , Interleucina-1beta/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Pirina/efeitos dos fármacos , Piroptose/efeitos dos fármacos , Estaurosporina/análogos & derivados , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Artrite Juvenil/diagnóstico , Síndrome de Behçet/diagnóstico , Estudos de Casos e Controles , Criança , Pré-Escolar , Síndromes Periódicas Associadas à Criopirina/diagnóstico , Febre Familiar do Mediterrâneo/genética , Febre Familiar do Mediterrâneo/imunologia , Feminino , Febre/diagnóstico , Febre de Causa Desconhecida/diagnóstico , Doenças Hereditárias Autoinflamatórias/diagnóstico , Humanos , Testes Imunológicos/métodos , Inflamassomos/imunologia , Inflamassomos/metabolismo , Interleucina-1beta/imunologia , Interleucina-1beta/metabolismo , Lúpus Eritematoso Sistêmico/diagnóstico , Masculino , Deficiência de Mevalonato Quinase/diagnóstico , Pessoa de Meia-Idade , Monócitos/imunologia , Monócitos/metabolismo , Pirina/genética , Pirina/imunologia , Pirina/metabolismo , Sensibilidade e Especificidade , Sepse/diagnóstico , Estaurosporina/farmacologia , Doença de Still de Início Tardio/diagnóstico , Adulto Jovem
9.
Front Cell Infect Microbiol ; 10: 594063, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33363054

RESUMO

Francisella tularensis is a Select Agent that causes the severe disease tularemia in humans and many animal species. The bacterium demonstrates rapid intracellular replication, however, macrophages can control its replication if primed and activation with IFN-γ is known to be essential, although alone not sufficient, to mediate such control. To further investigate the mechanisms that control intracellular F. tularensis replication, an in vitro co-culture system was utilized containing splenocytes obtained from naïve or immunized C57BL/6 mice as effectors and infected bone marrow-derived wild-type or chromosome-3-deficient guanylate-binding protein (GBP)-deficient macrophages. Cells were infected either with the F. tularensis live vaccine strain (LVS), the highly virulent SCHU S4 strain, or the surrogate for F. tularensis, F. novicida. Regardless of strain, significant control of the bacterial replication was observed in co-cultures with wild-type macrophages and immune splenocytes, but not in cultures with immune splenocytes and GBPchr3-deficient macrophages. Supernatants demonstrated very distinct, infectious agent-dependent patterns of 23 cytokines, whereas the cytokine patterns were only marginally affected by the presence or absence of GBPs. Levels of a majority of cytokines were inversely correlated to the degree of control of the SCHU S4 and LVS infections, but this was not the case for the F. novicida infection. Collectively, the co-culture assay based on immune mouse-derived splenocytes identified a dominant role of GBPs for the control of intracellular replication of various F. tularensis strains, regardless of their virulence, whereas the cytokine patterns markedly were dependent on the infectious agents, but less so on GBPs.


Assuntos
Francisella tularensis , Tularemia , Animais , Vacinas Bacterianas , Proteínas de Transporte , Técnicas de Cocultura , Modelos Animais de Doenças , Proteínas de Ligação ao GTP , Camundongos , Camundongos Endogâmicos C57BL
10.
Can J Cardiol ; 35(10): 1419.e5-1419.e7, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601416

RESUMO

Atresia of the main stem of the left coronary artery is the least observed congenital coronary anomaly; most patients tend to receive a coronary artery bypass graft, although some anatomical corrections have been described. A 17-year-old female patient with left coronary artery main stem atresia underwent a coronary trunk construction with an autologous pericardial patch in our department. At a 3-year follow-up, the patient was asymptomatic, with a normal cardiac stress test. The coronary computed tomography showed no stenosis between the aorta and coronary bifurcation. Long-term patency has yet to be determined.


