CERT1 mutations perturb human development by disrupting sphingolipid homeostasis

Neural differentiation, synaptic transmission, and action potential propagation depend on membrane sphingolipids, whose metabolism is tightly regulated. Mutations in the ceramide transporter CERT (CERT1), which is involved in sphingolipid biosynthesis, are associated with intellectual disability, but the pathogenic mechanism remains obscure. Here, we characterize 31 individuals with de novo missense variants in CERT1. Several variants fall into a previously uncharacterized dimeric helical domain that enables CERT homeostatic inactivation, without which sphingolipid production goes unchecked. The clinical severity reflects the degree to which CERT autoregulation is disrupted, and inhibiting CERT pharmacologically corrects morphological and motor abnormalities in a Drosophila model of the disease, which we call ceramide transporter (CerTra) syndrome. These findings uncover a central role for CERT autoregulation in the control of sphingolipid biosynthetic flux, provide unexpected insight into the structural organization of CERT, and suggest a possible therapeutic approach for patients with CerTra syndrome.This work was supported by the National Institute of Neurological Disorders and Stroke (NINDS), NIH (R01NS109858, to VAG); the Paul A. Marks Scholar Program at the Columbia University Vagelos College of Physicians and Surgeons (to VAG); a TIGER grant from the TAUB Institute at the Columbia Vagelos College of Physicians and Scientists (to VAG); the Swiss National Science Foundation (SNF 31003A-179371, to TH); the European Joint Program on Rare Diseases (EJP RD+SNF 32ER30-187505, to TH); the Swiss Cancer League (KFS-4999-02-2020, to GD); the EPFL institutional fund (to GD); the Kristian Gerhard Jebsen Foundation (to GD); the Swiss National Science Foundation (SNSF) (310030_184926, to GD); the Swiss Foundation for Research on Muscle Disease (FSRMM, to MAL); the Natural Science and Engineering Research Council of Canada (Discovery Grant 2020-04241, to JEB); the Italian Ministry of Health Young Investigator Grant (GR-2011-02347754, to EL); the Fondazione Istituto di Ricerca Pediatrica – Città della Speranza (18-04, to EL); the Wroclaw Medical University (SUB.E160.21.004, to RS); the National Science Centre, Poland (2017/27/B/NZ5/0222, to RS); Telethon Undiagnosed Diseases Program (TUDP) (GSP15001); the Temple Street Foundation/Children’s Health Foundation Ireland (RPAC 19-02, to IK); the Deutsche Forschungsgemeinschaft (DFG) (PO2366/2–1, to BP); the Instituto de Salud Carlos III, Spain (to ELM, EBS, and BMD); the National Natural Science Foundation of China (81871079 and 81730036, to HG and KX); and the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH (R01 DK115574, to SSC).The DEFIDIAG study is funded by grants from the French Ministry of Health in the framewok of the national French initiative for genomic medicine. The funders were not involved in the study design, data acquisition, analysis, or writing of the manuscript. Funding for the DECIPHER project was provided by Wellcome. The DDD study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003), a parallel funding partnership between Wellcome and the Department of Health, and the Wellcome Sanger Institute (grant number WT098051). The views expressed in this publication are those of the author(s) and not necessarily those of Wellcome or the Department of Health. The study has UK Research Ethics Committee approval (10/H0305/83, granted by the Cambridge South REC, and GEN/284/12, granted by the Republic of Ireland REC). The research team acknowledges the support of the National Institute for Health Research, through the Comprehensive Clinical Research Network.S

CERT1 mutations perturb human development by disrupting sphingolipid homeostasis

Neural differentiation, synaptic transmission, and action potential propagation depend on membrane sphingolipids, whose metabolism is tightly regulated. Mutations in the ceramide transporter CERT (CERT1), which is involved in sphingolipid biosynthesis, are associated with intellectual disability, but the pathogenic mechanism remains obscure. Here, we characterize 31 individuals with de novo missense variants in CERT1. Several variants fall into a previously uncharacterized dimeric helical domain that enables CERT homeostatic inactivation, without which sphingolipid production goes unchecked. The clinical severity reflects the degree to which CERT autoregulation is disrupted, and inhibiting CERT pharmacologically corrects morphological and motor abnormalities in a Drosophila model of the disease, which we call ceramide transporter (CerTra) syndrome. These findings uncover a central role for CERT autoregulation in the control of sphingolipid biosynthetic flux, provide unexpected insight into the structural organization of CERT, and suggest a possible therapeutic approach for patients with CerTra syndrome

