87 results on '"Merhi R"'
Search Results
2. Association corticothérapie générale mini-pulse et méthotrexate pour la prise en charge du vitiligo
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Guyon, M., primary, Merhi, R., additional, Andreu, N., additional, Gey, A., additional, Desolneux, F. Ballanger, additional, Boniface, K., additional, and Seneschal, J., additional
- Published
- 2022
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3. Cyclosporine a prevents replicative senescence-related endothelial dysfunction, pro-thrombotic and pro-coagulant responses and mp shedding in primary coronary artery endothelial cells: VB03
- Author
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Abbas, M, Toti, F, Zobairi, F, Hamade, E, Merhi, R A, Schini-Kerth, V, and Morel, O
- Published
- 2014
4. KSHV-transformed primary effusion lymphoma cells induce a VEGF-dependent angiogenesis and establish functional gap junctions with endothelial cells
- Author
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Haddad, L, El Hajj, H, Abou-Merhi, R, Kfoury, Y, Mahieux, R, El-Sabban, M, and Bazarbachi, A
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- 2008
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5. PS-341 or a combination of arsenic trioxide and interferon-α inhibit growth and induce caspase-dependent apoptosis in KSHV/HHV-8-infected primary effusion lymphoma cells
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Abou-Merhi, R, Khoriaty, R, Arnoult, D, El Hajj, H, Dbouk, H, Munier, S, El-Sabban, M E, Hermine, O, Gessain, A, de Thé, H, Mahieux, R, and Bazarbachi, A
- Published
- 2007
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6. Efficacité et tolérance du méthotrexate dans le vitiligo : étude rétrospective, monocentrique
- Author
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Merhi, R., primary, Andreu, N., additional, Gey, A., additional, Ballanger-Désolneux, F., additional, Boniface, K., additional, and Seneschal, J., additional
- Published
- 2020
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7. Évolution fatale d’un syndrome de lyse tumorale sous double immunothérapie (anti-CTLA-4 et anti-PD1)
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Merhi, R., primary, Ducharme, O., additional, Pham-Ledard, A., additional, Beylot-Barry, M., additional, and Gérard, E., additional
- Published
- 2020
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8. Hyperéosinophilie associée au traitement par dupilumab dans la dermatite atopique modérée à sévère : étude rétrospective multicentrique du GREAT
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Marcant, P., primary, Balayé, P., additional, Merhi, R., additional, Seneschal, J., additional, Tauber, M., additional, Jendoubi, F., additional, Nosbaum, A., additional, Raison-Peyron, N., additional, Du-Thanh, A., additional, Lasek, A., additional, Ferrier le Bouedec, M.-C., additional, Tetart, F., additional, Valois, A., additional, Lefevre, G., additional, Barbarot, S., additional, Soria, A., additional, Jachiet, M., additional, and Staumont-Sallé, D., additional
- Published
- 2020
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9. Évaluation des scores objectifs du vitiligo : VASI, Face-VASI et VES à partir de clichés photographiques standardisés de patients atteints de vitiligo
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Merhi, R., primary, Canu, D., additional, Barnetche, T., additional, Andreu, N., additional, Duchez, E., additional, Rasolofo-Andriamiasy, S., additional, Gey, A., additional, Taieb, A., additional, and Seneschal, J., additional
- Published
- 2020
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10. Le mélanocyte : un acteur majeur dans la réponse inflammatoire épidermique induite par les lymphocytes T cutanés au cours du vitiligo
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Martins, C., primary, Drullion, C., additional, Migayron, L., additional, Jacquemin, C., additional, Rambert, J., additional, Merhi, R., additional, Taieb, A., additional, Reza Rezvani, H., additional, Seneschal, J., additional, and Boniface, K., additional
- Published
- 2020
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11. Enquête sur les pratiques et les connaissances des étudiants en médecine au Liban vis-à-vis de l’exposition au soleil
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Gerbaka, N.-E., primary, Merhi, R., additional, and Tabet, C., additional
- Published
- 2018
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12. L’ingénol mébutate est efficace contre les verrues récalcitrantes des patients immunodéprimés
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Mrad, M., primary, Merhi, R., additional, and Ayoub, N., additional
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- 2017
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13. Le carvédilol est efficace contre le syndrome du scrotum rouge
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Mrad, M., primary, Merhi, R., additional, and Ayoub, N., additional
- Published
- 2017
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14. Endothelial microparticles from ACS patients induce premature endothelial cells ageing and thrombogenicity: Role of the Ang II/ATIR/NADPH oxidase-mediated activation of MAPKs and PI3-kinase pathways
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Abbas, M., primary, Jesel, L., additional, Auger, C., additional, Amoura, L., additional, Messas, N., additional, Manin, G., additional, Rumig, C., additional, Leon-Gonzalez, A.J., additional, Ribeiro, T.P., additional, Silva, G., additional, Abou-Merhi, R., additional, Hamade, E., additional, Hecker, M., additional, Georg, Y., additional, Chakfe, N., additional, Ohlmann, P., additional, Schini-Kerth, V.B., additional, Toti, F., additional, and Morel, O., additional
- Published
- 2017
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15. L’insula, nouvelle cible de stimulation pour les douleurs neuropathiques ? Étude expérimentale (chat)
- Author
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Kobaïter-Maarrawi, S., primary, Merhi, R., additional, Azar, F., additional, Komboz, F., additional, Samaha, E., additional, and Maarrawi, J., additional
- Published
- 2017
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16. Dupilumab‐associated hypereosinophilia in patients treated for moderate‐to‐severe atopic dermatitis.
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Marcant, P., Balayé, P., Merhi, R., Jendoubi, F., Nosbaum, A., Raison‐Peyron, N., Du‐Thanh, A., Lasek, A., Ferrier le Bouedec, M.‐C., Tetart, F., Valois, A., Barbarot, S., Soria, A., Jachiet, M., and Staumont‐Sallé, D.
- Subjects
HYPEREOSINOPHILIC syndrome ,ATOPIC dermatitis ,DUPILUMAB - Abstract
Trials assessing dupilumab in atopic dermatitis (AD) showed transient eosinophilia in less than 2% of patients.1 The frequency of hypereosinophilia (HE), defined as eosinophil blood count (EBC) >=1500/mm SP 3 sp ,2 was higher (15.8%) in our previous real-life cohort of AD patients treated with dupilumab.3 Since symptomatic HE was reported in asthma trials, we aimed to assess the clinical impact of HE in AD patients receiving dupilumab. Dupilumab-associated hypereosinophilia in patients treated for moderate-to-severe atopic dermatitis Fifty-nine patients with HE were included among a total of 653 patients receiving dupilumab from 12 hospital centres (Table 1), allowing us to estimate a mean prevalence of HE under dupilumab of 9% {95% CI [7.0-11.6]}. [Extracted from the article]
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- 2021
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17. 225 - Endothelial microparticles from ACS patients induce premature endothelial cells ageing and thrombogenicity: Role of the Ang II/ATIR/NADPH oxidase-mediated activation of MAPKs and PI3-kinase pathways
- Author
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Abbas, M., Jesel, L., Auger, C., Amoura, L., Messas, N., Manin, G., Rumig, C., Leon-Gonzalez, A.J., Ribeiro, T.P., Silva, G., Abou-Merhi, R., Hamade, E., Hecker, M., Georg, Y., Chakfe, N., Ohlmann, P., Schini-Kerth, V.B., Toti, F., and Morel, O.
