ABD-Derived Affinity Proteins (ADAPTs) is a novel class of small engineered scaffold proteins based on albumin-binding domain (ABD) of streptococcal protein G. High affinity ADAPT  binders against various therapeutic targets can be selected.  In this thesis, we report a development of ADAPT-based radionuclide imaging agents providing high sensitivity and specificity of molecular imaging of HER2 expression in disseminated cancers. We investigated the feasibility of the use of ADAPTs as imaging agents and influence of molecular design and radiolabeling chemistry on in vivo targeting and biodistribution properties of the tracers. In Paper I we demonstrated the feasibility of the use of anti-HER2 ADAPT6 molecule as a high contrast imaging agent; In Paper II we evaluated the influence of composition of histidine-containing tag on in vivo biodistribution of ADAPT-based tracers labeled with 99mTc using 99mTc(CO)3 binding to histidine-containing tags and 111In using DOTA chelator at N-terminus; In Paper III we evaluated the influence of different aspects of N-terminus leading sequence on targeting including effect of sequence size on clearance rate and effect of the composition of the sequence on biodistribution profile; In Paper IV, we evaluated the influence of residualizing properties and positioning of the label on biodistribution and targeting; and In Paper V, we compared tumor-targeting properties of the ADAPT6 labeled at C-terminus with 99mTc using N3S chelator and 111In using DOTA chelator. In conclusion, ADAPTs constitute a very promising class of targeting probes for molecular imaging providing high contrast. Molecular design of the ADAPT proteins and chelators/linkers for labeling has an appreciable effect on their imaging properties.

At the heart of high harmonic generation lies a combination of optical and collision physics entwined by a strong laser field. An electron, initially tunnel-ionized by the field, driven away then back in the continuum, finally recombines back to rest in its initial ground state via a radiative transition. The emitted attosecond (atto=10^-18) XUV light pulse carries all the information (polarization, amplitude and phase) about the photorecombination continuum-to-ground transition dipolar field. Photorecombination is related to the time-reversed photoionization process. In this perspective, high-harmonic spectroscopy extends well-established photoelectron spectroscopy, based on charged particle detection, to a fully coherent one, based on light characterization. The main achievement presented in this thesis is to use high harmonic generation to probe femtosecond (femto=10^-15) chemical dynamics for the first time. Thanks to the coherence imposed by the strong driving laser field, homodyne detection of attosecond pulses from excited molecules undergoing dynamics is achieved, the signal from unexcited molecules acting as the reference local oscillator. First, applying time-resolved high-harmonic spectroscopy to the photodissociation of a diatomic molecule, Br2 to Br + Br, allows us to follow the break of a chemical bond occurring in a few hundreds of femtoseconds. Second, extending it to a triatomic (NO2) lets us observe both the previously unseen (but predicted) early femtosecond conical intersection dynamics followed by the late picosecond statistical photodissociation taking place in the reaction NO2 to NO + O. Another important realization of this thesis is the development of a complementary technique to time-resolved high-harmonic spectroscopy called LAPIN, for Linked Attosecond Phase INterferometry. When combined together, time-resolved high-harmonic spectroscopy and LAPIN give access to the complex photorecombination dipole of aligned excited molecules. These achievements lay the basis for electron recollision tomographic imaging of a chemical reaction with unprecedented angstrom (1 angstrom= 0.1 nanometer) spatial resolution. Other contributions dedicated to the development of attosecond science and the generalization of high-harmonic spectroscopy as a novel, fully coherent molecular spectroscopy will also be presented in this thesis.

ToF-SIMS imaging has been drawing attention due to the wide range of applications in the biological and biomedical fields. These applications include the acquisition of quantitative and qualitative data that ranges in scale from single cells to organs, image visualisation and interpretation of biomarkers for diagnosis and development of pharmaceutics. This study focused on molecular imaging of mouse brain tissue sections using cluster primary ion beams. First, cluster ion beams were applied to comparative background studies of biomolecules and brain total lipid extract. Enhancement of the secondary ion signal was observed using water-containing cluster primary ion beams, especially for [M+H]+ type secondary ions. Water-containing clusters were then used to acquire ToF-SIMS images from the cerebellar area of serial mouse brain tissue sections. Again, water-containing cluster beams produced the highest secondary ion yields in both grey and white matter, gaining a new level of insight into the lipid compositions of both types of tissue in the brain. A clinical case was also evaluated with ToF-SIMS imaging, using cluster beams for the analysis of 3xTg-AD mouse brain tissue. SIMS images were registered with fluorescence microscopy images for the in situ identification and co-localisation of the Amyloid-β plaques on the SIMS images. Spectra from regions of interest were analysed to identify possible ion fragments derived from the Aβ protein. The co-localisation of cholesterol was also studied from images obtained with different primary ion beams. The results presented show that cluster ToF-SIMS can be successfully applied to brain tissue imaging. New primary ion beam technologies allow us to acquire data with more useful secondary ion yield for clinical applications and biological research. Nevertheless, future technological improvements are required for specialised applications e.g. cellular imaging. Moreover, processing the data obtained is still challenging and more data processing tools are also needed for interpretation.

