Two parallel pathways connect glutamine metabolism and mTORC1 activity to regulate glutamoptosis.

Glutamoptosis is the induction of apoptotic cell death as a consequence of the aberrant activation of glutaminolysis and mTORC1 signaling during nutritional imbalance in proliferating cells. The role of the bioenergetic sensor AMPK during glutamoptosis is not defined yet. Here, we show that AMPK reactivation blocks both the glutamine-dependent activation of mTORC1 and glutamoptosis in vitro and in vivo. We also show that glutamine is used for asparagine synthesis and the GABA shunt to produce ATP and to inhibit AMPK, independently of glutaminolysis. Overall, our results indicate that glutamine metabolism is connected with mTORC1 activation through two parallel pathways: an acute alpha-ketoglutarate-dependent pathway; and a secondary ATP/AMPK-dependent pathway. This dual metabolic connection between glutamine and mTORC1 must be considered for the future design of therapeutic strategies to prevent cell growth in diseases such as cancer.This work was supported by funds from the following institutions: Agencia Estatal de Investigación/European Regional Development Fund, European Union (PGC2018-096244- B-I00, SAF2016-75442-R), Ministry of Science, Innovation and Universities of Spain, Spanish National Research Council—CSIC, Institut National de la Santé et de la Recherche Médicale —INSERM, Université de Bordeaux, Fondation pour la Recherche Médicale, the Conseil Régional d’Aquitaine, SIRIC-BRIO, Fondation ARC, and Institut Européen de Chimie et Biologie. C.B. was recipient of fellowships from the Minister of Higher Education, Research and Innovation (France) and the Fondation ARC (France). We thank Prof. Patricia Boya (Centro de Investigaciones Biologicas, Madrid, Spain) for kindly providing with the ATG5+/+ and ATG5−/− MEFs. We thank Prof. Benoit Viollet (Institute Cochin, Paris, France) for kindly providing with the AMPK+/+ and AMPK−/− MEFs, and the CA-AMPK plasmid

Erratum to: Methods for evaluating medical tests and biomarkers

[This corrects the article DOI: 10.1186/s41512-016-0001-y.]

Erratum to: Methods for evaluating medical tests and biomarkers

[This corrects the article DOI: 10.1186/s41512-016-0001-y.]

Evidence synthesis to inform model-based cost-effectiveness evaluations of diagnostic tests: a methodological systematic review of health technology assessments

Background: Evaluations of diagnostic tests are challenging because of the indirect nature of their impact on patient outcomes. Model-based health economic evaluations of tests allow different types of evidence from various sources to be incorporated and enable cost-effectiveness estimates to be made beyond the duration of available study data. To parameterize a health-economic model fully, all the ways a test impacts on patient health must be quantified, including but not limited to diagnostic test accuracy. Methods: We assessed all UK NIHR HTA reports published May 2009-July 2015. Reports were included if they evaluated a diagnostic test, included a model-based health economic evaluation and included a systematic review and meta-analysis of test accuracy. From each eligible report we extracted information on the following topics: 1) what evidence aside from test accuracy was searched for and synthesised, 2) which methods were used to synthesise test accuracy evidence and how did the results inform the economic model, 3) how/whether threshold effects were explored, 4) how the potential dependency between multiple tests in a pathway was accounted for, and 5) for evaluations of tests targeted at the primary care setting, how evidence from differing healthcare settings was incorporated. Results: The bivariate or HSROC model was implemented in 20/22 reports that met all inclusion criteria. Test accuracy data for health economic modelling was obtained from meta-analyses completely in four reports, partially in fourteen reports and not at all in four reports. Only 2/7 reports that used a quantitative test gave clear threshold recommendations. All 22 reports explored the effect of uncertainty in accuracy parameters but most of those that used multiple tests did not allow for dependence between test results. 7/22 tests were potentially suitable for primary care but the majority found limited evidence on test accuracy in primary care settings. Conclusions: The uptake of appropriate meta-analysis methods for synthesising evidence on diagnostic test accuracy in UK NIHR HTAs has improved in recent years. Future research should focus on other evidence requirements for cost-effectiveness assessment, threshold effects for quantitative tests and the impact of multiple diagnostic tests

