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Because CFTR gene studies now represent one of the most frequent genetic analyses routinely performed worldwide, the number of rare CFTR variants identified in various clinical situations, regularly increases. To provide appropriate diagnosis and prognosis to CF patients as well as appropriate genetic counseling to families, the clinical impact and the phenotypic spectrum of variants identified by diagnostic techniques need to be characterized. Three complementary locus specific databases, called CFTR1, CFTR2 and CFTR -France were developed to address these issues. Besides, the growing knowledge of the CF pathophysiology and the technical evolution in molecular biology allowed to identify candidate modifier genes, regulatory loci, epigenetic profiles and trans -regulators that could help to refine genotype-phenotype correlations at the individual level. These different factors may contribute to the large phenotypic variability between patients with CF, even when they carry identical CFTR variants, regarding lung function, meconium ileus susceptibility or the risk for developing CFTR-related diabetes and liver disease. Finally, the availability of new therapies that target the CFTR protein for numbers of CF patients led to the identification of 'good' and 'poor' responders, thus raising questions of pharmacogenetics factors that may influence treatment efficiency as a novel feature of the complexity of CF patients' management. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved. [ABSTRACT FROM AUTHOR]

Activation of caspase-1 through the inflammasome protein Nalpib controls anthrax lethal toxin (LT)-induced necrosis in murine macrophages. In this study we analyzed physiological changes controlled by caspase-1 in LT-treated murine macrophages. The caspase-1 inhibitor Boc-D-cmk blocked caspase-1 activity and membrane impairment in LT-treated cells. To determine the relationship between caspase-1 activation and membrane integrity, we added Boc-D-cmk to J774A.1 macrophages at different time points following LI exposure. Remark- ably, Boc-D-cmk rescued LT-treated macrophages, even when added at the peak of caspase-1 activation. Late addition of the caspase 1 inhibitor reversed the losses of plasma membrane integrity and metabolic activity in these cells. Similar results were obtained with the proteasome inhibitor MG132, one of the most potent inhibitors of LT toxicity. LT-treated macrophages displaying evidence of membrane impairment recovered upon the addition of MG 132, mirroring the Boc-D-cmk response. Strikingly, late addition of proteasome inhibitors also abrogated caspase-1 activity in LT-treated macrophages. Proteasomal control of caspase-1 activity and membrane impairment, however, was restricted to LT-induced cytolysis, because proteasome inhibitors did not block caspase-1 activation and cell death triggered by lipopolysaccharide and nigericin. Our findings indicate that proteasome inhibitors do not target caspase-1 directly but instead control an upstream event in LT-treated macrophages leading to caspase-1 activation. Taken together, caspase-1-mediated necrosis appears to be tightly controlled and differentially regulated by proteasomes depending on the source of caspase-1 induction. [ABSTRACT FROM AUTHOR]

Germination of Bacillus anthracis spores into the vegetative form is an essential step in anthrax pathogenicity. This process can be triggered in vitro by the common germinants inosine and alanine. Kinetic analysis of B. anthracis spore germination revealed synergy and a sequential mechanism between inosine and alanine binding to their cognate receptors. Because inosine is a critical germinant in vitro, we screened inosine analogs for the ability to block in vitro germination of B. anthracis spores. Seven analogs efficiently blocked this process in vitro. This led to the identification of 6-thioguanosine, which also efficiently blocked spore germination in macrophages and prevented killing of these cells mediated by B. anthracis spores. 6-Thioguanosine shows potential as an anti-anthrax therapeutic agent. [ABSTRACT FROM AUTHOR]