- Published
- 2017
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18. Effect of anti-mullerian hormone on Sertoli and Leydig cell functions in fetal and immature rats
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Rouiller-Fabre, Virginie, Carmona, S., Abou Merhi, R., Cate, R., Habert, René, Vigier, Brigitte, ProdInra, Migration, Communications Cellulaires et Différenciation (CCD), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA), Unité de biologie cellulaire et moléculaire, and Institut National de la Recherche Agronomique (INRA)
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[SDV] Life Sciences [q-bio] ,[SDV]Life Sciences [q-bio] ,AMH ,RAT ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 1998
19. Characterization of ovine SRY transcript and developmental expression of genes involved in sexual differentiation
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Emmanuel Payen, Pailhoux E, Abou Merhi R, Gianquinto L, Kirszenbaum M, Locatelli A, and Cotinot C
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Anti-Mullerian Hormone ,Male ,Aging ,Sex Determination Analysis ,Sex Differentiation ,Transcription, Genetic ,Molecular Sequence Data ,Gestational Age ,Polymerase Chain Reaction ,Embryonic and Fetal Development ,Mice ,Pregnancy ,Y Chromosome ,Testis ,Animals ,Gene Library ,Glycoproteins ,Mammals ,Sertoli Cells ,Sheep ,Base Sequence ,Ovary ,Gene Expression Regulation, Developmental ,Nuclear Proteins ,Growth Inhibitors ,Sex-Determining Region Y Protein ,DNA-Binding Proteins ,Testicular Hormones ,Female ,Transcription Factors - Abstract
In mammals, the presence of SRY, the sex-determining gene located on the Y chromosome is required to induce the gonadal anlage to differentiate as a testis, whereas its absence leads to the development of an ovary. We report here the characterization by 5' and 3' RACE analysis of several SRY transcripts which are expressed in the ovine male developing gonads. These transcripts were not detected in any other fetal tissues and were expressed only in the genital portion of the urogenital ridge. The temporal profile of SRY expression analyzed by RT-PCR suggests that in the sheep fetus the role of SRY is not limited to initiating Sertoli cell differentiation as in mice. Indeed, SRY transcripts persist after the full differentiation of the testis. In addition to SRY, other genes are known to be involved in mammalian sex determination: Wilms' tumor gene WT-1, steroidogenic factor gene Ftz-F1 (SF-1) and anti-Müllerian hormone (AMH). We investigated the expression patterns of these genes by RT-PCR during fetal development in sheep gonads. Concerning WT-1 and SF-1, our results are consistent with those described in mice where the earliest expression was detected before the sexual differentiation in both sexes. In male, the ontogenesis of AMH transcription corresponds to the seminiferous cords formation (30 dpc). In female, we have observed the presence of SF-1 transcripts from the undifferentiated stage until birth. In addition, P450 aromatase expression is detected from 30 dpc and is correlated with the presence of 17-beta estradiol in sheep ovary. These data reveal significant differences between rodent and ruminant models concerning the sex-determining pathway.
- Published
- 1996
20. KSHV-transformed primary effusion lymphoma cells induce a VEGF-dependent angiogenesis and establish functional gap junctions with endothelial cells
- Author
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Haddad, L, primary, El Hajj, H, additional, Abou-Merhi, R, additional, Kfoury, Y, additional, Mahieux, R, additional, El-Sabban, M, additional, and Bazarbachi, A, additional
- Published
- 2007
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21. R-161. Fluorescent in-situ hybridization (FISH) on abortion material for aneuploidy diagnosis
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F. Hachem, F. Aboujaoude, I. Aboujaoude, and Merhi R. Abou
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Reproductive Medicine ,Rehabilitation ,medicine ,Obstetrics and Gynecology ,%22">Fish ,Aneuploidy ,In situ hybridization ,Biology ,Abortion ,medicine.disease ,Fluorescence ,Molecular biology - Published
- 1999
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22. R-161. Fluorescent in-situ hybridization (FISH) on abortion material for aneuploidy diagnosis
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Aboujaoude, I., primary, Abou, Merhi R., additional, Hachem, F., additional, and Aboujaoude, F., additional
- Published
- 1999
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23. New analogues of 13-hydroxyocatdecadienoic acid and 12-hydroxyeicosatetraenoic acid block human blood platelet aggregation and cyclooxygenase-1 activity
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Hirz Taghreed, Khalaf Ali, El-Hachem Nehme, Mrad May F, Abdallah Hassan, Créminon Christophe, Grée René, Merhi Raghida Abou, Habib Aïda, Hachem Ali, and Hamade Eva
- Subjects
Cyclooxygenase-1 ,Anti-thrombotic ,Inhibitors ,Polyunsaturated fatty acid ,Thrombosis ,Chemistry ,QD1-999 - Abstract
Abstract Background Thromboxane A2 is derived from arachidonic acid through the action of cyclooxygenases and thromboxane synthase. It is mainly formed in blood platelets upon activation and plays an important role in aggregation. Aspirin is effective in reducing the incidence of complications following acute coronary syndrome and stroke. The anti-thrombotic effect of aspirin is obtained through the irreversible inhibition of cyclooxygenases. Analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid were shown previously to modulate platelet activation and to block thromboxane receptors. Results and discussion We synthesized 10 compounds based on the structures of analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid and evaluated their effect on platelet aggregation triggered by arachidonic acid. The structure activity relationship was evaluated. Five compounds showed a significant inhibition of platelet aggregation and highlighted the importance of the lipidic hydrophobic hydrocarbon chain and the phenol group. Their IC50 ranged from 7.5 ± 0.8 to 14.2 ± 5.7 μM (Mean ± S.E.M.). All five compounds decreased platelet aggregation and thromboxane synthesis in response to collagen whereas no modification of platelet aggregation in response to thromboxane receptor agonist, U46619, was observed. Using COS-7 cells overexpressing human cyclooxygenase-1, we showed that these compounds are specific inhibitors of cyclooxygenase-1 with IC50 ranging from 1.3 to 12 μM. Docking observation of human recombinant cyclooxygenase-1 supported a role of the phenol group in the fitting of cyclooxygenase-1, most likely related to hydrogen bonding with the Tyr 355 of cyclooxygenase-1. Conclusions In conclusion, the compounds we synthesized at first based on the structures of analogues of 12 lipoxygenase metabolites showed a role of the phenol group in the anti-platelet and anti-cyclooxygenase-1 activities. These compounds mediate their effects via blockade of cyclooxygenase-1.
- Published
- 2012
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24. Combination of Baricitinib and Phototherapy in Adults With Active Vitiligo: A Randomized Clinical Trial.
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Seneschal J, Guyon M, Merhi R, Mazereeuw-Hautier J, Andreu N, Cazenave S, Ezzedine K, Passeron T, and Boniface K
- Abstract
Importance: Vitiligo is a chronic autoimmune disorder leading to skin depigmentation and reduced quality of life (QOL). Patients with extensive and very active disease are the most difficult to treat., Objective: To assess the efficacy and adverse events of baricitinib combined with narrowband UV-B in adults with severe, active, nonsegmental vitiligo., Design, Setting, and Participants: This academic, multicenter, double-blind, noncomparative randomized clinical trial was conducted at 4 dermatology departments between July 2021 and April 2023 and included adult patients with extensive and active nonsegmental vitiligo. The study was designed to evaluate the effect of baricitinib plus narrowband UV-B based solely on the results from this experimental group. The placebo group was used as a calibration group. Data were analyzed from August to November 2023., Interventions: Participants were randomized 3:1 to baricitinib, 4 mg per day, or placebo for 36 weeks alone for the first 12 weeks and then in combination with narrowband UV-B twice a week from weeks 12 to 36., Main Outcomes and Measures: The primary outcome was mean percentage change in total Vitiligo Area Scoring Index (VASI) score from baseline to week 36 (baricitinib group). The prespecified aim of the study was to show that the reduction in the baricitinib plus narrowband UV-B was significantly greater than 42.9%, a repigmented surface threshold previously observed in patients treated with narrowband UV-B alone. Adverse events and secondary outcomes of change in disease activity and QOL were assessed. Post hoc analyses were additionally performed., Results: Of 49 included patients, 35 (71%) were female, and the median (IQR) age was 49.9 (38.4-59.8) years. A total of 37 patients were randomized to the baricitinib group and 12 to the placebo group. The mean change in total VASI at week 36 was -44.8% (95% CI, -58.4% to -31.3%) for the baricitinib group and -9.2% (95% CI, -27.7% to 24.7%) for the placebo group. This was not significantly greater than the sufficient repigmented surface threshold of 42.9%. Post hoc analyses showed a significant difference at week 36 for total VASI score in the baricitinib plus narrowband UV-B group compared with placebo plus narrowband UV-B (-44.8% vs -9.2%, respectively; P = .02). There was a greater improvement in disease activity and QOL in the baricitinib group vs placebo group and no significant difference in the number of adverse events., Conclusions and Relevance: This proof-of-concept randomized clinical trial confirmed the efficacy of baricitinib combined with narrowband UV-B in the treatment of patients with extensive and active vitiligo., Trial Registration: ClinicalTrials.gov Identifier: NCT04822584.
