A ocorrência de estresses abióticos e bióticos em plantas imaturas de soja, o que inclui a presença de nematoides, podem resultar em morte prematura da planta ou maturação forçada e produzir sementes esverdeadas e de baixo potencial fisiológico. Assim, o objetivo deste trabalho foi avaliar a presença de Meloidogyne javanica e Pratylenchus brachyurus em plantas de soja e a relação com o desenvolvimento da planta, com a ocorrência de sementes esverdeadas e com o potencial fisiológico das sementes. Para isso, foram conduzidos três experimentos. O experimento I foi realizado utilizando plantas da cultivar Pintado, as quais foram submetidas à diferentes tratamentos de inóculo inicial e avaliadas quanto à fenologia e à produtividade e as sementes quanto ao potencial fisiológico. No experimento II foi analisada a resistência de dez cultivares de soja à M. javanica e P. brachyurus. No experimento III foram utilizadas plantas de duas cultivares de soja (TMG-115RR e M 7908 RR, previamente selecionados no experimento II), dois tratamentos de população de nematoides (0 e 7000 nematoides) e dois tratamentos de estresse hídrico (com e sem), cujas plantas foram avaliadas quanto a fenologia e produção de vagens e sementes, as raízes quanto à multiplicação de nematoides e as sementes quanto as determinações do grau de umidade, do potencial fisiológico (testes de germinação, tetrazólio, envelhecimento acelerado, condutividade elétrica, emergência de plântulas em areia e análise computadorizada de imagens de plântulas), ocorrência de sementes esverdeadas (método visual e fluorescência de clorofila) e citometria de fluxo. Com os resultados do experimento I, observou-se que a presença de M. javanica e de P. brachyurus em plantas de soja, independentemente da população inicial, provoca a redução do ciclo da planta devido exclusivamente à diminuição do estádio de senescência destas, porém a qualidade de sementes não foi afetada com população inicial de nematoides mais elevada (2400 espécimes). Todas as cultivares testadas no experimento II foram classificadas como suscetíveis, porém a cultivar TMG-115RR e M 7908 RR foram escolhidas para a condução do experimento III por permitirem boa reprodução dos nematoides em estudo e por serem consideradas por algumas empresas produtoras de sementes com sendo sensíveis a ocorrência de sementes esverdeadas. Finalmente, com os resultados do experimento III verificou-se que a população inicial de 7000 nematoides afeta, negativamente, a produção, a ocorrência de sementes esverdeadas e a qualidade de sementes. Entretanto, a intensidade do efeito de M. javanica e de P. brachyurus no desenvolvimento de plantas de soja, na ocorrência de sementes esverdeadas e no seu potencial fisiológico depende da população inicial e da espécie do nematoide, da cultivar e das condições ambientais as quais as plantas são submetidas. / Abiotic and biotic stresses in immature soybean plants, including nematodes presence, can result in premature plant death and can produce green seeds with low physiological potential. The aim of this study was to evaluate the Meloidogyne javanica and Pratylenchus brachyurus presence on soybean plants and the relationship with plant development, the green seeds occurrence and the seed physiological potential. For this, three experiments were done. The experiment I was carried out using the cultivar Pintado, which was inoculated with different nematode population and the phenology, productivity, and the seed physiological potential were evaluated. In experiment II it was analyzed the resistance of ten soybean cultivars to M. javanica and P. Brachyurus. In experiment III plants of two soybean cultivars (TMG-115RR and M 7908 RR, chosen by experiment II) were submitted to two nematode population treatments (0 nematodes and 7000) and two levels of water stress (with and without) and they were evaluated as phenology and production of pods and seeds, the multiplication of nematodes on roots and the determinations of moisture content, physiological potential (germination, tetrazolium, accelerated aging, electrical conductivity, sand seedling emergence and seedling computerized image analysis), the occurrence of green seeds (visual method and chlorophyll fluorescence) and flow cytometry on seeds. It was observed in the results of experiment I that the M. javanica and P. brachyurus on soybean plants, regardless of the initial population, decreases of cycle plant due the decrease on senescence phase, however, the seed quality was unaffected with higher initial nematode population (2400 nematodes). All the cultivars in experiment II were classified as susceptible, but the cultivar TMG-115RR and M 7908 RR were chosen for the experiment III because they allowed a good nematode reproduction and because some seed companies considered them as sensible to soybean green seed occurrence. Finally, the results of experiment III showed that the initial population of 7000 nematodes affected negatively the production, the soybean green seeds occurrence and the seed quality. However, the effect of M. javanica and P. brachyurus in the soybean plantas development, in the soybean green seeds occurrence and their physiological potential depends on the initial nematode population and species, cultivar and environmental conditions which the plants are exposed.

