Autoimmune Encephalomyelitis In Rats Research Articles

The Effect of Exercise Training and Royal Jelly on Hippocampal Cannabinoid-1-Receptors and Pain Threshold in Experimental Autoimmune Encephalomyelitis in Rats as Animal Model of Multiple Sclerosis.

Cannabinoid-1-receptors (CB1R) are therapeutic targets for both the treatment of autoimmune diseases, such as multiple sclerosis (MS), and some related symptoms such as pain. The aim of this study was to evaluate the effect of aerobic training and two dosages of royal jelly (RJ) on hippocampal CB1R and pain threshold (PT) in an experimental autoimmune encephalomyelitis (EAE) model. To this end, 56 female Sprague-Dawley rats with EAE were randomly assigned to one of the following eight conditions: (1) EAE; (2) sham; (3) 50 mg/kg RJ (RJ50); (4) 100 mg/kg RJ (RJ100); (5) exercise training (ET); (6) ET + RJ50; (7) ET + RJ100; and (8) not EAE or healthy control (HC). Endurance training was performed for five weeks, four sessions per week at a speed of 11–15 m/min for 30 min, and RJ was injected peritoneally at doses of 50 and 100 mg/kg/day). One-way analysis of variance and Tukey’s post hoc tests were performed to identify group-related differences in pain threshold (PT) and CB1R gene expression. Endurance training had no significant effect on PT and hippocampal CB1R in rats with EAE. CB1R gene expression levels in the RJ100 group were higher than in the EAE group. Further, PT levels in the ETRJ50 and ETRJ100 groups were higher than in the EAE group. The combination of ET and RJ50 had a higher impact on PT and CB1R, when compared to the ET and RJ50 alone. Next, there was a dose-response between RJ-induced CB1R gene expression and RJ dosages: higher dosages of RJ increased the CB1R gene expression. The overall results suggest that the combination of ET and increasing RJ dosages improved pain threshold probably related to CB1R in an EAE model, while this was not observed for ET or RJ alone.

Lactose and Casein Cause Changes on Biomarkers of Oxidative Damage and Dysbiosis in an Experimental Model of Multiple Sclerosis.

Experimental Autoimmune Encephalomyelitis (EAE) in rats closely reproduces Multiple Sclerosis (MS), a disease characterized by neuroinflammation and oxidative stress that also appears to extend to other organs and their compartments. The origin of MS is a matter for discussion, but it would seem that altering certain bacterial populations present in the gut may lead to a proinflammatory condition due to the bacterial Lipopolysaccharides (LPS) in the so-called brain-gut axis. The casein and lactose in milk confer anti-inflammatory properties and immunomodulatory effects. The objectives of this study were to evaluate the effects of administration of casein and lactose on the oxidative damage and the clinical status caused by EAE and to verify whether both casein and lactose had any effect on the LPS and its transport protein -LBP-. Twenty male Dark Agouti rats were divided into control rats (control), EAE rats, and EAE rats, to which casein and lactose, EAE+casein, and EAE+lactose, respectively, were administered. Fifty-one days after casein and lactose administration, the rats were sacrificed, and different organs were studied (brain, spinal cord, blood, heart, liver, kidney, small, and large intestine). In the latter, products derived from oxidative stress were studied (lipid peroxides and carbonylated proteins) as well as the glutathione redox system, various inflammation factors (total nitrite, Nuclear Factor-kappa B p65, the Rat Tumour Necrosis Factor-α), and the LPS and LBP values. Casein and lactose administration improved the clinical aspect of the disease at the same time as reducing inflammation and oxidative stress, exerting its action on the glutathione redox system, or increasing GPx levels.

The expression of diacylglycerol kinase isoforms α and ζ correlates with the progression of experimental autoimmune encephalomyelitis in rats