Assuntos
Anomalias dos Vasos Coronários/cirurgia , Adolescente , Feminino , Humanos , Procedimentos Cirúrgicos Vasculares/métodos
11.
EMBO Mol Med ; 11(11): e10547, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31589380

RESUMO

Familial Mediterranean fever (FMF) is the most frequent hereditary systemic autoinflammatory syndrome. FMF is usually caused by biallelic mutations in the MEFV gene, encoding Pyrin. Conclusive genetic evidence lacks for about 30% of patients diagnosed with clinical FMF. Pyrin is an inflammasome sensor maintained inactive by two kinases (PKN1/2). The consequences of MEFV mutations on inflammasome activation are still poorly understood. Here, we demonstrate that PKC superfamily inhibitors trigger inflammasome activation in monocytes from FMF patients while they trigger a delayed apoptosis in monocytes from healthy donors. The expression of the pathogenic p.M694V MEFV allele is necessary and sufficient for PKC inhibitors (or mutations precluding Pyrin phosphorylation) to trigger caspase-1- and gasdermin D-mediated pyroptosis. In line with colchicine efficacy in patients, colchicine fully blocks this response in FMF patients' monocytes. These results indicate that Pyrin inflammasome activation is solely controlled by Pyrin (de)phosphorylation in FMF patients while a second control mechanism restricts its activation in healthy donors/non-FMF patients. This study paves the way toward a functional characterization of MEFV variants and a functional test to diagnose FMF.


Assuntos
Febre Familiar do Mediterrâneo/fisiopatologia , Inflamassomos/metabolismo , Processamento de Proteína Pós-Traducional , Pirina/metabolismo , Células Cultivadas , Humanos , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Fosforilação , Inibidores de Proteínas Quinases/metabolismo , Piroptose
12.
EMBO Rep ; 20(9): e48235, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31353801

RESUMO

Caspase-4, the cytosolic LPS sensor, and gasdermin D, its downstream effector, constitute the non-canonical inflammasome, which drives inflammatory responses during Gram-negative bacterial infections. It remains unclear whether other proteins regulate cytosolic LPS sensing, particularly in human cells. Here, we conduct a genome-wide CRISPR/Cas9 screen in a human monocyte cell line to identify genes controlling cytosolic LPS-mediated pyroptosis. We find that the transcription factor, IRF2, is required for pyroptosis following cytosolic LPS delivery and functions by directly regulating caspase-4 levels in human monocytes and iPSC-derived monocytes. CASP4, GSDMD, and IRF2 are the only genes identified with high significance in this screen highlighting the simplicity of the non-canonical inflammasome. Upon IFN-γ priming, IRF1 induction compensates IRF2 deficiency, leading to robust caspase-4 expression. Deficiency in IRF2 results in dampened inflammasome responses upon infection with Gram-negative bacteria. This study emphasizes the central role of IRF family members as specific regulators of the non-canonical inflammasome.


Assuntos
Caspases Iniciadoras/metabolismo , Fator Regulador 2 de Interferon/metabolismo , Caspases Iniciadoras/genética , Morte Celular/efeitos dos fármacos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/fisiologia , Humanos , Fator Regulador 1 de Interferon/genética , Fator Regulador 1 de Interferon/metabolismo , Fator Regulador 2 de Interferon/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lipopolissacarídeos/farmacologia , Monócitos/metabolismo , Proteínas de Ligação a Fosfato/genética , Proteínas de Ligação a Fosfato/metabolismo , Células U937
13.
Nat Microbiol ; 4(4): 701-713, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30804548

RESUMO

The innate immune system is crucial for eventual control of infections, but may also contribute to pathology. Listeria monocytogenes is an intracellular Gram-positive bacteria and a major cause of food-borne disease. However, important knowledge on the interactions between L. monocytogenes and the immune system is still missing. Here, we report that Listeria DNA is sorted into extracellular vesicles (EVs) in infected cells and delivered to bystander cells to stimulate the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway. This was also observed during infections with Francisella tularensis and Legionella pneumophila. We identify the multivesicular body protein MVB12b as a target for TANK-binding kinase 1 phosphorylation, which is essential for the sorting of DNA into EVs and stimulation of bystander cells. EVs from Listeria-infected cells inhibited T-cell proliferation, and primed T cells for apoptosis. Collectively, we describe a pathway for EV-mediated delivery of foreign DNA to bystander cells, and suggest that intracellular bacteria exploit this pathway to impair antibacterial defence.