Neste estudo foram avaliados os efeitos farmacológicos do vemurafenibe (inibidor BRAFV600E) e da cloroquina (inibidor de autofagia) na viabilidade celular e crescimento tumoral das sublinhagens de melanoma:G361 pLKO que expressa dermicidina e G361 IBC I com silenciamento da expressão. As células G-361 responderam a vemurafenibe (2 μM) e cloroquina (100 μM), isoladamente ou combinadas, com aumento apoptose, e redução das taxas de senescência. Vemurafenibe (50 mg/kg / 21 dias) inibiu o crescimento tumoral em camundongos imunodeficientes independente da expressão da DCD. A combinação com Cloroquina (30 mg/kg) a cada 24 horas, acelerou, enquanto a cada 72 horas, reduziu o crescimento tumoral. Os tumores apresentaram alterações morfológicas e núcleos atípicos; e não expressaram os marcadores S100, HMB-45, Mela-A ou citoqueratinas. Este trabalho confirmar a eficácia do vemurafenibe e sugere o potencial adjuvante da cloroquina no tratamento de melanomas. O estudo também confirma o papel da dermcidina como oncogne e fator de crescimento de células de melanoma maligno. / In this study we evaluated the pharmacological effects of vemurafenib ( inhibitor BRAFV600E) and chloroquine (autophagy inhibitor) in cell viability and tumor growth of two melanoma cell lines identified as G-361 pLKO, which expresses dermcidin, and G361 IBC I which silenced DCD expression. G-361 melanoma cells responded to vemurafenib (1-2 μM) and chloroquine (50-100 μM) alone or combined, with increased apoptosis rates, while decreasing senescent cells. Vemurafenib (50 mg/kg / 21 days) inhibited melanoma growth in immunodeficient mice independent of dermicidin. Chloroquine (30 mg/kg) in combination with vemurafenib, accelerated (at 24 hour interval), and reduced (at 72 hours interval), melanoma growth. Tumor tissues showed atypical cell morphology and nuclear histological patterns and melanocytic differentiation biomarkers S100, HMB-45, Melan-A or pancytokeratins were not. This work confirms the efficacy of vemurafenib and suggests potential adjuvant effect of chloroquine. It also confirms the role of dermcidin as growth factor and oncogene for melanoma cells.

O presente estudo teve como objetivos comparar o sêmen de cães jovens e senis, por avaliação morfo-funcional, estresse oxidativo e quantificação de produtos avançados de glicação (AGEs); comparar a congelabilidade seminal de cães jovens e senis e verificar a ação dos produtos avançados de glicação, oxidação proteica e estresse oxidativo na criopreservação seminal de cães senis. Foram selecionados 22 cães, alocados em dois grupos experimentais de acordo com a idade: Grupo Jovem (n=11) e Grupo Senil (n=11). Os grupos foram adicionalmente subdivididos em Grupo Sêmen Fresco e Grupo Sêmen Criopreservado. A divisão etária foi realizada de acordo com o porte dos animais, sendo porte pequeno considerado senil a partir de 8 anos de idade, porte médio a partir de 7 anos de idade e porte grande acima de 6 anos de idade. Independentemente do porte, os cães jovens em idade reprodutiva foram considerados entre 1 e 5 anos de idade. O Grupo Fresco foi submetido a avaliações seminais imediatas, incluindo volume, cor, aspecto do ejaculado, concentração espermática e análise computadorizada da motilidade (CASA). Logo após, foram realizadas avaliações morfo-funcionais, incluindo atividade mitocondrial dos espermatozoides, estresse oxidativo lipídico, estresse oxidativo proteico, dosagem de produtos avançados de glicação e dosagem de concentração proteica, citometria de fluxo utilizando as sondas fluorescentes para a avaliação espermática da integridade de membrana plasmática e acrossomal e de potencial de membrana mitocondrial e análise de fragmentação de DNA. O Grupo Congelado foi submetido ao protocolo de congelação em uma etapa e após, no mínimo uma semana, as amostras foram descongeladas a 37ºC por 30 segundos e, então, avaliadas quanto à concentração espermática, análise computadorizada da motilidade (CASA) e as mesmas avaliações morfo-funcionais realizadas para o Grupo Jovem. Como resultados, os machos do Grupo Jovem apresentaram maior escore de libido, parâmetros da motilidade espermática, alta atividade mitocondrial dos espermatozoides e menores valores de atividade mitocondrial média, defeitos espermáticos totais, defeitos espermáticos maiores e gota citoplasmática proximal. No sêmen fresco, o Grupo Jovem obteve maiores valores de integridade da membrana acrossomal dos espermatozoides e baixo potencial de membrana mitocondrial, assim como menores valores de integridade da membrana plasmática e acrossomal e alto potencial de membrana mitocondrial. No sêmen descongelado, o Grupo Jovem apresentou maiores valores de integridade de membrana acrossomal dos espermatozoides. No sêmen de cães jovens, o Sub-grupo Fresco obteve maiores valores de integridade de membrana acrossomal e integridade de membrana acrossomal com lesão de membrana plasmática. No sêmen de cães senis, o Sub-grupo Fresco apresentou maiores valores de integridade de membrana acrossomal, integridade de membrana plasmática e acrossomal e alto potencial de membrana mitocondrial, assim como menor porcentagem de espermatozoides com baixo potencial de membrana mitocondrial. Na comparação entre os sub-grupos, houve maiores valores para parâmetros da motilidade espermática, integridade de membrana plasmática com lesão de acrossomo, médio potencial de membrana mitocondrial, integridade de membrana plasmática, alta atividade mitocondrial e estresse oxidativo no Sub-grupo Descongelado, além de maiores valores de amplitude de deslocamento lateral da cabeça, espermatozoides estáticos, lesão de membrana acrossomal e plasmática, média atividade mitocondrial e concentração de proteínas no pellet de espermatozoides. A partir de tais resultados, é possível concluir que o sêmen de cães senis apresenta qualidade inferior ao de cães jovens, bem como reduzida congelabilidade. Nos cães senis, possivelmente, a falha na eliminação da gota citoplasmática dos espermatozoides promova disfunções mitocondriais, culminando na alteração da motilidade espermática. Por fim, as avaliações de parâmetros oxidativos não se mostram acuradas para a avaliação do impacto da senescência reprodutiva. / This study aimed to compare the semen of young and senile dogs, through the evaluation of morphological and functional attributes, oxidative stress and quantification of advanced glycation ending products (AGEs); compare the seminal freezability of young and senile dogs and evaluate the effects