Transcription profiling of human Schwann cells after extended exposure to heregulin and forskolin
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Elizabeth Salomon
PROVIDER: E-GEOD-4030 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Schwann cells, expanded in number by exposure to growth factors in vitro, could be useful in nervous system repair. Our previous results suggest that long term exposure to heregulin and forskolin changes the functional properties of the human Schwann cells, including the ability to myelinate axons after transplantation. Here, we propose to determine the molecular changes in the Schwann cells that occur as a result of extended growth with mitogenic factors. We believe that the information obtained in these studies will provide clues about mechanisms underlying the already observed changes in function. This information will aid in the prediction of the safety and efficacy of neural repair approaches that use cultured, expanded Schwann cells. Finally this data may provide clues into the mechanisms underlying normal human Schwann cell function. To use gene array analysis to compare gene expression profiles in early and late passage human Schwann cells exposed to the growth factors heregulin and forskolin. Observed changes in the function of human Schwann cells, including their capacity for growth and differentiation, after prolonged exposure to heregulin and forskolin, are caused by changes in the gene expression profiles in these cells. Nerves from four different donors were obtained within 12-15 h postmortem, with full consent for research from the families of the donors (faxed). IRB approval not required because subjects were officially dead at nerve harvest (IRB confirmation faxed). The nerve tissue obtained consisted of the lower 15 cm of nerve extending from mid calf to ankle. Endoneurial fascicles were dissected from short (1-2 cm) nerve fragments and cultured with heregulin and forskolin for 1 week. The nerve fascicles were then treated overnight with collagenase and dispase and dissociated by gentle trituration. Cells were plated at low density on laminin coated dishes and maintained in culture with mitogens for 3 passages. Schwann cell purities during this period were > 95%. RNA was extracted from the cells at passage 1 ( i.e. after 2 population doublings) and passage 3 (i.e. after 8 population doublings) from the following donors: SN HSC 330, age 51; SN HSC 317, age 29; SN HSC 329, age 20 and SN HSC 351, age 42. Thus eight samples (2 groups, 4 independent samples per group) are to be analyzed. Because both groups in this comparison have been exposed to mitogens, differences in gene expression profiles will be interpreted as indicative of changes caused by prolonged versus short term exposure to mitogens. More RNA was prepared from each group of cells than was needed for gene array analysis to allow confirmation of differentially-expressed gene transcripts by real-time RT-PCR. Since the main purpose of this project is to detect any major changes in the molecular properties of the Schwann cells, we propose that these samples be analyzed using Affymetrix U133 + 2 arrays containing the complete human genome and request Option 1: Start to Finish Profiling of all samples. We have contacted Dr Stanley Nelson at UCLA and discussed the project with him. We request that the samples be analyzed in the UCLA facility. Keywords: time-course
2006-01-13 | GSE4030 | GEO
Project description:Aberrant DNA methylation (DNAm) was first linked to cancer over 25 years ago. Since then, many studies have associated hypermethylation of tumour suppressor genes and hypomethylation of oncogenes to the tumourigenic process. However, most of these studies have been limited to the analysis of promoters and CpG islands (CGIs). Recently, new technologies for whole-genome DNAm (methylome) analysis have been developed, enabling unbiased analysis of cancer methylomes. Using MeDIP-seq, we report a sequencing-based comparative methylome analysis of malignant peripheral nerve sheath tumours (MPNST), benign Neurofibromas and normal Schwann cells. Analysis of these methylomes revealed a complex landscape of DNAm alterations. Contrary to the current dogma, significant global hypomethylation was not observed in the MPNST methylome. However, a highly significant (P<10-100) directional difference in DNAm was found in satellite repeats, suggesting these repeats to be the main target for hypomethylation in MPNST. Comparative analysis of the MPNST and Schwann cell methylomes identified 101,466 cancer-associated differentially methylated regions (cDMRs). Analysis showed these cDMRs to be significantly enriched for two satellite repeat types (SATR1 and ARLM-NM-1) and suggests an association between aberrant DNAm of these sequences and transition from healthy cells to malignant disease. Significant enrichment of hypermethylated cDMRs in CGI shores (P<10-60), non-CGI-associated promoters (P<10-4) and hypomethylated cDMRs in SINE repeats (P<10-100) was also identified. Integration of DNAm and gene expression data showed that the expression pattern of genes associated with CGI shore cDMRs was able to discriminate between disease phenotypes. This study establishes MeDIP-seq as an effective method to analyse cancer methylomes. Examination of methylation profiles in malignant, benign and normal tissue