Multiple sclerosis (MS) is characterized by neuroinflammation and neurodegeneration, whose precise processes are not fully understood. Diacylglycerol kinase (DGK) isozymes of α, β, γ and ζ expressed abundantly in the brain and/or the immune system, may be regulatory targets for MS. In this study, we analyzed the four DGK isozymes along the induction, peak and recovery phases in an experimental autoimmune encephalomyelitis (EAE) rat model of MS. The expression of these DGK isozymes and the diacylglycerol (DAG) pathway in the EAE rat brainstems were analyzed by qRT-PCR, immunohistochemistry, immunofluorescence double staining, western blotting and ELISA. Our results showed that the mRNA content of the four DGK isozymes decreased significantly, and their immunoreactivity in myelin sheathes (DGKα, β) and neurons (DGKγ, ζ) became weaker at the beginning of the induction phase. With the progressive increase in clinical signs, DGKα, DGKγ and DGKζ mRNA increased and DGKβ mRNA decreased, and microglia were involved in the formation of perivascular cuffing. In the peak phase, both DGKα and DGKζ were expressed in neurons and inflammatory cells, and DGKζ was also positive in microglia. During the recovery phase, the mRNA content and immunoreactivity of these DGK isozymes generally reached normal levels. Moreover, our results revealed that changes in DAG accumulation and PKCδ phosphorylation were almost the same as those of DGKα and DGKζ mRNA. In summary, the four DGK isozymes are involved in the EAE process. The predominant and broad presence of DGKα and DGKζ suggests that they may regulate the pathological process by attenuating DAG/PKCδ pathway signaling during EAE evolution.

Testicular steroidogenesis is suppressed during experimental autoimmune encephalomyelitis in rats

Multiple sclerosis (MS) is an autoimmune disease that usually occurs during the reproductive years in both sexes. Many male patients with MS show lower blood testosterone levels, which was also observed in male rats during experimental autoimmune encephalomyelitis (EAE), an animal model of MS. To better understand the causes of decreased testosterone production during EAE, we investigated the expression status of genes and proteins associated with steroidogenesis in the testes. No changes in the number of interstitial cells were observed in EAE animals, but the expression of the insulin-like 3 gene was reduced at the peak of the disease, implying that the Leydig cell functional capacity was affected. Consistent with this finding, the expression of most steroidogenic enzyme genes and proteins was reduced during EAE, including StAR, CYP11A1, CYP17A1 and HSD3B. No signs of testicular inflammation were observed. Recovery of steroidogenesis was observed after injection of hCG, the placental gonadotropin, or buserelin acetate, a gonadotropin-releasing hormone analogue, at the peak of EAE. Together, our results are consistent with the hypothesis that impaired testicular steroidogenesis originates upstream of the testes and that low serum LH is the main cause of decreased testosterone levels during EAE.

Neuroprotective role of galantamine with/without physical exercise in experimental autoimmune encephalomyelitis in rats

AimsThe fact that physical activity besides central cholinergic enhancement contributes in improving neuronal function and spastic plasticity, recommends the use of the anticholinesterase and cholinergic drug galantamine with/without exercise in the management of the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). Materials and methodsSedentary and 14 days exercised male Sprague Dawley rats were subjected to EAE. Hereafter, exercised rats continued on rotarod for 30 min for 17 consecutive days. At the onset of symptoms (day 13), EAE sedentary/exercised groups were subdivided into untreated and post-treated with galantamine. The disease progression was assessed by EAE score, motor performance, and biochemically using cerebrospinal fluid (CSF). Cerebellum and brain stem samples were used for histopathology and immunohistochemistry analysis. Key findingsGalantamine decreased EAE score of sedentary/exercised rats and enhanced their motor performance. Galantamine with/without exercise inhibited CSF levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6), and Bcl-2-associated X protein (Bax), besides caspase-3 and forkhead box P3 (Foxp3) expression in the brain stem. Contrariwise, it has elevated CSF levels of brain derived neurotrophic factor (BDNF) and B-cell lymphoma (Bcl-2) and enhanced remyelination of cerebral neurons. Noteworthy, exercise boosted the drug effect on Bcl-2 and Bax. SignificanceThe neuroprotective effect of galantamine against EAE was associated with anti-inflammatory and anti-apoptotic potentials, along with increasing BDNF and remyelination. It also normalized regulatory T-cells levels in the brain stem. The impact of the add-on of exercise was markedly manifested in reducing neuronal apoptosis.

Compensatory Neuroprotective Response of Thioredoxin Reductase against Oxidative-Nitrosative Stress Induced by Experimental Autoimmune Encephalomyelitis in Rats: Modulation by Theta Burst Stimulation.

