ABCG2 Is Overexpressed on Red Blood Cells in Ph-Negative Myeloproliferative Neoplasms and Potentiates Ruxolitinib-Induced Apoptosis

Acknowledgments: The authors would like to thank Dominique Gien, Sirandou Tounkara, and Eliane Véra at Centre National de Référence pour les Groupes Sanguins for the management of blood samples. Funding: The work was supported by Institut National de la Santé et de la Recherche Médicale (Inserm), Institut National de la Transfusion Sanguine (INTS), the University of Paris, and grants from Laboratory of Excellence (Labex) GR-Ex, reference No. ANR-11-LABX-0051. The Labex GR-Ex is funded by the IdEx program “Investissements d’avenir” of the French National Research Agency, reference No. ANR-18-IDEX-0001. R.B. was funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement No. 675115-RELEVANCE-H2020-MSCA-ITN-2015. M.B. was funded by Ministère de l’Enseignement Supérieur et de la Recherche at the BioSPC Doctoral School. R.B. and M.B. also received financial support from Société Française d’Hématologie (SFH) and Club du Globule Rouge et du Fer (CGRF).Peer reviewedPublisher PD

Altered Ca2+ Homeostasis in Red Blood Cells of Polycythemia Vera Patients Following Disturbed Organelle Sorting during Terminal Erythropoiesis

The authors thank Thierry Peyrard, Dominique Gien, Sirandou Tounkara, and Eliane Véra at Centre National de Référence pour les Groupes Sanguins for the management of blood samples. The authors thank Sandrine Genetet and Isabelle Mouro-Chanteloup at the Inserm UMR_S1134 unit for their assistance in experiments. The authors also thank Michaël Dussiot at the Institute Imagine for his assistance in imaging flow cytometry. We thank Johanna Bruce and Virginie Salnot at 3P5 Proteomics Platform for sample preparation and analysis, and François Guillonneau and Patrick Mayeux for their management and strategies. Funding: The work was supported by Institut National de la Santé et de la Recherche Médicale (Inserm); Institut National de la Transfusion Sanguine (INTS); the University of Paris; and grants from Laboratory of Excellence (Labex) GR-Ex, reference No. ANR-11-LABX-0051. The Labex GR- Ex is funded by the IdEx program “Investissements d’avenir” of the French National Research Agency, reference No. ANR-11-IDEX-0005-02 and ANR-18-IDEX-0001. R.B., M.G.R., and D.M.A. were funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement No. 675115-RELEVANCE-H2020-MSCA-ITN-2015. R.B. also received financial support from Société Française d’Hématologie (SFH) and Club du Globule Rouge et du Fer (CGRF). R.B. is currently funded by the Innovate UK Research and Innovation Knowledge Transfer Partnership (KTP) between University of Aberdeen and Vertebrate Antibodies Ltd. (Partnership No. KTP12327). T.D. was supported by PhD grants from Université Paris Saclay MESR (Ministère Enseignement Supérieur et de la Recherche) and then FRM (Fondation recherche médicale). The Orbitrap Fusion mass spectrometer was acquired with funds from Fonds Europeen de Developpement Regional (FEDER) through the Operational Program for Competitiveness Factors and Employment 2007-2013 and from the Canceropole Ile de France.Peer reviewedPublisher PD

Despite mutation acquisition in hematopoietic stem cells, JMML-propagating cells are not always restricted to this compartment

Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative neoplasm of early childhood, initiated by RAS-activating mutations. Genomic analyses have recently described JMML mutational landscape; however, the nature of JMML-propagating cells (JMML-PCs) and the clonal architecture of the disease remained until now elusive. Combining genomic (exome, RNA-seq), Colony forming assay and xenograft studies, we detect the presence of JMML-PCs that faithfully reproduce JMML features including the complex/nonlinear organization of dominant/minor clones, both at diagnosis and relapse. Further integrated analysis also reveals that although the mutations are acquired in hematopoietic stem cells, JMML-PCs are not always restricted to this compartment, highlighting the heterogeneity of the disease during the initiation steps. We show that the hematopoietic stem/progenitor cell phenotype is globally maintained in JMML despite overexpression of CD90/THY-1 in a subset of patients. This study shed new lights into the ontogeny of JMML, and the identity of JMML-PCs, and provides robust models to monitor the disease and test novel therapeutic approaches

