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Elmaleh Y, Yavchitz A, Léguillier T, Squara PA, Palpacuer C, Grégoire C. Feasibility of Prone Positioning for Brain-injured Patients with Severe Acute Respiratory Distress Syndrome: A Systematic Review and Pilot Study (ProBrain). Anesthesiology 2024; 140:495-512. [PMID: 38088786 DOI: 10.1097/aln.0000000000004875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
BACKGROUND Prone position is a key component to treat hypoxemia in patients with severe acute respiratory distress syndrome. However, most studies evaluating it exclude patients with brain injuries without any medical evidence. METHODS This study includes a systematic review to determine whether brain-injured patients were excluded in studies evaluating prone position on acute respiratory distress syndrome; a prospective study including consecutive brain-injured patients needing prone position. The primary endpoint was the evaluation of cerebral blood flow using transcranial Doppler after prone positioning. Secondary outcomes were intracranial pressure, cerebral perfusion pressure, and tissue oxygen pressure. RESULTS From 8,183 citations retrieved, 120 studies were included in the systematic review. Among them, 90 studies excluded brain-injured patients (75%) without any justification, 16 included brain-injured patients (4 randomized, 7 nonrandomized studies, 5 retrospective), and 14 did not retrieve brain-injured data. Eleven patients were included in the authors' pilot study. No reduction of cerebral blood flow surrogates was observed during prone positioning, with diastolic speed values (mean ± SD) ranging from 37.7 ± 16.2 cm/s to 45.2 ± 19.3 cm/s for the right side (P = 0.897) and 39.6 ± 18.2 cm/s to 46.5 ± 21.3 cm/s for the left side (P = 0.569), and pulsatility index ranging from 1.14 ± 0.31 to 1.0 ± 0.32 for the right side (P = 0.145) and 1.14 ± 0.31 to 1.02 ± 0.2 for the left side (P = 0.564) before and during prone position. CONCLUSIONS Brain-injured patients are largely excluded from studies evaluating prone position in acute respiratory distress syndrome. However, cerebral blood flow seems not to be altered considering increasing of mean arterial pressure during the session. Systematic exclusion of brain-injured patients appears to be unfounded, and prone position, while at risk in brain-injured patients, should be evaluated on these patients to review recommendations, considering close monitoring of neurologic and hemodynamic parameters. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Yoann Elmaleh
- Intensive Care Unit, Rothschild Foundation Hospital, Paris, France; Quincy Anesthesiology, Private Hospital Claude Galien, Boussy Saint Antoine, France
| | - Amélie Yavchitz
- Clinical Research Department, Rothschild Foundation Hospital, Paris, France
| | - Teddy Léguillier
- Clinical Research Department, Rothschild Foundation Hospital, Paris, France
| | | | - Clément Palpacuer
- Clinical Research Department, Rothschild Foundation Hospital, Paris, France
| | - Charles Grégoire
- Intensive Care Unit, Rothschild Foundation Hospital, Paris, France
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Rangon CM, Barruet R, Mazouni A, Le Cossec C, Thevenin S, Guillaume J, Léguillier T, Huysman F, Luis D. PO041 / #457 AURICULAR NEUROMODULATION FOR AFFORDABLE MASS VAGUS NERVE STIMULATION DURING THE COVID-19 PANDEMIC. Neuromodulation 2022. [PMCID: PMC9530306 DOI: 10.1016/j.neurom.2022.08.215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Claire Marie Rangon
- Hôpital Fondation ophtalmologique A. de Rothschild, Neurosurgery, Paris, France
| | - Regine Barruet
- Centre Hospitalier Simone Veil, Infectious Disease, Beauvais, France
| | | | - Chloé Le Cossec
- Hôpital Fondation A. De Rothschild, Clinical Research Department, Paris, France
| | - Sophie Thevenin
- Hôpital Fondation A. De Rothschild, Clinical Research Department, Paris, France
| | - Jessica Guillaume
- Hôpital Fondation A. De Rothschild, Clinical Research Department, Paris, France
| | - Teddy Léguillier
- Hôpital Fondation A. De Rothschild, Clinical Research Department, Paris, France
| | - Fabienne Huysman
- Centre Hospitalier Simone Veil, Clinical Research Department, Beauvais, France
| | - David Luis
- Centre Hospitalier Simone Veil, Clinical Research Department, Beauvais, France
