One of the largest problems in current medicine is the shortage of organs for transplant due to technological limitations in the storage of organs for any length of time. A possible solution to this problem would involve cryopreservation. However, current cryopreservatives such as sucrose or DMSO have concerning cytotoxic issues that limit their possible applications. A major cause of cryoinjury is the uncontrolled recrystallization of inter and intra-cellular ice crystals that occurs during the thawing process leading to mechanical damage and dehydration. The Ben lab has thus been interested in the design of compounds that are capable of inhibiting this process but do not possess other undesirable properties found in the native compounds. These synthetic analogues have been shown to increase cellular viability post-thaw. A series of mixed α/β glycopeptides are prepared and analyzed for antifreeze properties. The results of this study imply that it is not the gross conformation of the glycopeptide that is responsible for activity, but rather that intramolecular relationships may be responsible for disrupting the reorganization of ice. A technique was devised for the incorporation of triazoles into the analogues to investigate the importance of the linker and to greatly simplify the synthesis of a library of glycoconjugates. It was found that the IRI activity of glycopeptides is very sensitive to the distance between carbohydrate and peptide backbone. The electron density at the anomeric oxygen is an important parameter with respect to intramolecular networks. A series of substituted galactosides is presented that modify the electronics of the anomeric oxygen. The results demonstrate that decreasing electron density at this position appears to improve IRI activity in a predictable manner. To better understand the remarkable IRI activity of a key analogue, it was systematically truncated. This study led to the serendipitous discovery of a series of very highly IRI active analogues that do not contain a peptide backbone. These compounds represent the first non-glycopeptides that can show very significant IRI activity even at very low concentrations. The final portion of the thesis reports the efforts towards the preparation of a carbasugar analogue of AFGP-8.

DC-SIGN est une lectine tétramérique impliquée dans la réponse immunitaire adaptative; Elle reconnait à la fois les ligands mannosylés et fucosylés. Bien que les interactions protéine-saccharide soient essentielles à de multiples processus biologiques, les interactions individuelles sont faibles (de l'ordre du mM), ainsi, la multivalence du ligand est nécessaire.La première partie de ce projet est la construction d'un ligand polyfucosylé de DC-SIGN. Une structure multivalente dendrimérique est choisie pour son bon contrôle de la géométrie et de l'homogénité (macroscopique et microscopique).Dans une seconde partie, la stratégie de synthèse a été adaptée à différents monomères pour produire de multiples glycodendrimères. Ceux-ci pourront donner des renseignements sur la structure la plus adaptée aux interactions avec DC-SIGN. / DC-Sign is a tetrameric lectin presents on dendritic cells involved in the adaptive immune response; It recognizes both mannosylated and fucosylated ligands. Although protein-carbohydrate interactions are essential to many biological processes, individual interactions usually exhibit weak binding affinities (mM range), thus multivalency of the ligand is required. The first part of our project is the construction of a very active yet simple fucosylated synthetic ligands for DC-SIGN. As multivalent structure, dendrimers are chosen for their good control both in geometry and in homogeneity (macroscopic and microscopic). In a second part, the synthesis strategy was adapted to different monomers to produce various glycodendrimers. They could give us information on the more adapted structure for DC-SIGN interaction.

One of the largest problems in current medicine is the shortage of organs for transplant due to technological limitations in the storage of organs for any length of time. A possible solution to this problem would involve cryopreservation. However, current cryopreservatives such as sucrose or DMSO have concerning cytotoxic issues that limit their possible applications. A major cause of cryoinjury is the uncontrolled recrystallization of inter and intra-cellular ice crystals that occurs during the thawing process leading to mechanical damage and dehydration. The Ben lab has thus been interested in the design of compounds that are capable of inhibiting this process but do not possess other undesirable properties found in the native compounds. These synthetic analogues have been shown to increase cellular viability post-thaw. A series of mixed α/β glycopeptides are prepared and analyzed for antifreeze properties. The results of this study imply that it is not the gross conformation of the glycopeptide that is responsible for activity, but rather that intramolecular relationships may be responsible for disrupting the reorganization of ice. A technique was devised for the incorporation of triazoles into the analogues to investigate the importance of the linker and to greatly simplify the synthesis of a library of glycoconjugates. It was found that the IRI activity of glycopeptides is very sensitive to the distance between carbohydrate and peptide backbone. The electron density at the anomeric oxygen is an important parameter with respect to intramolecular networks. A series of substituted galactosides is presented that modify the electronics of the anomeric oxygen. The results demonstrate that decreasing electron density at this position appears to improve IRI activity in a predictable manner. To better understand the remarkable IRI activity of a key analogue, it was systematically truncated. This study led to the serendipitous discovery of a series of very highly IRI active analogues that do not contain a peptide backbone. These compounds represent the first non-glycopeptides that can show very significant IRI activity even at very low concentrations. The final portion of the thesis reports the efforts towards the preparation of a carbasugar analogue of AFGP-8.

