23 research outputs found
The HOXB4 Homeoprotein Promotes the Ex Vivo Enrichment of Functional Human Embryonic Stem Cell-Derived NK Cells
Human embryonic stem cells (hESCs) can be induced to differentiate into blood cells using either co-culture with stromal cells or following human embryoid bodies (hEBs) formation. It is now well established that the HOXB4 homeoprotein promotes the expansion of human adult hematopoietic stem cells (HSCs) but also myeloid and lymphoid progenitors. However, the role of HOXB4 in the development of hematopoietic cells from hESCs and particularly in the generation of hESC-derived NK-progenitor cells remains elusive. Based on the ability of HOXB4 to passively enter hematopoietic cells in a system that comprises a co-culture with the MS-5/SP-HOXB4 stromal cells, we provide evidence that HOXB4 delivery promotes the enrichment of hEB-derived precursors that could differentiate into fully mature and functional NK. These hEB-derived NK cells enriched by HOXB4 were characterized according to their CMH class I receptor expression, their cytotoxic arsenal, their expression of IFNÎł and CD107a after stimulation and their lytic activity. Furthermore our study provides new insights into the gene expression profile of hEB-derived cells exposed to HOXB4 and shows the emergence of CD34+CD45RA+ precursors from hEBs indicating the lymphoid specification of hESC-derived hematopoietic precursors. Altogether, our results outline the effects of HOXB4 in combination with stromal cells in the development of NK cells from hESCs and suggest the potential use of HOXB4 protein for NK-cell enrichment from pluripotent stem cells
Ternary Complexes with Poly(ÎČ-cyclodextrin), Cationic Surfactant, and Polyanion in Dilute Aqueous Solution:Â A Viscometric and Small-Angle Neutron Scattering Study
The HOXB4 Homeoprotein Differentially Promotes Ex Vivo Expansion of Early Human Lymphoid Progenitors
International audienc
Temperature Effect on Ionic Current and ssDNA Transport through Nanopores
International audienceWe have investigated the role of electrostatic interactions in the transport of nucleic acids and ions through nanopores. The passage of DNA through nanopores has so far been conjectured to involve a free-energy barrier for entry, followed by a downhill translocation where the driving voltage accelerates the polymer. We have tested the validity of this conjecture by using two toxins, α-hemolysin and aerolysin, which differ in their shape, size, and charge. The characteristic timescales in each toxin as a function of temperature show that the entry barrier is âŒ15kBT and the translocation barrier is âŒ35kBT, although the electrical force in the latter step is much stronger. Resolution of this fact, using a theoretical model, reveals that the attraction between DNA and the charges inside the barrel of the pore is the most dominant factor in determining the translocation speed and not merely the driving electrochemical potential gradient
HOXC4 homeoprotein efficiently expands human hematopoietic stem cells and triggers similar molecular alterations as HOXB4
International audienc
NK-cell culture procedure of hESC-derived hematopoietic precursor cells.
<p>Schematic representation of the three steps of NK-cells differentiation from hESCs. hEBs derived from the H1 hESC cell line were dissociated then co-cultured with MS-5/SP-HOXB4 cells or MS-5/EGFP cells as control during 2 weeks. Then, the cells derived from the first step of co-culture were submitted to a second step of 3-week co-culture with unmodified MS-5 cells, in permissive conditions for NK-cell differentiation in presence of SCF, IL-2 and IL-15. NK-cell culture differentiation was conducted directly with un-co-cultured hEB-derived cells as control. (B) Analysis of the presence of the HOXB4 protein within hEB-derived cells co-cultured with either MS-5/SP-HOXB4 (dark line) or MS-5/EGFP (dotted line) stromal cell lines. Data are from one experiment out of two. Gray histogram corresponds to isotypic control. Abbreviations : cy, cytoplasmic.</p
Analysis of NK differentiation potential and NK progenitor cell expansion mediated by HOXB4.
