ED Sciences de la Vie et de la Santé
Study of thermo-TRP ion channels: targeting TRPV1-calmodulin coupling and exposure to 5G radiofrequency fields
by Léna SERRADEILL (Laboratoire de l'Intégration du Matériau au Système)
The defense will take place at 9h30 - Amphithéâtre Jean-Paul DOM Laboratoire IMS (Intégration du Matériau au Système) Bordeaux University - Batiment A31 351 av de la libération 33400 Talence, France
in front of the jury composed of
- Yann PERCHERANCIER - Directeur de recherche - Université de Bordeaux - Laboratoire IMS - Directeur de these
- Muriel GOLZIO - Directrice de recherche - Université de Toulouse - Institut de Pharmacologie et de Biologie Structurale, IPBS - Rapporteur
- Philippe GAILLY - Professeur - Université catholique de Louvain - Institute of Neuroscience, Laboratory of Cell Physiology - Rapporteur
- Yves LE DRéAN - Professeur - Université de Rennes - IRSET, Institut de recherche en santé, environnement et travail - Examinateur
- Vincent COMPAN - Chargé de recherche - Université de Montpellier - Institut de Génomique Fonctionnelle, IGF - Examinateur
- Isabel ALVES - Directrice de recherche - Université de Bordeaux - CBMN, Institut de Chimie et Biologie des Membranes et des Nano-objets - Examinateur
This thesis focuses on thermosensitive TRP (Transient Receptor Potential) ion channels, known as thermo-TRP channels, which are polymodal sensors involved in detecting mechanical, chemical, and thermal stimuli. It is organized around two axes centered on the functional and conformational dynamics of these channels. The first axis evaluates the potential biological effects of radiofrequencies (RF) exposure at 700 MHz, a frequency band used for fifth-generation (5G) mobile telecommunications, on three thermo-TRP channels: TRPV1, TRPV4, and TRPM8. These channels are respectively associated with the detection of heat, moderate temperatures, and cold. In response to questions regarding possible “non-thermal effects” of RF fields, the objective was to determine whether these exposures could modify the chemical and/or thermal activation of these channels. This study was performed using biosensors based on bioluminescence resonance energy transfer (BRET), enabling real-time monitoring in living cells of channel conformational changes or calcium fluxes associated with their activation. Cells were exposed to 700 MHz, either as a continuous wave or with 5G modulation, at different SAR (specific absorption rate) levels, in order to study conditions below and above the reference values used for RF exposure. The analysis of chemical activation revealed no RF-induced modification, at steady temperature, of basal calcium permeability, agonist efficacy, or channel activation kinetics. Regarding thermal activation, thermodynamic modeling of BRET trajectories measured during temperature variation cycles allowed the extraction of apparent parameters such as the critical temperature (Tc), |ΔH|, and |ΔS|. No effect was observed for TRPV4, whereas limited variations in |ΔH| and |ΔS| were detected for TRPV1 and TRPM8, without any shift in Tc. These results indicate that, under these experimental conditions, exposure to 700 MHz RF does not constitute an acute activation mode for thermo-TRP channels. Beyond this conclusion, this work highlights the value of BRET biosensors for monitoring the functional and conformational dynamics of these channels, and supports the idea that chemical and thermal stimuli modulate their activation through interconnected mechanisms. The second axis focuses on the functional role of the interaction between the TRPV1 channel and calmodulin (CaM). TRPV1 is involved in the detection and amplification of pain signals, particularly in inflammatory and neuropathic pain. Although it represents a major therapeutic target for the development of non-opioid analgesics, pharmacological strategies directly targeting its activity have been limited by major side effects, especially disturbances in thermoregulation. In this context, this thesis explores an alternative strategy based on targeting TRPV1-CaM coupling using complementary BRET biosensors. These findings suggest that CaM is not limited to its classically described role as a negative regulator of TRPV1, but may instead act as a functional subunit required for maintaining TRPV1 at the cell surface. The use of genetically encoded and then synthetic peptides mimicking different TRPV1 regions involved in the interaction with CaM showed that, for some of them, targeted disruption of TRPV1/CaM coupling leads to decreased membrane expression of the channel. The most promising peptides are currently being evaluated in vivo in a mouse model of acute thermal nociception. This work thus proposes an innovative mode of TRPV1 modulation, opening new perspectives for the development of targeted analgesic approaches.