No description available.

No description available.

De acordo com a Organização Mundial de Saúde (World Health Organization - WHO), aproximadamente 40 milhões de pessoas ao redor do mundo estão infectadas com HIV/AIDS. Atualmente, a epidemia tem sido controlada em grande parte do mundo ocidental, porém, projeções sugerem que, até o fim desta década, o número de incidência da doença poderá duplicar. Apesar das significantes melhoras na morbidade e mortalidade de pacientes infectados pelo HIV, o rápido surgimento de cepas resistentes aos agentes anti-HIV, além dos efeitos adversos e o alto custo de fármacos de última geração, torna-se necessário o continuo desenvolvimento de novas classes de agentes anti-HIV. A transcrição e multiplicação do RNA viral são dependentes das interações seqüência-específica entre duas proteínas reguladoras virais essenciais, Tat e Rev, com seus respectivos sítios no RNA, TAR e RRE. Durante a última década, os aminoglicosídeos foram introduzidos como ligantes universais do RNA, sendo capazes de se ligar ao TAR e ao RRE. A literatura apresenta diversos aminoglicosídeos que são capazes de se ligar ao TAR e inibir a interação Tat-TAR bem como, inibir competitivamente a ligação da proteína Rev ao RRE, como, por exemplo, a neomicina e tobramicina. Considerando a importância dos aminoglicosídeos e análogos nucleosídicos, conhecidamente eficazes na terapia antirretroviral, o trabalho foi direcionado para a síntese de conjugados de aminociclitol, 2- desoxi-estreptramina, e adenosina, bem como, dímeros de adenosina via estratégia de click chemistry por reação de cicloadição azido-alcino catalisada por Cu(I) (CuAAC). Para a síntese destes produtos, o precursor adenosina foi convertido no derivado 5\'-azido-5\'- desoxi-adenosina, o qual foi condensado com diversos diinos terminais comerciais, contendo diferentes grupos espaçantes, com a finalidade de explorar suas influências nas propriedades eletrônicas e estéricas nos conjugados de interesse frente à atividade anti-HIV. Os derivados alcinos presentes na posição C-5\' de adenosina, via grupo triazol, foram empregados para a síntese dos monômeros nucleosídeo-aminociclitóis, assim como, na síntese de dímeros nucleosíde0-aminociclitóis, via reação de cicloadição 1,3-dipolar, na presença de CuSO4, quantidade catalítica, e ascorbato de sódio, para geração in situ de Cu(I). Adicionalmente, alguns dos compostos, na concentração de 1mM, foram testados empregando o ensaio de ELISA para detecção da presença de proteína viral p24 em linhagem células H9 e avaliação de sua atividade antirretroviral. De acordo com o ensaio biológico, um dos compostos preparados apresentou, proporcionalmente ao crescimento da linhagem H9 (HIV) controle, atividade de inibição de formação da proteína viral p24 similar ao composto padrão zidovudina (AZT). Além disso, outros dois compostos também apresentaram um resultado relevante uma vez que suas atividades foram similares ao composto padrão lamivudina (3TC). Estes resultados sugerem que a presença de uma cadeia metilênica mais extensa, como cadeia lateral ou grupo espaçante, pode influenciar positivamente a atividade biológica por efeito hidrofóbico ou estérico. Por fim, os ensaios de viabilidade celular demonstraram que os compostos testados não foram citotóxicos nas condições testadas. / According to World Health Organization - WHO about 40 million of people are infected with HIV/AIDS. Currently, the epidemic has been controlled largely in the western world, since, projections suggest that, until this decade end, the disease incidence could increase. Despite significant improvements in morbidity and mortality of HIV-patients, quick emergence of resistant strains to anti-HIV agents, in addition to adverse effects and high cost of recent drugs, becomes necessary the ongoing development of new classes of HIV agents. Transcription and translation of the viral RNA are dependent of sequence-specific interactions among two essential viral regulatory proteins, Tat and Rev, and their corresponding TAR and RRE sites in HIV-1 RNA. Over the past decade, aminoglycosides were established as universal RNA linkers, being able to link to TAR and RRE. The literature reports several aminoglycosides that bind to TAR and inhibit Tat-TAR interaction, as well as, competitively inhibit the bind between Rev protein and RRE, such as: neomycin and tobramycin. Considering the importance of nucleosides analogs, effective in antiretroviral therapy, and aminoglycosides, the work was driven to the synthesis of aminocyclitol, 2- deoxy-streptamine, conjugated to the adenosine, as well as, conjugated dimers of adenosine by molecular duplication via click chemistry strategy involving copper-catalysed azide-alkyne cycloaddition reaction (CuAAC). For the synthesis of these products, the starting material adenosine was converted to 5\'-azide-5\'-deoxy-adenosine, which was conjugated with several commercials terminal dialkynes containing different intercalating groups in order to explore the influences of the steric and electronic properties of conjugates towards anti-HIV activity. Alkynes derivated at C-5\' position of adenosine, via triazole group, were used in the synthesis of nucleoside-linked aminocyclitols, as well as, nucleoside conjugated dimers by 1,3-dipolar cycloaddition reaction under microwave-assisted conditions (MW), using the catalytic system CuSO4/sodium ascorbate for the in situ generation of Cu(I). Additionally, several compounds, at concentration of 1mM, were tested in vitro by ELISA for detection of p24 protein in H9 cells to antiretroviral evaluation. According with the biologic assay, one of the compounds showed inhibition of p24 protein production similar to zidovudine (AZT), when compared to H9 cells line growth control, Furthermore, two compounds also showed important activities similar to lamivudine (3TC). These results suggest that the presence of a longer methylenic chain, as side chain or intercalating groups, could influence positively in the biologic activity due to hydrophobic or steric effects. Ultimately, the cell viability assays showed that compounds were not cytotoxic in the tested conditions.

