Expression of Toll-like receptors 2, 4 and 9 in patients with Guillain-Barré syndrome

Immune-Mediated Neuropathies: Pathophysiology and Management

Dysfunction of the immune system can result in damage of the peripheral nervous system. The immunological mechanisms, which include macrophage infiltration, inflammation and proliferation of Schwann cells, result in variable degrees of demyelination and axonal degeneration. Aetiology is diverse and, in some cases, may be precipitated by infection. Various animal models have contributed and helped to elucidate the pathophysiological mechanisms in acute and chronic inflammatory polyradiculoneuropathies (Guillain-Barre Syndrome and chronic inflammatory demyelinating polyradiculoneuropathy, respectively). The presence of specific anti-glycoconjugate antibodies indicates an underlying process of molecular mimicry and sometimes assists in the classification of these disorders, which often merely supports the clinical diagnosis. Now, the electrophysiological presence of conduction blocks is another important factor in characterizing another subgroup of treatable motor neuropathies (multifocal motor neuropathy with conduction block), which is distinct from Lewis-Sumner syndrome (multifocal acquired demyelinating sensory and motor neuropathy) in its response to treatment modalities as well as electrophysiological features. Furthermore, paraneoplastic neuropathies are also immune-mediated and are the result of an immune reaction to tumour cells that express onconeural antigens and mimic molecules expressed on the surface of neurons. The detection of specific paraneoplastic antibodies often assists the clinician in the investigation of an underlying, sometimes specific, malignancy. This review aims to discuss the immunological and pathophysiological mechanisms that are thought to be crucial in the aetiology of dysimmune neuropathies as well as their individual electrophysiological characteristics, their laboratory features and existing treatment options. Here, we aim to present a balance of discussion from these diverse angles that may be helpful in categorizing disease and establishing prognosis.

DAP12 deletion causes age-related motor function impairment but promotes functional recovery after sciatic nerve crush injury

DNAX activating protein of 12 kDa (DAP12)-deficiency mice showed impaired differentiation of oligodendrocytes and reduced myelin in the central nervous system. Whether DAP12 is expressed by Schwann cells and its roles in the peripheral nervous system (PNS) remains unknown. In this study, expression of DAP12 was detected in Schwann cells in vivo and in vitro. The DAP12-knockout (KO) mice showed age-related motor deficits and thinner myelin in the sciatic nerve than WT mice but significantly faster clinical recovery after sciatic nerve crush injury. In sciatic nerves of DAP12 KO and WT mice, proteomic profiles analysis identified 158 differentially expressed proteins (DEPs) at 8-week-old, 29 DEPs at 54-week-old and 33 DEPs at two weeks after crush injury. Typically, of the DEPs at 54-week-old, up-regulated Lgmn and down-regulated RecK and Yap1 were associated with myelin loss in the sciatic nerve of DAP12 KO mice. Upregulation of nicotinamide nucleotide transhydrogenase and haptoglobin were associated with the accumulation of macrophages in the crushed sciatic nerve of DAP12 KO mice. After crush injury, there were significantly more M1 macrophages at one-week and more M2 macrophages at two-week in sciatic nerve of DAP12 KO mice than WT mice, indicating that DAP12 deletion promotes the phenotype conversion of macrophages from M1 to M2. Collectively, our findings suggest that DAP12 may exert dual roles in the PNS including promoting the physiological myelin formation and maintenance of Schwann cells but delaying nerve repair after injury by modulating the recruitment of macrophages and phenotype conversion.

NPT1220-312, a TLR2/TLR9 Small Molecule Antagonist, Inhibits Pro-Inflammatory Signaling, Cytokine Release, and NLRP3 Inflammasome Activation

