Yes / Background: Understanding and countering the well-established negative health consequences of spaceflight remains a primary challenge preventing safe deep space exploration. Targeted/personalized therapeutics are at the forefront of space medicine strategies, and cross-species molecular signatures now define the 'typical' spaceflight response. However, a lack of direct genotype-phenotype associations currently limits the robustness and, therefore, the therapeutic utility of putative mechanisms underpinning pathological changes in flight. Methods: We employed the worm Caenorhabditis elegans as a validated model of space biology, combined with 'NemaFlex-S' microfluidic devices for assessing animal strength production as one of the most reproducible physiological responses to spaceflight. Wild-type and dys-1 (BZ33) strains (a Duchenne muscular dystrophy (DMD) model for comparing predisposed muscle weak animals) were cultured on the International Space Station in chemically defined media before loading second-generation gravid adults into NemaFlex-S devices to assess individual animal strength. These same cultures were then frozen on orbit before returning to Earth for next-generation sequencing transcriptomic analysis. Results: Neuromuscular strength was lower in flight versus ground controls (16.6% decline, p

This study analyzed the research on older adults and resistance training exercise and assessed effects on health span and lowering disability rates. A targeted search of the literature was employed using the following key words: sarcopenia, resistance training, hypertrophy, quality of life, disability, activities of daily living, strength training, falls, and functional strength. These were used to find articles that were relevant to the research. Articles were excluded if they focused on young athletes as they did not meet my research age group. Articles that focused on nutrition were also excluded as they pulled the focus away from the impact of resistance training on sarcopenia. The final exclusion that was made was to avoid any articles that made the focus on aerobic exercise as opposed to the focus being on resistance training. The age range of the participants was 60 years old to 93 years old. The results of the study saw that out 20 studies/sources cited shows that resistance training has been shown to increase the overall health, both mental and physical, of the 65+ population. Resistance training has been shown to increase functional capacity and ability to do activities of daily living, most importantly it reduces fall risk in the 65+ population. Finally, by helping to reduce fall risk and increasing overall health, resistance training has been shown to reduce the risk of disability in elderly adults. In conclusion, the risk of falls and serious consequences were reduced as the functional capacity and muscular strength of the elderly population increased. Overall, strength training has a positive effect on the elderly population and contributes to them maintaining their health, independence, and quality of life as long as possible.

Spinal muscular atrophy (SMA) is a devastating disorder caused by deletions and mutations in the survival of motor neuron (SMN1) gene and is marked by motor neuron loss and muscle weakness. While its genetic basis is clear, the underlying molecular mechanisms remain elusive. Decreased levels of the survival of motor neuron (SMN) protein, encoded by the SMN1 gene, are implicated in SMA pathology. Despite splicing has been under the spotlight as a major mechanism impaired in SMA, recent evidence suggests that SMN deficiency also disrupts protein translation in vivo in a mouse model of severe SMA, complicating SMA's molecular landscape. This thesis examines the impact of SMN protein loss on translation in SMA mouse models across tissues, post-natal and pre-natal disease stages, focusing on both mild (Chapter 1) and severe forms of SMA (Chapter 2) respectively. To tackle this question, in this thesis, I took advantage of multiple cutting-edge and sequencing-based techniques (ribosome profiling and RNA-seq) coupled with biochemical and molecular biology-based assay (polysome profiling, co-sedimentation profiles, qPCR, and western blotting), which applied to study in molecular detail the translational defects in the brain, spinal cord and liver at asymptomatic, pre-symptomatic and early symptomatic stages of SMA. Polysome profiling in control mice (Smn2B/+) reveals a gradual increase in SMN association with ribosomes/polysomes during postnatal development, indicating dynamic SMN function in protein translation during post-natal development. In SMA condition, where SMN protein levels drop, this binding reveals a tissue-specific decrease in the spinal cord and liver. Through ribosome profiling, numerous alterations in translation were identified at the pre-symptomatic stage of the disease, suggesting that translational defects are features of the early stages of SMA. Importantly these alterations are independent of transcriptional and splicing changes. Although no gene was found to be in common, I found that genes altered in at least 2 tissues are involved in the same processes. The dysregulated mRNAs exhibit rare codons at the beginning of coding sequences in all three tissues, as shown in the case of the severe model of SMA. 4 From these common processes I have identified specific mRNA targets that play key roles in the organization of the extracellular matrix I validated the presence of translational changes in Col1a1, Col1a2, and Spp1 highlighted effects of SMN deficiency on translational regulation, in the absence of transcriptional alterations. Validation studies in both mice and SMA patient-derived fibroblasts further underscored the potential of translational dysregulation and drop in Col1a1 protein expression during SMA progression. Finally, prenatal studies have revealed distinct translational changes in embryonic tissues from Taiwanese mice. Despite no alterations in global translation, a drop in SMN association with ribosomes/polysomes and tissue-specific differences in ribosome occupancy were observed. Also, in this case, dysregulated mRNAs exhibit rare codons at the beginning of coding sequences. These findings shed light on the unique molecular landscape of prenatal development in the context of SMN deficiency. In summary, this study provides insights into translation dysregulation in SMA pathology, emphasizing tissue-specific effects and developmental stage-dependent alterations. By elucidating the complex relationship between SMN protein function and translational dynamics, it lays the groundwork for targeted therapeutic strategies and biomarkers to improve SMA management. Ongoing investigations into prenatal development and translation dynamics are crucial for a comprehensive understanding of SMA pathogenesis and effective treatment development.

