Na dentina, a matriz orgânica desmineralizada tem um papel protetor contra desafios erosivos subsequentes. Porém, essa camada pode ser degradada por proteases, como as metaloproteinases da matriz (MMPs) e cisteína catepsinas (CCs). Recentemente, o uso de inibidores de proteases da matriz surgiu como uma importante ferramenta preventiva contra a erosão dentinária. Entretanto, o(s) mecanismo(s) exato(s) pelo(s) qual(is) os inibidores de proteases podem prevenir a erosão dentinária, bem como os tipos de proteases mais envolvidas neste processo ainda não são completamente conhecidos. O projeto foi desenvolvido em 2 subprojetos, com os seguintes objetivos: A)Subprojeto 1:Avaliar o papel das proteases na progressão da erosão dentária; B)subprojeto 2: Testar o potencial inibitório do NaF em CCs dentinárias. Para cumprir esses objetivos, foram utilizadas dentina de terceiros molares humanos para a preparação dos espécimes. A)Subprojeto1:Blocos de dentina (4 X 4 x 2 mm) (n=119) foram obtidos de raízes. Os espécimes foram divididos em 7 grupos de acordo com o seu tratamento (E-64, inibidor especifico II de catepsinas B, clorexidina, galardina NaF, placebo) ou sem tratamento, géis foram aplicados uma única vez sobre a superfície e feito o desafio erosivo (90s, 4x por dia por 5 dias) e feita analise perfilométrica. Os espécimes foram incubadas em solução contendo colagenase de Clostridium histolyticum tipo VII por 96hrs e então feita uma segunda analise perfilometrica para se determinar a espessura da MOD. Dois espécimes foram separados para análise de microscopia eletrônica de varredura. B)Subprojeto 2: Palitos de dentina (6 mm X 2 mm X 1 mm) (n=60) foram cortados da porção médio coronária dos dentes e completamente desmineralizados por imersão em EDTA 0,5 M (pH7,4) por 30 dias e lavados em água deionizada sob constante agitação a 4ºC por 72 h. Os espécimes foram divididos em 6 grupos (E-64, NaF e controle negativo, pH 5,5 ou 7,2) e incubados em saliva artificial contendo seus respectivos inibidores por 24 h 7 dias e 21 dias; ao termino de cada período, os espécimes eram pesados para avaliar a perda de massa e analisada a presença de CTX. A)Subprojeto 1: a perda de tecido desmineralizado (m, média± SD) foi: CHX 8,4±1,7b, Gala 8,6±1,9b, IECB 9,6±1,4a, E64 9,9±1,3a, NaF 9,9±1,7a, P 10,9±2,2a, ST 11,0±1,5a. A perda de tecido mineralizado foi: CHX 15,4±2,2b, Gala 16,0±1,8b, IECB 17,6±2,4a, E64 17,6±2,0a, NaF 17,3±2,8a, P 19,1±2,1a, ST 18,9±2,4a. Os inibidores de MMP reduziu significativamente a perda de matriz orgânica e tecido mineralizado em comparação com os outros grupos (p<0,05). Não foi achada diferença significante entre a espessura da matriz orgânica desmineralizada remanescente (p=0,845). B)Subprojeto 2: Na perda de massa houve diferença significante em relação ao inibidor (F=20,047, p<0,0001) e tempo de incubação (F=222,462, p<0,0001) com significante interação entre esses critérios, nos período de menor tempo de incubação, a perda foi similar para todos os grupos testados, no período de maior tempo de incubação, o grupo contendo NaF demostrou os melhores resultados. Na analise de CTX, houve diferença significante em relação aos inibidores (F46,543, p<0,0001), pH (F=14,836, p<0,0004) e tempo de incubação (F=161,438, p<0,0001) com significante interação entre esses critérios, como ocorrido na perda de massa, não houve diferença estatística nos períodos de menor incubação. No período de maior tempo de incubação, mais uma vez o grupo NaF mostrou os melhores resultados. No valor acumulado de CTX, os grupos E64 e controle negativo tiveram os maiores valores de CTX acumulado, o grupo NaF, independente do pH mostrou redução significante em relação aos demais grupos. Após analise dos resultados dos dois subprojetos, podemos indicar que as MMPs são as proteases de maior importância na progressão da erosão dentinária, assim, sua inibição é de maior importância para a redução desta patologia. Mesmo as CCs não exercendo papel direto para a progressão da erosão, elas são efetivas na cascata da ativação de outras proteases, como as próprias MMPs. Com isso, sua inibição também pode ser importante para a redução indireta da progressão da erosão. Neste presente estudo, pudemos comprovar que o NaF tem potencial inibitório sobre as CCs dentinárias, assim, sugerindo um novo inbidor de CCs. Com os resultados deste estudo, podemos afirmar que as MMPs são as principais proteases na progressão da erosão dentinária e que o NaF tem potencial inibitório nas CCs dentinárias. / In the dentine, the demineralized organic matrix has a protector part against the following erosive challenges. Nevertheless, this layer can be degraded by proteases, like the matrix metalloproteinases (MMPS) and cystein cathepsins (CCs). Recently, the use of proteases of the matrix´s inhibitors, emerged as an important preventive tool against the dentinária erosion. However, the exact mechanisms from which the inhibitors of the proteases may prevent the dentin erosion, as much as the kinds of proteases more involved in this process are not completely known yet. Therefore, the general objective of this project was to investigate the part of the two main proteases of the matrix (MMPs and CCs) in the dental erosion. The project was developed in 2 subprojects, with the following objectives: A)Subproject 1: Evaluate the part of the proteases in the progression of the dental erosion; B)subproject 2: To test the NaF inhibitory potencial in the dentin CCs. To accomplish these objectives, human third molar dentin were used for the preparation of the specimens, obtained in the surgery and urgency clinics of FOB-USP (subproject 1) or granted by the University of Oulu (subproject 2). A) Subproject 1: Dentine blocks 4 X 4 X 2 mm) (n=119) were obtained from the roots of the obtained teeth. The specimens were divided in 7 groups according with their treatment. Gels containing inhibitors (E-64, specific cathepsin B inhibitor II, chlorhexidine, galardin NaF, placebo), or without treatment, were produced, applied only one time over the surface and made the erosive challenge (90s, 4x a day for 5 days) and made profilometric analysis. The specimens were incubated in a solution containing collagenase of Clostridium histolyticum type VII for 96 hours and then a second profilometric analysis was made to determine the thickness of the MOD. Two specimens were separated for the electronic microscopy scan analysis. B) Subproject 2: Dentine sticks (6 mm X 2 mm X 1 mm) (n=60) were cut from the medium coronary portion of the teeth and completely demineralized by immersion in EDTA 0,5 M (pH7,4) ifor 30 days and washed in deionized water under constant agitation in 4º C for 72 hours. The specimens were divided in 6 groups (divided by inhibitors: E-64, NaF and negative control, pH 5,5 or 7,2) and incubated in artificial saliva containing their respective inhibitors for 24 hours, 7 days and 21 days; by the end of each period, the specimens were weighted to evaluate the loss of mass and analised the presence of CTX. A)Subproject 1: the loss of demineralized tissue (m, média± SD) was : CHX 8,4±1,7b, Gala 8,6±1,9b, IECB 9,6±1,4a, E64 9,9±1,3a, NaF 9,9±1,7a, P 10,9±2,2a, ST 11,0±1,5a. The loss of demineralized tissue was: CHX 15,4±2,2b, Gala 16,0±1,8b, IECB 17,6±2,4a, E64 17,6±2,0a, NaF 17,3±2,8a, P 19,1±2,1a, ST 18,9±2,4a. The MMP inhibitors reduced significantly the loss of organic matrix and demineralized tissue in comparison with other groups (p<0,05). There was no significant difference found between the thickness of the remaining demineralized organic matrix.(p=0,845). B)Subproject: In the loss of mass, there was a significant difference in relation to the inhibitor (F=20,047, p<0,0001) and incubation time (F=222,462, p<0,0001) with significant interaction between these criteria, in the periods of lesser time of incubation, the loss was similar for all the tested groups, in the period of higher time of incubation, the group containing NaF demonstrated the best results. In the analysis of CTX, there was significant difference in relation the inhibitors (F46,543, p<0,0001), pH (F=14,836, p<0,0004) and time of incubation (F=161,438, p<0,0001)with significant interaction between these criteria, as occurred in the mass loss, there was no statistic difference in the period of lesser incubation. In the period of higher time of incubation, once again, the NaF group demonstrated the best results. The CTX accumulated value, the E64 groups and negative control had the greater accumulated values of CTX, the NaF group, regardlessof the pH, demonstrated significant reduction in relation to the other groups. After the analysisof the results of both subprojects, we can indicate that the MMPs are the proteases of greater importance in the progression of the dentin erosion, thus, its inhibition is of graeter importance for the reduction of this pathology. Even the CCs don´t playing the part directly for the progression of erosion, they are effective in the cascade of the activation of other proteases, like the MMPs themselves. In this manner, its inhibition can also be important for the indirect reduction of the progression of the erosion. In this present study, we can prove that the NaF has inhibiting potential over the dentin CCs, thus, suggesting a new inhibitor of CCs. With the results of this study, we can affirm that the MMPs are the main proteases in the progression of the dentin erosion and that the NaF has inhibiting potential in the dentin CCs.

