Efeito do ácido quinolínico na captação de glutamato e na lipoperoxidação em hipocampo e estriato de ratos jovens

39

Dmdmdx/Largemyd: a new mouse model of neuromuscular diseases useful for studying physiopathological mechanisms and testing therapies

Although muscular dystrophies are among the most common human genetic disorders, there are few treatment options available. Animal models have become increasingly important for testing new therapies prior to entering human clinical trials. The Dmdmdx mouse is the most widely used animal model for Duchenne muscular dystrophy (DMD), presenting the same molecular and protein defect as seen in humans with the disease. However, this mouse is not useful for clinical trials because of its very mild phenotype. The mouse model for congenital myodystrophy type 1D, Largemyd, harbors a mutation in the glycosyltransferase Large gene and displays a severe phenotype. To help elucidate the role of the proteins dystrophin and LARGE in the organization of the dystrophin-glycoprotein complex in muscle sarcolemma, we generated double-mutant mice for the dystrophin and LARGE proteins. The new Dmdmdx/Largemyd mouse model is viable and shows a severe phenotype that is associated with the lack of dystrophin in muscle. We tested the usefulness of our new mouse model for cell therapy by systemically injecting them with normal murine mesenchymal adipose stem cells (mASCs). We verified that the mASCs were hosted in the dystrophic muscle. The new mouse model has proven to be very useful for the study of several other therapies, because injected cells can be screened both through DNA and protein analysis. Study of its substantial muscle weakness will also be very informative in the evaluation of functional benefits of these therapies.FAPESP - CEPIDInstituto Nacional de Ciência e Tecnologia em Células-Tronco e Terapia Celular (INCTC) - CNPqFINEPABDIMCAPES / COFECU

Characterization of satellite-cells gene expression profile from dystrophic mice carrying different molecular defects

As células-satélite musculares vêm sendo muito estudadas em diferentes pesquisas, especialmente com o objetivo de aumentar a compreensão do mecanismo de sua ação na regeneração muscular e as respectivas implicações nas diferentes miopatias, visando identificar possíveis alvos terapêuticos. Dois modelos para distrofias, os camundongos Largemy d e Lama2dy2j/J possuem um padrão de degeneração intenso e bastante semelhante, mas com diferenças na expressão de genes envolvidos na cascata de regeneração. Por isso, estes constituem interessantes modelos para o estudo de possíveis diferenças no mecanismo de ativação e atuação das células-satélite no músculo distrófico. Assim, os objetivos específicos deste projeto consistiram em: 1) isolar e caracterizar por citometria de fluxo as populações de células-satélite dos modelos Largemy d e Lama2dy2j/J em comparação com o normal C57Black6, quanto a expressão de marcadores de miogênese e de células-tronco pluripotentes; e 2) estudar e comparar o perfil de expressão gênica destas populações de células satélites através de microarray de expressão. Na caracterização fenotípica das células isoladas do músculo normal, aquelas que aderem mais precocemente (PP1) e mais tardiamente (PP2) mostram um padrão fenotípico semelhante entre si e com características mais próximas às miogênicas. Já a população de células de adesão bem mais tardia (PP6) apresentou um padrão de marcação misto, mantendo as características miogênicas, mas apresentando tambem padrão de células-tronco mesenquimais, sugerindo o fenótipo de células mais imaturas. Nos músculos distróficos, identificamos diferenças na constituição do pool de células presentes inicialmente no músculo, onde na linhagem Lama2dy2j/J há indícios de uma população em estágio proliferativo, enquanto que na linhagem Largemy d há presença de células com maior imaturidade. Os resultados da analise de expressão gênica nas populações caracterizadas se mostraram concordantes com os fenótipos celulares avaliados por citometria. Identificamos a hipo-expressão de genes ligados à regeneração e remodelamento muscular em ambos modelos distróficos. Considerando os genes diferentemente expressos somente em cada um dos modelos, os resultados sugerem ativação de proliferação celular e inibição da diferenciação na linhagem Lama2dy2j/J e distúrbios na miogênese na linhagem Largemy d. Assim, pudemos identificar vias importantes alteradas em cada um dos modelos que explicam parte das diferenças encontradas nos trabalhos anterioresMuscle satellite cells have been widely studied, especially to understand their mechanism of action in muscle regeneration and correspondent implications in the different dystrophic processes, aiming the identification of potential therapeutic targets. Two mice models for muscular dystrophies, Largemyd and Lama2dy2j/J, have a pattern of an intense and very similar degeneration, but with differences in the expression of genes involved in the regeneration cascade. Therefore, they are interesting models to study possible differences in the mechanism of activation and action of satellite cells in the dystrophic muscle. The main objectives of this project are: 1) to isolate and characterize by flow cytometry, populations of satellite cells from Largemyd and Lama2dy2j/J models, as compared to normal C57Black6, evaluating the presence of myogenic and pluripotent stem cells markers; and 2) to study and compare gene expression profiles of these populations of satellite cells using microarray technique. In the phenotypic characterization of cells harvested from normal muscle, both faster (PP1) and slower (PP2) populations to adhere in culture flasks show similar phenotypic characteristics, which were closer to myogenic phenotype. On the other hand, the population of cells with very delayed adhesion ability (PP6) presented a mixed pattern, maintaining the myogenic characteristics, but associated to positive mesenchymal stem cell´s markers, suggesting a phenotype of more immature cells. In dystrophic muscles, we could identify differences in the constitution of the first pool of cells present in the Lama2dy2j/J muscle where there is evidence of a population in proliferative stage, while in the Largemyd strain, we found more immature cells. Gene expression profile in the characterized populations showed consistent concordance with the cellular phenotypes assessed by flow citometry. In both dystrophic models, we identified down-regulated genes related to regeneration and remodeling of the muscle. Considering only the genes differently expressed in each dystrophic model, data suggest the activation of cell proliferation and inhibition of differentiation pathways in Lama2dy2j/J strain and altered myogenesis in the Largemyd model. Thus, we identified important altered pathways in each of the dystrophic models that could explain most of the differences in gene expression profile in the muscle, described in our previous wor