- Published
- 2025
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25. Resident memory T cells in nonlesional skin and healed lesions of patients with chronic inflammatory diseases: Appearances can be deceptive.
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Migayron L, Merhi R, Seneschal J, and Boniface K
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- Humans, Memory T Cells, Immunologic Memory, Autoimmunity, CD8-Positive T-Lymphocytes, Vitiligo
- Abstract
Tissue-resident memory T (T
RM ) cells serve as a first line of defense in peripheral tissues to protect the organism against foreign pathogens. However, autoreactive TRM cells are increasingly implicated in autoimmunity, as evidenced in chronic autoimmune and inflammatory skin conditions. This highlights the need to characterize their phenotype and understand their role for the purpose of targeting them specifically without affecting local immunity. To date, the investigation of TRM cells in human skin diseases has focused mainly on lesional tissues of patients. Accumulating evidence suggests that self-reactive TRM cells are still present in clinically healed lesions of patients and play a role in disease flares, but TRM cells also populate skin that is apparently normal. This review discusses the ontogeny of TRM cells in the skin as well as recent insights regarding the presence of self-reactive TRM cells in both clinically healed skin and nonlesional skin of patients with autoimmune and inflammatory skin conditions, with a particular focus on psoriasis, atopic dermatitis, and vitiligo., (Copyright © 2023 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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26. Evaluation of Facial Vitiligo Severity with a Mixed Clinical and Artificial Intelligence Approach.
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Hillmer D, Merhi R, Boniface K, Taieb A, Barnetche T, Seneschal J, and Hagedorn M
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- Humans, Artificial Intelligence, Algorithms, Severity of Illness Index, Vitiligo drug therapy, Physicians
- Abstract
Vitiligo is the most common depigmenting skin disorder. Given the ongoing development of new targeted therapies, it has become important to evaluate adequately the surface area involved. Assessment of vitiligo scores can be time consuming, with variations between investigators. Therefore, the aim of this study was to build an artificial intelligence system capable of assessing facial vitiligo severity. One hundred pictures of faces of patients with vitiligo were used to train and validate the artificial intelligence model. Sixty-nine additional pictures of facial vitiligo were then used as a final dataset. Three expert physicians scored the facial vitiligo on the same 69 pictures. Inter and intrarater performances were evaluated by comparing the scores between raters and artificial intelligence. Algorithm assessment achieved an accuracy of 93%. Overall, the scores reached a good agreement between vitiligo raters and the artificial intelligence model. Results demonstrate the potential of the model. It provides an objective evaluation of facial vitiligo and could become a complementary/alternative tool to human assessment in clinical practice and/or clinical research., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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27. The nucleolar protein GNL3 prevents resection of stalled replication forks.
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Lebdy R, Canut M, Patouillard J, Cadoret JC, Letessier A, Ammar J, Basbous J, Urbach S, Miotto B, Constantinou A, Abou Merhi R, and Ribeyre C
- Subjects
- Humans, Nuclear Proteins genetics, Nuclear Proteins metabolism, DNA Damage, DNA, DNA Replication, GTP-Binding Proteins genetics
- Abstract
Faithful DNA replication requires specific proteins that protect replication forks and so prevent the formation of DNA lesions that may damage the genome. Identification of new proteins involved in this process is essential to understand how DNA lesions accumulate in cancer cells and how they tolerate them. Here, we show that human GNL3/nucleostemin, a GTP-binding protein localized mostly in the nucleolus and highly expressed in cancer cells, prevents nuclease-dependent resection of nascent DNA in response to replication stress. We demonstrate that inhibiting origin firing reduces resection. This suggests that the heightened replication origin activation observed upon GNL3 depletion largely drives the observed DNA resection probably due to the exhaustion of the available RPA pool. We show that GNL3 and DNA replication initiation factor ORC2 interact in the nucleolus and that the concentration of GNL3 in the nucleolus is required to limit DNA resection. We propose that the control of origin firing by GNL3 through the sequestration of ORC2 in the nucleolus is critical to prevent nascent DNA resection in response to replication stress., (© 2023 The Authors. Published under the terms of the CC BY NC ND 4.0 license.)
- Published
- 2023
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28. Efficacy and safety of the combination of steroid pulse therapy with methotrexate for vitiligo: A pilot retrospective case series.
- Author
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Guyon M, Merhi R, Andreu N, Boniface K, and Seneschal J
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- Humans, Methotrexate adverse effects, Retrospective Studies, Glucocorticoids, Steroids, Treatment Outcome, Vitiligo drug therapy, Hypopigmentation
- Published
- 2023
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29. The efficacy of honey or olive oil on the severity of oral mucositis and pain compared to placebo (standard care) in children with leukemia receiving intensive chemotherapy: A randomized controlled trial (RCT).
- Author
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Badr LK, El Asmar R, Hakim S, Saad R, Merhi R, Zahreddine A, and Muwakkit S
- Subjects
- Humans, Child, Olive Oil therapeutic use, Pain, Honey, Stomatitis chemically induced, Stomatitis drug therapy, Leukemia complications
- Abstract
Background: Oral mucositis (OM) is a significant complication occurring in approximately 40 to 80% of patients receiving chemotherapy regimens. Although a wide variety of agents have been tested to prevent OM or reduce its severity, none have provided conclusive evidence., Objectives: To determine the efficacy of honey or olive oil on the severity and OM pain in children with leukemia and suffering from OM compared to placebo (standard care) and, to assess which of the two interventions is more beneficial., Methods: A single blind randomized controlled study (RCT) was used to evaluate the effect of Manuka honey or olive oil, in the treatment of chemotherapy-related OM in 42 children with leukemia. The primary outcome was the severity of mucositis, using the World Health Organization (WHO) scale and the secondary outcome was the pain assessed using the Visual analogue scale (VAS)., Results: Children who received the honey had less severe OM (assessed on the (WHO) scale), p = 0.00 and less pain (assessed on the VAS scale), p = 0.00, compared to the control group. Children who received the olive oil had less pain than the control group, p = 0.00), although not lower than the honey group., Conclusion: Manuka honey or olive oil can be used as alternative therapies by nurses to children with leukemia and suffering from OM, especially in low and middle-income countries where more expensive therapies may not be available or economical., Practice Implications: Pediatric nurses may recommend Manuka honey to treat OM in children with leukemia as it is safe and inexpensive compared to other treatment modalities., Competing Interests: Conflict of interest The authors of this study certify that they have no affiliations with, or involvement in, any organization or entity with any financial interest or nonfinancial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
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30. The organizer of chromatin topology RIF1 ensures cellular resilience to DNA replication stress.
