Publications by authors named "Castel G"

Introduction: Inter- and transdisciplinary research (ITDR) is increasingly promoted to address "wicked problems", particularly in health sectors adopting approaches like Ecohealth. Our Ecohealth-inspired project on rodent-borne diseases, initiated just before the COVID-19 pandemic, provided an opportunity to evaluate ITDR implementation.

Methods: We employed a recently developed semi-quantitative evaluation method to measure our project's success in achieving ITDR and analyzed factors influencing this achievement.

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Article Synopsis
  • XIST long noncoding RNA plays a key role in X chromosome inactivation in placental mammals but is present on both X chromosomes in early human embryos without silencing them.
  • XACT lncRNA accumulates alongside XIST on active X chromosomes and may counteract XIST's functions.
  • Research using human embryonic stem cells reveals that XIST modifies chromatin and reduces transcription of X-linked genes, while XACT's absence does not significantly impact XIST’s activity or gene expression, indicating that XIST has a role prior to XCI and highlights a mechanism of temporary X chromosome dosage compensation.
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Background: Seoul virus (SEOV) is an orthohantavirus primarily carried by rats. In humans, it may cause hemorrhagic fever with renal syndrome (HFRS). Its incidence is likely underestimated and given the expansion of urban areas, a better knowledge of SEOV circulation in rat populations is called for.

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Article Synopsis
  • Orthohantaviruses, primarily transmitted by rodents, cause serious illnesses such as hemorrhagic fever with renal syndrome in Eurasia and hantavirus pulmonary syndrome in the Americas, with no effective treatments or vaccines currently available.
  • The study focused on the Puumala virus (PUUV), carried by bank voles, which causes a milder form of HFRS; researchers developed a hybrid-capture method for complete genomic sequencing of PUUV isolates, revealing valuable information about nucleotide diversity and lineage.
  • The findings offer crucial insights into PUUV evolution and epidemiology in Northern Sweden, highlighting the panel's diagnostic potential that could improve understanding of Orthohantavirus transmission routes.
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Objective: A large and unprecedented outbreak of an attenuated form of hemorrhagic fever with renal syndrome called nephropathia epidemica (NE) and caused by Puumala virus (PUUV) occurred in 2021 in the southern Jura Mountains (France) leading to numerous hospitalizations. The aim of this study was to investigate the circulation of PUUV in its animal reservoir at the time of this outbreak.

Methods: We conjointly surveyed bank vole relative abundance, small mammal community composition, and PUUV circulation in bank voles (seroprevalence and genetic diversity) in the Jura NE epidemic area, between 2020 and 2022.

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The pine processionary moth is a Lepidopteran pest species occurring in the Western Mediterranean. It causes heavy pine defoliations and it is a public and animal health concern because of its urticating caterpillars. Very little is known about the viruses associated to this species, as only two viruses were described so far.

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Background: Understanding the relationships between wildlife biodiversity and zoonotic infectious diseases in a changing climate is a challenging issue that scientists must address to support further policy actions. We aim at tackling this challenge by focusing on small mammal-borne diseases in temperate forests and large urban green spaces. Small mammals are important reservoirs of zoonotic agents, with a high transmission potential for humans and domestic animals.

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Seoul orthohantavirus (SEOV) is not considered a major public health threat on the continent of Africa. However, Africa is exposed to rodentborne SEOV introduction events through maritime traffic after exponential growth of trade with the rest of the world. Serologic studies have already detected hantavirus antibodies in human populations, and recent investigations have confirmed circulation of hantavirus, including SEOV, in rat populations.

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We report results from serologic surveillance for exposure to SARS-CoV-2 among 1,237 wild rodents and small mammals across Europe. All samples were negative, with the possible exception of 1. Despite suspected potential for human-to-rodent spillover, no evidence of widespread SARS-CoV-2 circulation in rodent populations has been reported to date.

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Cell reprogramming has allowed unprecedented access to human development, from virtually any genome. However, reprogramming yields pluripotent stem cells that can differentiate into all cells that form a fetus, but not extraembryonic annexes. Therefore, a cellular model allowing study of placental development from a broad genomic repertoire is lacking.

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One week after fertilization, human embryos implant into the uterus. This event requires the embryo to form a blastocyst consisting of a sphere encircling a cavity lodging the embryo proper. Stem cells can form a blastocyst model that we called a blastoid.

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In Europe, Puumala virus (PUUV) transmitted by the bank vole () is the causative agent of nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome. In France, very little is known about the spatial and temporal variability of the virus circulating within bank vole populations. The present study involved monitoring of bank vole population dynamics and PUUV microdiversity over a ten-year period (2000-2009) in two forests of the Ardennes region: Elan and Croix-Scaille.

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Seoul virus is a zoonotic pathogen carried by the brown rat Rattus norvegicus. Information on its circulation in Africa is limited. In this study, the virus was detected in 37.

