Expression of cytokines and cytokine receptors in human Schwann cells

Lactobacillus Plantarum intake mitigates neuropathic pain behavior via enhancing macrophage M2 polarization in a rat model of peripheral neuropathy

Pro-inflammatory macrophages (M1-polarized) play a crucial role in neuroinflammation and neuropathic pain following nerve injury. Redirecting macrophage polarization toward anti-inflammatory (M2-polarized) phenotypes offers a promising therapeutic strategy. Recognized for their anti-inflammatory and immunomodulatory properties, probiotics are becoming a focal point of research. This study investigated the effects of Lactobacillus plantarum on macrophage polarization, nerve protection, and neuropathic pain behavior following chronic constriction injury (CCI) of the median nerve. Rats received daily oral doses of L. plantarum for 28 days before and 14 days after CCI. Subsequently, behavioral and electrophysiological assessments were performed. The M1 marker CD86 levels, M2 marker CD206 levels, and concentrations of pro-inflammatory and anti-inflammatory cytokines in the injured median nerve were assessed. L. plantarum administration effectively reduced neuropathic pain behavior and the Firmicutes to Bacteroidetes ratio after CCI. Moreover, L. plantarum treatment increased serum short-chain fatty acids (SCFAs) levels, preserved myelination of the injured median nerve, and suppressed injury-induced discharges. In CCI rats treated with L. plantarum, there was a reduction in CD86 and pro-inflammatory cytokine levels, accompanied by an increase in CD206 and the release of anti-inflammatory cytokines. Furthermore, receptors for anti-inflammatory cytokines were localized on Schwann cells, and their expression was significantly upregulated in the injured nerves of CCI rats receiving L. plantarum. In conclusion, L. plantarum shifts macrophage phenotypes from M1 to M2 by promoting the production of SCFAs and enhancing the release of anti-inflammatory cytokines. Ultimately, this process preserves nerve fiber integrity and impedes the onset of neuropathic pain.

A review about the role of additives in nerve tissue engineering: growth factors, vitamins, and drugs

Notably the integration of additives such as growth factors, vitamins, and drugs with scaffolds promoted nerve tissue engineering. This study tried to provide a concise review of all these additives that facilitates nerve regeneration. An attempt was first made to provide information on the main principle of nerve tissue engineering, and then to shed light on the effectiveness of these additives on nerve tissue engineering. Our research has shown that growth factors accelerate cell proliferation and survival, while vitamins play an effective role in cell signalling, differentiation, and tissue growth. They can also act as hormones, antioxidants, and mediators. Drugs also have an excellent and necessary effect on this process by reducing inflammation and immune responses. This review shows that growth factors were more effective than vitamins and drugs in nerve tissue engineering. Nevertheless, vitamins were the most commonly used additive in the production of nerve tissue.

Macrophages influence Schwann cell myelin autophagy after nerve injury and in a model of Charcot-Marie-Tooth disease

BACKGROUND AND AIMS

The complex cellular and molecular interactions between Schwann cells (SCs) and macrophages during Wallerian degeneration are a prerequisite to allow rapid uptake and degradation of myelin debris and axonal regeneration after peripheral nerve injury. In contrast, in non-injured nerves of Charcot-Marie-Tooth 1 neuropathies, aberrant macrophage activation by SCs carrying myelin gene defects is a disease amplifier that drives nerve damage and subsequent functional decline. Consequently, targeting nerve macrophages might be a translatable treatment strategy to mitigate disease outcome in CMT1 patients. Indeed, in previous approaches, macrophage targeting alleviated the axonopathy and promoted sprouting of damaged fibers. Surprisingly, this was still accompanied by robust myelinopathy in a model for CMT1X, suggesting additional cellular mechanisms of myelin degradation in mutant peripheral nerves. We here investigated the possibility of an increased SC-related myelin autophagy upon macrophage targeting in Cx32def mice.

METHODS

Combining ex vivo and in vivo approaches, macrophages were targeted by PLX5622 treatment. SC autophagy was investigated by immunohistochemical and electron microscopical techniques.

RESULTS

We demonstrate a robust upregulation of markers for SC autophagy after injury and in genetically-mediated neuropathy when nerve macrophages are pharmacologically depleted. Corroborating these findings, we provide ultrastructural evidence for increased SC myelin autophagy upon treatment in vivo.

