Construction of The Measurement Scale of the Audit Committee Diligence: The Perception of Tunisian Internal Auditors

This paper aims at measuring scales of the audit committee diligence for audit committees or for other governance organ concerned with the audit committee diligence. The conception and the validation of this measurement scales were done on the Tunisian ground. To construct a measure of audit committee diligence, we adopted the Churchil

Defective B-cell proliferation and maintenance of long-term memory in patients with chronic granulomatous disease

Background: Chronic granulomatous disease (CGD) is a primary immune deficiency characterized by a defect in reactive oxygen species production. Although the effect of CGD mainly reflects on the phagocytic compartment, B-cell responses are also impaired in patients with CGD. Objective: We sought to investigate how defective gp91phox expression in patients with CGD and CGD carriers might affect the B-cell compartment and maintenance of long-term memory. Methods: We studied the B-cell compartment of patients with CGD in terms of phenotype and ability to produce reactive oxygen species and proliferate on stimuli differently directed to the B-cell receptor and Toll-like receptor 9. We further studied their capacity to maintain long-term memory by measuring cellular and serologic responses to measles. Results: We show that the memory B-cell compartment is impaired among patients with CGD, as indicated by reduced total (CD191CD271) and resting (CD191CD271CD211) memory B cells in parallel to increased naive (CD191CD272IgD1) B-cell frequencies. Data on CGD carriers reveal that such alterations are related to gp91phox expression. Moreover, proliferative capabilities of B cells on selective in vitro stimulation of B-cell receptor or Toll-like receptor 9 pathways were reduced in patients with CGD compared with those seen in age-matched healthy control subjects. Significantly lower measles-specific antibody levels and antibody-secreting cell numbers were also observed, indicating a poor ability to maintain long-term memory in these patients. Conclusion: Altogether, our data suggest that patients with CGD present a defective B-cell compartment in terms of frequencies of memory B cells, response to in vitro stimulation, and maintenance of long-term antigen-specific memory

Xeno-Free and Defined Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells Functionally Integrate in a Large-Eyed Preclinical Model

SummaryHuman embryonic stem cell (hESC)-derived retinal pigment epithelial (RPE) cells could replace lost tissue in geographic atrophy (GA) but efficacy has yet to be demonstrated in a large-eyed model. Also, production of hESC-RPE has not yet been achieved in a xeno-free and defined manner, which is critical for clinical compliance and reduced immunogenicity. Here we describe an effective differentiation methodology using human laminin-521 matrix with xeno-free and defined medium. Differentiated cells exhibited characteristics of native RPE including morphology, pigmentation, marker expression, monolayer integrity, and polarization together with phagocytic activity. Furthermore, we established a large-eyed GA model that allowed in vivo imaging of hESC-RPE and host retina. Cells transplanted in suspension showed long-term integration and formed polarized monolayers exhibiting phagocytic and photoreceptor rescue capacity. We have developed a xeno-free and defined hESC-RPE differentiation method and present evidence of functional integration of clinically compliant hESC-RPE in a large-eyed disease model

Soluble HIV-1 Env trimers in adjuvant elicit potent and diverse functional B cell responses in primates

Broadly neutralizing antibodies (bNAbs) against the HIV-1 envelope glycoproteins (Envs) have proven difficult to elicit by immunization. Therefore, to identify effective Env neutralization targets, efforts are underway to define the specificities of bNAbs in chronically infected individuals. For a prophylactic vaccine, it is equally important to define the immunogenic properties of the heavily glycosylated Env in healthy primates devoid of confounding HIV-induced pathogenic factors. We used rhesus macaques to investigate the magnitude and kinetics of B cell responses stimulated by Env trimers in adjuvant. Robust Env-specific memory B cell responses and high titers of circulating antibodies developed after trimer inoculation. Subsequent immunizations resulted in significant expansion of Env-specific IgG-producing plasma cell populations and circulating Abs that displayed increasing avidity and neutralization capacity. The neutralizing activity elicited with the regimen used was, in most aspects, superior to that elicited by a regimen based on monomeric Env immunization in humans. Despite the potency and breadth of the trimer-elicited response, protection against heterologous rectal simian-HIV (SHIV) challenge was modest, illustrating the challenge of eliciting sufficient titers of cross-reactive protective NAbs in mucosal sites. These data provide important information for the design and evaluation of vaccines aimed at stimulating protective HIV-1 immune responses in humans

Core binding factors are necessary for natural killer cell development, and cooperate with Notch signaling during T cell specification

CBF{beta} is the non-DNA binding subunit of the core binding factors (CBFs). Mice with reduced CBF{beta} levels display profound, early defects in T but not B cell development. Here we show that CBF{beta} is also required at very early stages of natural killer (NK) cell development. We also demonstrate that T cell development aborts during specification, as the expression of Gata3 and Tcf7, which encode key regulators of T lineage specification, is substantially reduced, as are functional thymic progenitors. Constitutively active Notch or IL-7 signaling cannot restore T cell expansion or differentiation of CBF{beta} insufficient cells, nor can overexpression of Runx1 or CBF{beta} overcome a lack of Notch signaling. Therefore the ability of the prethymic cell to respond appropriately to Notch is dependent on CBF{beta}, and both signals converge to activate the T cell developmental program

Transforming Growth Factor-β3 Regulates Adipocyte Number in Subcutaneous White Adipose Tissue.