A amiotrofia espinal (AEP) é a mais freqüente das doenças neuromusculares (DNM) responsáveis pela Síndrome da Criança Hipotônica (SCH), causada pela degeneração das células do corno anterior da medula espinhal. O comprometimento neurológico se estabelece de forma rápida e intensa nos primeiros meses de vida de tal maneira que, em pouco tempo, a única atividade motora voluntária persistente pode ser a motricidade ocular. O Ácido Valpróico é um medicamento de fácil aquisição e administração, demonstrou-se eficaz em evitar a deleção do exon 7, o que prolongaria ainda mais a sobrevivência dos neurônios. Com base nesta nova perspectiva terapêutica para esta drástica doença e por não existir nenhuma forma de avaliação motora validada e de fácil reprodutibilidade, foi desenvolvido um protocolo de avaliação física-funcional para acompanhamento deste grupo de pacientes e de outros com a SCH, com o objetivo de avaliar quantitativamente e qualitativamente a evolução de aquisição motora nos pacientes, selecionando provas funcionais e criando uma nova forma de avaliação utilizando o recurso da filmagem para posterior examinação, de fácil aplicação em consultório, que permitam uniformizar a interpretação dos resultados em diferentes pesquisas ou individualmente ao longo de um acompanhamento clínico. Cinco pacientes com AEP-I, com idades variando de 04 a 18 meses, sem a necessidade de auxílio respiratórios, e submetidos à intervenção medicamentosa com o Ácido Valpróico, foram avaliados em 05 visitas, totalizando um acompanhamento de 2 meses e meio. A análise das aquisições motoras obedeceu a um roteiro de movimentação utilizando a filmagem e posteriormente atribuindo uma pontuação. Os resultados demonstraram que todas as crianças participantes do estudo não apresentaram piora do quadro motor, o que seria esperado pela evolução natural da doença. Consideramos assim que: os pacientes submetidos à intervenção medicamentosa com o Ácido Valpróico apresentaram uma tendência à melhora das aquisições motoras, em relação ao descrito na evolução natural da doença e a utilização da filmagem como método de análise de aquisição motora se mostrou ser um recurso eficaz no acompanhamento da evolução motora dos pacientes. / The spinal muscle atrophy (SMA) is the most frequent neuromuscular disease responsible for Hypotonic Children Syndrome (HCS). SMA is caused by anterior horn cells degeneration in the narrow. The neurological impairment is quickly and strongly established in the first months of life, so, after few months, the only movement that the children can do is moving the eyes. The Valproic acid is a drug easy to buy and to manage, and seems to avoid exon 7 deletion, which could prolong the neurons life. By this new therapeutic knowledge, and for don\'t exist a validate and easy to reproduce way to evaluate the motor function, there were made a functional evaluation protocol to follow the group of patients with SMA and other patients with HCS, with the purpose to qualify and to quantify the motor gain in these patients, creating a new form to evaluate, using film to exam in the end. It\'s easy to apply in the office and can became the only way to evaluate the results in different trials. There were evaluate five patients with SMA type 1, ages from 04 to 18 months, without respiratory assistance use, underwent to Valproic acid intervention. They were evaluated in five visits, in a total 2 years and a half of following. The motor acquisitions were made from the film and scores. The results showed that no one off al children presented a motor loss, which would be expected for the natural evolution of SMA type 1. Consequently, the patients that underwent to valproic acid trial presented a tendency to gain motor abilities when compared to the natural evolution of the disease and the film as an analyze method seem to be an efficient way to follow the motor evolution of these patients.