De acordo com a Organização Mundial de Saúde (World Health Organization - WHO), aproximadamente 40 milhões de pessoas ao redor do mundo estão infectadas com HIV/AIDS. Atualmente, a epidemia tem sido controlada em grande parte do mundo ocidental, porém, projeções sugerem que, até o fim desta década, o número de incidência da doença poderá duplicar. Apesar das significantes melhoras na morbidade e mortalidade de pacientes infectados pelo HIV, o rápido surgimento de cepas resistentes aos agentes anti-HIV, além dos efeitos adversos e o alto custo de fármacos de última geração, torna-se necessário o continuo desenvolvimento de novas classes de agentes anti-HIV. A transcrição e multiplicação do RNA viral são dependentes das interações seqüência-específica entre duas proteínas reguladoras virais essenciais, Tat e Rev, com seus respectivos sítios no RNA, TAR e RRE. Durante a última década, os aminoglicosídeos foram introduzidos como ligantes universais do RNA, sendo capazes de se ligar ao TAR e ao RRE. A literatura apresenta diversos aminoglicosídeos que são capazes de se ligar ao TAR e inibir a interação Tat-TAR bem como, inibir competitivamente a ligação da proteína Rev ao RRE, como, por exemplo, a neomicina e tobramicina. Considerando a importância dos aminoglicosídeos e análogos nucleosídicos, conhecidamente eficazes na terapia antirretroviral, o trabalho foi direcionado para a síntese de conjugados de aminociclitol, 2- desoxi-estreptramina, e adenosina, bem como, dímeros de adenosina via estratégia de click chemistry por reação de cicloadição azido-alcino catalisada por Cu(I) (CuAAC). Para a síntese destes produtos, o precursor adenosina foi convertido no derivado 5\'-azido-5\'- desoxi-adenosina, o qual foi condensado com diversos diinos terminais comerciais, contendo diferentes grupos espaçantes, com a finalidade de explorar suas influências nas propriedades eletrônicas e estéricas nos conjugados de interesse frente à atividade anti-HIV. Os derivados alcinos presentes na posição C-5\' de adenosina, via grupo triazol, foram empregados para a síntese dos monômeros nucleosídeo-aminociclitóis, assim como, na síntese de dímeros nucleosíde0-aminociclitóis, via reação de cicloadição 1,3-dipolar, na presença de CuSO4, quantidade catalítica, e ascorbato de sódio, para geração in situ de Cu(I). Adicionalmente, alguns dos compostos, na concentração de 1mM, foram testados empregando o ensaio de ELISA para detecção da presença de proteína viral p24 em linhagem células H9 e avaliação de sua atividade antirretroviral. De acordo com o ensaio biológico, um dos compostos preparados apresentou, proporcionalmente ao crescimento da linhagem H9 (HIV) controle, atividade de inibição de formação da proteína viral p24 similar ao composto padrão zidovudina (AZT). Além disso, outros dois compostos também apresentaram um resultado relevante uma vez que suas atividades foram similares ao composto padrão lamivudina (3TC). Estes resultados sugerem que a presença de uma cadeia metilênica mais extensa, como cadeia lateral ou grupo espaçante, pode influenciar positivamente a atividade biológica por efeito hidrofóbico ou estérico. Por fim, os ensaios de viabilidade celular demonstraram que os compostos testados não foram citotóxicos nas condições testadas. / According to World Health Organization - WHO about 40 million of people are infected with HIV/AIDS. Currently, the epidemic has been controlled largely in the western world, since, projections suggest that, until this decade end, the disease incidence could increase. Despite significant improvements in morbidity and mortality of HIV-patients, quick emergence of resistant strains to anti-HIV agents, in addition to adverse effects and high cost of recent drugs, becomes necessary the ongoing development of new classes of HIV agents. Transcription and translation of the viral RNA are dependent of sequence-specific interactions among two essential viral regulatory proteins, Tat and Rev, and their corresponding TAR and RRE sites in HIV-1 RNA. Over the past decade, aminoglycosides were established as universal RNA linkers, being able to link to TAR and RRE. The literature reports several aminoglycosides that bind to TAR and inhibit Tat-TAR interaction, as well as, competitively inhibit the bind between Rev protein and RRE, such as: neomycin and tobramycin. Considering the importance of nucleosides analogs, effective in antiretroviral therapy, and aminoglycosides, the work was driven to the synthesis of aminocyclitol, 2- deoxy-streptamine, conjugated to the adenosine, as well as, conjugated dimers of adenosine by molecular duplication via click chemistry strategy involving copper-catalysed azide-alkyne cycloaddition reaction (CuAAC). For the synthesis of these products, the starting material adenosine was converted to 5\'-azide-5\'-deoxy-adenosine, which was conjugated with several commercials terminal dialkynes containing different intercalating groups in order to explore the influences of the steric and electronic properties of conjugates towards anti-HIV activity. Alkynes derivated at C-5\' position of adenosine, via triazole group, were used in the synthesis of nucleoside-linked aminocyclitols, as well as, nucleoside conjugated dimers by 1,3-dipolar cycloaddition reaction under microwave-assisted conditions (MW), using the catalytic system CuSO4/sodium ascorbate for the in situ generation of Cu(I). Additionally, several compounds, at concentration of 1mM, were tested in vitro by ELISA for detection of p24 protein in H9 cells to antiretroviral evaluation. According with the biologic assay, one of the compounds showed inhibition of p24 protein production similar to zidovudine (AZT), when compared to H9 cells line growth control, Furthermore, two compounds also showed important activities similar to lamivudine (3TC). These results suggest that the presence of a longer methylenic chain, as side chain or intercalating groups, could influence positively in the biologic activity due to hydrophobic or steric effects. Ultimately, the cell viability assays showed that compounds were not cytotoxic in the tested conditions.