Les cancers du sein triple-négatif (TNBC) (RE-, RP-, HER2) représentent 15% des cas de cancer du sein. Les patientes atteintes de TNBC sont traitées uniquement par chimiothérapie. A l’heure actuelle, il n’existe aucune thérapie ciblée efficace. Malgré une chimiosensibilité initiale, les rechutes sont fréquentes. Ainsi de nouveaux traitements sont nécessaires pour soigner ces patientes. Dans le cancer du sein, l’aspartyl protéase cathepsine D (cath-D), un marqueur de mauvais pronostic, est surexprimée par les cellules cancéreuses et est hyper-secrétée dans le microenvironnement tumoral. La cath-D stimule la prolifération des cellules cancéreuses, la croissance invasive des fibroblastes, la croissance tumorale, l’angiogenèse tumorale et la formation des métastases. Différentes études ont mis en exergue le rôle oncogénique de la cath-D extracellulaire dans le cancer du sein, suggérant qu’elle serait une cible thérapeutique d’intérêt. Afin de neutraliser sélectivement la forme sécrétée de la cath-D, le laboratoire a généré des anticorps humains IgG1 dirigés contre la cath-D par un crible de phage display (International patent N° PCT/EP2016/061454).Les principaux objectifs de ma thèse ont été i) de valider la cath-D comme une cible extracellulaire d’intérêt pour les patientes atteintes de TNBC, ii) d’évaluer les effets thérapeutiques et iii) de caractériser les mécanismes d’action des anticorps humains anti-cath-D.Nous avons montré que des niveaux élevés d'ARNm de CTSD sont corrélés à une survie sans récidive plus courte. Par analyse protéomique et étude immunohistochimique anti-cath-D réalisée sur Tissue Micro-Array, nous avons observé que la cath-D extracellulaire est détectée dans le microenvironnement tumoral des TNBC contrairement au tissu mammaire normal. Nos résultats mettent ainsi en exergue que la cath-D serait un biomarqueur tumoral extracellulaire, suggérant que les patientes atteintes de TBNC pourraient bénéficier d’une thérapie par des anticorps anti-cath-D. Par des analyses de SPECT-CT (Single Photon Emission Computed Tomography) et de biodistribution, nous avons validé que les anticorps humains anti-cath-D, F1 et E2, s’accumulent dans les xénogreffes de la lignée TNBC MDA-MB-231 chez la souris athymique. Les anticorps F1 et E2 inhibent la croissance tumorale des xénogreffes MDA-MB-231 et améliorent la survie des souris athymiques. Notre meilleur anticorps anti-cath-D, F1, inhibe également la croissance tumorale de deux lignées de TNBC PDX (patient-tumor derived xenografts). Au niveau mécanistique, l’anticorps F1 module le microenvironnement immunitaire dans les tumeurs issues des xénogreffes MDA-MB-231. L’ensemble de nos résultats suggèrent qu’une immunothérapie avec des anticorps humains anti-cath-D pourrait être une nouvelle approche thérapeutique pour les patientes atteintes de TNBC. / Triple-negative breast cancer (TNBC) accounts for 15-20% of all breast cancer cases, and chemotherapy is the only available treatment. Thus identification of new therapeutic targets is required to improve TNBC outcome. In breast cancer, the aspartic protease cathepsin D (cath-D) is a marker of poor prognosis associated with metastatic risk. This protease is overexpressed by breast cancer cells and is abnormally hypersecreted into the tumor microenvironment. Cath-D affects both cancer and stromal cells in the breast tumor microenvironment by increasing the proliferation of breast cancer cells, fibroblast invasive outgrowth, tumor growth and angiogenesis, and metastasis formation. Many studies indicated that extracellular cath-D displays oncogenic activities, suggesting it could represent a novel therapeutic target in TNBC. In order to block its oncogenic actions, the laboratory generated human IgG1 antibodies against extracellular cath-D by phage display (International patent N° PCT/EP2016/061454). The aims of my PhD project was i) to validate the potential value of cath-D as a tumor-specific extracellular target in TNBC, ii) to evaluate the therapeutic activity, and iii) to characterize the mechanisms of action of these anti-cath-D human antibodies.We showed that elevated CTSD mRNA levels correlated with shorter recurrence-free survival. Using proteomics analysis and anti-cath-D immunohistochemistry performed on Tissue Micro-Array, we observed that extracellular cath-D