Project description:Recent genetic studies of ALS patients have identified several forms of ALS that are associated with mutations in RNA binding proteins. In animals or cultured cells, such defects broadly affect RNA metabolism. This raises the question of whether all forms of ALS have general effects on RNA metabolism. We tested this hypothesis in a mouse model of ALS that is transgenic for a human disease-causing mutation in the enzyme superoxide dismutase 1 (SOD1). We analyzed RNA from laser-captured spinal cord motor neuron cell bodies of the mutant SOD1 strain, comparing the RNA profile with that from a corresponding wild-type SOD1 transgenic strain. We prepared the samples from animals that were presymptomatic, but which manifested abnormalities at the cellular level that are seen in ALS, including aggregation of the mutant protein in motor neuron cell bodies and defective morphology of neuromuscular junctions, the connections between neuron and muscle. We observed only minor changes in the level and splicing of RNA in the SOD1 mutant animals as compared with wild-type, suggesting that mutant SOD1 produces the toxic effects of ALS by a mechanism that does not involve global RNA disturbance. RNA-Seq of laser microdissection of motor neuron bodies from two biological replicates each of SOD1 YFP (wildtype 592) and SOD1 G85R YFP (737) transgenic mice.
Project description:Recent genetic studies of ALS patients have identified several forms of ALS that are associated with mutations in RNA binding proteins. In animals or cultured cells, such defects broadly affect RNA metabolism. This raises the question of whether all forms of ALS have general effects on RNA metabolism. We tested this hypothesis in a mouse model of ALS that is transgenic for a human disease-causing mutation in the enzyme superoxide dismutase 1 (SOD1). We analyzed RNA from laser-captured spinal cord motor neuron cell bodies of the mutant SOD1 strain, comparing the RNA profile with that from a corresponding wild-type SOD1 transgenic strain. We prepared the samples from animals that were presymptomatic, but which manifested abnormalities at the cellular level that are seen in ALS, including aggregation of the mutant protein in motor neuron cell bodies and defective morphology of neuromuscular junctions, the connections between neuron and muscle. We observed only minor changes in the level and splicing of RNA in the SOD1 mutant animals as compared with wild-type, suggesting that mutant SOD1 produces the toxic effects of ALS by a mechanism that does not involve global RNA disturbance.
Project description:Amyotrophic Lateral Sclerosis (ALS) is generally a late onset neurodegenerative disease. Mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene accounts for approximately 20% of familial ALS and 2% of all ALS cases. Although a number of hypothesis have been proposed to explain mutant SOD1 toxicity, the molecular mechanisms of the disease remain unclear. SOD1 linked ALS is thought to function in a non-cell autonomous manner such that the motoneurons are critical for the onset and glia contribute to the progress of the disease. To dissect the roles of motoneurons and glia, we used the Gal4-UAS system to determine gene expression changes following the expression of mutant human SOD1 (G85R) selectively in either motoneurons or glia, and concurrently in motoneurons and glia of flies. We conducted a microarray on young (5 days old) and old (45 days old) flies expressing G85R in these cell types and identified a number of genes involved in a variety of processes. The candidate genes identified by this screen may help elucidate the individual and combined contributions of motoneurons and glial cells in ALS. We used microarrays to evaluate the transcriptional profile of 5 day old and 45 day old flies expressing mutant human SOD1 (G85R) in a tissue specific manner in motoneurons, glia, and together in motoneurons and glia and compared the expression to flies expressing wild-type drosophila SOD1 controls. The Gal4-UAS system was used to drive tissue expression of either mutant human SOD1 (G85R) or wild-type drosophila SOD1 (dSOD1) in flies. Flies containing either the motoneuronal driver, D42-Gal4, the glial driver, M1B-Gal4, or the combined motoneuronal and glial drivers, D42+M1B-Gal4 were crossed to flies containing either mutant human SOD1, UAS-G85R, or wild-type drosophila SOD1, UAS-dSOD1, as a control. Adult male progeny were collected within 24 hours after eclosion and aged to 5 (5d) and 45 (45d) days old. Groups of 10 flies were maintained in vials of cornmeal agar food and transferred to fresh food every 5-7 days. For each Gal4-UAS line and each age, 3 biological replicates consisting of 40 whole flies were flash frozen in liquid nitrogen and used to isolate total RNA, for a total of 36 samples.
Project description:Amyotrophic Lateral Sclerosis (ALS) is generally a late onset neurodegenerative disease. Mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene accounts for approximately 20% of familial ALS and 2% of all ALS cases. Although a number of hypothesis have been proposed to explain mutant SOD1 toxicity, the molecular mechanisms of the disease remain unclear. SOD1 linked ALS is thought to function in a non-cell autonomous manner such that the motoneurons are critical for the onset and glia contribute to the progress of the disease. To dissect the roles of motoneurons and glia, we used the Gal4-UAS system to determine gene expression changes following the expression of mutant human SOD1 (G85R) selectively in either motoneurons or glia, and concurrently in motoneurons and glia of flies. We conducted a microarray on young (5 days old) and old (45 days old) flies expressing G85R in these cell types and identified a number of genes involved in a variety of processes. The candidate genes identified by this screen may help elucidate the individual and combined contributions of motoneurons and glial cells in ALS. We used microarrays to evaluate the transcriptional profile of 5 day old and 45 day old flies expressing mutant human SOD1 (G85R) in a tissue specific manner in motoneurons, glia, and together in motoneurons and glia and compared the expression to flies expressing wild-type drosophila SOD1 controls.
