Preclinical corrective gene transfer in Xeroderma pigmentosum human skin stem cells

Xeroderma pigmentosum (XP) is a devastating disease associated with dramatic skin cancer proneness. XP cells are deficient in nucleotide excision repair (NER) of bulky DNA adducts including ultraviolet (UV)-induced mutagenic lesions. Approaches of corrective gene transfer in NER-deficient keratinocyte stem cells hold great hope for the long-term treatment of XP patients. To face this challenge, we developed a retrovirus-based strategy to safely transduce the wild-type XPC gene into clonogenic human primary XP-C keratinocytes. De novo expression of XPC was maintained in both mass population and derived independent candidate stem cells (holoclones) after more than 130 population doublings (PD) in culture upon serial propagation (> 10(40) cells). Analyses of retrovirus integration sequences in isolated keratinocyte stem cells suggested the absence of adverse effects such as oncogenic activation or clonal expansion. Furthermore, corrected XP-C keratinocytes exhibited full NER capacity as well as normal features of epidermal differentiation in both organotypic skin cultures and in a preclinical murine model of human skin regeneration in vivo. The achievement of a long-term genetic correction of XP-C epidermal stem cells constitutes the first preclinical model of ex vivo gene therapy for XP-C patients.F.L. was supported in part by grants PI081054 from ISCIII and PBIO-0306-2006 from Comunidad de Madrid (CAM). M.D.R. was supported by grant SAF2010-16976 from MICINN. The authors declared no conflict of interest

Identifying a Window of Vulnerability during Fetal Development in a Maternal Iron Restriction Model

It is well acknowledged from observations in humans that iron deficiency during pregnancy can be associated with a number of developmental problems in the newborn and developing child. Due to the obvious limitations of human studies, the stage during gestation at which maternal iron deficiency causes an apparent impairment in the offspring remains elusive. In order to begin to understand the time window(s) during pregnancy that is/are especially susceptible to suboptimal iron levels, which may result in negative effects on the development of the fetus, we developed a rat model in which we were able to manipulate and monitor the dietary iron intake during specific stages of pregnancy and analyzed the developing fetuses. We established four different dietary-feeding protocols that were designed to render the fetuses iron deficient at different gestational stages. Based on a functional analysis that employed Auditory Brainstem Response measurements, we found that maternal iron restriction initiated prior to conception and during the first trimester were associated with profound changes in the developing fetus compared to iron restriction initiated later in pregnancy. We also showed that the presence of iron deficiency anemia, low body weight, and changes in core body temperature were not defining factors in the establishment of neural impairment in the rodent offspring

Adapting Agriculture to Climate Change: A Synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across Five Continents

The Adapting Agriculture to Climate Change Project set out to improve the diversity, quantity, and accessibility of germplasm collections of crop wild relatives (CWR). Between 2013 and 2018, partners in 25 countries, heirs to the globetrotting legacy of Nikolai Vavilov, undertook seed collecting expeditions targeting CWR of 28 crops of global significance for agriculture. Here, we describe the implementation of the 25 national collecting programs and present the key results. A total of 4587 unique seed samples from at least 355 CWR taxa were collected, conserved ex situ, safety duplicated in national and international genebanks, and made available through the Multilateral System (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty). Collections of CWR were made for all 28 targeted crops. Potato and eggplant were the most collected genepools, although the greatest number of primary genepool collections were made for rice. Overall, alfalfa, Bambara groundnut, grass pea and wheat were the genepools for which targets were best achieved. Several of the newly collected samples have already been used in pre-breeding programs to adapt crops to future challenges.info:eu-repo/semantics/publishedVersio

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Les protéines KIN17, XPC, DNA-PKCS et XRCC4 dans la réponse cellulaire aux dommages de l'ADN. Etude des relations entre la réparation par excision de nucléotides et la recombinaison non homologué dans un modèle syngénique humain

Au cours de la vie cellulaire, l ADN, support de l information génétique, est soumis à des atteintes d origine endogène ou exogène qui entraînent une grande variété de modifications. Si elles ne sont pas réparées correctement, les lésions de l ADN peuvent causer l apparition de mutations et entraîner instabilité génétique et cancer (pour revue voir Hoeijmakers, 2001).Les liaisons chimiques au sein de la double hélice d ADN peuvent s altérer spontanément : perte du groupement amino-exocyclique (déamination) ou hydrolyse de la liaison des bases au désoxyribose (dépurination ou dépyrimidination). Malgré une fidélité importante, il arrive également que la machinerie de réplication de l ADN commette des erreurs ...PARIS5-BU-Necker : Fermée (751152101) / SudocSudocFranceF

Irradiation par microfaisceau de particules alpha (implication des espèces réactives de l'oxygène dans l'effet de voisinage)

L effet de voisinage radio-induit s observe dans les cellules voisines de cellules irradiées mais non directement touchée par l irradiation. A ce jour, les radicaux libres sont considérés comme ayant un rôle actif dans la survenue de réponse au voisinage, mais leur implication n est pas encore totalement définie. Afin de déterminer leur impact dans la réponse au voisinage, à la fois temporellement et spatialement, des irradiations par microfaisceau de particules alpha sont mises au point afin de cibler une fraction définie de cellules au niveau du noyau dans une culture cellulaire avec un nombre prédéterminé d ions. Les irradiations sont pratiquées sur des cellules normales ostéoblastiques à sous-confluence nommée MC3T3-E1. Deux sources distinctes sont ici identifiées dans les cellules comme productrices d espèces réactives de l oxygène après irradiation ciblée : la membrane cytoplasmique et les mitochondries. L inhibition du stress oxydatif général observé après irradiation par la filipin (déstructurant les radeaux lipidiques) met en évidence le rôle primordial de la membrane dans la survenue d effet de voisinage. Les conséquences cellulaires de l effet de voisinage sont aussi étudiées à l échelle de la cellule en termes de mort cellulaire et induction de micronoyaux. Une fraction de 10 à 100% de cellules est individuellement ciblée dans la population cellulaire. Dans ce cas, l induction de mort mitotique et de micronoyaux augmentent dans les cellules voisines, ainsi que dans les cellules directement irradiées. Ces observations démontrent un impact de l effet de voisinage entre cellules irradiées selon un mode autocrine ou paracrine. Ce mémoire indique une interaction complexe entre signaux relatifs à l irradiation et signaux relatifs à l effet de voisinage (dépendant de la membrane) conduisant à une amplification.de la réponse cellulaire originelleIonizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise alpha-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondira like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10% to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF