Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
Project description:Spinal motor neurons deficiency results in a series of devastating disorders such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA) and spinal cord injury (SCI). These devastating disorders are currently incurable, while human pluripotent stem cells (hPSCs) derived spinal motor neurons are promising but suffered by low-efficiency, functional immaturity and lacks of posterior cell identity. In this study, we have established human spinal cord neural progenitor cells (hSCNPCs) via hPSCs differentiated neuromesodermal progenitors (NMPs) and demonstrated the hSCNPCs can be continuously expanded up to 40 passages. hSCNPCs can be rapidly differentiated into posterior spinal motor neurons with high efficiency. The functional maturity has been examined in detail. Moreover, a co-culture scheme which is compatible for both neural and muscular differentiation is developed to mimic the neuromuscular junction (NMJ) formation in vitro. Together, these studies highlight the potential avenues for generating clinically relevant motor neurons and modelling neuromuscular diseases through our defined hSCNPCs.
Project description:Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations of the survival of motor neuron 1 (SMN1) gene. In the pathogenesis of SMA, pathological changes of the neuromuscular junction (NMJ) precede the motor neuronal loss. Therefore, it is critical to evaluate the NMJ formed by SMA patientsM-bM-^@M-^Y motor neurons (MNs), and to identify drugs that can restore the normal condition. We generated NMJ-like structures using motor neurons (MNs) derived from SMA patient-specific induced pluripotent stem cells (iPSCs), and found that the clustering of the acetylcholine receptor (AChR) is significantly impaired. Valproic acid and antisense oligonucleotide treatment ameliorated the AChR clustering defects, leading to an increase in the level of full-length SMN transcripts. Thus, the current in vitro model of AChR clustering using SMA patient-derived iPSCs is useful to dissect the pathophysiological mechanisms underlying the development of SMA, and to evaluate the efficacy of new therapeutic approaches.M-bM-^@M-^C To compare the gene expression pattern between control and patient derived iPSCs
Project description:Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations of the survival of motor neuron 1 (SMN1) gene. In the pathogenesis of SMA, pathological changes of the neuromuscular junction (NMJ) precede the motor neuronal loss. Therefore, it is critical to evaluate the NMJ formed by SMA patientsM-bM-^@M-^Y motor neurons (MNs), and to identify drugs that can restore the normal condition. We generated NMJ-like structures using motor neurons (MNs) derived from SMA patient-specific induced pluripotent stem cells (iPSCs), and found that the clustering of the acetylcholine receptor (AChR) is significantly impaired. Valproic acid and antisense oligonucleotide treatment ameliorated the AChR clustering defects, leading to an increase in the level of full-length SMN transcripts. Thus, the current in vitro model of AChR clustering using SMA patient-derived iPSCs is useful to dissect the pathophysiological mechanisms underlying the development of SMA, and to evaluate the efficacy of new therapeutic approaches.M-bM-^@M-^C to evaluate the effects of VPA on the expression profiles of the MNs
Project description:Spinal muscular atrophy (SMA) is a neuromuscular disease caused by mutations in the survival of motor neuron (SMN) gene. Although the primary manifestation of SMA is degeneration of motor neurons in a dying-back manner, deficient SMN intrinsic to motor neurons does not cause severe motor neuron loss, as is the case in SMA mouse models. Thus, the involvement of non-neuronal cells in the pathogenesis of SMA has been suggested. Here, we report that a novel subset of fibro-adipogenic progenitors expressing Dpp4 (Dpp4+ FAPs) is required for the survival of motor neurons, in which BRCA1-associating protein 1 (Bap1) is crucial for the stabilization of SMN by preventing its ubiquitination-dependent degradation. Inactivation of Bap1 in FAPs decreased SMN levels and accompanied degeneration of the neuromuscular junction, leading to dying-back loss of motor neurons and muscle atrophy, reminiscent of SMA pathogenesis. Overexpression of ubiquitination-resistant SMN variant, SMNK186R, in Bap1-null FAPs completely prevented neuromuscular degenerations. In addition, transplantation of Dpp4+ FAPs, but not Dpp4- FAPs, completely rescued neuromuscular defects in the mutant mice. Our data revealed that Bap1-mediated stabilization of SMN in Dpp4+ FAPs is crucial for the survival of motor neurons and provided a new therapeutic approach to treat SMA.
Project description:The neuromuscular junction (NMJ) is a specialized synapse that allows for the communication between spinal motor neurons and muscle fibers. Maintenance of motor-muscle connectivity at the NMJ is critical for the preservation of muscle strength and coordinated motor function. Unlike injuries that damage the central nervous system, motor neurons can mount a robust regenerative response after peripheral nerve injuries. In contrast, motor neurons selectively degenerate in diseases such as amyotrophic lateral sclerosis (ALS), which leads to progressive muscle wasting and paralysis. To assess how different insults affect motor neurons in vivo, we adapted the RiboTag methodology developed by Sanz et al. to perform ribosomal profiling of mouse motor neurons. Using this strategy we isolated and sequenced motor neuron-specific transcripts from spinal cord tissue following sciatic nerve crush, a model of acute injury and regeneration, and in the SOD1-G93A mouse model of ALS.
Project description:To profile the local translatome at the neuromuscular junction during various developmental stages We conducted RNA sequencing of synapse-enriched regions in the mouse diaphragms of both cre- and cre+ mice to investigate the local translatome at motor neuron terminals
Project description:Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations of the survival of motor neuron 1 (SMN1) gene. In the pathogenesis of SMA, pathological changes of the neuromuscular junction (NMJ) precede the motor neuronal loss. Therefore, it is critical to evaluate the NMJ formed by SMA patients’ motor neurons (MNs), and to identify drugs that can restore the normal condition. We generated NMJ-like structures using motor neurons (MNs) derived from SMA patient-specific induced pluripotent stem cells (iPSCs), and found that the clustering of the acetylcholine receptor (AChR) is significantly impaired. Valproic acid and antisense oligonucleotide treatment ameliorated the AChR clustering defects, leading to an increase in the level of full-length SMN transcripts. Thus, the current in vitro model of AChR clustering using SMA patient-derived iPSCs is useful to dissect the pathophysiological mechanisms underlying the development of SMA, and to evaluate the efficacy of new therapeutic approaches.