LPCBioMab, Antibody-Functionalized Lipoprotein Complexes (LPC) including ApoA1 and a repolarising drug for the targeted therapy of atherosclerosis
by Mathilde RAGUES (Centre de Résonnance Magnétique des Systèmes Biologiques)
The defense will take place at 9h00 - Salle de conférence RMSB, 2 Rue Dr Hoffmann Martinot, 33000 Bordeaux
in front of the jury composed of
- Marie-Josée JACOBIN-VALAT - Ingénieure de recherche - Université de Bordeaux - Directeur de these
- François CANONNE-HERGAUX - Chargé de recherche - DéTROI Diabète-athérothrombose Thérapies Réunion Océan Indien U1188 - Rapporteur
- Philippe LESTNIK - Directeur de recherche - Ican – Unité de recherche sur les maladies cardiovasculaires et métaboliques - Rapporteur
- Emmanuelle TREVISIOL - Directrice de recherche - TBI Toulouse Biotechnology Institute UMR5504 - Examinateur
- Astrid MUSNIER - Directrice Scientifique - Société Mabsilico - Examinateur
- Stéphane MORNET - Directeur de recherche - Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) - Examinateur
Atherosclerosis is the leading cause of cardiovascular events, the number one cause of death worldwide. This chronic inflammatory condition is characterised by the accumulation of oxidised low-density lipoproteins (oxLDL) in the intima of medium and large-calibre arteries. These lipid deposits lead to the recruitment of circulating monocytes, which differentiate into macrophages within the intima. There, they internalise oxLDL. Macrophages therefore play a central role in the initiation, progression, and destabilisation of lesions known as atherosclerotic plaques, which are characterised by an accumulation of macrophages. Despite therapeutic advances, there is still a significant need for improved diagnostics and targeted therapies. Current strategies primarily focus on managing systemic risk factors and are insufficient to reduce the incidence of cardiovascular events. Therefore, the development of innovative approaches that directly target the key mechanisms of the disease, particularly plaque macrophages, appears necessary. In this context, my PhD project is part of an ANR project that aims to develop a nanoparticle for targeted theranostic strategies in the treatment of atherosclerosis. This nanoparticle consists of a reconstituted biomimetic HDL (HDL-like) lipoprotein complex containing functional ApoA1, as well as a therapeutic molecule capable of modulating the phenotypic plasticity of macrophages present in atherosclerotic plaques. The HDL-like particles are functionalised with fully human antibodies (HuAbs) to target plaque macrophages and antibodies that target oxidised ApoA1, which is abundant in lesions. This allows the therapeutic effect to be concentrated at vulnerable sites. Within this project, my work has focused on developing HuAbs that target plaque macrophages and studying the effect that different nanoparticle formulations (with or without an immunomodulatory molecule) have on models of primary human macrophages. To this end, I began by using antibodies that had previously been selected by phage display. Pre-screening using flow cytometry on human monocyte-derived macrophages (MDMs) enabled the top 10% most promising antibodies to be selected, and these were then reformatted into soluble forms. Their ability to recognise macrophages and atherosclerotic plaques was subsequently evaluated using flow cytometry and immunohistochemistry on human, murine, and rabbit tissue sections, respectively. In parallel, I assessed the effect of different nanoparticle formulations provided by our collaborators on MDMs that mimicked various phenotypes of macrophages present in plaques. I investigated the potential immunomodulatory effect of these nanoparticles by analysing the expression of inflammatory and immunoregulatory phenotypic biomarkers using fluorescence microscopy, as well as studying the cytokines secreted by macrophages using multiplex ELISA. This work enabled the selection of a candidate anti-macrophage antibody for functionalising the nanoparticles, as well as identifying the most promising HDL-like formulation. The results also demonstrate that this formulation containing the therapeutic molecule has an anti-inflammatory effect on macrophages, in contrast to the same formulation lacking this molecule. This research contributes to the development of an innovative tool for the diagnoses and targeted treatment of atherosclerosis, opening up promising prospects for the development of new theranostic approaches to this condition.