Metabolism and functional effects of plant-derived omega-3 fatty acids in humans

Alpha-linolenic acid (ALA) is an essential fatty acid and the substrate for the synthesis of longer-chain, more un- saturated ω-3 fatty acids, eicosapentaenoic acid (EPA), docosapentaenoic acid and docosahexaenoic acid (DHA). EPA and DHA are associated with human health benefits. The primary source of EPA and DHA is seafood. There is a need for sustainable sources of biologically active ω-3 fatty acids. Certain plants contain high concentrations of ALA and stearidonic acid (SDA). Here we review the literature on the metabolism of ALA and SDA in humans, the impact of increased ALA and SDA consumption on concentrations of EPA and DHA in blood and cell lipid pools, and the extent to which ALA and SDA might have health benefits. Although it is generally considered that humans have limited capacity for conversion of ALA to EPA and DHA, sex differences in conversion to DHA have been identified. If conversion of ALA to EPA and DHA is limited, then ALA may have a smaller health benefit than EPA and DHA. SDA is more readily converted to EPA and appears to offer better potential for health improvement than ALA. However, conversion of both ALA and SDA to DHA is limited in most humans

Dietary exposure to polychlorinated biphenyls (PCB) and risk of Non-Hodgkin's lymphoma: Evidence from the French E3N prospective cohort

International audienceIntroduction: Polychlorinated biphenyls (PCB) are persistent and bioaccumulative lipophilic substances, mostly used in the past by industry. Known to be cancerogenic, PCB are suspected to increase Non-Hodgkin's Lymphoma (NHL) risk in the general population mainly due to evidence from cases-controls studies. Since their interdiction in 1987, diet represents the main route of exposure for the general population, nevertheless no study has assessed the relationship between PCB dietary exposure and NHL risk. The aim of this study was to analyze the association between dietary exposures to dioxin like PCB (DL PCB) and non-dioxin like PCB (NDL PCB) and NHL risk in the E3N prospective cohort of French women. Materials and methods: Among 67,879 women included in this study, 457 cases of NHL were confirmed during 21 years of follow-up. Dietary exposure to PCB was estimated combining food consumption data collected in E3N and food contamination data provided by French Agency for Food, Environmental and Occupational Health & Safety (ANSES) in the second French total diet study. Cox regression models, adjusted for potential confounders, were used to estimate hazard ratio (HR) and 95% confidence intervals (CI). Results: Average age at diagnosis was 67 years. The median dietary exposure to DL PCB and NDL PCB was, 18.5 pg TEQ/d and 138,843.2 pg/d, respectively. While no association was found between dietary exposure to DL PCB or NDL PCB and overall NHL risk, analyses by NHL histological subgroups showed a positive association between dietary exposures to DL PCB and Diffuse Large B Cell Lymphoma (OR3vs1 1.90, 95%CI [1.03–3.51], ptrend 0.02). Nevertheless these findings were no longer statistically significant when the models were adjusted for fish and dairy products consumption. In addition, an inverse association was found between dietary exposure to NDL PCB and the risk of follicular lymphoma (OR3vs1 0.46, 95%CI [0.24–0.87], ptrend 0.01). Conclusion: This is the first study to evaluate the association between dietary exposure to DL and NDL PCB and the risk of NHL in a prospective cohort study. Overall, the findings suggest a lack of association between dietary exposure to DL or NDL PCB and NHL risk. Additional studies are needed to reproduce these findings

Alteration of skeletal and cardiac muscles function in <i>DBA/2J mdx</i> mice background: a focus on high intensity interval training

International audienc

Hepatitis B virus-associated B-cell non-Hodgkin lymphoma in non-endemic areas in Western Europe: Clinical characteristics and prognosis

International audienceThe association between B-cell non-Hodgkin lymphoma (NHL) and hepatitis B virus (HBV) is well demonstrated by epidemiological studies. Most studies concerning this association have been conducted in endemic areas. Thus, little is known concerning the clinical characteristics of HBV-related lymphomas in non-endemic areas. Here, we report the characteristics and outcomes of 39 patients with active HBV infection and B-cell NHL collected retrospectively in France and Italy. We also compared their characteristics with those of HCV-positive patients with NHL. The gender ratio (M/F) was 3.3 and the median age at NHL diagnosis, 59 years. The pathological distribution was 24 (62%) diffuse large B-cell lymphomas (DLBCLs) and 15 (38%) other lymphomas subtypes: marginal zone lymphoma (n = 6), follicular lymphoma (n = 3), mantle cell lymphoma (n = 2), Burkitt's lymphoma (n = 1), and not otherwise specified low-grade B-NHL (n = 3). Treatment included antiviral therapy for 35 patients (90%). Twenty-two (92%) DLBCL patients received an R-CHOP or R-CHOP-like regimen, leading to complete remission for 18 (75%).At one year, 21 DLBCL patients (88%) were alive, and 13 other B-cell lymphoma patients (87%) were alive. This European study underscores the predominance of DLBCL among patients with active HBV infection and their similar outcomes to non-HBV infected patients with DLBCL when treated with R-CHOP and antivirals