Etude de l'hétérogénéité moléculaire et de la réponse thérapeutique des néoplasies myéloprolifératives BCR-ABL1 négatives

PARIS-BIUP (751062107) / SudocSudocFranceF

Regulation of the transcriptional activity of nuclear receptors by the MEK/ERK1/2 pathway

Cells undergo continuous and simultaneous external influences regulating their behavior. As an example, during differentiation, they go through different stages of maturation and gene expression is regulated by several simultaneous signaling pathways. We often tend at separating the nuclear pathways from the signaling ones initiated at membrane receptors. However, it is essential to keep in mind that all these pathways are interconnected to achieve a fine regulation of cell functions. The regulation of transcription by nuclear receptors has been thoroughly studied, but it now appears that a critical level of this regulation involves the action of several kinases that target the nuclear receptors themselves as well as their partners. The purpose of this review is to highlight the importance of one family of the mitogen-activated protein kinase (MAPK) superfamily, the MEK/ERK1/2 pathway, in the transcriptional activity of nuclear receptors

Development of a Real-Time PCR Assay for Quantitative Detection of Encephalitozoon intestinalis DNA

A new real-time PCR assay for quantitation of Encephalitozoon intestinalis DNA was developed which used a TaqMan fluorescent probe for specific detection. Serial dilutions of E. intestinalis spore suspensions obtained from tissue culture were used as external standards. The detection limit of the technique was 20 spores per ml, with a good interassay reproducibility (coefficient of variation of 7.1% for the suspension containing 20 spores/ml, 5.0% for the suspension containing 75 spores/ml and below 3.5% for higher concentrations). Quantitative detection of E. intestinalis DNA was similar whether the serial dilutions of spores were made in distilled water or in a stool suspension, allowing the use of the assay for stool specimens. The assay was then applied to 14 clinical specimens from 8 immunocompromised patients with proven E. intestinalis infection. The quantitation of the parasitic burden was achieved in stools, blood, urine, tissue biopsies, and bronchopulmonary specimens. The highest parasitic burdens were noted in stools, urine, and bronchopulmonary specimens, reaching 10(5) to 10(6) spores/g or ml. Dissemination of the infection was also evidenced in some patients by demonstration of E. intestinalis DNA in blood and serum. We conclude that real-time PCR is a valuable tool for quantitation of E. intestinalis burden in clinical specimens

Inhibitory Activity of Human Immunodeficiency Virus Aspartyl Protease Inhibitors against Encephalitozoon intestinalis Evaluated by Cell Culture-Quantitative PCR Assay

Immune reconstitution might not be the only factor contributing to the low prevalence of microsporidiosis in human immunodeficiency virus (HIV)-infected patients treated with protease inhibitors, as these drugs may exert a direct inhibitory effect against fungi and protozoa. In this study, we developed a cell culture-quantitative PCR assay to quantify Encephalitozoon intestinalis growth in U-373-MG human glioblastoma cells and used this assay to evaluate the activities of six HIV aspartyl protease inhibitors against E. intestinalis. A real-time quantitative PCR assay targeted the E. intestinalis small-subunit rRNA gene. HIV aspartyl protease inhibitors were tested over serial concentrations ranging from 0.2 to 10 mg/liter, with albendazole used as a control. Ritonavir, lopinavir, and saquinavir were able to inhibit E. intestinalis growth, with 50% inhibitory concentrations of 1.5, 2.2, and 4.6 mg/liter, respectively, whereas amprenavir, indinavir, and nelfinavir had no inhibitory effect. Pepstatin A, a reference aspartyl protease inhibitor, could also inhibit E. intestinalis growth, suggesting that HIV protease inhibitors may act through the inhibition of an E. intestinalis-encoded aspartyl protease. These results showed that some HIV protease inhibitors can inhibit E. intestinalis growth at concentrations that are achievable in vivo and that the real-time quantitative PCR assay that we used is a valuable tool for the in vitro assessment of the activities of drugs against E. intestinalis