IFN-beta suppresses experimental autoimmune neuritis in Lewis rats by inhibiting the migration of inflammatory cells into peripheral nervous tissue

P2X7 receptor antagonists modulate experimental autoimmune neuritis via regulation of NLRP3 inflammasome activation and Th17 and Th1 cell differentiation

BACKGROUND

Guillain-Barré syndrome (GBS), a post-infectious, immune-mediated, acute demyelinating disease of the peripheral nerves and nerve roots, represents the most prevalent and severe acute paralyzing neuropathy. Purinergic P2X7 receptors (P2X7R) play a crucial role in central nervous system inflammation. However, little is known about their role in the immune-inflammatory response within the peripheral nervous system.

METHODS

Initially, we assessed the expression of purinergic P2X7R in the peripheral blood of patients with GBS using flow cytometry and qRT-PCR. Next, we explored the expression of P2 X7R in CD4+ T cells, CD8+ T cells, and macrophages within the sciatic nerves and spleens of rats using immunofluorescence labeling and flow cytometry. The P2X7R antagonist brilliant blue G (BBG) was employed to examine its therapeutic impact on rats with experimental autoimmune neuritis (EAN) induced by immunization with the P0180 - 199 peptide. We analyzed CD4+ T cell differentiation in splenic mononuclear cells using flow cytometry, assessed Th17 cell differentiation in the sciatic nerve through immunofluorescence staining, and examined the expression of pro-inflammatory cytokine mRNA using RT-PCR. Additionally, we performed protein blotting to assess the expression of P2X7R and NLRP3-related inflammatory proteins within the sciatic nerve. Lastly, we utilized flow cytometry and immunofluorescence labeling to examine the expression of NLRP3 on CD4+ T cells in rats with EAN.

RESULTS

P2X7R expression was elevated not only in the peripheral blood of patients with GBS but also in rats with EAN. In rats with EAN, inhibiting P2X7R with BBG alleviated neurological symptoms, reduced demyelination, decreased inflammatory cell infiltration of the peripheral nerves, and improved nerve conduction. BBG also limited the production of pro-inflammatory molecules, down-regulated the expression of P2X7R and NLRP3, and suppressed the differentiation of Th1 and Th17 cells, thus protecting against EAN. These effects collectively contribute to modifying the inflammatory environment and enhancing outcomes in EAN rats.

CONCLUSIONS

Suppression of P2X7R relieved EAN manifestation by regulating CD4+ T cell differentiation and NLRP3 inflammasome activation. This finding underscores the potential significance of P2X7R as a target for anti-inflammatory treatments, advancing research and management of GBS.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain-Barré syndrome

BACKGROUND

Plasma exchange and intravenous immunoglobulin, but not corticosteroids, are beneficial in Guillain-Barré syndrome (GBS). The efficacy of other pharmacological agents is unknown. This review was first published in 2011 and previously updated in 2013, and 2016.

OBJECTIVES

To assess the effects of pharmacological agents other than plasma exchange, intravenous immunoglobulin and corticosteroids for GBS.