of advanced glycation ending products, oxidation protein and oxidative stress on seminal cryopreservation of senile dogs. Twenty two dogs were selected and allocated into two experimental groups according to their age: Young Group (n=11) and Senile Group (n=11). These groups were additionally divided into Fresh Semen Group and Frozen Semen Group. Age distribution was performed according to the size of the animals, being small animals considered senile from 8 years of age onwards, medium size from 7 years old and large size over 6 years old. Regardless of the body size, dogs were considered young if they were at reproductive maturity from 1 to 5 years old. The Fresh Group was subjected to immediate seminal assessments, including volume, color, aspect of the ejaculate, sperm concentration and computer analysis of sperm motility (CASA). Then morpho-functional assessments were carried out, including sperm mitochondrial activity, lipid oxidative stress, protein oxidative stress, dosage of advanced glycation ending products and of protein concentration, flow cytometry using fluorescent probes to evaluate plasmatic and acrosomal membrane integrity and mitochondrial membrane potential and DNA fragmentation analysis. The semen from the Frozen Group was submitted to one step freezing protocol and samples were thawed after not less than 1 week at 37°C for 30 seconds and evaluated for sperm concentration, motility computerized analysis (CASA) and same the morpho-functional analysis performed for the Young Group. Male dogs from the Young Group presented higher libido score, parameters of sperm motility, percentage of sperm with high mitochondrial activity and lower percentage of sperm of medium mitochondrial activity, total spermatic defects, major spermatic defects and proximal cytoplasmic droplet. For the fresh semen of the Young Group, higher values of acrosomal membrane integrity and low mitochondrial membrane potential, as well as lower values of plasma and acrosomal membrane integrity and high mitochondrial membrane potential were noticed. In the post-thaw semen, the Young Group showed higher values of spermatic acrosomal membrane integrity. For the semen of young dogs, the Fresh Group had higher values of acrosomal membrane integrity and acrosomal membrane integrity with plasma membrane damage. In the semen of senile dogs, the Fresh Group presented higher values of acrosomal membrane integrity, plasma and acrosomal membrane integrity and high mitochondrial membrane potential, as well as lower percentage of sperm with low mitochondrial membrane potential. Comparing sub-groups, higher values for sperm motility parameters, plasma membrane integrity with acrosome injury, medium mitochondrial membrane potential, plasmatic membrane integrity, high mitochondrial activity and oxidative stress was noticed for the Thawed group, as well as greater values of lateral displacement amplitude of the sperm head, static spermatozoa, acrosomal and plasmatic membrane lesions, medium mitochondrial activity and protein concentration in the spermatozoa pellet. Based on the present results, it is possible to conclude that the semen of senile dogs presents inferior quality compared to young dogs, as well as less freezability. The possible failure to eliminate the sperm cytoplasmic droplet in senile dogs sperm promotes mitochondrial dysfunctions, culminating to alterations on sperm motility. Finally, the evaluation of oxidative parameters is not feasible for the impact evaluation of reproductive senescence.

A base evolucionaria da senescência é um problema biológico de longa data. Senescência, no sentido da deterioração progressiva de um organismo, distingue-se de envelhecimento, ou a mera passagem do tempo. Como, pelo menos em mamíferos, senescência e envelhecimento ocorrem simultaneamente, os termos são tomados erroneamente como sinônimos. A senescência parece explicada pelo desgaste do organismo, levando a um paradoxo frente aos mecanismos de seleção natural, pois, sendo a maquinaria biológica portadora de mecanismos de auto-reparo, esperáramos o aprimoramento destes, com gradual eliminação da deterioração associada ao envelhecimento. Historicamente, procurou-se resolver este paradoxo imaginando-se que a senescência conferisse uma vantagem adaptativa, mas este argumento, que requereria distinguir os indivíduos mais velhos, é circular. A partir de meados do século XX, três hipóteses prevaleceram. O acúmulo de mutações, proposto por Medawar (1951), considera que o decaimento gradual da força de seleção com a idade favorece o acúmulo de genes deletérios expressos em idades avançadas. O antagonismo pleiotrópico, proposto por Williams (1957), defende que genes ligados a características benéficas e deletérias poderiam ser, em certas condições, favoravelmente selecionados. Finalmente, a teoria da soma descartável, proposta por Kirkwood (1975), sugere que organismos são favoravelmente selecionados quando investem em Reprodução mesmo em detrimento da manutenção somática. A descrição dinâmica dos fenômenos envolvidos em cada hipótese e a contribuição relativa de cada uma é, ainda, objeto de debate. O presente trabalho visa ao desenvolvimento de modelos computacionais estocásticos que mimetizem as condição para cada uma delas. Iniciamos o desenvolvimento pela ordem histórica, testando o mecanismo proposto por Medawar, que é o objeto desta tese. A teoria do acúmulo de mutações encontrou críticos que sugerem que este mecanismo levaria os efeitos deletérios à sincronia em idades muito avançadas, tornando a senescência um fenômeno repentino e limitado a tais idades. Isto contrariaria a observação experimental, pois a senescência é um processo gradual e mesmo animais silvestres exibem fenômenos senescentes detectáveis precocemente. Para manter a modelagem compatível com o conhecimento atual sobre genética de populações, incluímos neste modelo os efeitos da seleção, da deriva genética e de diferentes taxas de mutação. Como previsto, em nossas simulações a moda das idades de manifestação dos genes deletérios se estabilizou apenas em idades muito avançadas, próximas ao término das distribuições etárias. Também como esperado, estas distribuições terminaram em idades mais precoces nos cenários de maior mortalidade extrínseca. No entanto, em todas as nossas simulações, houve distribuição mais ou menos larga das idades de manifestação em torno da moda. A distribuição alargou-se com o aumento da probabilidade de mutação, sugerindo que as idades de manifestação podem