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Lebdy R, Patouillard J, Larroque M, Urbach S, Abou Merhi R, Larroque C, and Ribeyre C
- Subjects
- Aphidicolin pharmacology, DNA metabolism, DNA Replication genetics, Chromatin genetics, Telomere-Binding Proteins genetics, Telomere-Binding Proteins metabolism
- Abstract
Eukaryotic genomes are duplicated from thousands of replication origins that fire sequentially forming a defined spatiotemporal pattern of replication clusters. The temporal order of DNA replication is determined by chromatin architecture and, more specifically, by chromatin contacts that are stabilized by RIF1. Here, we show that RIF1 localizes near newly synthesized DNA. In cells exposed to the DNA replication inhibitor aphidicolin, suppression of RIF1 markedly decreased the efficacy of isolation of proteins on nascent DNA, suggesting that the isolation of proteins on nascent DNA procedure is biased by chromatin topology. RIF1 was required to limit the accumulation of DNA lesions induced by aphidicolin treatment and promoted the recruitment of cohesins in the vicinity of nascent DNA. Collectively, the data suggest that the stabilization of chromatin topology by RIF1 limits replication-associated genomic instability., (© 2023 Lebdy et al.)
- Published
- 2023
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31. Rbp95 binds to 25S rRNA helix H95 and cooperates with the Npa1 complex during early pre-60S particle maturation.
- Author
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Bhutada P, Favre S, Jaafar M, Hafner J, Liesinger L, Unterweger S, Bischof K, Darnhofer B, Siva Sankar D, Rechberger G, Abou Merhi R, Lebaron S, Birner-Gruenberger R, Kressler D, Henras AK, and Pertschy B
- Subjects
- RNA Precursors metabolism, RNA, Ribosomal chemistry, RNA-Binding Proteins genetics, RNA-Binding Proteins metabolism, Ribosomal Proteins metabolism, Saccharomyces cerevisiae genetics, Nuclear Proteins metabolism, Ribosome Subunits, Large, Eukaryotic metabolism, Saccharomyces cerevisiae Proteins metabolism
- Abstract
Eukaryotic ribosome synthesis involves more than 200 assembly factors, which promote ribosomal RNA (rRNA) processing, modification and folding, and assembly of ribosomal proteins. The formation and maturation of the earliest pre-60S particles requires structural remodeling by the Npa1 complex, but is otherwise still poorly understood. Here, we introduce Rbp95 (Ycr016w), a constituent of early pre-60S particles, as a novel ribosome assembly factor. We show that Rbp95 is both genetically and physically linked to most Npa1 complex members and to ribosomal protein Rpl3. We demonstrate that Rbp95 is an RNA-binding protein containing two independent RNA-interacting domains. In vivo, Rbp95 associates with helix H95 in the 3' region of the 25S rRNA, in close proximity to the binding sites of Npa1 and Rpl3. Additionally, Rbp95 interacts with several snoRNAs. The absence of Rbp95 results in alterations in the protein composition of early pre-60S particles. Moreover, combined mutation of Rbp95 and Npa1 complex members leads to a delay in the maturation of early pre-60S particles. We propose that Rbp95 acts together with the Npa1 complex during early pre-60S maturation, potentially by promoting pre-rRNA folding events within pre-60S particles., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2022
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32. Assessment of Vitiligo Area Scoring Index (VASI), Facial-VASI and Vitiligo Extent Score using standardized photography of patients with vitiligo.
- Author
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Merhi R, Canu D, Barnetche T, Duchez E, Gey A, Andreu N, Taieb A, Boniface K, and Seneschal J
- Subjects
- Face, Humans, Photography, Hypopigmentation, Vitiligo
- Published
- 2022
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33. Vitiligo Skin T Cells Are Prone to Produce Type 1 and Type 2 Cytokines to Induce Melanocyte Dysfunction and Epidermal Inflammatory Response Through Jak Signaling.
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Martins C, Migayron L, Drullion C, Jacquemin C, Lucchese F, Rambert J, Merhi R, Michon P, Taieb A, Rezvani HR, de Rinaldis E, Seneschal J, and Boniface K
- Subjects
- Cytokines metabolism, Epidermis metabolism, Humans, Melanocytes metabolism, T-Lymphocytes metabolism, Vitiligo pathology
- Abstract
Vitiligo is a T cell-mediated inflammatory skin disorder characterized by the loss of epidermal melanocytes. However, the contribution of melanocytes to the physiopathology of the disease in response to the T-cell microenvironment remains unclear. Here, using NanoString technology and multiplex ELISA, we show that active vitiligo perilesional skin is characterized by prominent type 1 and 2 associated immune responses. The vitiligo skin T-cell secretome downregulated melanocyte function and adhesion while increasing melanocyte mitochondrial metabolism and expression of inflammatory cytokines and chemokines by epidermal cells. The Jak1/2 inhibitor ruxolitinib strongly inhibited such effects on epidermal cells. Our data highlight that vitiligo is more complex than previously thought, with prominent combined activities of both T helper type 1- and T helper type 2-related cytokines inducing inflammatory responses of epidermal cells. Melanocytes do not appear only to be a target of T cells in vitiligo but could actively contribute to perpetuate inflammation. Jak inhibitors could prevent the impact of T cells on epidermal cells and pigmentation, highlighting their potential clinical benefit in vitiligo., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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34. Coupling Between Production of Ribosomal RNA and Maturation: Just at the Beginning.
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Azouzi C, Jaafar M, Dez C, Abou Merhi R, Lesne A, Henras AK, and Gadal O
- Abstract
Ribosomal RNA (rRNA) production represents the most active transcription in the cell. Synthesis of the large rRNA precursors (35S/47S in yeast/human) is achieved by up to hundreds of RNA polymerase I (Pol I) enzymes simultaneously transcribing a single rRNA gene. In this review, we present recent advances in understanding the coupling between rRNA production and nascent rRNA folding. Mapping of the distribution of Pol I along ribosomal DNA at nucleotide resolution, using either native elongating transcript sequencing (NET-Seq) or crosslinking and analysis of cDNAs (CRAC), revealed frequent Pol I pausing, and CRAC results revealed a direct coupling between pausing and nascent RNA folding. High density of Pol I per gene imposes topological constraints that establish a defined pattern of polymerase distribution along the gene, with a persistent spacing between transcribing enzymes. RNA folding during transcription directly acts as an anti-pausing mechanism, implying that proper folding of the nascent rRNA favors elongation in vivo . Defects in co-transcriptional folding of rRNA are likely to induce Pol I pausing. We propose that premature termination of transcription, at defined positions, can control rRNA production in vivo ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Azouzi, Jaafar, Dez, Abou Merhi, Lesne, Henras and Gadal.)
- Published
- 2021
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35. Anticancer activities of parthenolide in primary effusion lymphoma preclinical models.