INTERPRETATION

These findings reveal a novel communication and interaction between SCs and macrophages. This identification of alternative pathways of myelin degradation may have important implications for a better understanding of therapeutic mechanisms of pharmacological macrophage targeting in diseased peripheral nerves.

Schwann cell functions in peripheral nerve development and repair

The glial cell of the peripheral nervous system (PNS), the Schwann cell (SC), counts among the most multifaceted cells of the body. During development, SCs secure neuronal survival and participate in axonal path finding. Simultaneously, they orchestrate the architectural set up of the developing nerves, including the blood vessels and the endo-, peri- and epineurial layers. Perinatally, in rodents, SCs radially sort and subsequently myelinate individual axons larger than 1 μm in diameter, while small calibre axons become organised in non-myelinating Remak bundles. SCs have a vital role in maintaining axonal health throughout life and several specialized SC types perform essential functions at specific locations, such as terminal SC at the neuromuscular junction (NMJ) or SC within cutaneous sensory end organs. In addition, neural crest derived satellite glia maintain a tight communication with the soma of sensory, sympathetic, and parasympathetic neurons and neural crest derivatives are furthermore an indispensable part of the enteric nervous system. The remarkable plasticity of SCs becomes evident in the context of a nerve injury, where SC transdifferentiate into intriguing repair cells, which orchestrate a regenerative response that promotes nerve repair. Indeed, the multiple adaptations of SCs are captivating, but remain often ill-resolved on the molecular level. Here, we summarize and discuss the knowns and unknowns of the vast array of functions that this single cell type can cover in peripheral nervous system development, maintenance, and repair.

Human repair-related Schwann cells adopt functions of antigen-presenting cells in vitro

The plastic potential of Schwann cells (SCs) is increasingly recognized to play a role after nerve injury and in diseases of the peripheral nervous system. Reports on the interaction between immune cells and SCs indicate their involvement in inflammatory processes. However, the immunocompetence of human SCs has been primarily deduced from neuropathies, but whether after nerve injury SCs directly regulate an adaptive immune response is unknown. Here, we performed comprehensive analysis of immunomodulatory capacities of human repair-related SCs (hrSCs), which recapitulate SC response to nerve injury in vitro. We used our well-established culture model of primary hrSCs from human peripheral nerves and analyzed the transcriptome, secretome, and cell surface proteins for pathways and markers relevant in innate and adaptive immunity, performed phagocytosis assays, and monitored T-cell subset activation in allogeneic co-cultures. Our findings show that hrSCs are phagocytic, which is in line with high MHCII expression. Furthermore, hrSCs express co-regulatory proteins, such as CD40, CD80, B7H3, CD58, CD86, and HVEM, release a plethora of chemoattractants, matrix remodeling proteins and pro- as well as anti-inflammatory cytokines, and upregulate the T-cell inhibiting PD-L1 molecule upon pro-inflammatory stimulation with IFNγ. In contrast to monocytes, hrSC alone are not sufficient to trigger allogenic CD4+ and CD8+ T-cells, but limit number and activation status of exogenously activated T-cells. This study demonstrates that hrSCs possess features and functions typical for professional antigen-presenting cells in vitro, and suggest a new role of these cells as negative regulators of T-cell immunity during nerve regeneration.

Artificial nerve graft constructed by coculture of activated Schwann cells and human hair keratin for repair of peripheral nerve defects

Studies have shown that human hair keratin (HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1β to secrete nerve growth factor, which promotes neural regeneration. Therefore, HHK with Schwann cells may be a more effective approach to repair nerve defects than HHK without Schwann cells. In this study, we established an artificial nerve graft by loading an HHK skeleton with activated Schwann cells. We found that the longitudinal HHK microfilament structure provided adhesion medium, space and direction for Schwann cells, and promoted Schwann cell growth and nerve fiber regeneration. In addition, interleukin-1β not only activates Schwann cells, but also strengthens their activity and increases the expression of nerve growth factors. Activated Schwann cells activate macrophages, and activated macrophages secrete interleukin-1β, which maintains the activity of Schwann cells. Thus, a beneficial cycle forms and promotes nerve repair. Furthermore, our studies have found that the newly constructed artificial nerve graft promotes the improvements in nerve conduction function and motor function in rats with sciatic nerve injury, and increases the expression of nerve injury repair factors fibroblast growth factor 2 and human transforming growth factor B receptor 2. These findings suggest that this artificial nerve graft effectively repairs peripheral nerve injury.