Ce travail s’inscrit dans le domaine des cages moléculaires, édifices dont la géométrie définit unecavité tridimensionnelle capable de contenir d’autres entités.L’objectif de cette thèse est la synthèse de cages moléculaires covalentes possédant despropriétés d’encapsulation et une taille modulables. Les cages synthétisées avec succèsincorporent des porphyrines de zinc ou bases libres, ainsi que huit ligands triazoles périphériques.Des molécules ont pu être encapsulées par coordination aux porphyrines ou par interactions π, cequi démontre la capacité de la cage à s’adapter à l’invité grâce à sa flexibilité. La coordinationd’ions argent(I) permet de passer d’une conformation aplatie à une conformation ouverte. Lecaractère commutable de la cage a été démontré par décoordination de ces ions. Enfin, lacoordination d’ions argent(I) aux ligands de la cage augmente la stabilité de deux ligandsditopiques, le DABCO et la pipérazine, au sein de la cavité. Elle permet aussi l’accès de la cavité àdes molécules non encapsulées en l’absence d’argent(I). Ces résultats démontrent le contrôleallostérique de l’encapsulation de molécules par un stimulus chimique. / This work belongs to the field of molecular cages, hollow structures enclosing a three-dimensionalcavity able to encapsulate other molecules.The goal of this thesis include the synthesis of molecular covalent cages with a controllablecavity size able to perform switchable guest encapsulation. A DABCO-templated click reactionafforded three flexible covalent cages, endowed with two zinc(II) or free-base porphyrins and eightperipheral triazole ligands. Various guest molecules could be encapsulated by coordination toporphyrins or π-π interactions, in an induced-fit mechanism, probing the ability of the cage to adaptto the guest thanks to its flexibility. Coordination of silver(I) ions to the peripheral triazoles allow toswitch from a flattened to an open and locked conformation. Removal of the ions proved thecommutability of the cage. Finally, coordination of silver(I) ions to triazole ligands increase thestability of two ditopic ligands, DABCO and piperazine, inside the cavity. It also allowed the accessto the cavity of molecules that were not otherwise encapsulated. These results shows the allostericcontrol of guest encapsulation by a chemical stimulus.