SEARCH METHODS

On 28 October 2019, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, and Embase for treatments for GBS. We also searched clinical trials registries.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) or quasi-RCTs of acute GBS (within four weeks from onset) of all types and degrees of severity, and in individuals of all ages. We discarded trials that investigated only corticosteroids, intravenous immunoglobulin or plasma exchange. We included other pharmacological treatments or combinations of treatments compared with no treatment, placebo or another treatment.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We found six trials of five different interventions eligible for inclusion in this review. The trials were conducted in hospitals in Canada, China, Germany, Japan and the UK, and included 151 participants in total. All trials randomised participants aged 16 years and older (mean or median age in the trials ranged from 36 to 57 years in the intervention groups and 34 to 60 years in the control groups) with severe GBS, defined by the inability to walk unaided. One trial also randomised patients with mild GBS who were still able to walk unaided. We identified two new trials at this update.The primary outcome measure for this review was improvement in disability grade four weeks after randomisation. Four of six trials had a high risk of bias in at least one respect. We assessed all evidence for the outcome mean improvement in disability grade as very low certainty, which means that we were unable to draw any conclusions from the data. One RCT with 19 participants compared interferon beta-1a (IFNb-1a) and placebo. It is uncertain whether IFNb-1a improves disability after four weeks (mean difference (MD) -0.1; 95% CI -1.58 to 1.38; very low-certainty evidence). A trial with 10 participants compared brain-derived neurotrophic factor (BNDF) and placebo. It is uncertain whether BDNF improves disability after four weeks (MD 0.75; 95% CI -1.14 to 2.64; very low-certainty evidence). A trial with 37 participants compared cerebrospinal fluid (CSF) filtration and plasma exchange. It is uncertain whether CSF filtration improves disability after four weeks (MD 0.02; 95% CI -0.62 to 0.66; very low-certainty evidence). One trial that compared the Chinese herbal medicine tripterygium polyglycoside with corticosteroids with 43 participants did not report the risk ratio (RR) for an improvement by one or more disability grade after four weeks, but did report improvement after eight weeks. It is uncertain whether tripterygium polyglycoside improves disability after eight weeks (RR 1.47; 95% CI 1.02 to 2.11; very low-certainty evidence). We performed a meta-analysis of two trials comparing eculizumab and placebo with 41 participants. It is uncertain whether eculizumab improves disability after four weeks (MD -0.23; 95% CI -1.79 to 1.34; very low-certainty evidence). Serious adverse events were uncommon in each of the trials and evidence was graded as either low or very low. It is uncertain whether serious adverse events were more common with IFNb-1a versus placebo (RR 0.92, 95% CI 0.23 to 3.72; 19 participants), BNDF versus placebo (RR 1.00, 95% CI 0.28 to 3.54; 10 participants) or CSF filtration versus plasma exchange (RR 0.13, 95% CI 0.01 to 2.25; 37 participants). The trial of tripterygium polyglycoside did not report serious adverse events. There may be no clear difference in the number of serious adverse events after eculizumab compared to placebo (RR 1.90, 0.34 to 10.50; 41 participants). We found no clinically important differences in any of the outcome measures selected for this review in any of the six trials. However, sample sizes were small and therefore clinically important benefit or harm cannot be excluded.

AUTHORS' CONCLUSIONS

All six RCTs were too small to exclude clinically important benefit or harm from the assessed interventions. The certainty of the evidence was low or very low for all interventions and outcomes.

Biological Drugs in Guillain-Barré Syndrome: An Update

Background:

Guillain-Barré Syndrome (GBS) is currently considered the most common global cause of acute flaccid paralysis. Currently, standard therapy for Guillain-Barré Syndrome includes intravenous immunoglobulin or plasma exchange. Despite medical advances regarding these treatments, many treated patients do not reach full recovery. Therefore several biological agents have attracted the attentions from researchers during the last decades, and various studies have investigated their role in Guillain-Barré Syndrome.

Objective:

The present study aims to address emerging biological approaches to GBS while considering their efficiency and safety in treating the disease.

Materials and Methods:

An extensive electronic literature search was conducted by two researchers from April 2016 to July 2016. Original articles, clinical trials, systematic reviews (with or without meta-analysis) and case reports were selected. Titles and abstracts of papers were screened by reviewers to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

Results:

Herein authors focused on the literature data concerning emerging biological therapeutic agents, namely anti-C5 monoclonal antibody (Eculizumab), anti-C1q monoclonal antibody, anti-T cell monoclonal antibody, anti-CD2 monoclonal antibody, anti L-selectin monoclonal antibody, anti-CD20 monoclonal antibody (Rituximab), anti-CD52 monoclonal antibody (Alemtuzumab) and cytokine targets. By far, none of these agents have been approved for the treatment of GBS by FDA.

Conclusion:

Literature findings represented in current review herald promising results for using these biological targets. Current review represents a summary of what is already in regards and what progress is required to improve the immunotherapeutic approach of treating GBS via future studies.

Class I PI3K inhibitor ZSTK474 attenuates experimental autoimmune neuritis by decreasing the frequency of Th1/Th17 cells and reducing the production of proinflammatory cytokines

The Class I phosphatidylinositol 3-kinase inhibitor, 2-(2-difluoromethy lbenzimidazol-1-yl)-4,6-dimorpholino-1,3,5-triazine (ZSTK474), has anti-inflammatory and immunoregulatory properties. However, whether it can be used to treat Guillain-Barré syndrome (GBS)-a neuroinflammatory disorder-is unknown. We induced experimental autoimmune neuritis (EAN) in Lewis rats, an established model of GBS. Orally administered ZSTK474 decreased neurological deficits in the GBS model, as demonstrated by diminished inflammatory cell infiltration, and ameliorated demyelination of sciatic nerves. Additionally, ZSTK474 decreased the number of Th1/Th17 cells and levels of the proinflammatory cytokines interleukin (IL)-1α, IL-1β, IL-17, IL-23, interferon-γ, and tumor necrosis factor-α. We propose that the phosphoinositide 3-kinase/AKT/mammalian target of rapamycin complex 1 (PI3K/AKT/mTORC1) pathway likely contributed to the neuroprotective effect of ZSTK474. ZSTK474 effectively decreases the frequency of Th1/Th17 cells, thereby reducing the production of proinflammatory cytokines and successfully alleviating the symptoms of EAN. Thus, the neuroprotective effect of ZSTK474 indicates its potential utility as anti-inflammatory therapy for GBS.

