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O fator CIITA é a proteína responsável por controlar a transcrição de genes do complexo principal de histocompatibilidade de classe II (MHC II) envolvidos na apresentação antigênica a linfócitos T CD4+. A expressão desta proteína é complexa e célula-específica, dependendo de mecanismos de regulação transcricionais e póstranscricionais. Com o intuito de investigar o potencial do fator CIITA como adjuvante molecular, no presente estudo desenvolvemos e validamos sistemas de transferência gênica capazes de promover a eficiente expressão de CIITA em vários tipos celulares. Além disso, investigamos a regulação pós-traducional deste fator em células não hematopoéticas. Desta forma, foram produzidos um vetor plasmidial e um vetor lentiviral, ambos carreando a sequência do fator CIITA humano desenhada in silico visando a eliminação de elementos cis-reguladores, e otimizada para eficiente expressão em células humanas. A transfecção/transdução de três linhagens de células humanas não hematopoéticas resultou na eficiente expressão de CIITA com localização nuclear apropriada. Células expressando CIITA apresentaram síntese de novo do MHC II, confirmando a funcionalidade da proteína e validando ambos os vetores para a análise futura da atividade adjuvante do CIITA em imunizações gênicas. Ensaios preliminares de inoculação de explantes de pele humana com o vetor lentiviral evidenciaram a eficiente transdução e expressão do CIITA exógeno em células primárias. Em seguida, células dendríticas (DCs) derivadas de monócitos de indivíduos saudáveis ou infectados com HIV-1 foram transduzidas com o vetor lentiviral para confirmar a expressão do CIITA em células primárias e avaliar a aplicação desse sistema adjuvante no aprimoramento da vacina de DCs anti-HIV. DCs de indivíduos saudáveis ou infectados foram transduzidas com sucesso pelo lentivírus, o qual induziu uma produção prolongada do mRNA codificando CIITA. Entretanto, os vetores lentivirais induziram um aumento inespecífico da expressão de marcadores fenotípicos das DCs, incluindo as moléculas do MHC II, o que impediu a avaliação indireta da expressão e atividade do fator CIITA através da detecção da expressão aumentada do MHC II. Ensaios futuros irão avaliar se o fator transcricional é expresso pelas DCs transduzidas ou se essas células apresentam um controle mais restrito da expressão do CIITA comparadas às linhagens celulares avaliadas. Interessantemente, ensaios de western blot comparativos entre as três linhagens de células humanas transfectadas/transduzidas, juntamente com ensaios de inibição da degradação protéica pelo inibidor do proteassoma, nos permitiu descrever um novo mecanismo de regulação pós-traducional do CIITA. Aqui, nós identificamos que cada tipo de célula não hematopoética mantém níveis específicos da proteína, e portanto, da sua atividade transcricional, através da regulação da degradação do CIITA pelo proteassoma. Essa regulação é mediada pela modulação dos níveis das proteínas da leucemia promielocítica (PML) acopladas a proteínas SUMO (modificadores pequenos similares à ubiquitina), modificação pós-traducional requerida para a interação PML-CIITA que impede a degradação pelo proteassoma. Esse novo mecanismo aqui descrito contribui para o entendimento ainda incipiente da regulação pós-traducional do fator CIITA em células não hematopoéticas e pode ter implicações importantes na aplicação dessa proteína como adjuvante molecular para imunoterapias / The CIITA factor is a protein responsible for controlling the transcription of major histocompatibility complex class II (MHC II) genes involved on antigen presentation to CD4+ T helper cells. The expression of this transcription factor is complex and differs in various cell types depending on transcriptional and post-transcriptional regulatory mechanisms. In order to investigate the CIITA factor potential as molecular adjuvant, here we developed and validated two gene delivery systems capable of promoting efficient CIITA expression in various human cell types. Additionally, we applied the delivery systems to investigate the post-translational regulation of this factor in nonimmune cells. A DNA plasmid and a lentiviral vector were produced, both carrying the human CIITA DNA sequence in silico designed to avoid cis-regulatory elements, and genetic optimized for expression efficacy in human cells. Transfection or transduction of three different non-immune human cell lines resulted in efficient CIITA expression with proper nuclear localization. The CIITA-expressing cells presented de novo MHC II molecules expression confirming the functionality of the exogenous protein, and validating both delivery systems for the future analysis of the CIITA adjuvant activity in genetic immunizations. Preliminary assays involving the inoculation of the lentiviral vector into human skin explants showed efficient transduction and expression of exogenous CIITA in primary cells. Next, monocyte-derived dendritic cells (DCs) from healthy individuals and HIV-1-infected patients were transduced with the lentiviral vector to confirm the exogenous CIITA expression in primary human cells and also evaluate the applicability of this adjuvant system to improve the DC-based vaccines against HIV. DCs from healthy and infected individuals were successfully transduced by the lentivirus, which induced a sustained CIITA mRNA production. However, the vector particles by themselves induced an unspecific upregulation of DC`s phenotypic surface markers, including the MHC II molecules, impairing our strategy to indirectly evaluate CIITA expression and activity through the detection of MHC II enhanced expression. Further investigations are necessary to confirm whether the transcription factor is efficiently expressed in transduced DCs or if these cells present a more restrict control of CIITA protein expression than the evaluated non-immune cells. Interestingly, western blot assays comparing the three human cell lines, transfected or transduced, along with inhibition of protein degradation by proteasome inhibitor treatments, allowed us to describe a new and intricate mechanism of CIITA post-translational regulation. Here we identified that each non-immune cell type maintain specific protein levels, and hence transcriptional activity, by modulating the rate of CIITA proteasomal degradation. This modulation is achieved by controlling the levels of Promyelocytic Leukemia (PML) proteins attached to Small Ubiquitin-like Modifier (SUMO) proteins, a post-translational modification required for the PML-CIITA interaction, which impairs the proteasomal degradation. This new mechanism described here contributes to the developing understanding of the CIITA post-translational regulation in non-immune cells, and might have important implications in the use of this transcription factor as a molecular adjuvant for immunotherapies

Le but de ce travail de thèse consiste à étudier les propriétés physico-chimiques des verres chalcogénures afin de pouvoir les utiliser comme membranes de capteurs chimiques destinés pour le dosage des ions Hg²⁺. Dans un premier temps, les propriétés macroscopiques des systèmes vitreux AgY-As₂S₃ (Y = Br, I), HgS-GeS₂, AgI-HgS-As₂S₃ et AgI-HgS-GeS₂, telles que les densités et les températures caractéristiques (Tg et Tc) ont été mesurées et analysées selon les compositions des verres. Puis, dans un second temps, les propriétés de transport ont été étudiés à l'aide de la spectroscopie d'impédance complexe d'une part, ou d'autre part, par des mesures de la résistivité. Ces dernières montrent que les verres de chalcogénures dopés à l'halogénure d'argent présentent deux différents régimes de transports au-dessus du seuil de percolation xc ≈ 30 ppm : (i) domaine de percolation critique, et (ii) domaine contrôlé par modificateur. Vient ensuite la troisième partie, elle consiste à déchiffrer les relations composition/structure/propriété grâce à plusieurs études structurales. Des mesures par spectroscopie Raman, par diffraction de neutrons et de rayons X haute énergie, par diffusion des neutrons sous petits angles (SANS), ainsi que des modélisations RMC/DFT et AMID ont été réalisées. Enfin, la dernière partie de ce travail était une étude préliminaire des caractéristiques des nouveaux capteurs chimiques. Il a été consacré à l'étude des relations entre la composition et la sensibilité des membranes ainsi qu'aux limites de détection qui les définissent. / The aim of the thesis is to study the physicochemical properties of the silver halide doped chalcogenide glasses for the possibility to use them as chemical sensors for quantitative analysis of Hg²⁺ ions. First, the macroscopic properties of AgY-As₂S₃ (Y = Br, I), HgS-GeS₂, AgI-HgS-As₂S₃ and AgI-HgS-GeS₂ glassy systems such as the densities and the characteristic temperatures (Tg and Tc) were measured and analyzed according to the glass compositions. Second, the transport properties were studied using complex impedance and dc conductivity. Measurements show that the silver halide doped chalcogenide glasses exhibit two drastically different ion transport regimes above the percolation threshold at xc ≈ 30 ppm : (i) critical percolation, and (ii) modifier-controlled regimes. Third, to unveil the composition/structure/property relationships, various structural studies were carried out. Raman spectroscopy, high-energy X-ray diffraction, neutron diffraction and small-angle neutron scattering experiments, together with RMC/DFT and AMID modelling were employed. Finally, the last part was a preliminary study of the characteristics of new chemical sensors. It was devoted to study the relationship between the membranes' composition and sensitivity but also detection limits.