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Rangon CM, Barruet R, Mazouni A, Le Cossec C, Thevenin S, Guillaume J, Léguillier T, Huysman F, Luis D. Auricular Neuromodulation for Mass Vagus Nerve Stimulation: Insights From SOS COVID-19 a Multicentric, Randomized, Controlled, Double-Blind French Pilot Study. Front Physiol 2021; 12:704599. [PMID: 34408665 PMCID: PMC8365750 DOI: 10.3389/fphys.2021.704599] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022] Open
Abstract
Importance: An exacerbated inflammatory response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is believed to be one of the major causes of the morbidity and mortality of the coronavirus disease 2019 (COVID-19). Neuromodulation therapy, based on vagus nerve stimulation, was recently hypothesized to control both the SARS-CoV-2 replication and the ensuing inflammation likely through the inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and could improve the clinical outcomes as an adjunct treatment. We proposed to test it by the stimulation of the auricular branch of the vagus nerve, i.e., auricular neuromodulation (AN), a non-invasive procedure through the insertion of semipermanent needles on the ears. Objective: The aim of this study was to assess the effect of AN on the clinical outcomes in patients affected by COVID-19. Design, Setting, and Participants: A multicenter, randomized, placebo-controlled, double-blind clinical trial included 31 patients with respiratory failure due to COVID-19 requiring hospitalization. Within 72 h after admission, patients received either AN (n = 14) or sham neuromodulation (SN, n = 15) in addition to the conventional treatments. Main Outcome and Measures: The primary endpoint of the study was the rate of a clinical benefit conferred by AN at Day 14 (D14) as assessed by a 7-point Clinical Progression Scale. The secondary endpoint of the study was the impact of AN on the rate of transfer to the intensive care unit (ICU) and on the survival rate at D14. Results: The AN procedure was well-tolerated without any reported side effects but with no significant improvement for the measures of both primary (p > 0.3) and secondary (p > 0.05) endpoints at the interim analysis. None of the AN-treated patients died but one in the SN group did (81 years). Two AN-treated patients (73 and 79 years, respectively) and one SN-treated patient (59 years) were transferred to ICU. Remarkably, AN-treated patients were older with more representation by males than in the SN arm (i.e., the median age of 75 vs. 65 years, 79% male vs. 47%). Conclusion: The AN procedure, which was used within 72 h after the admission of patients with COVID-19, was safe and could be successfully implemented during the first two waves of COVID-19 in France. Nevertheless, AN did not significantly improve the outcome of the patients in our small preliminary study. It is pertinent to explore further to validate AN as the non-invasive mass vagal stimulation solution for the forthcoming pandemics. Clinical Trial Registration: [https://clinicaltrials.gov/], identifier [NCT04341415].
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Affiliation(s)
- Claire-Marie Rangon
- Pain and Neuromodulation Unit, Neurosurgery Department, Hôpital Fondation Adolphe de Rothschild, Paris, France
| | - Régine Barruet
- Infectious Diseases Department, Centre Hospitalier Simone Veil, Beauvais, France
| | | | - Chloé Le Cossec
- Clinical Research Department, Hôpital Fondation Adolphe de Rothschild, Paris, France
| | - Sophie Thevenin
- Clinical Research Department, Hôpital Fondation Adolphe de Rothschild, Paris, France
| | - Jessica Guillaume
- Clinical Research Department, Hôpital Fondation Adolphe de Rothschild, Paris, France
| | - Teddy Léguillier
- Clinical Research Department, Hôpital Fondation Adolphe de Rothschild, Paris, France
| | - Fabienne Huysman
- Clinical Research Department, Centre Hospitalier Simone Veil, Beauvais, France
| | - David Luis
- Clinical Research Department, Centre Hospitalier Simone Veil, Beauvais, France.,Intensive Care Unit, Centre Hospitalier Simone Veil, Beauvais, France