Study of degeneration and regeneration pathways, in mice models for muscular dystrophies

As distrofias musculares constituem um grupo heterogêneo de doenças caracterizadas por uma degeneração progressiva e irreversível da musculatura esquelética. A fraqueza muscular se manifesta quanto existe um desequilíbrio entre os ciclos de degeneração e regeneração, com subseqüente substituição por tecido conjuntivo e adiposo das fibras musculares eliminadas. Diversos fatores estão implicados nestes processos, e as vias de atuação de cada um deles ainda não são totalmente conhecidas. Os mais importantes marcadores da via miogênica são os fatores Myf5, MyoD, Myf6 e miogenina. Os marcadores da degeneração, por sua vez, são o TGFβ-1, citocina inflamatória provavelmente envolvida no processo de fibrose do músculo distrófico, e o aumento da expressão do próprio colágeno, componente da matriz extracelular. O objetivo do presente projeto consistiu em estudar os fatores relacionados com as vias de degeneração e regeneração em modelos murinos distróficos com diferentes defeitos nas proteínas musculares, para elucidação dos mecanismos fisiopatológicos envolvidos, visando terapias. Para tal, foram estabelecidas três abordagens: 1-) Estudar o potencial terapêutico de células-tronco mesenquimais de medulas óssea, nos modelos Lama2dy-2J/J (deficiente para a proteína α2-laminina) e Largemyd (defeito de glicosilação); 2-) Estudar a expressão relativa dos genes envolvidos nas vias de degeneração e regeneração nos diferentes modelos murinos para distrofias musculares; 3-) Estudar o papel da distrofina e α2-laminina na organização do complexo distrofina-glicoproteínas associadas no músculo esquelético, através da produção de um camundongo duplo-mutante deficiente para estas duas proteínas. Na primeira abordagem, células-tronco mesenquimais de medula, expressando a proteína eGFP, foram injetadas por via sistêmica em camundongos Lama2dy-2J/J e Largemyd, mas não foram localizadas posteriormente no músculo dos animais testados. Testes complementares mostraram que células MSC e C2C12 expressando eGFP permanecem por curtos períodos de tempo no tecido injetado, sugerindo que são eliminadas do músculo distrófico em virtude da expressão permanente de eGFP. Análise funcional realizada nestes animais mostrou uma grande heterogeneidade de resposta nos diversos testes aplicados, compatível com a variabilidade clínica também observada em pacientes humanos. Na segunda abordagem, analisamos a expressão dos genes da cascata de degeneração e regeneração nos modelos distróficos mdx, SJL/J, Lama2dy-2J/J e Largemyd, e correlacionamos estes resultados com o padrão histopatológico de cada modelo. Os resultados observados sugerem que o gene TGFβ-1 é ativado pelo processo distrófico em qualquer grau de degeneração, enquanto a ativação da expressão do gene PCOL possivelmente ocorre nos estágios iniciais deste processo. Observou-se também que cada mecanismo patofisiológico atuou de forma diversa na ativação da regeneração, com diferenças na indução da proliferação das células-satélite, mas sem alterações no estimulo à diferenciação. Assim, a disfunção na população de células-satélite pode representar um mecanismo importante na patogênese das distrofias musculares. Na terceira abordagem, um modelo murino duplo-mutante para as proteínas distrofina e α2-laminina foi gerado a partir de cruzamentos das linhagens mdx e Lama2dy-2J/J, com a proporção mendeliana esperada, sendo, portanto, viável. O animal duplo-afetado está apresentando fraqueza muscular mais acentuada que os modelos parentais. Estudos complementares de proteínas musculares serão ainda realizados neste novo modelo para verificar a presença ou não das demais proteínas do DGC e sua relação com o padrão de degeneração/regeneração muscular.The muscular dystrophies are a heterogeneous group of genetic diseases characterized by progressive and irreversible degeneration of skeletal muscles. Muscle