Differential gene expression in Drosophila larval brain due to mutation in the Beadex gene
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE197058 | GEO | 2023/02/20
REPOSITORIES: GEO
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Project description:To develop effective cures for neuromuscular diseases, human-relevant in vitro models of neuromuscular tissues are critically needed to probe disease mechanisms on the cellular and molecular level. However, previous attempts to co-culture motor neurons and skeletal muscle have resulted in relatively immature neuromuscular junctions (NMJs). In this study, NMJs formed by human induced pluripotent stem cell (hiPSC)-derived motor neurons were improved by optimizing the maturity of the co-cultured muscle tissue. First, muscle tissues were engineered from the C2C12 mouse myoblast cell line, cryopreserved primary human myoblasts, and freshly isolated primary chick myoblasts on micromolded gelatin hydrogels. After three weeks, only chick muscle tissues remained stably adhered to hydrogels and exhibited progressive increases in myogenic index and stress generation, approaching values generated by native muscle tissue. After three weeks of co-culture with hiPSC-derived motor neurons, engineered chick muscle tissues formed NMJs with increasing co-localization of pre- and post-synaptic markers as well as increased frequency and magnitude of synaptic activity, surpassing structural and functional maturity of previous in vitro models. Engineered chick muscle tissues also demonstrated increased expression of genes related to sarcomere maturation and innervation over time, revealing new insights into the molecular pathways that likely contribute to enhanced NMJ formation. These approaches for engineering human-relevant neuromuscular tissues with relatively mature NMJs and interrogating their structure and function have many applications in neuromuscular disease modeling and drug development.
2021-07-13 | GSE172606 | GEO
Project description:Purpose: To examine and characterize the expression profile of genes expressed at the neuromuscular junctions (NMJs) of extraocular muscles (EOMs) in comparison to the NMJs of tibialis anterior muscle (TA). Methods: Adult rat rectus EOMs and TAs were dissected, flash-frozen, serially sectioned and stained for acetylcholinesterase to identify NMJs. Approximately 6000 NMJs for EOM (EOMsyn) and 6000 NMJs for TA (TAsyn) and equal amounts of NMJ-free fiber regions (EOMfib, TAfib) and underlying myonuclei were captured using laser capture microdissection (LCM). RNA was isolated, processed and used for microarray-based expression profiling. Profiles were generated for genes differentially expressed at synaptic and non-synaptic regions of TA (TAsyn vs TAfib) and EOM (EOMsyn vs EOMfib) using a false discovery rate (FDR) of 5% as well as an 'interaction list' revealing the most significantly differentially expressed genes at an FDR of 1%. We validated the profiles by real-time quantitative reverse transcription-polymerase chain reaction (qPCR). Results: The regional transcriptomes associated with NMJ of EOMs and TAs were identified. We found 275 genes that were preferentially expressed in EOMsyn and 230 known transcripts that were preferentially expressed in TAsyn; 288 of the transcripts were common to both synapses; these included well-known, evolutionarily conserved, synaptic markers (e.g. nicotinic Acetylcholine receptor (ACHR) alpha and epsilon subunits, nestin) as well as a large number of novel genes. Conclusion: Transcriptome level differences exist between EOM synaptic regions and TA synaptic regions. Our definition of the synaptic transcriptome provides insight into the mechanism of formation and functioning of the unique synapses of EOM and their differential involvement in diseases noted in the EOM allotype. Tissue preparation: A total of 4 rats were killed by CO2 inhalation. The bony orbit was removed from the skull and opened at the lamina cribrosa. The globe with the four recti EOMs still attached was carefully dissected from the bony orbit. The eyeball with muscles was placed on cryomolds, covered with OCT tissue embedding medium (Tissue-Tek: Sakura Finetek, Tokyo, Japan) and flash-frozen in isopentane, cooled in liquid nitrogen and stored at -80 degreeC. The tibialis anterior (TA) muscles of all rats were dissected and frozen in the same way. The EOM and TA were then cut transversely into 10 um sections using a Microm HM 500 cryostat (Zeiss, Oberkochen, Germany), mounted on PEN (poly-ethylene-naphthalene) Membrane Slides (Arcturus) and refrozen immediately. Unfixed sections were stored at -80 degreeC until needed. Section staining: Sections for LCM were stained for acetylcholinesterase based on the method of Karnowsky and Roots to visualize NMJ. Palm microdissection: The PALM MicroBeam System was used for microdissection and for catapulting isolated tissue into a microfuge cap containing 80 ul RLT-Lysis Buffer (Quiagen). Approximately 1000 NMJ and equal amount of non-synaptic regions were collected for each muscle.