Cortical theta burst stimulation (TBS) structured as intermittent (iTBS) and continuous (cTBS) could prevent the progression of the experimental autoimmune encephalomyelitis (EAE). The interplay of brain antioxidant defense systems against free radicals (FRs) overproduction induced by EAE, as well as during iTBS or cTBS, have not been entirely investigated. This study aimed to examine whether oxidative-nitrogen stress (ONS) is one of the underlying pathophysiological mechanisms of EAE, which may be changed in terms of health improvement by iTBS or cTBS. Dark Agouti strain female rats were tested for the effects of EAE and TBS. The rats were randomly divided into the control group, rats specifically immunized for EAE and nonspecifically immuno-stimulated with Complete Freund’s adjuvant. TBS or sham TBS was applied to EAE rats from 14th–24th post-immunization day. Superoxide dismutase activity, levels of superoxide anion (O2•–), lipid peroxidation, glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH), and thioredoxin reductase (TrxR) activity were analyzed in rat spinal cords homogenates. The severity of EAE clinical coincided with the climax of ONS. The most critical result refers to TrxR, which immensely responded against the applied stressors of the central nervous system (CNS), including immunization and TBS. We found that the compensatory neuroprotective role of TrxR upregulation is a positive feedback mechanism that reduces the harmfulness of ONS. iTBS and cTBS both modulate the biochemical environment against ONS at a distance from the area of stimulation, alleviating symptoms of EAE. The results of our study increase the understanding of FRs’ interplay and the role of Trx/TrxR in ONS-associated neuroinflammatory diseases, such as EAE. Also, our results might help the development of new ideas for designing more effective medical treatment, combining neuropsychological with noninvasive neurostimulation–neuromodulation techniques to patients living with MS.

Folate receptor-targeted positron emission tomography of experimental autoimmune encephalomyelitis in rats

BackgroundFolate receptor-β (FR-β) is a cell surface receptor that is significantly upregulated on activated macrophages during inflammation and provides a potential target for folate-based therapeutic and diagnostic agents. FR-β expression in central nervous system inflammation remains relatively unexplored. Therefore, we used focally induced acute and chronic phases of experimental autoimmune encephalomyelitis (EAE) to study patterns of FR-β expression and evaluated its potential as an in vivo imaging target.MethodsFocal EAE was induced in rats using heat-killed Bacillus Calmette-Guérin followed by activation with complete Freund’s adjuvant supplemented with Mycobacterium tuberculosis. The rats were assessed with magnetic resonance imaging and positron emission tomography/computed tomography (PET/CT) at acute (14 days) and chronic (90 days) phases of inflammation. The animals were finally sacrificed for ex vivo autoradiography of their brains. PET studies were performed using FR-β-targeting aluminum [18F]fluoride-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid conjugated folate ([18F]AlF-NOTA-folate, 18F-FOL) and 18 kDa translocator protein (TSPO)-targeting N-acetyl-N-(2-[11C]methoxybenzyl)-2-phenoxy-5-pyridinamine (11C-PBR28). Post-mortem immunohistochemistry was performed using anti-FR-β, anti-cluster of differentiation 68 (anti-CD68), anti-inducible nitric oxide synthase (anti-iNOS), and anti-mannose receptor C-type 1 (anti-MRC-1) antibodies. The specificity of 18F-FOL binding was verified using in vitro brain sections with folate glucosamine used as a blocking agent.ResultsImmunohistochemical evaluation of focal EAE lesions demonstrated anti-FR-β positive cells at the lesion border in both acute and chronic phases of inflammation. We found that anti-FR-β correlated with anti-CD68 and anti-MRC-1 immunohistochemistry; for MRC-1, the correlation was most prominent in the chronic phase of inflammation. Both 18F-FOL and 11C-PBR28 radiotracers bound to the EAE lesions. Autoradiography studies verified that this binding took place in areas of anti-FR-β positivity. A blocking assay using folate glucosamine further verified the tracer’s specificity. In the chronic phase of EAE, the lesion-to-background ratio of 18F-FOL was significantly higher than that of 11C-PBR28 (P = 0.016).ConclusionOur EAE results imply that FR-β may be a useful target for in vivo imaging of multiple sclerosis-related immunopathology. FR-β-targeted PET imaging with 18F-FOL may facilitate the monitoring of lesion development and complement the information obtained from TSPO imaging by bringing more specificity to the PET imaging armamentarium for neuroinflammation.

