Control of peripheral glial cell proliferation: enteric neurons exert an inhibitory influence on Schwann cell and enteric glial cell DNA synthesis in culture

Development ◽  
1989 ◽  
Vol 107 (1) ◽  
pp. 107-112
Author(s):  
P.A. Eccleston ◽  
P.G. Bannerman ◽  
D.E. Pleasure ◽  
J. Winter ◽  
R. Mirsky ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Guinea Pig ◽  
Dna Synthesis ◽  
Glial Cell ◽  
Schwann Cells ◽  
Dorsal Root ◽  
Enteric Neurons ◽  
Synthesis Rate ◽  
Enteric Glia ◽  
Cell Numbers

Neuronal membranes from rat dorsal root ganglia provide a mitogenic signal to cultured Schwann cells and it has been suggested this is an important factor in regulating Schwann cell numbers during development. In this study, the influence of enteric neurons on the DNA synthesis of both Schwann cells and enteric glia has been investigated as well as the effect of axonal membrane fractions (axolemma) on enteric glia. The proliferation rate of rat Schwann cells and enteric glia was assessed in culture using [3H]thymidine uptake and autoradiography in combination with immunolabelling to identify cell types. When purified rat Schwann cells were co-cultured with guinea pig enteric neurons, their DNA synthesis rate was reduced compared with control cultures of pure Schwann cells or Schwann cells not close to neurites or neuronal cell bodies. Nevertheless, in accordance with previous findings that sensory neurons stimulate Schwann cell division, these Schwann cells increased their DNA synthesis rate when in contact with neurites from purified guinea pig or adult rat dorsal root ganglion neurons and on exposure to bovine axolemmal fractions. The enteric neurons also suppressed the DNA synthesis of enteric glia in co-cultures of purified enteric neurons and enteric glia, while bovine axolemma stimulated their DNA synthesis. These results indicate that a mitotic inhibitory signal is associated with enteric neurons and can exert its effect on both Schwann cells and enteric glia, and that enteric glia, like Schwann cells, are stimulated to divide by axolemmal fractions. It thus seems possible that during development glial cell numbers in the peripheral nervous system may be controlled by both positive and negative regulators of cell growth.

Spontaneous immortalisation of Schwann cells in culture: short-term cultured Schwann cells secrete growth inhibitory activity

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 33-42
Author(s):  
P.A. Eccleston ◽  
R. Mirsky ◽  
K.R. Jessen
Keyword(s):  
Growth Factor ◽  
Schwann Cell ◽  
Dna Synthesis ◽  
Schwann Cells ◽  
Inhibitory Activity ◽  
Short Term ◽  
Growth Inhibitory ◽  
Growth Inhibitory Activity ◽  
Cultured Schwann Cells

In the developing peripheral nerve, Schwann cells proliferate rapidly and then become quiescent, an essential step in control of Schwann cell differentiation. Cell proliferation is controlled by growth factors that can exert positive or inhibitory influences on DNA synthesis. It has been well established that neonatal Schwann cells divide very slowly in culture when separated from neurons but here we show that when culture was continued for several months some cells began to proliferate rapidly and non-clonal lines of immortalised Schwann cells were established which could be passaged for over two years. These cells had a similar molecular phenotype to short-term cultured Schwann cells, except that they expressed intracellular and cell surface fibronectin. The difference in proliferation rates between short- and long-term cultured Schwann cells appeared to be due in part to the secretion by short-term cultured Schwann cells of growth inhibitory activity since DNA synthesis of long-term, immortalised Schwann cells was inhibited by conditioned medium from short-term cultures. This conditioned medium also inhibited DNA synthesis in short-term Schwann cells stimulated to divide by glial growth factor or elevation of intracellular cAMP. The growth inhibitory activity was not detected in the medium of long-term immortalised Schwann cells, epineurial fibroblasts, a Schwannoma (33B), astrocytes or a fibroblast-like cell-line (3T3) and it did not inhibit serum-induced DNA synthesis in epineurial fibroblasts, 33B cells or 3T3 cells. The activity was apparently distinct from transforming growth factor-beta, activin, IL6, epidermal growth factor, atrial natriuretic peptide and gamma-interferon and was heat and acid stable, resistant to collagenase and destroyed by trypsin treatment. We raise the possibility that loss of an inhibitory autocrine loop may contribute to the rapid proliferation of long-term cultured Schwann cells and that an autocrine growth inhibitor may have a role in the cessation of Schwann cell division that precedes differentiation in peripheral nerve development.

Perspectives in Pain Research 2014: Neuroinflammation and glial cell activation: The cause of transition from acute to chronic pain?