O fator CIITA é a proteína responsável por controlar a transcrição de genes do complexo principal de histocompatibilidade de classe II (MHC II) envolvidos na apresentação antigênica a linfócitos T CD4+. A expressão desta proteína é complexa e célula-específica, dependendo de mecanismos de regulação transcricionais e póstranscricionais. Com o intuito de investigar o potencial do fator CIITA como adjuvante molecular, no presente estudo desenvolvemos e validamos sistemas de transferência gênica capazes de promover a eficiente expressão de CIITA em vários tipos celulares. Além disso, investigamos a regulação pós-traducional deste fator em células não hematopoéticas. Desta forma, foram produzidos um vetor plasmidial e um vetor lentiviral, ambos carreando a sequência do fator CIITA humano desenhada in silico visando a eliminação de elementos cis-reguladores, e otimizada para eficiente expressão em células humanas. A transfecção/transdução de três linhagens de células humanas não hematopoéticas resultou na eficiente expressão de CIITA com localização nuclear apropriada. Células expressando CIITA apresentaram síntese de novo do MHC II, confirmando a funcionalidade da proteína e validando ambos os vetores para a análise futura da atividade adjuvante do CIITA em imunizações gênicas. Ensaios preliminares de inoculação de explantes de pele humana com o vetor lentiviral evidenciaram a eficiente transdução e expressão do CIITA exógeno em células primárias. Em seguida, células dendríticas (DCs) derivadas de monócitos de indivíduos saudáveis ou infectados com HIV-1 foram transduzidas com o vetor lentiviral para confirmar a expressão do CIITA em células primárias e avaliar a aplicação desse sistema adjuvante no aprimoramento da vacina de DCs anti-HIV. DCs de indivíduos saudáveis ou infectados foram transduzidas com sucesso pelo lentivírus, o qual induziu uma produção prolongada do mRNA codificando CIITA. Entretanto, os vetores lentivirais induziram um aumento inespecífico da expressão de marcadores fenotípicos das DCs, incluindo as moléculas do MHC II, o que impediu a avaliação indireta da expressão e atividade do fator CIITA através da detecção da expressão aumentada do MHC II. Ensaios futuros irão avaliar se o fator transcricional é expresso pelas DCs transduzidas ou se essas células apresentam um controle mais restrito da expressão do CIITA comparadas às linhagens celulares avaliadas. Interessantemente, ensaios de western blot comparativos entre as três linhagens de células humanas transfectadas/transduzidas, juntamente com ensaios de inibição da degradação protéica pelo inibidor do proteassoma, nos permitiu descrever um novo mecanismo de regulação pós-traducional do CIITA. Aqui, nós identificamos que cada tipo de célula não hematopoética mantém níveis específicos da proteína, e portanto, da sua atividade transcricional, através da regulação da degradação do CIITA pelo proteassoma. Essa regulação é mediada pela modulação dos níveis das proteínas da leucemia promielocítica (PML) acopladas a proteínas SUMO (modificadores pequenos similares à ubiquitina), modificação pós-traducional requerida para a interação PML-CIITA que impede a degradação pelo proteassoma. Esse novo mecanismo aqui descrito contribui para o entendimento ainda incipiente da regulação pós-traducional do fator CIITA em células não hematopoéticas e pode ter implicações importantes na aplicação dessa proteína como adjuvante molecular para imunoterapias / The CIITA factor is a protein responsible for controlling the transcription of major histocompatibility complex class II (MHC II) genes involved on antigen presentation to CD4+ T helper cells. The expression of this transcription factor is complex and differs in various cell types depending on transcriptional and post-transcriptional regulatory mechanisms. In order to investigate the CIITA factor potential as molecular adjuvant, here we developed and validated two gene delivery systems capable of promoting efficient CIITA expression in various human cell types. Additionally, we applied the delivery systems to investigate the post-translational regulation of this factor in nonimmune cells. A DNA plasmid and a lentiviral vector were produced, both carrying the human CIITA DNA sequence in silico designed to avoid cis-regulatory elements, and genetic optimized for expression efficacy in human cells. Transfection or transduction of three different non-immune human cell lines resulted in efficient CIITA expression with proper nuclear localization. The CIITA-expressing cells presented de novo MHC II molecules expression confirming the functionality of the exogenous protein, and validating both delivery systems for the future analysis of the CIITA adjuvant activity in genetic immunizations. Preliminary assays involving the inoculation of the lentiviral vector into human skin explants showed efficient transduction and expression of exogenous CIITA in primary cells. Next, monocyte-derived dendritic cells (DCs) from healthy individuals and HIV-1-infected patients were transduced with the lentiviral vector to confirm the exogenous CIITA expression in primary human cells and also evaluate the applicability of this adjuvant system to improve the DC-based vaccines against HIV. DCs from healthy and infected individuals were successfully transduced by the lentivirus, which induced a sustained CIITA mRNA production. However, the vector particles by themselves induced an unspecific upregulation of DC`s phenotypic surface markers, including the MHC II molecules, impairing our strategy to indirectly evaluate CIITA expression and activity through the detection of MHC II enhanced expression. Further investigations are necessary to confirm whether the transcription factor is efficiently expressed in transduced DCs or if these cells present a more restrict control of CIITA protein expression than the evaluated non-immune cells. Interestingly, western blot assays comparing the three human cell lines, transfected or transduced, along with inhibition of protein degradation by proteasome inhibitor treatments, allowed us to describe a new and intricate mechanism of CIITA post-translational regulation. Here we identified that each non-immune cell type maintain specific protein levels, and hence transcriptional activity, by modulating the rate of CIITA proteasomal degradation. This modulation is achieved by controlling the levels of Promyelocytic Leukemia (PML) proteins attached to Small Ubiquitin-like Modifier (SUMO) proteins, a post-translational modification required for the PML-CIITA interaction, which impairs the proteasomal degradation. This new mechanism described here contributes to the developing understanding of the CIITA post-translational regulation in non-immune cells, and might have important implications in the use of this transcription factor as a molecular adjuvant for immunotherapies