Cessation of anti-VLA-4 therapy in a focal rat model of multiple sclerosis causes an increase in neuroinflammation

BackgroundPositron emission tomography (PET) can be used for in vivo evaluation of the pathology associated with multiple sclerosis. We investigated the use of longitudinal PET imaging and the 18-kDa translocator protein (TSPO) binding radioligand [18F]GE-180 to detect changes in a chronic multiple sclerosis-like focal delayed-type hypersensitivity experimental autoimmune encephalomyelitis (fDTH-EAE) rat model during and after anti-VLA-4 monoclonal antibody (mAb) treatment. Thirty days after lesion activation, fDTH-EAE rats were treated with the anti-VLA-4 mAb (n = 4) or a control mAb (n = 4; 5 mg/kg, every third day, subcutaneously) for 31 days. Animals were imaged with [18F]GE-180 on days 30, 44, 65, 86 and 142. Another group of animals (n = 4) was used for visualisation the microglia with Iba-1 at day 44 after a 2-week treatment period.ResultsAfter a 2-week treatment period on day 44, there was a declining trend (p = 0.067) in [18F]GE-180-binding in the anti-VLA-4 mAb-treated animals versus controls. However, cessation of treatment for 4 days after a 31-day treatment period increased [18F]GE-180 binding in animals treated with anti-VLA-4 mAb compared to the control group (p = 0.0003). There was no difference between the groups in TSPO binding by day 142.ConclusionsThese results demonstrated that cessation of anti-VLA-4 mAb treatment for 4 days caused a transient rebound increase in neuroinflammation. This highlights the usefulness of serial TSPO imaging in the fDTH-EAE model to better understand the rebound phenomenon.

Prenatal stress-induced sex differences in the incidence and course of experimental autoimmune encephalomyelitis in rats

Aim. The research is aimed at investigating the effect of prenatal stress on the incidence and course of experimental autoimmune encephalomyelitis (EAE) in four-month-old rats, offspring of females with different sensitivity to EAE induction. Methods. The incidence and severity of EAE (duration of latent period (LP)), the maximum level of neurological deficit (KSmax) and the duration of the period from the first to the maximum manifestations of neurological deficit (T)) were analyzed in rats with induced EAE. Results. A decrease in the incidence of EAE in prenatally stressed four-month-old females, whose mothers were sensitive to induction of EAE, was found. Differences in the dynamics of EAE course in males from the control and prenatally stressed group were revealed. Conclusions.The EAE incidence and EAE course traits in four-month-old rats depend on a complex of factors: mother's sensitivity to induction of EAE, prenatal stress and offspring sex.
 Keywords: experimental autoimmune encephalomyelitis, prenatal stress, sex, sensitivity to induction of EAE.

Withdrawn: Effects of Tofacitinib on Tfr/Tfh Balance and Expression of CXCL13 and TGF-β1 in Experimental Autoimmune Encephalomyelitis Rats

The article entitled, “Effects of Tofacitinib on Tfr/Tfh Balance and Expression of CXCL13 and TGF-β1 in Experimental Autoimmune Encephalomyelitis Rats” submitted in CNS & Neurological Disorders - Drug Targets (CNS&NDDT) by Dr. Zuoxiao Li has been withdrawn from the journal in accordance with BSP Editorial Policies.

The possible anti-apoptotic and antioxidant effects of acetyl l-carnitine as an add-on therapy on a relapsing-remitting model of experimental autoimmune encephalomyelitis in rats

Multiple sclerosis (MS) is a progressive inflammatory autoimmune demyelinating disease of the brain and spinal cord. Glucocorticoids (GCs) are the standard treatment of MS, however they have several drawbacks like oxidative stress and apoptosis. This study was designed to evaluate some possible antioxidant, anti-apoptotic and immune modulatory effects of Acetyl-l-carnitine (ALCAR) when used either alone or as an add-on therapy with dexamethasone for treatment of a relapsing-remitting (RR) experimental autoimmune encephalomyelitis (EAE) as a model of MS. This experiment was performed on 50 female Sprague Dawley rats divided into; normal control group, untreated EAE group, EAE group treated by dexamethasone, EAE group treated by ALCAR, and EAE group treated by both dexamethasone and ALCAR. The clinical score of the motor deficit of EAE was recorded daily. At the end of experiment, rats were sacrificed and the brain and spinal cord were processed for assessment of reduced glutathione (GSH), malondialdehyde (MDA) and caspase-3 activity. Histopathological changes and immunohistochemical expression of Bcl-2 and CD4+ T cell were carried out. Combination of both dexamethasone and ALCAR provided marked antioxidant and anti-apoptotic effects represented by significant decrease in MDA, caspase-3 and significant increase in GSH, Bcl-2 expression, and it also exhibited marked immunosuppressive effect represented by significant decrease in CD4+ T cells expression with significant improvement in clinical outcome when compared to untreated EAE group or to dexamethasone treated group. These findings pave the way for using ALCAR as an adjuvant therapy during long-term use of dexamethasone in MS.

