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1.
Foods ; 13(14)2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39063317

ABSTRACT

Color is one of the first criteria to assess the quality of cheese. However, very limited data are available on the color heterogeneity of the rind and its relationship with microbial community structure. In this study, the color of a wide range of smear-ripened Munster cheeses from various origins was monitored during storage by photographic imaging and data analysis in the CIELAB color space using luminance, chroma, and hue angle as descriptors. Different levels of inter- and intra-cheese heterogeneity were observed. The most heterogeneous Munster cheeses were the darkest with orange-red colors. The most homogeneous were the brightest with yellow-orange. K-means clustering revealed three clusters distinguished by their color heterogeneity. Color analysis coupled with metabarcoding showed that rinds with heterogeneous color exhibited higher microbial diversity associated with important changes in their microbial community structure during storage. In addition, intra-cheese community structure fluctuations were associated with heterogeneity in rind color. The species Glutamicibacter arilaitensis and Psychrobacter nivimaris/piscatorii were found to be positively associated with the presence of undesirable brown patches. This study highlights the close relationship between the heterogeneity of the cheese rind and its microbiota.

2.
J Clin Med ; 13(9)2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38731130

ABSTRACT

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.

3.
Cell Death Dis ; 14(3): 213, 2023 03 25.
Article in English | MEDLINE | ID: mdl-36966139

ABSTRACT

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.


Subject(s)
Familial Mediterranean Fever , Inflammasomes , Pyrin , Humans , Familial Mediterranean Fever/genetics , Familial Mediterranean Fever/metabolism , Inflammasomes/genetics , Inflammasomes/metabolism , Mutation , Pyrin/genetics , Pyrin/metabolism
4.
Cell Rep ; 41(2): 111472, 2022 10 11.
Article in English | MEDLINE | ID: mdl-36223753

ABSTRACT

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.


Subject(s)
Familial Mediterranean Fever , Inflammasomes , Pyrin , Etiocholanolone , Familial Mediterranean Fever/genetics , Familial Mediterranean Fever/metabolism , Humans , Inflammasomes/metabolism , Mutation , Pregnanolone , Progesterone , Pyrin/genetics , Pyrin/metabolism , Testosterone
5.
JACC Case Rep ; 3(12): 1453-1455, 2021 Sep 15.
Article in English | MEDLINE | ID: mdl-34557691

ABSTRACT

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.).

6.
Arch Cardiovasc Dis ; 114(5): 364-370, 2021 May.
Article in English | MEDLINE | ID: mdl-33541832

ABSTRACT

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.


Subject(s)
COVID-19/epidemiology , Cardiac Surgical Procedures , Hospitals, High-Volume/statistics & numerical data , Pandemics , Quarantine , SARS-CoV-2 , Aged , Bed Conversion/statistics & numerical data , Cardiac Surgical Procedures/mortality , Cardiac Surgical Procedures/statistics & numerical data , Comorbidity , Cross Infection/epidemiology , Diagnosis-Related Groups , Elective Surgical Procedures/mortality , Elective Surgical Procedures/statistics & numerical data , Female , France/epidemiology , Heart Diseases/epidemiology , Heart Diseases/surgery , Hospitals, University/statistics & numerical data , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Postoperative Complications/epidemiology , Procedures and Techniques Utilization , Prospective Studies , Recovery Room/statistics & numerical data , Time-to-Treatment , Waiting Lists
7.
Emerg Microbes Infect ; 10(1): 277-290, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33538648

ABSTRACT

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.


Subject(s)
Amoeba/microbiology , Francisella tularensis/growth & development , Fresh Water/microbiology , Microbial Viability
8.
Front Cell Infect Microbiol ; 11: 784101, 2021.
Article in English | MEDLINE | ID: mdl-35004352

ABSTRACT

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.