Role of Transforming Growth Factor Beta in Peripheral Nerve Regeneration: Cellular and Molecular Mechanisms

Peripheral nerve injury (PNI) is one of the most common concerns in trauma patients. Despite significant advances in repair surgeries, the outcome can still be unsatisfactory, resulting in morbidities such as loss of sensory or motor function and reduced quality of life. This highlights the need for more supportive strategies for nerve regrowth and adequate recovery. Multifunctional cytokine transforming growth factor-β (TGF-β) is essential for the development of the nervous system and is known for its neuroprotective functions. Accumulating evidence indicates its involvement in multiple cellular and molecular responses that are critical to peripheral nerve repair. Following PNI, TGF-β is released at the site of injury where it can initiate a series of phenotypic changes in Schwann cells (SCs), modulate immune cells, activate neuronal intrinsic growth capacity, and regulate blood nerve barrier (BNB) permeability, thus enhancing the regeneration of the nerves. Notably, TGF-β has already been applied experimentally in the treatment of PNI. These treatments with encouraging outcomes further demonstrate its regeneration-promoting capacity. Herein, we review the possible roles of TGF-β in peripheral nerve regeneration and discuss the underlying mechanisms, thus providing new cues for better treatment of PNI.

Schwann Cells Accelerate Osteogenesis via the Mif/CD74/FOXO1 Signaling Pathway In Vitro

Schwann cells have been found to promote osteogenesis by an unclear molecular mechanism. To better understand how Schwann cells accelerate osteogenesis, RNA-Seq and LC-MS/MS were utilized to explore the transcriptomic and metabolic response of MC3T3-E1 to Schwann cells. Osteogenic differentiation was determined by ALP staining. Lentiviruses were constructed to alter the expression of Mif (macrophage migration inhibitory factor) in Schwann cells. Western blot (WB) analysis was employed to detect the protein expression. The results of this study show that Mif is essential for Schwann cells to promote osteogenesis, and its downstream CD74/FOXO1 is also involved in the promotion of Schwann cells on osteogenesis. Further, Schwann cells regulate amino acid metabolism and lipid metabolism in preosteoblasts. These findings unveil the mechanism for Schwann cells to promote osteogenesis where Mif is a key factor.

The Role of the IL-4 Signaling Pathway in Traumatic Nerve Injuries

Following traumatic peripheral nerve injury, adequate restoration of function remains an elusive clinical goal. Recent research highlights the complex role that the immune system plays in both nerve injury and regeneration. Pro-regenerative processes in wounded soft tissues appear to be significantly mediated by cytokines of the type 2 immune response, notably interleukin (IL)-4. While IL-4 signaling has been firmly established as a critical element in general tissue regeneration during wound healing, it has also emerged as a critical process in nerve injury and regeneration. In this context of peripheral nerve injury, endogenous IL-4 signaling has recently been confirmed to influence more than leukocytes, but including also neurons, axons, and Schwann cells. Given the role IL-4 plays in nerve injury and regeneration, exogenous IL-4 and/or compounds targeting this signaling pathway have shown encouraging preliminary results to treat nerve injury or other neuropathy in rodent models. In particular, the exogenous stimulation of the IL-4 signaling pathway appears to promote postinjury neuron survival, axonal regeneration, remyelination, and thereby improved functional recovery. These preclinical data strongly suggest that targeting IL-4 signaling pathways is a promising translational therapy to augment treatment approaches of traumatic nerve injury. However, a better understanding of the type 2 immune response and associated signaling networks functioning within the nerve injury microenvironment is still needed to fully develop this promising therapeutic avenue.