A novel PADRE-Kv1.3 vaccine effectively induces therapeutic antibodies and ameliorates experimental autoimmune encephalomyelitis in rats

Previous studies have confirmed that selective blockade of Kv1.3 channels could modulate the activities of pathogenic T cells and microglia/macrophages, which play key roles in experimental autoimmune encephalomyelitis (EAE). In this study, we designed an anti-Kv1.3 vaccine (PADRE-Kv1.3) to explore its protective role in EAE rat models. When the vaccine was applied in EAE rats, clinical scores and several staining techniques were used to evaluate the severity of the disease. T cell subtypes and related cytokines, as well as microglia/macrophage activation were assayed through flow cytometry, qRT-PCR or immunofluorescence staining, respectively. We herein showed that rats and mice developed high titers of anti-Kv1.3 antibodies and appeared no abnormal manifestations after the PADRE-Kv1.3 vaccine treatment. In EAE models, the vaccine treatment effectively alleviated the clinical severity and lessened pathological damages in the central nervous system (CNS). In addition, we found the vaccine significantly decreased the number of pathogenic T cells (Th17 and IFN-γ–producing T cells) and the production of related pro-inflammatory cytokines (IL-17A, IFN-γ and IL-1β), but increased the number of protective T subsets (CD4+IL-10+ T cells and Treg cells) in the spleen or CNS. Moreover, the infiltration of microglia/macrophages significantly reduced and these cells shifted toward anti-inflammatory M2 subtype in the CNS after the vaccine treatment. Thus, we demonstrated that the PADRE-Kv1.3 vaccine could induce therapeutic anti-Kv1.3 antibodies and ameliorate EAE in rats effectively and safely, which provides a new field of vision for the protection and therapy of multiple sclerosis.

Therapeutic Potential of Pien Tze Huang on Experimental Autoimmune Encephalomyelitis Rat.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). There is still lack of commercially viable treatment currently. Pien Tze Huang (PZH), a traditional Chinese medicine, has been proved to have anti-inflammatory, neuroprotective, and immunoregulatory effects. This study investigated the possible therapeutic effects of PZH on experimental autoimmune encephalomyelitis (EAE) rats, a classic animal model of MS. Male Lewis rats were immunized with myelin basic protein (MBP) peptide to establish an EAE model and then treated with three doses of PZH. Clinical symptoms, organ coefficient, histopathological features, levels of proinflammatory cytokines, and chemokines as well as MBP and Olig2 were analyzed. The results indicated that PZH ameliorated the clinical severity of EAE rats. It also remarkably reduced inflammatory cell infiltration in the CNS of EAE rats. Furthermore, the levels of IL-17A, IL-23, CCL3, and CCL5 in serum and the CNS were significantly decreased; the p-P65 and p-STAT3 levels were also downregulated in the CNS, while MBP and Olig2 in the CNS of EAE rats had a distinct improvement after PZH treatment. In addition, PZH has no obvious toxicity at the concentration of 0.486 g/kg/d. This study demonstrated that PZH could be used to treat MS.

Neuroprotective arylpiperazine dopaminergic/serotonergic ligands suppress experimental autoimmune encephalomyelitis in rats

