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Hadoux J.,University Paris - Sud | Feraud O.,University Paris - Sud | Griscelli F.,University Paris - Sud | Opolon P.,Laboratoire Of Pathologie Experimentale | And 5 more authors.
Stem Cell Research | Year: 2016

Multiple Endocrine Neoplasia Type 2A (MEN2A) is a cancer-predisposing syndrome that affects patients with germline RET mutations. The clinical spectrum of the syndrome includes medullary thyroid carcinoma (MTC), pheochromocytoma, hyperparathyroidism and cutaneous lichen amyloidosis (CLA) and/or Hirschsprung disease in some variants. Currently, there is no satisfactory animal model recapitulating all the features of the disease especially at the level of stem cells. We generated induced pluripotent stem cells (iPSCs) from a patient with RET mutation at codon 634 who developed pheochromocytoma and MTC. RETC634Y-mutated cells were reprogrammed by non-integrative viral transduction. These iPSCs had normal karyotype, harboured the RETC634Y mutation and expressed pluripotency hallmarks as well as RET. A comprehensive pathological assessment of teratoma was performed after injection in immunodeficient mice. © 2016 The Authors.


PubMed | Laboratoire Of Pathologie Experimentale, Gustave Roussy and University Paris - Sud
Type: Journal Article | Journal: Stem cell research | Year: 2016

Multiple Endocrine Neoplasia Type 2A (MEN2A) is a cancer-predisposing syndrome that affects patients with germline RET mutations. The clinical spectrum of the syndrome includes medullary thyroid carcinoma (MTC), pheochromocytoma, hyperparathyroidism and cutaneous lichen amyloidosis (CLA) and/or Hirschsprung disease in some variants. Currently, there is no satisfactory animal model recapitulating all the features of the disease especially at the level of stem cells. We generated induced pluripotent stem cells (iPSCs) from a patient with RET mutation at codon 634 who developed pheochromocytoma and MTC. RET


PubMed | Laboratoire Of Pathologie Experimentale and University Paris - Sud
Type: Journal Article | Journal: Stem cell research | Year: 2016

Chronic myeloid leukemia (CML) is a clonal malignancy initiated by the occurrence of a t (9;22) translocation, generating Ph1 chromosome and BCR-ABL oncogene in a primitive hematopoietic stem cell (HSC). The resistance of HSC to targeted therapies using tyrosine kinase inhibitors remains a major obstacle towards the cure. We have generated an iPSC line from a patient with CML using leukemic CD34+ cells cryopreserved at diagnosis. Ph1+ CML cells were reprogrammed by non-integrative viral transduction. These iPSCs harboured Ph1 chromosome and expressed pluripotency hallmarks as well as BCR-ABL. Teratoma assays revealed normal differentiation after injection in immunodeficient mice.


PubMed | Laboratoire Of Pathologie Experimentale, French Institute of Health and Medical Research, CNRS Genetics, Immunotherapy, Chemistry & Cancer Laboratory, University of Paris Descartes and 2 more.
Type: | Journal: Scientific reports | Year: 2016

Hematopoietic stem cells (HSCs) undergo self-renewal to maintain hematopoietic homeostasis for lifetime, which is regulated by the bone marrow (BM) microenvironment. The chemokine receptor CXCR4 and its ligand CXCL12 are critical factors supporting quiescence and BM retention of HSCs. Here, we report an unknown function of CXCR4/CXCL12 axis in the protection of HSCs against oxidative stress. Disruption of CXCR4 receptor in mice leads to increased endogenous production of reactive oxygen species (ROS), resulting in p38 MAPK activation, increased DNA double-strand breaks and apoptosis leading to marked reduction in HSC repopulating potential. Increased ROS levels are directly responsible for exhaustion of the HSC pool and are not linked to loss of quiescence of CXCR4-deficient HSCs. Furthermore, we report that CXCL12 has a direct rescue effect on oxidative stress-induced HSC damage at the mitochondrial level. These data highlight the importance of CXCR4/CXCL12 axis in the regulation of lifespan of HSCs by limiting ROS generation and genotoxic stress.


Le Bars H.,University of Rennes 2 – Upper Brittany | Le Gall-David S.,University of Rennes 2 – Upper Brittany | Renoux V.M.,Laboratoire Of Pathologie Experimentale | Bonnaure-Mallet M.,University of Rennes 2 – Upper Brittany | And 2 more authors.
Veterinary Microbiology | Year: 2012

In this study, we investigated adherence and motility of the hypermutator Salmonella enterica Heidelberg B182 bovine strain related to a 12. bp deletion in mutS. This mutator phenotype was associated with increased adherence to epithelial cells and with high expression of fimA as shown by real-time RT-PCR. Motility studies showed that fliC were up-regulated in the B182 strain, while fljA and fljB were down-regulated.In order to determine if mutated mutS is implicated in this genes expression, isogenic strains, derived from a WT strain, containing the 12. bp deletion in mutS (Δ12bpmutS) or an inactivated mutS (ΔmutS) were generated Δ12bpmutS and ΔmutS strains showed a spontaneous mutation rate similar to the environmental strain B182, but exhibited lower adherence capacity and fimA expression. In contrast to the fimbriae genes, in Δ12bpmutS, fliC expression was up-regulated, but fljA and fljB expression were decreased, as in the B182 strain. Only fljB expression was increased in ΔmutS mutants.Taken together, our data suggest that mutS alteration does not influence fimbriae expression but can impact flagella genes. © 2012 Elsevier B.V.

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