Publications by authors named "Letourneur F"

Autophagy, a cytoprotective mechanism in intestinal epithelial cells, plays a crucial role in maintaining intestinal homeostasis. Beyond its cell-autonomous effects, the significance of autophagy in these cells is increasingly acknowledged in the dynamic interplay between the microbiota and the immune response. In the context of colon cancer, intestinal epithelium disruption of autophagy has been identified as a critical factor influencing tumor development.

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Background: In kidney transplantation, molecular diagnostics may be a valuable approach to improve the precision of the diagnosis. Using next-generation sequencing (NGS), we aimed to identify clinically relevant archetypes.

Methods: We conducted an Illumina bulk RNA sequencing on 770 kidney biopsies (540 kidney recipients) collected between 2006 and 2021 from 11 European centers.

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Radiotherapy represents a major curative treatment for prostate cancer (PCa), but some patients will develop radioresistance (RR) and relapse. The underlying mechanisms remain poorly understood, and miRNAs might be key players in the acquisition and maintenance of RR. Through their encapsulation in small extracellular vesicles (EVs), they can also be relevant biomarkers of radiation response.

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Article Synopsis
  • Polycyclic aromatic hydrocarbons (PAHs), especially benzo(a)pyrene (B(a)P), are harmful environmental contaminants linked to serious health issues like cancer and immune system suppression.
  • This study investigates the use of extracellular vesicles (EVs) and their microRNA (miRNA) content as potential biomarkers for PAH exposure, focusing on changes in EV production and miRNA profiles following exposure to B(a)P.
  • The findings show that B(a)P exposure increases EV production and specifically regulates the expression of miR-342-3p, suggesting that EVs and miRNAs could serve as valuable indicators of PAH exposure in toxicological assessments.
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Bilateral macronodular adrenocortical disease (BMAD) is an uncommon cause of Cushing's syndrome leading to bilateral macronodules. Isolated BMAD has been classified into three molecular groups: patients with ARMC5 alteration, KDM1A alteration, and patients without known genetic cause. The aim of this study was to identify by NGS, in a cohort of 26 patients with BMAD, the somatic alterations acquired in different nodules after macrodissection from patients with germline ARMC5 or KDM1A alterations and to analyze potential somatic alterations in a panel of five other genes involved in adrenal pathology (GNAS, PDE8B, PDE11A, PRKAR1A, and PRKACA).

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Loss of endothelial integrity and vascular leakage are central features of sepsis pathogenesis; however, no effective therapeutic mechanisms for preserving endothelial integrity are available. Here we show that, compared to dermal microvessels, brain microvessels resist infection by Neisseria meningitidis, a bacterial pathogen that causes sepsis and meningitis. By comparing the transcriptional responses to infection in dermal and brain endothelial cells, we identified angiopoietin-like 4 as a key factor produced by the brain endothelium that preserves blood-brain barrier integrity during bacterial sepsis.

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Article Synopsis
  • The study aims to identify easily measurable biomarkers that reflect the biological effects of glucocorticoids in patients with Cushing's syndrome through whole blood transcriptome analysis.
  • It analyzed transcriptomic profiles from blood samples of different patient groups, creating a prediction model that effectively distinguishes between those with overt Cushing's syndrome and other conditions.
  • Findings indicate that the transcriptome can indicate glucocorticoid levels, with FKBP5 expression showing potential as a nonhormonal marker for diagnosing Cushing's syndrome.
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Non-coding RNAs (ncRNAs) are important regulators of gene expression. They are expressed not only in cells, but also in cell-derived extracellular vesicles (EVs). The mechanisms controlling their loading and sorting remain poorly understood.

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Background: A scale for self-assessment of auditory verbal hallucinations (SAVH) was developed for patients, and this study aimed to validate the scale by investigating its psychometric properties.

Methods: Forty one patients with schizophrenia or schizoaffective disorders (DSM-5) self-assessed their hallucinations using nine SAVH questions. Each question was scored from 0 to 5, indicating the severity of the symptoms.

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Foxo family transcription factors are critically involved in multiple processes, such as metabolism, quiescence, cell survival and cell differentiation. Although continuous, high activity of Foxo transcription factors extends the life span of some species, the involvement of Foxo proteins in mammalian aging remains to be determined. Here, we show that Foxo1 is down-regulated with age in mouse T cells.

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Auditory verbal hallucinations (AVH) are experienced by approximately 70 % of patients with schizophrenia and are frequently associated with high levels of distress. Therefore, alleviating hallucinations is an important therapeutic challenge. However, for prescribing a personalized treatment adapted to the patient, an accurate and detailed assessment of AVH is necessary.

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Objective: Mesial Temporal Lobe Epilepsy-associated Hippocampal Sclerosis (MTLE-HS) is a syndrome associated with various aetiologies. We previously identified CD34-positive extravascular stellate cells (CD34+ cells) possibly related to BRAF oncogenic variant in a subset of MTLE-HS. We aimed to identify the BRAF oncogenic variants and characterise the CD34+ cells.

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The amoeba-resistant bacterium causes Legionnaires' disease and employs a type IV secretion system (T4SS) to replicate in the unique, ER-associated -containing vacuole (LCV). The large fusion GTPase Sey1/atlastin is implicated in ER dynamics, ER-derived lipid droplet (LD) formation, and LCV maturation. Here, we employ cryo-electron tomography, confocal microscopy, proteomics, and isotopologue profiling to analyze LCV-LD interactions in the genetically tractable amoeba .

