Ibtissam Youlyouz Marfak

Dr. Ibtissam Youlyouz Marfak


Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 November 2011 in Blood
Verified
Journal Article
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PNPaquita Nurden
Paquita Nurden
NDNajet Debili
Najet Debili
ICIsabelle Coupry
Isabelle Coupry
MBMarijke Bryckaert
Marijke Bryckaert
IMIbtissam Youlyouz Marfak
Ibtissam Youlyouz Marfak
CGCyril Goizet
Cyril Goizet
Filaminopathies A caused by mutations in the X-linked FLNA gene are responsible for a wide spectrum of rare diseases including 2 main phenotypes, the X-linked dominant form of periventricular nodular heterotopia (FLNA-PVNH) and the otopalatodigital syndrome spectrum of disorders. In platelets, filamin A (FLNa) tethers the principal receptors ensuring the platelet–vessel wall interaction, glycoprotein Ibα and integrin αIIbβ3, to the underlying cytoskeleton. Hemorrhage, coagulopathy, and thrombocytopenia are mentioned in several reports on patients with FLNA-PVNH. Abnormal platelet morphology in 2 patients with FLNA-PVNH prompted us to examine a third patient with similar platelet morphology previously diagnosed with immunologic thrombocytopenic purpura. Her enlarged platelets showed signs of FLNa degradation in Western blotting, and a heterozygous missense mutation in FLNA was detected. An irregular distribution of FLNa within the total platelet population was shown by confocal microscopy for all 3 patients. In vitro megakaryocyte cultures showed an abnormal differentiation, including an irregular distribution of FLNa with a frayed aspect, the presence of enlarged α-granules, and an abnormal fragmentation of the cytoplasm. Mutations in FLNA may represent an unrecognized cause of macrothrombocytopenia with an altered platelet production and a modified platelet–vessel wall interaction.

8 August 2005 in Oncogene
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Journal Article
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Rosa A. Gonzalez-PoloRosa A. Gonzalez-Polo
Rosa A. Gonzalez-Polo
GCGabrielle Carvalho
Gabrielle Carvalho
TBThorsten Braun
Thorsten Braun
DDDidier Decaudin
Didier Decaudin
CFClaire Fabre
Claire Fabre
Guido KroemerGuido Kroemer
Guido Kroemer

2 August 2022 in International Journal of Women's Health
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Journal Article
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ABAmal Boutib
Amal Boutib
SCSamia Chergaoui
Samia Chergaoui
AMAbdelghafour Marfak
Abdelghafour Marfak
AHAbderraouf Hilali
Abderraouf Hilali
IMIbtissam Youlyouz Marfak
Ibtissam Youlyouz Marfak
Purpose: Health-related quality of life (HRQoL) has emerged as a key concern in patient care. It has become one of the major objectives of clinical trials. Our study aims to describe the quality of life (QoL) during uncomplicated pregnancy and to assess its associated factors. Patients and Methods: The search of articles was carried out using the online database of PUBMED and Web of Science with a limit of time between 2011 and 2021. Data were retrieved by two independent reviewers. Results: 721 publications responding to keywords were identified, of which 73 articles on the topic were selected. The main countries that have published on this subject are Australia (n = 10) and China (n = 7). Twenty-three articles deal with QoL for pathological pregnancies. All the pathologies studied have a negative impact on the HRQoL of pregnant women, and its improvement depends on the type of treatment. Obesity, low back, and pelvic girdle pain, and hyperemesis gravidarum were the frequent pathologies during pregnancy. Socio-demographic characteristics related to improved well-being (favorable economic status, social support). Similarly, better sleep quality and moderate physical exercise were linked to an increased QoL. Physical and psychological factors were associated with a lower QoL. Conclusion: The HRQoL refers to patients’ subjective evaluation of physical, mental, and social components of well-being. Optimizing the QoL during pregnancy necessitates a deeper understanding of their issues as well as counseling which provides support wherever needed.

1 April 2010 in Blood
Verified
Journal Article
Closed access
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PNPaquita Nurden
Paquita Nurden
GGGiuliana Gobbi
Giuliana Gobbi
ANAlan Nurden
Alan Nurden
JEJocelyne Enouf
Jocelyne Enouf
IMIbtissam Youlyouz Marfak
Ibtissam Youlyouz Marfak
AFAugusto B. Federici
Augusto B. Federici
Von Willebrand factor (VWF) is an essential mediator of platelet adhesion to the vessel wall, but little is known about its role in megakaryocytopoiesis. VWF and its platelet receptor, glycoprotein Ibα (GPIbα), are both expressed during megakaryocyte (MK) maturation. This study was designed to evaluate whether the enhanced VWF-GPIbα interactions typical of patients with von Willebrand disease type 2B (VWD2B) modify platelet production. Platelets from 9 patients with VWD2B with 7 different gain-of-function mutations were examined by electron microscopy (EM) and immunofluorescence labeling. For the patients with VWD2B, EM characteristically showed variable numbers of structurally abnormal giant platelets, sometimes in agglutinates. Cultures of MKs from controls performed with or without purified VWF confirmed a positive influence of VWF on platelet production with specific inhibition by an antibody blocking VWF binding to GPIbα. VWD2B MK cultures examined by EM showed a disorganized demarcation membrane system and abnormal granule distribution. They produced platelets with structural abnormalities typical of VWD2B. Confocal examination of MK revealed limited extension of pseudopods with few large proplatelets. These results confirm that megakaryocytopoiesis is modified by the enhanced VWF-GPIbα interactions. These data obtained for controls and patients with VWD2B suggest a novel regulatory role of VWF-GPIbα interactions in platelet production.