espalhar-se ao longo da vida, chegando, em alguns cenários, à manutenção de alelos com manifestação ao nascer. Isto é compatível com o modelo de alelos ineptos utilizado em genética populacional, em que diferentes variantes concorrem até atingirem um equilíbrio entre seleção, mutação e deriva genética. Considerando-se o critério demográfico para senescência, em que a mortalidade aumenta em função da idade, podemos dizer que as nossas simulações evoluíram populações senescentes. Embora nossos dados não contrariem as outras teorias da senescência, claramente mostram que a perda da força de seleção não é um mecanismo suficiente para a senescência. Especialmente com alelos de expressão tardia, as forças de deriva podem ser preponderantes e devem ser levadas em conta para explicar a evolução da senescência / The evolutionary basis of senescence is a long standing biological problem. Senescence, in the sense of progressive deterioration of an organism, is distinguished from aging, or the mere passage of time. Because, at least in mammals, aging and senescence occur simultaneously, the terms are wrongly taken as synonyms. Senescence seems explained by the wear of the organism, leading to a paradox facing the mechanisms of natural selection, because, being the biological machinery bearer of self-repair mechanisms, we would expect their improvement, with gradual elimination of the deterioration associated with aging. Historically, there were attempts to resolve this paradox by supposing that senescence confers an adaptive advantage, but this argument would require that older individuals were previously distinct from younger ones and is, therefore, circular. From mid-twentieth century, three hypotheses have prevailed. The mutation accumulation, proposed by Medawar (1951), proposes that the gradual decay of the force of selection with age favors the accumulation of deleterious genes expressed in advanced ages. The antagonistic pleiotropy, proposed by Williams (1957), argues that genes linked to benecial and deleterious traits could, under certain conditions, be favorably selected. Finally, the disposable soma theory, proposed by Kirkwood (1975), suggests that organisms are positively selected when they invest in reproduction even at the expense of somatic maintenance. The dynamic description of the phenomena involved in each mechanism and the relative contribution of each one is still debated. The present work aims to develop stochastic computer models that mimic the conditions for each. We started by historical order, testing the mechanism proposed by Medawar, which is the subject of this thesis. The theory of mutation accumulation found critics who suggest that this mechanism would cause deleterious eects to synchronize in very advanced ages, causing senescence to be a sudden phenomenon limited to these ages. This is a contradiction with the experimental observation, because senescence is a gradual process and even wild animals exhibit senescent phenomena detectable in young ages. To keep the model consistent with the current knowledge on population genetics, this model included the eects of selection, genetic drift and dierent mutation rates. As predicted, in our simulations the mode of the age of onset of deleterious genes stabilized only in very advanced ages, near the end of the age distribution. Also as expected, these distributions ended in earlier ages in scenarios of higher extrinsic mortality. However, in all our simulations, there was more or less wide distribution of ages of onset around the mode. The distribution is enlarged with increased probabilities of mutation, suggesting that the ages of onset may spread throughout life, including, in some scenarios, the maintenance of alleles with manifestation at birth. This is consistent with the innite alleles\' model used in population genetics, where dierent variants compete until achieving an equilibrium between selection, mutation and genetic drift. Considering the demographic criterion for senescence, in which mortality increases with age, we can say that our simulations evolved senescent populations. Although our data do not con ict with the other theories of senescence, they clearly show that the falling force of selection with age is not a sucient mechanism for senescence. Especially with alleles of late expression, the forces of genetic drift may be prominent and should be taken into account to explain the evolution of senescence

O telômero é uma sequência repetitiva da dupla cadeia do DNA que protege as pontas dos cromossomos. Seu comprimento é mantido pela telomerase, cuja expressão ocorre em células de câncer, mas não em células somáticas. A célula apresenta um número definido de divisões antes do telômero sofrer erosão. A quebra do DNA ativa a p53, supressor tumoral que induz senescência e respostas de pontos de checagem. O desenvolvimento de inibidores de telomerase tem importância clínica para o câncer. Estudamos os efeitos dos inibidores de telomerase. Duas linhagens celulares LC-HK2 (NSCLC) e hTERT RPE-1 foram tratadas com os inibidores TMPyP4 (5µM) e Thymoquinone (10 e 40 µM) durante 72 e 120 h. TMPyP4 aumentou a porcentagem de células com dano na membrana, induziu mudança na morfologia da célula e diminuiu a expressão do mRNA da vimentina e vinculina. Thymoquinone aumentou a frequência de células senescentes, células com dano na membrana e induziu morte celular. Ambos os inibidores diminuíram a atividade da telomerase, afetando a proliferação e induzindo morte celular. / The telomere is a repetitive double-strand sequence of DNA that protects the chromosomes ends. Its length is maintained by telomerase, whose expression occurs in cancer cells, but not in somatic cells. The cell has a defined number of divisions before the telomere undergoes erosion. DNA break activates p53, tumor suppressor and induces senescence and checkpoint responses. The development of telomerase inhibitors is of clinical importance for cancer. We studied the effects of telomerase inhibitors. Two cell lines LC-HK2 (NSCLC) and hTERT RPE-1 were treated with inhibitors TMPyP4 (5 M) and Thymoquinone (10 and 40 M) for 72 and 120 h. TMPyP4 increased the percentage of cells with membrane damage, induced change in cell morphology, and decreased mRNA expression of vimentin and vinculin. Thymoquinone increased the frequency of senescent cells, cells with membrane damage and induced cell death. Both inhibitors decreased telomerase activity, affecting proliferation and inducing cell death.