Assuntos
Vesículas Extracelulares/microbiologia , Listeria monocytogenes/fisiologia , Listeriose/metabolismo , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Vesículas Extracelulares/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Listeria monocytogenes/genética , Listeriose/genética , Listeriose/microbiologia , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Nucleotídeos Cíclicos , Nucleotidiltransferases/genética , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas de Transporte Vesicular/genética
14.
Nat Microbiol ; 3(10): 1187, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30177744

RESUMO

In the version of this Article originally published, the name of author Robert Jan Lebbink was coded wrongly, resulting in it being incorrect when exported to citation databases. This has now been corrected, though no visible changes will be apparent.

15.
Oncotarget ; 9(47): 28364-28378, 2018 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-29983866

RESUMO

Neutrophils are known to possess both pro- and anti-tumor properties, a feature that could be related to the diversity and plasticity of these cells. Here we explored the hypothesis that under an appropriate environment and stimuli, neutrophils could induce an effective response against tumor cells. In a rat and mouse models, we show that a substantial amount of colon tumor associated-neutrophils (TAN) expressed the cytolytic enzyme granzyme B, which is absent in spleen or blood circulating neutrophils. This TAN population was also found into tumors of patients with colon cancer. Tumor neutrophil infiltration was correlated with an increase of chemokines known to attract neutrophils in both rat models and patients. These cells were involved in a Lipid A analog-mediated colon tumor regression. Mechanistically, treating the rats with the Lipid A analog triggered granzyme B release from neutrophils in tumor cell vicinity, which was correlated to tumor regression. Alteration of granzyme B function in tumor cells decreased the cytotoxic effect of Lipid A in rat and mouse models. Granzyme B expression in neutrophils could be induced by the lipid A analog but also by some of the cytokines that were detected in the tumor microenvironment. These results identify a subpopulation of neutrophils expressing granzyme B that can act as a key player of lipid A-mediated colon cancer regression in rat and mouse models and the molecular mechanisms involved may provide novel approaches for human therapeutic intervention.

16.
Nat Microbiol ; 3(6): 708-717, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29736038

RESUMO

The staphylococcal bi-component leukocidins Panton-Valentine leukocidin (PVL) and γ-haemolysin CB (HlgCB) target human phagocytes. Binding of the toxins' S-components to human complement C5a receptor 1 (C5aR1) contributes to cellular tropism and human specificity of PVL and HlgCB. To investigate the role of both leukocidins during infection, we developed a human C5aR1 knock-in (hC5aR1KI) mouse model. HlgCB, but unexpectedly not PVL, contributed to increased bacterial loads in tissues of hC5aR1KI mice. Compared to humans, murine hC5aR1KI neutrophils showed a reduced sensitivity to PVL, which was mediated by the toxin's F-component LukF-PV. By performing a genome-wide CRISPR-Cas9 screen, we identified CD45 as a receptor for LukF-PV. The human-specific interaction between LukF-PV and CD45 provides a molecular explanation for resistance of hC5aR1KI mouse neutrophils to PVL and probably contributes to the lack of a PVL-mediated phenotype during infection in these mice. This study demonstrates an unsuspected role of the F-component in driving the sensitivity of human phagocytes to PVL.


Assuntos
Toxinas Bacterianas/metabolismo , Exotoxinas/metabolismo , Leucocidinas/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Receptor da Anafilatoxina C5a/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/patogenicidade , Animais , Carga Bacteriana , Proteínas de Bactérias/metabolismo , Sistemas CRISPR-Cas , Linhagem Celular , Modelos Animais de Doenças , Proteínas Hemolisinas/metabolismo , Humanos , Camundongos , Camundongos Knockout , Neutrófilos/metabolismo , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/metabolismo
17.
Nat Commun ; 9(1): 242, 2018 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-29339744