<p>(A) Percentages of NK cells (CD56<sup>+</sup>CD3<sup>â</sup>CD19<sup>â</sup>) among nucleated cells collected at the end of 5 weeks of co-culture. Cells derived from the 2 weeks primary co-cultures with MS-5/SP-HOXB4 or MS-5/EGFP were then plated on unmodified MS-5 cells in conditions known to promote NK-cell differentiation and maintained during three weeks. At the end of the culture period, cells were analyzed by FACS for the expression of CD56 and CD3/CD19 markers. Un-co-cultured hEB cells were directly cultured under NK-cell differentiation conditions for 3 weeks (nâ=â5, *<i>p</i><0.05, **<i>p</i><0.01). (B) Fold increase of total NK cells. NK cells were derived from total cells isolated from the primary 2-week co-cultures of hEB-derived cells with either MS-5/SP-HOXB4 or MS-5/EGFP control and then cultured under NK-cell differentiation condition for three weeks. NK cells were then numbered. Bars represent fold amplifications relative to day-0 control (un-co-cultured hEBs) (designated as 100%) (nâ=â5, *<i>p</i><0,05).</p
BiomĂ©dicaments dans le psoriasis de lâenfant de moins de 12 ans. Cohorte rĂ©trospective Franco-Italienne
International audienceIntroductionLâutilisation des biomĂ©dicaments est indiquĂ©e dans les formes modĂ©rĂ©es Ă sĂ©vĂšres du psoriasis chez lâadulte et lâenfant. Jusquâen 2020, 2 biomĂ©dicaments Ă©taient autorisĂ©s avant 12 ans, lâadalimumab (ADA) et lâĂ©tanercept (ETC), 3 autres molĂ©cules devraient ĂȘtre disponibles en 2021 (AMM europĂ©enne en 2020) : lâustĂ©kinumab (UST), le sĂ©cukinumab et lâixĂ©kizumab. Cette population des enfants de moins de 12 ans est sous-reprĂ©sentĂ©e dans les essais thĂ©rapeutiques, sans analyse dĂ©diĂ©e le plus souvent, ainsi que dans les cohortes rĂ©trospectives. Une premiĂšre Ă©tude, lâĂ©tude « BiPe » menĂ©e en France sur 134 enfants et 184 lignes de traitements Ă©tudiait tous les enfants dâĂąge infĂ©rieur Ă 18 ans. Moins dâun tiers des enfants avait moins de 12 ans. Lâobjectif de lâĂ©tude « BiPe Jr » Ă©taient dâĂ©valuer le taux de maintien et la tolĂ©rance des biomĂ©dicaments dans le psoriasis des enfants de moins de 12 ans.MatĂ©riel et mĂ©thodesĂtude multicentrique franco-italienne, rĂ©trospective, par appel Ă cas (SFDP, GrPso, SIDerP) dâenfants atteints de psoriasis ayant reçu au moins une injection de biothĂ©rapies, ayant ou non lâAMM, avant lâĂąge de 12 ans. Etaient exclus les enfants traitĂ©s dans le cadre dâun essai thĂ©rapeutique et lâindication rhumatisme psoriasique. Les donnĂ©es sociodĂ©mographiques, cliniques et thĂ©rapeutiques ont Ă©tĂ© recueillies.RĂ©sultatsSoixante-quinze enfants (filles, n = 45 (58,1 %)) ont Ă©tĂ© inclus pour un total de 97 lignes de biomĂ©dicaments (ADA (n = 46), ETC (n = 35), UST (n = 11), anakinra (n = 2), infliximab (n = 2) et sĂ©cukinumab (n = 1), avec 1 Ă 6 lignes initiĂ©es avant 12 ans. Quinze enfants (25,8 %) Ă©taient en surpoids, 25 (33,8 %) avaient un antĂ©cĂ©dent familial de psoriasis. La forme « psoriasis en plaques » Ă©tait la plus frĂ©quente (n = 43, 57,3 %), suivie par la forme palmoplantaire (n = 16, 21,3 %) ; 5 (7,6 %) avaient un rhumatisme et 24 (36,4 %) une onychopathie psoriasique. Le PGA moyen Ă lâinitiation Ă©tait de 3,8 ± 0,9 et le PASI de 13,7 ± 9,4. LâĂąge moyen au dĂ©but de la biothĂ©rapie Ă©tait de 9,0 ± 0,6 ans. Une tendance Ă un meilleur maintien de lâUST et de lâADA versus lâETC Ă©tait observĂ©e (p = 0,12) ; trente-quatre enfants ont arrĂȘtĂ© leur biomĂ©dicament pour perte dâefficacitĂ© (n = 19), inefficacitĂ© primaire (n = 8), choix de la famille (n = 4) et effets indĂ©sirables (n = 3). Six Ă©vĂ©nements indĂ©sirables graves (EIG) ont Ă©tĂ© rapportĂ©s et sont dĂ©taillĂ©s.DiscussionCette 1re Ă©tude de large ampleur, en vie courante, menĂ©e chez lâenfant de moins de 12 ans complĂšte les rĂ©sultats de lâĂ©tude BiPe menĂ©e chez les enfants et adolescents psoriasiques. La comparaison des taux de maintien des biomĂ©dicaments nâa pas mis en Ă©vidence de diffĂ©rence significative malgrĂ© une discrĂšte tendance Ă un meilleur maintien de lâUST et de lâADA, comme dĂ©jĂ observĂ© chez les plus grands. Les EIG mis en Ă©vidence Ă©taient rares mais rappellent la nĂ©cessitĂ© dâune vigilance accrue du risque infectieux