Cytokine Signaling in Multiple Sclerosis and Its Therapeutic Applications

Multiple sclerosis (MS) is one of the most common neurological disorders in young adults. The etiology of MS is not known but it is widely accepted that it is autoimmune in nature. Disease onset is believed to be initiated by the activation of CD4+ T cells that target autoantigens of the central nervous system (CNS) and their infiltration into the CNS, followed by the expansion of local and infiltrated peripheral effector myeloid cells that create an inflammatory milieu within the CNS, which ultimately lead to tissue damage and demyelination. Clinical studies have shown that progression of MS correlates with the abnormal expression of certain cytokines. The use of experimental autoimmune encephalomyelitis (EAE) model further delineates the role of these cytokines in neuroinflammation and the therapeutic potential of manipulating their biological activity in vivo. In this review, we will first present an overview on cytokines that may contribute to the pathogenesis of MS or EAE, and provide successful examples and roadblock of translating data obtained from EAE to MS. We will then focus in depth on recent findings that demonstrate the pathological role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in MS and EAE, and briefly discuss the potential of targeting effector myeloid cells as a treatment strategy for MS.

A role for interferon-beta in Guillain-Barré Syndrome?

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating neuropathy that is associated with long-lasting morbidity and a substantial risk of mortality. The 2 reference treatments, plasma exchange and intravenous immunoglobulins (IVIg), do not change the functional prognosis for the most severely ill patients. The pathogenesis of GBS involves humoral and cellular immune dysfunctions that have only recently been characterised. Antibodies to nerve antigens may participate in complement activation, antibody-dependent macrophage cytotoxicity and reversible conduction failure. The cellular immune reaction is associated with increases in pro-inflammatory cytokines [such as tumour necrosis factor-alpha (TNFalpha)] and matrix metalloproteinases (MMPs; e.g. MMP-9), and a decrease in anti-inflammatory cytokines [such as transforming growth factor-beta1 (TGFbeta1)]. All the changes favour adhesion to and transmigration across the endothelium of immune cells, a key phenomenon associated with GBS. Recovery from GBS is characterised by the normalisation of these changes. Experimental allergic neuritis (EAN), the experimental model of GBS, has strikingly similar immunological characteristics. The usual treatment options for patients with GBS (plasma exchange and IVIg) mainly target the humoral component of the immune response. Interferon-beta (IFNbeta) is a cellular immunomodulator that inhibits antigen presentation and TNFalpha production and binding, and modulates macrophage properties. IFNbeta increases anti-inflammatory T cell functions and the production of anti-inflammatory cytokines, such as TGFbeta1. IFNbeta has important effects on leukodiapedesis, caused by modulating the expression of cell adhesion molecules and the MMP-9 proteinases. It has been used with success in EAN, in some patients with acute exacerbation of chronic inflammatory demyelinating polyneuropathy, and in 1 patient with GBS. The pathophysiology of patients with GBS, an understanding of IFNbeta properties and results of experimental studies support the investigation of IFNbeta in trials of patients with GBS.

Experimental autoimmune encephalomyelitis in Lewis rats: IFN-beta acts as a tolerogenic adjuvant for induction of neuroantigen-dependent tolerance

Cytokine-Ag fusion proteins represent a novel approach for induction of Ag-specific tolerance and may constitute an efficient therapy for autoimmune disease. This study addressed whether a fusion protein containing rat IFN-beta and the encephalitogenic 73-87 determinant of myelin basic protein (i.e., the neuroantigen, or NAg) could prevent or treat experimental autoimmune encephalomyelitis (EAE) in Lewis rats. The optimal structure of the fusion protein was comprised of the rat IFN-beta cytokine as the N-terminal domain with an enterokinase (EK) linker to the NAg domain. Both cytokine and NAg domains had full biological activity. Subcutaneous administration of 1 nmol of IFNbeta-NAg fusion protein in saline on days -21, -14, and -7 before encephalitogenic challenge on day 0 resulted in a substantial attenuation of EAE. In contrast, administration of IFN-beta or NAg alone did not affect susceptibility to EAE. The covalent attachment of IFN-beta and NAg was not necessary, because separate injections of IFN-beta and NAg at adjacent sites were as effective as injection of IFNbeta-NAg for prevention of disease. When treatment was initiated after disease onset, the rank order of inhibitory activity was as follows: the IFNbeta-NAg fusion protein > or = a mixture of IFN-beta plus NAg > IFN-beta > NAg. The novel finding that IFN-beta acts as a tolerogenic adjuvant as well as a tolerogenic fusion partner may have significance for development of tolerogenic vaccines.