Toll-like receptors (TLRs) play a critical role in innate immune system responses to damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). A growing body of evidence suggests that excessive TLR-mediated innate immune system activation can lead to neuronal damage and precipitate or perpetuate neurodegenerative diseases. Among TLR subtypes, both TLR2 and TLR9 have been implicated in neurodegenerative disorders with increased expression of these receptors in the central nervous system being associated with pro-inflammatory signaling and increased burdens of pathologic aggregated proteins. In the current study, we characterized the actions of a combined TLR2/TLR9 antagonist, NPT1220-312, on pro-inflammatory signaling and cytokine release in monocyte/macrophage-derived heterologous cells, human microglia, and murine and human whole blood. NPT1220-312 potently blocked TLR2- and TLR9-mediated release of inflammatory cytokines in monocyte/macrophage cells and in human microglia. NPT1220-312 also blocked TLR2-mediated activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome including IL-1β, IL-18, and apoptosis-associated speck-like protein containing a CARD (ASC) release to the culture medium of human differentiated macrophages. The ability of NPT1220-312 to inhibit TLR2 mediated pro-inflammatory release of chemokines and cytokines in situ was demonstrated using murine and human whole blood. Together, these findings suggest that blockade of TLR2 and TLR9 may reduce inappropriate production of pro-inflammatory cytokines and chemokines from peripheral and central immune cells and thus potentially provide therapeutic benefit in neuroinflammatory/neurodegenerative disorders.

Variations within Toll-like receptor (TLR) and TLR signalling pathway-related genes and their synergistic effects on the risk of Guillain-Barré Syndrome

Guillain-Barré Syndrome (GBS) is the commonest postinfectious polyradiculopathy. Though genetic background of the host seems to play an important role in the susceptibility to GBS, genes conferring major risk are not yet known. Dysregulation of Toll-like receptor (TLR) molecules exacerbates immune-inflammatory responses and the genetic variations within TLR pathway-related genes contribute to differential risk to infection. To delineate the impact of genetic variations within TLR2, TLR3, and TLR4 genes and TLR signaling pathway-related genes such as MyD88, TRIF, TRAF3, TRAF6, IRF3, NFκβ1, and IκBα on risk of developing GBS. Fourteen polymorphisms located within TLR2 (rs3804099; rs111200466), TLR3 (rs3775290; rs3775291), TLR4 (rs1927911, rs11536891), MyD88 (rs7744, rs4988453), TRIF (rs8120 TRAF3 (rs12147254), TRAF6 (rs4755453), IRF3 (rs2304204), NFκβ1 (rs28362491) and IκBα (rs696) genes were genotyped in 150 GBS patients and 150 healthy subjects either by PCR-RFLP or TaqMan Allelic Discrimination Assay. Genotypes of two polymorphic variants, Del/Del of rs111200466 Insertion and Deletion (INDEL) polymorphism of TLR2 gene and TT of rs3775290 single nucleotide polymorphism (SNP) of TLR3 gene had significantly higher frequencies among GBS patients, while the frequencies of TT genotype of rs3804099 of TLR2 gene and TT genotype of rs11536891 SNP of TLR4 gene were significantly higher in controls. Gene-gene interaction study by Multifactor Dimensionality Reduction (MDR) analysis also suggested a significant combined effect of TLR2, and NFκβ1 genes on the risk of GBS. The SNPs in the IκBα and IRF3 genes correlated with severity of GBS. The genes encoding TLRs and TLR signalling pathway-related molecules could serve as crucial genetic markers of susceptibility and severity of GBS. This article is protected by copyright. All rights reserved.

Role of Toll-Like Receptors in Neuroimmune Diseases: Therapeutic Targets and Problems

Toll-like receptors (TLRs) are a class of proteins playing a key role in innate and adaptive immune responses. TLRs are involved in the development and progression of neuroimmune diseases via initiating inflammatory responses. Thus, targeting TLRs signaling pathway may be considered as a potential therapy for neuroimmune diseases. However, the role of TLRs is elusive and complex in neuroimmune diseases. In addition to the inadequate immune response of TLRs inhibitors in the experiments, the recent studies also demonstrated that partial activation of TLRs is conducive to the production of anti-inflammatory factors and nervous system repair. Exploring the mechanism of TLRs in neuroimmune diseases and combining with developing the emerging drug may conquer neuroimmune diseases in the future. Herein, we provide an overview of the role of TLRs in several neuroimmune diseases, including multiple sclerosis, neuromyelitis optica spectrum disorder, Guillain-Barré syndrome and myasthenia gravis. Emerging difficulties and potential solutions in clinical application of TLRs inhibitors will also be discussed.