O presente estudo teve como objetivos comparar o sêmen de cães jovens e senis, por avaliação morfo-funcional, estresse oxidativo e quantificação de produtos avançados de glicação (AGEs); comparar a congelabilidade seminal de cães jovens e senis e verificar a ação dos produtos avançados de glicação, oxidação proteica e estresse oxidativo na criopreservação seminal de cães senis. Foram selecionados 22 cães, alocados em dois grupos experimentais de acordo com a idade: Grupo Jovem (n=11) e Grupo Senil (n=11). Os grupos foram adicionalmente subdivididos em Grupo Sêmen Fresco e Grupo Sêmen Criopreservado. A divisão etária foi realizada de acordo com o porte dos animais, sendo porte pequeno considerado senil a partir de 8 anos de idade, porte médio a partir de 7 anos de idade e porte grande acima de 6 anos de idade. Independentemente do porte, os cães jovens em idade reprodutiva foram considerados entre 1 e 5 anos de idade. O Grupo Fresco foi submetido a avaliações seminais imediatas, incluindo volume, cor, aspecto do ejaculado, concentração espermática e análise computadorizada da motilidade (CASA). Logo após, foram realizadas avaliações morfo-funcionais, incluindo atividade mitocondrial dos espermatozoides, estresse oxidativo lipídico, estresse oxidativo proteico, dosagem de produtos avançados de glicação e dosagem de concentração proteica, citometria de fluxo utilizando as sondas fluorescentes para a avaliação espermática da integridade de membrana plasmática e acrossomal e de potencial de membrana mitocondrial e análise de fragmentação de DNA. O Grupo Congelado foi submetido ao protocolo de congelação em uma etapa e após, no mínimo uma semana, as amostras foram descongeladas a 37ºC por 30 segundos e, então, avaliadas quanto à concentração espermática, análise computadorizada da motilidade (CASA) e as mesmas avaliações morfo-funcionais realizadas para o Grupo Jovem. Como resultados, os machos do Grupo Jovem apresentaram maior escore de libido, parâmetros da motilidade espermática, alta atividade mitocondrial dos espermatozoides e menores valores de atividade mitocondrial média, defeitos espermáticos totais, defeitos espermáticos maiores e gota citoplasmática proximal. No sêmen fresco, o Grupo Jovem obteve maiores valores de integridade da membrana acrossomal dos espermatozoides e baixo potencial de membrana mitocondrial, assim como menores valores de integridade da membrana plasmática e acrossomal e alto potencial de membrana mitocondrial. No sêmen descongelado, o Grupo Jovem apresentou maiores valores de integridade de membrana acrossomal dos espermatozoides. No sêmen de cães jovens, o Sub-grupo Fresco obteve maiores valores de integridade de membrana acrossomal e integridade de membrana acrossomal com lesão de membrana plasmática. No sêmen de cães senis, o Sub-grupo Fresco apresentou maiores valores de integridade de membrana acrossomal, integridade de membrana plasmática e acrossomal e alto potencial de membrana mitocondrial, assim como menor porcentagem de espermatozoides com baixo potencial de membrana mitocondrial. Na comparação entre os sub-grupos, houve maiores valores para parâmetros da motilidade espermática, integridade de membrana plasmática com lesão de acrossomo, médio potencial de membrana mitocondrial, integridade de membrana plasmática, alta atividade mitocondrial e estresse oxidativo no Sub-grupo Descongelado, além de maiores valores de amplitude de deslocamento lateral da cabeça, espermatozoides estáticos, lesão de membrana acrossomal e plasmática, média atividade mitocondrial e concentração de proteínas no pellet de espermatozoides. A partir de tais resultados, é possível concluir que o sêmen de cães senis apresenta qualidade inferior ao de cães jovens, bem como reduzida congelabilidade. Nos cães senis, possivelmente, a falha na eliminação da gota citoplasmática dos espermatozoides promova disfunções mitocondriais, culminando na alteração da motilidade espermática. Por fim, as avaliações de parâmetros oxidativos não se mostram acuradas para a avaliação do impacto da senescência reprodutiva. / This study aimed to compare the semen of young and senile dogs, through the evaluation of morphological and functional attributes, oxidative stress and quantification of advanced glycation ending products (AGEs); compare the seminal freezability of young and senile dogs and evaluate the effects of advanced glycation ending products, oxidation protein and oxidative stress on seminal cryopreservation of senile dogs. Twenty two dogs were selected and allocated into two experimental groups according to their age: Young Group (n=11) and Senile Group (n=11). These groups were additionally divided into Fresh Semen Group and Frozen Semen Group. Age distribution was performed according to the size of the animals, being small animals considered senile from 8 years of age onwards, medium size from 7 years old and large size over 6 years old. Regardless of the body size, dogs were considered young if they were at reproductive maturity from 1 to 5 years old. The Fresh Group was subjected to immediate seminal assessments, including volume, color, aspect of the ejaculate, sperm concentration and computer analysis of sperm motility (CASA). Then morpho-functional assessments were carried out, including sperm mitochondrial activity, lipid oxidative stress, protein oxidative stress, dosage of advanced glycation ending products and of protein concentration, flow cytometry using fluorescent probes to evaluate plasmatic and acrosomal membrane integrity and mitochondrial membrane potential and DNA fragmentation analysis. The semen from the Frozen Group was submitted to one step freezing protocol and samples were thawed after not less than 1 week at 37°C for 30 seconds and evaluated for sperm concentration, motility computerized analysis (CASA) and same the morpho-functional analysis performed for the Young