Chan, Ho Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 263-283). / Abstracts in English and Chinese. / Examination Committee List --- p.i / Acknowledgements --- p.ii / Abstract --- p.iv / 摘要 --- p.vi / Table of Contents --- p.viii / List of Abbreviations --- p.xvii / List of Figures --- p.xx / List of Tables --- p.xxv / Chapter Chapter I --- Introduction --- p.1 / Chapter 1.1 --- SUMO (Small Ubiquitin-like Modifier) and SUMOylation --- p.1 / Chapter 1.1.1 --- "Ubiquitin, Ubiquitin-like proteins and SUMO isoforms" --- p.2 / Chapter 1.1.2 --- SUMO cycle --- p.5 / Chapter 1.1.2.1 --- SUMO conjugation consensus sequence --- p.5 / Chapter 1.1.2.2 --- SUMO maturation --- p.6 / Chapter 1.1.2.3 --- SUMO conjugation cascade --- p.7 / Chapter 1.1.2.4 --- SUMO deconjugation --- p.9 / Chapter 1.1.3 --- Mode of SUMO action --- p.12 / Chapter 1.1.4 --- Biological functions of SUMO --- p.13 / Chapter 1.1.4.1 --- SUMO in cancer --- p.14 / Chapter 1.2 --- Human cervical cancer and human papillomavirus (HPV) --- p.17 / Chapter 1.2.1 --- Infectious cycle of HPV-16 --- p.18 / Chapter 1.2.1.1 --- Viral entry --- p.18 / Chapter 1.2.1.2 --- Maintenance --- p.18 / Chapter 1.2.1.3 --- Deregulation of cell cycle --- p.19 / Chapter 1.2.1.4 --- Amplification and virion release --- p.20 / Chapter 1.2.2 --- Viral cancer induction --- p.22 / Chapter 1.2.2.1 --- Integration into the host genome --- p.22 / Chapter 1.2.2.2 --- Viral oncoproteins E6 and E7 --- p.23 / Chapter 1.2.3 --- SUMOylation and HPV --- p.24 / Chapter 1.2.3.1 --- Known examples of virus-host SUMOylation system interaction --- p.24 / Chapter 1.2.3.2 --- Other possible mode of virus-SUMO interaction --- p.26 / Chapter 1.3 --- A novel labeling method: biarsenical-tetracysteine labeling in SUMO study --- p.28 / Chapter 1.3.1 --- Potential use of 2As-4Cys system in SUMO studies --- p.31 / Chapter 1.3.2 --- Potential use of 2As-4Cys system in SUMO proteomics --- p.31 / Chapter 1.4 --- Objectives of the present study --- p.34 / Chapter Chapter II --- Proteomics investigation of SUMOylation in human cervical carcinoma cell line HeLa --- p.35 / INTRODUCTION --- p.35 / Chapter 2.1 --- MATERIALS --- p.37 / Chapter 2.1.1 --- Vectors for expression of SUMO and SUMOylation enzymes in E. coli --- p.37 / Chapter 2.1.2 --- E.coli cell strains --- p.38 / Chapter 2.1.3 --- Mammalian cell lines --- p.39 / Chapter 2.1.4 --- E.coli growth mediums --- p.40 / Chapter 2.1.5 --- Mammalian cell growth medium --- p.41 / Chapter 2.1.6 --- Reagents and buffers --- p.41 / Chapter 2.1.6.1 --- Reagents and buffers for molecular cloning --- p.41 / Chapter 2.1.6.2 --- Reagents and buffers for E.coli protein expression --- p.43 / Chapter 2.1.6.3 --- Reagents and buffers for mammalian cell culture --- p.44 / Chapter 2.1.6.4 --- Reagents and buffers for Western blot study --- p.45 / Chapter 2.1.7 --- Reagents and solutions for two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) sample preparation --- p.46 / Chapter 2.1.7.1 --- Reagents and solutions for 2-DE --- p.46 / Chapter i. --- 2-DE sample preparation --- p.46 / Chapter ii. --- First dimensional gel electrophoresis -isoelectric focusing (IEF) --- p.46 / Chapter iii. --- Second dimensional gel electrophoresis -SDS-PAGE --- p.47 / Chapter iv. --- Silver staining --- p.47 / Chapter 2.1.7.2 --- Reagents and solutions for mass spectrometry sample preparation --- p.48 / Chapter i. --- Destaining of silver stained gel spots --- p.48 / Chapter ii. --- Trypsin digestion --- p.48 / Chapter iii. --- Peptide extraction --- p.48 / Chapter iv. --- Desalting and concentration of peptide mixture --- p.49 / Chapter 2.2 --- METHODS --- p.50 / Chapter 2.2.1 --- Molecular cloning of SUMO-1 into pET-28m and pHM6 vectors --- p.50 / Chapter 2.2.1.1 --- Design of primers for the cloning of SUMO-1 --- p.50 / Chapter 2.2.1.2 --- DNA amplification by polymerase chain reaction (PCR) --- p.51 / Chapter 2.2.1.3 --- DNA extraction from agarose gels --- p.52 / Chapter 2.2.1.4 --- Restriction digestion of vectors and purified PCR products --- p.54 / Chapter 2.2.1.5 --- Ligation of SUMO cDNA into expression vector pET-28m and pHM6 --- p.55 / Chapter 2.2.1.6 --- Preparation of competent cells --- p.56 / Chapter 2.2.1.7 --- Transformation of ligated mixture into competent DH5a --- p.56 / Chapter 2.2.1.8 --- Preparation of plasmid DNA --- p.57 / Chapter 2.2.1.8.1 --- Mini-preparation of plasmid DNA --- p.57 / Chapter 2.2.1.8.2 --- Midi-preparation of plasmid DNA --- p.58 / Chapter 2.2.1.8.3 --- DNA quantification and quality measurement --- p.60 / Chapter 2.2.2 --- "Expression of His6-tagged SUMO, ubc9, TDG, GST-tagged El and MBP-tagged Prdx 1 with E.coli" --- p.60 / Chapter 2.2.3 --- "Purification of His6-tagged SUMO, ubc9, TDG, GST-tagged El and MBP-tagged Prdx 1" --- p.62 / Chapter 2.2.3.1 --- Affinity chromatography --- p.65 / Chapter 2.2.3.1.1 --- Ni-NTA affinity chromatography --- p.65 / Chapter 2.2.3.1.2 --- Heparin affinity chromatography --- p.66 / Chapter 2.2.3.1.3 --- Glutathione affinity chromatography --- p.66 / Chapter 2.2.3.1.4 --- Amylose affinity chromatography --- p.67 / Chapter 2.2.3.2 --- Ion exchange chromatography --- p.68 / Chapter 2.2.3.2.1 --- Anion exchange chromatography --- p.68 / Chapter 2.2.3.2.2 --- Cation exchange chromatography --- p.68 / Chapter 