Angiogenesis and nerve regeneration induced by local administration of plasmid pBud-coVEGF165-coFGF2 into the intact rat sciatic nerve

Vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) are well-known growth factors involved in the regeneration of various tissues and organs, including peripheral nerve system. In the present study, we elucidated the local and systemic effects of plasmid construct рBud-coVEGF165-coFGF2 injected into the epineurium of intact rat sciatic nerve. Results of histological examination of sciatic nerve and multiplex immunoassays of serum showed the absence of immunogenicity and biosafety of plasmid рBud-coVEGF165-coFGF2. Moreover, local administration of plasmid DNA construct resulted in significantly decreased levels of pro-inflammatory cytokines in the peripheral blood, including tumor necrosis factor α (TNFα) and interleukin-12, and significantly increased levels of cytokines and chemokines including Regulated upon Activation, Normal T Cell Expressed and Presumably Secrete (RANTES), epidermal growth factor, interleukin-2, and monocyte chemoattractant protein 1. These changes in the peripheral blood on day 7 after injection of plasmid construct рBud-coVEGF165-coFGF2 show that the plasmid construct has systemic effects and may modulate immune response. At the same time, reverse transcription-polymerase chain reaction revealed transient expression of coFGF2, coVEGF165, ratFGF2 and ratVEGFA with direct transport of transcripts from distal part to proximal part of the sciatic nerve. Immunohistochemical staining revealed prolonged presence of VEGFA in sciatic nerve till 14 days post-injection. These findings suggest that local administration of plasmid construct рBud-coVEGF165-coFGF2 at a concentration of 30 ng/µL results in the formation of pro-angiogenic stimuli and, and the plasmid construct, used as a drug for gene therapy, might potentially facilitate regeneration of the sciatic nerve. The study was approved by the Animal Ethics Committee of Kazan Federal University, procedures were approved by the Local Ethics Committee (approval No. 5) on May 27, 2014.

Regulatory T cells counteract neuropathic pain through inhibition of the Th1 response at the site of peripheral nerve injury

The inflammatory/immune response at the site of peripheral nerve injury participates in the pathophysiology of neuropathic pain. Nevertheless, little is known about the local regulatory mechanisms underlying peripheral nerve injury that counteracts the development of pain. Here, we investigated the contribution of regulatory T (Treg) cells to the development of neuropathic pain by using a partial sciatic nerve ligation model in mice. We showed that Treg cells infiltrate and proliferate in the site of peripheral nerve injury. Local Treg cells suppressed the development of neuropathic pain mainly through the inhibition of the CD4 Th1 response. Treg cells also indirectly reduced neuronal damage and neuroinflammation at the level of the sensory ganglia. Finally, we identified IL-10 signaling as an intrinsic mechanism by which Treg cells counteract neuropathic pain development. These results revealed Treg cells as important inhibitory modulators of the immune response at the site of peripheral nerve injury that restrains the development of neuropathic pain. In conclusion, the boosting of Treg cell function/activity might be explored as a possible interventional approach to reduce neuropathic pain development after peripheral nerve damage.

T cells modulate IL-4 expression by eosinophil recruitment within decellularized scaffolds to repair nerve defects

Decellularized nerve, or acellular nerve allografts (ANAs), are an increasingly used alternative to nerve autografts to repair nerve gaps to facilitate regeneration. The adaptive immune system, specifically T cells, plays a role in promoting regeneration upon these ANA scaffolds. However, how T cells promote regeneration across ANAs is not clear. Here, we show that T cells accumulate within ANAs repairing nerve gaps resulting in regulation of cytokine expression within the ANA environment. This in turn ultimately leads to robust nerve regeneration and functional recovery. Nerve regeneration across ANAs and functional recovery in Rag1KO mice was limited compared to wild-type (WT) mice. Prior to appreciable nerve regeneration, ANAs from Rag1KO mice contained fewer eosinophils and reduced IL-4 expression compared to ANAs from WT mice. During this period, both T cells and eosinophils regulated IL-4 expression within ANAs. Eosinophils represented the majority of IL-4 expressing cells within ANAs, while T cells regulated IL-4 expression. Finally, an essential role for IL-4 during nerve regeneration across ANAs was confirmed as nerves repaired using ANAs had reduced regeneration in IL-4 KO mice compared to WT mice. Our data demonstrate T cells regulate the expression of IL-4 within the ANA environment via their effects on eosinophils. STATEMENT OF SIGNIFICANCE: The immune system has been emerging as a critical component for tissue regeneration, especially when regeneration is supported upon biomaterials. The role of T cells, and their roles in the regeneration of nerve repaired with biomaterials, is still unclear. We demonstrated that when nerves are repaired with decellularized nerve scaffolds, T cells contribute to regeneration by regulating cytokines. We focused on their regulation of cytokine IL-4. Unexpectedly, T cells do not produce IL-4, but instead regulate IL-4 by recruiting eosinophils, which are major cellular sources of IL-4 within these scaffolds. Thus, our work demonstrated how IL-4 is regulated in a model biomaterial, and has implications for improving the design of biomaterials and understanding immune responses to biomaterials.