Group. Male dogs from the Young Group presented higher libido score, parameters of sperm motility, percentage of sperm with high mitochondrial activity and lower percentage of sperm of medium mitochondrial activity, total spermatic defects, major spermatic defects and proximal cytoplasmic droplet. For the fresh semen of the Young Group, higher values of acrosomal membrane integrity and low mitochondrial membrane potential, as well as lower values of plasma and acrosomal membrane integrity and high mitochondrial membrane potential were noticed. In the post-thaw semen, the Young Group showed higher values of spermatic acrosomal membrane integrity. For the semen of young dogs, the Fresh Group had higher values of acrosomal membrane integrity and acrosomal membrane integrity with plasma membrane damage. In the semen of senile dogs, the Fresh Group presented higher values of acrosomal membrane integrity, plasma and acrosomal membrane integrity and high mitochondrial membrane potential, as well as lower percentage of sperm with low mitochondrial membrane potential. Comparing sub-groups, higher values for sperm motility parameters, plasma membrane integrity with acrosome injury, medium mitochondrial membrane potential, plasmatic membrane integrity, high mitochondrial activity and oxidative stress was noticed for the Thawed group, as well as greater values of lateral displacement amplitude of the sperm head, static spermatozoa, acrosomal and plasmatic membrane lesions, medium mitochondrial activity and protein concentration in the spermatozoa pellet. Based on the present results, it is possible to conclude that the semen of senile dogs presents inferior quality compared to young dogs, as well as less freezability. The possible failure to eliminate the sperm cytoplasmic droplet in senile dogs sperm promotes mitochondrial dysfunctions, culminating to alterations on sperm motility. Finally, the evaluation of oxidative parameters is not feasible for the impact evaluation of reproductive senescence.

As the so-called “Mothership of the Human Genome,” the cell nucleus must keep all vital genetic information safe, but accessible, inside a strong protective envelope. The inner membrane of the nuclear envelope is lined by tough but adaptable proteins called lamins. While lamins polymerize into fibrous structures that hold up the “walls” of the nucleus, they also serve as an internal scaffold for the complex machinery involved in DNA replication and gene expression. It is in this later role that we have been looking for clues to premature and possibly to normal aging. One type of lamins, Lamin A is made through an unusual pathway involving a lipid dependent cleavage of a larger precursor called prelamin A. The functional significance of this processing pathway is that prelamin A cannot assemble and is inhibitory of proper lamina formation. Pathological cases of immature lamin A accumulation include Hutchinson-Gilford progeria syndrome (HGPS) or Progeria characterized by premature aging and Restrictive Dermopathy (RD), a lethal prenatal disease. We have previously shown that accumulation of prelamin A leads to cell cycle arrest and drastic changes in expression of genes involved in cell cycle control, among those, several members of the FoxO family of transcription factors. The goal of this study was to determine the mechanisms by which accumulation of uncleavable prelamin A activates FoxO-mediated cell cycle arrest. Cells expressing an uncleavable form of Lamin A in an inducible manner were used to determine subcellular distribution of FoxO3a upon accumulation of prelamin A. This was done by indirect immunofluorescence and Western blotting. The proliferation rate of these cells and controls expressing wild type Lamin A was also determined by measuring the incorporation of BrdU into DNA. During these experiments, it was hypothesized and observed that overexpression of prelamin A leads to redistribution of FoxO3a from the cytoplasm of the cell to the nucleoplasm. Expression of FoxO3a target genes was accordingly increased, leading to a decrease in cell proliferation. The information obtained from this study could not only be of interest in broadening our knowledge of the mechanisms of quiescence and aging in general, but also could inform the discussion of the use of several therapeutics for the treatment of Progeria and other diseases that result from the accumulation of prelamin A.

Le vieillissement de l'organisme prédispose à de nombreuses pathologies chroniques telles que l'insuffisance cardiaque (IC). Des études récentes ont montré que l'accumulation de cellules sénescentes dans les organes au cours du vieillissement est associée à l'apparition de ces pathologies. La sénescence cellulaire a initialement été décrite comme un arrêt stable du cycle cellulaire permettant de limiter la prolifération des cellules dont l'ADN est endommagé. Ce processus s'accompagne de profondes modifications de la fonction cellulaire, avec notamment l'acquisition d'un phénotype sécrétoire associé à la sénescence. La sénescence peut être induite par un raccourcissement des télomères ou par l'exposition à des signaux de stress, tels que le stress oxydant ou l'irradiation, qui entrainent l'activation de la réponse cellulaire aux dommages de l'ADN et l'expression des gènes suppresseurs de tumeurs (p16INK4a, p21CIP1, p53). Ces inhibiteurs du cycle cellulaire sont classiquement utilisés comme marqueur de sénescence car leur expression augmente de manière ubiquitaire au cours du vieillissement. Toutefois, ces marqueurs ne sont pas spécifiques du tissu concerné et un des objectifs de ma thèse a été d'identifier de nouveaux marqueurs de sénescence tissu-spécifiques qui pourraient caractériser un vieillissement cardiaque pathologique. Le vieillissement cardiaque se caractérise par une hypertrophie des cardiomyocytes, une sensibilité accrue