Triangle of cytokine storm, central nervous system involvement, and viral infection in COVID-19: the role of sFasL and neuropilin-1

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is identified as the cause of coronavirus disease 2019 (COVID-19), and is often linked to extreme inflammatory responses by over activation of neutrophil extracellular traps (NETs), cytokine storm, and sepsis. These are robust causes for multi-organ damage. In particular, potential routes of SARS-CoV2 entry, such as angiotensin-converting enzyme 2 (ACE2), have been linked to central nervous system (CNS) involvement. CNS has been recognized as one of the most susceptible compartments to cytokine storm, which can be affected by neuropilin-1 (NRP-1). ACE2 is widely-recognized as a SARS-CoV2 entry pathway; However, NRP-1 has been recently introduced as a novel path of viral entry. Apoptosis of cells invaded by this virus involves Fas receptor-Fas ligand (FasL) signaling; moreover, Fas receptor may function as a controller of inflammation. Furthermore, NRP-1 may influence FasL and modulate cytokine profile. The neuroimmunological insult by SARS-CoV2 infection may be inhibited by therapeutic approaches targeting soluble Fas ligand (sFasL), cytokine storm elements, or related viral entry pathways. In the current review, we explain pivotal players behind the activation of cytokine storm that are associated with vast CNS injury. We also hypothesize that sFasL may affect neuroinflammatory processes and trigger the cytokine storm in COVID-19.

Inhibition of TLR4 signaling protects mice from sensory and motor dysfunction in an animal model of autoimmune peripheral neuropathy

BACKGROUND

While the etiology remains elusive, macrophages and T cells in peripheral nerves are considered as effector cells mediating autoimmune peripheral neuropathy (APN), such as Guillain-Barre syndrome. By recognizing both pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) signals, TLRs play a central role in the initiation of both innate and adaptive immune responses. In this study, we aimed to understand the involvement of TLR4 in the pathogenesis of APN and explore the potential of TLR4 as a drug target for therapeutic use.

METHODS

APN was induced by a partial ligation on one of the sciatic nerves in B7.2 (L31) transgenic mice which possess a predisposed inflammatory background. APN pathology and neurological function were evaluated on the other non-injured sciatic nerve.

RESULTS

TLR4 and its endogenous ligand HMGB1 were highly expressed in L31 mice, in circulating immune cells and in peripheral nerves. Enhanced TLR4 signaling was blocked with TAK 242, a selective TLR4 inhibitor, before and after disease onset. Intraperitoneal administration of TAK 242 not only inhibited monocyte, macrophage and CD8⁺ T cell activation, but also reduced the release of pro-inflammatory cytokines. TAK 242 protected mice from severe myelin and axonal loss, resulting in a remarkable improvement in mouse motor and sensory functions. TAK 242 was effective in alleviating the disease in both preventive and reversal paradigms.

CONCLUSION

The study identified the critical contribution of TLR4-mediated macrophage activation in disease course and provided strong evidence to support TLR4 as a useful drug target for treating inflammatory autoimmune neuropathy.

Fulminant Guillain-Barré Syndrome and Spontaneous Intraventricular Hemorrhage: A Case Report and Literature Review

Guillain–Barré syndrome (GBS) is an acute, immune-mediated inflammatory peripheral polyneuropathy that is characterized by flaccid paralysis. A few cases have reported that GBS can be caused by head trauma or neurosurgery, but it has never been associated with intraventricular hemorrhage. Here, we report an uncommon case of fulminant GBS that occurred after spontaneous intraventricular hemorrhage. A 73-year-old woman was admitted to the hospital after sudden unconsciousness and vomiting. A head computed tomography (CT) scan following the incident showed a newly developed intraventricular hemorrhage, which led to an immediate ventriculostomy. After 5 days, the endotracheal tube was removed. Two days later, the external ventricular drainage tube was also removed. At this time, the patient was alert and the neurological examination was normal. However, the patient suddenly presented with acute respiratory failure and bilateral limb weakness 3 days later. An analysis of the patient’s cerebrospinal fluid (CSF) revealed that albuminocytologic dissociation was present. The patient was treated with intravenous immunoglobulin (0.4 g/kg/day) for 5 days. Despite timely medical intervention in the hospital, the patient passed away 2 months later. After a cerebral hemorrhagic injury, limb and respiratory muscle weakness can occur on occasion in the ICU. In this context, the potential involvement of GBS should not be ignored. Importantly, the pathogenic mechanism of GBS has been discussed for over a century, and it still remains a mystery. We speculate that the TLR4/NF-κB signaling pathway may be involved in the pathogenesis of GBS following intraventricular hemorrhage. The prognosis of most patients with GBS is usually good, but cerebral hemorrhage and mechanical ventilation may serve as risk factors that exacerbate the condition. This case is reported to remind clinicians to consider the possibility of GBS when patients present limb and respiratory muscle weakness after intraventricular hemorrhage, and to provide a starting point to discuss potential mechanisms of GBS after intraventricular hemorrhage.