Immunomodulation by Schwann cells in disease

Schwann cells are the principal glial cells of the peripheral nervous system which maintain neuronal homeostasis. Schwann cells support peripheral nerve functions and play a critical role in many pathological processes including injury-induced nerve repair, neurodegenerative diseases, infections, neuropathic pain and cancer. Schwann cells are implicated in a wide range of diseases due, in part, to their ability to interact and modulate immune cells. We discuss the accumulating examples of how Schwann cell regulation of the immune system initiates and facilitates the progression of various diseases. Furthermore, we highlight how Schwann cells may orchestrate an immunosuppressive tumor microenvironment by polarizing and modulating the activity of the dendritic cells.

Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis

Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.

The Secretomes of Painful Versus Nonpainful Human Schwannomatosis Tumor Cells Differentially Influence Sensory Neuron Gene Expression and Sensitivity

Schwannomatosis is a multiple tumor syndrome in which patients develop benign tumors along peripheral nerves throughout the body. The first symptom with which schwannomatosis patients often present, prior to discovery of tumors, is pain. This pain can be debilitating and is often inadequately alleviated by pharmacological approaches. Schwannomatosis-associated pain can be localized to the area of a tumor, or widespread. Moreover, not all tumors are painful, and the occurrence of pain is often unrelated to tumor size or location. We speculate that some individual tumors, but not others, secrete factors that act on nearby nerves to augment nociception by producing neuronal sensitization or spontaneous neuronal firing. We created cell lines from human SWN tumors with varying degrees of pain. We have found that conditioned medium (CM) collected from painful SWN tumors, but not that from nonpainful SWN tumors, sensitized DRG neurons, causing increased sensitivity to depolarization by KCl, increased response to noxious TRPV1 and TRPA1 agonists and also upregulated the expression of pain-associated genes in DRG cultures. Multiple cytokines were also detected at higher levels in CM from painful tumors. Taken together our data demonstrate a differential ability of painful versus non-painful human schwannomatosis tumor cells to secrete factors that augment sensory neuron responsiveness, and thus identify a potential determinant of pain heterogeneity in schwannomatosis.

Steroid-responsive demyelinating peripheral neuropathy associated with chronic lymphoproliferative disorders of natural killer cells

We herein report the findings of a 67-year-old woman with steroid-responsive multiple mononeuropathy associated with chronic natural killer (NK) cell lymphocytosis. The patient developed progressive, asymmetric weakness and numbness in all four extremities in the course of a three-month period. Nerve conduction studies revealed asymmetric demyelination in both the motor and sensory nerves, and a biopsy specimen of the sural nerve showed a conspicuous difference in the demyelination between the neighboring fascicles and the infiltration of NK cells in the endoneurium. We considered the multiple mononeuropathy in this patient to have been caused by NK cell infiltration in the endoneurium, and the observed asymmetry might have been due to differences in the NK cell intrusion among the fascicles. Corticosteroid administration resulted in a rapid neurological, electrophysiological and hematological improvement. The rapid clinical amelioration that was observed after corticosteroid therapy suggested that the neuropathy in this case had been mainly caused by the mechanical compression of the endoneurial NK cells or the inflammatory cytokines that had been released by them.

Complete Unique Genome Sequence, Expression Profile, and Salivary Gland Tissue Tropism of the Herpesvirus 7 Homolog in Pigtailed Macaques

