Experimental Autoimmune Neuritis Research Articles

Antibiotics-Induced Intestinal Immunomodulation Attenuates Experimental Autoimmune Neuritis (EAN)

BackgroundThe composition of gut microbiota plays a pivotal role in priming the immune system and thus impacts autoimmune diseases. Data on the effects of gut bacteria eradication via systemic antibiotics on immune neuropathies are currently lacking. This study therefore assessed the effects of antibiotics-induced gut microbiota alterations on the severity of experimental autoimmune neuritis (EAN), a rat model of Guillain-Barré Syndrome (GBS). Myelin P0 peptide 180–199 (P0 180–199)-induced EAN severity was compared between adult Lewis rats (12 weeks old) that received drinking water with or without antibiotics (colistin, metronidazole, vancomycin) and healthy rats, beginning antibiotics treatment immediately after immunization (day 0), and continuing treatment for 14 consecutive days. Neuropathy severity was assessed via a modified clinical score, and then related to gut microbiota alterations observed after fecal 16S rRNA gene sequencing at baseline and after EAN induction. Effectors of gut mucosal and endoneurial immunity were assessed via immunostaining. EAN rats showed increased gut mucosal permeability alongside increased mucosal CD8+ T cells compared to healthy controls. Antibiotics treatment alleviated clinical EAN severity and reduced endoneurial T cell infiltration, decreased gut mucosal CD8+ T cells and increased gut bacteria that may be associated with anti-inflammatory mechanisms, like Lactobacillus or Parasutterella. Our findings point out a relation between gut mucosal immunity and the pathogenesis of EAN, and indicate that antibiotics-induced intestinal immunomodulation might be a therapeutic approach to alleviate autoimmunity in immune neuropathies. Further studies are warranted to evaluate the clinical transferability of these findings to patients with GBS.Graphical

Guillain-Barré syndrome: History, pathogenesis, treatment, and future directions.

Since its description by Guillain, Barré, and Strohl in 1916, Guillain-Barré syndrome (GBS) has attracted a large literature. The author reviews the history of research into its pathogenesis and treatment to highlight promising avenues for future research. This is a nonsystematic personal review. Since the early 1900s, the clinical picture of GBS has been illustrated in multiple series culminating in the ongoing International Guillain-Barré Syndrome study of 2000 patients. In the 1950s and 1960s, the inflammatory nature of the commonest form, acute inflammatory demyelinating polyradiculoneuropathy (AIDP), was described. In the 1990s, two axonal forms, acute motor-sensory axonal neuropathy and acute motor axonal neuropathy, were recognized. In the 1990s and early 2000s, these forms were shown to be due to antibodies against Campylobacter jejuni glycans cross-reacting with glycolipids on axonal membranes. The pathogenesis of AIDP remains unknown, but T-cell responses to the compact myelin proteins, P2 and P0, which cause experimental autoimmune neuritis, suggest that T cells are important. Randomized controlled trials in the 1970s and 1980s showed no benefit from corticosteroids. Trials in the 1980s showed benefit from plasma exchange and in the 1990s from intravenous immunoglobulin. Future research should seek biomarkers to identify subgroups with different treatment responses, define the true natural history of the disease with population-based epidemiological studies, study the pathology in autopsies early in the disease, seek causative antibodies and confirm autoimmune T-cell responses in AIDP, and expand treatment trials to include anti-T-cell agents.

Clinical Relevance of Plasma Prolylcarboxypeptidase Level in Patients with Idiopathic Acute Optic Neuritis.

Objectives: This study evaluated the plasma concentration of prolylcarboxypeptidase (PRCP) and its clinical relevance in patients with idiopathic acute optic neuritis (ON). Methods: We investigated the expression of PRCP in the optic nerves of experimental autoimmune optic neuritis (EAON)-induced mice. Peripheral blood samples were collected from ON patients (n = 20) and healthy controls (n = 20). ELISA was used to measure the plasma PRCP levels. We performed measurements of visual acuity and the mean thicknesses of the macular ganglion cell layer plus inner plexiform layer (GCL+IPL) at diagnosis and 6 months after diagnosis. Results: The PRCP mRNA expression in EAON-induced mice was markedly higher than that in naïve mice. The mean plasma PRCP level was significantly higher in patients with ON than in controls. Plasma PRCP levels were negatively correlated with logMAR visual acuity at 6 months after diagnosis and differences in macular GCL+IPL thickness during an ON attack. A plasma PRCP level of 49.98 (pg/mL) predicted the recurrence of ON with a 75% sensitivity and 87.5% specificity. Conclusions: Patients with idiopathic acute ON had higher plasma PRCP levels, and this was positively correlated with final visual outcome and well-preserved macular GCL+IPL thickness during an ON attack. The increase in plasma PRCP level may reflect its compensatory secretion to counteract neuroinflammation in ON patients.

