Differentiation of nonhuman primate pluripotent stem cells into functional keratinocytes.

Background: Epidermal grafting using cells derived from pluripotent stem cells will change the face of this side of regenerative cutaneous medicine. To date, the safety of the graft would be the major unmet deal in order to implement long-term skin grafting. In this context, experiments on large animals appear unavoidable to assess this question and possible rejection.

DNA replication timing alterations identify common markers between distinct progeroid diseases.

Progeroid syndromes are rare genetic disorders that phenotypically resemble natural aging. Different causal mutations have been identified, but no molecular alterations have been identified that are in common to these diseases. DNA replication timing (RT) is a robust cell type-specific epigenetic feature highly conserved in the same cell types from different individuals but altered in disease.

[Prerequisite for hematopoietic cellular therapy programs to set up chimeric antigen receptor T-cell therapy (CAR T-cells): Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)].

CAR T-cells are autologous or allogeneic human lymphocytes that are genetically engineered to express a chimeric antigen receptor targeting an antigen expressed on tumor cells such as CD19. CAR T-cells represent a new class of medicinal products, and belong to the broad category of Advanced Therapy Medicinal Products (ATMPs), as defined by EC Regulation 2007-1394. Specifically, they are categorized as gene therapy medicinal products.

Septins restrict inflammation and protect zebrafish larvae from Shigella infection.

Shigella flexneri, a Gram-negative enteroinvasive pathogen, causes inflammatory destruction of the human intestinal epithelium. Infection by S. flexneri has been well-studied in vitro and is a paradigm for bacterial interactions with the host immune system.

Comprehensive Proteomic Analysis of Human Erythropoiesis.

Mass spectrometry-based proteomics now enables the absolute quantification of thousands of proteins in individual cell types. We used this technology to analyze the dynamic proteome changes occurring during human erythropoiesis. We quantified the absolute expression of 6,130 proteins during erythroid differentiation from late burst-forming units-erythroid (BFU-Es) to orthochromatic erythroblasts.

Triggering the TCR Developmental Checkpoint Activates a Therapeutically Targetable Tumor Suppressive Pathway in T-cell Leukemia.

Unlabelled: Cancer onset and progression involves the accumulation of multiple oncogenic hits, which are thought to dominate or bypass the physiologic regulatory mechanisms in tissue development and homeostasis. We demonstrate in T-cell acute lymphoblastic leukemia (T-ALL) that, irrespective of the complex oncogenic abnormalities underlying tumor progression, experimentally induced, persistent T-cell receptor (TCR) signaling has antileukemic properties and enforces a molecular program resembling thymic negative selection, a major developmental event in normal T-cell development. Using mouse models of T-ALL, we show that induction of TCR signaling by high-affinity self-peptide/MHC or treatment with monoclonal antibodies to the CD3ε chain (anti-CD3) causes massive leukemic cell death.

Axial stretch-dependent cation entry in dystrophic cardiomyopathy: Involvement of several TRPs channels.

In Duchenne muscular dystrophy (DMD), deficiency of the cytoskeletal protein dystrophin leads to well-described defects in skeletal muscle but also to dilated cardiomyopathy (DCM). In cardiac cells, the subsarcolemmal localization of dystrophin is thought to protect the membrane from mechanical stress. The dystrophin deficiency leads to membrane instability and a high stress-induced Ca(2+) influx due to dysregulation of sarcolemmal channels such as stretch-activated channels (SACs).

Impact of collection conditions on the metabolite content of human urine samples as analyzed by liquid chromatography coupled to mass spectrometry and nuclear magnetic resonance spectroscopy.

There is a lack of comprehensive studies documenting the impact of sample collection conditions on metabolic composition of human urine. To address this issue, two experiments were performed at a 3-month interval, in which midstream urine samples from healthy individuals were collected, pooled, divided into several aliquots and kept under specific conditions (room temperature, 4 °C, with or without preservative) up to 72 h before storage at -80 °C. Samples were analyzed by high-performance liquid chromatography coupled to high-resolution mass spectrometry and bacterial contamination was monitored by turbidimetry.

In vitro modeling of hyperpigmentation associated to neurofibromatosis type 1 using melanocytes derived from human embryonic stem cells.

"Café-au-lait" macules (CALMs) and overall skin hyperpigmentation are early hallmarks of neurofibromatosis type 1 (NF1). One of the most frequent monogenic diseases, NF1 has subsequently been characterized with numerous benign Schwann cell-derived tumors. It is well established that neurofibromin, the NF1 gene product, is an antioncogene that down-regulates the RAS oncogene.

Comparison Between Several Integrase-defective Lentiviral Vectors Reveals Increased Integration of an HIV Vector Bearing a D167H Mutant.

HIV-1 derived vectors are among the most efficient for gene transduction in mammalian tissues. As the parent virus, they carry out vector genome insertion into the host cell chromatin. Consequently, their preferential integration in transcribed genes raises several conceptual and safety issues.

Use of Shigella flexneri to study autophagy-cytoskeleton interactions.

Shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote its motility and dissemination. New work has shown that proteins involved in actin-based motility are also linked to autophagy, an intracellular degradation process crucial for cell autonomous immunity. Strikingly, host cells may prevent actin-based motility of S.

Annotation of the human serum metabolome by coupling three liquid chromatography methods to high-resolution mass spectrometry.

This work aims at evaluating the relevance and versatility of liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) for performing a qualitative and comprehensive study of the human serum metabolome. To this end, three different chromatographic systems based on a reversed phase (RP), hydrophilic interaction chromatography (HILIC) and a pentafluorophenylpropyl (PFPP) stationary phase were used, with detection in both positive and negative electrospray modes. LC/HRMS platforms were first assessed for their ability to detect, retain and separate 657 metabolite standards representative of the chemical families occurring in biological fluids.