- Author
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Karam L, Abou Staiteieh S, Chaaban R, Hayar B, Ismail B, Neipel F, Darwiche N, and Abou Merhi R
- Subjects
- Animals, Apoptosis drug effects, Biomarkers, Cell Cycle Checkpoints drug effects, Cell Line, Tumor, Disease Models, Animal, Disease Susceptibility, Drug Evaluation, Preclinical, Humans, Lymphoma, Primary Effusion etiology, Lymphoma, Primary Effusion metabolism, Mice, Mice, Inbred NOD, Mice, SCID, Signal Transduction drug effects, Xenograft Model Antitumor Assays, Antineoplastic Agents, Phytogenic pharmacology, Lymphoma, Primary Effusion drug therapy, Sesquiterpenes pharmacology
- Abstract
The sesquiterpene lactone parthenolide is a major component of the feverfew medicinal plant, Tanacetum parthenium. Parthenolide has been extensively studied for its anti-inflammatory and anticancer properties in several tumor models. Parthenolide's antitumor activities depend on several mechanisms but it is mainly known as an inhibitor of the nuclear factor-κB (NF-κB) pathway. This pathway is constitutively activated and induces cell survival in primary effusion lymphoma (PEL), a rare aggressive AIDS-related lymphoproliferative disorder that is commonly caused by the human herpesvirus 8 (HHV-8) infection. The aim of this study is to evaluate the targeted effect of Parthenolide both in vitro and in vivo. Herein, parthenolide significantly inhibited cell growth, induced G
0 /G1 cell cycle arrest, and induced massive apoptosis in PEL cells and ascites. In addition, parthenolide inhibited the NF-ĸB pathway suppressing IĸB phosphorylation and p65 nuclear translocation. It also reduced the expression of the DNA methylase inhibitor (DNMT1). Parthenolide induced HHV-8 lytic gene expression without inhibiting latent viral gene expression. Importantly, DMAPT, the more soluble parthenolide prodrug, promoted delay in ascites development and prolonged the survival of PEL xenograft mice. This study supports the therapeutic use of parthenolide in PEL and encourages its further clinical development., (© 2021 Wiley Periodicals LLC.)- Published
- 2021
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36. Loss of parla Function Results in Inactivity, Olfactory Impairment, and Dopamine Neuron Loss in Zebrafish.
- Author
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Merhi R, Kalyn M, Zhu-Pawlowsky A, and Ekker M
- Abstract
The presenilin-associated rhomboid-like ( PARL ) gene was found to contribute to mitochondrial morphology and function and was linked to familial Parkinson's disease (PD). The PARL gene product is a mitochondrial intramembrane cleaving protease that acts on a number of mitochondrial proteins involved in mitochondrial morphology, apoptosis, and mitophagy. To date, functional and genetic studies of PARL have been mainly performed in mammals. However, little is known about PARL function and its role in dopaminergic (DA) neuron development in vertebrates. The zebrafish genome comprises two PARL paralogs: parla and parlb . Here, we established a loss-of-function mutation in parla via CRISPR/Cas9-mediated mutagenesis. We examined DA neuron numbers in the adult brain and expression of genes associated with DA neuron function in larvae and adults. We show that loss of parla function results in loss of DA neurons, mainly in the olfactory bulb. Changes in the levels of tyrosine hydroxylase transcripts supported this neuronal loss. Expression of fis1 , a gene involved in mitochondrial fission, was increased in parla mutants. Finally, we showed that loss of parla function translates into impaired olfaction and altered locomotion parameters. These results suggest a role for parla in the development and/or maintenance of DA neuron function in zebrafish.
- Published
- 2021
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37. Lenalidomide in Combination with Arsenic Trioxide: an Effective Therapy for Primary Effusion Lymphoma.
- Author
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Moodad S, El Hajj R, Hleihel R, Hajjar L, Tawil N, Karam M, Hamie M, Abou Merhi R, El Sabban M, and El Hajj H
- Abstract
Primary effusion lymphoma (PEL) is a rare aggressive subset of non-Hodgkin B cell lymphoma. PEL is secondary to Kaposi sarcoma herpes virus (KSHV) and predominantly develops in serous cavities. Conventional chemotherapy remains the treatment of choice for PEL and yields high response rates with no significant comorbidities. Yet, chemotherapy often fails in achieving or maintaining long-term remission. Lenalidomide (Lena), an immunomodulatory drug, displayed some efficacy in the treatment of PEL. On the other hand, arsenic trioxide (ATO) in combination with other agents effectively treated a number of blood malignancies, including PEL. In this study, we present evidence that the combination of ATO/Lena significantly enhanced survival of PEL mice, decreased the volume of exacerbated ascites in the peritoneum, and reduced tumor infiltration in organs of treated animals. In ex vivo treated PEL cells, ATO/Lena decreased the proliferation and downregulated the expression of KSHV latent viral proteins. This was associated with decreased NF-κB activation, resulting in reactivation of viral replication, downregulation of interleukin-6 (IL-6) and IL-10, inhibition of vascular endothelial growth factor, and apoptosis. Our results elucidate the mechanism of action of ATO/Lena and present it as a promising targeted therapeutic modality in PEL management, which warrants further clinical investigation.
- Published
- 2020
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38. Antitumor activity of the synthetic retinoid ST1926 on primary effusion lymphoma in vitro and in vivo models.
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Karam L, Houshaymi B, Abdel-Samad R, Jaafar M, Halloum I, Pisano C, Neipel F, Darwiche N, and Abou Merhi R
- Subjects
- Adamantane administration & dosage, Adamantane pharmacology, Animals, Antineoplastic Agents pharmacology, Cell Line, Tumor, Cell Proliferation drug effects, Cell Survival drug effects, Cinnamates pharmacology, DNA Damage, Gene Expression Regulation, Neoplastic drug effects, Herpesviridae Infections genetics, Herpesvirus 8, Human drug effects, Humans, Lymphoma, Primary Effusion genetics, Lymphoma, Primary Effusion virology, Mice, Treatment Outcome, Xenograft Model Antitumor Assays, Adamantane analogs & derivatives, Antineoplastic Agents administration & dosage, Cinnamates administration & dosage, Herpesviridae Infections drug therapy, Lymphoma, Primary Effusion drug therapy
- Abstract
Primary effusion lymphoma (PEL) is a rare B-cell neoplasm, associated with Kaposi sarcoma-associated herpes virus/human herpes virus-8 (KSHV/HHV-8), arising as malignant effusions in body cavities. PEL cells do not harbor conventional genetic cancer mutations; however, their oncogenesis is mainly attributed to HHV-8 latent genes. Treatment strategies are inefficient resulting in poor prognosis of PEL patients, stressing the need for new effective therapy. ST1926 is a synthetic retinoid with favorable antitumor properties and no cross-resistance with the natural retinoid, all-trans retinoic acid. ST1926 has shown potent apoptotic activities on a variety of solid tumors and hematologic malignancies in in vitro and in vivo models. In the present study we elucidated the antitumor activities and underlying molecular mechanism of ST1926 using in vitro, ex vivo, and in vivo PEL preclinical models. ST1926, at sub‑micromolar concentrations, displayed potent antiproliferative effects on PEL cell lines and malignant ascites. Furthermore, ST1926 treatment of PEL cells and ascites resulted in their accumulation in the sub-G1 region, S phase cell cycle arrest, early DNA damage, PARP cleavage and p53 activation including the upregulation of its target genes p21 and Bax. However, ST1926 did not significantly modulate HHV-8 latent viral transcripts. Importantly, ST1926 delayed formation of ascites and enhanced survival of PEL mice. These results highlight the therapeutic potential of ST1926 in combination with drugs that target HHV-8 in PEL patients.
- Published
- 2018
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39. Extracellular vesicles released by mesenchymal-like prostate carcinoma cells modulate EMT state of recipient epithelial-like carcinoma cells through regulation of AR signaling.