Subject(s)
Francisella tularensis , Macrophages/immunology , Tularemia , Animals , Bacterial Vaccines , Carrier Proteins , Cells, Cultured , Humans , Mice , Tularemia/immunology , Virulence
9.
Ann Rheum Dis ; 80(1): 128-132, 2021 01.
Article in English | MEDLINE | ID: mdl-33037005

ABSTRACT

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.


Subject(s)
Familial Mediterranean Fever/diagnosis , Inflammasomes/drug effects , Interleukin-1beta/drug effects , Monocytes/drug effects , Protein Kinase Inhibitors/pharmacology , Pyrin/drug effects , Pyroptosis/drug effects , Staurosporine/analogs & derivatives , Adolescent , Adult , Aged , Aged, 80 and over , Arthritis, Juvenile/diagnosis , Behcet Syndrome/diagnosis , Case-Control Studies , Child , Child, Preschool , Cryopyrin-Associated Periodic Syndromes/diagnosis , Familial Mediterranean Fever/genetics , Familial Mediterranean Fever/immunology , Female , Fever/diagnosis , Fever of Unknown Origin/diagnosis , Hereditary Autoinflammatory Diseases/diagnosis , Humans , Immunologic Tests/methods , Inflammasomes/immunology , Inflammasomes/metabolism , Interleukin-1beta/immunology , Interleukin-1beta/metabolism , Lupus Erythematosus, Systemic/diagnosis , Male , Mevalonate Kinase Deficiency/diagnosis , Middle Aged , Monocytes/immunology , Monocytes/metabolism , Pyrin/genetics , Pyrin/immunology , Pyrin/metabolism , Sensitivity and Specificity , Sepsis/diagnosis , Staurosporine/pharmacology , Still's Disease, Adult-Onset/diagnosis , Young Adult
10.
Front Cell Infect Microbiol ; 10: 594063, 2020.
Article in English | MEDLINE | ID: mdl-33363054

ABSTRACT

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.


Subject(s)
Francisella tularensis , Tularemia , Animals , Bacterial Vaccines , Carrier Proteins , Coculture Techniques , Disease Models, Animal , GTP-Binding Proteins , Mice , Mice, Inbred C57BL
11.
EMBO Mol Med ; 11(11): e10547, 2019 11 07.
Article in English | MEDLINE | ID: mdl-31589380

ABSTRACT

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.


Subject(s)
Familial Mediterranean Fever/physiopathology , Inflammasomes/metabolism , Protein Processing, Post-Translational , Pyrin/metabolism , Cells, Cultured , Humans , Monocytes/drug effects , Monocytes/metabolism , Phosphorylation , Protein Kinase Inhibitors/metabolism , Pyroptosis
12.
Can J Cardiol ; 35(10): 1419.e5-1419.e7, 2019 10.
Article in English | MEDLINE | ID: mdl-31601416

ABSTRACT

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.


Subject(s)
Coronary Vessel Anomalies/surgery , Adolescent , Female , Humans , Vascular Surgical Procedures/methods
13.
EMBO Rep ; 20(9): e48235, 2019 09.
Article in English | MEDLINE | ID: mdl-31353801

ABSTRACT

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.


Subject(s)
Caspases, Initiator/metabolism , Interferon Regulatory Factor-2/metabolism , Caspases, Initiator/genetics , Cell Death/drug effects , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/physiology , Humans , Interferon Regulatory Factor-1/genetics , Interferon Regulatory Factor-1/metabolism , Interferon Regulatory Factor-2/genetics , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lipopolysaccharides/pharmacology , Monocytes/metabolism , Phosphate-Binding Proteins/genetics , Phosphate-Binding Proteins/metabolism , U937 Cells
14.
Nat Microbiol ; 4(4): 701-713, 2019 04.
Article in English | MEDLINE | ID: mdl-30804548

ABSTRACT

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.