au stress et une prédisposition à l'IC. Les cardiomyocytes étant des cellules post-mitotiques, les mécanismes de sénescence mis en jeu, les marqueurs associés et leur rôle potentiel dans l'IC demeurent à l'heure actuelle peu caractérisés. Au cours de ce travail de thèse nous avons donc entrepris : 1) d'étudier le rôle des télomères et des dysfonctions mitochondriales dans l'induction de la sénescence du cardiomyocyte et 2) d'identifier des marqueurs spécifiques. Nous avons tout d'abord montré que les cardiomyocytes de souris âgées expriment les marqueurs classiques de la sénescence comme p16INK4a, p53 et p21CIP1. Concernant les mécanismes inducteurs, nous avons étudié l'implication des dommages télomériques (telomere associated foci, TAF). Au cours du vieillissement, nous avons observé une augmentation du nombre de TAFs par cardiomyocytes en association avec l'hypertrophie. De plus, l'induction de TAFs in vitro est suffisante à l'activation de la voie de sénescence p53/p21CIP1 et l'hypertrophie dans une lignée de cardiomyoblastes H9c2. La formation des TAFs est augmentée chez des souris avec une dysfonction mitochondriale et est associée à l'activation des voies p53/p21CIP1. Par ailleurs, les cardiomyocytes âgés présentent une dérégulation des gènes impliqués dans la biologie mitochondriale pouvant rendre compte de l'augmentation des TAFs. Par l'analyse haut débit du transcriptome (RNAseq) nous avons identifié six nouveaux gènes qui sont surexprimés dans les cardiomyocytes sénescents (Prom2, Kcnk1, Pah, Edn3, Gdf15, Tgfb2). La comparaison d'expression de ces gènes dans le cœur avec d'autres tissus et avec le stroma cardiaque lors vieillissement a permis de confirmer la spécificité d'expression de ces marqueurs au niveau des cardiomyocytes. Nous avons validé cette signature dans deux modèles in vitro de sénescence induite par le stress et démontré que l'expression de certains de ces marqueurs est dépendante de la voie p53. De plus, l'expression de Prom2 est associée à l'hypertrophie des cardiomyocytes. En conclusion, nous avons démontré, qu'avec le vieillissement, les cardiomyocytes présentent un programme de sénescence associé à une dysfonction mitochondriale et une augmentation des TAFs. Cette sénescence se caractérise par l'activation des voies classiques de sénescence (p16INK4, p53/p21CIP1), une hypertrophie et l'acquisition d'une signature spécifique. Ces marqueurs offrent de nouvelles perspectives dans la compréhension de la sénescence cardiaque et dans son implication potentielle dans l'IC. / Ageing of the organism is associated with several chronic pathologies such as heart failure (HF). Recent studies have demonstrated the link between the accumulation of senescent cells during ageing and age-associated diseases. Cellular senescence, originally defined as a stable cell cycle arrest, acts as a tumorigenic repressor by limiting the proliferation of DNA damaged cells. Despite this protective effect, senescence is characterized by deep remodeling of cell biology which drives functional disorders, such as the acquisition of a senescence-associated secretory phenotype (SASP). Senescence can be induced by telomeric attrition and by exposition to cellular stress signals such as oxidative stress or irradiation, which induce telomeric damage, activation of the DNA Damage Response (DDR) and increased expression of antitumoral genes (p16INK4a, p21CIP1, p53). These genes are classically used as markers of senescence because their expression increases in several tissues during ageing but they are not tissue-specific. Therefore, At the cardiac level, ageing is characterized by cardiomyocytes hypertrophy, increased sensitivity to stress and highest risk of developing HF. Cardiomyocytes are post- mitotic cells and the senescence inductor mechanisms, specifics markers and their role in HF remains poorly understood. This thesis project is articulated around two aims, 1/ studying the role of telomeric damages and mitochondrial dysfunction in triggering cardiomyocyte senescence and 2/ identification of specifics markers. Fisrtly, we shown that aged cardiomyocytes overexpress classic markers of senescence such as p16INK4a, p53 et p21CIP1. Concerning the inductors mechanisms, we studied the implication of telomeric damages (telomere associated foci, TAF). During ageing, we found an increased number of TAFs per cardiomyocytes and their association with hypertrophy. Moreover, TAF- induction in cardiac H9c2 in vitro activated the p53/p21 pathway and induced senescence. These data confirmed the role of TAFs in cardiomyocyte senescence induction. Furthermore, aged cardiomyocytes exhibit a global alteration of genes involved in mitochondrial biology, oxidative stress and metabolism in aged cardiomyocytes that could play a prominent role in TAF accumulation with ageing. In a second part of the study, by using a next generation sequencing method (RNA-seq) we identified 6 new genes highly expressed in senescent cardiomyocytes (Prom2, Kcnk1, Pah, Edn3, Gdf15 and Tgfb2). Expression comparison with other senescent organs and cardiac stromal cells confirmed these new genes as cardiomyocyte specific. Thanks to an in vitro approach, we validate this signature by using different models of stress-induced senescence in cardiac H9c2 cells and demonstrated the implication of the p53 in the regulation of some of these genes. Moreover, Prom2 expression is associated with cardiomyocytes hypertrophy. In conclusion, we demonstrated that, with ageing, cardiomyocytes display a senescence phenotype associated with mitochondrial dysfunction and TAFs. This process is characterized by classic markers (p16INK4, p53/p21CIP1), hypertrophy and new identified signature. These new markers offer innovative perspectives in the understanding and the identification of the cardiac senescence and their potential deleterious role in heart failure.