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Jouffroy R, Gilbert B, Tourtier JP, Bloch-Laine E, Ecollan P, Bounes V, Boularan J, Léguillier T, Gueye-Ngalgou P, Vivien B. Impact of Prehospital Antibiotic Therapy on Septic Shock Mortality. PREHOSP EMERG CARE 2021; 25:317-324. [PMID: 32352890 DOI: 10.1080/10903127.2020.1763532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 04/28/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Septic shock (SS) is associated with high morbidity and mortality rate. Early antibiotic therapy administration in septic patients was shown to reduce mortality but its impact on mortality in a prehospital setting is still under debate. To clarify this point, we performed a retrospective analysis on patients with septic shock who received antibiotics in a prehospital setting. Methods: From April 15th, 2017 to March 1st, 2020, patients with septic shock requiring Mobile Intensive Care Unit (MICU) intervention were retrospectively analyzed to assess the impact of prehospital antibiotic therapy administration on a 30-day mortality. Results: Three-hundred-eight patients with septic shock requiring MICU intervention in the prehospital setting were analyzed. The mean age of the study population was 70 ± 15 years. Presumed origin of SS was mainly pulmonary (44%), digestive (21%) or urinary (19%) infection. Overall 30-day mortality was 29%. Ninety-eight (32%) patients received antibiotic therapy. Using Cox regression analysis, we showed that prehospital antibiotic therapy significantly reduces 30-day mortality for patients with septic shock (hazard ratio = 0.56, 95%CI [0.35-0.89], p = 0.016). Conclusion: In this retrospective study, prehospital antibiotic therapy reduces 30-day mortality of septic shock patients cared for by MICU. Further studies will be needed to confirm the beneficial effect of prehospital antibiotic therapy in association or not with prehospital hemodynamic optimization to improve the survival of septic shock patients.
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Léguillier T, Favier R, Harroche A, Lasne D, Bachelot-Loza C, Borgel D, Boussaroque A, Pascreau T, Lallemant-Dudek P, Gkalea V, Haguet MC, Cormier-Daire V, Beaudeux JL, Monnot S, Lapillonne H, Baujat G, Forin V, Nivet-Antoine V. Assessing bleeding risk in 18 children with Osteogenesis imperfecta. Br J Haematol 2021; 192:785-788. [PMID: 33475155 DOI: 10.1111/bjh.17303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Teddy Léguillier
- Department of Clinical Biochemistry, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1140, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - Rémi Favier
- Department of Haematology, Reference Centre for Platelet Disorders, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Annie Harroche
- Department of Haematology, Haemophilia Care Centre, Necker Enfants Malades Hospital, APHP, Paris, France
| | - Dominique Lasne
- Department of Haematology, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1176, Paris-Sud University, Paris-Saclay University, le Kremlin-Bicêtre, France
| | | | - Delphine Borgel
- Department of Haematology, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1176, Paris-Sud University, Paris-Saclay University, le Kremlin-Bicêtre, France
| | - Agathe Boussaroque
- Department of Clinical Biochemistry, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1140, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - Tiffany Pascreau
- Department of Haematology, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1176, Paris-Sud University, Paris-Saclay University, le Kremlin-Bicêtre, France
| | - Pauline Lallemant-Dudek
- Department of Paediatric Physical Therapy and Rehabilitation, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Vasiliki Gkalea
- Department of Haematology, Reference Centre for Platelet Disorders, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Marie-Clotilde Haguet
- Department of Clinical Biochemistry, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Valérie Cormier-Daire
- Department of Medical Genetics, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Jean-Louis Beaudeux
- Department of Clinical Biochemistry, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1139, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - Sophie Monnot
- Department of Medical Genetics, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Hélène Lapillonne
- Department of Haematology, Reference Centre for Platelet Disorders, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Geneviève Baujat
- Department of Medical Genetics, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Véronique Forin
- Department of Paediatric Physical Therapy and Rehabilitation, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Valérie Nivet-Antoine
- Department of Clinical Biochemistry, Necker Enfants Malades Hospital, AP-HP, Paris, France.,INSERM UMR_S1140, Faculty of Pharmacy, Paris Descartes University, Paris, France