2010-04-28 | E-GEOD-15737 | biostudies-arrayexpress
Project description:Purpose: To examine and characterize the expression profile of genes expressed at the neuromuscular junctions (NMJs) of extraocular muscles (EOMs) in comparison to the NMJs of tibialis anterior muscle (TA). Methods: Adult rat rectus EOMs and TAs were dissected, flash-frozen, serially sectioned and stained for acetylcholinesterase to identify NMJs. Approximately 6000 NMJs for EOM (EOMsyn) and 6000 NMJs for TA (TAsyn) and equal amounts of NMJ-free fiber regions (EOMfib, TAfib) and underlying myonuclei were captured using laser capture microdissection (LCM). RNA was isolated, processed and used for microarray-based expression profiling. Profiles were generated for genes differentially expressed at synaptic and non-synaptic regions of TA (TAsyn vs TAfib) and EOM (EOMsyn vs EOMfib) using a false discovery rate (FDR) of 5% as well as an “interaction list” revealing the most significantly differentially expressed genes at an FDR of 1%. We validated the profiles by real-time quantitative reverse transcription-polymerase chain reaction (qPCR). Results: The regional transcriptomes associated with NMJ of EOMs and TAs were identified. We found 275 genes that were preferentially expressed in EOMsyn and 230 known transcripts that were preferentially expressed in TAsyn; 288 of the transcripts were common to both synapses; these included well-known, evolutionarily conserved, synaptic markers (e.g. nicotinic Acetylcholine receptor (ACHR) alpha and epsilon subunits, nestin) as well as a large number of novel genes. Conclusion: Transcriptome level differences exist between EOM synaptic regions and TA synaptic regions. Our definition of the synaptic transcriptome provides insight into the mechanism of formation and functioning of the unique synapses of EOM and their differential involvement in diseases noted in the EOM allotype.
2010-04-16 | GSE15737 | GEO
Project description:Mislocalization of the predominantly nuclear RNA/DNA binding protein, TDP-43, occurs in motor neurons of ~95% of ALS patients, but the contribution of axonal TDP-43 to this fatal neurodegenerative disease is unclear. Here, we find TDP-43 accumulation in the axons of intra-muscular nerves from ALS patients, and in motor neurons and neuromuscular junctions(NMJs) of a mouse model with TDP-43 mislocalization. This leads to the formation of G3BP1- and TDP-43-positive RNA-granules in motor neuron axons, and to inhibition of local protein synthesis in axons and NMJs. Specifically, the axonal and synaptic levels of nuclear-encoded mitochondria proteins are reduced. Clearance of axonal TDP-43 restored local translation of the nuclear-encoded mitochondrial proteins and rescued TDP-43-derived axonal and NMJ toxicity. These findings suggest that targeting TDP-43 axonal gain of function may mediata therapeutic effect in ALS.
2021-11-04 | PXD021876 | Pride
Project description:It is widely accepted that long-term changes in synapse structure and function are mediated by rapid activity-dependent gene transcription and new protein synthesis. A growing amount of evidence suggests that the microRNA (miRNA) pathway plays an important role in coordinating these processes. Despite recent advances in this field, there remains a critical need to identify specific activity-regulated miRNAs as well as their key messenger RNA (mRNA) targets. To address these questions, we used the larval Drosophila melanogaster neuromuscular junction (NMJ) as a model synapse in which to identify novel miRNA-mediated mechanisms that control activity-dependent synaptic growth. First, we developed a screen to identify miRNAs differentially regulated in the larval CNS following spaced synaptic stimulation. Surprisingly, we identified five miRNAs (miRs-1, -8, -289, -314, and -958) that were significantly downregulated by activity. Neuronal misexpression of three miRNAs (miRs-8, -289, and -958) suppressed activity-dependent synaptic growth suggesting that these miRNAs control the translation of biologically relevant target mRNAs. Functional annotation cluster analysis revealed that putative targets of miRs-8 and -289 are significantly enriched in clusters involved in the control of neuronal processes including axon development, pathfinding, and growth. In support of this, miR-8 regulated the expression of a wingless 3M-bM-^@M-^YUTR (wg 3M-bM-^@M-^Y untranslated region) reporter in vitro. Wg is an important presynaptic regulatory protein required for activity-dependent axon terminal growth at the fly NMJ. In conclusion, our results are consistent with a model where key activity-regulated miRNAs are required to coordinate the expression of genes involved in activity-dependent synaptogenesis. larval CNS of UAS-ChR2 x C380-Gal4 following synaptic stimulation
2013-02-01 | E-GEOD-43943 | biostudies-arrayexpress
Project description:Non-neuronal cells, including astrocytes, play a crucial role in the selective motor neuron pathology in amyotrophic lateral sclerosis (ALS). How astrocytes exactly contribute to the disease is not fully elucidated. Therefore, we characterised human induced pluripotent stem cell (hiPSC)-derived astrocytes from FUS-ALS patients, and incorporated these astrocytes into a human motor unit model to investigate the astrocytic effect on hiPSC-derived motor neuron network and neuromuscular junctions (NMJs). We observed a dysregulation of astrocyte homeostasis, which resulted in a FUS-ALS-mediated increase in reactivity and secretion of pro-inflammatory cytokines. Upon coculture with motor neurons and myotubes, we detected a cytotoxic effect on motor neuron-neurite morphology and outgrowth, as well as on NMJ formation and functionality, which was improved or fully rescued by isogenic control astrocytes. We conclude that mutant astrocytes have both a gain-of-toxicity and loss-of-support function in ALS, ultimately contributing to the disruption of motor neuron homeostasis, intercellular networks and NMJs.