Study of gastric carcinogenesis induced by helicobacter pylori and implicating the epithelial to mesenchymal transition

L’infection par Helicobacter pylori touche environ la moitié de la population mondiale et est responsable de plusieurs pathologies gastro-intestinales incluant l’adénocarcinome gastrique. Les mécanismes de la carcinogénèse induite par H. pylori ne sont pas clairement élucidés. Mais, l’oncoprotéine CagA que possèdent certaines souches est très impliquée dans la carcinogénèse gastrique ; elle induit l’apparition d’un phénotype particulier, dit colibri, qui mime une transition épithélio-mésenchymateuse (EMT). De plus, CagA déstabilise les jonctions cellulaires en perturbant la E-cadhérine. Les objectifs de ces travaux ont été de déterminer si H. pylori induit une véritable EMT et si cette EMT est à l’origine de l’émergence de cellules souches cancéreuses (CSC). De plus, nous avons étudié le rôle joué par la protéine IQGAP1, protéine assurant le maintien des jonctions cellulaires, dans la carcinogénèse gastrique induite par H. pylori. Ces travaux ont montré que H. pylori induit une EMT in vitro. Cette EMT est à l’origine de l’émergence de cellules CD44high présentant les caractéristiques de CSC. L’étude du rôle de IQGAP1 au cours de la carcinogénèse gastrique liée à H. pylori a permis de déterminer son implication dans l’apparition de lésions néoplasiques dans un modèle de souris transgéniques hétérozygotes pour IQGAP1. En outre, IQGAP1 apparaît comme une protéine dont l’expression est modifiée par l’infection à H. pylori et par l’EMT induite par cette bactérie in vitro. Nos résultats permettent de mieux comprendre le mécanisme physiopathologique de l’adénocarcinome gastrique et seront potentiellement utiles au développement de nouvelles thérapeutiques anti-cancéreuses.Helicobacter pylori infection is found in about half of the world population and is responsible for several gastrointestinal pathologies, including gastric adenocarcinoma. The mechanisms of the carcinogenesis due to H. pylori remain unclear. However, the link with gastric adenocarcinoma is partly due to the H. pylori CagA oncoprotein. CagA is responsible for a particular cell phenotype in vitro, the “hummingbird” phenotype which corresponds to an elongation of the cells, mimicking an epithelial to mesenchymal transition (EMT). EMT participates to carcinogenesis, and is involved in the generation of cancer stem cells (CSC). Moreover, CagA destabilize the cell junctions. This study aimed to determine wether H. pylori induces a true EMT, and if so, wether this EMT can generate CSCs. The role of IQGAP1, which is a scaffold protein involved in cell adhesion, was also studied in cases of gastric carcinogenesis due to H. pylori. We demonstrated that H. pylori induces an EMT in vitro. Moreover, we showed that this EMT is responsible for the emergence of CD44high cells which have the same characteristics as the CSCs. IQGAP1 has been identified as a protein implicated in neoplastic lesion development in a transgenic mouse model heterozygous for IQGAP1. Moreover, in vitro, the expression of IQGAP1 was modified by H. pylori infection and more specifically by the EMT induced by H. pylori. Our results allow a better understanding of gastric adenocarcinoma pathophysiology and will be helpful in developing new cancer chemotherapies

Study of gastric carcinogenesis induced by helicobacter pylori and implicating the epithelial to mesenchymal transition