La neuroinflammation joue un rôle important dans de nombreuses maladies neurodégénératives telles que la maladie d’Alzheimer, Parkinson, ou encore la sclérose en plaques. De récents développements en imagerie moléculaire permettent aujourd’hui un meilleur diagnostique et un meilleur suivi thérapeutique de ces maladies. Parmi les techniques d’imagerie dont nous disposons actuellement, la Tomographie par Emission de Positions (TEP) et Tomographie par Emission Mono Photonique (TEMP) jouent un rôle important de par leur haute sensibilité et leurs aspects quantitatifs. L’objectif de ma thèse est de développer de nouveaux ligands et radioligands dédiés à l’imagerie de cibles spécifiques impliquées dans les processus de neuroinflammation. Pour ce faire, la TEP et ses émetteurs de positons à vie brève associés (notamment le fluor-18 ; T1/2 : 109.8 min) constituent un outil de choix. Le projet est divisé en deux sections principales. La première est dédiée au développement de ligands ciblant la protéine de Translocation 18 kDa (TSPO). Cette protéine est aujourd’hui reconnue comme un biomarqueur précoce des processus neuroinflammatoires, et de nombreux ligands ont déjà été synthétisés pour cette cible. Le plus anciens d’entre eux est le PK11195 appartenant à la famille des isoquinoléines, qui a été marqué au carbone-11 à la fin des années 80. Plus récemment, d’autres familles de composés ont vu le jour, et notamment la familles des pyrazolopyrimidines avec le [11C]DPA-713, ainsi que celle des pyridazinoindoles avec le [11C]SSR180575. A travers cette première partie de ma thèse, l’objectif est de synthétiser et de caractériser in vitro de nouveaux ligands dérivés des deux composés leaders de ces deux familles. Les précurseurs de marquage correspondant ont également été synthétisés pour les composés les plus prometteurs, permettant ainsi un radiomarquage au fluor-18. Certains résultats ont par ailleurs été présentés lors d’un congrès international (21st International Symposium on Radiopharmaceutical Sciences (Columbia, MO, USA – Mai 26-31, 2015)). La seconde partie de ma thèse est dédiée au développement de ligands pour des cibles alternatives à la TSPO, qui sont les récepteurs cannabinoïdes de type 2 (CB2R), et les récepteurs purinergiques P2Y12 et P2Y14. Ces nouvelles cibles, récemment émergées présentent un fort potentiel pour de nouvelles opportunités en imagerie. Une nouvelle série de sept composés a par ailleurs déjà été synthétisée en ce qui concerne le CB2R. Les précurseurs des molécules les plus prometteuses ont également été préparés. La synthèse des ligands dédiés aux récepteurs purinergiques a été initiée, et un premier couple référence /précurseur a été obtenu. / Neuroinflammation plays an important role in many neurodegenerative diseases (Alzheimer, Parkinson, Multiple sclerosis …) and recent developments in molecular imaging provide today new insights into the diagnostic and the treatement managment of these diseases. Among the existing imaging techniques, the highly sensitive and quantitative nuclear modalities SPECT (single photon emission computed tomography) but especially PET (positron emission tomography) play key roles. My PhD program is devoted to the design and synthesis of novel radioligands, all dedicated to the imaging of specific targets and processes linked to neuroinflammation. For this, PET and the short-lived positron-emitter fluorine-18 (T1/2: 109.8 min) remain the main focuses. The project has been divided into two sections, the first one concentrates on the development of novel ligands targeting the Translocator Protein 18 kDa (TSPO). Indeed, this target is today recognized as an early biomarker of neuroinflammatory processes and PK11195, an isoquinoline carboxamide labelled with carbon-11, was, in the late 80’s, the first reported PET-radioligand. More recently, new compounds, all belonging to different chemical classes, have emerged and notably the pyrazolopyrimidine acetamide [11C]DPA-713 and the pyridazinoindole acetamide [11C]SSR180575. Within the first section of my PhD, novel derivatives of both DPA-713 and SSR180575 have been synthesized and in vitro characterized. Dedicated precursors for labelling were also developed for the most promising candidates, and radiolabelling has been performed. Some results have been presented at the 21st International Symposium on Radiopharmaceutical Sciences (Columbia, MO, USA – May 26-31, 2015).The second part of my PhD, deals with the development of ligands for alternative targets to the TSPO, like the type-2 cannabinoid receptor (CB2R) and the purinergic P2Y14 / P2Y12 receptors, the latter emerging today as a hot topic for imaging opportunities. Up to now, a series of seven compounds targeting the CB2R has been successfully synthetized and in vitro characterized. Dedicated precursors of the most promising compounds have also been prepared and labelling will be shortly performed. The synthesis of ligands targeting the purinergic receptors has also been initiated and a first couple of reference / precursor has been obtained for the P2Y12R.