No description available.

Ce travail de thèse a consisté en la conception et la réalisation d’une nano-sonde hybride luminescente visant à permettre la détection précoce du cancer de la prostate. La première partie de ce projet a été consacré à la synthèse, par une voie de chimie click, d’une bibliothèque d’acides 4-triazolyl dipicoliniques substitués en position 4 du triazole par une large gamme de substituants. Ces diacides ont permis d’obtenir les complexes d’europium(III) et de terbium(III) correspondant, qui ont montré d’excellentes propriétés optiques, avec des rendements quantiques de luminescence sous excitation UV pouvant atteindre 60% et 36%, pour les complexes d’europium(III) et deterbium(III) respectivement. D’autre-part, ces fluorophores ont pu être excités efficacement en régime biphotonique, à la fois au travers des transitions S0 ®S1 et S0 ®T1. Sur la base de ces résultats, certains de ces chélates ont été sélectionnés afin de les incorporer dans des nanoparticules de silice. Le procédé d’élaboration par microémulsion inverse s’est révélé efficace pour l’incorporation des complexes électriquement neutres, mais n’a pas permis celle de nanohybrides incorporant des complexes chargés négativement. Ces nanohybrides présentent des propriétés optiques caractéristiques des lanthanides, avec des rendements quantiques allant jusqu’à 30%. La surface de ces nano-objets a ensuite été fonctionnalisée par des groupements amino, qui ont permis le greffage de bras espaceur et d’un vecteur ciblant la PSMA, l’un des signaux du cancer de la prostate, nous donnant ainsi accès à un modèle de nano-sonde luminescente. Un autre volet de ce travail a été dédié à l’étude de nouveaux analogues du NAAG, substrat naturel de la PSMA. Bien que la synthèse des deux composés cibles, sélectionnés parmi une vingtaine de structures par modélisation moléculaire, n’ait pu aboutir, elle a été largement avancée. Enfin, la dernière partie de ce travail décrit les premiers résultats obtenus in vitro et in vivo avec les nanosondes. Ces études ont porté sur l’évaluation de la cytotoxicité des nanoparticules ainsi que sur leur biodistribution chez la souris saine et chez la souris porteuse d’une tumeur prostatique. Cette étude a révélé une élimination rapide des nanoparticules par l’organisme, mais n’a malheureusement pas pu mettre en évidence un marquage des zones tumorales par les nanosondes. / The aim of this project was the design of a luminescent nanoprobe allowing the early prostate cancer detection.The first part of this project was the synthesis, through a click chemistry approach, of a library of 4-triazolyl dipicolinic acid substituted in position 4 of the triazole by a wide range of substitutive groups. These diacids were used to synthesise the corresponding europium(III) and terbium(III) complexes, which showed excellent optical properties, with photoluminescence quantum yield under UV excitation reaching 60% for europium(III) complexes and 36% for terbium(III) complexes. Moreover, these phosphores have been efficiently excited in biphotonic regime through the transitions S0 ®S1 and S0 ®T1. The more interesting chelates were selected for their further embedding into silica nanoparticles. The water-in-oil emulsion process showed a great efficiency for the incorporation of electrically neutral complexes, but did not allow the embedding of negatively charged ones. The resulting nanohybrids showed optical properties typical of lanthanides, presenting photoluminescence quantum yields up to 30%. The nanoparticles surface was then functionalised by amino groups, which were used to graft a spacer then a prostate tumour cells vector, giving us a luminescent nanoprobe model. The third section of this work was devoted to the study of new analogues of NAAG, the natural substrate of the PSMA, one of the prostatic cancer signals. Although the synthesis of the two target compounds, selected from more than 20 structures by molecular modelling, was uncompleted, they are now within easy reach. The last part describes the preliminary results obtained in vitro and in vivo with the nanoprobes. These studies were focused on the nanoparticles cytotoxitcity assessment, depending on the surface functionalisation, and on their distribution, in healthy and in prostatic tumour bearing mice. This study revealed the fast elimination of the nanoparticles by the organism, but did not show any concentration of nanoprobes in tumoral area.