L’infection par Helicobacter pylori touche environ la moitié de la population mondiale et est responsable de plusieurs pathologies gastro-intestinales incluant l’adénocarcinome gastrique. Les mécanismes de la carcinogénèse induite par H. pylori ne sont pas clairement élucidés. Mais, l’oncoprotéine CagA que possèdent certaines souches est très impliquée dans la carcinogénèse gastrique ; elle induit l’apparition d’un phénotype particulier, dit colibri, qui mime une transition épithélio-mésenchymateuse (EMT). De plus, CagA déstabilise les jonctions cellulaires en perturbant la E-cadhérine. Les objectifs de ces travaux ont été de déterminer si H. pylori induit une véritable EMT et si cette EMT est à l’origine de l’émergence de cellules souches cancéreuses (CSC). De plus, nous avons étudié le rôle joué par la protéine IQGAP1, protéine assurant le maintien des jonctions cellulaires, dans la carcinogénèse gastrique induite par H. pylori. Ces travaux ont montré que H. pylori induit une EMT in vitro. Cette EMT est à l’origine de l’émergence de cellules CD44high présentant les caractéristiques de CSC. L’étude du rôle de IQGAP1 au cours de la carcinogénèse gastrique liée à H. pylori a permis de déterminer son implication dans l’apparition de lésions néoplasiques dans un modèle de souris transgéniques hétérozygotes pour IQGAP1. En outre, IQGAP1 apparaît comme une protéine dont l’expression est modifiée par l’infection à H. pylori et par l’EMT induite par cette bactérie in vitro. Nos résultats permettent de mieux comprendre le mécanisme physiopathologique de l’adénocarcinome gastrique et seront potentiellement utiles au développement de nouvelles thérapeutiques anti-cancéreuses.Helicobacter pylori infection is found in about half of the world population and is responsible for several gastrointestinal pathologies, including gastric adenocarcinoma. The mechanisms of the carcinogenesis due to H. pylori remain unclear. However, the link with gastric adenocarcinoma is partly due to the H. pylori CagA oncoprotein. CagA is responsible for a particular cell phenotype in vitro, the “hummingbird” phenotype which corresponds to an elongation of the cells, mimicking an epithelial to mesenchymal transition (EMT). EMT participates to carcinogenesis, and is involved in the generation of cancer stem cells (CSC). Moreover, CagA destabilize the cell junctions. This study aimed to determine wether H. pylori induces a true EMT, and if so, wether this EMT can generate CSCs. The role of IQGAP1, which is a scaffold protein involved in cell adhesion, was also studied in cases of gastric carcinogenesis due to H. pylori. We demonstrated that H. pylori induces an EMT in vitro. Moreover, we showed that this EMT is responsible for the emergence of CD44high cells which have the same characteristics as the CSCs. IQGAP1 has been identified as a protein implicated in neoplastic lesion development in a transgenic mouse model heterozygous for IQGAP1. Moreover, in vitro, the expression of IQGAP1 was modified by H. pylori infection and more specifically by the EMT induced by H. pylori. Our results allow a better understanding of gastric adenocarcinoma pathophysiology and will be helpful in developing new cancer chemotherapies

Evaluation of a rapid fluorescence immunoassay for detecting Campylobacter antigens in stool samples

Abstract Background The species most frequently causing campylobacteriosis are Campylobacter jejuni and Campylobacter coli, followed by Campylobacter fetus, Campylobacter upsaliensis, and Campylobacter lari. Although polymerase chain reaction (PCR) can be used to detect Campylobacter DNA in stool samples, PCR assays are often validated for C. jejuni and C. coli only, and coproculture results can take several days to receive. For laboratories that do not have access to PCR technology, rapid antigen tests can be of the utmost importance for early diagnosis of the disease. We evaluated the performance of the Sofia Campylobacter Fluorescence Immunoassay (SCFIA) for rapid detection of Campylobacter antigens in stool. Methods: In total, 94 frozen and 205 fresh stool specimens were included in retrospective and prospective evaluations, respectively. The linearity of the assay and its limit of detection for different Campylobacter species was evaluated using serial dilutions. Cross reactivity to phylogenetically related species was also investigated. The PCR results from the BD MAX Enteric Panel were considered the gold standard. Results: The sensitivity of the SCFIA was 97.87% and 96.88% in retrospective and prospective evaluations, respectively. The specificity was 98.84%. The assay exhibited high linearity in serial dilutions for C. coli, C. jejuni, C. armoricus, C. ornithocola, C. lari, and C. upsaliensis, with correlation coefficients of 0.991–0.999, whereas C. fetus was not detected. No cross-reactivity was detected for Aliarcobacter butzleri, Helicobacter cinaedi, or Helicobacter pullorum. The minimum concentration for a positive result at the assay-specific cut-off was 4–17 million CFU/mL. The limit of detection ranged from 106 to 107 CFU/mL. Conclusion: SCFIA results are highly correlated with PCR results, with no cross-reactivity with phylogenetically related species. The linear correlation between fluorescence and CFU/mL results was strong. The assay’s ability to detect antigens of various Campylobacter species can aid early diagnosis. However, the inability to detect C. fetus must be considered