2015 ◽  
Vol 6 (1) ◽  
pp. 3-6 ◽  
Author(s):  
Brian E. Cairns ◽  
Lars Arendt-Nielsen ◽  
Paola Sacerdote
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Dorsal Root Ganglion ◽  
Glial Cell ◽  
Schwann Cells ◽  
Glial Cells ◽  
Proinflammatory Cytokines ◽  
Immune Cells ◽  
Dorsal Root ◽  
Satellite Glial Cells

AbstractBackgroundIt is unknown why an acute pain condition under various circumstances can transition into a chronic pain condition.There has been a shift towards neuroinflammation and hence glial cell activations specifically in the dorsal root ganglion and spinal cord as a mechanism possibly driving the transition to chronic pain. This has led to a focus on non-neuronal cells in the peripheral and central nervous system. Besides infiltrating macrophages, Schwann cells and satellite glial cells release cytokines and therefore important mechanisms in the maintenance of pain. Activated Schwann cells, satellite glial cells, microglia, and astrocytes may contribute to pain sensitivity by releasing cytokines leading to altered neuronal function in the direction of sensitisation.Aims of this perspective paper1) Highlight the complex but important recent achievement in the area of neuroinflammation and pain at spinal cord level and in the dorsal root ganglion.2) Encourage further research which hopefully may provide better understanding of new key elements driving the transition from acute to chronic pain.Recent results in the area of neuroinflammation and painFollowing a sciatic nerve injury, local macrophages, and Schwann cells trigger an immune response immediately followed by recruitment of blood-derived immune cells. Schwann cells, active resident, and infiltrating macrophages release proinflammatory cytokines. Proinflammatory cytokines contribute to axonal damage and also stimulate spontaneous nociceptor activity. This results in activation of satellite glial cells leading to an immune response in the dorsal root ganglia driven by macrophages, lymphocytes and satellite cells. The anterograde signalling progresses centrally to activate spinal microglia with possible up regulation of glial-derived proinflammatory/pronociceptive mediators.An important aspect is extrasegmental spreading sensitisation where bilateral elevations in TNF-α, IL-6, and IL-10 are found in dorsal root ganglion in neuropathic models. Similarly in inflammatory pain models, bilateral up regulation occurs for TNF-α, IL-1 β, and p38 MAPK. Bilateral alterations in cytokine levels in the DRG and spinal cord may underlie the spread of pain to the uninjured side.An important aspect is how the opioids may interact with immune cells as opioid receptors are expressed by peripheral immune cells and thus can induce immune signaling changes. Furthermore, opioids may stimulate microglia cells to produce proinflammatory cytokines such as IL-1.ConclusionsThe present perspective paper indicates that neuroinflammation and the associated release of pro-inflammatory cytokines in dorsal root ganglion and at the spinal cord contribute to the transition from acute to chronic pain. Neuroinflammatory changes have not only been identified in the spinal cord and brainstem, but more recently, in the sensory ganglia and in the nerves as well. The glial cell activation may be responsible for contralateral spreading and possible widespread sensitisation.ImplicationsCommunication between glia and neurons is proposed to be a critical component of neuroinflammatory changes that may lead to chronic pain. Sensory ganglia neurons are surrounded by satellite glial cells but how communication between the cells contributes to altered pain sensitivity is still unknown. Better understanding may lead to new possibilities for (1) preventing development of chronic pain and (2) better pain management.

scholarly journals Transforming growth factors-beta 1 and beta 2 are mitogens for rat Schwann cells.

1989 ◽  
Vol 109 (6) ◽  
pp. 3419-3424 ◽  
Author(s):  
A J Ridley ◽  
J B Davis ◽  
P Stroobant ◽  
H Land
Keyword(s):  
Growth Factor ◽  
Schwann Cell ◽  
Dna Synthesis ◽  
Schwann Cells ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Tgf Beta ◽  
Beta 2 ◽  
Cell Mitogen ◽  
Stimulation Of

Transforming growth factor-beta 1 (TGF-beta 1) and TGF-beta 2 were found to be potent mitogens for purified rat Schwann cells, each stimulating DNA synthesis in quiescent cells and also increasing their proliferation rate. Half-maximal stimulation of DNA synthesis occurred at approximately 0.1 ng/ml TGF-beta 1 or TGF-beta 2. Mitogenic stimulation by TGF-beta 1 and TGF-beta 2 was enhanced by forskolin, which activates adenylate cyclase, at concentrations up to 0.5 microM forskolin. However, at 5 microM forskolin, the synergistic interaction between forskolin and TGF-beta 1 was abolished. These results are in contrast to the observed synergy between forskolin and another Schwann cell mitogen, glial growth factor (GGF). Both 0.5 and 5 microM forskolin were found to enhance the stimulation of DNA synthesis by partially purified GGF (GGF-CM). As well as being functionally distinct, TGF-beta 1 and GGF-CM activities were also physically separable by chromatography on a Superose 12 gel permeation column. Thus, TGF-beta 1 and beta 2 are rat Schwann cell mitogens, and Schwann cells are one of the few normal cell populations to respond mitogenically to TGF-beta.