weakness is the consequence of an imbalance between successive cycles of degeneration and regeneration, with further replacement of the degraded muscle fibers by adipose and connective tissues. Several factors are involved these processes and the respective functional pathways are still not well known. Myf5, MyoD, Myf6 and myogenin are important factors responsible for the myogenesis and regeneration in the muscle. One important marker for the degeneration is TGF-1, which is an inflammatory cytokine with a possible role in the stimulation of fibrosis in the dystrophic muscle through the activation of genes related to the expression of collagen. The main objective of this project was to study the factors involved in the degeneration and regeneration pathways, in mice models for muscular dystrophies, carrying different defects in muscle proteins, to better understand the involved pathophysiological mechanisms, aiming future therapies. This was done through three strategies: 1-) The study of the therapeutic potential of transplantation of bone marrow mesenchymal-eGFP transformed stem cells, in Lama2dy-2J/J (a2 laminin deficient mice) and Largemyd (mice with defect in the glycosilation of -DG) ; 2-) The analyses of the relative expression of genes involved in regeneration and degeneration, in different mice models for muscular dystrophies; 3-) The study of the roles of dystrophin and 2-laminin proteins in the organization of the dystrophin-glycoprotein complex in muscle sarcolemma through the generation of a new mouse model, double-mutant for these two proteins. In the first approach, bone marrow mesenchymal stem cells expressing eGFP protein were intravenously injected in Lama2dy-2J/J and Largemyd mice, but these cells were not localized in the muscle of the tested animals after 3 months of experiment. Complementary studies showed that MSC and C2C12 cells expressing eGFP, when directly injected in the muscle of these models, were retained for only a few days, suggesting a rejection against cells expressing eGFP in the dystrophic muscle. Functional analysis showed a high variability among the tested mice, which is similar to the significant clinical variability observed in human patients with muscular dystrophies. In the second approach we quantified the expression of genes involved in degeneration and regeneration pathways in the dystrophic models mdx, SJL/J, Lama2dy-2J/J and Largemyd, and correlated these data with muscle histopathological pattern of each model. The result suggests that TGFβ-1 gene is activated in the dystrophic process in all the stages of degeneration while the activation of the expression of the PCOL gene possibly occurs in earliest stages of this process. We also observed that each physiopathological mechanism acted differently in the activation of regeneration, with differences in the induction of proliferation of satellite cells, but with no alterations in stimulation to differentiation. Dysfunction of satellite cells can therefore be an important additional mechanism of pathogenesis in the dystrophic muscle. In the third approach we generated a new dystrophic mouse model, carrying two simultaneous deficiencies of the proteins dystrophin and 2-laminin, by crossing mdx and Lama2dy-2J/J strains. In the offspring, the proportion of affected double-mutant mice was within the expected mendelian proportion, showing therefore, the viability of these defects with life. Only 4 alive animals were obtained up to the present date, and they are being followed for clinical characterization. The phenotype of this double-mutant mouse is very severe, presenting significant weakness, starting earlier and progressing faster that the parental strains. When more affected animals will be available, additional protein studies will be done to verify the effect of these two deficiencies in the organization of the DGC complex and its effect on the cascades of muscle degeneration and regeneration