RESUMO

Caspase-4/5 in humans and caspase-11 in mice bind hexa-acylated lipid A, the lipid moeity of lipopolysaccharide (LPS), to induce the activation of non-canonical inflammasome. Pathogens such as Francisella novicida express an under-acylated lipid A and escape caspase-11 recognition in mice. Here, we show that caspase-4 drives inflammasome responses to F. novicida infection in human macrophages. Caspase-4 triggers F. novicida-mediated, gasdermin D-dependent pyroptosis and activates the NLRP3 inflammasome. Inflammasome activation could be recapitulated by transfection of under-acylated LPS from different bacterial species or synthetic tetra-acylated lipid A into cytosol of human macrophage. Our results indicate functional differences between human caspase-4 and murine caspase-11. We further establish that human Guanylate-binding proteins promote inflammasome responses to under-acylated LPS. Altogether, our data demonstrate a broader reactivity of caspase-4 to under-acylated LPS than caspase-11, which may have important clinical implications for management of sepsis.


Assuntos
Caspases Iniciadoras/metabolismo , Caspases/metabolismo , Francisella/metabolismo , Lipopolissacarídeos/metabolismo , Macrófagos/metabolismo , Acilação , Animais , Caspases/genética , Caspases Iniciadoras/genética , Células Cultivadas , Citosol/microbiologia , Francisella/fisiologia , Humanos , Inflamassomos/genética , Inflamassomos/metabolismo , Macrófagos/microbiologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Interferência de RNA , Especificidade da Espécie , Células U937
18.
Rheumatology (Oxford) ; 57(1): 100-111, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29040788

RESUMO

Objectives: FMF is the most frequent autoinflammatory disease and is associated in most patients with bi-allelic MEFV mutations. MEFV encodes Pyrin, an inflammasome sensor activated following RhoGTPase inhibition. The functional consequences of MEFV mutations on the ability of Pyrin variants to act as inflammasome sensors are largely unknown. The aim of this study was to assess whether MEFV mutations affect the ability of Pyrin to detect RhoGTPase inhibition and other inflammasome stimuli. Methods: IL-1ß and IL-18 released by monocytes from healthy donors (HDs) and FMF patients were measured upon specific engagement of the Pyrin, NLRP3 and NLRC4 inflammasomes. Cell death kinetics following Pyrin activation was monitored in real time. Results: Monocytes from FMF patients secreted significantly more IL-1ß and IL-18 and died significantly faster than HD monocytes in response to low concentrations of Clostridium difficile toxin B (TcdB), a Pyrin-activating stimulus. Monocytes from patients bearing two MEFV exon 10 pathogenic variants displayed an increased Pyrin inflammasome response compared with monocytes from patients with a single exon 10 pathogenic variant indicating a gene-dosage effect. Using a short priming step, the response of monocytes from FMF patients to NLRP3- and NLRC4-activating stimuli was normal indicating that MEFV mutations trigger a specific hypersensitivity of monocytes to low doses of a Pyrin-engaging stimulus. Conclusion: Contrary to the NLRP3 mutations described in cryopyrin-associated periodic syndrome, FMF-associated MEFV mutations do not lead to a constitutive activation of Pyrin. Rather, FMF-associated mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome without affecting other canonical inflammasomes.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/imunologia , Proteínas de Ligação ao Cálcio/imunologia , Febre Familiar do Mediterrâneo/genética , Monócitos/imunologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Pirina/genética , Trifosfato de Adenosina/farmacologia , Adolescente , Adulto , Antígenos de Bactérias/farmacologia , Proteínas de Bactérias/farmacologia , Toxinas Bacterianas/farmacologia , Estudos de Casos e Controles , Morte Celular , Criança , Pré-Escolar , Febre Familiar do Mediterrâneo/imunologia , Feminino , Voluntários Saudáveis , Humanos , Inflamassomos/genética , Interleucina-18/imunologia , Interleucina-1beta/imunologia , Ionóforos/farmacologia , Masculino , Pessoa de Meia-Idade , Monócitos/efeitos dos fármacos , Mutação , Nigericina/farmacologia , Pirina/imunologia , Salmonella typhimurium , Proteínas rho de Ligação ao GTP
19.
PLoS Pathog ; 13(10): e1006630, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28968459