Immunomodulatory and anti-oxidative effect of the direct TRPV1 receptor agonist capsaicin on Schwann cells

Background

Only few studies describe the impact of nutritive factors on chronic inflammatory demyelinating polyneuropathy (CIDP), an inflammatory disease of the peripheral nervous system. The active component of chili pepper, capsaicin, is the direct agonist of the transient receptor potential channel vanilloid subfamily member 1. Its anti-inflammatory effect in the animal model experimental autoimmune neuritis (EAN) has been previously demonstrated.

Methods

In the present study, we describe the anti-inflammatory and anti-oxidative influence of capsaicin on Schwann cells (SCs) in an in vitro setting. Hereby, we analyze the effect of capsaicin on Schwann cells’ gene expression pattern, major histocompatibility complex class II (MHC-II) presentation, and H₂O₂-induced oxidative stress. Furthermore, the effect of capsaicin on myelination was examined in a SC-dorsal root ganglia (DRG) coculture by myelin basic protein staining. Finally, in order to investigate the isolated effect of capsaicin on SCs in EAN pathology, we transplant naïve and capsaicin pre-treated SCs intrathecally in EAN immunized rats and analyzed clinical presentation, electrophysiological parameters, and cytokine expression in the sciatic nerve.

Results

In SC monoculture, incubation with capsaicin significantly reduces interferon gamma-induced MHC-II production as well as toll-like receptor 4 and intercellular adhesion molecule 1 mRNA expression. Calcitonin gene-related peptide mRNA production is significantly upregulated after capsaicin treatment. Capsaicin reduces H₂O₂-induced oxidative stress in SC in a preventive, but not therapeutic setting. In a SC-DRG coculture, capsaicin does not affect myelination rate. After intrathecal transplantation of naïve and capsaicin pre-treated SCs in EAN-immunized rats, naïve, but not capsaicin pre-treated intrathecal SCs, ameliorated EAN pathology in rats.

Conclusions

In conclusion, we were able to demonstrate a direct immunomodulatory and anti-oxidative effect of capsaicin in a SC culture by reduced antigen presentation and expression of an anti-inflammatory profile. Furthermore, capsaicin increases the resistance of SCs against oxidative stress. A primary effect of capsaicin on myelination was not proven. These results are in concordance with previous data showing an anti-inflammatory effect of capsaicin, which might be highly relevant for CIDP patients.

Inflammatory Role of TLR-MyD88 Signaling in Multiple Sclerosis

Multiple sclerosis (MS) is a neuro-autoimmune and neurodegenerative disorder leading to chronic inflammation, demyelination, axonal, and neuronal loss in the central nervous system (CNS). Despite intense research efforts, the pathogenesis of MS still remains unclear. Toll-like receptors (TLRs) are a family of type I transmembrane receptors that play a crucial role in the innate immune response. Myeloid differentiation factor 88 (MyD88) is the adaptor of major TLRs. It has been widely considered that the TLR-MyD88 signaling pathway plays an important role in the occurrence and development of autoimmune disease. Data have revealed that the TLR-MyD88 signaling may be involved in the pathogenesis of MS and experimental autoimmune encephalomyelitis (EAE), an animal model for MS, by regulating the antigen presentation of dendritic cells, the integrity of blood-brain barrier (BBB), and the activation of T cells and B cells. Here, we summarize the role of TLRs and MyD88 in MS and discuss the possible therapies that are based on these molecules.

Peripheral Blood and Cerebrospinal Fluid Cytokine Levels in Guillain Barré Syndrome: A Systematic Review and Meta-Analysis

Background: Guillain Barré Syndrome (GBS) is an autoimmune disorder caused by the immune-mediated damage of the peripheral nervous system. Increasing evidence suggests that inflammatory cytokines are important mediators for the onset and progression of GBS. A number of clinical studies have demonstrated elevated levels of T helper-1 (Th1-), Th2-, and Th17-related cytokines in patients with GBS; however, the results were inconsistent across studies.

Methods: We performed a systematic review and a meta-analysis of studies comparing the levels of inflammatory cytokines in the cerebrospinal fluid and peripheral blood between patients with GBS and healthy individuals, using Comprehensive Meta-Analysis Version 2 software. A database search identified 30 studies comprising 1,302 patients with GBS and 1,073 healthy controls.