Jornal da Universidade, 2018, v. 21, n. 210, mar. Caderno JU, n. 54

Expõe as dificuldades enfrentadas pelos alunos da UFRGS para se adaptarem a rotina de estudos exigida pelos cursos da Universidade.2018, n. 54Porto Alegr

Knowledge of undergraduate nursing students about human papillomavirus vaccine

Objective: to identify the knowledge that undergraduate nursing students have about human papillomavirus vaccine. Methods: field research, descriptive, cross-sectional. Sample composed of 100 undergraduate nursing students of a private university, with use of a questionnaire. Data were analyzed using descriptive statistics. Results: among participants, 98.0% reported that they knew the human papillomavirus vaccine, 65.0% recognized the types of viruses against which the vaccine gives protection, and 51.0% had knowledge about the age group that is targeted to receive the vaccine in the public healthcare network. As for the features of the administration of the vaccine, such as dosage, route of administration, contraindications and adverse events, a level of knowledge below 60.0% was observed. Conclusion: insufficient knowledge on the human papillomavirus vaccine was found among the students participating in the present study and this stresses the need to give more attention to the discussion about the prevention of cervical cancer during the training of future nurses

The mdx Mutation in the 129/Sv Background Results in a Milder Phenotype: Transcriptome Comparative Analysis Searching for the Protective Factors.

The mdx mouse is a good genetic and molecular murine model for Duchenne Muscular Dystrophy (DMD), a progressive and devastating muscle disease. However, this model is inappropriate for testing new therapies due to its mild phenotype. Here, we transferred the mdx mutation to the 129/Sv strain with the aim to create a more severe model for DMD. Unexpectedly, functional analysis of the first three generations of mdx129 showed a progressive amelioration of the phenotype, associated to less connective tissue replacement, and more regeneration than the original mdxC57BL. Transcriptome comparative analysis was performed to identify what is protecting this new model from the dystrophic characteristics. The mdxC57BL presents three times more differentially expressed genes (DEGs) than the mdx129 (371 and 137 DEGs respectively). However, both models present more overexpressed genes than underexpressed, indicating that the dystrophic and regenerative alterations are associated with the activation rather than repression of genes. As to functional categories, the DEGs of both mdx models showed a predominance of immune system genes. Excluding this category, the mdx129 model showed a decreased participation of the endo/exocytic pathway and homeostasis categories, and an increased participation of the extracellular matrix and enzymatic activity categories. Spp1 gene overexpression was the most significant DEG exclusively expressed in the mdx129 strain. This was confirmed through relative mRNA analysis and osteopontin protein quantification. The amount of the 66 kDa band of the protein, representing the post-translational product of the gene, was about 4,8 times higher on western blotting. Spp1 is a known DMD prognostic biomarker, and our data indicate that its upregulation can benefit phenotype. Modeling the expression of the DEGs involved in the mdx mutation with a benign course should be tested as a possible therapeutic target for the dystrophic process

Intoxicação por metilmercúrio através do leite materno : efeitos sobre o sistema glutamatérgico cerebelar

42