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El-Sayed IY, Daher A, Destouches D, Firlej V, Kostallari E, Maillé P, Huet E, Haidar-Ahmad N, Jenster G, de la Taille A, Abou Merhi R, Terry S, and Vacherot F
- Subjects
- Androgen Antagonists pharmacology, Antineoplastic Agents, Hormonal pharmacology, Cell Line, Tumor, Cell Movement, Cell-Derived Microparticles drug effects, Cell-Derived Microparticles pathology, Dose-Response Relationship, Drug, Drug Resistance, Neoplasm, Humans, Male, Neoplasm Invasiveness, Neoplasms, Hormone-Dependent drug therapy, Neoplasms, Hormone-Dependent genetics, Neoplasms, Hormone-Dependent pathology, Phenotype, Prostatic Neoplasms drug therapy, Prostatic Neoplasms genetics, Prostatic Neoplasms pathology, Receptors, Androgen drug effects, Receptors, Androgen genetics, Time Factors, Transforming Growth Factor beta1 genetics, Transforming Growth Factor beta1 metabolism, Tumor Microenvironment, Cell-Derived Microparticles metabolism, Epithelial-Mesenchymal Transition drug effects, Neoplasms, Hormone-Dependent metabolism, Prostatic Neoplasms metabolism, Receptors, Androgen metabolism, Signal Transduction drug effects
- Abstract
Extracellular vesicles released from cancer cells may play an important role in cancer progression by shuttling oncogenic information into recipient cells. However, our knowledge is still fragmentary and there remain numerous questions regarding the mechanisms at play and the functional consequences of these interactions. We have recently established a mesenchymal-like prostate cancer cell line (22Rv1/CR-1; Mes-PCa). In this study, we assessed the effects of the extracellular vesicles released by these cells on recipient androgen-dependent epithelial VCaP prostate cancer cells. Mes-PCa derived vesicles were found to promote mesenchymal features in the recipient epithelial-like prostate cancer cells. This transformation was accompanied by a modulation of androgen receptor signaling and activation of TGFβ signaling pathway. Moreover, recipient cells acquiring mesenchymal traits displayed enhanced migratory and invasive features as well as increased resistance to the androgen receptor antagonist, enzalutamide. Our results suggest a previously unappreciated role for Mes-PCa secreted vesicles in cancer promotion by transferring cell-mediated signals and promoting phenotypic changes in recipient prostate cancer cells., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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40. Carvedilol for the treatment of red scrotum syndrome.
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Merhi R, Ayoub N, and Mrad M
- Published
- 2017
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41. Brucellosis: A lymphoma-like presentation.
- Author
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Massoud M, Kerbage F, Antoun L, Merhi R, Hallit S, and Hallit R
- Abstract
Brucellosis is one of the most common zoonotic infections worldwide caused by gram negative bacilli of the genus Brucella. It is transmitted to humans by contact with infected animals or derived food products such as unpasteurized milk. Brucellosis' clinical presentation varies widely from multi-systemic involvement to asymptomatic infection. We present the case of a 52-year-old Lebanese male who was admitted to our hospital with a 3-week history of fever (up to 40 °C), chills, night sweats and abdominal pain. Abdominal CT scan revealed the presence of several mesenteric lymphadenopathies and some retroperitoneal lymphadenopathies. Blood cultures came back positive for Brucella melitensis, and a follow-up CT of the abdomen done after treatment revealed complete resolution of the lymphadenopathies. To our knowledge, this is the first case in the literature of brucellosis presenting as retroperitoneal and mesenteric lymphadenopathies. In endemic areas, the diagnosis of brucellosis should always be raised in front of any long duration fever even in the absence of a typical clinical presentation., (Copyright © 2017 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.)
- Published
- 2017
- Full Text
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42. An ATR-dependent function for the Ddx19 RNA helicase in nuclear R-loop metabolism.
- Author
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Hodroj D, Recolin B, Serhal K, Martinez S, Tsanov N, Abou Merhi R, and Maiorano D
- Subjects
- Animals, Ataxia Telangiectasia Mutated Proteins metabolism, Checkpoint Kinase 1 metabolism, Xenopus Proteins metabolism, DEAD-box RNA Helicases metabolism, DNA Damage, DNA Repair, RNA metabolism, Xenopus metabolism
- Abstract
Coordination between transcription and replication is crucial in the maintenance of genome integrity. Disturbance of these processes leads to accumulation of aberrant DNA:RNA hybrids (R-loops) that, if unresolved, generate DNA damage and genomic instability. Here we report a novel, unexpected role for the nucleopore-associated mRNA export factor Ddx19 in removing nuclear R-loops formed upon replication stress or DNA damage. We show, in live cells, that Ddx19 transiently relocalizes from the nucleopore to the nucleus upon DNA damage, in an ATR/Chk1-dependent manner, and that Ddx19 nuclear relocalization is required to clear R-loops. Ddx19 depletion induces R-loop accumulation, proliferation-dependent DNA damage and defects in replication fork progression. Further, we show that Ddx19 resolves R-loops in vitro via its helicase activity. Furthermore, mutation of a residue phosphorylated by Chk1 in Ddx19 disrupts its interaction with Nup214 and allows its nuclear relocalization. Finally, we show that Ddx19 operates in resolving R-loops independently of the RNA helicase senataxin. Altogether these observations put forward a novel, ATR-dependent function for Ddx19 in R-loop metabolism to preserve genome integrity in mammalian cells., (© 2017 The Authors.)
- Published
- 2017
- Full Text
- View/download PDF
43. Endothelial Microparticles From Acute Coronary Syndrome Patients Induce Premature Coronary Artery Endothelial Cell Aging and Thrombogenicity: Role of the Ang II/AT1 Receptor/NADPH Oxidase-Mediated Activation of MAPKs and PI3-Kinase Pathways.
- Author
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Abbas M, Jesel L, Auger C, Amoura L, Messas N, Manin G, Rumig C, León-González AJ, Ribeiro TP, Silva GC, Abou-Merhi R, Hamade E, Hecker M, Georg Y, Chakfe N, Ohlmann P, Schini-Kerth VB, Toti F, and Morel O
- Subjects
- Humans, Risk Factors, Acute Coronary Syndrome metabolism, Angiotensin II pharmacology, Cellular Senescence drug effects, MAP Kinase Kinase 1 metabolism, NADPH Oxidases metabolism, Phosphatidylinositol 3-Kinases metabolism
- Abstract
Background: Microparticles (MPs) have emerged as a surrogate marker of endothelial dysfunction and cardiovascular risk. This study examined the potential of MPs from senescent endothelial cells (ECs) or from patients with acute coronary syndrome (ACS) to promote premature EC aging and thrombogenicity., Methods: Primary porcine coronary ECs were isolated from the left circumflex coronary artery. MPs were prepared from ECs and venous blood from patients with ACS (n=30) and from healthy volunteers (n=4) by sequential centrifugation. The level of endothelial senescence was assessed as senescence-associated β-galactosidase activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, tissue factor activity using an enzymatic Tenase assay, the level of target protein expression by Western blot analysis, platelet aggregation using an aggregometer, and shear stress using a cone-and-plate viscometer., Results: Senescence, as assessed by senescence-associated β-galactosidase activity, was induced by the passaging of porcine coronary artery ECs from passage P1 to P4, and was associated with a progressive shedding of procoagulant MPs. Exposure of P1 ECs to MPs shed from senescent P3 cells or circulating MPs from ACS patients induced increased senescence-associated β-galactosidase activity, oxidative stress, early phosphorylation of mitogen-activated protein kinases and Akt, and upregulation of p53, p21, and p16. Ex vivo, the prosenescent effect of circulating MPs from ACS patients was evidenced only under conditions of low shear stress. Depletion of endothelial-derived MPs from ACS patients reduced the induction of senescence. Prosenescent MPs promoted EC thrombogenicity through tissue factor upregulation, shedding of procoagulant MPs, endothelial nitric oxide synthase downregulation, and reduced nitric oxide-mediated inhibition of platelet aggregation. These MPs exhibited angiotensin-converting enzyme activity and upregulated AT1 receptors and angiotensin-converting enzyme in P1 ECs. Losartan, an AT1 receptor antagonist, and inhibitors of either mitogen-activated protein kinases or phosphoinositide 3-kinase prevented the MP-induced endothelial senescence., Conclusions: These findings indicate that endothelial-derived MPs from ACS patients induce premature endothelial senescence under atheroprone low shear stress and thrombogenicity through angiotensin II-induced redox-sensitive activation of mitogen-activated protein kinases and phosphoinositide 3-kinase/Akt. They further suggest that targeting endothelial-derived MP shedding and their bioactivity may be a promising therapeutic strategy to limit the development of an endothelial dysfunction post-ACS., (© 2016 American Heart Association, Inc.)
