Direct genesis of functional rodent and human Schwann cells from skin mesenchymal precursors (rat)
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ABSTRACT: 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.
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 4 independent samples of neonatal human foreskin and 4 independent samples of discarded facial skin tissue from children less than two years old. Primary cells were isolated and cultured as SKPs and RNA was collected from those cultured samples. RNA samples deriving from these cells were analyzed on the Affymetrix Human Gene 2.0 ST Array.
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.
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.
Project description:The sympathetic nervous system controls a wide spectrum of bodily functions including operation of vessels, cardiac rhythm, and the “flight or fight response”. Sympathetic neurons, which are neural crest-derived, develop in coordination with presynaptic motor nerves extending from the central nervous system (CNS). By using nerve-selective genetic ablations, we revealed that sympathetic ganglia development depends on CNS-derived motor innervation. In the absence of preganglionic motor nerves, trunk sympathetic chain ganglia were fragmented and smaller in size, while cervical ganglia were severely misshapen. Sympathetic neurons were misplaced along sensory fibers and projected towards abnormal paths, in some cases invading the sensory dorsal root ganglia. The misplaced progenitors of sympathoblasts corresponded to the nerve-associated, neural crest-derived Schwann cell precursors (SCPs). Notably, we found that SCPs activate the autonomic marker PHOX2B while migrating along motor nerves towards the region of the dorsal aorta in wildtype embryos, suggesting that SCP differentiate into sympathetic neurons while still nerve-associated in motor-ablated embryos. Ligand-receptor prediction from single cell transcriptomic data coupled with functional studies identified Semaphorin 3A/3F as candidate motor nerve-derived signals influencing neural crest migration along axons. Thus, motor nerves control the placement of sympathoblasts and their subsequent axonal navigation during critical periods of sympathetic chain development.
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.
Project description:Schwann cell precursors (SCPs) are nerve-associated progenitors that not only can generate myelinating and non-myelinating Schwann cells but also are multipotent like the neural crest cells from which they originate. SCPs are omnipresent along outgrowing peripheral nerves throughout the body of vertebrate embryos. By using single-cell transcriptomics to generate the atlas of the entire neural crest lineage, we show that early SCPs and late migratory crest have similar transcriptional profiles characterized by a multipotent “hub” state containing cells biased towards traditional neural crest fates. SCPs keep diverging from the neural crest after being primed towards terminal Schwann cell and other fates, with different subtypes residing in distinct anatomical locations. Functional experiments using CRISPR-Cas9 loss-of-function further show that knock-out of the hub gene Sox8 causes defects in neural crest-derived cells along peripheral nerves by facilitating differentiation of SCPs towards sympathoadrenal fates. Finally, specific tumour populations found in melanoma, neurofibroma and neuroblastoma map to different stages of SCP/Schwann cell development. Overall, SCPs resemble migrating neural crest cells that maintain multipotency and become transcriptionally primed toward distinct lineages.
Project description:Understanding biological pathways critical for common neurofibromatosis type 1 (NF1) peripheral nerve tumors is essential, as tumor biomarkers, prognostic factors and therapeutics are all lacking. We used gene expression profiling to define transcriptional changes between primary normal Schwann cells (n = 10), NF1-derived primary benign neurofibroma Schwann cells (n = 22), malignant peripheral nerve sheath tumor (MPNST) cell lines (n = 13), benign neurofibromas (n = 26) and MPNST (n = 6). Dermal and plexiform neurofibromas were indistinguishable. A prominent theme in the analysis was aberrant differentiation. Neurofibromas repressed gene programs normally active in Schwann cell precursors and immature Schwann cells. MPNST signatures strongly differed; genes upregulated in the sarcomas were significantly enriched for genes activated in neural crest cells. We validated differential expression of 82 genes including the neural crest transcription factor SOX9 and SOX9 predicted targets. SOX9 immunoreactivity was robust in neurofibroma and MPSNT tissue sections and targeting SOX9 - strongly expressed in NF1-related tumors - caused MPNST cell death. SOX9 is a biomarker of neurofibroma and MPNST, and possibly a therapeutic target in NF1. Keywords: tumor stage 86 microarrays, consisting of 77 samples and 9 batch reference samples: NHSC (10), dNFSC (11), pNFSC (11), MPNST cell lines (13), dNF (13), pNF (13), MPNST (6)
