Analysis of gene expression during neurite outgrowth and regeneration (MG-U74A)
Ontology highlight
ABSTRACT: We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Keywords: time course
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Keywords: time course
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Keywords: time course & treatment
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Experiment Overall Design: We wished to determine the transcriptional profiles of neurons undergoing neurite outgrowth in vitro. We were particularly interested in finding genes whose expression is generally associated with the process of neurite outgrowth, rather than with cell type-specific effects. Thus, in order to avoid focusing on transcripts unique to one tissue type versus another, we used a comparative strategy to look for effects that were common to two tissue types and therefore more likely to be involved in the general process of neurite outgrowth. While these explants contain multiple cell types, we felt this was preferable to the more disruptive conditions required to dissociate neurons or obtain a pure neuron population. To this end, we monitored gene expression in cultured explants from SCG and DRG using DNA microarrays. We initiated our studies by culturing embryonic day 13 (E13) mouse SCG in vitro and harvesting tissue for RNA isolation at time points from 2 to 65 hours. Time points were selected to detect both fast, short-term responses (2, 5 and 12 hours), as well as sustained, long-term changes (24, 40, and 65 hours). Samples were hybridized to Affymetrix MG-U74v2 A and B microarrays, with RNA from acutely dissected explants serving as a baseline reference. We followed these experiments with a parallel analysis of a more heterogeneous tissue type, the DRG, which is more frequently used than SCG for in vivo studies of neurite regeneration. Cervical and upper thoracic DRG from E12 embryos were cultured with NGF (the same trophic support as in SCG cultures), harvested at time points from 2 to 40 hours, and hybridized to Affymetrix MOE 430A microarrays.
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Experiment Overall Design: We wished to determine the transcriptional profiles of neurons undergoing neurite outgrowth in vitro. We were particularly interested in finding genes whose expression is generally associated with the process of neurite outgrowth, rather than with cell type-specific effects. Thus, in order to avoid focusing on transcripts unique to one tissue type versus another, we used a comparative strategy to look for effects that were common to two tissue types and therefore more likely to be involved in the general process of neurite outgrowth. While these explants contain multiple cell types, we felt this was preferable to the more disruptive conditions required to dissociate neurons or obtain a pure neuron population. To this end, we monitored gene expression in cultured explants from SCG and DRG using DNA microarrays. We initiated our studies by culturing embryonic day 13 (E13) mouse SCG in vitro and harvesting tissue for RNA isolation at time points from 2 to 65 hours. Time points were selected to detect both fast, short-term responses (2, 5 and 12 hours), as well as sustained, long-term changes (24, 40, and 65 hours). Samples were hybridized to Affymetrix MG-U74v2 A and B microarrays, with RNA from acutely dissected explants serving as a baseline reference. We followed these experiments with a parallel analysis of a more heterogeneous tissue type, the DRG, which is more frequently used than SCG for in vivo studies of neurite regeneration. Cervical and upper thoracic DRG from E12 embryos were cultured with NGF (the same trophic support as in SCG cultures), harvested at time points from 2 to 40 hours, and hybridized to Affymetrix MOE 430A microarrays.
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Experiment Overall Design: We wished to determine the transcriptional profiles of neurons undergoing neurite outgrowth in vitro. We were particularly interested in finding genes whose expression is generally associated with the process of neurite outgrowth, rather than with cell type-specific effects. Thus, in order to avoid focusing on transcripts unique to one tissue type versus another, we used a comparative strategy to look for effects that were common to two tissue types and therefore more likely to be involved in the general process of neurite outgrowth. While these explants contain multiple cell types, we felt this was preferable to the more disruptive conditions required to dissociate neurons or obtain a pure neuron population. To this end, we monitored gene expression in cultured explants from SCG and DRG using DNA microarrays. We initiated our studies by culturing embryonic day 13 (E13) mouse SCG in vitro and harvesting tissue for RNA isolation at time points from 2 to 65 hours. Time points were selected to detect both fast, short-term responses (2, 5 and 12 hours), as well as sustained, long-term changes (24, 40, and 65 hours). Samples were hybridized to Affymetrix MG-U74v2 A and B microarrays, with RNA from acutely dissected explants serving as a baseline reference. We followed these experiments with a parallel analysis of a more heterogeneous tissue type, the DRG, which is more frequently used than SCG for in vivo studies of neurite regeneration. Cervical and upper thoracic DRG from E12 embryos were cultured with NGF (the same trophic support as in SCG cultures), harvested at time points from 2 to 40 hours, and hybridized to Affymetrix MOE 430A microarrays.