2.2.3.3 --- Size exclusion chromatography --- p.69 / Chapter 2.2.3.4 --- Purification strategies --- p.70 / Chapter 2.2.3.4.1 --- Purification of His6-tagged SUMO --- p.70 / Chapter 2.2.3.4.2 --- Purification of His6-tagged TDG --- p.71 / Chapter 2.2.3.4.3 --- Purification of His6-tagged ubc9 --- p.72 / Chapter 2.2.3.4.4 --- Purification of GST-tagged El --- p.73 / Chapter 2.2.3.4.5 --- Purification of MBP-tagged Prdx 1 --- p.74 / Chapter 2.2.4 --- HeLa and C-33A cell culturing and protein extraction --- p.75 / Chapter 2.2.4.1 --- HeLa and C-33A cell culturing --- p.75 / Chapter 2.2.4.2 --- Protein extraction for in vitro SUMOylation assay --- p.76 / Chapter 2.2.5 --- Protein quantification with Bradford assay --- p.76 / Chapter 2.2.6 --- In vitro SUMO conjugation assay --- p.77 / Chapter 2.2.6.1 --- In vitro SUMO conjugation system optimization --- p.77 / Chapter 2.2.6.2 --- In vitro SUMO conjugation of HeLa cell extract --- p.78 / Chapter 2.2.7 --- Transient transfection of pHM6-SUMO-l into HeLa cells and protein extraction from HeLa cells --- p.79 / Chapter 2.2.7.1 --- Transfection with lipofection method --- p.79 / Chapter 2.2.7.2 --- Determination of transfection efficiency --- p.80 / Chapter 2.2.7.3 --- Whole cell protein extraction of transfected cells --- p.81 / Chapter 2.2.8 --- Protein quantification with BCA assay --- p.81 / Chapter 2.2.9 --- SDS-polyacrylamide gel electrophoresis (SDS-PAGE) --- p.83 / Chapter 2.2.10 --- Western blot analysis --- p.84 / Chapter 2.2.10.1 --- Electro-transfer blotting --- p.84 / Chapter 2.2.10.2 --- Immunoblotting with antibodies --- p.84 / Chapter 2.2.10.3 --- ECL detection --- p.85 / Chapter 2.2.10.4 --- Mild stripping for re-probing --- p.86 / Chapter 2.2.11 --- Two-dimensional gel electrophoresis (2-DE) --- p.86 / Chapter 2.2.11.1 --- Sample preparation --- p.86 / Chapter 2.2.11.2 --- First dimension gel electrophoresis -isoelectric focusing (IEF) --- p.87 / Chapter 2.2.11.3 --- Second dimension gel electrophoresis -SDS-PAGE --- p.88 / Chapter 2.2.11.3.1 --- Strip equilibration --- p.88 / Chapter 2.2.11.3.2 --- 16 x 18cm SDS-PAGE --- p.88 / Chapter 2.2.11.4 --- Visualization of proteins on SDS-polyacrylamide gel --- p.90 / Chapter 2.2.11.4.1 --- Silver staining --- p.90 / Chapter 2.2.11.4.2 --- Coomassie Blue® R250 staining --- p.91 / Chapter 2.2.12 --- Sample preparation for mass spectrometry analysis --- p.92 / Chapter 2.2.12.1 --- Destaining and trypsin digestion --- p.92 / Chapter 2.2.12.2 --- Extraction of peptide mixture --- p.93 / Chapter 2.2.12.3 --- Desalting and concentration of peptide mixture --- p.93 / Chapter 2.3 --- RESULTS --- p.95 / Chapter 2.3.1 --- Construction of recombinant pET-28m-SUMO-l and pHM6-SUMO-l --- p.95 / Chapter 2.3.2 --- "Purification of His6-tagged SUMO, ubc9, TDG and GST-tagged El" --- p.98 / Chapter 2.3.2.1 --- Purification of His6-SUMO --- p.98 / Chapter 2.3.2.2 --- Purification of His6-TDG --- p.101 / Chapter 2.3.2.3 --- Purification of His6-ubc9 --- p.104 / Chapter 2.3.2.4 --- Purification of GST-El --- p.106 / Chapter 2.3.3 --- In vitro SUMO conjugation assay --- p.108 / Chapter 2.3.3.1 --- Optimization of in vitro SUMO conjugation system --- p.108 / Chapter 2.3.3.2 --- In vitro SUMO conjugation of HeLa cell protein extract --- p.111 / Chapter 2.3.3.2.1 --- Protein extraction for in vitro sumoylation assay --- p.111 / Chapter 2.3.3.2.2 --- In vitro SUMOylation of HeLa cell lysate --- p.114 / Chapter 2.3.4 --- Differential proteomes of control and in vitro SUMOylated HeLa total cellular extract --- p.116 / Chapter 2.3.4.1 --- Mass spectrometric identification of differential protein candidates --- p.123 / Chapter 2.3.5 --- Overexpression of SUMO-1 in HeLa cells by transient transfection --- p.127 / Chapter 2.3.6 --- Differential proteomes of total cellular protein extract from control and SUMO-1 transfected HeLa cells --- p.128 / Chapter 2.3.6.1 --- Mass spectrometric identification of differential protein candidates --- p.132 / Chapter 2.4 --- Proteins identified in proteomic study with in vitro SUMOylation -Analysis of protein candidate --- p.133 / Chapter 2.4.1 --- Proteins identified from the in vitro investigation --- p.133 / Chapter 2.4.2 --- Verification of putative SUMO substrate Prdx 1 --- p.139 / Chapter 2.4.2.1 --- Purification of Prdx 1 --- p.139 / Chapter 2.4.2.2 --- In vitro SUMOylation of Prdx 1 --- p.142 / Chapter 2.4.3 --- Highlights of the proteins identified --- p.145 / Chapter 2.4.3.1 --- DJ-1 protein --- p.145 / Chapter 2.4.3.2 --- nm23A --- p.145 / Chapter 2.4.3.3 --- v-crk protein of CT10 --- p.146 / Chapter 2.4.3.4 --- Annexin I --- p.146 / Chapter 2.4.3.5 --- "Enolase 1, aldolase A, triosephosphate isomerase (TIM) and phosphoglycerate mutase 1" --- p.147 / Chapter 2.4.3.6 --- CyclophilinA(CypA) --- p.148 / Chapter 2.4.3.7 --- Stress induced phosphoprotein 1 (Stip 1) --- p.148 / Chapter 2.4.3.8 --- TSA and peroxiredoxin 1 (Prdx 1) --- p.149 / Chapter 2.5 --- Proteins identified in proteomic study with overexpression of SUMO-1 in HeLa cells -Analysis of protein candidate --- p.150 / Chapter 2.5.1 --- Proteins identified from the in vivo investigation --- p.150 / Chapter 2.5.2 --- Verification of upregulation of keratin 17 --- p.157 / Chapter 2.5.2.1 --- Immunoblotting against keratin 17 --- p.157 / Chapter 2.5.3 --- Highlights of the proteins identified --- p.159 / Chapter 2.5.3.1 --- "Heat shock proteins (Hsp 60, 70 and 27)" --- p.159 / Chapter 2.5.3.2 --- 14-3-3σ protein (SFN protein) --- p.161 / Chapter 2.5.3.3 --- PDZ-RGS3 --- p.162 / Chapter 2.5.3.4 --- "Keratins 8, 17" --- p.163 / Chapter 2.5.3.5 --- XIAP-1 --- p.164 / Chapter 2.5.3.6 --- ISG15 --- p.164 / Chapter 2.6 --- DISCUSSION --- p.166 / Chapter Chapter III --- Characterization of a novel fluorescent labeling method: Biarsencial-tetracysteine labeling in SUMO study --- p.182 / INTRODUCTION --- p.182 / Chapter 3.1 --- MATERIALS --- p.184 / Chapter 3.1.1 --- "Molecular cloning, protein expression and purification of pET-28m-4Cys 1 -SUMO-1 and pET-28m-4Cys2-SUMO-1" --- p.184 / Chapter 3.1.2 --- Mammalian cell culture