J Clin Microbiol

The detection of campylobacters in stools is performed essentially by culture, but this technique has a low sensitivity. New detection methods are now available. Among them, immunochromatography tests (ICTs) are very attractive in that they offer a result within 15 min. However, previous studies suggest that these tests have a relatively low specificity. The objective of this study was to evaluate the performance of these tests. During the study period, all patients who consulted the emergency units and had a stool culture were included. Their stool samples were tested with two ICTs, Ridaquick Campylobacter and ImmunoCard STAT! Campy. Stools were also tested by a home-made PCR and two commercially available enzyme-linked immunosorbent assays (ELISAs) when one of the ICTs was positive. The composite reference standard (CRS) was defined as positive if the culture was positive or, in case of a negative culture, if the PCR and one of the ELISAs were positive simultaneously. Three hundred and five patients were included. Among the 50 positive specimens with Ridaquick Campylobacter, 47 were considered true positives by the CRS, corresponding to a positive predictive value (PPV) of 94.0%. Among the 52 positive specimens with ImmunoCard STAT! Campy, 44 were considered true positives by the CRS, corresponding to a PPV of 84.6%. The negative predictive values were estimated at 94.9 and 92.4% for the Ridaquick Campylobacter and ImmunoCard STAT! Campy tests, respectively. ICTs appear to be very efficient and allow a very rapid detection of campylobacters, which is important for treating early campylobacter infections with an adapted antibiotherapy

Infect Dis Now

BACKGROUND: Central catheter-related bloodstream infections (CRBIs) can lead to severe complications, including suppurative thrombophlebitis, endocarditis, and metastatic infections. While complications due to CRBIs caused by Staphylococcus aureus (SA) are well-known, there are limited data regarding CRBIs caused by other bacteria. METHODS: This 2-year retrospective single-center study of patients with CRBIs from a tertiary care hospital examined the hematogenous complications associated with CRBIs according to patient characteristics, central venous catheter (CVC) types, and causative bacteria. RESULTS: All in all, 254 patients with confirmed CRBIs were included; 285 bacteria types were isolated, mainly Enterobacteriaceae (n = 94), coagulase-negative Staphylococci (CNS, n = 82), SA (n = 45), and non-fermenting Gram-negative bacteria (NGB, n = 45). Among the patients, 35 developed at least one hematogenous complication (14%), including suppurative thrombophlebitis (n = 15), endocarditis (n = 7) and metastatic infections (n = 16). In multivariate analysis, hemodialysis, persistent bacteremia for at least 3 days, and CRBIs caused by SA were associated with increased risk for hematogenous complications, while previous curative anticoagulant treatment was associated with reduced risk. Diabetes, CVC maintenance, and hematogenous complications were associated with increased 3-month mortality. CONCLUSION: A thorough investigation of hematogenous complications should be envisioned in patients with persistent bacteremia, particularly those with SA infections and those on hemodialysis

Two parallel pathways connect glutamine metabolism and mTORC1 activity to regulate glutamoptosis

AbstractGlutamoptosis is the induction of apoptotic cell death as a consequence of the aberrant activation of glutaminolysis and mTORC1 signaling during nutritional imbalance in proliferating cells. The role of the bioenergetic sensor AMPK during glutamoptosis is not defined yet. Here, we show that AMPK reactivation blocks both the glutamine-dependent activation of mTORC1 and glutamoptosis in vitro and in vivo. We also show that glutamine is used for asparagine synthesis and the GABA shunt to produce ATP and to inhibit AMPK, independently of glutaminolysis. Overall, our results indicate that glutamine metabolism is connected with mTORC1 activation through two parallel pathways: an acute alpha-ketoglutarate-dependent pathway; and a secondary ATP/AMPK-dependent pathway. This dual metabolic connection between glutamine and mTORC1 must be considered for the future design of therapeutic strategies to prevent cell growth in diseases such as cancer.</jats:p