Le but du projet est le développement de nouvelles techniques d’imagerie pour le diagnostic et le traitement du cancer du rein. Nous avons évalué différentes techniques comprenant la tomographie en cohérence optique et l’imagerie moléculaire. Nous avons évalué différents marqueurs potentiels pour l’imagerie moléculaire en étudiant l’expression de différents marqueurs dans le cancer du rein et leur association avec le pronostic de la maladie. Enfin, nous avons évalué deux techniques d’imagerie moléculaire sur des modèles précliniques : l’Imagerie par Résonnance Magnétique moléculaire et l’échographie moléculaire. / The aim of this project is the development of new imaging techniques for renal cancer diagnostic and treatment.We have assessed several techniques including optical coherence tomography and molecular imaging. We assessed a series of potential markers for molecular imaging by measuring some pre-defined markers expressions by immunohistochemistry in renal cell carcinoma and their association with disease’s prognostic. Finally, we assessed two molecular imaging techniques in pre-clinical models: Molecular Magnetic Resonance Imaging and Molecular Ultrasound Imaging.

In this Thesis, structure and dynamics of paramagnetic complexes for medical application are studied by Nuclear Magnetic Resonance (NMR). It focuses mainly on development of contrast agents (CA) for Magnetic Resonance Imaging (MRI) which is one of the most effective radiodiagnostic method nowadays. Most of the MRI CAs contains paramagnetic complexes of d- and f-metal ions. The presence of unpaired electron in proximity of NMR active nuclei has two main effects: paramagnetically induced shift and paramagnetically induced relaxa- tion. Both processes can dramatically change the NMR spectrum and often make it unobservable at all. Nevertheless, in many cases, acquisition of such spectra is possible and sometimes even less time-consuming than observation of diamag- netic molecules. Enhanced T1 relaxation allows faster pulse sequence repetition and increased chemical shift dispersion may lead to resolution of originally over- lapped signals. Moreover, the analysis of paramagnetic effects can provide useful information about the structure and dynamics of the studied system. Theoretical background of these effects is described in the Introduction of the Thesis. In the first part of Discussion in the Thesis, a new class of contrast agents for 19F-MRI based on nickel(II) and cobalt(II/III) ions is introduced...