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

BackgroundGuillain–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.MethodsInitially, 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.ResultsP2X7R 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.ConclusionsSuppression 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.

Small fibre integrity and axonal pathology in the rat model of experimental autoimmune neuritis.

Experimental autoimmune neuritis is a common animal model for acute human immune-mediated polyneuropathies. Although already established in 1955, a number of pathophysiological mechanisms remain unknown. In this study, we extensively characterize experimental autoimmune neuritis progression in Lewis rats, including new insights into the integrity of small nerve fibres, neuropathic pain and macrophage activation. Acute experimental autoimmune neuritis was induced with P253-78 peptide and consequently investigated using the gait analysis system CatWalk XT, electrophysiological and histopathological analyses, quantitative polymerase chain reaction (PCR), dorsal root ganglia outgrowth studies, as well as the von Frey hair and Hargreaves tests. For the longitudinal setup, rats were sacrificed at Day (d) 10 (onset), d15 (peak), d26 (recovery) and d29 (late recovery). We confirmed the classical T-cell and macrophage-driven inflammation and the primarily demyelinating nature of the experimental autoimmune neuritis. The dual role of macrophages in experimental autoimmune neuritis is implicated by the high number of remaining macrophages throughout disease progression. Furthermore, different subpopulations of macrophages based on Cx3-motif chemokine receptor 1 (Cx3cr1), platelet factor 4 (Pf4) and macrophage galactose-type lectin-1 (Mgl1) expressions were identified. In addition, modulation of the sensory system in experimental autoimmune neuritis was detected. An outgrowth of small fibres in the plantar skin at the onset and peak of the experimental autoimmune neuritis was evident parallel to the development of acute hyperalgesia mediated through transient receptor potential vanilloid 1 modulation. Our data depict experimental autoimmune neuritis as a primary demyelinating disease with implicated axonal damage, a small unmyelinated fibre impairment throughout the disease progression course, and underline the pivotal role of macrophages in the effector and during the recovery stage.

Small fiber integrity and axonal pathology in the rat model of experimental autoimmune neuritis

Small fiber integrity and axonal pathology in the rat model of experimental autoimmune neuritis

2,4-Dinitrophenol does not exert neuro-regenerative potential in experimental autoimmune neuritis

ObjectiveWe evaluated the potential neuro-regenerative effects of the mitochondrial uncoupler 2,4-Dinitrophenol in experimental autoimmune neuritis, an animal model for an acute autoimmune neuropathy. MethodsExperimental autoimmune neuritis was induced in Lewis rats. Different concentrations of 2,4-Dinitrophenol (1 mg/kg, 0.1 mg/kg and 0.01 mg/kg) were applied during the recovery phase of the neuritis (at days 18, 22 and 26) and compared to the vehicle. Any effects were assessed through functional, electrophysiological, and morphological analysis via electron microscopy of all groups at day 30. Additional immune-histochemical analysis of inflammation markers and remyelination of the sciatic nerves were performed for the dosage of 1 mg/kg and control. ResultsNo enhancement of functional or electrophysiological recovery was observed in all 2,4-Dinitrophenol-treated groups. Cellular inflammation markers of T cells (CD3+) were comparable to control, and an increase of macrophages (IbA1+) invasion in the sciatic nerves was observed. Treatment with 2,4-Dinitrophenol reduced axonal swelling in myelinated and unmyelinated fibers with an increased production of brain-derived neurotrophic factor. ConclusionOur findings do not support the hypothesis that repurposing of the mitochondrial uncoupler 2,4-Dinitrophenol exerts functionally relevant neuro-regenerative effects in autoimmune neuritis.