Results: The random-effects meta-analysis demonstrated that peripheral blood tumor necrosis factor-α (Hedges g, 1.544; 95% confidence interval (CI), 0.923–2.165; p < 0.001), interleukin-1β (IL-1β; Hedges g, 0.678; 95% CI, 0.183–1.172; p = 0.007), IL-6 (Hedges g, 0.630; 95% CI, 0.100–1.160; p = 0.02), IL-4 (Hedges g, 0.822; 95% CI, 0.220–1.423; p = 0.007), IL-17 (Hedges g, 1.452; 95% CI, 0.331–2.573; p = 0.011), interferon-γ (Hedges g, 1.104; 95% CI, 0.490–1.719; p < 0.001), and C-reactive protein (Hedges g, 0.909; 95% CI, 0.453–1.365; p < 0.001) levels were significantly increased in patients with GBS when compared with healthy controls. Contrastingly, the blood IL-10 and transforming growth factor-β levels were not significantly associated with GBS. Furthermore, the meta-analysis found that cerebrospinal fluid IL-17 levels were significantly associated with GBS (Hedges g, 1.882; 95% CI, 0.104–3.661; p = 0.038).

Conclusion: Altogether, our results clarified the circulating inflammatory cytokine profile in patients with GBS, and revealed that Th1-, Th2-, and Th17-related cytokines were highly elevated in the GBS patients, suggesting the potential use of these cytokines as biomarkers for GBS.

Roles of macrophage migration inhibitory factor in Guillain-Barré syndrome and experimental autoimmune neuritis: beneficial or harmful?

INTRODUCTION

Macrophage migration inhibitory factor (MIF) plays an important role in the pathogenesis of Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN), which may offer an opportunity for the development of the novel therapeutic strategies for GBS. Areas covered: 'macrophage migration inhibitory factor' and 'Guillain-Barré syndrome' were used as keywords to search for related publications on Pub-Med, National Center for Biotechnology Information (NCBI), USA. MIF is involved in the etiology of various inflammatory and autoimmune disorders. However, the roles of MIF in GBS and EAN have not been summarized in the publications we identified. Therefore, in this review, we described and analyzed the major roles of MIF in GBS/EAN. Primarily, this molecule aggravates the inflammatory responses in this disorder. However, multiple studies indicated a protective role of MIF in GBS. The potential of MIF as a therapeutic target in GBS has been recently demonstrated in experimental and clinical studies, although clinical trials have been unavailable to date. Expert opinion: MIF plays a critical role in the initiation and progression of GBS and EAN, and it may represent a potential therapeutic target for GBS.

Transcriptome Analysis of Peripheral Blood in Chronic Inflammatory Demyelinating Polyradiculoneuropathy Patients Identifies TNFR1 and TLR Pathways in the IVIg Response

We have studied the response to intravenous immunoglobulins (IVIg) by a transcriptomic approach in 11 chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients (CIDP duration = 6 [0.83-6.5] years). RNA was extracted from cells in whole blood collected before and 3 weeks after IVIg treatment, and hybridized on Illumina chips. After RNA quality controls, gene expression was analyzed using statistical tests fitted for microarrays (R software, limma package), and a pathway analysis was performed using DAVID software. We identified 52 genes with expression that varied significantly after IVIg (fold change [FC] > 1.2, P < 0.001, false discovery rate [FDR] <0.05). Among these 52 genes, 7 were related to immunity, 3 were related to the tumor necrosis factor (TNF)-α receptor 1 (TNFR1) pathway (inhibitor of caspase-activated DNase (ICAD): FC = 1.8, P = 1.7E-7, FDR = 0.004; p21 protein-activated kinase 2 [PAK2]: FC = 1.66, P = 2.6E-5, FDR = 0.03; TNF-α-induced protein 8-like protein 1 [TNFAIP8L1]: P = 1.00E-05, FDR = 0.026), and 2 were related to Toll-like receptors (TLRs), especially TLRs 7 and 9, and were implicated in autoimmunity. These genes were UNC93B1 (FC = 1.6, P = 2E-5, FDR = 0.03), which transports TLRs 7 and 9 to the endolysosomes, and RNF216 (FC = 1.5, P = 1E-05, FDR = 0.03), which promotes TLR 9 degradation. Pathway analysis showed that the TNFR1 pathway was significantly lessened by IVIg (enrichment score = 24, Fischer exact test = 0.003). TNF-α gene expression was higher in responder patients than in nonresponders; however, it decreased after IVIg in responders (P = 0.04), but remained stable in nonresponders. Our data suggest the actions of IVIg on the TNFR1 pathway and an original mechanism involving innate immunity through TLRs in CIDP pathophysiology and the response to IVIg. We conclude that responder patients have stronger inflammatory activity that is lessened by IVIg.