was detected in the tumor microenvironment of TNBC, but not in matched normal breast stroma samples. Our results thus indicate that cath-D is a tumor cell-associated extracellular biomarker and strongly suggest that it could be a good candidate for antibody-based therapy in TNBC. We found that anti-cath-D human antibodies, F1 and E2, accumulated in TNBC MDA-MB-231 tumor xenografts in athymic mice by SPECT-CT (Single Photon Emission Computed Tomography) and biodistribution analysis. F1 and E2 antibodies inhibited tumor growth of MDA-MB-231 tumor xenografts and improved mice survival without apparent toxicity. F1, the best antibody candidate, inhibited tumor growth of two TNBC patient-derived xenografts (PDX). Mechanistically, F1 treatment modulates immune tumor microenvironment in the MDA-MB-231 tumor cell xenograft model. Together, our results indicate that antibody-based targeting of cath-D may have therapeutic efficacy for TNBC treatment.

O remodelamento ósseo é um processo metabólico, dentro do qual os osteoblastos e os osteoclastos, participam ativamente. Portanto, qualquer alteração neste equilíbrio, pode provocar uma modificação na densidade mineral do osso, situação observada em certas doenças osteolíticas como osteoporose, artrite reumatóide e periodontite. Nos últimos anos, há um crescente interesse em avaliar o papel da glicólise na proliferação, sobrevivência e diferenciação dos diferentes tipos celulares. Em particular, tem sido evidenciado o efeito regulador da frutose 1,6-bisfosfato (FBP), um intermediário da via glicolítica de alta energia. Considerando que ainda não existem dados na literatura que correlacionem a FBP com o funcionamento dos osteoclastos, este trabalho tem por finalidade avaliar seu papel na osteoclastogênese e reabsorção óssea in vitro. Para isso, pré-osteoclastos murinos derivados da medula óssea foram diferenciados em osteoclastos na presença de M-CSF, RANKL e duas concentrações da FBP (100 e 300 ?M). Os resultados obtidos amostram que a FBP inibe a diferenciação osteoclástica em uma relação dose-dependente, sem afetar a viabilidade celular. Observa-se também, que o tratamento com FBP diminui a expressão de genes marcadores como, Nfatc1, Trap e Catepsina K (p < 0.01) e das proteínas NFATc1 e catepsina K. Como também, promove uma redução na atividade reabsortiva dos osteoclastos depois de 96 h de cultura. O efeito inibidor da FBP não depende da atividade da piruvato quinase M2 (PKM2). Em conjunto, estes dados sugerem que a FBP é um metabolito regulador importante da osteoclastogênese, demonstrando ser um agente potencial para o tratamento de doenças osteolíticas. / Bone remodeling is a coordinated metabolic process, where the osteoblasts and osteoclasts participate actively. Therefore, any alteration in this balance may cause a change in the bone mineral density, a condition observed in certain bone loss-associated diseases such as osteoporosis, rheumatoid arthritis and periodontitis. Recently, there has been a growing interest in assessing the role of the glycolysis on the proliferation, survival, and differentiation of the different cell types. In particular, it has been demonstrated the protective effect of the Fructose 1,6-bisphosphate (FBP), a high-energy glycolytic intermediate. Considering that there is no evidence in the literature that associate FBP with the function of osteoclasts, this work aims to evaluate its role in osteoclastogenesis and bone resorption in vitro. To this end, murine bone marrow derived pre-osteoclasts were differentiated into osteoclasts in the presence of M-CSF, RANKL and two concentrations of FBP (100 and 300 ?M). The results showed that FBP inhibits the differentiation of osteoclasts in a dose dependent manner, without affecting the cell viability. It was also observed that the treatment with the FBP decreases the expression of marker genes such as Nfatc1, Trap and Cathepsin K (p < 0.01) and the NFATc1 and cathepsin K protein levels. As well, the treatment with FBP resulted in markedly fewer osteoclast activity after 96 h of culture. FBP osteoclast inhibitory effect does not involve Pyruvate Kinase M2 (PKM2) activity. Together, these data denote the important regulatory role of the FBP on osteoclastogenesis, proving to be a potential agent for the treatment of bone loss-associated diseases.