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on March 10, 2010). Vita. Thesis advisor: Lorson, Christian L. "December 2008" Includes bibliographical references

A amiotrofia espinal (AEP) é a mais freqüente das doenças neuromusculares (DNM) responsáveis pela Síndrome da Criança Hipotônica (SCH), causada pela degeneração das células do corno anterior da medula espinhal. O comprometimento neurológico se estabelece de forma rápida e intensa nos primeiros meses de vida de tal maneira que, em pouco tempo, a única atividade motora voluntária persistente pode ser a motricidade ocular. O Ácido Valpróico é um medicamento de fácil aquisição e administração, demonstrou-se eficaz em evitar a deleção do exon 7, o que prolongaria ainda mais a sobrevivência dos neurônios. Com base nesta nova perspectiva terapêutica para esta drástica doença e por não existir nenhuma forma de avaliação motora validada e de fácil reprodutibilidade, foi desenvolvido um protocolo de avaliação física-funcional para acompanhamento deste grupo de pacientes e de outros com a SCH, com o objetivo de avaliar quantitativamente e qualitativamente a evolução de aquisição motora nos pacientes, selecionando provas funcionais e criando uma nova forma de avaliação utilizando o recurso da filmagem para posterior examinação, de fácil aplicação em consultório, que permitam uniformizar a interpretação dos resultados em diferentes pesquisas ou individualmente ao longo de um acompanhamento clínico. Cinco pacientes com AEP-I, com idades variando de 04 a 18 meses, sem a necessidade de auxílio respiratórios, e submetidos à intervenção medicamentosa com o Ácido Valpróico, foram avaliados em 05 visitas, totalizando um acompanhamento de 2 meses e meio. A análise das aquisições motoras obedeceu a um roteiro de movimentação utilizando a filmagem e posteriormente atribuindo uma pontuação. Os resultados demonstraram que todas as crianças participantes do estudo não apresentaram piora do quadro motor, o que seria esperado pela evolução natural da doença. Consideramos assim que: os pacientes submetidos à intervenção medicamentosa com o Ácido Valpróico apresentaram uma tendência à melhora das aquisições motoras, em relação ao descrito na evolução natural da doença e a utilização da filmagem como método de análise de aquisição motora se mostrou ser um recurso eficaz no acompanhamento da evolução motora dos pacientes. / The spinal muscle atrophy (SMA) is the most frequent neuromuscular disease responsible for Hypotonic Children Syndrome (HCS). SMA is caused by anterior horn cells degeneration in the narrow. The neurological impairment is quickly and strongly established in the first months of life, so, after few months, the only movement that the children can do is moving the eyes. The Valproic acid is a drug easy to buy and to manage, and seems to avoid exon 7 deletion, which could prolong the neurons life. By this new therapeutic knowledge, and for don\'t exist a validate and easy to reproduce way to evaluate the motor function, there were made a functional evaluation protocol to follow the group of patients with SMA and other patients with HCS, with the purpose to qualify and to quantify the motor gain in these patients, creating a new form to evaluate, using film to exam in the end. It\'s easy to apply in the office and can became the only way to evaluate the results in different trials. There were evaluate five patients with SMA type 1, ages from 04 to 18 months, without respiratory assistance use, underwent to Valproic acid intervention. They were evaluated in five visits, in a total 2 years and a half of following. The motor acquisitions were made from the film and scores. The results showed that no one off al children presented a motor loss, which would be expected for the natural evolution of SMA type 1. Consequently, the patients that underwent to valproic acid trial presented a tendency to gain motor abilities when compared to the natural evolution of the disease and the film as an analyze method seem to be an efficient way to follow the motor evolution of these patients.

No description available.