scholarly journals Activation of Raf signalling in NF2-null Schwann cells leads to sustained proliferation; an investigation of a new and inducible model for human schwannoma

2021 ◽  
Vol 23 (Supplement_4) ◽  
pp. iv7-iv7
Author(s):  
Charlotte Lespade ◽  
Liyam Laraba ◽  
Evyn Woodhouse ◽  
Marie Srotyr ◽  
Alison C Lloyd ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Mouse Model ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Proliferation Response

Abstract Aims The NF2 gene encodes the tumour suppressor Merlin, which is deleted in 100% of patients with the familial tumour predisposition syndrome neurofibromatosis type 2 but also in 70% of those who develop sporadic schwannomas. The Raf-TR mouse model uses a tamoxifen-inducible Raf-kinase/ oestrogen receptor fusion protein (Raf-TR) expressed in myelinating Schwann cells to mimic a nerve injury response in Schwann cell by activating Raf/MEK/ERK signalling in the absence of peripheral nerve injury. We will assess whether Raf/MEK/ERK activation on an NF2 null background leads to tumourigenesis within the vestibular nerves and dorsal root ganglia (DRGs), two tumour sites identified in the Periostin-Cre mouse model in which schwannoma formation is spontaneous, with a view to generating an inducible NF2 null schwannoma mouse model. Method Mice with a Schwann cell specific loss of Merlin were crossed with mice carrying a tamoxifen-inducible Raf-TR gene to generate Raf-TR+/-; P0-Cre+/-; NF2fl/fl (Cre+) mice which were NF2 null and compared to Raf-TR+/-; P0-Cre-/-; NF2fl/fl (Cre-) littermate controls. Mice were injected with tamoxifen or vehicle for five consecutive days and their vestibular nerves and dorsal root ganglia (DRGs) were analysed at various timepoints . An EdU proliferation assay was used to quantify the proliferation in the vestibular ganglia, as well as the DRGs. Rates of proliferation were compared to Cre- age-matched littermate controls treated with tamoxifen or vehicle. Results In the Periostin-Cre NF2 null schwannoma model, tumours form spontaneously in the DRGs and vestibular ganglia. In our new model, we see a clear increase in proliferation at 21 d post-injection in the NF2 null (Cre+) tamoxifen-treated mice compared to control (Cre-) tamoxifen-treated controls in both DRGs and vestibular ganglia. Cre- tamoxifen-treated mice do not show increased proliferation compared to Cre- vehicle controls. Taken together, this shows that activation of the Raf/MEK/ERK pathway in Schwann cells only causes a sustained proliferation response on an NF2 null background in the DRGs and vestibular ganglia. We are assessing later timepoints to further characterise tumour development in these mice. Conclusion Combining the Raf-TR mouse model to create a demyelinating phenotype with an NF2 null background leads to vastly increased rates of proliferation at the sites of schwannoma tumourigenesis within the peripheral nervous system: the DRGs and the vestibular ganglia. The high proliferation in the vestibular ganglia in particular is similar to the development of vestibular schwannomas in patients with Neurofibromatosis type 2. The new mouse model used in this study shows potential to be very useful as an inducible schwannoma tumour model, in which we can study the early events of tumour formation.

scholarly journals Studies of adhesion molecules mediating interactions between cells of peripheral nervous system indicate a major role for L1 in mediating sensory neuron growth on Schwann cells in culture.

1988 ◽  
Vol 107 (1) ◽  
pp. 341-351 ◽  
Author(s):  
B Seilheimer ◽  
M Schachner
Keyword(s):  
Nervous System ◽  
Dorsal Root Ganglion ◽  
Schwann Cell ◽  
Neurite Outgrowth ◽  
Adhesion Molecules ◽  
Schwann Cells ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Ganglion Neurons ◽  
Large Neurons