Subject(s)
Extracellular Vesicles/microbiology , Listeria monocytogenes/physiology , Listeriosis/metabolism , Membrane Proteins/metabolism , Nucleotidyltransferases/metabolism , Protein Serine-Threonine Kinases/metabolism , Vesicular Transport Proteins/metabolism , Animals , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Extracellular Vesicles/metabolism , Host-Pathogen Interactions , Humans , Listeria monocytogenes/genetics , Listeriosis/genetics , Listeriosis/microbiology , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Nucleotides, Cyclic , Nucleotidyltransferases/genetics , Phosphorylation , Protein Serine-Threonine Kinases/genetics , Vesicular Transport Proteins/genetics
15.
Nat Microbiol ; 3(10): 1187, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30177744

ABSTRACT

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.

16.
Oncotarget ; 9(47): 28364-28378, 2018 Jun 19.
Article in English | MEDLINE | ID: mdl-29983866

ABSTRACT

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.

17.
Nat Microbiol ; 3(6): 708-717, 2018 06.
Article in English | MEDLINE | ID: mdl-29736038

ABSTRACT

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.


Subject(s)
Bacterial Toxins/metabolism , Exotoxins/metabolism , Leukocidins/metabolism , Leukocyte Common Antigens/metabolism , Receptor, Anaphylatoxin C5a/genetics , Staphylococcal Infections/microbiology , Staphylococcus aureus/pathogenicity , Animals , Bacterial Load , Bacterial Proteins/metabolism , CRISPR-Cas Systems , Cell Line , Disease Models, Animal , Hemolysin Proteins/metabolism , Humans , Mice , Mice, Knockout , Neutrophils/metabolism , Staphylococcal Infections/genetics , Staphylococcal Infections/immunology , Staphylococcal Infections/metabolism , Staphylococcus aureus/metabolism
18.
Nat Commun ; 9(1): 242, 2018 01 16.
Article in English | MEDLINE | ID: mdl-29339744

ABSTRACT

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.


Subject(s)
Caspases, Initiator/metabolism , Caspases/metabolism , Francisella/metabolism , Lipopolysaccharides/metabolism , Macrophages/metabolism , Acylation , Animals , Caspases/genetics , Caspases, Initiator/genetics , Cells, Cultured , Cytosol/microbiology , Francisella/physiology , Humans , Inflammasomes/genetics , Inflammasomes/metabolism , Macrophages/microbiology , Mice, Inbred C57BL , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , RNA Interference , Species Specificity , U937 Cells
19.
Rheumatology (Oxford) ; 57(1): 100-111, 2018 01 01.
Article in English | MEDLINE | ID: mdl-29040788

ABSTRACT

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.


Subject(s)
CARD Signaling Adaptor Proteins/immunology , Calcium-Binding Proteins/immunology , Familial Mediterranean Fever/genetics , Monocytes/immunology , NLR Family, Pyrin Domain-Containing 3 Protein/immunology , Pyrin/genetics , Adenosine Triphosphate/pharmacology , Adolescent , Adult , Antigens, Bacterial/pharmacology , Bacterial Proteins/pharmacology , Bacterial Toxins/pharmacology , Case-Control Studies , Cell Death , Child , Child, Preschool , Familial Mediterranean Fever/immunology , Female , Healthy Volunteers , Humans , Inflammasomes/genetics , Interleukin-18/immunology , Interleukin-1beta/immunology , Ionophores/pharmacology , Male , Middle Aged , Monocytes/drug effects , Mutation , Nigericin/pharmacology , Pyrin/immunology , Salmonella typhimurium , rho GTP-Binding Proteins
20.
PLoS Pathog ; 13(10): e1006630, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28968459

ABSTRACT

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.


Subject(s)
Francisella tularensis/immunology , GTP-Binding Proteins/immunology , Inflammasomes/immunology , Interferon-gamma/immunology , Tularemia/immunology , Animals , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Fluorescent Antibody Technique , Francisella , Gene Knockdown Techniques , Gram-Negative Bacterial Infections/immunology , Immunoblotting , Male , Mice , Mice, Inbred C57BL , Mice, Knockout
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