Therapeutic approaches leading to the stimulation of regeneration, and/or inhibition of degeneration processes in neuromuscular disorders are believed to offer valid therapeutic strategies that would preserve muscle tone and contribute to the quality of life while lengthening patient life span. Activation of CalcineurinA (CnA), a threonine-serine phosphatase, controls gene regulatory programs in skeletal muscle by stimulating slow muscle fiber (type I) gene expression. This phosphatase has been also identified as a key mediator in the hypertrophic response and in skeletal muscle regeneration. Activation of CnA is, therefore, considered as a potentially interesting means of stimulating muscle regeneration in myopathies. We have identified a peptide aptamer that activates CnA in vitro, in cells and in vivo. In a mouse model for denervation-induced muscle atrophy, CnA-activating peptide aptamers show significant positive impact. This is reflected in larger overall muscle cross-sectional surface area due to an increased number of fibers and larger individual fiber surface area. Insight into the biological mechanism is afforded by observation of increased levels of nuclear NFAT transcription factor in these fibers, in agreement with peptide aptamer-mediated activation of CnA. Furthermore, a significant increase in central nuclei, characteristic of the presence of new fibers, is observed in muscles treated with the peptide aptamers specifically activating CnA. Identification of the specific binding site of the peptide aptamer on CnA was achieved using several truncations of the phosphatase, offering insight into the molecular mechanism of action. Together, these studies offer the first proof that direct activation of endogenous CnA has a measureable impact on cellular responses resulting in stimulation of muscle regeneration and enhancement of pathophysiological state in selected animal models.

Les protéines SREBP-1, Sterol Response Element Binding Proteins, sont des régulateurs clés du métabolisme des lipides et du cholestérol. A ce titre, ils ont été largement étudiés dans le foie et le tissu adipeux. Les facteurs SREBP-1 sont également exprimés dans le muscle squelettique au sein duquel ils sont les principaux médiateurs des effets géniques de l’insuline.Les travaux de thèse présentés dans ce manuscrit ont eu pour but de définir le rôle spécifique de SREBP-1 dans le muscle squelettique. L’étude transcriptomique de cellules musculaires humaines révèle plus de1500 gènes régulés par SREBP-1 dans le muscle squelettique humain, dont la moitié est réprimée. L’analyse fonctionnelle de ces gènes révèle l’implication de SREBP-1 dans des fonctions musculaires dépassant la cadre du métabolisme glucido-lipidique. Ainsi, SREBP-1 inhibe l’expression de plusieurs gènes impliqués dans la différenciation et le maintien du phénotype musculaire. En conséquence, la sur expression de SREBP-1 bloque la différenciation myogénique in vitro et induit une atrophie marquée in vitro, sur des myotubes différenciés et in Vivo, dans le muscle squelettique de souris.En parallèle, deux répresseurs transcriptionnels : BHLHB2 et BHLHB3 apparaissent, après étude de leur promoteur, comme deux nouvelles cibles directes de SREBP-1. Ainsi, 20% des gènes inhibés par SREBP-1sont des cibles de BHLHB2 et BHLHB3, de nombreux gènes muscle-spécifiques y compris. De plus, BHLHB2 apparaît, de la même façon que SREBP-1, comme un acteur essentiel dans l’action de l’insuline sur le muscle squelettique, et dans le développement de l’insulino-résistance musculaire chez les patients diabétiques de type2.Le blocage de la différenciation myogénique et l’atrophie induite par SREBP-1 in vitro étant reversées par l’inhibition de l’expression de BHLHB2 et BHLHB3, nous concluons que BHLHB2 et BHLHB3 sont responsables de l’effet répressif de SREBP-1 sur le phénotype musculaire.Ces résultats mettent donc en évidence un nouveau rôle pour les facteurs SREBP-1 dans la régulation de la myogenèse et le maintien de la masse musculaire. SREBP-1 intègrent ainsi la régulation métabolique au contrôle du phénotype musculaire / Transcription factors SREBP-1, Sterol Response Element Binding Proteins, are key regulators of lipid and cholesterol homeostasis. Their function has been largely studied in liver and adipose tissue, but they are also well expressed in skeletal muscle where they mediate insulin transcriptional effects.This work aims to define the muscle specific role of SREBP-1. Microarray analysis of human myotubes over-expressing SREBP-1 identifies more than 1500 SREBP-1 target genes in human skeletal muscle, including number of repressed genes. Gene ontology analysis reveals the involvement of SREBP-1 in a large variety of biological functions in muscle cells. In fact, SREBP-1 represses expression of a number of muscle-specific genes and markers of muscle differentiation. As a result, SREBP-1 over-expression leads to blockage of in vitro myogenic differentiation and marked atrophy in vitro as in Vivo.In the same time, we identified the transcriptional repressors BHLHB2 and BHLHB3 as new direct target genes of SREBP-1, by promoter analysis. 20% of SREBP-1 repressed genes are also target genes of BHLHB2 and BHLHB3. Furthermore, BHLHB2, like SREBP-1, is involved in insulin action on skeletal muscle and muscular insulin-resistance in type 2 diabetic patients.As SREBP-1 effects on atrophy and myogenic differentiation inhibition are reversed by silencing BHLHB2 and BHLHB3 expression, we can conclude that BHLHB2 and BHLHB3 mediate negative SREBP-1action on muscular phenotype.These results confer a new role for SREBP-1 in the regulation of muscle mass and muscle cell differentiation, thus linking the control of muscle mass to metabolic pathways