Human herpesvirus 6A (HHV-6A), HHV-6B, and HHV-7 are classified as roseoloviruses and are highly prevalent in the human population. Roseolovirus reactivation in an immunocompromised host can cause severe pathologies. While the pathogenic potential of HHV-7 is unclear, it can reactivate HHV-6 from latency and thus contributes to severe pathological conditions associated with HHV-6. Because of the ubiquitous nature of roseoloviruses, their roles in such interactions and the resulting pathological consequences have been difficult to study. Furthermore, the lack of a relevant animal model for HHV-7 infection has hindered a better understanding of its contribution to roseolovirus-associated diseases. Using next-generation sequencing analysis, we characterized the unique genome of an uncultured novel pigtailed macaque roseolovirus. Detailed genomic analysis revealed the presence of gene homologs to all 84 known HHV-7 open reading frames. Phylogenetic analysis confirmed that the virus is a macaque homolog of HHV-7, which we have provisionally named Macaca nemestrina herpesvirus 7 (MneHV7). Using high-throughput RNA sequencing, we observed that the salivary gland tissue samples from nine different macaques had distinct MneHV7 gene expression patterns and that the overall number of viral transcripts correlated with viral loads in parotid gland tissue and saliva. Immunohistochemistry staining confirmed that, like HHV-7, MneHV7 exhibits a natural tropism for salivary gland ductal cells. We also observed staining for MneHV7 in peripheral nerve ganglia present in salivary gland tissues, suggesting that HHV-7 may also have a tropism for the peripheral nervous system. Our data demonstrate that MneHV7-infected macaques represent a relevant animal model that may help clarify the causality between roseolovirus reactivation and diseases.

IMPORTANCE Human herpesvirus 6A (HHV-6A), HHV-6B, and HHV-7 are classified as roseoloviruses. We have recently discovered that pigtailed macaques are naturally infected with viral homologs of HHV-6 and HHV-7, which we provisionally named MneHV6 and MneHV7, respectively. In this study, we confirm that MneHV7 is genetically and biologically similar to its human counterpart, HHV-7. We determined the complete unique MneHV7 genome sequence and provide a comprehensive annotation of all genes. We also characterized viral transcription profiles in salivary glands from naturally infected macaques. We show that broad transcriptional activity across most of the viral genome is associated with high viral loads in infected parotid glands and that late viral protein expression is detected in salivary duct cells and peripheral nerve ganglia. Our study provides new insights into the natural behavior of an extremely prevalent virus and establishes a basis for subsequent investigations of the mechanisms that cause HHV-7 reactivation and associated disease.

Activated Schwann cells in pancreatic cancer are linked to analgesia via suppression of spinal astroglia and microglia

OBJECTIVE

The impact of glia cells during GI carcinogenesis and in cancer pain is unknown. Here, we demonstrate a novel mechanism how Schwann cells (SCs) become activated in the pancreatic cancer (PCa) microenvironment and influence spinal activity and pain sensation.

DESIGN

Human SCs were exposed to hypoxia, to pancreatic cancer cells (PCCs) and/or to T-lymphocytes. Both SC and intrapancreatic nerves of patients with PCa with known pain severity were assessed for glial intermediate filament and hypoxia marker expression, proliferation and for transcriptional alterations of pain-related targets. In conditional PCa mouse models with selective in vivo blockade of interleukin (IL)-6 signalling (Ptf1a-Cre;LSL-Kras(G12D)/KC interbred with IL6(-/-) or sgp130(tg) mice), SC reactivity, abdominal mechanosensitivity and spinal glial/neuronal activity were quantified.

RESULTS

Tumour hypoxia, PCC and/or T-lymphocytes activated SC via IL-6-signalling in vitro. Blockade of the IL-6-signalling suppressed SC activation around PCa precursor lesions (pancreatic intraepithelial neoplasia (PanIN)) in KC;IL6(-/-) (32.06%±5.25% of PanINs) and KC;sgp130(tg) (55.84%±5.51%) mouse models compared with KC mice (78.27%±3.91%). Activated SCs were associated with less pain in human PCa and with decreased abdominal mechanosensitivity in KC mice (von Frey score of KC: 3.9±0.5 vs KC;IL6(-/-) mice: 5.9±0.9; and KC;sgp130(tg): 10.21±1.4) parallel to attenuation of spinal astroglial and/or microglial activity. Activated SC exhibited a transcriptomic profile with anti-inflammatory and anti-nociceptive features.

CONCLUSIONS

Activated SC in PCa recapitulate the hallmarks of 'reactive gliosis' and contribute to analgesia due to suppression of spinal glia. Our findings propose a mechanism for how cancer might remain pain-free via the SC-central glia interplay during cancer progression.

Niche heterogeneity in the bone marrow

In adult mammals, hematopoietic stem cells (HSCs) are defined by their abilities to self-renew and to differentiate to form all blood cell lineages. These rare multipotent cells occupy specific locations in the bone marrow (BM) microenvironment. The specific microenvironment regulating HSCs, commonly referred to as the niche, comprises multiple cell types whose exact contributions are under active investigation. Understanding cellular cross talk involving HSCs in the BM microenvironment is of fundamental importance for harnessing therapies against benign and malignant blood diseases. In this review, we summarize and evaluate recent advances in our understanding of niche heterogeneity and its influence on HSC function.