Kinesin-5 inhibition improves neural regeneration in experimental autoimmune neuritis

BackgroundAutoimmune neuropathies can result in long-term disability and incomplete recovery, despite adequate first-line therapy. Kinesin-5 inhibition was shown to accelerate neurite outgrowth in different preclinical studies. Here, we evaluated the potential neuro-regenerative effects of the small molecule kinesin-5 inhibitor monastrol in a rodent model of acute autoimmune neuropathies, experimental autoimmune neuritis.MethodsExperimental autoimmune neuritis was induced in Lewis rats with the neurogenic P2-peptide. At the beginning of the recovery phase at day 18, the animals were treated with 1 mg/kg monastrol or sham and observed until day 30 post-immunisation. Electrophysiological and histological analysis for markers of inflammation and remyelination of the sciatic nerve were performed. Neuromuscular junctions of the tibialis anterior muscles were analysed for reinnervation. We further treated human induced pluripotent stem cells-derived secondary motor neurons with monastrol in different concentrations and performed a neurite outgrowth assay.ResultsTreatment with monastrol enhanced functional and histological recovery in experimental autoimmune neuritis. Motor nerve conduction velocity at day 30 in the treated animals was comparable to pre-neuritis values. Monastrol-treated animals showed partially reinnervated or intact neuromuscular junctions. A significant and dose-dependent accelerated neurite outgrowth was observed after kinesin-5 inhibition as a possible mode of action.ConclusionPharmacological kinesin-5 inhibition improves the functional outcome in experimental autoimmune neuritis through accelerated motor neurite outgrowth and histological recovery. This approach could be of interest to improve the outcome of autoimmune neuropathy patients.

Lactobacillus paracasei L9 affects disease progression in experimental autoimmune neuritis by regulating intestinal flora structure and arginine metabolism

BackgroundAutoimmune neuropathies are common peripheral nervous system (PNS) disorders. Environmental influences and dietary components are known to affect the course of autoimmune diseases. Intestinal microorganisms can be dynamically regulated through diet, and this study combines intestinal microorganisms with diseases to open up new therapeutic ideas.MethodsIn Lewis rats, a model of EAN was established with P0 peptide, Lactobacillus were used as treatment, serum T-cell ratio, inflammatory factors, sciatic neuropathological changes, and pathological inflammatory effects on intestinal mucosa were detected, and fecal metabolomics and 16 s microbiome analysis were performed to further explore the mechanism.ResultsIn the EAN rat model, Lactobacillus paracasei L9 (LP) could dynamically regulate the CD4+/CD8+T balance in serum, reduce serum IL-1, IL-6 and TNF-α expression levels, improve sciatic nerve demyelination and inflammatory infiltration, and reduce nervous system score. In the rat model of EAN, intestinal mucosa was damaged. Occludin and ZO-1 were downregulated. IL-1, TNF-α and Reg3γ were upregulated. LP gavage induced intestinal mucosa recovery; occludin and ZO-1 upregulation; IL-1, TNF-α and Reg3γ downregulation. Finally, metabolomics and 16 s microbiome analysis were performed, and differential metabolites were enriched with an important metabolic pathway, arginine and proline metabolism.ConclusionLP improved EAN in rats by influencing intestinal community and the lysine and proline metabolism.

Expression of glycolytic genes in immune cells and changes of related immune cells in experimental autoimmune neuritis