Arylpiperazine-based dopaminergic/serotonergic ligands exert neuroprotective activity. We examined the effect of arylpiperazine D2 /5-HT1A ligands, N-{4-[2-(4-phenyl-piperazin-1-yl)-ethyl}-phenyl]-picolinamide (6a) and N-{3-[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-picolinamide (6b), in experimental autoimmune encephalomyelitis (EAE), a model of neuroinflammation. Both compounds (10mg/kg i.p.) reduced EAE clinical signs in spinal cord homogenate-immunized Dark Agouti rats. Compound 6b was more efficient in delaying the disease onset and reducing the maximal clinical score, which correlated with its higher affinity for D2 and 5-HT1A receptors. The protection was retained if treatment was limited to the effector (from day 8 onwards), but not the induction phase (day 0-7) of EAE. Compound 6b reduced CNS immune infiltration and expression of mRNA encoding the proinflammatory cytokines tumor necrosis factor, IL-6, IL-1, and GM-CSF, TH 1 cytokine IFN-γ, TH 17 cytokine IL-17, as well as the signature transcription factors of TH 1 (T-bet) and TH 17 (RORγt) cells. Arylpiperazine treatment reduced apoptosis and increased the activation of anti-apoptotic mediators Akt and p70S6 kinase in the CNS of EAE animals. The invitro treatment with 6b protected oligodendrocyte cell line OLN-93 and neuronal cell line PC12 from mitogen-activated normal T cells or myelin basic protein-activated encephalitogenic T cells. In conclusion, arylpiperazine dopaminergic/serotonergic ligands suppress EAE through a direct neuroprotective action and decrease in CNS inflammation. Arylpiperazine dopaminergic/serotonergic ligands reduce neurological symptoms of acute autoimmune encephalomyelitis in rats without affecting the activation of autoreactive immune response, through mechanisms involving a decrease in CNS immune infiltration, as well as direct protection of CNS from immune-mediated damage. These data indicate potential usefulness of arylpiperazine-based compounds in the treatment of neuroinflammatory disorders such as multiple sclerosis.

Peptide-functionalized polymeric nanoparticles for active targeting of damaged tissue in animals with experimental autoimmune encephalomyelitis

Increased permeability of blood vessels is an indicator for various injuries and diseases, including multiple sclerosis (MS), of the central nervous system. Nanoparticles have the potential to deliver drugs locally to sites of tissue damage, reducing the drug administered and limiting associated side effects, but efficient accumulation still remains a challenge. We developed peptide-functionalized polymeric nanoparticles to target blood clots and the extracellular matrix molecule nidogen, which are associated with areas of tissue damage. Using the induction of experimental autoimmune encephalomyelitis in rats to provide a model of MS associated with tissue damage and blood vessel lesions, all targeted nanoparticles were delivered systemically. In vivo data demonstrates enhanced accumulation of peptide functionalized nanoparticles at the injury site compared to scrambled and naive controls, particularly for nanoparticles functionalized to target fibrin clots. This suggests that further investigations with drug laden, peptide functionalized nanoparticles might be of particular interest in the development of treatment strategies for MS.

Oral Administration of Lactococcus lactis Expressing Synthetic Genes of Myelin Antigens in Decreasing Experimental Autoimmune Encephalomyelitis in Rats.

BackgroundMultiple sclerosis is a human autoimmunological disease that causes neurodegeneration. One of the potential ways to stop its development is induction of oral tolerance, whose effect lies in decreasing immune response to the fed antigen. It was shown in animal models that administration of specific epitopes of the three main myelin proteins – myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), and proteolipid protein (PLP) – results in induction of oral tolerance and suppression of disease symptoms. Use of bacterial cells to produce and deliver antigens to gut mucosa seems to be an attractive method for oral tolerance induction in treatment of diseases with autoimmune background.Material/MethodsSynthetic genes of MOG35-55, MBP85-97, and PLP139-151 myelin epitopes were generated and cloned in Lactococcus lactis under a CcpA-regulated promoter. The tolerogenic effect of bacterial preparations was tested on experimental autoimmune encephalomyelitis, which is the animal model of MS. EAE was induced in rats by intradermal injection of guinea pig spinal cord homogenate into hind paws.ResultsRats were administered preparations containing whole-cell lysates of L. lactis producing myelin antigens using different feeding schemes. Our study demonstrates that 20-fold, but not 4-fold, intragastric administration of autoantigen-expressing L. lactis cells under specific conditions reduces the clinical symptoms of EAE in rats.ConclusionsThe present study evaluated the use of myelin antigens produced in L. lactis in inhibiting the onset of experimental autoimmune encephalomyelitis in rats. Obtained results indicate that application of such recombinant cells can be an attractive method of oral tolerance induction.

Actively Induced Experimental Autoimmune Encephalomyelitis in Rats.