The involvement of the adhesion molecules L1, N-CAM, and J1 in adhesion and neurite outgrowth in the peripheral nervous system was investigated. We prepared Schwann cells and fibroblasts (from sciatic nerves) and neurons (from dorsal root ganglia) from 1-d mice. These cells were allowed to interact with each other in a short-term adhesion assay. We also measured outgrowth of dorsal root ganglion neurons on Schwann cell and fibroblast monolayers. Schwann cells (which express L1, N-CAM, and J1) adhered most strongly to dorsal root ganglion neurons by an L1-dependent mechanism and less by N-CAM and J1. Schwann cell-Schwann cell adhesion was mediated by L1 and N-CAM, but not J1. Adhesion of fibroblasts (which express N-CAM, but not L1 or J1) to neurons or Schwann cells was mediated by L1 and N-CAM and not J1. However, inhibition by L1 and N-CAM antibodies was found to be less pronounced with fibroblasts than with Schwann cells. N-CAM was also strongly involved in fibroblast-fibroblast adhesion. Neurite outgrowth was most extensive on Schwann cells and less on fibroblasts. A difference in extent of neurite elongation was seen between small- (10-20 microns) and large- (20-35 microns) diameter neurons, with the larger neurons tending to exhibit longer neurites. Fab fragments of polyclonal L1, N-CAM, and J1 antibodies exerted slightly different inhibitory effects on neurite outgrowth, depending on whether the neurites were derived from small or large neurons. L1 antibodies interfered most strikingly with neurite outgrowth on Schwann cells (inhibition of 88% for small and 76% for large neurons), while no inhibition was detectable on fibroblasts. Similarly, although to a smaller extent than L1, N-CAM appeared to be involved in neurite outgrowth on Schwann cells and not on fibroblasts. Antibodies to J1 only showed a very small effect on neurite outgrowth of large neurons on Schwann cells. These observations show for the first time that identified adhesion molecules are potent mediators of glia-dependent neurite formation and attribute to L1 a predominant role in neurite outgrowth on Schwann cells which may be instrumental in regeneration.

Parasympathetic ganglia derive from Schwann cell precursors

Science ◽  
2014 ◽  
Vol 345 (6192) ◽  
pp. 87-90 ◽  
Author(s):  
I. Espinosa-Medina ◽  
E. Outin ◽  
C. A. Picard ◽  
Z. Chettouh ◽  
S. Dymecki ◽  
...  
Keyword(s):  
Nervous System ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Dorsal Root Ganglia ◽  
Cranial Nerve ◽  
Dorsal Root ◽  
Normal Development ◽  
Parasympathetic Ganglia ◽  
Parasympathetic Neurons ◽  
Schwann Cell Precursors

Neural crest cells migrate extensively and give rise to most of the peripheral nervous system, including sympathetic, parasympathetic, enteric, and dorsal root ganglia. We studied how parasympathetic ganglia form close to visceral organs and what their precursors are. We find that many cranial nerve-associated crest cells coexpress the pan-autonomic determinantPaired-like homeodomain 2b(Phox2b) together with markers of Schwann cell precursors. Some give rise to Schwann cells after down-regulation of PHOX2b. Others form parasympathetic ganglia after being guided to the site of ganglion formation by the nerves that carry preganglionic fibers, a parsimonious way of wiring the pathway. Thus, cranial Schwann cell precursors are the source of parasympathetic neurons during normal development.

scholarly journals A neuronal cell surface heparan sulfate proteoglycan is required for dorsal root ganglion neuron stimulation of Schwann cell proliferation.

1985 ◽  
Vol 101 (3) ◽  
pp. 744-754 ◽  
Author(s):  
N Ratner ◽  
R P Bunge ◽  
L Glaser
Keyword(s):  
Dorsal Root Ganglion ◽  
Schwann Cell ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Schwann Cells ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Sulfate Proteoglycan ◽  
Mitogenic Response ◽  
Ganglion Neurons

Axons of dorsal root ganglion neurons express on their surfaces one or more proteins which are mitogenic for Schwann cells (Salzer, J., R. P. Bunge, and L. Glaser, 1980, J. Cell Biol., 84:767-778). Incubation of co-cultures of dorsal root ganglion neurons and Schwann cells with 4-methylumbelliferyl-beta-D-xyloside, an inhibitor of proteoglycan biosynthesis, decreases the mitogenic response of the Schwann cell by over 95%. The effect of the beta-D-xyloside has been localized to the neurons; pretreatment of neurons but not of Schwann cells with the inhibitor causes a marked reduction of the mitogenic response. In addition, Schwann cells treated with beta-D-xyloside are still mitogenically responsive to soluble Schwann cell mitogens (cholera toxin and glial growth factor). Neurons treated with heparitinase and membrane vesicles prepared from heparitinase-treated neurons show diminished mitogenicity for Schwann cells, while other proteoglycan lyases have no effect. We conclude that a cell surface heparan sulfate proteoglycan is a component of the Schwann cell mitogen present on the surface of dorsal root ganglion neurons.

Changes in DNA Synthesis Rate in the Schwann Cell LineageIn VivoAre Correlated With the Precursor - Schwann Cell Transition and Myelination

1993 ◽  
Vol 5 (9) ◽  
pp. 1136-1144 ◽  
Author(s):  
Helen J. S. Stewart ◽  
Louise Morgan ◽  
Kristjan R. Jessen ◽  
Rhona Mirsky
Keyword(s):  
Schwann Cell ◽  
Dna Synthesis ◽  
Synthesis Rate ◽  
Cell Transition
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