2023-01-19 | GSE196219 | GEO
Project description:Desmin, the major intermediate filament (IF) protein in muscle cells, interlinks neighboring myofibrils and connects the whole myofibrillar apparatus to myonuclei, mitochondria, and the sarcolemma. However, desmin is also known to be enriched at postsynaptic membranes of neuromuscular junctions (NMJs). The pivotal role of the desmin IF cytoskeletal network is underscored by the fact that over 100 mutations of the human DES gene cause hereditary and sporadic myopathies and cardiomyopathies. A subgroup of human desminopathies comprises autosomal recessive cases resulting in complete abolition of desmin protein. In these patients, who display a more severe phenotype than the autosomal dominant cases, it has been reported that some individuals also suffer from a myasthenic syndrome in addition to the classical occurrence of myopathy and cardiomyopathy. Since further studies on the NMJ pathology is hampered by the lack of available human striated muscle biopsy specimens, we exploited homozygous desmin knock-out mice which closely mirror the striated muscle pathology of human patients lacking desmin protein. Here, we report on the impact of the lack of desmin on the structure and function of NMJs and on the transcription of genes coding for postsynaptic proteins. Desmin knock-out mice display a fragmentation of NMJs in soleus, but not in extensor digitorum longus muscle. Moreover, soleus muscle fibers show larger NMJs. Further, transcription levels of acetylcholine receptor (AChR) genes are increased in muscles from desmin knock-out mice, especially of the AChR subunit, which is known as a marker of muscle fiber regeneration. Electrophysiological recordings depicted a pathological decrement of nerve-dependent endplate potentials and a faster rise time of the nerve-independent miniature endplate potentials. The latter is indicating an enhanced opening time of the AChR channels. Our study highlights the essential role of desmin for the structural and functional integrity of mammalian neuromuscular junctions.
2020-07-17 | GSE154573 | GEO
Project description:The RNA from NMJ and non-NMJs samples were examined using microarray analysis with of identifying novel regulatory genes that are preferentially expressed in the synaptic regions of the isolated muscle fibers.
2019-12-12 | GSE92400 | GEO
Project description:We utilized genetic methods to examine how Schwann cells prevent degeneration of motor neurons (MNs) in the spinal cord. Blocking peripheral, neuromuscular activity completely rescued MNs and neuromuscular junctions (NMJs) in erbB3 mutant mice lacking Schwann cells, which normally exhibit profound neurodegeneration. We searched for the molecular basis of this effect by examining the transcriptomes (all of the expressed genes) in the muscle of control mice with Schwann cells and erbB3 mutant mice without them. We found evidence that a negative signal expressed by muscle was regulated by neural activity and normally blocked by factors produced in Schwann cells. When we eliminated this activity-induced negative signal (thrombin) from muscle, MNs and NMJs were protected in erbB3 mutants, similar to the effects of eliminating activity. Together, these results suggest that Schwann cells prevent neurodegeneration by inhibiting the effect of activity-induced, muscle-derived negative factors, rather than by providing trophic positive factors.
2019-03-14 | GSE125490 | GEO
Project description:It is widely accepted that long-term changes in synapse structure and function are mediated by rapid activity-dependent gene transcription and new protein synthesis. A growing amount of evidence suggests that the microRNA (miRNA) pathway plays an important role in coordinating these processes. Despite recent advances in this field, there remains a critical need to identify specific activity-regulated miRNAs as well as their key messenger RNA (mRNA) targets. To address these questions, we used the larval Drosophila melanogaster neuromuscular junction (NMJ) as a model synapse in which to identify novel miRNA-mediated mechanisms that control activity-dependent synaptic growth. First, we developed a screen to identify miRNAs differentially regulated in the larval CNS following spaced synaptic stimulation. Surprisingly, we identified five miRNAs (miRs-1, -8, -289, -314, and -958) that were significantly downregulated by activity. Neuronal misexpression of three miRNAs (miRs-8, -289, and -958) suppressed activity-dependent synaptic growth suggesting that these miRNAs control the translation of biologically relevant target mRNAs. Functional annotation cluster analysis revealed that putative targets of miRs-8 and -289 are significantly enriched in clusters involved in the control of neuronal processes including axon development, pathfinding, and growth. In support of this, miR-8 regulated the expression of a wingless 3M-bM-^@M-^YUTR (wg 3M-bM-^@M-^Y untranslated region) reporter in vitro. Wg is an important presynaptic regulatory protein required for activity-dependent axon terminal growth at the fly NMJ. In conclusion, our results are consistent with a model where key activity-regulated miRNAs are required to coordinate the expression of genes involved in activity-dependent synaptogenesis. Three technical replicates (each in raw data) of three biological replicates of wild-type (CantonS) larvae in two treatment groups: (1) 5x spaced high K; (2) or 0x mock stimulation.
2013-02-01 | E-GEOD-43944 | biostudies-arrayexpress