Molecules involved in the crosstalk between immune- and peripheral nerve Schwann cells

Schwann cells are the myelinating glial cells of the peripheral nervous system and establish myelin sheaths on large caliber axons in order to accelerate their electrical signal propagation. Apart from this well described function, these cells revealed to exhibit a high degree of differentiation plasticity as they were shown to re- and dedifferentiate upon injury and disease as well as to actively participate in regenerative- and inflammatory processes. This review focuses on the crosstalk between glial- and immune cells observed in many peripheral nerve pathologies and summarizes functional evidences of molecules, regulators and factors involved in this process. We summarize data on Schwann cell's role presenting antigens, on interactions with the complement system, on Schwann cell surface molecules/receptors and on secreted factors involved in immune cell interactions or para-/autocrine signaling events, thus strengthening the view for a broader (patho) physiological role of this cell lineage.

Novel distribution of cluster of differentiation 200 adhesion molecule in glial cells of the peripheral nervous system of rats and its modulation after nerve injury

This study examined CD200 expression in different peripheral nerves and ganglia. Intense CD200 immunoreactivity was consistently localized in unmyelinated nerve fibers as opposed to a faint immunostaining in the myelinated nerve fibers. By light microscopy, structures resembling the node of Ranvier and Schmidt-Lanterman incisures in the myelinated nerve fibers displayed CD200 immunoreactivity. Ultrastructural study revealed CD200 expression on the neurilemma of Schwann cells whose microvilli and paranodal loops at the node of Ranvier were immunoreactive. The CD200 immunoexpression was also localized in the satellite glial cells of sensory and autonomic ganglia and in the enteric glial cells. Double labeling of CD200 with specific antigens of satellite glia or Schwann cells in the primary cultures of dorsal root ganglia had shown a differential expression of CD200 in the peripheral glial cells. The existence of CD200 in glial cells in the peripheral nervous system (PNS) was corroborated by the expression of CD200 mRNA and protein in a rat Schwann cell line RSC96. Using the model of crush or transected sciatic nerve, it was found that CD200 expression was attenuated or diminished at the site of lesion. A remarkable feature, however, was an increase in incidence of CD200-labelled Schmidt-Lanterman incisures proximal to the injured site at 7 days postlesion. Because CD200 has been reported to impart immunosuppressive signal, we suggest that its localization in PNS glial cells may play a novel inhibitory role in immune homeostasis in both normal and pathological conditions.

Functional cooperation of of IL-1β and RGS4 in the brachial plexus avulsion mediated brain reorganization

BACKGROUNDS

There is considerable evidence that central nervous system is continuously modulated by activity, behavior and skill acquisition. This study is to examine the reorganization in cortical and subcortical regions in response to brachial plexus avulsion.

METHODS

Adult C57BL/6 mice were divided into four groups: control, 1, 3 and 6 month of brachial plexus avulsion. IL-1β, IL-6 and RGS4 expression in cortex, brainstem and spinal cord were detected by BiostarM-140 s microarray and real-time PCR. RGS4 subcellular distribution and modulation were further analyzed by primary neuron culture and Western Blot.

RESULTS

After 1, 3 and 6 months of brachial plexus avulsion, 49 (0 up, 49 down), 29 (17 up, 12 down), 13 (9 up, 4 down) genes in cerebral cortex, 40 (8 up, 32 down), 11 (7 up, 4 down), 137 (63 up, 74 down) in brainstem, 27 (14 up, 13 down), 33 (18 up, 15 down), 60 (29 up, 31 down) in spinal cord were identified. Among the regulated gene, IL-1β and IL-6 were sustainable enhanced in brain stem, while PKACβ and RGS4 were up-regulated throughout cerebral cortex, brainstem and spinal cord in 3 and 6 month of nerve injury. Intriguingly, subcellular distribution of RGS4 in above three regions was dependent on the functional correlation of PKA and IL-1β.

CONCLUSION

Data herein indicated that brachial plexus avulsion could efficiently initiate and perpetuate the brain reorganization. Network involved IL-1β and RGS4 signaling might implicate in the re-establish and strengthening of the local circuits at the cortical and subcortical levels.