and transient transfection of pHM6-4Cysl-SUMO-1 and pHM6-4Cys2-SUMO-l into HeLa cells --- p.184 / Chapter 3.1.3 --- Reagents and buffers --- p.184 / Chapter 3.1.3.1 --- Reagents and buffers for Lumio´ёØ in-gel labeling --- p.184 / Chapter 3.1.3.2 --- Reagents and buffers for Lumio´ёØ in cell labeling --- p.185 / Chapter 3.1.3.3 --- Reagents and buffers for immunostaining --- p.186 / Chapter 3.2 --- METHODS --- p.187 / Chapter 3.2.1 --- Molecular cloning of tetracysteine-tagged SUMO (4Cys-SUMO) into pET-28m and pHM6 vectors --- p.187 / Chapter 3.2.1.1 --- Design of primers and oligonucleotides encoding tetracysteine tag --- p.187 / Chapter 3.2.1.1.1 --- For 4Cysl-SUMO-1 --- p.187 / Chapter 3.2.1.1.2 --- For 4Cys2-SUMO-l --- p.188 / Chapter 3.2.1.2 --- DNA amplification of 4Cysl-SUMO-1 by Polymerase chain reaction (PCR) --- p.189 / Chapter 3.2.1.3 --- Restriction digestion of vectors and purified PCR products of 4Cysl-SUMO-1 --- p.191 / Chapter 3.2.1.4 --- Ligation of 4Cysl-SUMO into expression vector pET-28m and pHM6 --- p.191 / Chapter 3.2.1.5 --- Restriction digestion of pET-28m-SUMO and pHM6-SUMO for ligation with 4Cys2 oligos --- p.192 / Chapter 3.2.1.6 --- Ligation of 4Cys2 oligos to the digested pET-28m-SUMO and pHM6-SUMO plasmids --- p.193 / Chapter 3.2.1.6.1 --- Self-annealing of the 4Cys oligonucleotides --- p.193 / Chapter 3.2.1.6.2 --- Phosphorylation of ds 4Cys2 oligos and ligation to the plasmids --- p.193 / Chapter 3.2.2 --- Expression and purification of pET-28m-4Cys 1 -SUMO-1 and pET-28m-4Cys2-SUMO-1 in E.coli expression system --- p.195 / Chapter 3.2.3 --- Immunohistochemistry (IHC) staining of endogenous SUMO in HeLa cells --- p.196 / Chapter 3.2.4 --- In-cell labeling of 4Cysl/2-SUMO with Lumio´ёØ Reagent --- p.197 / Chapter 3.2.4.1 --- Preparation --- p.197 / Chapter 3.2.4.2 --- In-cell Lumio´ёØ labeling --- p.198 / Chapter 3.2.4.3 --- Detection and imaging of the labeled cells --- p.199 / Chapter 3.2.5 --- In-gel labeling of 4Cysl/2-SUMO with Lumio´ёØ Reagent --- p.199 / Chapter 3.2.5.1 --- Lumio´ёØ in-gel labeling --- p.199 / Chapter 3.2.5.2 --- Visualization and imaging of the labeled gel --- p.200 / Chapter a. --- UV illumination at 302 nm --- p.200 / Chapter b. --- Typhoon Trio TMLaser-scanning at 532 nm --- p.201 / Chapter 3.2.5.3 --- Detection limit of fluorescent 4Cys2-SUMO-l in SDS-PAGE --- p.201 / Chapter 3.2.5.4 --- In-gel labelling in two-dimensional electrophoresis (2-DE) --- p.202 / Chapter 3.2.5.4.1 --- Modification of equilibration buffer before SDS-PAGE --- p.202 / Chapter 3.3 --- RESULTS --- p.203 / Chapter 3.3.1 --- Adoption of old version of 4Cys-tag (4Cys 1) in SUMO study --- p.203 / Chapter 3.3.1.1 --- Construction of recombinant pET-28m-4Cys 1 -SUMO-1 and pHM6-4Cysl-SUMO-1 --- p.203 / Chapter 3.3.1.2 --- In vivo HA-4Cysl-SUMO-1 Lumio´ёØ labelling --- p.205 / Chapter 3.3.1.3 --- Immunohistochemistry (IHC) staining of endogenous SUMO in HeLa cells --- p.207 / Chapter 3.3.1.4 --- Expression and purification of His6-4Cysl-SUMO-1 --- p.208 / Chapter 3.3.1.5 --- Validation of 4Cys1-SUMO-1 conjugate by Lumio´ёØ in-gel labeling --- p.211 / Chapter 3.3.2 --- Adoption of a modified version of 4Cys-tag (4Cys2) in SUMO study --- p.213 / Chapter 3.3.2.1 --- Construction of recombinant pET-28m-4Cys2-SUMO-l and pHM6-4Cys2-SUMO-l --- p.213 / Chapter 3.3.2.2 --- In vivo HA-4Cys2-SUMO-l Lumio´ёØ labelling --- p.216 / Chapter 3.3.2.3 --- Expression and purification of His6-4Cys2-SUMO-1 --- p.219 / Chapter 3.3.2.4 --- Validation of 4Cys2-SUMO-l conjugate Lumio´ёØ in-gel labeling --- p.221 / Chapter 3.3.3 --- 2As-4Cys labeling in two-dimensional electrophoresis (2-DE) --- p.223 / Chapter 3.3.3.1 --- Detection limit of 4Cys2-SUMO-l in SDS-PAGE --- p.224 / Chapter 3.3.3.2 --- Lumio´ёØ labeling in 2-DE --- p.226 / Chapter 3.4 --- DISCUSSION --- p.232 / Chapter Chapter IV --- Conclusion and Future Perspectives --- p.242 / Chapter 4.1 --- Conclusion on proteomic study of SUMOylation --- p.242 / Chapter 4.2 --- Future perspectives of proteomic study of SUMOylation --- p.245 / Chapter 4.2.1 --- In vitro study --- p.245 / Chapter 4.2.2 --- In vivo study --- p.246 / Chapter 4.3 --- Conclusion of the investigation of biarsencial-tetracysteine (2As-4Cys) system application on SUMO study --- p.247 / Chapter 4.4 --- Future perspectives of the application of 2As-4Cys system application on SUMO study --- p.249 / Chapter 4.4.1 --- In cell study --- p.249 / Chapter 4.4.2 --- In gel study --- p.250 / Appendices --- p.251 / Chapter 1. --- Genotype of E.coli strains --- p.251 / Chapter 2. --- Vector maps --- p.252 / Chapter a. --- Vector map and MCS of pET-28a --- p.252 / Chapter b. --- Vector map and MCS of pHM6 --- p.253 / Chapter c. --- Vector information of pTwo-E --- p.254 / Chapter 3. --- Primers used in this study --- p.255 / Chapter 4. --- Nikon TE2000 filter sets spectrums --- p.257 / Chapter a. --- FITC/GFP filter set --- p.257 / Chapter b. --- RFP filter set --- p.257 / Chapter c. --- UV/DAPI/Hoechst filter set --- p.258 / Chapter 5. --- Akt signalling pathway diagram --- p.259 / Chapter 6. --- DNA sequence of SUMOs and 4Cys2 oligonucleotide --- p.260 / Chapter 7. --- Electrophoresis markers --- p.261 / References --- p.263