- Published
- 2017
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44. Hsp90 inhibition by AUY922 as an effective treatment strategy against myxoid liposarcoma.
- Author
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Steinmann S, Gali-Muhtasib H, Huebner K, Al-Halabi R, Abou Merhi R, Aman P, Agaimy A, Haller F, and Schneider-Stock R
- Subjects
- Animals, Apoptosis drug effects, Cell Proliferation drug effects, Cell Survival drug effects, Dose-Response Relationship, Drug, G2 Phase Cell Cycle Checkpoints drug effects, HCT116 Cells, HSP90 Heat-Shock Proteins metabolism, Humans, Liposarcoma, Myxoid genetics, Liposarcoma, Myxoid metabolism, Liposarcoma, Myxoid pathology, MAP Kinase Signaling System drug effects, Mice, Inbred NOD, Mice, SCID, Molecular Targeted Therapy, Phosphatidylinositol 3-Kinase metabolism, Proto-Oncogene Proteins c-akt metabolism, Time Factors, Xenograft Model Antitumor Assays, Antineoplastic Agents pharmacology, HSP90 Heat-Shock Proteins antagonists & inhibitors, Isoxazoles pharmacology, Liposarcoma, Myxoid drug therapy, Resorcinols pharmacology
- Abstract
Liposarcoma is one of the most common soft tissue sarcomas in adults. Recognized histological subtypes include well differentiated/dedifferentiated liposarcoma (WD/DDLS), myxoid liposarcoma (MLS) and pleomorphic liposarcoma. Currently, there are no proper subtype-specific treatments due to the genetic, histological and clinical heterogeneity of the liposarcoma subentities. In the past decade, the rising understanding of the various genetic and molecular aberrations in liposarcoma led to the development of novel alternative therapeutic strategies. One such therapy is the inhibition of the heat shock protein 90 (Hsp90) which is overexpressed in liposarcomas. In this study, we dissect the functional role of a novel potent Hsp90 inhibitor NVP-AUY922 (AUY922) in different cell lines of myxoid (MLS402, MLS1765) and undifferentiated (SW872) liposarcomas. We show that compared with 17-AAG treatment, lower concentrations of AUY922 achieve markedly cytotoxic effects on tumor cell viability. Combination treatment of AUY922 (20 nM) with Doxorubicin (300 nM) yielded a further reduction in cell viability in comparison to Doxorubicin alone. In vivo, we document an inhibition of tumor growth after AUY922 treatment. Further analyses revealed that Hsp90-inhibition induces apoptotic cell death and cell cycle arrest. In addition, we report striking perturbations of subtype-specific pattern in Raf/MEK/ERK and PI3K signaling after AUY922 application. In conclusion, our results provide evidence that Hsp90-inhibition by AUY922 may be a promising alternative therapeutic strategy for myxoid liposarcoma patients., (Copyright © 2015. Published by Elsevier Ireland Ltd.)
- Published
- 2015
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45. Gallotannin is a DNA damaging compound that induces senescence independently of p53 and p21 in human colon cancer cells.
- Author
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Al-Halabi R, Abou Merhi R, Chakilam S, El-Baba C, Hamade E, Di Fazio P, Ocker M, Schneider-Stock R, and Gali-Muhtasib H
- Subjects
- Antioxidants metabolism, Catalase metabolism, Cell Cycle Checkpoints drug effects, Cell Line, Tumor, Colonic Neoplasms metabolism, Dithiothreitol metabolism, HCT116 Cells, Humans, Reactive Oxygen Species metabolism, S Phase drug effects, Superoxide Dismutase metabolism, Cellular Senescence drug effects, Colonic Neoplasms drug therapy, Cyclin-Dependent Kinase Inhibitor p21 metabolism, DNA Damage drug effects, Hydrolyzable Tannins pharmacology, Tumor Suppressor Protein p53 metabolism
- Abstract
The plant secondary metabolite gallotannin (GT) is the simplest hydrolyzable tannin shown to have anti-carcinogenic properties in several cell lines and to inhibit tumor development in different animal models. Here, we determined if GT induces senescence and DNA damage and investigated the involvement of p53 and p21 in this response. Using HCT116 human colon cancer cells wildtype for p53(+/+) /p21(+/+) and null for p53(+/+) /p21(-/-) or p53(-/-) /p21(+/+) , we found that GT induces senescence independently of p21 and p53. GT was found to increase the production of reactive oxygen species (ROS) by altering the redox balance in the cell, mainly by reducing the levels of glutathione and superoxide dismutase (SOD). Using the key antioxidants N-acetyl cysteine, dithiothreitol, SOD, and catalase, we showed that ROS were partially involved in the senescence response. Furthermore, GT-induced cell cycle arrest in S-phase in all HCT116 cell lines. At later time points, we noticed that p53 and p21 null cells escaped complete arrest and re-entered cell cycle provoking higher rates of multinucleation. The senescence induction by GT was irreversible and was accompanied by significant DNA damage as evidenced by p-H2AX staining. Our findings indicate that GT is an interesting anti colon cancer agent which warrants further study., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2015
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46. Functional and splicing defect analysis of 23 ACVRL1 mutations in a cohort of patients affected by Hereditary Hemorrhagic Telangiectasia.
- Author
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Alaa El Din F, Patri S, Thoreau V, Rodriguez-Ballesteros M, Hamade E, Bailly S, Gilbert-Dussardier B, Abou Merhi R, and Kitzis A
- Subjects
- Base Sequence, Blotting, Western, Cohort Studies, Growth Differentiation Factor 2 pharmacology, HeLa Cells, Humans, Molecular Sequence Data, Protein Transport drug effects, Subcellular Fractions metabolism, Activin Receptors, Type II genetics, Mutation genetics, RNA Splicing genetics, Telangiectasia, Hereditary Hemorrhagic genetics
- Abstract
Hereditary Hemorrhagic Telangiectasia syndrome (HHT) or Rendu-Osler-Weber (ROW) syndrome is an autosomal dominant vascular disorder. Two most common forms of HHT, HHT1 and HHT2, have been linked to mutations in the endoglin (ENG) and activin receptor-like kinase 1 (ACVRL1or ALK1) genes respectively. This work was designed to examine the pathogenicity of 23 nucleotide variations in ACVRL1 gene detected in more than 400 patients. Among them, 14 missense mutations and one intronic variant were novels, and 8 missense mutations were previously identified with questionable implication in HHT2. The functionality of missense mutations was analyzed in response to BMP9 (specific ligand of ALK1), the maturation of the protein products and their localization were analyzed by western blot and fluorescence microscopy. The splicing impairment of the intronic and of two missense mutations was examined by minigene assay. Functional analysis showed that 18 out of 22 missense mutations were defective. Splicing analysis revealed that one missense mutation (c.733A>G, p.Ile245Val) affects the splicing of the harboring exon 6. Similarly, the intronic mutation outside the consensus splicing sites (c.1048+5G>A in intron 7) was seen pathogenic by splicing study. Both mutations induce a frame shift creating a premature stop codon likely resulting in mRNA degradation by NMD surveillance mechanism. Our results confirm the haploinsufficiency model proposed for HHT2. The affected allele of ACVRL1 induces mRNA degradation or the synthesis of a protein lacking the receptor activity. Furthermore, our data demonstrate that functional and splicing analyses together, represent two robust diagnostic tools to be used by geneticists confronted with novel or conflicted ACVRL1 mutations.
- Published
- 2015
- Full Text
- View/download PDF
47. Proliferation and differentiation of human adipose-derived mesenchymal stem cells (ASCs) into osteoblastic lineage are passage dependent.