Résumé Les cas d’hypertrypsinémie au dépistage néonatal pour lesquels le diagnostic reste non conclu sont définis soit (1) par l’association d’une mutation au plus du gène CFTR associée à la mucoviscidose avec une concentration de chlorure sudoral intermédiaire entre 30 et 59 mmol/L soit (2) par l’association de 2 mutations de CFTR, dont au moins une est de pathogénicité indéterminée avec une concentration de chlorure sudoral inférieure à 60 mmol/L. Ces situations regroupent des formes cliniques différentes dont il est impossible de prévoir l’évolution. Ceci impose de refaire un test de la sueur à 12 mois et si possible à 6 et 24 mois et de rechercher les mutations rares du gène CFTR . En l’absence de conclusion, des explorations fonctionnelles visant à établir une dysfonction de CFTR peuvent être proposées. Les nourrissons concernés doivent avoir une évaluation initiale au sein d’un centre de ressources et de compétences pour la mucoviscidose (CRCM) comprenant une étude bactériologique des sécrétions bronchiques, une radiologie de thorax et un dosage de l’élastase fécale. Le praticien libéral référent doit être informé des particularités de la prise en charge et travailler en collaboration avec le CRCM. L’enfant doit être revu à 3, 6 et 12 mois, puis tous les ans au CRCM. L’apparition de symptômes évocateurs de mucoviscidose justifie une réévaluation. Ces recommandations établies par le groupe « Dépistage et formes de diagnostic difficile » de la Société française de la mucoviscidose visent à uniformiser les pratiques dans les CRCM pédiatriques français pour un suivi rationnel adapté et éthique. Summary Neonatal screening for cystic fibrosis (CF) may detect infants with elevated immunoreactive trypsinogen (IRT) levels but with inconclusive sweat tests and/or DNA results. This includes cases associating (1) either the presence of at most one CF-causing mutation and sweat chloride values between 30 and 59 mmol/L or (2) two CFTR mutations with at least one of unknown pathogenicity and a sweat chloride below 60 mmol/L. This encompasses different clinical situations whose progression cannot be predicted. These cases require redoing the sweat test at 12 months and if possible at 6 and 24 months of life. This must be associated with extended genotyping. CFTR functional explorations can also help by investigating CFTR dysfunction. These infants must be initially evaluated in dedicated CF centers including bacteriological sputum analysis, chest radiology and fecal elastase dosage. A home practitioner must be informed of the specificity of follow-up. These infants will be reviewed in the CF center at 3, 6 and 12 months and every year. Any CF-related symptom requires reevaluation of the diagnosis. These guidelines were established by the “neonatal screening and difficult diagnoses” working group of the French CF Society. They aim to standardize management of infants with unclear diagnosis in French CF centers. [ABSTRACT FROM AUTHOR]

Summary Neonatal screening for cystic fibrosis (CF) can detect infants with elevated immunoreactive trypsinogen (IRT) levels and inconclusive sweat tests and/or CFTR DNA results. These cases of uncertain diagnosis are defined by (1) either the presence of at most one CF-associated cystic fibrosis transmembrane conductance regulator ( CFTR ) mutation with sweat chloride values between 30 and 59 mmol/L or (2) two CFTR mutations with at least one of unknown pathogenic potential and a sweat chloride concentration below 60 mmol/L. This encompasses various clinical situations whose progression cannot be predicted. In these cases, a sweat chloride test has to be repeated at 12 months, and if possible at 6 and 24 months of life along with extended CFTR sequencing to detect rare mutations. When the diagnosis is not definite, CFTR functional explorations may provide a better understanding of CFTR dysfunction. The initial evaluation of these infants must be conducted in dedicated CF reference centers and should include bacteriological sputum analysis, chest radiology, and fecal elastase assay. The primary care physicians in charge of these patients should be familiar with the current management of CF and should work in collaboration with CF centers. A follow-up should be performed in a CF reference center at 3, 6, and 12 months of life and every year thereafter. Any symptom indicative of CF requires immediate reevaluation of the diagnosis. These guidelines were established by the “neonatal screening and difficult diagnoses” working group of the French CF society. Their objective is to standardize the management of infants with unclear diagnosis. [ABSTRACT FROM AUTHOR]