Objective: To investigate the expression of glycolytic genes in immune cells and the changes of related immune cells in experimental autoimmune neuritis (EAN), and deepen the understanding of pathogenesis of EAN. Methods: Twenty-four male C57BL/6 mice (6-8 weeks old, 18-20 g) were divided into four groups according to the random number table method: control group (P0180-199 was replaced by PBS during modeling and mice were sacrificed on the 16th day), EAN mice were sacrificed on the 8th day after the end of modeling (EAN 8 d), EAN mice were sacrificed on the 16th day after the end of modeling (EAN 16 d), and EAN mice received drug intervention and were sacrificed on the 16th day after the end of modeling (2-DG was intraperitoneally injected since the day of the first immunization, 550 mg/kg; EAN 16 d+2-DG), with 6 rats in each group. The clinical symptoms and clinical scores were observed and recorded daily. At the end of the experiment, the mice were sacrificed under chloral hydrate anesthesia, and the serum, spleen, sciatic nerve and other tissues of each group were collected. The degree of inflammatory cell infiltration and demyelination of sciatic nerve were observed by hematoxylin and eosin (HE) staining and luxol fast blue (LFB) staining. Flow cytometry was used to detect the proportion of M1 macrophages, Th17 cells and Tregs cells. The mRNA expression levels of glycolysis-related genes (mTORC1, HIF1α, GLUT1 and LDHA) were detected by RT-PCR. Western blotting was used to detect the level of pan-lysine lactate in macrophages and sciatic nerve tissue. Results: The expression of glycolysis-related genes (mTORC1, HIF1α, GLUT1 and LDHA) in spleen M1 macrophages and sciatic nerve was significantly up-regulated in EAN 16 d group, compared with control, EAN 8 d and EAN 16 d+2-DG groups (all P<0.05). The relative pan-lysine lactate (pankla) expression level of spleen M1 macrophages (1.25±0.02) and sciatic nerve tissue (1.23±0.26) significantly increased in EAN 16 d group, compared with control, EAN 8 d and EAN 16 d+2-DG groups (M1 macrophages: 0.12±0.10, 1.07±0.12 and 0.42±0.07; sciatic nerve: 0.10±0.12, 0.87±0.20 and 0.36±0.05) (all P<0.05). The expression of glycolytic genes in splenic CD4+T cells showed an increasing trend, but there were no statistically significant differences among the groups, and the expression of glycolytic genes did not decrease significantly after 2-DG treatment (all P>0.05). The proportion of spleen M1 macrophages in the control group, EAN 8 d group, EAN 16 d group and EAN 16 d+2-DG group was 4.28±0.13, 7.54±0.25, 13.16±0.33 and 4.13±0.38 respectively, which was significantly higher in the EAN 16 d group (all P<0.05). The proportion of spleen Th17 cells in the four groups was 3.78±0.03, 8.24±0.55, 12.30±1.34 and 4.83±0.01, respectively, which was significantly higher in the EAN 16 d group (all P<0.05). The proportion of spleen Tregs cells in the four groups was 10.01±1.05, 7.54±0.70, 3.82±0.47 and 8.22±1.21, respectively, which was significantly lower in the EAN 16 d group (all P<0.05). Conclusions: The expression of glycolytic genes in splenic macrophages significantly increases during EAN, but not in CD4+T cells. The proportion of M1 macrophages and Th17 cells in spleen gradually increases, while the proportion of Tregs cells gradually decreases.

Preclinical Assessment of EPO-Derived Peptide JM4 in Experimental Autoimmune Neuritis (P10-5.008)

<h3>Objective:</h3> Determine clinical efficacy of JM4, a synthetic erythropoietin-derived 19-mer peptide in experimental autoimmune neuritis (EAN). <h3>Background:</h3> Guillain-Barré syndrome, an acute inflammatory demyelinating polyneuropathy (AIDP), is an autoimmune disease causing injuries to myelinated nerves. Mild AIDP cases result in temporary motor and sensory deficits, but severe AIDP cases can also cause dysautonomia and respiratory failure leading to disability or death. Treatments include intravenous immune globulin or plasma exchange, but only 30–40% of patients experience clinical improvement. More effective interventions are needed to improve AIDP clinical outcomes. JM4 is a 19-mer peptide derived from human erythropoietin, which does not have an unwanted side effect of erythropoiesis. We demonstrated JM4 therapy had prolonged therapeutic benefits in an experimental autoimmune encephalomyelitis (EAE) model. Since inflammatory mechanisms underlying EAE are shared with EAN, an animal model for AIDP, we reasoned JM4 would also have clinical benefit in EAN. <h3>Design/Methods:</h3> EAN was induced in C57BL/6 mouse and in Lewis rat using murine peripheral nerve myelin P0 antigen and bovine myelin P2 peptide, respectively. EAN clinical scoring paradigm was used to assess neurological deficits. At deficit onset, EAN mice were administered JM4 intravenously (IV) for 10 days and EAN rats were administered JM4 IV for 3 days followed by intraperitoneal injection for 7 days. Sciatic nerves from EAN rodents were stained with Luxol fast blue to assess demyelination and with cresyl violet to assess mononuclear cell infiltration. <h3>Results:</h3> JM4 treatment reduced peak EAN clinical scores compared to sham treatment. Based on staining analysis, EAN induction caused mononuclear cell infiltration and demyelination in the sciatic nerve. <h3>Conclusions:</h3> Preliminary clinical scoring data from rodent models suggest JM4 may have therapeutic benefits in EAN models. Further studies are needed to correlate improvements in clinical scoring with histological analysis of demyelination, mononuclear cell infiltration and neuroinflammatory markers in EAN models. <b>Disclosure:</b> Dr. Arismendi has nothing to disclose. The institution of Dr. Choi has received research support from Department of Veterans Affairs. Dr. Husar has nothing to disclose. Peter C. Dowling, MD has nothing to disclose. Dr. Lu has nothing to disclose.