RESUMO

Guanylate binding proteins (GBPs) are interferon-inducible proteins involved in the cell-intrinsic immunity against numerous intracellular pathogens. The molecular mechanisms underlying the potent antibacterial activity of GBPs are still unclear. GBPs have been functionally linked to the NLRP3, the AIM2 and the caspase-11 inflammasomes. Two opposing models are currently proposed to explain the GBPs-inflammasome link: i) GBPs would target intracellular bacteria or bacteria-containing vacuoles to increase cytosolic PAMPs release ii) GBPs would directly facilitate inflammasome complex assembly. Using Francisella novicida infection, we investigated the functional interactions between GBPs and the inflammasome. GBPs, induced in a type I IFN-dependent manner, are required for the F. novicida-mediated AIM2-inflammasome pathway. Here, we demonstrate that GBPs action is not restricted to the AIM2 inflammasome, but controls in a hierarchical manner the activation of different inflammasomes complexes and apoptotic caspases. IFN-γ induces a quantitative switch in GBPs levels and redirects pyroptotic and apoptotic pathways under the control of GBPs. Furthermore, upon IFN-γ priming, F. novicida-infected macrophages restrict cytosolic bacterial replication in a GBP-dependent and inflammasome-independent manner. Finally, in a mouse model of tularemia, we demonstrate that the inflammasome and the GBPs are two key immune pathways functioning largely independently to control F. novicida infection. Altogether, our results indicate that GBPs are the master effectors of IFN-γ-mediated responses against F. novicida to control antibacterial immune responses in inflammasome-dependent and independent manners.


Assuntos
Francisella tularensis/imunologia , Proteínas de Ligação ao GTP/imunologia , Inflamassomos/imunologia , Interferon gama/imunologia , Tularemia/imunologia , Animais , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunofluorescência , Francisella , Técnicas de Silenciamento de Genes , Infecções por Bactérias Gram-Negativas/imunologia , Immunoblotting , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
20.
Interact Cardiovasc Thorac Surg ; 24(6): 898-904, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28329066

RESUMO

OBJECTIVES: The use of marginal donors with cardiovascular risk factors is increasing due to organ shortage but remains controversial in heart transplantation (HTx). We sought to investigate post-transplant outcomes in the recent era taking into account donor characteristics. METHODS: We reviewed 261 HTx performed in our hospital between January 1996 and March 2013. Donor characteristics were obtained from the national database. The incidence of primary graft dysfunction (PGD) and cardiac allograft vasculopathy (CAV) and overall survival were compared in 2 groups of HTx recipients: those receiving transplants from 1996 to 2004 (Group A, n = 120) and from 2005 to 2013 (Group B, n = 141). RESULTS: The mean age of the donors was 34 ± 12 years in Group A vs 42 ± 13 years in Group B ( P < 0.001). Donors in Group B had a higher body mass index (23 ± 2 vs 26 ± 5 kg/m 2 , P < 0.001), were more likely to be smokers (29.6% vs 52.9%, P < 0.001) and were more likely to have hypertension (5% vs 13.5%, P = 0.030). There was no difference in survival at 1 and 5 years (79% and 63% in Group A vs 80% and 62% in Group B, respectively; P = 0.551). The rate of PGD was 36% in Group A vs 40% in Group B ( P = 0.092). Freedom from CAV at 5 years was 64% and 61%, respectively ( P = 0.367). Among the characteristics of the donors, only hypertension was associated with reduced survival. CONCLUSIONS: The use of older cardiac donors with more cardiovascular comorbidities in the recent era did not impair the post-transplant outcomes. Donor hypertension was the only determinant of worse survival.


Assuntos
Doenças Cardiovasculares/cirurgia , Transplante de Coração , Disfunção Primária do Enxerto/epidemiologia , Doadores de Tecidos , Adulto , Doenças Cardiovasculares/epidemiologia , Comorbidade , Feminino , França/epidemiologia , Sobrevivência de Enxerto , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
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