Induced pluripotent stem cells reveal functional differences between drugs currently investigated in patients with hutchinson-gilford progeria syndrome.

Hutchinson-Gilford progeria syndrome is a rare congenital disease characterized by premature aging in children. Identification of the mutation and related molecular mechanisms has rapidly led to independent clinical trials testing different marketed drugs with a preclinically documented impact on those mechanisms. However, the extensive functional effects of those drugs remain essentially unexplored.

Pluripotent stem cells as a model to study non-coding RNAs function in human neurogenesis.

As fine regulators of gene expression, non-coding RNAs, and more particularly micro-RNAs (miRNAs), have emerged as key players in the development of the nervous system. In vivo experiments manipulating miRNAs expression as neurogenesis proceeds are very challenging in the mammalian embryo and totally impossible in the human. Human pluripotent stem cells (hPSCs), from embryonic origin (hESCs) or induced from adult somatic cells (iPSCs), represent an opportunity to study the role of miRNAs in the earliest steps of human neurogenesis in both physiological and pathological contexts.

Functional melanocytes derived from human pluripotent stem cells engraft into pluristratified epidermis.

Melanocytes are essential for skin homeostasis and protection, and their defects in humans lead to a wide array of diseases that are potentially extremely severe. To date, the analysis of molecular mechanisms and the function of human melanocytes have been limited because of the difficulties in accessing large numbers of cells with the specific phenotypes. This issue can now be addressed via a differentiation protocol that allows melanocytes to be obtained from pluripotent stem cell lines, either induced or of embryonic origin, based on the use of moderate concentrations of a single cytokine, bone morphogenic protein 4.

Neutrophil role in in vivo anti-lymphoma activity of rituximab: FCGR3B-NA1/NA2 polymorphism does not influence response and survival after rituximab treatment.

Background: Neutrophils could play an important role in in vivo rituximab anti-lymphoma activity. FcgammaRIIIb is expressed only by neutrophils and FcgammaRIIIb-neutrophil antigen (NA)1/NA2 polymorphism influenced phagocytosis of immunoglobulin G1-opsonized particles. We formulated the hypothesis that if neutrophils are critical cells for in vivo rituximab activity, FcgammaRIIIb-NA1/NA2 polymorphism could influence the response to rituximab.

Specific dose-response effects of TGF-beta1 on developmentally distinct hematopoietic stem/progenitor cells from human umbilical cord blood.

Introduction: Transforming Growth Factor-beta1 is known to maintain primitive human hematopoietic stem/progenitor cells in a quiescent state. However, its specific role in the control of distinct progenitor cell types needs to be further elucidated. In this study, we have investigated the dose-response effect of TGF-beta1 on progenitors ranging from primitive high proliferative potential (HPP)-Mix, -GM or -BFU-E to later BFU-E, CFU-G or CFU-M.

The high proliferative potential-quiescent (HPP-Q) cell assay allows an optimized evaluation of gene transfer efficiency into primitive hematopoietic stem/progenitor cells.

Various protocols have been described to optimize gene transfer into hematopoietic cells. However, most of these methods do not specify whether they are associated with an improved transduction of the more primitive stem/progenitor cells, the best candidates for long-term engraftment. The majority of these primitive cells remains in quiescence because of the negative control of TGF-beta1, effective on these cells at low concentrations (10 pg/ml).

Transforming growth factor-beta: pleiotropic role in the regulation of hematopoiesis.

Hematopoiesis is a remarkable cell-renewal process that leads to the continuous generation of large numbers of multiple mature cell types, starting from a relatively small stem cell compartment. A highly complex but efficient regulatory network is necessary to tightly control this production and to maintain the hematopoietic tissue in homeostasis. During the last 3 decades, constantly growing numbers of molecules involved in this regulation have been identified.

p21(cip1) mRNA is controlled by endogenous transforming growth factor-beta1 in quiescent human hematopoietic stem/progenitor cells.

Transforming growth factor-beta1 (TGF-beta1) has been described as an efficient growth inhibitor that maintains the CD34(+) hematopoietic progenitor cells in quiescence. The concept of high proliferative potential-quiescent cells or HPP-Q cells has been introduced as a working model to study the effect of TGF-beta1 in maintaining the reversible quiescence of the more primitive hematopoietic stem cell compartment. HPP-Q cells are primitive quiescent stem/progenitor cells on which TGF-beta1 has downmodulated the cytokine receptors.

Release from quiescence of primitive human hematopoietic stem/progenitor cells by blocking their cell-surface TGF-beta type II receptor in a short-term in vitro assay.

Genetic alterations of the signaling cascade of transforming growth factor-beta (TGF-beta) are often associated with neoplastic transformation of primitive cells. This demonstrates the key role for this pleiotropic factor in the control of quiescence and cell proliferation in vivo. In the high proliferative potential-quiescent cell (HPP-Q) in vitro assay, the use of TGF-beta1 blocking antibodies (anti-TGF-beta1) allows the detection within two to three weeks of primitive hematopoietic cells called HPP-Q, which otherwise would not grow.

Large-volume leukapheresis procedure for peripheral blood progenitor cell collection in children weighing 15 kg or less: efficacy and safety evaluation.

Background: We update our experience on large-volume leukapheresis (LVL) in very small patients with malignancies. LVLs were performed with the aim of reducing the psychological impact of leukaphereses by reducing the number of procedures while collecting large numbers of cells.

Procedure: Seventeen LVLs were performed using a Cobe Spectra separator in 14 patients weighing < or = 15 kg.