Beneficial effects of r-h-CLU on disease severity in different animal models of peripheral neuropathies

Clusterin is a protein involved in multiple biological events, including neuronal cytoprotection, membrane recycling and regulation of complement-mediated membrane attack after injury. We investigated the effect of recombinant human clusterin in preclinical models of peripheral neuropathies. Daily treatment with clusterin accelerated the recovery of nerve motor evoked potential parameters after sciatic nerve injury. Prophylactic or therapeutic treatment of experimental autoimmune neuritis rats with clusterin also accelerated the rate of recovery from the disease, associated with remyelination of demyelinated nerve fibers. These data demonstrate that clusterin is capable of ameliorating clinical, neurophysiological and pathological signs in models of peripheral neuropathies.

Soluble TNFR1 inhibits the development of experimental autoimmune neuritis by modulating blood–nerve-barrier permeability and inflammation

The role of TNFalpha/LTalpha during EAN induced by active immunization with peripheral nerve myelin was examined by administering a recombinant soluble chimeric form of human TNF receptor 1 (TNFR1-IgG). TNFalpha and LTalpha do not directly contribute to neurological deficit during EAN since treatment with TNFR1-IgG after onset failed to alter the course of disease. Prophylaxis with a single dose of TNFR1-IgG delayed the onset of EAN and was accompanied initially by inhibition of blood-nerve-barrier permeability and inflammation. Subsequently, the number of infiltrating macrophages and blood-nerve-barrier permeability increased but the disease symptoms remained mild for five days (on average a limp tail) after which severe EAN developed. The antibody titer to peripheral nerve myelin was unaltered by prophylaxis with TNFR1-IgG. The markedly altered tempo of disease onset after TNFR1-IgG prophylaxis indicates that TNFalpha and/or LTalpha have a key role in the development of blood-nerve-barrier permeability and the coupling of macrophage activation and recruitment to peripheral nerve pathology during EAN.

Inhibition of Ras attenuates the course of experimental autoimmune neuritis

EAN induced in Lewis rats by immunization with peripheral bovine myelin was treated by the Ras inhibitor farnesylthiosalicylate (FTS). Treatment from day 0 with FTS (5 mg/kg intraperitoneally twice daily) attenuated peak clinical scores (mean+/-S.E., 2.5+/-0.5 compared to 4.1+/-0.5 in saline treated controls, p=0.018, t-test) but not recovery. Treatment from day 10 with FTS attenuated peak disability (2.5+/-0.6, p=0.032 compared to saline treated controls) and improved recovery (0.84+/-0.42, untreated controls 2.4+/-0.6, p=0.028 by repeated measures ANOVA). Effects were confirmed by rotarod and nerve conduction studies. An inactive analogue, geranylthiosalicylate, had no clinical effect. Inhibition of Ras is of potential use in the treatment of inflammatory neuropathies.

Interferon and the central nervous system

Interferons (IFNs) were discovered as natural antiviral substances produced during viral infection and were initially characterized for their ability to "interfere" with viral replication, slow cell proliferation, and profound alteration of immunity. The IFNs are synthesized and secreted by monocytes, macrophages, T-lymphocytes, neurons, and glia cells. The different IFNs are classified into three classes: alpha, beta, and gamma. alpha-IFN produced in the brain exerts direct effects on the brain and endocrine system by activating the neurosecretory hypothalamic neurons and regulates the hypothalamic-pituitary-adrenocortical axis. IFNs modulate neurophysiological activities of many brain region involving in pain, temperature, and food intake regulation. alpha-IFN administration activates the sympathetic nerves innervating components of the immune system. IFNs may serve as regulatory mediators between the central nervous system, the immune system, and endocrine system. IFN is used as immunologic therapy to treat various hematologic malignancies and infectious ailments and autoimmune diseases.