- Author
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Di Battista JA, Shebaby W, Kizilay O, Hamade E, Abou Merhi R, Mebarek S, Abdallah D, Badran B, Saad F, K Abdalla E, and Faour WH
- Subjects
- Adult, Aged, Cell Differentiation, Cell Proliferation, Cells, Cultured, Humans, Middle Aged, Osteogenesis, Adipose Tissue cytology, Mesenchymal Stem Cells cytology, Osteoblasts cytology
- Abstract
Objective: The effect of in vitro expansion of human adipose-derived stem cells (ASCs) on stem cell properties is controversial. We examined serial subcultivation with expansion on the ability of ASCs to grow and differentiate into osteoblastic lineages., Design: Flow cytometric analysis, growth kinetics, cell population doubling time, light microscopy and confocal analysis, and osteogenesis induction were performed to assess growth and osteogenic potential of subcultivated ASCs at passages 2 (P2), P4 and P6., Results: Flow cytometric analysis revealed that ASCs at P2 express classical mesenchymal stem cell markers including CD44, CD73, and CD105, but not CD14, CD19, CD34, CD45, or HLA-DR. Calcium deposition and alkaline phosphatase activity were the highest at P2 but completely abrogated at P4. Increased passage number impaired cell growth; P2 cultures exhibited exponential growth, while cells at P4 and P6 showed near linear growth with cell population doubling times increased from 3.2 at P2 to 4.8 d at P6. Morphologically, cells in various subcultivation stages showed flattened shape at low density but spindle-like structures at confluency as judged by phalloidin staining., Conclusions: Osteogenic potential of ASCs is impaired by successive passaging and may not serve as a useful clinical source of osteogenic ASCs past P2.
- Published
- 2014
- Full Text
- View/download PDF
48. Combination of arsenic and interferon-α inhibits expression of KSHV latent transcripts and synergistically improves survival of mice with primary effusion lymphomas.
- Author
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El Hajj H, Ali J, Ghantous A, Hodroj D, Daher A, Zibara K, Journo C, Otrock Z, Zaatari G, Mahieux R, El Sabban M, Bazarbachi A, and Abou Merhi R
- Subjects
- Animals, Apoptosis drug effects, Cell Line, Tumor, Drug Synergism, Herpesvirus 8, Human genetics, Herpesvirus 8, Human pathogenicity, Humans, Lymphoma, Primary Effusion pathology, Lymphoma, Primary Effusion virology, Mice, Transcription, Genetic drug effects, Arsenic administration & dosage, Herpesvirus 8, Human drug effects, Interferon-alpha administration & dosage, Lymphoma, Primary Effusion drug therapy
- Abstract
Background: Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphomas (PEL). PEL cell lines infected with KSHV, but negative for Epstein-Barr virus have a tumorigenic potential in non-obese diabetic/severe combined immunodeficient mice and result in efficient engraftment and formation of malignant ascites with notable abdominal distension, consistent with the clinical manifestations of PEL in humans., Methodology/principal Findings: Using this preclinical mouse model, we demonstrate that the combination of arsenic trioxide and interferon-alpha (IFN) inhibits proliferation, induces apoptosis and downregulates the latent viral transcripts LANA-1, v-FLIP and v-Cyc in PEL cells derived from malignant ascites. Furthermore, this combination decreases the peritoneal volume and synergistically increases survival of PEL mice., Conclusion/significance: These results provide a promising rationale for the therapeutic use of arsenic/IFN in PEL patients.
- Published
- 2013
- Full Text
- View/download PDF
49. Gallotannin inhibits NFĸB signaling and growth of human colon cancer xenografts.
- Author
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Al-Halabi R, Bou Chedid M, Abou Merhi R, El-Hajj H, Zahr H, Schneider-Stock R, Bazarbachi A, and Gali-Muhtasib H
- Subjects
- Animals, Antineoplastic Agents, Phytogenic administration & dosage, Cell Cycle drug effects, Cell Line, Tumor, Colonic Neoplasms metabolism, Colonic Neoplasms pathology, Cytokines metabolism, Female, G1 Phase drug effects, Humans, Hydrolyzable Tannins administration & dosage, I-kappa B Kinase drug effects, I-kappa B Kinase metabolism, Inflammation Mediators metabolism, Injections, Intraperitoneal, Interleukin-1alpha genetics, Interleukin-6 genetics, Mice, Mice, Inbred NOD, Microvessels drug effects, Microvessels metabolism, NF-kappa B antagonists & inhibitors, NF-kappa B metabolism, Platelet Endothelial Cell Adhesion Molecule-1 drug effects, Platelet Endothelial Cell Adhesion Molecule-1 metabolism, RNA, Messenger, Signal Transduction drug effects, Tumor Necrosis Factor-alpha drug effects, Tumor Necrosis Factor-alpha genetics, Xenograft Model Antitumor Assays, Antineoplastic Agents, Phytogenic pharmacology, Colonic Neoplasms drug therapy, Hydrolyzable Tannins pharmacology, NF-kappa B p50 Subunit antagonists & inhibitors, NF-kappa B p50 Subunit metabolism
- Abstract
Gallotannin (GT), the polyphenolic hydrolyzable tannin, exhibits anti-inflammatory and anticancer activities through mechanisms that are not fully understood. Several effects modulated by GT have been shown to be linked to interference with inflammatory mediators. Considering the central role of nuclear factor kappa B (NF-ĸB) in inflammation and cancer, we investigated the effect of GT on NF-ĸB signaling in HT-29 and HCT-116 human colon cancer cells. DNA binding assays revealed significant suppression of tumor necrosis factor (TNF-α)-induced NFĸB activation which correlated with the inhibition of IĸBα phosphorylation and degradation. Sequentially, p65 nuclear translocation and DNA binding were inhibited. GT also down-regulated the expression of NFĸB-regulated inflammatory cytokines (IL-8, TNF-α, IL-1α) and caused cell cycle arrest and accumulation of cells in pre-G 1 phase. In vivo, GT (25 mg/kg body weight) injected intraperitoneally (i.p.) prior to or after tumor inoculation significantly decreased the volume of human colon cancer xenografts in NOD/SCID mice. GT-treated xenografts showed significantly lower microvessel density (CD31) as well as lower mRNA expression levels of IL-6, TNF-α and IL-1α and of the proliferation (Ki-67) and angiogenesis (VEGFA) proteins, which may explain GTs in vivo anti-tumorigenic effects. Overall, our results indicate that the anti-inflammatory and antitumor activities of GT may be mediated in part through the suppression of NF-ĸB activation.
- Published
- 2011
- Full Text
- View/download PDF
50. Significance of CEA and VEGF as Diagnostic Markers of Colorectal Cancer in Lebanese Patients.
- Author
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Dbouk HA, Tawil A, Nasr F, Kandakarjian L, and Abou-Merhi R
- Abstract
Carcinoembryonic antigen and vascular endothelial growth factors are among the most important prognostic markers of colorectal cancer. Testing for these markers independently has been of limited value in screening for this tumor. The aim of this study is to determine the importance of simultaneous blood CEA and VEGF level determinations in diagnosis of colorectal cancer. Thirty-six patients diagnosed with colorectal cancer along with eight healthy controls were tested by ELISA for CEA and VEGF levels in serum and plasma, respectively. The positive predictive value of these markers was 95.4% for CEA and 89.5% for VEGF, and for combined CEA and VEGF was also high at 88%. Combined CEA and VEGF blood level assay constitutes a useful panel in detecting patients with colorectal cancer. Positive results allow selection of a subgroup of patients with a high tumor risk; therefore, such tests comprise valuable tumor diagnostic tests to add to current detection methods.
- Published
- 2007
- Full Text
- View/download PDF
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