Les Glycosaminoglycannes (GAGs) sont une famille de polysaccharides principalement localisés au niveau de la matrice extracellulaire et de la membrane plasmique. Ils peuvent interagir avec des facteurs de croissance et des cytokines pour réguler leurs activités, participer à des transports protéiques à travers la membrane cellulaire, moduler les activités de certaines enzymes telles que les cathepsines (enzymes lysosomales). Toutes ces activités démontrent que les GAGs jouent des rôles primordiaux dans la régulation de la croissance, la différenciation, l'adhésion, l'inflammation et la mort cellulaire.L'implication de ces polysaccharides dans la régulation de l'apoptose via la voie mitochondriale n'a toujours pas été déterminée. Ici, nous démontrons dans un modèle cellulaire de fibroblastes de peau en culture primaire, soumis à un stress oxydatif par de l'H2O2, qu'un mimétique des GAGs, l'OTR4120, est capable de protéger la membrane du lysosome, de réduire le taux de ROS intracellulaires et d'inhiber la chute du potentiel de membrane mitochondrial et ainsi d'empêcher la libération du cytochrome c et l'activation des activités caspases-9 et -3 sans affecter la voie extrinsèque de l'apoptose. Les héparanes sulfates et les chondroïtines sulfates au contraire de l'héparine, ont montré un effet protecteur de l'apoptose en inhibant les protéines clefs de ce processus de mort cellulaire. Ainsi, les GAGs naturels et l'OTR4120 sont capables s'opposer à l'apoptose, en inhibant l'activité de la cathepsine D libérée dans le cytosol, empêchant ainsi l'activation de la voie intrinsèque de l'apoptose via la mitochondrie. Ces résultats ouvrent de nouveaux horizons notamment dans certaines maladies où le stress oxydatif est impliqué comme c'est le cas de certaines maladies neurodégénératives comme la maladie de Parkinson.La cause de la maladie de Parkinson (MP) qui affecte les neurones dopaminergiques demeure encore mystérieuse, bien que différentes preuves soutiennent les hypothèses impliquant des dysfonctionnements mitochondriaux et une accumulation d'α-synucléine comme étant les événements majeurs dans cette physiopathologie. Récemment, la cathepsine D a été impliquée dans des processus de mort cellulaire et montrée comme étant surexprimée dans des modèles de la MP. De plus, apparait être l'une des principales enzymes responsables de la dégradation de l'α-synucléine. Puisque les glycosaminoglycannes (GAGs) sont capables de réguler l'activité de la cathepsine D dans des cellules en culture dans une condition de stress, nous avons cherché à démontrer si GAGs pouvaient être localisés à un niveau intracellulaire, où ils pourraient interagir avec la cathepsine D et s'ils étaient capables de réguler l'accumulation/dégradation de l'α-synucléine. Ainsi nous avons mis en place un modèle cellulaire de la MP induit par le MPP+. Nous avons observé que l'expression génétique des enzymes de la biosynthèse des GAGs (HS2ST, HS6ST et CHST8) a été modifiée dans les cellules stressées par la neurotoxine et que leurs taux mesurés par leurs sulfates étaient augmentés plus précisément au niveau des HS. Au contraire, l'absence de GAGs sulfatés induit par le chlorate de sodium, un inhibiteur de la PAPs (donneur de sulfates), a permis d'augmenter l'activité de l'activité cathepsine D et également d'inhiber l'accumulation ou d'induire la dégradation de l'α-synucléine. Pour la première fois, il a été montré que les GAGs sont capables d'agir sur l'activité cathepsine D à l'intérieur de la cellule et de réguler l'accumulation/dégradation de l'α-synucléine. / Pas de résumé anglais