The rat and especially a number of inbred rat strains are very well suited for modeling multiple sclerosis (MS). Experimental autoimmune encephalomyelitis (EAE), the model of MS, can be induced by active or passive immunization. Active immunization can be performed with different myelin proteins or peptides thereof. Passive immunization is performed by transfer of myelin-specific T cells. Most known is EAE induced with myelin basic protein (MBP) in LEW (RT1(l)) rats that results in monophasic disease and EAE induced with myelin oligodendrocyte glycoprotein (MOG) in DA (RT1(av1)) rats that leads to relapsing remitting or chronic disease. Depending on the selected inbred rat strain, the immunogen and adjuvant used, different disease courses and pathologies can be induced that mimic different aspects of MS.

Expression pattern of the endoplasmic reticulum stress protein gp96 in monophasic and chronic relapsing form of experimental autoimmune encephalomyelitis in rats.

Gp96 is the endoplasmic reticulum (ER)-resident molecular chaperone, which is involved in the correction of unfolded proteins, in the activation of proteasome-dependent ER-associated degradation of the misfolded proteins, and in activation of the protein translation that modulates polypeptide traffic into the ER. Furthermore, owing to its peptide chaperone capacity and ability to interact with professional antigen-presenting cells, as well as with growth factors, integrins and Toll-like receptors, it is also endowed with crucial immunological functions acting as a "danger signal" to the innate and adaptive immunity. Considering these properties, in the present study the tissue expression of gp96 was examined during the monophasic and chronic relapsing form of experimental autoimmune encephalomyelitis (CR-EAE), induced in genetically susceptible DA rats by subcutaneous injection of myelin basic protein (MBP) or bovine brain homogenate in complete Freund's adjuvant (CFA). Immunohistochemical analyses were done in periods of attacks and remissions of EAE, and the results were compared with findings in intact rats and those treated only with CFA. The data revealed that the constitutive gp96 expression, found in several neurons and glial cells in the brain and spinal cord of intact animals, significantly diminished during the attacks of CR-EAE. On the contrary, the remission of disease was followed by high upregulation of gp96, mainly in the oligodendrocytes within the white matter, in the neurons of the hippocampal area, as well as in the motoneurons of lumbar spinal cord, suggesting that gp96 might be involved in proteostasis and immune-related pathways linked with the reparative processes in the CNS.

Therapeutic gene silencing with siRNA for IL-23 but not for IL-17 suppresses the development of experimental autoimmune encephalomyelitis in rats

Gene silencing with siRNAs is important as a therapeutic tool in autoimmune diseases. In this study, we administered siRNAs specific for cytokines that may be involved in pathogenesis of experimental autoimmune encephalomyelitis (EAE). siRNA specific for IL-23p19 (siRNA-IL-23) suppressed EAE almost completely, whereas siRNA-IL-17A did not modulate the clinical course. Flow cytometric analysis revealed that siRNA-IL-23 significantly reduced the proportion of both IFN-γ+IL-17− Th1 and IFN-γ−IL-17+ Th17 cells in the spinal cord. Consistent with this finding, siRNA-IL-23 treatment downregulated IL-12, IL-17 and IL-23 mRNAs. These findings indicate that IL-23, but not IL-17, play an important role in the development of EAE.

Neuroprotective and memory enhancing properties of a dual agonist of the FGF receptor and NCAM

The fibroblast growth factor receptor (FGFR) plays a vital role in the development of the nervous system regulating a multitude of cellular processes. One of the interaction partners of the FGFR is the neural cell adhesion molecule (NCAM), which is known to play an important role in neuronal development, regeneration and synaptic plasticity. Thus, simultaneous activation of FGFR- and NCAM-mediated signaling pathways may be expected to affect processes underlying neurodegenerative diseases.We here report the identification of a peptide compound, Enreptin, capable of interacting with both FGFR and NCAM. We demonstrate that this dual specificity agonist induces phosphorylation of FGFR and differentiation and survival of primary neurons in vitro, and that these effects are inhibited by abrogation of both NCAM and FGFR signaling pathways. Furthermore, Enreptin crosses the blood–brain barrier after subcutaneous administration, enhances long-term memory in normal mice and ameliorates memory deficit in mice with induced brain inflammation. Moreover, Enreptin reduces cognitive impairment and neuronal death induced by Aβ25–35 in a rat model of Alzheimer's disease, and reduces the mortality rate and clinical signs of experimental autoimmune encephalomyelitis in rats. Thus, Enreptin is an attractive candidate for the treatment of neurological diseases.