Background: We aimed to increase the knowledge regarding the familial arrhythmogenic disorder Long QT Syndrome (LQTS) and its recessive variant Jervell and Lange-Nielsen Syndrome (JLNS) in Sweden, including prevalences and clinical phenotypes. A specific focus was directed towards two KCNQ1 mutations –p.Y111C and p.R518X- commonly identified in Swedish LQTS index cases. Methods: Cases and families with LQTS (p.Y111C or p.R518X) and JLNS were recruited via regional clinical practices, national referrals to the Clinical Genetics laboratory, Umeå University Hospital, and a national inventory. Molecular genetics methods were used for case ascertainment. Clinical data was obtained via medical records, a questionnaire, and/or an interview. Electrocardiograms were manually assessed. In p.R518X heterozygotes intra-familial phenotypic variability (QTc and cardiac events) was assessed by analysis of sequence variants (modifier genes). The origins of the mutations p.Y111C and p.R518X were investigated using genealogical and haplotype analysis (microsatellite markers). In families sharing a common haplotype mutation age and associated prevalence was analyzed using ESTIAGE and DMLE computer software. Results: We identified p.Y111C (170 mutation-carriers) and p.R518X (101 mutation-carriers) as two major causes of LQTS/JLNS in Sweden. LQTS phenotype was revealed to be relatively benign in p.Y111C and p.R518X (annual incidence of life-threatening cardiac events, before therapy 0.05% and 0.04%, respectively). Gender-specific effects of genetic modifiers on phenotypic expression were seen. A founder origin, approximately 600-700 years ago in two northern river valleys was established for p.Y111C and p.R518X, and a high prevalence of LQTS founder descendants suggested. A minimum JLNS prevalence of 1:200 000 in preadolescent Swedish children was revealed. JLNS phenotype was mainly severe, with a cumulative incidence of life-threatening cardiac events of 53% (annual incidence rate before therapy 5%) and four sudden deaths. Possible founder effects regarding four KCNQ1 mutations; p.Y111C (8%), p.R518X (50%), c.572_576del (17%) and p.Q530X (8%) together explained 83% of the JLNS mutation-spectrum in Sweden, consisting of 8 KCNQ1 mutations. Conclusion: The high prevalence of p.Y111C- and p.R518X-related LQTS as well as JLNS revealed in Sweden could be explained by the combination of mild clinical phenotypes in heterozygotes and strong founder effects present during the population development of northern Sweden. Increased knowledge regarding the occurrence of LQTS and JLNS as well as mutation- and/or genotype-specific data constitute prerequisites for possible improvement of patient management.

Introdução: A doença de Machado-Joseph (DMJ) ou ataxia espinocerebelar tipo 3 (SCA3) é causada por uma expansão de trinucleotídeos CAG no gene ATXN3, que leva à degeneração de múltiplos sistemas neurológicos. Seu curso é invariavelmente progressivo, não havendo tratamento específico. Objetivos: Descrever novos biomarcadores, aspectos não motores e definir quais escalas clínicas devem ser utilizadas como desfechos principais nos futuros ensaios clínicos randomizados (ECR) para a DMJ/SCA3. Além de avaliar se o tratamento com carbonato de lítio é seguro e efetivo em reduzir a progressão desta condição. Métodos: Em estudo caso-controle avaliamos: 1) a relação dos sintomas depressivos na DMJ/SCA3, pelo inventário de Beck (BDI), com aspectos de gravidade clínica e molecular; 2) alterações no índice de massa corporal (IMC) e sua correlação com aspectos clínico-moleculares e de neuroimagem; e 3) o Sistema Insulina/ IGF-1 (IIS) e o potencial de seus componentes como biomarcadores. Fizemos uma revisão sistemática sobre os aspectos psicométricos das escalas clínicas de SCAs já descritas, para em seguida iniciarmos um ECR, duplo-cego, paralelo, placebo-controlado de fase 2/3. Para este estudo foram randomizados 62 pacientes com diagnóstico molecular prévio de DMJ/SCA3 com marcha independente e ≤ 10 anos de doença (1:1) para tratamento com carbonato de lítio (0.5-0.8mEq/L) ou placebo. Resultados: Os escores do BDI foram mais elevados na DMJ/SCA3 (p= 0.012) e correlacionaram-se significativamente apenas com as escalas SARA (R=0.359, p=0.01) e NESSCA (R=0.412, p=0.003). Os pacientes com DMJ/SCA3 (N=46) apresentaram IMC menor (24.4 ± 4.1) do que os indivíduos controle (N=42, 27.1± 4.5, p=0.01), havendo correlação inversa (R=−0.396, p=0.015) entre o IMC e o tamanho da sequencia repetitiva CAG (CAGn). Encontramos uma maior sensibilidade periférica à insulina (HOMA2-%S, p=0.003, corrigido pelo IMC) e níveis séricos mais elevados da proteína ligante do IGF-1, IGFBP-1 (p=0.001) na DMJ/SCA3. A IGFBP1 correlacionou-se diretamente à CAGn (R=0.452; p = 0.006) e a sensibilidade à insulina inversamente à idade de início dos sintomas (R=-0.444; P = 0.003). Concluímos, na revisão sistemática, que as escalas semi-quantitativas SARA e NESSCA, e as quantitativas SCAFI e CCFS seriam os melhores desfechos para um ECR. O uso de lítio foi seguro após 24 semanas de tratamento, não havendo diferenças no número total de eventos adversos entre os grupos lítio (50,3%) e placebo (49,7%, p=1.00). O grupo placebo apresentou maior progressão (que não foi significativa) nos escores NESSCA (0.35 pontos, 95% IC -1.0 a 1.7, p=0.222, desfecho primário de efetividade) e SARA (0.96 pontos, 95% IC -0.46 a 2.38, p=0.329), após 48 semanas de tratamento. A gravidade da ataxia de marcha (p=0.008), as provas funcionais quantitativas: PATA rate (p=0.002) e Click Test ND (p=0.023), e os escores compostos SCAFI (p=0.015) e CCFS (p=0.029) apresentaram menor progressão no grupo tratado com lítio durante as 48 semanas. Conclusão: Os resultados destes estudos ajudam no entendimento da depressão e alterações nutricionais da DMJ/SCA3 e apontam a IGFBP-1 como biomarcador e a sensibilidade periférica insulínica como modificador do fenótipo. Houve efetividade do tratamento com carbonato de lítio nos desfechos secundários do ECR, sendo necessária confirmação por ensaios clínicos multicêntricos. / Background: Machado-Joseph disease (MJD) or spinocerebellar ataxia type 3 (SCA3) is caused by a CAG repeat expansion at ATXN3 gene, leading to progressive degeneration of multiple neurological systems. MJD/SCA3 is an invariably progressive disorder, with no current treatment. Objectives: To describe new disease biomarkers, non-motor aspects and to define the clinical SCA scales to be utilized as main outcomes in future randomized controlled trials (RCT) on MJD/SCA3. And further assess safety and effectiveness of lithium carbonate in reducing the progression of this condition. Methods: We performed a case-control study to evaluate: 1) the relation of MJD/SCA3 depressive symptoms, through Beck depression Inventory (BDI), with other clinical and molecular findings; 2) the Body Mass Index (BMI) of MJD/SCA3 patients and the correlation with other clinical, molecular and neuroimaging findings; and 3) the Insulin/IGF-1 system (IIS) in MJD/SCA3 and the possible biomarker properties of its components. We further performed a systematic review on the psychometric properties of the described SCAs scales in order to initiate the double-blind, parallel, placebo-controlled phase 2/3 clinical trial. 