Project description:Preconditioning nerve injury drives pro-regenerative perineuronal macrophage activation in dorsal root ganglia (DRG). The present study reports that oncomodulin (ONCM) is produced from the regeneration-associated macrophages (RAMs) and strongly influences regeneration of DRG sensory axons. ONCM in macrophages was necessary to produce RAMs in the in vitro model of neuron-macrophage interaction and played an essential role in for preconditioning-induced neurite outgrowth. In order to gain insight on potential mechanisms downstream of ONCM for potent neurite outgrowth activity, we performed RNA-seq using cultured DRG neurons treated with ONCM.
Project description:This SuperSeries is composed of the following subset Series:; GSE9738: Analysis of gene expression during neurite outgrowth and regeneration (430A and 420A 2.0 array); GSE9739: Analysis of gene expression during neurite outgrowth and regeneration (MG-U74A); GSE9740: Analysis of gene expression during neurite outgrowth and regeneration MG-U74B Experiment Overall Design: Refer to individual Series
Project description:Axon regeneration is a necessary step toward functional recovery after spinal cord injury. The AP-1 transcription factor c-Jun has long been known to play an important role in directing the transcriptional response of Dorsal Root Ganglion (DRG) neurons to peripheral axotomy that results in successful axon regeneration. Here we performed ChIPseq for Jun in mouse DRG neurons after a sciatic nerve crush or sham surgery in order to measure the changes in Jun’s DNA binding in response to peripheral axotomy. We found that the majority of Jun’s injury-responsive changes in DNA binding occur at putative enhancer elements, rather than proximal to transcription start sites. We also used a series of single polypeptide chain tandem transcription factors to test the effects of different Jun-containing dimers on neurite outgrowth in cortical and hippocampal neurons. These experiments demonstrated that dimers composed of Jun and Atf3 promoted neurite outgrowth in rat CNS neurons. Our work provides new insight into the mechanisms underlying Jun’s role in axon regeneration.
Project description:We screened nine genetically diverse inbred mouse strains for differences in axonal growth of adult dorsal root ganglion (DRG) neurons on CNS myelin. Naïve DRG neurite outgrowth on myelin was very limited, but preconditioning the neurons by a prior sciatic nerve crush increased axonal growth substantially across all strains, with by far the greatest change in neurons from CAST/Ei mice. Three independent in vivo CNS injury models revealed greater capacity for CNS axonal regeneration in CAST/Ei than C57BL/6 mice. Full-genome expression profiling of naïve and pre-conditioned DRGs across all strains revealed Activin-βA (Inhba) as the transcript whose expression most closely correlated with axonal growth on myelin. In vitro and in vivo gain- and loss-of-function experiments confirmed that Activin promotes axonal growth in the CNS. Substantial regeneration is possible, therefore, in the injured mammalian CNS when Activin signaling is intrinsically high, as in CAST/Ei or when extrinsically modulated in other strains. 9 strains, 4 replicates per strain, 2 conditions (naïve and axotomy) = 72 samples. 2 samples were excluded because technical outliers (AJ_AX5D_1 and AJ_NAIVE_4 excluded from the normalized data but included in the raw data)
Project description:Successful regeneration of injured neurons requires a complex molecular response that involves the expression, modification and transport of large numbers of proteins. The neuronal proteins responsible for the initiation of regenerative neurite outgrowth are largely unknown. Dorsal root ganglion (DRG) neurons display robust and successful regeneration following lesion of their peripheral neurite, whereas outgrowth of central neurites is weak and does not lead to functional recovery. We have utilized this differential response to gain insight in the early transcriptional events associated with successful regeneration. Surprisingly, our study shows that peripheral and central nerve crushes elicit very distinct transcriptional activation, revealing a large set of novel genes that are differentially regulated within the first 24 hours after the lesion. A large number of known regeneration associated genes were retrieved in our study, and, in addition, hundreds of novel genes possibly involved in the transcriptional regulatory network underlying successful regeneration. Please refer to Stam et al., Eur. J. Neurosci 25:3629 (2007). Keywords: time course