A highly efficient, stable, and rapid approach for ex vivo human liver gene therapy via a FLAP lentiviral vector

Allogenic hepatocyte transplantation or autologous transplantation of genetically modified hepatocytes has been used successfully to correct congenital or acquired liver diseases and can be considered as an alternative to orthotopic liver transplantation. However, hepatocytes are neither easily maintained in culture nor efficiently genetically modified and are very sensitive to dissociation before their reimplantation into the recipient. These difficulties have greatly limited the use of an ex vivo approach in clinical trials. In the present study, we have shown that primary human and rat hepatocytes can be efficiently transduced with a FLAP lentiviral vector without the need for plating and culture. Efficient transduction of nonadherent primary hepatocytes was achieved with a short period of contact with vector particles, without modifying hepatocyte viability, and using reduced amounts of vector. We also showed that the presence of the DNA FLAP in the vector construct was essential to reach high levels of transduction. Moreover, transplanted into uPA/SCID mouse liver, lentivirally transduced primary human hepatocytes extensively repopulated their liver and maintained a differentiated and functional phenotype as assessed by the stable detection of human albumin and antitrypsin in the serum of the animals for months. In conclusion, the use of FLAP lentiviral vectors allows, in a short period of time, a high transduction efficiency of human functional and reimplantable hepatocytes. This work therefore opens new perspectives for the development of human clinical trials based on liver-directed ex vivo gene therapy.info:eu-repo/semantics/publishedVersio

Some pioneers of European human genetics

Some of the pioneers of human genetics across Europe are described, based on a series of 100 recorded interviews made by the author. These interviews, and the memories of earlier workers in the field recalled by interviewees, provide a vivid picture, albeit incomplete, of the early years of human and medical genetics. From small beginnings in the immediate post-World War 2 years, human genetics grew rapidly across many European countries, a powerful factor being the development of human cytogenetics, stimulated by concerns over the risks of radiation exposure. Medical applications soon followed, with the recognition of human chromosome abnormalities, the need for genetic counselling, the possibility of prenatal diagnosis and later, the applications of human molecular genetics. The evolution of the field has been strongly influenced by the characters and interests of the relatively small number of founding workers in different European countries, as well as by wider social, medical and scientific factors in the individual countries

TFEB regulates murine liver cell fate during development and regeneration

It is well established that pluripotent stem cells in fetal and postnatal liver (LPCs) can differentiate into both hepatocytes and cholangiocytes. However, the signaling pathways implicated in the differentiation of LPCs are still incompletely understood. Transcription Factor EB (TFEB), a master regulator of lysosomal biogenesis and autophagy, is known to be involved in osteoblast and myeloid differentiation, but its role in lineage commitment in the liver has not been investigated. Here we show that during development and upon regeneration TFEB drives the differentiation status of murine LPCs into the progenitor/cholangiocyte lineage while inhibiting hepatocyte differentiation. Genetic interaction studies show that Sox9, a marker of precursor and biliary cells, is a direct transcriptional target of TFEB and a primary mediator of its effects on liver cell fate. In summary, our findings identify an unexplored pathway that controls liver cell lineage commitment and whose dysregulation may play a role in biliary cancer

La fusion des macrophages : partenaires des cellules Somatiques et cancéreuses ?

La fusion est un mécanisme fondamental utilisé par les organismes multicellulaires. Elle joue un rôle essentiel au cours du développement physiologique. Ainsi, la fusion est-elle le premier événement à l’origine même de la vie lors du contact fusionnel entre spermatozoïde et ovocyte. La fusion des myoblastes en myotubes participe, par la suite, à l’organisation musculaire définitive. La fusion est également rencontrée au cours de processus pathologiques. Les virus en ont fait leur quotidien pour attaquer leurs cellules cibles. La fusion macrophagique est un événement incontournable pour l’obtention de cellules ostéoclastiques et de cellules multinucléées, partenaires essentiels dans des affections comme l’ostéoporose ou les maladies inflammatoires chroniques. Pourtant, les mécanismes moléculaires impliqués dans ces différents événements sont assez mal connus. Un regain d’intérêt est néanmoins récemment apparu lorsque des cellules dérivées de la moelle osseuse ont été retrouvées différenciées en types cellulaires variés dans des tissus lésés. En effet, la fusion entre une cellule d’origine myélomonocytaire, potentiellement macrophagique, et une cellule résidente de l’organe lésé semble être à l’origine de cette plasticité inattendue. Dans cet article, Agnès Vignery revisite la fusion macrophagique et les différentes protéines qui semblent la contrôler avant de s’interroger sur la participation et la pertinence d’un mécanisme équivalent au cours de la cancérogenèse ou de la régénération tissulaire

Construction of a physical, genetic and transcript map of human xq21.1-q21.3

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A high-resolution interval map of the q21 region of the human X chromosome

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