Régulation par phosphorylation du facteur de transcription MafA

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Innovative Therapies for Hemoglobin Disorders

International audienceBêta-globin gene transfer has been used as a paradigm for hematopoietic stem cell (HSC) gene therapy, but is subject to major difficulties, such as the lack of selection of genetically corrected HSCs, the need for high-level expression of the therapeutic gene, and cell-specific transgene expression. It took more than 40 years for scientists and physicians to advance from the cloning of globin gene and discovering globin gene mutations to improving our understanding of the pathophysiological mechanisms involved, the detection of genetic modifiers, the development of animal models and gene transfer vectors, comprehensive animal testing, and demonstrations of phenotypic improvement in clinical trials, culminating in the authorization of the first gene therapy product for bêta-thalassemia in 2019. Research has focused mostly on the development of lentiviral gene therapy vectors expressing variants of the gamma-globin gene, or more recently targeting a -globin repressor, some of which have entered clinical testing and should soon diversify the available treatments and promote price competition. These results are encouraging, but we have yet to reach the end of the story. New molecular and cellular tools, such as gene editing or the development of induced pluripotent stem cells, are being developed, heralding the emergence of alternative products, the efficacy and safety of which are being studied. Hemoglobin disorders constitute an important model for testing the pros and cons of these advanced technologies, some of which are already in the clinical phase. In this review, we focus on the development of the advanced products, and recent technological innovations which could lead to clinical trials in the near future, and provide hope for a definitive cure of these severe conditions

Ex Vivo Selection of Transduced Hematopoietic Stem Cells for Gene Therapy of β-Hemoglobinopathies

International audienceAlthough gene transfer to hematopoietic stem cells (HSCs) has shown therapeutic efficacy in recent trials for several individuals with inherited disorders, transduction incompleteness of the HSC population remains a hurdle to yield a cure for all patients with reasonably low integrated vector numbers. In previous attempts at HSC selection, massive loss of transduced HSCs, contamination with non-transduced cells, or lack of applicability to large cell populations has rendered the procedures out of reach for human applications. Here, we fused codon-optimized puromycin N-acetyltransferase to herpes simplex virus thymidine kinase. When expressed from a ubiquitous promoter within a complex lentiviral vector comprising the b AT87Q-globin gene, viral titers and therapeutic gene expression were maintained at effective levels. Complete selection and preservation of transduced HSCs were achieved after brief exposure to puromycin in the presence of MDR1 blocking agents, suggesting the procedure's suitability for human clinical applications while affording the additional safety of conditional suicide

Fanconi DNA repair pathway is required for survival and long-term maintenance of neural progenitors

Although brain development abnormalities and brain cancer predisposition have been reported in some Fanconi patients, the possible role of Fanconi DNA repair pathway during neurogenesis is unclear. We thus addressed the role of fanca and fancg, which are involved in the activation of Fanconi pathway, in neural stem and progenitor cells during brain development and adult neurogenesis. Fanca−/− and fancg−/− mice presented with microcephalies and a decreased neuronal production in developing cortex and adult brain. Apoptosis of embryonic neural progenitors, but not that of postmitotic neurons, was increased in the neocortex of fanca−/− and fancg−/− mice and was correlated with chromosomal instability. In adult Fanconi mice, we showed a reduced proliferation of neural progenitor cells related to apoptosis and accentuated neural stem cells exhaustion with ageing. In addition, embryonic and adult Fanconi neural stem cells showed a reduced capacity to self-renew in vitro. Our study demonstrates a critical role for Fanconi pathway in neural stem and progenitor cells during developmental and adult neurogenesis