62 independently ambulatory MJD/SCA3 patients with ≤ 10 years of disease duration were randomly assigned in the RCT (1:1) to lithium (0.5-0.8mEq/L) or placebo. Results: BDI scores were higher in MJD/SCA3 patients (p= 0.012), with significant correlations only with the scales SARA (R=0.359, p=0.01) and NESSCA (R=0.412, p=0.003). MJD/SCA3 patients (N=46) presented lower BMI (24.4 ± 4.1) than control individuals (N=42, 27.1± 4.5, p=0.01). BMI correlated inversely with the length of the expanded CAG repeat (CAGn). We found higher peripheral sensitivity to insulin (HOMA2-%S, p=0.003, corrected for BMI) and serum levels of the IGF-1 binding protein, IGFBP-1 (p=0.001) in MJD/SCA3. IGFBP-1 correlated with CAGn (R=0.452; p = 0.006) and insulin sensitivity with the age of disease onset (R=-0.444; P = 0.003). In the systematic review we concluded that the semiquantitative SCA scales SARA and NESSCA and the quantitative instruments SCAFI and CCFS would be the most appropriate outcomes for the RCT. After 24 weeks, there were no differences in the number of adverse events in lithium (50.3%) and placebo (40.7%) groups (p=1.00) in the RCT. The placebo group presented a non-significant faster progression on NESSCA (0.35 points, 95% CI -1.0 to 1.7, p=0.612, primary effectiveness outcome) and SARA (0.96 points, 95% CI -0.46 to 2.38, p=0.186), after 48 weeks of treatment. Gait ataxia severity (p=0.008), the quantitative performance tasks: PATA rate (p=0.002) and Click Test ND (p=0.023), and the composite scores SCAFI (p=0.015) and CCFS (p=0.029) presented a slower progression under lithium therapy in the overall 48 weeks period. Conclusion: These studies added to the understanding of depressive and nutritional manifestations of MJD/SCA3 and points IGFBP-1 as a biomarker and peripheral insulin sensitivity as a disease phenotype modifier. The effectiveness of lithium carbonate treatment shown in secondary outcomes of the RCT opened a perspective for an effective therapy for this untreatable disorder that must be confirmed by large multicentric clinical trials.

No description available.

Le développement des lubrifiants est un véritable levier pour les constructeurs automobiles et les pétroliers pour minimiser les pertes d'énergie dues aux frottements dans les moteurs. La viscosité est le principal paramètre sur lequel les formulateurs peuvent jouer pour abaisser les frottements. Cette thèse porte sur l'étude du rôle et des actions des additifs améliorants de viscosité (AVI) dans les lubrifiants moteur. L'objectif de cette thèse est de corréler l'étude portée à l'échelle moléculaire aux propriétés macroscopiques ainsi qu'aux performances des lubrifiants moteur pour pouvoir orienter les formulateurs vers une ou des molécules cibles qui permettront de répondre le mieux possible à ces problématiques. Ce travail est consacré à des poly-diène-styrène hydrogénés (P-diène-SH) et des copolymères éthylène propylène (EPC). Dans un premier temps, des études structurales des polymères AVI et rhéologiques des solutions ont permis de mettre en évidence l'influence des différentes chimies et structures des polymères sur leurs propriétés rhéologiques. Cette étude a porté sur une large gamme de températures (-20 à +135°C), taux de cisaillement (0 à 107s-1) et concentrations permettant de caractériser la configuration des polymères dans des conditions correspondant à l’application. Dans un second temps, ces propriétés rhéologiques ont été corrélées avec les coefficients de frottement et les épaisseurs de film centrales dans un contact de type sphère/plan en tribologie.Enfin, la capacité des chaînes de ces polymères à se rompre sous la contrainte d’un fort taux de cisaillement en écoulement pulsé ou continu a été étudiée et reliée à la configuration des polymères AVI en solution ainsi que leurs structures. L’ensemble de ces données a été utilisé pour proposer une structure chimique et une architecture présentant des propriétés AVI, une bonne résistance mécanique et un comportement tribologique satisfaisant. / The development of lubricants is a real challenge for the automotive and the petroleum industries to reduce the energy losses in engines due to frictions. The viscosity is the main parameter that the lubricant formulators can vary to reduce the frictions. This PhD deals with the role and mode of actions of viscosity modifier polymers (VM polymers) in lubricants.The purpose of this PhD is to correlate the study at the molecular scale with the macroscopic properties and the lubricant performances in order to orient the formulators towards one or several target molecules which could present the best properties.This work consisted in characterizing hydrogenated Poly-diene-styrene (P-diene-SH) and ethylene-propylene-copolymers (EPC).First, studies on the structure of VM polymers and on rheological properties of the solutions have shown the influence of the different chemical structures and polymer architectures on their rheological properties. This study was carried out on a large scale of temperatures (-20 à +135°C), shear rates (0 à 107s-1) and concentrations leading to characterizations under conditions corresponding to practical conditions.Secondly, these rheological properties were correlated with frictions coefficients and the film thickness in a sphere/plate contact in tribology.Finally, the ability of the polymer chains to break when a high shear rate was applied in a continuous or pulsed flow was studied and related to the chains configurations of the VM polymer and their structure.All these data were further used to propose a chemical structure and a polymer architecture leading to viscosity improved properties, a good resistance to degradation and a satisfactory behavior in tribology.