1 March 2006 in Blood
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Journal Article
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CCChristophe Le Clorennec
Christophe Le Clorennec
IMIbtissam Youlyouz Marfak
Ibtissam Youlyouz Marfak
EAEric Adriaenssens
Eric Adriaenssens
JCJean Coll
Jean Coll
GBGeorg W. Bornkamm
Georg W. Bornkamm
JFJean Feuillard
Jean Feuillard
Epstein-Barr virus (EBV) induces CD95 expression and the CD95 gene (FAS) is regulated by NF-κB, STAT1, and/or p53. To understand the contribution of these factors in the regulation of CD95 by EBV in lymphoblastoid cell lines (LCLs), we cloned dominant-active IκBα, active (STAT1α) and inactive (STAT1β) forms of STAT1, p53, a dominant-negative mutant of LMP1, and wild-type LMP1 into a novel double-inducible episomal vector, pRT-1. These plasmids were stably transfected either into wild-type LCLs or EREB2-5 cells, an LCL with an estrogen-regulatable EBNA2 protein. Inhibition of LMP1 signaling decreased expression of CD95, whereas overexpression of LMP1 markedly increased it. Induction of the latency III program in EREB2-5 cells correlated with activation of NF-κB, STAT1, and p53. CD95 expression was regulated by these 3 transcriptional systems. STAT1 and p53 activation were secondary to NF-κB activation. CD95 surface expression sensitized EBV-infected B cells to the induction of CD95-mediated apoptosis. In vitro inhibition of CD95-CD95 ligand interaction was found to reverse T-cell killing of EBV-infected B cells. Therefore, LMP1 activation of NF-κB sensitizes infected B cells to CD95-mediated apoptosis and renders EBV latency III–immortalized B cells susceptible to elimination by the immune system, contributing to the establishment of a host/virus equilibrium.

15 April 2005 in Journal of Virology
Verified
Journal Article
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INImen Najjar
Imen Najjar
FBFanny Baran-Marszak
Fanny Baran-Marszak
CCChristophe Le Clorennec
Christophe Le Clorennec
CLChristelle Laguillier
Christelle Laguillier
OSOlivier Schischmanoff
Olivier Schischmanoff
RFRemi Fagard
Remi Fagard
Constitutive activation of signal transducer and activator of transcription 1 (STAT1) is a distinctive feature of Epstein-Barr virus (EBV)-immortalized B cells (lymphoblastoid cell lines [LCLs]). The expression of STAT1 in these cells is modulated by the latent membrane protein 1 (LMP1), but the mechanism of STAT1 activation has remained unclear. We demonstrate that the tyrosine phosphorylation of STAT1 in LCLs results from an indirect pathway encompassing an NF-κB-dependent secretion of interferons (IFNs). The cell culture supernatant of LCLs induced tyrosine phosphorylation of STAT1 in cells with no constitutively activated STAT1. Moreover, removal of supernatant from LCLs was sufficient to decrease the phosphorylation of STAT1. Inhibition of NF-κB activity by different pharmacological inhibitors (i.e., parthenolide, MG132 and BAY 11-7082) and by overexpressed mutated IκBα prevented the activation of STAT1. To identify the factors involved, we performed macroarray cDNA profiling with or without inhibition of NF-κB. The expression of several cytokines was NF-κB dependent among those alpha and gamma IFNs (IFN-α and IFN-γ), known activators of STAT1. By real-time PCR and enzyme-linked immunosorbent assay we show that IFN-α and IFN-γ are expressed and released by LCLs in an NF-κB-dependent manner. Finally, the blocking of the IFN-α and IFN-γ by neutralizing antibodies led to the complete inhibition of tyrosine phosphorylation of STAT1. Taken together, our results clearly show that LMP1-induced tyrosine phosphorylation of STAT1 is almost exclusively due to the NF-κB-dependent secretion of IFNs. Whether this response, which is usually considered to be antiviral, is in fact required for the persistence of the virus remains to be elucidated.