Fingolimod ameliorates chronic experimental autoimmune neuritis by modulating inflammatory cytokines and Akt/mTOR/NF-κB signaling.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated disease that targets the myelin sheaths of the peripheral nerves. Fingolimod is a sphingosine 1 phosphate (S1P) receptor antagonist with a high affinity for S1P receptors through the Akt-mTOR pathway, and prior research has suggested that it might be helpful in autoimmune illnesses. Chronic experimental autoimmune neuritis (c-EAN) was induced by immunizing Lewis rats with the S-palm P0(180-199) peptide, and then the treatment group was intraperitoneally injected with fingolimod (1mg/kg) daily. Hematoxylin and eosin staining was used to assess the severity of nerve injury. Immunohistochemistry staining showed that fingolimod's anti-inflammatory effects on c-EAN rats might be realized through the NF-κB signaling pathway. Tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), interleukin-1beta (IL-1β), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and intercellular adhesion molecule-1 (ICAM-1) were measured to evaluate the inflammation levels, and pAkt, p-S6, and p-p65 were used to measure the abundance of downstream activation markers to determine whether the Akt/mTOR/NF-κB signaling pathway was activated in the c-EAN model. Fingolimod treatment reduced the inflammatory reaction and the expression of NF-κB in sciatic nerves. It also decreased the mRNA levels of the proinflammatory cytokines TNF-α, IFN-γ, IL-1β, IL-6, iNOS, and ICAM-1 and pAkt, p-S6, and p-p65, representing the Akt/mTOR/NF-κB signaling pathway. Our data showed that fingolimod could improve the disease course, alleviate the decrease in inflammation, and reduce proinflammatory cytokines through the Akt/mTOR/NF-κB axis in c-EAN rats, which could be beneficial for the development of CIDP-related research.

P-8 Small fiber involvement, neuropathic pain and macrophage-dependentaxonal pathology in the rat model of experimental autoimmune neuritis

P-8 Small fiber involvement, neuropathic pain and macrophage-dependentaxonal pathology in the rat model of experimental autoimmune neuritis

Siponimod ameliorates experimental autoimmune neuritis

BackgroundGuillain–Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) are human autoimmune peripheral neuropathy. Besides humoral immunity, cellular immunity is also believed to contribute to these pathologies, especially CIDP. Sphingosine-1-phosphate receptor 1 (S1PR1) regulates the maturation, migration, and trafficking of lymphocytes. As of date, the therapeutic effect of sphingosine-1-phosphate receptor (S1PR) agonists on patients with GBS or CIDP remains unclear.MethodsTo evaluate the effect of siponimod, an agonist of S1PR1 and S1PR5, on experimental autoimmune neuritis (EAN), an animal model of autoimmune peripheral neuropathy, was used. Lewis rats were immunized with 125 μg of synthetic peptide from bovine P2 protein. Rats in the siponimod group were orally administered 1.0 mg/kg siponimod and those in the EAN group were administrated the vehicle on days 5–27 post-immunization (p.i.) daily. The symptom severity was recorded daily. The changes in the expression of cytokines and transcription factors in the lymph nodes and cauda equina (CE) which correlate with the pathogenesis of EAN and recovery of injured nerve were measured using reverse transcription quantitative PCR. Histological study of CE was also performed.ResultsFlaccid paralysis developed on day 11 p.i. in both groups. Siponimod relieved the symptom severity and decreased the expression of interferon-gamma and IL-10 mRNAs in lymph nodes and CE compared with that in the EAN group. The expression of Jun proto-oncogene (c-Jun) mRNA increased from the peak to the recovery phase and that of Sonic hedgehog signaling molecule (Shh) and Glial cell line-derived neurotrophic factor (Gdnf) increased prior to increase in c-Jun with no difference observed between the two groups. Histologically, siponimod also reduced demyelinating lesions and inflammatory cell invasion in CE.ConclusionsSiponimod has a potential to ameliorate EAN. Shh and Gdnf, as well as C-Jun played a significant role during the recovery of injured nerves.