White adipose tissue (WAT) mass is determined by adipocyte size and number. While adipocytes are continuously turned over, the mechanisms controlling fat cell number in WAT upon weight changes are unclear. Herein, prospective studies of human subcutaneous WAT demonstrate that weight gain increases both adipocyte size and number, but the latter remains unaltered after weight loss. Transcriptome analyses associate changes in adipocyte number with the expression of 79 genes. This gene set is enriched for growth factors, out of which one, transforming growth factor-β3 (TGFβ3), stimulates adipocyte progenitor proliferation, resulting in a higher number of cells undergoing differentiation in vitro. The relevance of these observations was corroborated in vivo where Tgfb3+/- mice, in comparison with wild-type littermates, display lower subcutaneous adipocyte progenitor proliferation, WAT hypertrophy, and glucose intolerance. TGFβ3 is therefore a regulator of subcutaneous adipocyte number and may link WAT morphology to glucose metabolism

Characterization of Stem-Like Cells in Mucoepidermoid Tracheal Paediatric Tumor

Stem cells contribute to regeneration of tissues and organs. Cells with stem cell-like properties have been identified in tumors from a variety of origins, but to our knowledge there are yet no reports on tumor-related stem cells in the human upper respiratory tract. In the present study, we show that a tracheal mucoepidermoid tumor biopsy obtained from a 6 year-old patient contained a subpopulation of cells with morphology, clonogenicity and surface markers that overlapped with bone marrow mesenchymal stromal cells (BM-MSCs). These cells, designated as MEi (mesenchymal stem cell-like mucoepidermoid tumor) cells, could be differentiated towards mesenchymal lineages both with and without induction, and formed spheroids in vitro. The MEi cells shared several multipotent characteristics with BM-MSCs. However, they displayed differences to BM-MSCs in growth kinectics and gene expression profiles relating to cancer pathways and tube development. Despite this, the MEi cells did not possess in vivo tumor-initiating capacity, as proven by the absence of growth in situ after localized injection in immunocompromised mice. Our results provide an initial characterization of benign tracheal cancer-derived niche cells. We believe that this report could be of importance to further understand tracheal cancer initiation and progression as well as therapeutic development

Comprehensive Cell Surface Protein Profiling Identifies Specific Markers of Human Naive and Primed Pluripotent States

Human pluripotent stem cells (PSCs) exist in naive and primed states and provide important models to investigate the earliest stages of human development. Naive cells can be obtained through primed-to-naive resetting, but there are no reliable methods to prospectively isolate unmodified naive cells during this process. Here we report comprehensive profiling of cell surface proteins by flow cytometry in naive and primed human PSCs. Several naive-specific, but not primed-specific, proteins were also expressed by pluripotent cells in the human preimplantation embryo. The upregulation of naive-specific cell surface proteins during primed-to-naive resetting enabled the isolation and characterization of live naive cells and intermediate cell populations. This analysis revealed distinct transcriptional and X chromosome inactivation changes associated with the early and late stages of naive cell formation. Thus, identification of state-specific proteins provides a robust set of molecular markers to define the human PSC state and allows new insights into the molecular events leading to naive cell resetting.Imaging was performed at the Live Cell Imaging Facility/Nikon Center of Excellence, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden, supported by grants from the Knut and Alice Wallenberg Foundation, the Swedish Research Council, the Centre for Innovative Medicine, and the Jonasson donation to the School of Technology and Health, Royal Institute of Technology, Sweden. We would like to acknowledge the MedH Flow Cytometry facility at Karolinska Institutet, supported by grants from Karolinska Institutet and the Stockholm County Council. We thank Céline Vallot and Claire Rougeulle at the Université Paris Diderot for providing X chromosome SNP coordinates. We are grateful to Rudolph Jaenisch at the Whitehead Institute for Biomedical Research for providing WIBR3 cells and Austin Smith at the WT–MRC Cambridge Stem Cell Institute for providing H9 NK2 and FiPS cells. We thank all couples who donated embryos to this study. S.P., A.P.R., J.P.S., and F.L. are supported by grants from the Swedish Research Council (2013-2570), Ragnar Söderberg Foundation (M67/13), Swedish Foundation for Strategic Research (ICA-5), Knut and Alice Wallenberg Foundation (4-1205/2016 and 4-148/2017), and Centre for Innovative Medicine and by a Lau fellowship. R.W. is an ISAC Shared Resource Laboratory Emerging Leader. A.J.C. is supported by an MRC DTG Studentship (MR/J003808/1). P.J.R.G. is supported by the Wellcome Trust (WT093736) and BBSRC (BBS/ E/B/000C0402)