Increased plasmacytoid dendritic cells in Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a post-infectious autoimmune disease. Dendritic cells (DCs) can recognize the pathogen and modulate the host immune response. Exploring the role of DCs in GBS will help our understanding of the disease development. In this study, we aimed to analyze plasmacytoid and conventional DCs in peripheral blood of patients with GBS at different stages of the disease: acute phase as well as early and late recovery phases. There was a significant increase of plasmacytoid DCs in the acute phase (p=0.03 vs healthy donors). There was a positive correlation between percentage of plasmacytoid DCs and the clinical severity of patients with GBS (r=0.61, p<0.001). Quantitative polymerase chain reaction and flow cytometry confirmed the aberrant plasmacytoid DCs in GBS. Thus, plasmacytoid DCs may participate in the development of GBS.

Role of cytokines and Toll-like receptors in the immunopathogenesis of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune disease of the peripheral nervous system, mostly triggered by an aberrant immune response to an infectious pathogen. Although several infections have been implicated in the pathogenesis of GBS, not all such infected individuals develop this disease. Moreover, infection with a single agent might also lead to different subtypes of GBS emphasizing the role of host factors in the development of GBS. The host factors regulate a broad range of inflammatory processes that are involved in the pathogenesis of autoimmune diseases including GBS. Evidences suggest that systemically and locally released cytokines and their involvement in immune-mediated demyelination and axonal damage of peripheral nerves are important in the pathogenesis of GBS. Toll-like receptors (TLRs) link innate and adaptive immunity through transcription of several proinflammatory cytokines. TLR genes may increase susceptibility to microbial infections; an attenuated immune response towards antigen and downregulation of cytokines occurs due to mutation in the gene. Herein, we discuss the crucial role of host factors such as cytokines and TLRs that activate the immune response and are involved in the pathogenesis of the disease.

Update on Guillain-Barré syndrome

Understanding of Guillain-Barré syndrome (GBS) has progressed substantially since the seminal 1916 report by Guillain et al. Although Guillain, Barré, and Strohl summarised the syndrome based on observations of two French infantrymen, 2012 saw the beginning of an ambitious collaborative study designed to collect detailed data from at least 1,000 patients worldwide (IGOS, www.gbsstudies.org/about-igos). Progress has been made in many areas even since GBS was last reviewed in this journal in 2009. GBS subsequently received prominent attention in light of concerns regarding H1N1 influenza vaccinations, and several large-scale surveillance studies resulted. Despite these developments, and promising pre-clinical studies, disease-modifying therapies for GBS have not substantially altered since intravenous immunoglobulin was introduced over 20 years ago. In other areas, management has improved. Antibiotic prophylaxis in ventilated patients reduces respiratory tract infection, thromboprophylaxis has reduced the risk of venous thromboembolism, and there is increasing awareness of the benefit of high-intensity rehabilitation. This article highlights some of the interesting and thought-provoking developments of the last 3 years, and is based on a plenary lecture given at the 2012 Peripheral Nerve Society (PNS) meeting.

Silencing of miR155 promotes the production of inflammatory mediators in Guillain-Barré syndrome in vitro

MicroRNA-155 (miR155) has been demonstrated as a central regulator of immune responses induced by inflammatory mediators. Previous studies suggest that miR155 may play adverse effects in various diseases. We hereby explored the roles of miR155 in the pathogenesis of Guillain-Barré syndrome (GBS). Peripheral blood mononuclear cells (PBMCs) were separated from GBS patients and healthy controls. Expression of miR155 in PBMCs was detected by quantitative PCR. An inhibitor of miR155 was transfected into the cultured PBMCs and the GBS-related cytokines were detected. Significantly, our study demonstrated that miR155 was downregulated in PBMCs from GBS patients and silencing of miR155 profoundly promoted the production of Th1-type cytokines in vitro. Our data effectively demonstrate a protective role of miR155 in GBS, which suggests that miR155 may be a promising target for the therapy of the disease.