La mesure de la perte du volume cérébral est un marqueur IRM de la neurodégénérescence dans la sclérose en plaques. Les techniques actuelles permettent de quantifier soit directement la perte de volume cérébral entre deux examens, soit de la mesurer indirectement à partir du volume cérébral de chaque examen. La fiabilité de ces techniques reste difficile à évaluer en l’absence de gold standard. Ce travail a consisté premièrement, en une étude de reproductibilité réalisée chez 9 patients à partir d’acquisitions semestrielles (3 IRM), sur deux machines différentes et post-traitées par sept algorithmes : BBSI, FreeSurfer, Intégration Jacobienne, KNBSI, un algorithme Segmentation / Classification, SIENA et SIENAX. Deuxièmement, un suivi longitudinal et prospectif a été effectué chez 90 patients SEP. L’étude des variabilités inter-techniques et inter-sites a montré que les techniques de mesures indirectes (Segmentation/Classification, FreeSurfer) et SIENAX fournissaient des pourcentages d’atrophie hétérogènes. A l’inverse, les techniques de mesures directes telles que BBSI, KNBSI, Intégration Jacobienne et à un moindre degré SIENA obtenaient des résultats reproductibles. Toutefois BBSI, KNBSI et l’Intégration Jacobienne obtenaient des pourcentages faibles, suggérant une possible sous-estimation de l’atrophie. L’évaluation de la perte du volume cérébral par Intégration Jacobienne a montré sur 2½ ans de suivi, une atrophie de 1,21% pour les 90 patients et de 1,55%, 1,51%, 0,84%, 1,21% respectivement pour les patients CIS, RR, SP et PP. A l’avenir l’évaluation de la perte de volume cérébral impose des défis d’ordre technique afin d’améliorer la fiabilité des algorithmes actuels. / Brain volume loss is currently a MRI marker of neurodegeneration in MS. The available algorithms for its quantification perfom either direct measurements, or indirect measurements. Their reliability remains difficult to assess especially since there is no gold standard technique. This work consisted first, in a reproducibility study performed on nine patients’ biannual MRI acquisitions (3 time points). These acquisitions were performed on two different MRI systems. Post-processing was applied using seven algorithms: BBSI, FreeSurfer, Jacobian Integration, KNBSI, an algorithm based on segmentation/classification, SIENA and SIENAX. Second, a longitudinal and prospective study was performed in 90 MS patients. The study of inter-technique and inter-site variabilities showed that direct measurement techniques and SIENAX provided heterogeneous values of atrophy. In contrast, indirect measurement algorithms such as BBSI, KNBSI, Jacobian Integration and to a lesser extent SIENA obtained reproducible results. However BBSI, KNBSI and Jacobian Integration algorithms showed lower percentages, suggesting a possible underestimation of atrophy. The evaluation of brain volume loss by Jacobian Integration has shown an atrophy rate of 1.21% over 2 ½ years of the 90 patients’ follow up, and of 1.55%, 1.51%, 0.84%, 1.21% for CIS, RR, SP and PP patients respectively. Jacobian Integration showed its importance in individual monitoring. In the future, assessing brain volume loss requires overcoming of some technical challenges to improve the reliability of the currently available algorithms.