Project description:Extracellular vesicles (EVs) are secreted by myriad cells in culture and also by unicellular organisms, and their identification in mammalian fluids suggests that EV release also occurs at the organism level. However, although it is clearly important to better understand EVs' roles in organismal biology, EVs in solid tissues have received little attention. Here, we modified a protocol for EV isolation from primary neural cell culture to collect EVs from frozen whole murine and human neural tissues by serial centrifugation and purification on a sucrose gradient. Quantitative proteomics comparing brain-derived EVs from nontransgenic (NTg) and a transgenic amyotrophic lateral sclerosis (ALS) mouse model, superoxide dismutase 1 (SOD1) G93A , revealed that these EVs contain canonical exosomal markers and are enriched in synaptic and RNA-binding proteins. The compiled brain EV proteome contained numerous proteins implicated in ALS, and EVs from SOD1 G93A mice were significantly depleted in myelin-oligodendrocyte glycoprotein compared with those from NTg animals. We observed that brain- and spinal cord–derived EVs, from NTg and SOD1 G93A mice, are positive for the astrocyte marker GLAST and the synaptic marker SNAP25, whereas CD11b, a microglial marker, was largely absent. EVs from brains and spinal cords of the SOD1 G93A ALS mouse model, as well as from human SOD1 familial ALS patient spinal cord, contained abundant misfolded and nonnative disulfide-cross-linked aggregated SOD1. Our results indicate that CNS-derived EVs from an ALS animal model contain pathogenic disease-causing proteins and suggest that brain astrocytes and neurons, but not microglia, are the main EV source.
Project description:Amyotrophic lateral sclerosis (ALS) is caused by the progressive degeneration of motor neurons. Mutations in the Cu/Zn superoxide dismutase (SOD1) are found in about 20% of patients with familial ALS. Mutant SOD1 causes motor neuron death through an acquired toxic property. Although, molecular mechanism underlying this toxic gain-of-function remains unknown, evidence support the role of mutant SOD1 expression in non-neuronal cells in shaping motor neuron degeneration. We have previously found that in contrast to non-transgenic, SOD1G93A-expressing astrocytes induced apoptosis of co-cultured motor neurons. This prompted us to investigate whether the effect on motor neuron survival was related to a change in the gene expression profile. Through high-density oligonucletide microarrays we found changes in the expression of genes involved in transcription, signaling, cell proliferation, extracellular matrix construction, response to stress and steroid and lipid metabolism. Decorin, a small multifunctional proteoglycan, was the most up-regulated gene. Down-regulated genes included the insulin-like growth factor-1 receptor and the RNA binding protein ROD1. We also analyzed the expression of selected genes in purified motor neurons expressing SOD1G93A and in spinal cord of asymptomatic and early symptomatic ALS-rodent model. The expression of mutated SOD1 in astrocytes cause gene expression changes with potential consequences for its interaction with motor neurons. The astrocyte-specific gene expression profile contributes to the identification of possible candidates for cell type-specific therapies in ALS Keywords: Cell type comparison
Project description:Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease caused by loss of motor neurons. SOD1 may have a toxic role in the pathogenesis of ALS when the protein aggregates in the cytoplasm; increased accumulation of soluble nuclear SOD1 (nSOD1) represents a protective cellular reaction.
Project description:Although many distinct mutations in a variety of genes are known to cause Amyotrophic Lateral Sclerosis (ALS), it remains poorly understood how they selectively impact motor neuron biology and whether they converge on common pathways to cause neural degeneration. Here, we have combined reprogramming and stem cell differentiation approaches with genome engineering and RNA sequencing to define the transcriptional changes that are induced in human motor neurons by mutant SOD1. Mutant SOD1 protein induced a transcriptional signature indicative of increased oxidative stress, reduced mitochondrial function, altered sub-cellular transport as well as activation of the ER stress and unfolded protein response pathways. Functional studies demonstrated that perturbations in these pathways were indeed the source of altered transcript levels.
Project description:Amyotrophic lateral sclerosis (ALS) is a paralytic degenerative disease of the nervous system. In the SOD1 mouse model of ALS we found loss of the molecular and functional microglia signature associated with pronounced expression of miR-155 in SOD1 mice. We also found increased expression of miR-155 in the spinal cord of ALS subjects. Genetic ablation of miR-155 increased survival in SOD1 mice and reversed the abnormal microglial and monocyte molecular signature. In addition, dysregulated proteins in the spinal cord of SOD1 mice that we identified in human ALS spinal cords and CSF were restored in SOD1G93A/miR155-/- mice. Treatment of SOD1 mice with anti-miR-155 SOD1 mice injected systemically or into the cerebrospinal fluid prolonged survival and restored the microglial unique genetic and microRNA profiles. Our findings provide a new avenue for immune based therapy of ALS by targeting miR-155. Total RNA was isolated from whole lumbar spinal cord homogenate from healthy control donors without known neurologic diseases and sporadic and familial ALS.