UMR9187 / U1196 – Chimie, modélisation et imagerie pour la biologie

Publications de l’unité

Année de publication : 2018

Xiao Xie, Oksana Reznichenko, Ludovic Chaput, Pascal Martin, Marie-Paule Teulade-Fichou, Anton Granzhan (2018 Jun 8)

Topology-Selective Fluorescent « Light-Up » Probes for G-Quadruplex DNA Based on Photoinduced Electron Transfer.

Chemistry (Weinheim an der Bergstrasse, Germany) : Accepted manuscript : DOI : 10.1002/chem.201801701 En savoir plus
Résumé

Six novel probes were prepared by covalent attachment of a G4-DNA ligand (PDC) to various coumarin or pyrene fluorophores. In the absence of DNA, the fluorescence of all probes is quenched due to intramolecular photoinduced electron transfer (PET) evidenced by photophysical and electrochemical studies, molecular modeling and DFT calculations. All probes demonstrate similarly high thermal stabilization of various G4-DNA substrates belonging to different folding topologies, as assessed by fluorescence melting experiments; however, their fluorimetric response is strongly heterogeneous with respect to structures of the probes and G4-DNA targets. Thus, the probes containing the 7-diethylaminocoumarin fluorophore demonstrate significant fluorescence enhancement in the presence of G4-DNA, with the strongest « light-up » response (20- to 180-fold) observed for antiparallel G4 structures as well as for hybrid G4 structures, formed by the variants of human telomeric sequence and capable of a conformation change to the antiparallel isoform. These results shed light on the influence of the linker and electronic properties of fluorophores on the efficiency of G4-DNA « light-up » probes operating via PET.

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M Lupu, Ph Maillard, J Mispelter, F Poyer, C D Thomas (2018 Jun 2)

A glycoporphyrin story: from chemistry to PDT treatment of cancer mouse models.

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology : Advance Article : DOI : 10.1039/c8pp00123e En savoir plus
Résumé

Photodynamic therapy (PDT) represents a non-toxic and non-mutagenic antitumor therapy. The photosensitizer’s (PS) chemo-physical properties are essential for the therapy, being responsible for the biological effects induced in the targeted tissues. In this study, we present the synthesis and development of some glycoconjugated porphyrins based on lectin-type receptor interaction. They were tested in vitro for finally choosing the most effective chemical structure for an optimum antitumor outcome. The most effective photosensitizer is substituted by three diethylene glycol α-D-mannosyl groups. In vivo studies allow firstly the determination of some characteristics of the biological processes triggered by the initial photochemical activation. Secondly, they make it possible to improve the therapeutic protocol in the function of the structural architecture of the targeted tumor tissue.

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Aaron Mendez-Bermudez, Liudmyla Lototska, Serge Bauwens, Marie-Josèphe Giraud-Panis, Olivier Croce, Karine Jamet, Agurtzane Irizar, Macarena Mowinckel, Stephane Koundrioukoff, Nicolas Nottet, Genevieve Almouzni, Mare-Paule Teulade-Fichou, Michael Schertzer, Mylène Perderiset, Arturo Londoño-Vallejo, Michelle Debatisse, Eric Gilson, Jing Ye (2018 May 5)

Genome-wide Control of Heterochromatin Replication by the Telomere Capping Protein TRF2.

Molecular cell : 449-461.e5 : DOI : S1097-2765(18)30267-3 En savoir plus
Résumé

Hard-to-replicate regions of chromosomes (e.g., pericentromeres, centromeres, and telomeres) impede replication fork progression, eventually leading, in the event of replication stress, to chromosome fragility, aging, and cancer. Our knowledge of the mechanisms controlling the stability of these regions is essentially limited to telomeres, where fragility is counteracted by the shelterin proteins. Here we show that the shelterin subunit TRF2 ensures progression of the replication fork through pericentromeric heterochromatin, but not centromeric chromatin. In a process involving its N-terminal basic domain, TRF2 binds to pericentromeric Satellite III sequences during S phase, allowing the recruitment of the G-quadruplex-resolving helicase RTEL1 to facilitate fork progression. We also show that TRF2 is required for the stability of other heterochromatic regions localized throughout the genome, paving the way for future research on heterochromatic replication and its relationship with aging and cancer.

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Ana Vujic, Carolin Lerchenmüller, Ting-Di Wu, Christelle Guillermier, Charles P Rabolli, Emilia Gonzalez, Samuel E Senyo, Xiaojun Liu, Jean-Luc Guerquin-Kern, Matthew L Steinhauser, Richard T Lee, Anthony Rosenzweig (2018 Apr 27)

Exercise induces new cardiomyocyte generation in the adult mammalian heart.

Nature communications : 1659 : DOI : 10.1038/s41467-018-04083-1 En savoir plus
Résumé

Loss of cardiomyocytes is a major cause of heart failure, and while the adult heart has a limited capacity for cardiomyogenesis, little is known about what regulates this ability or whether it can be effectively harnessed. Here we show that 8 weeks of running exercise increase birth of new cardiomyocytes in adult mice (~4.6-fold). New cardiomyocytes are identified based on incorporation of N-thymidine by multi-isotope imaging mass spectrometry (MIMS) and on being mononucleate/diploid. Furthermore, we demonstrate that exercise after myocardial infarction induces a robust cardiomyogenic response in an extended border zone of the infarcted area. Inhibition of miR-222, a microRNA increased by exercise in both animal models and humans, completely blocks the cardiomyogenic exercise response. These findings demonstrate that cardiomyogenesis can be activated by exercise in the normal and injured adult mouse heart and suggest that stimulation of endogenous cardiomyocyte generation could contribute to the benefits of exercise.

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