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Article Synopsis
  • * This study aimed to explore how B[a]P affects the expression of certain microRNAs (miRNAs) in PBMCs, using techniques like small RNA deep sequencing to identify miRNAs that respond to B[a]P exposure.
  • * The research found that the miRNA miR-132 is significantly induced by B[a]P in a time- and dose-dependent manner, suggesting it plays a role in regulating cell death mechanisms linked to these
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Host metabolism reprogramming is a key feature of Mycobacterium tuberculosis () infection that enables the survival of this pathogen within phagocytic cells and modulates the immune response facilitating the spread of the tuberculosis disease. Here, we demonstrate that a previously uncharacterized secreted protein from , Rv1813c, manipulates the host metabolism by targeting mitochondria. When expressed in eukaryotic cells, the protein is delivered to the mitochondrial intermembrane space and promotes the enhancement of host ATP production by boosting the oxidative phosphorylation metabolic pathway.

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Introduction: Spondylarthritis (SpA) development in HLA-B27/human β2-microglobulin transgenic rat (B27-rat) is correlated with altered conventional dendritic cell (cDC) function that promotes an inflammatory pattern of CD4+T cells, including a biased expansion of pro-inflammatory Th population and imbalance of regulatory T cells cytokine profile. Transcriptomic analysis revealed that cDCs from B27-rats under express IL-27, an anti-inflammatory cytokine which induces the differentiation of IL-10 regulatory T cells and inhibits Th cells.

Methods: Here, we first investigated whether addition of exogenous IL-27 could reverse the inflammatory pattern observed in CD4 T cells.

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Legionella pneumophila replicates in macrophages and amoeba within a unique compartment, the Legionella-containing vacuole (LCV). Hallmarks of LCV formation are the phosphoinositide lipid conversion from PtdIns(3)P to PtdIns(4)P, fusion with ER-derived vesicles and a tight association with the ER. Proteomics of purified LCVs indicate the presence of membrane contact sites (MCS) proteins possibly implicated in lipid exchange.

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Background & Aims: Axin1 is a negative regulator of wingless-type MMTV integration site family, member 1 (Wnt)/β-catenin signaling with tumor-suppressor function. The Wnt pathway has a critical role in the intestine, both during homeostasis and cancer, but the role of Axin1 remains elusive.

Methods: We assessed the role of Axin1 in normal intestinal homeostasis, with control, epithelial-specific, Axin1-knockout mice (Axin1) and Axin2-knockout mice.

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Toxoplasma gondii is a cyst-forming apicomplexan parasite of virtually all warm-blooded species, with all true cats (Felidae) as definitive hosts. It is the etiologic agent of toxoplasmosis, a disease causing substantial public health burden worldwide. Few intercontinental clonal lineages represent the large majority of isolates worldwide.

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Oligophrenin-1 (OPHN1) is a Rho-GTPase-activating protein (RhoGAP), whose mutations are associated with X-linked intellectual disability (XLID). OPHN1 is enriched at the synapse in both pre- and postsynaptic compartments, where it regulates the RhoA/ROCK/MLC2 signaling pathway, playing a critical role in cytoskeleton remodeling and vesicle recycling. knockout (KO) adult mice display some behavioral deficits in multiple tasks, reminiscent of some symptoms in the human pathology.

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Background: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, which is associated with features of metabolic syndrome. NAFLD may progress in a subset of patients into nonalcoholic steatohepatitis (NASH) with liver injury resulting ultimately in cirrhosis and potentially hepatocellular carcinoma. Today, there is no approved treatment for NASH due to, at least in part, the lack of preclinical models recapitulating features of human disease.

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Male infertility is responsible for approximately half of all cases of reproductive issues. Spermatogenesis originates in a small pool of spermatogonial stem cells (SSCs), which are of interest for therapy of infertility but remain not well defined in humans. Using multiparametric analysis of the side population (SP) phenotype and the α-6 integrin, THY1, and β-2 microglobulin cell markers, we identified a population of human primitive undifferentiated spermatogonia with the phenotype β-2 microglobulin (β-2M)SPα-6THY1, which is highly enriched in stem cells.

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Design: Molecular classification is important for the diagnosis and prognosis of adrenocortical tumors (ACT). Transcriptome profiles separate adrenocortical adenomas 'C2' from carcinomas, and identify two groups of carcinomas 'C1A' and 'C1B', of poor and better prognosis respectively. However, many ACT cannot be profiled because of improper or absent freezing procedures, a mandatory requirement so far.

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Background: Whole-genome sequencing (WGS) is becoming increasingly helpful to assist malaria control programmes. A major drawback of this approach is the large amount of human DNA compared to parasite DNA extracted from unprocessed whole blood. As red blood cells (RBCs) have a diameter of about 7-8 µm and exhibit some deformability, it was hypothesized that cheap and commercially available 5 µm filters might retain leukocytes but much less of Plasmodium falciparum-infected RBCs.

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Background: Despite recent advances in endometrial carcinoma (EC) molecular characterization, its prognostication remains challenging. We aimed to assess whether RNAseq could stratify EC patient prognosis beyond current classification systems.

Methods: A prognostic signature was identified using a LASSO-penalized Cox model trained on TCGA (N = 543 patients).

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