2011-01-01 | E-GEOD-21714 | biostudies-arrayexpress
Project description:Peripheral nerve repair and functional recovery depend on the rate of nerve regeneration and the quality of target reinnervation. It is important to fully understand the cellular and molecular basis underlying the specificity of peripheral nerve regeneration, which means the achieving of respective correct pathfinding and accurate target reinnervation for regrowing motor and sensory axons. In this study, a quantitative proteomic technique, based on isobaric tags for relative and absolute quantitation (iTRAQ) was used to profile the protein expression pattern between single motor and sensory nerves at 14 days after peripheral nerve transection. Among a total of 1259 proteins identified, 176 proteins showed the differential expressions between injured motor and sensory nerves. Quantitative real-time RT-PCR and Western blot analysis were applied to validate the proteomic data on representative differentially expressed proteins. Functional categorization indicated that differentially expressed proteins were linked to a diverse array of molecular functions, including axonogenesis, response to axon injury, tissue remodeling, axon ensheathment, cell proliferation and adhesion, vesicle-mediated transport, response to oxidative stress, internal signal cascade, and macromolecular complex assembly, which might play an essential role in peripheral motor and sensory nerve regeneration. Overall, we hope that the proteomic database obtained in this study could serve as a solid foundation for the comprehensive investigation of differentially expressed proteins between injured motor and sensory nerves and for the mechanism elucidation of the specificity of peripheral nerve regeneration.
2020-12-10 | PXD022097 | Pride
Project description:After nerve injury, myelin and Remak Schwann cells reprogram to repair cells specialized for regeneration. Normally providing strong regenerative support, these cells fail in aging animals, and during the chronic denervation that results from slow axon growth. This impairs axonal regeneration and causes a significant clinical problem. We find that aging and chronically denervated repair cells express reduced c-Jun protein and the regenerative support provided by these cells is also reduced. In both cases, genetically restoring Schwann cell c-Jun levels restores regeneration to that in controls. We identify potential gene candidates mediating this effect and implicate Shh in the control of Schwann cell c-Jun levels. These experiments reveal that a common mechanism, reduced c-Jun in repair cells, underlies two major reasons for regeneration failure in the PNS. They underscore the central importance of Schwann cell c-Jun as a regulator of nerve repair, and point to molecular pathways that can be manipulated for improving the clinical outcome of nerve injuries.
2020-10-14 | E-MTAB-9640 | biostudies-arrayexpress
Project description:The striking PNS regenerative response to injury rests on the plasticity of adult Schwann cells and their ability to transit between differentiation states, a highly unusual feature in mammals. Using mice with inactivation of Schwann cell c-Jun, we show that the injury response involves c-Jun dependent natural reprograming of differentiated cells to generate a distinct Schwann cell state specialized to promote regeneration. Transected distal stumps of c-Jun mutants show 172 disregulated genes, resulting in abnormal expression of growth factors, adhesion molecules and cytoskeletal changes that lead to neuronal death, inhibition of axon growth and striking failures of functional repair after injury. These observations provide a molecular basis for understanding Schwann cell plasticity and nerve regeneration. They offer conclusive support for the notion that Schwann cells control repair in the PNS, using dedicated transcriptional controls to generate a distinct repair cell, a transition that shows similarities to transdifferentiation seen in other systems. Total RNA was purified from a 10mm segment of the distal stump and uninjured contralateral nerve from c-Jun mutants and control mice 7 days after nerve cut. For each condition (injured/uninjured) and genotype (control/ knock-out) 2 independent samples (replicates) were generated from pooled nerves of 4/6 mice resulting in a total of 8 samples: CTRL.cut.R1, CTRL.cut.R2, CTRL.uncut.R1, CTRL.uncut.R2, KO.cut.R1, KO.cut.R2, KO.uncut.R1,KO.uncut.R2.
2012-06-13 | E-GEOD-38693 | biostudies-arrayexpress
Project description:The objective of this study was to compare the transcriptomes of uninfected and canine distemper virus-infected Schwann cells, olfactory ensheating cells, central nervous system Schwann cell-like glia, and fibroblasts cultured under identical conditions in vitro.