Le vieillissement est associé un mécanisme d'arrêt du cycle cellulaire nommé senescence. Au niveau de l'adipocyte, cet état cellulaire semble contribuer à la survenue d'altérations métaboliques et à un état pro-inflammatoire. Dans ce contexte, le tissu adipeux blanc viscéral pourrait jouer un rôle déterminant sur la perte du contrôle métabolique et ainsi participer à l'installation de pathologies associées au vieillissement. Au cours du vieillissement, le tissu adipeux blanc subit des modifications morphologiques et physiologiques conduisant à une altération progressive des fonctions de stockage et endocrines de l'adipocyte. Ainsi, un nouveau profil sécrétoire pro-inflammatoire appelé SASP (Senescence Associated Secretory Phenotype) a pu être mis en évidence et pourrait être impliqué dans la survenue de différentes pathologies liées à l'âge (diabète, insuffisance cardiaque ou rénales, ...). Dans ce sens, l'analyse précise du SASP d'adipocytes issus de souris de différents âges nous a permis d'identifier une cytokine pro-inflammatoire, l'haptoglobine, comme un nouveau candidat potentiellement impliqué dans les désordres métaboliques et inflammatoires associés au vieillissement. Nos premiers résultats montrent que, via une boucle de régulation, la senescence augmente la production d'haptoglobine adipocytaire et que réciproquement., cette production entretien la senescence de l'adipocyte Au niveau fonctionnel, l'haptoglobine altère les principales fonctions adipocytaires métaboliques telles que la lipolyse et la sensibilité à l'insuline. Des expériences sont en cours afin de confirmer in vivo l'importance de cette adipocytokine sur les altérations métaboliques entrainant une accélération du vieillissement de l'organisme. Cette étude permettra de mieux comprendre la participation de l'haptoglobine dans la perte des fonctions du tissu adipeux afin de développer de nouvelles stratégies thérapeutiques pour ralentir les processus de vieillissement. / Aging is associated with a cell cycle arrest mechanism named senescence. In adipocyte, this cell state could contribute to metabolic alterations as well as a low-grade inflammatory state. In this context, visceral white adipose tissue could play a major role in age-associated setup pathologies through the loss of metabolic control. Indeed, during aging, white adipose tissue undergoes functional and morphological modifications progressively leading to altered storage and endocrine capacities. Consequently, it has been hypothesized that a new emerging adipocyte secretory profile associated with aging (SASP for senescence associated secretory phenotype) could actively participate to the progressive onset of metabolic diseases related to aging. By proteomic analysis, we identified haptoglobin as a new proinflammatory cytokine overproduced by murine adipose tissue during aging. Our results showed a regulatory feedback loop between adipocyte haptoglobin and senescence state arguing for a role of the cytokine in aging process. Moreover, haptoglobin induced adipocyte metabolic alterations in vitro targeting lipolysis and insulin sensitivity. In vivo validation of haptoglobin's role on metabolic-induced aging are currently ongoing. Our study will allow a better understanding of haptoglobin's role in age-related adipose tissue loss of function and will pave the road for a new therapeutic strategy in the field of metabolism and age-associated pathologies.

Les thérapeutiques antirétrovirales ont permis d’augmenter la survie des personnes vivant avec le VIH (PVVIH). Cependant, de nombreuses comorbidités non liées au VIH émergent et sont une préoccupation majeure dans la prise en charge des patients. L’activation, l’inflammation et l’immunosénescence pourraient jouer un rôle majeur dans ce processus. De nombreux marqueurs existent pour mesurer ces dysfonctionnements et ils ont souvent été considérés sans prendre en compte leurpossible interdépendance. Les objectifs de cette thèse était i) de proposer une combinaison de ces marqueurs, ii) d’évaluer l’association entre la combinaison de ces marqueurs et la présence des comorbidités, et iii) d’évaluer l’association entre la combinaison de ces marqueurs, et le risque de survenue des comorbidités et de la mortalité chez des PVVIH inclus dans la sous étude CIADIS de la cohorte ANRS CO3 Aquitaine. Nous avons identifié deux scores : le score CIADIS cellulaire et soluble. Le score cellulaire était plutôt associé à la multimorbidité et à la survenue d’une nouvelle comorbidité quelle qu’elle soit. Le profil des dysfonctionnements immunitaires sous-jacent était différent lorsque l’on s’intéressait aux comorbidités séparément. Ces résultats soutiennent l’hypothèse que différents profils d’activation, d’inflammation et de sénescence sous-jacents pourraient être impliqués dans le développement de différentes comorbidités. Nos résultats montrent que des analyses intégrant de nouveaux biomarqueurs pourraient accroître la compréhension des comorbidités. Nous allons continuer de travailler sur l’identification des profils de dysfonctionnements immunitaires pour des comorbidités spécifiques. / Antiretroviral therapies have improved the survival of HIV-infected people. However, many non-HIVrelated comorbidities occur and represent a major concern in patient care. Activation, inflammation and immunosenescence could play a major role in this process. Many markers can measure those dysfunctions and they are often used without accounting for their possible interdependency. The objectives of this thesis were i) proposing a combination of those markers, ii) assessing the association between the combination of markers and the presence of comorbidities and iii) assessing the association between the combination of markers and the risk of occurrence of comorbidities and mortality in HIV-infected patients included in the sub-study CIADIS from cohort ANRS CO3 Aquitaine. We identified two scores: the cellular and the soluble CIADIS scores. The cellular score was mostly to multimorbidity and occurrence of any kind of new comorbidity. The profile of underlying immune dysfunctions was different when looking separately at the comorbidities. These results support the assumption that several underlying profiles of activation, inflammation and senescence could be involved in the development of different comorbidities. Our results show that integrating new biomarkers in analyses could improve the understanding of comorbidities. We will continue to work on the identification of profiles of immune dysfunctions for some specific comorbidity.