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In nature, host specificity has a strong impact on the parasite's distribution, prevalence, and genetic diversity. The host's population dynamics is expected to shape the distribution of host-specific parasites. In turn, the parasite's genetic structure is predicted to mirror that of the host.

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Article Synopsis
  • Understanding how human embryos develop before implantation can enhance reproductive technologies and stem cell research.
  • The study uses advanced techniques like single-cell RNA sequencing to analyze mouse and human embryos' development over time, noting crucial changes in gene expression.
  • Key findings include the timing of different cell types forming and specific markers that indicate development stages, paving the way for better insights into embryonic development.
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Puumala orthohantavirus (PUUV) causes a mild form of haemorrhagic fever with renal syndrome (HFRS) called nephropathia epidemica (NE), regularly diagnosed in Europe. France represents the western frontier of the expansion of NE in Europe with two distinct areas: an endemic area (north-eastern France) where PUUV circulates in rodent populations, with the detection of many human NE cases, and a non-endemic area (south-western France) where the virus is not detected, with only a few human cases being reported. In this study, we describe the different stages of the isolation of two PUUV strains from two distinct French geographical areas: Ardennes (endemic area) and Loiret (non-endemic area).

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Human trophoblast stem cells (hTSCs) derived from blastocysts and first-trimester cytotrophoblasts offer an unprecedented opportunity to study the placenta. However, access to human embryos and first-trimester placentas is limited, thus preventing the establishment of hTSCs from diverse genetic backgrounds associated with placental disorders. Here, we show that hTSCs can be generated from numerous genetic backgrounds using post-natal cells via two alternative methods: (1) somatic cell reprogramming of adult fibroblasts with OCT4, SOX2, KLF4, MYC (OSKM) and (2) cell fate conversion of naive and extended pluripotent stem cells.

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In Europe, Puumala virus (PUUV) is responsible for nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS). Despite the presence of its reservoir, the bank vole, on most of French territory, the geographic distribution of NE cases is heterogeneous and NE endemic and non-endemic areas have been reported. In this study we analyzed whether bank vole-PUUV interactions could partly shape these epidemiological differences.

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Puumala virus (PUUV) in Europe causes nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS). The incidence of NE is highly heterogeneous spatially, whereas the geographic distribution of the wild reservoir of PUUV, the bank vole, is essentially homogeneous. Our understanding of the processes driving this heterogeneity remains incomplete due to gaps in knowledge.

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Article Synopsis
  • Hantaviruses are zoonotic diseases primarily transmitted from rodents to humans, causing illnesses like HFRS and HCPS.
  • A new microarray tool, PathogenID v3.0, has been developed to analyze the genetic diversity of these viruses in Europe, featuring around 800 sequences including 52 specific hantavirus probes.
  • The microarray allows for precise identification of hantavirus species and their geographical variants, successfully characterizing known strains and identifying new variants from locations like France and the UK.
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Background: Ancestral character states computed from the combination of phylogenetic trees with extrinsic traits are used to decipher evolutionary scenarios in various research fields such as phylogeography, epidemiology, and ecology. Despite the existence of powerful methods and software in ancestral character state inference, difficulties may arise when interpreting the outputs of such inferences. The growing complexity of data (trees, annotations), the diversity of optimization criteria for computing trees and ancestral character states, the combinatorial explosion of potential evolutionary scenarios if some ancestral characters states do not stand out clearly from others, requires the design of new methods to explore associations of phylogenetic trees with extrinsic traits, to ease the visualization and interpretation of evolutionary scenarios.

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  • Puumala virus (PUUV) is an RNA virus associated with bank voles and is found across most of Europe, but its evolutionary history remains unclear.
  • This study aims to map the spread of PUUV in Europe since the last postglacial period using an upgraded dataset of viral sequences and new computational methods.
  • The research identifies at least three key dispersal routes of PUUV related to bank vole migrations, indicating a complex pattern of spread from regions like the Alpine-Adriatic to Western and Northern Europe.
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Due to their large geographic distribution and potential high mortality rates in human infections, hantaviruses constitute a worldwide threat to public health. As such, they have been the subject of a large array of clinical, virological and eco-evolutionary studies. Many experiments have been conducted in vitro or on animal models to identify the mechanisms leading to pathogenesis in humans and to develop treatments of hantavirus diseases.

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Motivation: The visualization and interpretation of evolutionary spatiotemporal scenarios is broadly and increasingly used in infectious disease research, ecology or agronomy. Using probabilistic frameworks, well-known tools can infer from molecular data ancestral traits for internal nodes in a phylogeny, and numerous phylogenetic rendering tools can display such evolutionary trees. However, visualizing such ancestral information and its uncertainty on the tree remains tedious.

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The analysis of the nucleoprotein gene of 77 Puumala hantavirus strains detected in human samples in France during 2012-2016 showed that all belonged to the Central European lineage. We observed 2 main clusters, geographically structured; one included strains with the Q64 signature and the other strains with the R64 signature.

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