O remodelamento ósseo é um processo metabólico, dentro do qual os osteoblastos e os osteoclastos, participam ativamente. Portanto, qualquer alteração neste equilíbrio, pode provocar uma modificação na densidade mineral do osso, situação observada em certas doenças osteolíticas como osteoporose, artrite reumatóide e periodontite. Nos últimos anos, há um crescente interesse em avaliar o papel da glicólise na proliferação, sobrevivência e diferenciação dos diferentes tipos celulares. Em particular, tem sido evidenciado o efeito regulador da frutose 1,6-bisfosfato (FBP), um intermediário da via glicolítica de alta energia. Considerando que ainda não existem dados na literatura que correlacionem a FBP com o funcionamento dos osteoclastos, este trabalho tem por finalidade avaliar seu papel na osteoclastogênese e reabsorção óssea in vitro. Para isso, pré-osteoclastos murinos derivados da medula óssea foram diferenciados em osteoclastos na presença de M-CSF, RANKL e duas concentrações da FBP (100 e 300 ?M). Os resultados obtidos amostram que a FBP inibe a diferenciação osteoclástica em uma relação dose-dependente, sem afetar a viabilidade celular. Observa-se também, que o tratamento com FBP diminui a expressão de genes marcadores como, Nfatc1, Trap e Catepsina K (p < 0.01) e das proteínas NFATc1 e catepsina K. Como também, promove uma redução na atividade reabsortiva dos osteoclastos depois de 96 h de cultura. O efeito inibidor da FBP não depende da atividade da piruvato quinase M2 (PKM2). Em conjunto, estes dados sugerem que a FBP é um metabolito regulador importante da osteoclastogênese, demonstrando ser um agente potencial para o tratamento de doenças osteolíticas. / Bone remodeling is a coordinated metabolic process, where the osteoblasts and osteoclasts participate actively. Therefore, any alteration in this balance may cause a change in the bone mineral density, a condition observed in certain bone loss-associated diseases such as osteoporosis, rheumatoid arthritis and periodontitis. Recently, there has been a growing interest in assessing the role of the glycolysis on the proliferation, survival, and differentiation of the different cell types. In particular, it has been demonstrated the protective effect of the Fructose 1,6-bisphosphate (FBP), a high-energy glycolytic intermediate. Considering that there is no evidence in the literature that associate FBP with the function of osteoclasts, this work aims to evaluate its role in osteoclastogenesis and bone resorption in vitro. To this end, murine bone marrow derived pre-osteoclasts were differentiated into osteoclasts in the presence of M-CSF, RANKL and two concentrations of FBP (100 and 300 ?M). The results showed that FBP inhibits the differentiation of osteoclasts in a dose dependent manner, without affecting the cell viability. It was also observed that the treatment with the FBP decreases the expression of marker genes such as Nfatc1, Trap and Cathepsin K (p < 0.01) and the NFATc1 and cathepsin K protein levels. As well, the treatment with FBP resulted in markedly fewer osteoclast activity after 96 h of culture. FBP osteoclast inhibitory effect does not involve Pyruvate Kinase M2 (PKM2) activity. Together, these data denote the important regulatory role of the FBP on osteoclastogenesis, proving to be a potential agent for the treatment of bone loss-associated diseases.

