Importation nucléaire de protéines et de plasmides médiatisée par des osides caryophiles

Une limite majeure à l'utilisation des vecteurs non viraux pour la thérapie génique est leur difficulté à transférer les gènes dans le noyau, site de leur expression.Pour favoriser l'importation nucléaire, notre approche a consisté à associer des signaux de localisation nucléaire osidiques (osides caryophiles) à des plasmides. Nous avons montré que le transport nucléaire médiatisé par des signaux osidiques est différent de la voie classique utilisant des peptides de localisation nucléaire. Celui-ci n'est pas inhibé sous diverses conditions de stress et est très efficace dans des cellules quiescentes. Les plasmides substitués par un oside caryophile, le mannose, sont importés dans le noyau de cellules perméabilisées par la digitonine. L'expression de ces plasmides est jusqu'à 250 fois plus grande qu'avec des plasmides modifiés mais non mannosylés.Ce travail ouvre la voie à la préparation de plasmides glycosylés efficaces, potentiellement utilisables en thérapie génique.ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Fertility Preservation in Klinefelter Syndrome Patients during the Transition Period.

International audienceSpermatozoa have occasionally been identified in ejaculate of adult Klinefelter syndrome (KS) patients but very exceptionally in KS adolescents. Spermatozoa can also be retrieved in testicular tissue of KS adolescents. The testis may also harbor spermatogonia and noncompletely differentiated germ cells. Neither clinical features nor hormonal parameters could predict germ cell recovery in KS adults or adolescents. No predictive factors can actually demonstrate that early diagnosis of KS would allow increasing the chance of sperm retrieval even if it has been suggested that semen quality may decline with age in KS patients. Leydig cell dysfunction may also be another factor that might affect the spermatogenesis process in XXY adolescents. Fertility preservation might be preferentially proposed in KS adolescents when semen sampling is possible, when the patient is able to consider alternative options to become a father, and to accept germ cell retrieval failure. However, precocious diagnosis of KS has also to be considered because it might not solely improve the possibility of fertility preservation after the onset of puberty, but also the medical care and the quality of life of these patients

Exposure to Chemotherapy During Childhood or Adulthood and Consequences on Spermatogenesis and Male Fertility

International audienceOver the last decade, the number of cancer survivors has increased thanks to progress in diagnosis and treatment. Cancer treatments are often accompanied by adverse side effects depending on the age of the patient, the type of cancer, the treatment regimen, and the doses. The testicular tissue is very sensitive to chemotherapy and radiotherapy. This review will summarize the epidemiological and experimental data concerning the consequences of exposure to chemotherapy during the prepubertal period or adulthood on spermatogenic progression, sperm production, sperm nuclear quality, and the health of the offspring. Studies concerning the gonadotoxicity of anticancer drugs in adult survivors of childhood cancer are still limited compared with those concerning the effects of chemotherapy exposure during adulthood. In humans, it is difficult to evaluate exactly the toxicity of chemotherapeutic agents because cancer treatments often combine chemotherapy and radiotherapy. Thus, it is important to undertake experimental studies in animal models in order to define the mechanism involved in the drug gonadotoxicity and to assess the effects of their administration alone or in combination on immature and mature testis. These data will help to better inform cancer patients after recovery about the risks of chemotherapy for their future fertility and to propose fertility preservation options

Paradoxical risk of reduced fertility after exposure of prepubertal mice to vincristine or cyclophosphamide at low gonadotoxic doses in humans

Abstract Cancer treatment can have long-term side effects in cured patients and infertility is one of them. Given the urgency of diagnosis in children with cancer, the toxicity of treatments on the gonad was overshadowed for a long time. In the present study, prepubertal mice were treated by vincristine or cyclophosphamide commonly used in acute leukaemia treatment. The prepubertal exposure to cyclophosphamide, at a low gonadotoxic dose in humans (< 3.5 g/m 2 ), led to morphological alterations of prepubertal testicular tissue. An increased proportion of spermatozoa with hypocondensed chromatin and oxidized DNA associated with decreased fertility were uncovered at adulthood. Short- and long-term morphological alterations of the testicular tissue, disturbed progression of spermatogenesis along with increased proportions of isolated flagella and spermatozoa with fragmented DNA were evidenced in vincristine-treated mice. Moreover, the fertility of mice exposed to vincristine was severely affected despite being considered low-risk for fertility in humans. Paternal exposure to vincristine or cyclophosphamide before puberty had no impact on offspring development. Contrary to the current gonadotoxic risk classification, our results using a mouse model show that vincristine and cyclophosphamide (< 3.5 g/m 2 ) present a high gonadotoxic risk when administered before the initiation of spermatogenesis

Genetic identification of intracellular trafficking regulators involved in notch dependent binary cell fate acquisition following asymmetric cell division.: Notch intracellular trafficking regulators

International audienceNotch signaling is involved in numerous cellular processes during development and throughout adult life. Although ligands and receptors are largely expressed in the whole organism, activation of Notch receptors only takes place in a subset of cells and/or tissues and is accurately regulated in time and space. Previous studies have demonstrated that endocytosis and recycling of both ligands and/or receptors are essential for this regulation. However, the precise endocytic routes, compartments and regulators involved in the spatio temporal regulation are largely unknown.In order to identify Notch signaling intracellular trafficking regulators, we have undertaken a tissue-specific dsRNA genetic screen against candidates potentially involved in endocytosis and recycling within the endolysosomal pathway. dsRNA against 418 genes was induced in Drosophila melanogaster sensory organ lineage in which Notch signaling regulates binary cell fate acquisition. Gain- or loss-of Notch signaling phenotypes were observed in adult sensory organs for 113 of them. Furthermore, 26 genes presented a change in the steady state localization of Notch, Sanpodo, a Notch co-factor, and/or Delta in the pupal lineage. In particular, we identified 20 genes with previously unknown function in Drosophila melanogaster intracellular trafficking. Among them, we identified CG2747 and show that it regulates the localization of clathrin adaptor AP-1 complex, a negative regulator of Notch signaling. All together, our results further demonstrate the essential function of intracellular trafficking in regulating Notch signaling-dependent binary cell fate acquisition and constitute an additional step toward the elucidation of the routes followed by Notch receptor and ligands to signal

Dynamics of epigenetic modifications in ICSI embryos from in vitro‐produced spermatozoa

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Does soaking temperature during controlled slow freezing of pre-pubertal mouse testes influence course of in vitro spermatogenesis?

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Evaluation of sperm nuclear integrity in patients with different percentages of decapitated sperm in ejaculates

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