Ces travaux de thèse s'inscrivent dans le contexte de l'imagerie moléculaire, qui vise à adapter les traitements de pathologies à la variabilité de chaque patient, grâce à l'imagerie de biomarqueurs cellulaires ou moléculaires. En particulier, l'imagerie par résonance magnétique (IRM) couplée a des nanoparticules d’oxyde de fer innovantes pourrait permettre de relever un tel défi.Cette thèse se concentre sur l'étude d'une nouvelle classe d'agents de contraste à base d'oxyde de fer pour l'IRM à haut champ magnétique. En effet, les magnétosomes sont des vésicules d’oxyde de fer produites naturellement par des bactéries appelées bactéries magnétotactiques. De telles bactéries synthétisent ces vésicules magnétiques et les alignent comme l'aiguille d'une boussole, ce qui facilite leur navigation dans les sédiments. Ces bactéries produisent donc des magnétosomes aux propriétés magnétiques exceptionnelles: 50 nm de diamètre, mono-cristallin, mono-domaine magnétique et avec une haute magnétisation à saturation. De plus, une grande variété de souches bactériennes existent dans la nature, et produisent, avec une grande stabilité, des magnétosomes dont la taille, la forme, et le contenu chimique, sont déterminés génétiquement. Enfin, les magnétosomes sont naturellement porteurs d'une membrane bi-lipidique dont le contenu est également déterminé génétiquement. Récemment, le contenu protéique de la membrane des magnétosomes a été mis à jour, ouvrant la voie à la fonctionnalisation de cette dernière par fusion des gènes codant pour des protéines présentes abondamment à la membrane avec ceux codant pour un peptide d’intérêt.Ainsi, l'utilisation de ces micro-organismes pour produire des agents de contraste innovants et fonctionnalisés pour l'imagerie moléculaire par IRM, et les applications qui en découlent, ont été étudiées pendant cette thèse. La production et l'ingénierie des magnétosomes a été réalisée par nos collègues du Laboratoire de Bioénergétique Cellulaire (LBC, CEA Cadarache), et sera présentée et discutée. Des magnétosomes sauvages ont d'abord été caractérisés en tant qu'agents de contraste pour l'IRM. De tel magnétosomes présentent des propriétés contrastantes très intéressantes pour l'IRM, ce qui a été validé à la fois in vitro puis in vivo. L'étude de faisabilité de la production d'un agent de contraste pour l'imagerie moléculaire par IRM en une seule étape, à l'aide des bactéries magnétotactiques, a été réalisée sur un modèle de souris porteur de glioblastome. Sachant par la littérature que les cellules tumorales sur-expriment les intégrines anb3, et que ces dernières peuvent être ciblées par le peptide RGD, il a été choisi de produire des magnétosomes exprimant le peptide RGD à leur membrane. L'affinité de tels magnétosomes pour les cellules tumorales U87 a été vérifiée in vitro, et démontré in vivo par IRM puis cross-validé par histologie. / This work takes place in the context of molecular imaging, which aims at tailoring medical treatments and therapies to the individual context by revealing molecular or cellular phenomenon of medical interest in the less invasive manner. In particular, it can be acheived with MRI molecular imaging using engineered iron-oxide contrast agent.This PhD thesis focuses on the study of a new class of iron-oxide contrast agent for high field MRI. Indeed, magnetosomes are natural iron-oxide vesicles produced by magnetotactic bacteria. These bacteria synthesized such magnetic vesicles and ordered them like a nano-compass in order to facilitate their navigation in sediments. This explains why magnetosomes are awarded with tremendous magnetic properties: around 50 nm, mono-crystalline, single magnetic domain and high saturation magnetization. Furthermore, a wide variety of bacterial strains exist in nature and size and shape of magnetosomes are highly stable within strain and can be very different between strains. Finally, magnetosomes are naturally coated with a bilipidic membrane whose content is genetically determined. Lately, researchers have unravelled magnetosomes membrane protein contents, opening the way to create functionnalized magnetosomes thanks to fusion of the gene coding for a protein of interest with the gene coding for an abundant protein at magnetosomes membrane.A new alternative path using living organisms to tackle the production of engineered high effciency molecular imaging probes have been investigated with magnetotactic bacteria in this PhD. The production and engineering of magnetosomes have been carried out by our partner, the Laboratoire de Bio-energétique Cellulaire (LBC, CEA Cadarache), and will be presented and discussed. We then characterized magnetosomes as contrast agent for high field MRI. We showed they present very promising contrasting properties in vitro, and assessed this observation in vivo by establishing they can be used as effcient blood pool agent after intravenous injection. Afterward, we applied the concept of producing engineered MRI molecular imaging probes in a single step by bacteria, to a mouse model of glioblastoma. Knowing that tumor cells can be actively targeted through anb3 integrins by RGD, we produced RGD functionnalized magnetosomes. We started from showing these RGD magnetosomes have a good affnity for U87 cell in vitro, prior to demonstrate it in vivo on orthotopic U87 mouse model. This in vivo affnity being fnally cross-validated with histology.