Trypanosamas de diversas espécies podem infectar mamíferos de interesse econômico em todo o mundo. Trypanosoma vivax, T. evansi, T. equiperdum, T. congolense, T. b. brucei e T. simiae geram importantes doenças em ungulados na África, Ásia e Américas Central e do Sul; enquanto T. theileri e espécies relacionadas são pouco patogênicas. Compreender a epidemiologia e as interações parasita-vector-hospedeiro requer estudos de estrutura populacional, filogeográficos e de diversidade e relações filogenéticas entre isolados. Sequências de microssatelites e dos genes SSUrRNA, gGAPDH, CatL, ITS, SL, 5S, Cytb e ESAG6 mostraram ampla diversidade biológica e diferenciaram genótipos com associação geográfica e restrição de hospedeiros em T. theileri e espécies relacionadas. T. evansi mostrou importante heterogeneidade de sequências no gene ESAG6, enquanto populações de T. vivax muito divergentes foram observadas em regiões preservadas e com transmissão cíclica quando comparadas com a microheterogeneidade biológica de áreas de transmissão mecânica. / Trypanosames can infect diverse species of mammals of economic interest worldwide. Trypanosoma vivax, T. evansi, T. equiperdum, T. congolense, T. brucei brucei and T. simiae cause important diseases in ungulates in Africa, Asia and Central and South America, while T. theileri and related species are of low pathogenicity. Understanding the epidemiology and host-parasite-vector interactions requires studies of population structure, phylogeography and diversity and phylogenetic relationships among isolates. Microsatellite loci and sequences from genes SSUrRNA, gGAPDH, CatL, ITS, SL, 5S, Cytb and ESAG6 revealed high biological diversity and allowed differentiation of genotypes with geographic structure and host-restriction event in T. theileri and related species. T. evansi showed significant heterogeneity in ESAG6 sequences, while populations of T. vivax widely divergent were observed in pristine regions and cyclical transmission compared to the microheterogeneity showed by isolates from mechanical transmission areas.

Human mast cells have been associated with wound healing, allergies, inflammation, and defense against pathogens and have been detected in tissues close to blood vessels especially in the areas between the inside of the body and the external environment, such as the skin, lungs, digestive tract, mouth, and nose. Previous studies have shown that mast cells contain large granules filled with histamine, heparin, cytokines, eicosanoids, and the serine proteases, tryptase, Chymase, and cathepsin G (CatG). These proteases are stored and released from mast-cell granules upon activation by antigen binding to IgE immunoglobulins on the cell surface or by direct injury. In this study, chymase and CatG were expressed as active enzymes in the yeast Pichia pastoris by homologous recombination of the cDNA coding for the mature active proteases into the Pichia genome. Methanol induction resulted in the secretion of active enzyme into the Pichia growth media and increasing levels of enzyme were detected in the media for 5 days. Cells that secreted the highest levels of activity were selected by kinetic assay. Active chymase was purified from the culture media with a 22% yield of activity by a simple two-step procedure that involved hydrophobic-interaction chromatography followed by affinity chromatography on immobilized heparin. The major peak from the heparin column contained a single band of 30.6 kDa on SDS/PAGE. The purified recombinant human chymase was 96% active and the yield was 2.2 mg/l of growth media. Active CatG was partially purified from culture media using an ultrafiltration. Mass Spectroscopy (Maldi-Tof) data confirmed that the major protein band was CatG, resulting in the first active human CatG to be produced recombinantly. Additionally, the partially purified enzyme was active against both chymotrypsin and trypsin substrates, and its reaction with inhibitors was consistent with CatG. Although the protein yields were low, these results confirm that CatG was recombinantly expressed.

