Élaboration d'un protocole informatique simple et versatile permettant la modélisation exacte et précise de super-hélices[alpha] à brins et orientations multiples et à structure primaire variable

Les études de protéomique fonctionnelle nous indiquent que probablement aucune protéine n'accomplit une activité biologique ou acquiert sa conformation active de façon complètement autonome. La fonctionnalité des protéines est donc acquise via les interactions protéine-protéine. Pensons par exemples aux interactions protéine-protéine impliquées dans les cascades de signalisation cellulaire, aux complexes de transcription, de traduction etc. Vu la réelle importance des interactions protéine-protéine, la recherche en biologie est présentement en mouvance vers un nouveau courant, soit l'étude des interactions protéiniques ou l'interactomique. Les interactions inter protéine impliquant des super-hélices ont été étudiées chez la levure et il a été avancé qu'une protéine sur 11 interagirait avec d'autres protéines en utilisant un domaine structuré en super-hélice. Plus de 5% des cadres de lecture ouvert (ORFs) du génome de la levure détiendrait l'information modulant des motifs en super-hélice. La connaissance des structures en super-hélice est importante pour le développement, selon le cas, de diverses molécules d'importance pharmacologique pouvant moduler la dynamique d'assemblage, la protection ou le maintien de ces super-hélices. Pour étudier comment les protéines interagissent entre elles via les super-hélices, nous devons étudier les caractéristiques inhérentes de ces structures. Considérant la quantité impressionnante de super-hélices dans l'interactome et la quantité non négligeable de temps nécessaire pour élucider ces structures par une approche expérimentale il est évident que nous avons besoin de méthodes efficaces, rapides, faciles d'utilisation et facilement implémentables pour obtenir les modèles structuraux de toutes les catégories de super-hélices impliquées dans l'interactome en son entier. En se basant sur des postulats analogues à ceux que H.F.C. Crick avait émis en 1953, nous avons posé comme hypothèse que de maintenir chaque brin formant la super-hélice à une distance respectant celle retrouvée dans la structure de super-hélices préalablement déterminées expérimentalement serait suffisant pour générer ces mêmes super-hélices. Afin d'évaluer notre hypothèse, nous avons créé un protocole informatique utilisant un minimum de paramètres et nous l'avons testé en générant les domaines en super-hélices de huit protéines dont les structures furent déterminées par des méthodes expérimentales. Nos modèles générés sont très similaires aux structures expérimentales correspondantes (RMSD majoritairement<1) et nous avons trouvé une excellente similitude des conformations des chaînes latérales composant l'interface. De plus, nos modèles nous permettent d'identifier une certaine dynamique spécifique aux multimères et même à des résidus précis ayant une activité biologique démontrée crucial dans l'interactomique de ces super-hélices

Glioma cell infiltration stimulated by radiation

Abstract : Purpose: Radiation induces a neuro-inflammation that is characterized by the expression of genes known to increase the invasion of cancer cells. In Fischer rats, brain irradiation increases the infiltration of cancer cells and reduced the median survival of the animals. In this study, we have determined whether these adverse effects of radiation can be prevented with the cyclooxygenase-2 (COX-2) inhibitor meloxicam. Materials and methods: Brain of Fischer rats treated or not with meloxicam were irradiated (15 Gy) and then implanted with the F98 glioma cells. The median survival of the animals, the infiltration of F98 cells, and the expression of inflammatory cytokines and pro-migration molecules were measured. Results: Meloxicam reduced by 75% the production of prostaglandin E2 (bioproduct of COX-2) in irradiated brains validating its anti-inflammatory effect. Median survival was increased to control levels by the treatment of meloxicam following brain irradiation. This protective effect was associated with a reduction of the infiltration of F98 cells in the brain, a complete inhibition of radiation-enhancement of matrix metalloproteinase-2, and a significant reduction of tumor necrosis factor α (TNF-α) and tumor growth factor β1 (TGF-β1) expression. Using invasion chambers, interleukin-1β (IL-1β) stimulated by 5-fold the invasiveness of F98 cells, but this stimulation was completely inhibited by meloxicam. This suggests that a cooperation between IL-1β and COX-2 are involved in radiation-enhancement of F98 cell invasion. Conclusions: Our results indicate the importance of reducing the inflammatory response of normal brain tissue following irradiation in an effort to extend median survival in F98 tumor-bearing rats

Microneedle arrays for brain drug delivery: the potential of additive manufacturing

For a long time, the treatment of brain diseases has been a significant challenge. Drug delivery to the brain has recently become one of the most challenging problems for patients with severe forms of central nervous system diseases. The blood–brain barrier (BBB) poses a significant challenge for drug delivery to the brain. While extensive efforts focus on finding materials to overcome the BBB for brain tumor treatment, it limits the penetration of chemotherapeutic drugs for the broader treatment of brain diseases. The oral method of drug administration has several drawbacks, such as the loss of drugs because of metabolism and gastrointestinal environmental issues. Besides, using the intravenous route to administer medicines has several disadvantages, including discomfort at the injection site, infection, bleeding, anxiety, and incompetence toward patients. Fabrication and development of microneedles to overcome the drawbacks mentioned above of traditional drug delivery methods may be a viable alternative. Drug delivery using microneedle arrays (MNAs) has recently been shown to be an effective method for delivering drugs to the brain. Different fabricating methods like three-dimensional printing could be used for the fabrication of personalized drug delivery systems, like MNAs, with precise control over spatiotemporal drug distribution. This article presents a review of using MNAs for drug delivery to the brain

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches.