Transdiagnostic pathways in disordered eating: A network perspective on cognitive and affective dimensions
by Chantal DELAQUIS (Institut de neurosciences cognitives et intégratives d'Aquitaine)
The defense will take place at 14h00 - CARF Amphitheatre 146 Rue Léo Saignat 33000 Bordeaux
in front of the jury composed of
- Sylvie BERTHOZ-LANDRON - Chargée de recherche - INSERM - Directeur de these
- Marie GRALL BRONNEC - Professeure des universités - praticienne hospitalière - Faculté de Médecine de Nantes et CHU de Nantes - Rapporteur
- Arnaud CARRE - Professeur des universités - Université Savoie Mont Blanc – UFR LLSH – Département de Psychologie - Rapporteur
- Anne ROEFS - Full professor - Faculty of Psychology and Neuroscience, Maastricht University - Examinateur
Eating disorders (EDs) are devastating psychiatric conditions with few effective evidence-based treatments – only half of patients recover and 25% of those patients will relapse. Increasingly, research is shifting beyond eating and weight-related symptoms to examine broader maintenance mechanisms and improve treatment outcomes. Two leading theoretical frameworks, the cognitive-interpersonal model of anorexia nervosa (AN) and the transdiagnostic cognitive-behavioural model, proposing highly compatible, overlapping ED maintenance mechanisms including cognitive rigidity, perfectionism, contingent self-worth, emotion regulation and interpersonal difficulties. To examine the complex interactions between a wide range of symptoms, network analysis offers a uniquely suitable framework by conceptualising psychopathology as a system of interacting symptoms. This approach allows for the identification of central nodes, representing key treatment targets, as well as bridge nodes, which link symptom clusters and may drive comorbidity. Across five studies, the current thesis aims to understand the interplay between maintenance mechanisms proposed by the leading theoretical models. Chapter 3 investigates cognitive-interpersonal features among adolescent inpatients with AN to identify central and bridge symptoms. Concern over Mistakes, a dimension of perfectionism, emerged as both a central and bridge node. This symptom was significantly more central than core eating disorder symptoms. Chapter 4 extends this work to examine the network structure of cognitive-behavioural symptoms among both adult and adolescent inpatients with AN. Concern over Mistakes again emerged as a central node, alongside Overvaluation of Weight and Shape and Personal Standards, while Self-Esteem and Concern over Mistakes were bridge nodes. Further, anxiety symptoms were significantly more central in restrictive AN compared to the binge-purge subtype. Chapter 5 integrates these studies and tests their replicability modelling both cognitive-interpersonal and cognitive-behavioural features among Australian community members reporting disordered eating symptoms. Concern over Mistakes was again both a central and bridge node. Both Impulsivity/Difficulty with Goal-Directed Behaviour and Overvaluation of Weight and Shape were also central. Given the robust centrality of perfectionism, Chapter 6 examines the distinct yet complementary roles of Concern over Mistakes and Personal Standards among Australians self-reporting an ED compared to controls. Neither dimension differed between ED diagnostic groups nor ED behavioural presentations (restrictive, binge-purge and binge), supporting their transdiagnostic relevance. When controlling for anxiety and depressive symptoms, Concern over Mistakes remained elevated across all ED groups whereas the effect of Personal Standards was largely accounted for by anxiety. Lastly, Chapter 7 addresses literature gap regarding perfectionism and disordered eating among individuals with a high body weight. Following PRISMA guidelines for scoping reviews, we found that while perfectionism had no direct association with BMI, Concern over Mistakes in particular was associated with disordered eating across studies. Taken together, these findings highlight the robust, central role of Concern over Mistakes as a transdiagnostic feature of eating pathology that transcends diagnostic categories, behavioural presentations, and body weights. The consistent centrality of non-eating related symptoms across network studies challenges the assumption that EDs are defined primarily by their behavioural expression, as current diagnostic classification suggests. Our results, together with a growing body of literature, point towards a cognitive-affective and temperament-informed framework for understanding, classifying, and treating these conditions.