<p>Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an incidence of 1.5-2.7/100000 people/year. Today there is no cure for the disease and only symptomatic treatments are available. ALS progresses rapidly and only 50% of the patients are alive three years after the symptom debut. In ALS, the upper and lower motor neurons undergo degeneration in a process resembling apoptosis. This leads to muscle atrophy and paralysis. The causes of neuronal death are however unknown. In this thesis we have studied transgenic mice carrying human mutant superoxide dismutase, as a model for familial ALS. These mice develop ALS-like symptoms after four months of age with degeneration of the motor neurons. Our results show an involvement of endoplasmic reticulum stress, caspase-12, -9, -3 and procaspase-7 in the ALS mice spinal cord. Overexpression of the antiapoptotic protein XIAP in spinal cord neurons inhibited the activation of caspase-12 and reduced caspase-3 and calpain activity. Calpastatin, the regulator of calpain activity, was kept intact in the ALS-XIAP mice. These mice showed a 12% increase in the mean survival suggesting a beneficial effect of XIAP in ALS. The reason for the ultimate cell death of motor neurons in the ALS-XIAP mice may be due to the activation of additional cell death pathways. Thus, we observed that lysosomal proteases particularly, cathepsinB, -D, and -L were activated in the ALS mice spinal cord together with a less marked upregulation of the inhibitors, cystatinB and -C. We also found activation of astrocytes and microglial cells in the spinal cord of ALS mice indicating their involvement in the disease. The results show that both caspase-dependent and -independent pathways are activated during neuronal degeneration in the ALS spinal cord. The results obtained may help to identify novel drug targets for future treatments of ALS.</p>

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an incidence of 1.5-2.7/100000 people/year. Today there is no cure for the disease and only symptomatic treatments are available. ALS progresses rapidly and only 50% of the patients are alive three years after the symptom debut. In ALS, the upper and lower motor neurons undergo degeneration in a process resembling apoptosis. This leads to muscle atrophy and paralysis. The causes of neuronal death are however unknown. In this thesis we have studied transgenic mice carrying human mutant superoxide dismutase, as a model for familial ALS. These mice develop ALS-like symptoms after four months of age with degeneration of the motor neurons. Our results show an involvement of endoplasmic reticulum stress, caspase-12, -9, -3 and procaspase-7 in the ALS mice spinal cord. Overexpression of the antiapoptotic protein XIAP in spinal cord neurons inhibited the activation of caspase-12 and reduced caspase-3 and calpain activity. Calpastatin, the regulator of calpain activity, was kept intact in the ALS-XIAP mice. These mice showed a 12% increase in the mean survival suggesting a beneficial effect of XIAP in ALS. The reason for the ultimate cell death of motor neurons in the ALS-XIAP mice may be due to the activation of additional cell death pathways. Thus, we observed that lysosomal proteases particularly, cathepsinB, -D, and -L were activated in the ALS mice spinal cord together with a less marked upregulation of the inhibitors, cystatinB and -C. We also found activation of astrocytes and microglial cells in the spinal cord of ALS mice indicating their involvement in the disease. The results show that both caspase-dependent and -independent pathways are activated during neuronal degeneration in the ALS spinal cord. The results obtained may help to identify novel drug targets for future treatments of ALS.

A variety of proteases have been shown to promote the progression of cancer by virtue of their ability to degrade extracellular proteinaceous barriers, such as basement membrane and interstitial stroma. At the outset of this study available evidence strongly implicated cathepsin D in breast cancer metastasis. It was envisaged that an antibody inhibitory to the activity of this enzyme might retard invasion, and restrain a tumour from spreading. To this end anti-peptide antibodies were generated against a peptide sequence derived from the substrate capturing "flap" of the enzyme. Inhibition of enzyme activity by these antibodies could not be demonstrated, probably due to the lack of a suitably sensitive enzyme assay. However, the rationale of this study and the expertise gained from it could be applied, in the future, to enzymes that have since been found to be more relevant to tumour invasion. A feature of many transformed cells is an anomalous lysosomal enzyme trafficking system, and concomitant hyper-secretion of some enzymes. The distribution of low pH compartments and lysosomal enzyme-containing compartments was investigated in human breast epithelial cells, and their c-Ha-ras- transformed counterparts. Immunofluorescence and immunoelectron microscopy showed that these compartments have a more peripheral cellular distribution with respect to normal cells, and cathepsins B and D were cell surface-associated. Studies were undertaken to reveal the extracellular matrix degrading ability of c-Ha- ras-transformed cells. Transformed cells exhibited increased degradation of fluorescein-labelled extracellular matrix in serum free medium, and increased motility, and degradation and disruption of extracellular matrix in serum-containing medium. In vitro invasion through artificial basement membrane by transformed cells was investigated using scanning electron microscopy, and was further used to preliminarily identify the proteases involved in invasion by specific inhibition. By this means, greatest inhibition of in vitro invasion was obtained using a specific metalloproteinase inhibitor. Overexpression by transformed cells of a metalloproteinase was detected by gelatin zymography. Together these results suggest that the increased invasive capacity of ras-transformed breast epithelial cells may be largely due to increased metalloproteinase activity. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg , 1996.