Die Diagnostik von Kardiovaskulären Erkrankungen erfolgt vorwiegend mit unspezifischen Methoden, die keine molekularen Informationen über das Gefäß liefern. Die molekulare Bildgebung könnte eine präzisere Diagnose ermöglichen. Ein geeigneter Biomarker für die molekulare Diagnostik von Erkrankungen der Aorta ist das Proteoglycan-spaltende Enzym ADAMTS4 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs), welches von Zellen im erkrankten Gewebe von Aorten überexprimiert wird. Insbesondere für die Magnetresonanztomographie (MRT) haben sich Peptide als geeignete Binder für die molekulare Bildgebung erwiesen. In dieser Arbeit wurde eine bestehende Screening-Methode, durch cyclische, hexamere Peptide einer One-Bead-One-Compound (OBOC)-Bibliothek erweitert. Die Cyclisierung erfolgte über eine Disulfidbrücke zwischen zwei Cysteinen. Ein Abbruchsequenzspektrum ermöglichte die Sequenzierung mittels Matrix-unterstützter Laser Desorption/Ionisation-Flugzeit-Massenspektrometrie (MALDI-ToF-MS). In einem Screening gegen ADAMTS4 konnten cyclische Peptide gefunden werden und mittels Oberflächenplasmonenresonanz (SPR) charakterisiert. Die Sequenz C*-S-A-A-G-C* zeigte jeweils die selektivste und stärkste Bindung gegen ADAMTS4. In einer Bindungsstudie mit Microscale Thermophoresis (MST)-Spektroskopie zeigte das Peptid eine für die molekulare MR-Bildgebung vorteilhafte, selektive Affinität von (50 ± 20) nM gegenüber ADAMTS4. Die Peptidsequenz wurde mit einem Spacer und einem MRT-aktiven Gadolinium(III)-DOTA-Komplex gekoppelt und zeigte in vitro keine Toxizität. Die Sonde wurde in vivo in einem abdominalen Aortenaneurysma-Modell untersucht. Der Anstieg des Kontrast-zu-Rausch-Verhältnisses (CNR, Contrast-to-Noise Ratio) ermöglichte die Unterscheidung zwischen erkrankten und nicht erkrankten Tieren. Zusätzlich konnte bereits in einem frühen Stadium das Rupturrisiko abgeschätzt und eine tödliche Aorten-Ruptur vorhergesagt werden. / Currently, the diagnosis of cardiovascular diseases is performed with unspecific methods, which do not provide any molecular information about the condition of the vessel wall. Molecular imaging could fill the gap and offer a more precise diagnosis. The proteoglycan-cleaving enzyme ADAMTS4 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs) could be used as a biomarker for molecular imaging of aneurysm and atherosclerosis, since it is highly upregulated in the unstable course of cardiovascular diseases. Especially for magnetic resonance imaging (MRI), peptide probes have been proven to be suitable for contrast increase of vessel diseases. In this work, a screening technique was optimized and upgraded for the use of cyclic, hexameric One-Bead-One-Compound (OBOC)-libraries. The cyclisation was performed via a disulfide bridge between two cysteines. A ladder sequence was used for sequencing by Matrix-Assisted Laser Desorption/Ionisation-Time of Flight-Mass Spectrometry (MALDI-ToF-MS). In a high throughput screening against ADAMTS4 several peptides were found and classified by their interaction against ADAMTS4 with Surface Plasmon Resonance (SPR). The peptide with the sequence C*-S-R-R-G-C* showed not only the highest selectivity against ADAMTS4 in the screening, but also the strongest interaction in the SPR. In a binding assay by Microscale Thermophoresis (MST), the peptide had a favorable and selective affinity against ADAMTS4 of (50 ± 20) nM. The peptide was extended by a short peptide spacer and a magnetic resonance (MR) active gadolinium(III)-DOTA complex and showed no in vitro toxicity at all. Finally, the probe was tested in an abdominal aortic aneurysm mouse model. Here, the probe enabled the differentiation between diseased animals and the sham group. By the increase of the Contrast-to-Noise Ratio (CNR), the diseases could be visualized. Additionally, an early prediction of the disease development, course, and mortality could be performed.

No description available.

The breast cancer susceptibility protein, BRCA1, is a tumor suppressor that helps maintain genomic integrity. Changes in BRCA1 that effect DNA repair processes can fuel cancer induction. The Kelly lab, at the Virginia Tech Carilion Research Institute, has recently developed a new methodology that employs silicon nitride (SiN) microchips to isolate BRCA1 assemblies from the nuclear material of breast cancer cells. These microchips are coated with adaptor proteins that include antibodies against target proteins of interest. The adaptor proteins are added in sequential steps to the coated microchips, followed by an aliquot of sample containing the protein of interest, such as BRCA1. The Kelly lab, partnered with Protochips Inc., developed these devices as a robust, tunable platform to monitor molecular processes, and refer to them as 'Cryo-SiN' in cryo-Electron Microscopy (EM) imaging. We are currently using Cryo-SiN to recruit BRCA1 protein assemblies to the microchip surface under mild conditions, while simultaneously preparing them for cryogenic preservation and EM imaging. This strategy presents a viable alternative to antibody affinity columns that require stringent elution steps to obtain protein complexes from the column. Another advantage of the microchip strategy is that it requires only a 30-minute nuclear extraction, a 60-minute enrichment procedure, and a 5-minute microchip capture step--a total of 95 minutes from initially lysing the cells to plunge-freezing the EM specimens. Therefore, these novel approaches represent a major departure from classical separation procedures that often require days to complete, during which time active protein assemblies can readily dissociate or become inactive. Overall, our use of BRCA1-specific microchips may reveal changes in the BRCA1 architecture during various stages of cancer progression--a major gap in knowledge that persists in cancer research. / M. S.