Typologie d'actualités: Team Chemistry, Imaging and Exobiology

CBM doctoral student wins prize for best oral presentation at symposium

Petra Cutuk, doctorante au CBM, a reçu le prix de la meilleure présentation orale lors du colloque 2025 du Réseau Molécules Marines, Métabolisme et Cancer.

Petra Cutuk, doctorante de deuxième année, qui effectue son travail de recherche conjointement entre l'équipe "Composés luminescents de lanthanides, spectroscopie et bioimagerie optique" du CBM d'Orléans et l'équipe Inserm "U1069 - Niche, Nutrition, Cancer & métabolisme Oxydatif- N2Cox" de l'Université de Tours, a reçu le prix de la meilleure présentation orale pour sa présentation intitulée "Elucidating the Regulation of SKCa Channels by the cAMP/PKA Pathway in Cancer Cells: Innovations in Near-Infrared Optical Imaging Agents" lors du colloque annuel 2025 du Réseau Molécules Marines, Métabolisme & Cancer à Mansigné le 16 mai 2025.

The prize is awarded by the Fondation ARC pour la recherche sur le cancer to finance participation in a conference.

Petra Cutuk is on the right in the photo.

 

Combination of nanomedicine and biophysics methods to characterize mRNA liposomes

This new optimised version of liposomes has been reported by CNRS Chimie on its website.

The development of lipid-based mRNA delivery systems has significantly advanced mRNA-based therapies. Liposomes, in particular histidylated liposomes (LYX), have been shown to be effective in delivering nucleic acids. In this study, LYX liposomes were optimised by adding a freeze-drying and extrusion step, resulting in improved homogeneity and storage stability. LYX liposomes maintained their size (150 ± 10 nm) and polydispersity index (0.10 ± 0.02) for up to a year at 4°C, while preserving their transfection efficiency. They exhibit a high mRNA encapsulation rate (∼95%) and protect it from degradation by RNases. The lamellar organisation was confirmed by small-angle X-ray scattering and CryoTEM. These liposomes allow efficient transfection of cell lines and primary cells, albeit with lower efficiency than commercial vectors, due to slower cell internalisation and reduced endosomal escape. They have demonstrated their ability to deliver mRNA encoding the therapeutic molecules BMP2 and BMP9, leading to the production of functional proteins capable of inducing BMP signalling. In vivo studies have also confirmed their potential for mRNA delivery when incorporated into hydrogels and implanted subcutaneously in mice. These results show that LYX liposomes are a promising and versatile platform for mRNA delivery in therapeutic applications.

This work involved laboratories from two institutes: the Centre de Biophysique Moléculaire (CNRS Chimie) and the Laboratoire de Biologie, Bioingénierie et Bioimagerie Ostéo-Articulaires (CNRS Ingénierie).

Reference:
Albert Ngalle Loth, Manon Maroquenne, Ayoub Medjmedj, Franck Coste, Thomas Bizien, Chantal Pichon, Delphine Logeart-Avramoglou, Federico Perche.
Structural and functional characterization of a histidylated liposome for mRNA deliveryStructural and functional characterization of a histidylated liposome for mRNA delivery.
Journal of Controlled Release (2025) Volume 379, pages 164-176, doi: 10.1016/j.jconrel.2025.01.010.

‘Etonnante Chimie’ (Amazing Chemistry): a CBM chemistry team welcomed secondary school students from Tours

Following the publication of the book “ Etonnante Chimie ” and as part of the project “ Etonnante chimie pour un grand oral percutant ” (“Amazing Chemistry for a Successful Oral Exam”), the “Metal complexes and MRI” team, led by Dr Eva Jakab Toth and Célia Bonnet, has been welcoming, for 4 consecutive years, first-year high school students from the Vaucanson high school in Tours.

Improved protocol for metabolite extraction and identification of respiratory quinones in extremophilic Archaea grown on mineral materials.

We investigated the metabolome of the iron- and sulfur-oxidizing, extremely thermoacidophilic archaeon Metallosphaera sedula grown on mineral pyrite (FeS2). The extraction of organic materials from these microorganisms is a major challenge because of the tight contact and interaction between cells and mineral materials. Therefore, we applied an improved protocol to break the microbial cells and separate their organic constituents from the mineral surface, to extract lipophilic compounds through liquid–liquid extraction, and performed metabolomics analyses using MALDI-TOF MS and UHPLC-UHR-Q/TOF. Using this approach, we identified several molecules involved in central carbon metabolism and in the modified Entner-Doudoroff pathway found in Archaea, sulfur metabolism-related compounds, and molecules involved in the adaptation of M. sedula to extreme environments, such as metal tolerance and acid resistance. Furthermore, we identified molecules involved in microbial interactions, i.e., cell surface interactions through biofilm formation and cell–cell interactions through quorum sensing, which relies on messenger molecules for microbial communication. Moreover, we successfully extracted and identified different saturated thiophene-bearing quinones using software for advanced compound identification (MetaboScape). These quinones are respiratory chain electron carriers in M. sedula, with biomarker potential for life detection in extreme environmental conditions.

Reference :
Gfellner SV, Colas C, Gabant G, Groninga J, Cadene M, Milojevic T. Improved protocol for metabolite extraction and identification of respiratory quinones in extremophilic Archaea grown on mineral materials. Front Microbiol. 2025 Jan 8;15:1473270. doi: 10.3389/fmicb.2024.1473270

Will it be possible to soon detect copper by non invasive imaging?

In this work, in collaboration with chemists from the Institut de Chimie de Strasbourg (CNRS/Université de Strasbourg), we have designed and studied a smart MRI probe; which is switched on in the presence of copper. The design of such probes is a real challenge as free Cu(II) in vivo is present in very low quantities, typically lower than Zn(II), another physiological cation. It is therefore of prime importance to conceive probes with a maximal turn on response in the presence of Cu(II), and an excellent selectivity towards Zn(II). The probes are typically composed of an MRI active site, a linker and a Cu(II) binding site. The use of small complexing units for Cu(II) binding makes it very difficult to obtain a good selectivity. Here, we have used a bioinspired approach where the Cu(II) binding site is based on the ATCUN motif, a small peptide that binds Cu(II) in the blood. Thanks to this design, the probe displays an unprecedented turn on response, and importantly an excellent selectivity for Cu(II) vs Zn(II). Phantom MRI images obtained closed to physiological conditions show a bright contrast, illustrating the potential of such probes.

Reference :
A Bioinspired Cu2+-Responsive Magnetic Resonance Imaging Contrast Agent with Unprecedented Turn-On Response and Selectivity
Katharina Zimmeter, Agnès Pallier, Bertrand Vileno, Martina Sanadar, Frédéric Szeremeta, Carlos Platas-Iglesias, Peter Faller, Célia S. Bonnet and Angélique Sour
Inorganic Chemistry - Vol 63 - Issue 49 - 23067−23076