Pharmacokinetics and pharmacodynamics of tacrolimus in liver transplant recipients: inside the white blood cells

International audienceObjectivesDespite improvements in patient management and extensive use of therapeutic drug monitoring (TDM), the rate of acute cellular rejection (ACR) remains high in patients treated with tacrolimus (TAC). Moreover, some patients experienced ACR while their whole-blood (WB) concentrations were maintained within the therapeutic range meaning that TDM in WB misrepresents the drug effect. Thus, monitoring TAC directly inside of its effect compartment (intracellular concentrations) or monitoring directly the inhibitory effect on the target protein (calcineurin activity) could be more relevant. The aim of the present study was to explore, in 10 de novo liver transplant recipients, the relationship between TAC whole-blood concentrations, TAC intracellular concentrations and TAC-induced intracellular calcineurin inhibition at day 1 and day 7 after treatment initiation.Design and methodsProspective monocentric observational pharmacokinetic (WB and intracellular concentrations)–pharmacodynamic (calcineurin activity) study.ResultsFull intracellular TAC pharmacokinetic as well as calcineurin activity steady-state profiles is presented in the study. The main result of this study is the lack of relationship between TAC pharmacokinetics (WB and leukocytes) and calcineurin activity in leukocytes at day 1 and day 7 after the graft implantation.ConclusionsDrug monitoring of TAC intracellular concentrations and determination of the calcineurin activity are among future potential biomarkers of acute rejection in transplant recipients. A better knowledge of the relationship between TAC whole blood and intracellular concentrations and calcineurin activity appears necessary before planning clinical trials to evaluate their potential interest as predictive biomarkers

Emergence and dissemination of a linezolid-resistant Staphylococcus capitis clone in Europe

International audienceObjectives: We investigated the epidemiological, clinical, microbiological and genetic characteristics of linezolid-resistant (LZR) Staphylococcus capitis isolates from French ICUs, and compared them with LZR S. capitis isolates from other European countries. Methods: All LZR isolates were subjected to antimicrobial susceptibility testing (AST) and the presence of cfr and optrA genes as well as mutations in the 23S rRNA and ribosomal proteins were investigated using specific PCR with sequencing. The genetic relationship between isolates was investigated using PFGE and WGS. Epidemiological data concerning LZR S. capitis were collected retrospectively in French microbiology laboratories. Results: Twenty-one LZR isolates were studied: 9 from France, 11 from Greece and 1 from Finland. All were resistant to methicillin and aminoglycosides. In addition, this unusual AST profile was identified in S. capitis isolates from seven French hospitals, and represented up to 12% of the S. capitis isolates in one centre. A G2576T mutation in 23S rRNA was identified in all isolates; cfr and optrA genes were absent. All isolates belonged to the same clone on the basis of their PFGE profiles, whatever their geographical origin. WGS found at most 212 SNPs between core genomes of the LZR isolates. Conclusions: We identified and characterized an LZR S. capitis clone disseminated in three European countries, harbouring the same multiple resistance and a G2576T mutation in the 23S rRNA. The possible unrecognized wider distribution of this clone, belonging to a species classically regarded as a low-virulence skin colonizer, is of major concern not least because of the increasing use of oxazolidinones

Neuropsychological Impairment in Detoxified Alcohol-Dependent Subjects with Preserved Psychosocial Functioning

BackgroundChronic alcoholism and its related cognitive impairments are associated with increased social, relational, and professional deficits which have a variable overall impact on social integration. These impairments are known to have varying severities and have rarely been studied among healthy alcohol-dependent subjects with preserved psychosocial functioning. Thus, the objective of this study is to describe neuropsychological performance in this particular population.MethodTwenty-nine socially adjusted alcohol-dependent men, hospitalized for a first or second withdrawal and abstinent for 3 weeks minimum, were compared to 29 healthy non-alcoholic controls. All subjects underwent clinical and psychiatric examination, neuropsychological tests of memory (M), working memory (WM), and executive functions (EF). Comparisons were performed using Student’s t-tests or Mann–Whitney U tests.ResultsNo group differences were found on the Self-Reported Social Adjustment Scale (SAS-SR) or in the Mini-Mental State Examination. Compared to controls, patients had greater episodic, spatial, and WM deficits as well as slightly altered executive functions. In contrast, their executive functions (spontaneous flexibility, criteria generation, rule maintenance, and inhibitory control) were relatively preserved.ConclusionOur sample of socially and professionally integrated alcoholic patients shows fewer cognitive deficits than described in previous studies. Our results suggest that early on, alcohol-dependent subjects develop compensatory adaptation processes to preserve social function and adaptation. Minor cognitive impairments should be screened early in the disease to integrate cognitive interventions into the health-care plan to thus eventually prevent further socio-professional marginalization