B.infantis enhances immunotherapy for Guillain-Barre syndrome through regulating PD-1

BackgroundGuillain-Barré syndrome (GBS) is a rare, autoimmune disease. B.infantis is reported to be effective in alleviating GBS by regulating abnormal function of T helper (Th) cells.ObjectivesIn this study, T cells were isolated from healthy and GBS patients. The therapeutic effect of Bifidobacterium infantis (B.infantis) and whether it is achieved by PD-1 was examined at cellular and animal models.MethodsWe used CCK-8, flow cytometry and real-time PCR to determine the differentiation of T cell subsets at cellular level. Then, an experimental autoimmune neuritis (EAN) animal model using six-week SD rats (n = 30, male) weighing 180–200 g was established to support the role of B. infantis in GBS through PD-1.ResultsB. infantis inhibited the proliferation and promoted apoptosis of T cells from GBS. At the same time, the expression levels of PD-1 increased, which was correlated with decreased T-bet (Th1) and ROR-γt (Th17) and increased Foxp3 (Treg) expression. Moreover, B. infantis alleviated the symptoms of GBS. Th1 and Th17 cells decreased while Treg cells increased after B. infantis treatment, which could be partly abrogated by PD-1 inhibitor.ConclusionsWe concluded from this study that B.infantis alleviated GBS partly through PD-1.

Celastrol attenuates Guillain-Barré syndrome by inhibiting TLR4/NF-κB/STAT3 pathway-mediated Th1/Th17 cell differentiation.

Guillain-Barré syndrome (GBS) is an acute immune-mediated paralytic neuropathy with variable disease course and outcome. In this study, we aimed to investigate the therapeutic effects of celastrol on GBS and uncover its underlying mechanisms. Experimental autoimmune neuritis (EAN) is a typical animal model for GBS, and thus an EAN rat model was established with the injection of celastrol or/and LPS. We assessed the body weights and EAN clinical scores of rats. HE staining, flow cytometry, RT-qPCR, and Western blotting were respectively employed to measure pathological damage, proportions of cells (Th1, Th17, and Treg), Th1/Th17 cell differentiation-related mRNAs (IFN-γ, TBX21, IL-18, RORγT, IL-17, and IL-23) and TLR4/NF-κB/STAT3 pathway-related proteins (TLR4, NF-κB, p-NF-κB, STAT3, and p-STAT3). We found that celastrol attenuated clinical symptoms and pathological damage of GBS in EAN rats. Moreover, celastrol down-regulated Th1 and Th17 cell proportions, and the levels of IFN-γ, TBX21, IL-18, RORγT, IL-17, and IL-23 in EAN rats. Meanwhile, the levels of TLR4, p-NF-κB, and p-STAT3 were decreased by celastrol. Taken together, celastrol could restrain Th1/Th17 cell differentiation through inhibition of the TLR4/NF-κB/STAT3 pathway in EAN rats. Our findings suggest that celastrol may exert therapeutic effects on GBS by suppressing TLR4/NF-κB/STAT3 pathway-mediated Th1/Th17 cell differentiation.

Sex differences in Guillain Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and experimental autoimmune neuritis.

Guillain Barré syndrome (GBS) and its variants, and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP and its variants, are regarded as immune mediated neuropathies. Unlike in many autoimmune disorders, GBS and CIDP are more common in males than females. Sex is not a clear predictor of outcome. Experimental autoimmune neuritis (EAN) is an animal model of these diseases, but there are no studies of the effects of sex in EAN. The pathogenesis of GBS and CIDP involves immune response to non-protein antigens, antigen presentation through non-conventional T cells and, in CIDP with nodopathy, IgG4 antibody responses to antigens. There are some reported sex differences in some of these elements of the immune system and we speculate that these sex differences could contribute to the male predominance of these diseases, and suggest that sex differences in peripheral nerves is a topic worthy of further study.

Immune Modifying Effect of Drug Free Biodegradable Nanoparticles on Disease Course of Experimental Autoimmune Neuritis.