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Léguillier T, Jouffroy R, Boisson M, Boussaroque A, Chenevier-Gobeaux C, Chaabouni T, Vivien B, Nivet-Antoine V, Beaudeux JL. Lactate POCT in mobile intensive care units for septic patients? A comparison of capillary blood method versus venous blood and plasma-based reference methods. Clin Biochem 2018. [DOI: 10.1016/j.clinbiochem.2018.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Léguillier T, Lecsö-Bornet M, Lémus C, Rousseau-Ralliard D, Lebouvier N, Hnawia E, Nour M, Aalbersberg W, Ghazi K, Raharivelomanana P, Rat P. The Wound Healing and Antibacterial Activity of Five Ethnomedical Calophyllum inophyllum Oils: An Alternative Therapeutic Strategy to Treat Infected Wounds. PLoS One 2015; 10:e0138602. [PMID: 26406588 PMCID: PMC4583440 DOI: 10.1371/journal.pone.0138602] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 09/01/2015] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Calophyllum inophyllum L. (Calophyllaceae) is an evergreen tree ethno-medically used along the seashores and islands of the Indian and Pacific Oceans, especially in Polynesia. Oil extracted from the seeds is traditionally used topically to treat a wide range of skin injuries from burn, scar and infected wounds to skin diseases such as dermatosis, urticaria and eczema. However, very few scientific studies reported and quantified the therapeutic properties of Calophyllum inophyllum oil (CIO). In this work, five CIO from Indonesia (CIO1), Tahiti (CIO2, 3), Fiji islands (CIO4) and New Caledonia (CIO5) were studied and their cytotoxic, wound healing, and antibacterial properties were presented in order to provide a scientific support to their traditional use and verify their safety. METHODS The safety of the five CIO was ascertained using the Alamar blue assay on human keratinocyte cells. CIO wound healing properties were determined using the scratch test assay on human keratinocyte cells. CIO-stimulated antibacterial innate immune response was evaluated using ELISA by measuring β defensin-2 release in human derivative macrophage cells. CIO antibacterial activity was tested using oilogramme against twenty aerobic Gram- bacteria species, twenty aerobic Gram+ bacteria species, including a multi-drug resistant Staphylococcus aureus strain and two anaerobic Gram+ bacteria species e.g. Propionibacterium acnes and Propionibacterium granulosum. To detect polarity profile of the components responsible of the antibacterial activity, we performed bioautography against a Staphylococcus aureus strain. RESULTS Based on Alamar Blue assay, we showed that CIO can be safely used on keratinocyte cells between 2.7% and 11.2% depending on CIO origin. Concerning the healing activity, all the CIO tested accelerated in vitro wound closure, the healing factor being 1.3 to 2.1 higher compared to control when keratinocytes were incubated after scratch with CIO at 0.1%. Furthermore, our results showed that CIO exhibit two distinct antibacterial effects: one against Gram+ bacteria by direct inhibition of mitotic growth and another potent effect against Gram- bacteria due to increased release of β-defensin 2 peptide by macrophages. Interestingly, the needed concentrations of CIO to inhibit bacteria growth and to promote wound healing are lower than concentrations exhibiting cytotoxic effects on keratinocyte cells. Finally, we performed bioautography assay against Staphylococcus aureus to determine polarity profile of the components responsible for CIO antibacterial activity. Our results showed for the five tested CIO that components responsible of the bacterial growth inhibition are the more polar one on the TLC chromatographic profile and are contained in the resinous fraction of the oil. CONCLUSIONS This study was conducted to evaluate cytotoxicity, wound healing and antibacterial properties of five CIO traditionally used to treat infected wounds. Using cell and bacteria cultures, we confirmed the pharmacological effects of CIO as wound healing and antimicrobial agent. Moreover, we showed that concentration of CIO needed to exhibit therapeutic effects are lower than concentrations exhibiting cytotoxic effects in vitro. For the first time, this study provides support for traditional uses of CIO. These wound healing and antibiotic properties make CIO a valuable candidate to treat infected wounds especially in tropical areas.
