Project description:The survival motor neuron 1 (SMN1) gene is the causative gene for the spinal muscular atrophy (SMA) disease, the first genetic cause of infant mortality. It affects primarily motor neurons which are the targets of the approved genetic therapies aimed to compensate for the loss of SMN1. However, the limitations of these therapies are now evident since they are not cures, and alternative strategies need to be investigated. Because of the ubiquitous and multifunctional roles of SMN1 in the cell, deeper understanding of the molecular mechanisms underlying intrinsic abnormalities of the different tissues affected by SMA is crucial for the development of new therapeutic approaches. Here we used a muscle specific genetic mouse model for the identification of key cellular processes associated to SMN1 loss, at single myofiber level. We found that mitochondrial dysfunction is a key pathogenetic event in SMA: mitochondria are abnormal with internal degenerated cristae. The ultrastructural changes are coincident with alterations in ROS levels by monoamine oxidase A and Ca2+ homeostasis. Interestingly, the improvements of the myopathic phenotype of the muscle-specific SMA model mice by transplantation of amniotic fluid stem (AFS) cells led to restore mitochondrial function. Our data suggest that a mitochondria-targeting therapy may represent a complementary and broad treatment strategy to further optimize the current treatment.
Project description:Study of gene expression profiles of muscular and neuronal mouse mutant of spinal muscular atrophy(SMA). Pre and post symptomatic stage disease have been analyzed.
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.