Introdução: A doença de Machado-Joseph (DMJ) ou ataxia espinocerebelar tipo 3 (SCA3) é causada por uma expansão de trinucleotídeos CAG no gene ATXN3, que leva à degeneração de múltiplos sistemas neurológicos. Seu curso é invariavelmente progressivo, não havendo tratamento específico. Objetivos: Descrever novos biomarcadores, aspectos não motores e definir quais escalas clínicas devem ser utilizadas como desfechos principais nos futuros ensaios clínicos randomizados (ECR) para a DMJ/SCA3. Além de avaliar se o tratamento com carbonato de lítio é seguro e efetivo em reduzir a progressão desta condição. Métodos: Em estudo caso-controle avaliamos: 1) a relação dos sintomas depressivos na DMJ/SCA3, pelo inventário de Beck (BDI), com aspectos de gravidade clínica e molecular; 2) alterações no índice de massa corporal (IMC) e sua correlação com aspectos clínico-moleculares e de neuroimagem; e 3) o Sistema Insulina/ IGF-1 (IIS) e o potencial de seus componentes como biomarcadores. Fizemos uma revisão sistemática sobre os aspectos psicométricos das escalas clínicas de SCAs já descritas, para em seguida iniciarmos um ECR, duplo-cego, paralelo, placebo-controlado de fase 2/3. Para este estudo foram randomizados 62 pacientes com diagnóstico molecular prévio de DMJ/SCA3 com marcha independente e ≤ 10 anos de doença (1:1) para tratamento com carbonato de lítio (0.5-0.8mEq/L) ou placebo. Resultados: Os escores do BDI foram mais elevados na DMJ/SCA3 (p= 0.012) e correlacionaram-se significativamente apenas com as escalas SARA (R=0.359, p=0.01) e NESSCA (R=0.412, p=0.003). Os pacientes com DMJ/SCA3 (N=46) apresentaram IMC menor (24.4 ± 4.1) do que os indivíduos controle (N=42, 27.1± 4.5, p=0.01), havendo correlação inversa (R=−0.396, p=0.015) entre o IMC e o tamanho da sequencia repetitiva CAG (CAGn). Encontramos uma maior sensibilidade periférica à insulina (HOMA2-%S, p=0.003, corrigido pelo IMC) e níveis séricos mais elevados da proteína ligante do IGF-1, IGFBP-1 (p=0.001) na DMJ/SCA3. A IGFBP1 correlacionou-se diretamente à CAGn (R=0.452; p = 0.006) e a sensibilidade à insulina inversamente à idade de início dos sintomas (R=-0.444; P = 0.003). Concluímos, na revisão sistemática, que as escalas semi-quantitativas SARA e NESSCA, e as quantitativas SCAFI e CCFS seriam os melhores desfechos para um ECR. O uso de lítio foi seguro após 24 semanas de tratamento, não havendo diferenças no número total de eventos adversos entre os grupos lítio (50,3%) e placebo (49,7%, p=1.00). O grupo placebo apresentou maior progressão (que não foi significativa) nos escores NESSCA (0.35 pontos, 95% IC -1.0 a 1.7, p=0.222, desfecho primário de efetividade) e SARA (0.96 pontos, 95% IC -0.46 a 2.38, p=0.329), após 48 semanas de tratamento. A gravidade da ataxia de marcha (p=0.008), as provas funcionais quantitativas: PATA rate (p=0.002) e Click Test ND (p=0.023), e os escores compostos SCAFI (p=0.015) e CCFS (p=0.029) apresentaram menor progressão no grupo tratado com lítio durante as 48 semanas. Conclusão: Os resultados destes estudos ajudam no entendimento da depressão e alterações nutricionais da DMJ/SCA3 e apontam a IGFBP-1 como biomarcador e a sensibilidade periférica insulínica como modificador do fenótipo. Houve efetividade do tratamento com carbonato de lítio nos desfechos secundários do ECR, sendo necessária confirmação por ensaios clínicos multicêntricos. / Background: Machado-Joseph disease (MJD) or spinocerebellar ataxia type 3 (SCA3) is caused by a CAG repeat expansion at ATXN3 gene, leading to progressive degeneration of multiple neurological systems. MJD/SCA3 is an invariably progressive disorder, with no current treatment. Objectives: To describe new disease biomarkers, non-motor aspects and to define the clinical SCA scales to be utilized as main outcomes in future randomized controlled trials (RCT) on MJD/SCA3. And further assess safety and effectiveness of lithium carbonate in reducing the progression of this condition. Methods: We performed a case-control study to evaluate: 1) the relation of MJD/SCA3 depressive symptoms, through Beck depression Inventory (BDI), with other clinical and molecular findings; 2) the Body Mass Index (BMI) of MJD/SCA3 patients and the correlation with other clinical, molecular and neuroimaging findings; and 3) the Insulin/IGF-1 system (IIS) in MJD/SCA3 and the possible biomarker properties of its components. We further performed a systematic review on the psychometric properties of the described SCAs scales in order to initiate the double-blind, parallel, placebo-controlled phase 2/3 clinical trial. 62 independently ambulatory MJD/SCA3 patients with ≤ 10 years of disease duration were randomly assigned in the RCT (1:1) to lithium (0.5-0.8mEq/L) or placebo. Results: BDI scores were higher in MJD/SCA3 patients (p= 0.012), with significant correlations only with the scales SARA (R=0.359, p=0.01) and NESSCA (R=0.412, p=0.003). MJD/SCA3 patients (N=46) presented lower BMI (24.4 ± 4.1) than control individuals (N=42, 27.1± 4.5, p=0.01). BMI correlated inversely with the length of the expanded CAG repeat (CAGn). We found higher peripheral sensitivity to insulin (HOMA2-%S, p=0.003, corrected for BMI) and serum levels of the IGF-1 binding protein, IGFBP-1 (p=0.001) in MJD/SCA3. IGFBP-1 correlated with CAGn (R=0.452; p = 0.006) and insulin sensitivity with the age of disease onset (R=-0.444; P = 0.003). In the systematic review we concluded that the semiquantitative SCA scales SARA and NESSCA and the quantitative instruments SCAFI and CCFS would be the most appropriate outcomes for the RCT. After 24 weeks, there were no differences in the number of adverse events in lithium (50.3%) and placebo (40.7%) groups (p=1.00) in the RCT. The placebo group presented a non-significant faster progression on NESSCA (0.35 points, 95% CI -1.0 to 1.7, p=0.612, primary effectiveness outcome) and SARA (0.96 points, 95% CI -0.46 to 2.38, p=0.186), after 48 weeks of treatment. Gait ataxia severity (p=0.008), the quantitative performance tasks: PATA rate (p=0.002) and Click Test ND (p=0.023), and the composite scores SCAFI (p=0.015) and CCFS (p=0.029) presented a slower progression under lithium therapy in the overall 48 weeks period. Conclusion: These studies added to the understanding of depressive and nutritional manifestations of MJD/SCA3 and points IGFBP-1 as a biomarker and peripheral insulin sensitivity as a disease phenotype modifier. The effectiveness of lithium carbonate treatment shown in secondary outcomes of the RCT opened a perspective for an effective therapy for this untreatable disorder that must be confirmed by large multicentric clinical trials.