2014-06-02 | E-MTAB-2061 | biostudies-arrayexpress
Project description:- tryptic digests of CD34+ FAC-sorted cells dilution series acquired in DIA mode on Orbitrap Lumos - tryptic digests of HSC, MEP, GMP, CMP FAC-sorted cells acquired in DIA mode on Orbitrap Lumos
2019-04-25 | PXD009255 | Pride
Project description:Recent reports of directed reprogramming have raised questions about the stability of cell lineages. Here, we have addressed this issue, focusing upon skin-derived precursors (SKPs), a dermally-derived precursor cell. We show by lineage tracing that murine SKPs from dorsal skin originate from mesenchymal and not neural crest-derived cells. These mesenchymally-derived SKPs can, without genetic manipulation, generate functional Schwann cells, a neural crest cell type, and are highly similar at the transcriptional level to Schwann cells isolated from the peripheral nerve. This is not a mouse-specific phenomenon, since human SKPs that are highly similar at the transcriptome level can be made from facial (neural crest-derived) and foreskin (mesodermally-derived) dermis, and the mesodermally-derived SKPs can make myelinating Schwann cells. Thus, non-neural crest-derived mesenchymal precursors can differentiate into bona fide peripheral glia in the absence of genetic manipulation, suggesting that developmentally-defined lineage boundaries are more flexible than widely thought. We obtained 3 independent samples of nerve Schwann cells, SKP-derived Schwann cells, and Dorsal Trunk SKPs, each, from adult SD rats. Primary cells were isolated and cultured, and RNA was collected from those cultured samples. RNA samples deriving from these cells were analyzed on the Affymetrix Rat Gene 1.0 ST Array.
2014-08-01 | E-GEOD-57505 | biostudies-arrayexpress
Project description:Peripheral nerve injuries due to physical insults or chronic diseases are quite common, yet no pharmacological therapies are available for the effective repair of injured nerves. The slow growth rate of adult nerves and insufficient access to growth factors pose major hurdles in timely reinnervating target tissues and restoring functions after nerve injuries. A better understanding of the molecular changes that occur during the immediate regenerative reprogramming of neurons, stated here as in vivo priming, following nerve injury may reveal ideal candidates for future therapies. Hence, molecular profiling of neuronal soma within the first week of nerve injury has been the gold standard for revealing molecular candidates critical for nerve regeneration. A complementary in vitro regenerative priming approach was recently shown to induce enhanced outgrowth in adult sensory neurons. In this work, we exploited the in vitro priming model to reveal novel candidates for adult nerve regeneration. We performed the whole tissue proteomics analysis of in vitro primed DRGs and compared their molecular profile with that of the in vivo primed, and control DRGs. Through this approach, we identified several commonly and uniquely altered molecules in the in vitro and in vivo primed DRGs that have the potential to modulate adult nerve regrowth. We further validated the growth inducing potential of mesencephalic astrocyte-derived neurotrophic factor (MANF), one of the hits identified in our proteomics analysis, in primary adult sensory neurons. Overall, this study showed that in vitro priming partially reproduces the molecular features in in vivo primed adult sensory neurons. The shortlisted candidates presented here from the two priming approaches may serve as potential therapeutic targets for adult nerve regeneration.
2023-01-06 | PXD031927 | Pride
Project description:Objective: To investigate transplantation of rat Schwann cells or human iPSC-derived neural crest cells and derivatives into models of acquired and inherited peripheral myelin damage. Methods: Primary cultured rat Schwann cells labeled with a fluorescent protein for monitoring at various times after transplantation. Human induced pluripotent stem cells (iPSCs) were differentiated into neural crest stem cells (NCSC), and subsequently toward a Schwann cell lineage via two different protocols. Protocol 1 = treated with MesenPRO with Heregulin. Protocol 2 = coculture with iPSC-derived Motor Neurons. Cell types were characterized using flow cytometry, immunocytochemistry and transcriptomics. Rat Schwann cells and human iPSC-derivatives were transplanted into (i) nude rats pretreated with lysolecithin to induce demyelination or (ii) a transgenic rat model of dysmyelination due to PMP22 overexpression. Results: Rat Schwann cells transplanted into sciatic nerves with either toxic demyelination or genetic dysmyelination engrafted successfully, and migrated longitudinally for relatively long distances, with more limited axial migration. Transplanted Schwann cells engaged existing axons and displaced dysfunctional Schwann cells to form normal appearing myelin. Human iPSC-derived neural crest stem cells and their derivatives shared similar engraftment and migration characteristics to rat Schwann cells after transplantation, but did not further differentiate into Schwann cells or form myelin. Interpretation: These results indicate that cultured Schwann cells surgically delivered to peripheral nerve can engraft and form myelin in either acquired or inherited myelin injury, as proof of concept for pursuing cell therapy for diseases of peripheral nerve. However, lack of reliable technology for generating human iPSC-derived Schwann cells for transplantation therapy remains a barrier in the field.
2018-01-26 | GSE109686 | GEO