Guillain-Barre syndrome (GBS) is an autoimmune disease of demyelination and inflammation of peripheral nerves. Current treatments are limited to plasma exchange and intravenous immunoglobulins. Cargo-free nanoparticles (NPs) have been evaluated here for their therapeutic benefit on the disease course of experimental autoimmune neuritis (EAN), mimicking the human GBS. NPs prepared from poly-lactic co-glycolic acid (PLGA) with variable size and surface charge (i.e., 500 nm vs. 130 nm, polyvinyl alcohol (PVA) vs. sodium cholate), were intravenously administered in before- or early-onset treatment schedules in a rat EAN model. NP treatment mitigated distinctly the clinical severity of EAN as compared to the P2-peptide control group (P2) in all treatments and reduced the trafficking of inflammatory monocytes at inflammatory loci and diverted them towards the spleen. Therapeutic treatment with NPs reduced the expression of proinflammatory markers (CD68 (P2: 34.8 ± 6.6 vs. NP: 11.9 ± 2.3), IL-1β (P2: 18.3 ± 0.8 vs. NP: 5.8 ± 2.2), TNF-α (P2: 23.5 ± 3.7 vs. NP: 8.3 ± 1.7) and elevated the expression levels of anti-inflammatory markers CD163 (P2: 19.7 ± 3.0 vs. NP: 41.1 ± 6.5; all for NP-PVA of 130 nm; relative to healthy control). These results highlight the therapeutic potential of such cargo-free NPs in treating EAN, which would be easily translatable into clinical use due to their well-known low-toxicity profile.

Notch signaling dependent monocyte conversion alleviates immune-mediated neuropathies by regulating RBP-J/NR4A1 axis

Monocytes in peripheral blood and sciatic nerves play vital roles in immune-mediated neuropathies such as Guillain-Barré syndrome (GBS). Different subpopulations of monocytes, including classical and non-classical, exhibit distinct functions as well as phenotypic conversion potentials. However, the mechanisms underlying their development during immune-mediated neuropathy remain unclear. Notch signaling participates in monocyte differentiation and function. In this study, we used a myeloid-specific Notch signaling activation transgenic mouse (NICcA) and investigated the role of Notch signaling in monocytes during experimental autoimmune neuritis (EAN) in a mouse model of GBS. Clinical score assessment and histopathological examination revealed that sciatic nerve injury was attenuated in NICcA EAN mice compared to that in control mice. Flow cytometry and immunofluorescence staining suggested that increasing Ly6Clo monocytes in the peripheral blood and nerve tissue might contribute to the alleviation of neuritis in NICcA mice. Meanwhile, an in vitro study suggested that bone marrow-derived monocytes from NICcA mice are more inclined toward Ly6Clo cells than Ly6Chi cells. Differential expression of monocyte development-associated genes was detected in NICcA and wild-type mice using RNA sequencing. The expression of Nr4a1 is upregulated remarkably when Notch signaling is activated. Treatment with Nr4a1 antagonist on NICcA mice-derived monocytes compromise their Ly6Clo tendency. Consistently, a relationship between monocyte conversion and disease severity was observed in blood samples from patients with GBS. In conclusion, our current study showed that monocyte conversion modulated by Notch signaling plays an essential role in the EAN mouse model.

Upregulation of N-Type Voltage-Gated Calcium Channels Induces Neuropathic Pain in Experimental Autoimmune Neuritis.

Objective Guillain–Barré syndrome (GBS) is a common autoimmune disease of the peripheral nervous system, and there is still no effective treatment for GBS. This investigation intends to figure out the effect and mechanism of N-type voltage-gated calcium (Cav2.2) channels on neuropathic pain in GBS. Methods An experimental autoimmune neuritis (EAN) model was established in Lewis rats induced by myelin P253-78 peptide and complete Freund's adjuvant. Luxol fast blue (LFB) staining was used for observing the degree of cell infiltration and demyelination in the sciatic nerve of rats, ELISA for detecting IL-6 and TNF-α expression in the serum, qRT-PCR, and Western blot for measuring the expression of iNOS, MCP-1, and Cav2.2 in the sciatic nerve, respectively. Results EAN led to significant decreases in the mechanical withdrawal threshold, thermal withdrawal threshold, and mechanical hyperalgesia threshold and an increase in the withdrawal threshold to cold stimulation. The serum IL-6 and TNF-α expression was significantly increased, and the mRNA and protein expression of iNOS, MCP-1, and Cav2.2 in the sciatic nerve were significantly increased in the EAN rats. However, silencing Cav2.2 expression could significantly reverse the above EAN-caused results. Conclusion Silencing Cav2.2 expression can significantly reduce the clinical score, pathological injury, and mechanical allodynia, reducing the release of inflammatory factors, thus improving neuropathic pain in EAN rats.