Project description:The current understanding is that Schwann cell transplantation is ideal strategy for peripheral nerve regeneration instead of autograft. It is difficult to obtain the required amount of Schwann cells which are best transplant condition, and central nervous cells have been gained attention in recent years, but its regenerative mechanism remain unknown. Neural stem/progenitor cells (NSPC) can generate various type of neural lineage cells (NLCs), and NSPCs derived from pluripotent stem cells are promising cells for cell therapy for neurodegenerative diseases. However, more safe and accessible cell source of NSPCs are required. In this study, we aim to provide NLCs derived from human dental pulp stem cells (DPSCs), and reveal the mechanism involved in regeneration after NLCs transplantation into peripheral nerve defect. Here, characterization of NLCs, paracrine effects for endothelial cells and Schwann cells, in xenotransplant for rat 10mm sciatic nerve defect, the differentiation, the survival, and outcome of nerve regeneration were investigated. Induced NLCs consisted of neuronal lineage cells, astrocyte lineage cells, oligodendrocyte lineage cells, and neural crest lineage cells. Considering retrospectively, NLCs were possible derived from NSPCs. Microarray analysis revealed neural markers of primary embryological development were up-regulated in induced NLCs compared to DPSCs. Moreover, NLCs enhanced the activity of endothelial cells and Schwann cells by paracrine effects in vitro. Two weeks after transplantation, many transplanted NLCs differentiated into platelet-derived growth factor receptor alpha (PDGFRa) + oligodendrocyte progenitor cells (OPCs), and PDGFRa+/p75 neurotrophin receptor + Schwann cells derived from OPCs were observed. Twelve weeks after transplantation, NLCs promoted functional repair of peripheral nerve. A few human Schwann cells survived, but did not myelinate axon. These findings suggest that some of mechanism promoting for peripheral nerve regeneration by transplanted NLCs. Transplantation of NLCs derived from DPSCs into partial peripheral nerve defect may be widely used for further experiments.
Project description:Skin-derived precursors (SKPs) are multipotent dermal stem cells that reside within a hair follicle niche and that share properties with embryonic neural crest precursors. Here, we have asked whether SKPs and their endogenous dermal precursors originate from the neural crest or whether, like the dermis itself, they originate from multiple developmental origins. To do this, we used two different mouse Cre lines that allow us to perform lineage tracing: Wnt1-cre, which targets cells deriving from the neural crest, and Myf5-cre, which targets cells of a somite origin. By crossing these Cre lines to reporter mice, we show that the endogenous follicle-associated dermal precursors in the face derive from the neural crest, and those in the dorsal trunk derive from the somites, as do the SKPs they generate. In spite of these different developmental origins, SKPs from these two locations are functionally similar, even with regard to their ability to differentiate into Schwann cells, a cell type only thought to be generated from the neural crest. Analysis of global gene expression using microarrays confirmed that facial and dorsal SKPs exhibit a very high degree of similarity, and that they are also very similar to SKPs derived from ventral dermis, which has a lateral plate origin. However, these developmentally-distinct SKPs also retain differential expression of a small number of genes that reflect their developmental origins. Thus, an adult neural crest-like dermal precursor can be generated from a non-neural crest origin, a finding with broad implications for the many neuroendocrine cells in the body. We obtained three independent isolates each of dorsal trunk SKPs, ventral trunk SKPs and facial SKPs and four isolates of MSCs, all generated from adult rats. RNA samples deriving from these cells were analyzed on the Affymetrix GeneChip Rat Gene 1.0 ST Array.
Project description:Neural stem cells (NSCs) are most commonly sourced from neural tissue such as the central nervous system or the enteric nervous system (ENS) of the gut. Emerging evidence has shown that adipose tissue contains its own complex nervous system consisting of sympathetic and sensory innervation. The entirety of the peripheral nervous system is the progeny of Wnt1-expressing cells of the embryonic neural crest. This includes the ENS, autonomic neurons, and Schwann cell precursors that provide peripheral glial cells. Counterintuitive to their name, however, embryonic Schwann cell precursors represent multipotent stem cells that migrate along embryonic nerve fibers and contribute to glial and non-glial cell populations, including melanocytes, neuroendocrine chromaffin cells, enteric neurons, sympathetic neurons and mesenchymal stem cells from the bone marrow, depending on local environmental cues. However, no equivalent progenitors are known to exist postnatally in the nerve fiber niche. Schwann cells have been demonstrated to give rise to enteric neurons postnatally, suggesting they retain neuronal progenitor properties and offer a potential source of NSCs for regenerative therapies. In this study, we compare the transcriptomic properties of neural crest-derived NSCs from the intestine (enteric neural progenitors) and the nerve fibers of the subcutaneous adipose tissue and evaluate the effects of different methods of NSC culture and isolation.