Differential regulation of innate and adaptive immune responses in viral encephalitis

Viral encephalitis is a global health concern. The ability of a virus to modulate the immune response can have a pivotal effect on the course of disease and the fate of the infected host. In this study, we sought to understand the immunological basis for the fatal encephalitis following infection with the murine coronavirus, mouse hepatitis virus (MHV)-JHM, in contrast with the more attenuated MHV-A59. Distinct glial cell cytokine and chemokine response patterns were observed within 3 days after infection, became progressively more polarized during the course of infection and with the infiltration of leukocytes. In the brain, MHV-JHM infection induced strong accumulation of IFNbeta mRNA relative to IFNgamma mRNA. This trend was reversed in MHV-A59 infection and was accompanied by increased CD8 T cell infiltration into brain compared to MHV-JHM infection. Increased apoptosis appeared to contribute to the diminished presence of CD8 T cells in MHV-JHM-infected brain with the consequence of a lower potential for IFNgamma production and antiviral activity. MHV-JHM infection also induced sustained mRNA accumulation of the innate immune response products interleukin (IL)-6 and IL-1. Furthermore, high levels of macrophage-inflammatory protein (MIP)-1alpha, MIP-1beta, and MIP-2 mRNA were observed at the onset of MHV-JHM infection and correlated with a marked elevation in the number of macrophages in the brain on day 7 compared to MHV-A59 infection. These observations indicate that differences in the severity of viral encephalitis may reflect the differential ability of viruses to stimulate innate immune responses within the CNS and subsequently the character of infiltrating leukocyte populations.

Expression, purification, and characterization of rat interferon-β, and preparation of an N-terminally PEGylated form with improved pharmacokinetic parameters

To identify potential new clinical uses and routes of administration for human interferon-beta-1a (IFN-beta-1a), we have developed an expression and purification procedure for the preparation of highly purified rat interferon-beta (IFN-beta) suitable for testing in rat models of human disease. An expression vector containing the rat IFN-beta signal sequence and structural gene was constructed and transfected into Chinese hamster ovary (CHO) cells. The protein was purified from CHO cell conditioned medium and purified to > 99.5% purity using standard chromatographic techniques. Analytical characterization indicated that the protein was a heavily glycosylated monomeric protein, with two of the four predicted N-glycosylation sites occupied. Analysis of the attached oligosaccharides showed them to be a complex mixture of bi-antennary, tri-antennary, and tetra-antennary structures with a predominance of sialylated tri-antennary and tetra-antennary structures. Peptide mapping, N-terminal sequencing, and mass spectrometry confirmed the identity and integrity of the purified protein. The purified protein had a specific activity of 2.1x10(8)U/mg when assayed on rat RATEC cells, which is similar in magnitude to the potencies observed for murine IFN-beta and human IFN-beta-1a assayed on murine and human cells, respectively. We also prepared an N-terminally PEGylated form of rat IFN-beta in which a 20 kDa methoxy polyethylene glycol (PEG)-propionaldehyde was attached to the N-terminal alpha-amino group of Ile-1. The PEGylated protein, which retained essentially full in vitro antiviral activity, had improved pharmacokinetic parameters in rats as compared to the unmodified protein. Both the unmodified and PEGylated forms of rat IFN-beta will be useful for testing in rat models of human disease.

Propagermanium suppresses macrophage-mediated formation of coronary arteriosclerotic lesions in pigs in vivo

Although the importance of monocytes/macrophages in the pathogenesis of arteriosclerosis is widely accepted, effective and safe treatment to inhibit those inflammatory cells remains to be developed. It was recently found that propagermanium, which is clinically used for the treatment of chronic hepatitis type B in Japan, markedly suppresses monocyte chemotaxis in response to macrophage chemoattractant protein-1 (MCP-1) through inhibition of its receptor, C-C chemokine receptor 2, in vitro. This prompted examination of whether propagermanium suppresses the macrophage-mediated formation of coronary arteriosclerotic lesions in our porcine model in vivo. It was first confirmed that propagermanium inhibited the migration of porcine monocytes in response to MCP-1 at therapeutic concentrations in vitro. Pigs were randomly divided into two groups; one group was orally treated with propagermanium (1 mg/kg, three times/day) and another group served as a control (n = 6 each). Porcine coronary segment was treated from the adventitia with MCP-1 and oxidized low-density lipoprotein for 2 weeks. In the control group, this treatment resulted in the development of stenotic coronary lesions with hyperconstrictive responses to serotonin where arteriosclerotic lesions (neointimal formation and constrictive remodeling) were developed. Immunohistochemical analysis demonstrated the macrophage accumulation in the adventitia and the media. By contrast, in the propagermanium group, angiographic coronary stenosis, hyperconstrictive responses, histologic changes, and macrophage accumulation were all significantly suppressed. These results indicate that propagermanium suppresses macrophage-mediated formation of coronary arteriosclerotic lesions in vivo, suggesting its potential usefulness for the treatment of arteriosclerotic vascular diseases.