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Affiliation(s)
- Teddy Léguillier
- Laboratoire Chimie-Toxicologie Analytique et Cellulaire-UMR CNRS COMETE 8638, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Marylin Lecsö-Bornet
- Laboratoire Ecosystème Intestinal, Probiotiques, Antibiotiques-EA 4065, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Christelle Lémus
- Laboratoire de Pharmacognosie-UMR CNRS COMETE 8638, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | | | - Nicolas Lebouvier
- Laboratoire Insulaire du Vivant et de l'Environnement-EA 4243, Université de la Nouvelle-Calédonie, Nouméa, Nouvelle Calédonie, France
| | - Edouard Hnawia
- Laboratoire Insulaire du Vivant et de l'Environnement-EA 4243, Université de la Nouvelle-Calédonie, Nouméa, Nouvelle Calédonie, France
| | - Mohammed Nour
- Laboratoire Insulaire du Vivant et de l'Environnement-EA 4243, Université de la Nouvelle-Calédonie, Nouméa, Nouvelle Calédonie, France
| | - William Aalbersberg
- Institute of Applied Sciences, University of the South Pacific, Laucala Campus, Suva, Fiji
| | - Kamelia Ghazi
- Centre de recherche de BioMécanique et BioIngénierie-CNRS UMR 7338, Université de Technologie de Compiègne, Compiègne, France
| | - Phila Raharivelomanana
- Equipe Etude Intégrée des Métabolites Secondaires-UMR 241 EIO, Université de la Polynésie Française, Tahiti, FAA'A, Polynésie Française
| | - Patrice Rat
- Laboratoire Chimie-Toxicologie Analytique et Cellulaire-UMR CNRS COMETE 8638, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
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Léguillier T, Vandormael-Pournin S, Artus J, Houlard M, Picard C, Bernex F, Robine S, Cohen-Tannoudji M. Omcg1 is critically required for mitosis in rapidly dividing mouse intestinal progenitors and embryonic stem cells. Biol Open 2012; 1:648-57. [PMID: 23213458 PMCID: PMC3507298 DOI: 10.1242/bio.20121248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent studies have shown that factors involved in transcription-coupled mRNA processing are important for the maintenance of genome integrity. How these processes are linked and regulated in vivo remains largely unknown. In this study, we addressed in the mouse model the function of Omcg1, which has been shown to participate in co-transcriptional processes, including splicing and transcription-coupled repair. Using inducible mouse models, we found that Omcg1 is most critically required in intestinal progenitors. In absence of OMCG1, proliferating intestinal epithelial cells underwent abnormal mitosis followed by apoptotic cell death. As a consequence, the crypt proliferative compartment of the small intestine was quickly and totally abrogated leading to the rapid death of the mice. Lack of OMCG1 in embryonic stem cells led to a similar cellular phenotype, with multiple mitotic defects and rapid cell death. We showed that mutant intestinal progenitors and embryonic stem cells exhibited a reduced cell cycle arrest following irradiation, suggesting that mitotic defects may be consecutive to M phase entry with unrepaired DNA damages. These findings unravel a crucial role for pre-mRNA processing in the homeostasis of the small intestine and point to a major role of OMCG1 in the maintenance of genome integrity.
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Affiliation(s)
- Teddy Léguillier
- Institut Pasteur, Unité de Génétique Fonctionnelle de la Souris, Département de Biologie du Développement , 25 rue du docteur Roux, F-75015 Paris , France ; CNRS URA 2578, F-75015 Paris , France
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Houlard M, Artus J, Léguillier T, Vandormael-Pournin S, Cohen-Tannoudji M. DNA-RNA hybrids contribute to the replication dependent genomic instability induced by Omcg1 deficiency. Cell Cycle 2011; 10:108-17. [PMID: 21191184 DOI: 10.4161/cc.10.1.14379] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
During S phase, the replisome has to overcome many physical obstacles that can cause replication fork stalling and compromise genome integrity. Transcription is an important source of replicative stress and consequently, maintenance of genome integrity requires the protection of chromosomes from the deleterious effects arising from the interaction between nascent RNAs and template DNA, leading to stable DNA-RNA hybrids (R-loop) formation. We previously reported the essential role of Omcg1 (Ovum Mutant Candidate Gene) for cell cycle progression during early embryonic development. Here, we show that OMCG1 is a target of the cell cycle checkpoint kinases ATR/ATM and is essential for S phase progression in mouse embryonic fibroblasts. Using a conditional gene inactivation strategy, we demonstrate that OMCG1 depletion impairs cell viability as a consequence of DSB formation, checkpoint activation and replication fork collapse. We also show that no chromosome breaks were generated in non-cycling Omcg1-deficient cells. Furthermore, increased RNaseH expression significantly alleviated genomic instability in deficient fibroblasts suggesting that cotranscriptional R-loops formation contributes to the genesis of replication-dependent DSBs in these cells. Together with recent reports describing its participation to complexes involved in cotanscriptional processes, our results suggest that OMCG1 plays a role in the tight coupling between mRNA processing pathways and maintenance of genome integrity during cell cycle progression.
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Affiliation(s)
- Martin Houlard
- Institut Pasteur, Unité de Génétique Fonctionnelle de la Souris, Département de Biologie du Développement, CNRS URA 2578, Paris, France
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