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its Minimal Information for Studies of Extracellular Vesicles, which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its ‘Minimal Information for Studies of Extracellular Vesicles’, which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Assessment of radiosensitizing effect of platinum compounds for glioblastoma treatment

Glioblastoma multiforme (GBM) is the most aggressive primary tumor of the brain, taking the lives of patients 12 to 14 months from diagnosis and standard treatments. Although a large amount of information from several studies about GBM treatment is available, inconsistencies between studies (many different drugs, methods, type of tumor and research models used) cause to produce ambiguities in the analysis of these data. This thesis aims to improve treatment of GBM patients from three angles. 1) The choice of chemotherapy used. We chose to use platinum compounds (Pt) in our studies because several of these compounds are already used in clinic (cisplatin, carboplatin and oxaliplatin) or in clinical study phase (Lipoplatin and Lipoxal). The Pt are also known to be good radiosensitizers. The five selected Pt were first tested in vitro on a murine glioblastoma cell line, F98 cells. These in vitro studies have shown the comparative effectiveness of each Pt used alone or combined with ionizing radiation. In addition to the radiosensitizer potential of Pt, we also aim to reduce the systemic toxicity in vivo while increasing the preferential incorporation into the tumor. To reach these last two criteria, we tested the liposomal forms of cisplatin and oxaliplatin that are Lipoplatin and Lipoxal, respectively. 2) Demonstrate the advantage of the chemotherapy and radiotherapy combination. As mentioned earlier, Pt are good radiosensitizers, we combined chemotherapy and radiotherapy in our in vivo model that is Fischer rats bearing F98 glioma implanted in its brain. This portion of the project required the design, fabrication and control of accuracy and reproducibility of a new stereotactic frame adaptable to different components of the Gamma Knife. 3) Choice of the optimal route of administration of chemotherapy. Today, the standard clinical treatment usually consists of optimal resection of the tumor followed by chemotherapy in concomitance with ionizing radiation. Chemotherapy only brings modest improvement and is often transient in most patients with GBM. On the other hand, the Pt may allow better control of GBM if the tumor uptake of these drugs would be higher. To improve the incorporation of chemotherapy in the primary tumor, increase the concomitance effect with radiation, while simultaneously reducing systemic toxicity, this study compares the effectiveness of three different routes of administration (IV, IA and blood-brain barrier disruption (bbbd)) for the five platinum compounds.Le glioblastome multiforme (GBM) est la tumeur primaire du cerveau la plus agressive, prenant la vie des patients de 12 à 14 mois suivant le diagnostic et le traitement standard. Même si une grande quantité d'informations provenant de plusieurs études portant sur les traitements des GBM sont disponibles, les incohérences entre les études (grand nombre de médicaments différents, de méthodes, de type de tumeur et des modèles de recherche utilisés) font en sorte de produire une ambiguïté dans l'analyse de ces données. Cette Thèse a pour objectif d'améliorer les traitements des patients atteints de GBM sous trois angles. 1) Le choix de la chimiothérapie utilisée. Nous avons choisi d'utiliser des composés platinés (Pt) dans nos études, car plusieurs de ces composés sont déjà utilisés en clinique (cisplatin, oxaliplatin et carboplatin) ou en phase d'étude clinique (Lipoplatin et Lipoxal). Les Pt sont aussi reconnus pour être de bons radiosensibilisants. Les cinq Pt choisis ont d'abord été testés in vitro sur une lignée cellulaire de glioblastome murin, soit les cellules F98. Ces études in vitro nous ont montré l'efficacité anti-cancéreuse de chaque Pt employé seul ou combiné avec la radiation ionisante. En plus de l'aspect radiosensibilisant des Pt, nous avions aussi pour objectif de réduire la toxicité systémique in vivo et d'augmenter leur incorporation préférentielle dans la tumeur. Pour répondre à ces deux derniers critères, nous avons testé les formes liposomales du cisplatin et de l'oxaliplatin soit le Lipoplatin et le Lipoxal, respectivement. 2) Démontrer l'avantage thérapeutique de la combinaison chimioradiothérapie. Les Pt étant de bons radiosensibilisateurs, nous avons combiné leurs effets chimiothérapiques et la radiothérapie dans notre modèle in vivo, soit le rat Fischer porteur de glioblastome F98 implanté dans leur cerveau. Cette portion du projet a nécessité la conception, la fabrication et les contrôles de précision et de reproductibilité d'un nouveau cadre stéréotaxique adaptable aux différentes composantes du Gamma Knife (scalpel aux rayons gamma). 3) Choix de la route d'administration optimale de la chimiothérapie. Aujourd'hui, le traitement standard clinique se compose généralement d'une résection optimale de la tumeur suivie de chimiothérapie concomitante avec le rayonnement ionisant. La chimiothérapie apporte seulement un léger bénéfice et est souvent que transitoire pour la plupart des patients atteints de GBM. D'autre part, les Pt pourraient permettre un meilleur contrôle du GBM si la captation tumorale de ces médicaments était plus élevée. Afin d'améliorer l'incorporation de chimiothérapie à la tumeur primaire, augmenter l'effet concomittant avec les radiations, tout en réduisant simultanément la toxicité systémique, la présente étude compare l'efficacité de trois différentes voies d'administration (IV, IA et ouverture de la barrière hémato-encéphalique (OBHE)) pour les cinq composés platinés mentionnés