A model of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice for the characterisation of intervention therapies

AAV1.NT3 gene therapy mitigates the severity of autoimmune encephalomyelitis in the mouse model for multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated chronic inflammatory and neurodegenerative disease of the central nervous system (CNS) affecting more than 2.5 million patients worldwide. Chronic demyelination in the CNS has an important role in perpetuating axonal loss and increases difficulty in promoting remyelination. Therefore, regenerative, and neuroprotective strategies are essential to overcome this impediment to rescue axonal integrity and function. Neurotrophin 3 (NT-3) has immunomodulatory and anti-inflammatory properties, in addition to its well-recognized function in nervous system development, myelination, neuroprotection, and regeneration. For this study, scAAV1.tMCK.NT-3 was delivered to the gastrocnemius muscle of experimental autoimmune encephalomyelitis (EAE) mice, the chronic relapsing mouse model of MS, at 3 weeks post EAE induction. Measurable NT-3 levels were found in serum at 7-weeks post gene delivery. The treated cohort showed improved clinical scores and performed significantly better in rotarod, and grip strength tests compared to their untreated counterparts. Histopathologic studies showed improved remyelination and axon protection. These data correlated with reduced expression of the pro-inflammatory cytokines in brain and spinal cord, and increased percentage of regulatory T cells in the spleens and lymph nodes. Collectively, these findings demonstrate the translational potential of AAV-delivered NT-3 for chronic progressive MS.

A Standardized Extract of Zingiber officinale Roscoe Regulates Clinical and Biological Outcomes in Two Different EAE Mouse Models

Background/Objectives: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by demyelination and neuronal damage. Current MS therapies are unsatisfactory, and new therapies are encouraged. A correlation between nutritional intake and MS has been speculated. Supplementation of approved immunomodulatory therapy with herbal medicines possessing antioxidant and anti-inflammatory activities could provide benefits to MS patients. Ginger is one of the most widely consumed dietary supplements in the world, commonly used in traditional medicine. Studies demonstrated that ginger may also be beneficial in the management of neurodegenerative diseases. The aim of this study is to investigate the MS therapeutic potential of ginger. Methods: A standardized Zingiber officinale Roscoe extract (ZOE) was orally administered for 14 days. Two experimental autoimmune encephalomyelitis (EAE) models in mice were used. The PLP139-151-EAE relapsing-remitting model and MOG35-55-EAE chronic model. Clinical score, von Frey, hot plate, and rotarod tests were used for behavioral tests. ELISA and Western blotting were used to measure cytokines levels. Evans Blue content was determined spectrophotometrically. Results: ZOE attenuated motor disability and pain hypersensitivity in both models had no effect on body weight loss. ZOE reduced the blood-brain barrier (BBB) permeability in the PLP-EAE models and reduced levels of circulating cytokines (Il-6, IL-17) in the MOG-EAE model. ZOE attenuated spinal cytokines overexpression in both models. Conclusions: ZOE improves EAE symptoms and attenuates the proinflammatory response in both models, representing a promising nutraceutical support to the conventional therapeutic approach to MS.

Complete Freund's adjuvant as a confounding factor in multiple sclerosis research

Complete Freund's adjuvant (CFA) is used as a standard adjuvant for the induction of experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model in multiple sclerosis studies. Still, CFA induces glial activation and neuroinflammation on its own and provokes pain. In addition, as CFA contains Mycobacteria, an immune response against bacterial antigens is induced in parallel to the response against central nervous system antigens. Thus, CFA can be considered as a confounding factor in multiple sclerosis-related studies performed on EAE. Here, we discuss the effects of CFA in EAE in detail and present EAE variants induced in experimental animals without the use of CFA. We put forward CFA-free EAE variants as valuable tools for studying multiple sclerosis pathogenesis and therapeutic approaches.

Metformin treatment reduces inflammation, dysmyelination and disease severity in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammation, death or damage of oligodendrocytes, and axonal degeneration. Current MS treatments are non-curative, associated with undesired side-effects, and expensive, highlighting the need for expanded therapeutic options for patients. There is great interest in developing interventions using drugs or therapeutics to reduce symptom onset and protect pre-existing myelin. Metformin is a well-tolerated drug used to treat Type 2 diabetes that has pleiotropic effects in the central nervous system (CNS), including reducing inflammation, enhancing oligodendrogenesis, increasing the survival/proliferation of neural stem cells (NSCs), and increasing myelination. Here, we investigated whether metformin administration could improve functional outcomes, modulate oligodendrocyte precursor cells (OPCs), and reduce inflammation in a well-established mouse model of MS- experimental autoimmune encephalomyelitis (EAE). Male and female mice received metformin treatment at the time of EAE induction ("acute") or upon presentation of disease symptoms ("delayed"). We found that acute metformin treatment improved functional outcomes, concomitant with reduced microglia numbers and decreased dysmyelination. Conversely, delayed metformin treatment did not improve functional outcomes. Our findings reveal that metformin administration can improve EAE outcomes when administered before symptom onset in both sexes.

Characterization of Depression- and Anxiety-Like Behaviours in a Mouse Model of Relapsing-Remitting Multiple Sclerosis

Relapsing-remitting multiple sclerosis (RRMS) is an autoimmune neurological disease and is the most common subtype of MS. In addition, it is associated with the development of depression and anxiety. To date, depressive- and anxiety-like behaviours were only studied using models of progressive MS, which causes severe motor alterations. Thus, we sought to standardise the depressive and anxiety-like behaviours in an RRMS model induced by experimental autoimmune encephalomyelitis (RR-EAE) in mice. The RR-EAE model was induced in C57BL/6 female mice using myelin oligodendrocyte glycoprotein (MOG35-55) antigen and Quillaja saponin (Quil A) as an adjuvant. The immunisation of RR-EAE did not induce locomotor alteration but caused relapsing-remitting induction of clinical scores in mice until 35 post-immunization (p.i.). Also, increased levels of tumour necrosis factor alpha (TNF-α), astrocyte marker (GFAP), and microglial markers (IBA-1) were detected in the prefrontal cortex at 35 p.i. of RR-EAE. In the open field test, RR-EAE mice showed decreased time spent at the centre and sniffing behaviour (at days 21 and 34 p.i.). Also, on day 35 p.i. the RR-EAE group spent less time in the open arms and had decreased open-arm entries compared to control mice in the elevated plus maze (EPM) test, confirming the anxiety-like behaviour. At day 36° p.i. in the tail suspension test, mice showed depression-like behaviour with decreased latency time and increased immobility time. Thus, the RR-EAE model mimics the neuroinflammatory and behavioural features of the RRMS, including depression- and anxiety-like symptoms.

Posttranscriptional Regulation of Gene Expression Participates in the Myelin Restoration in Mouse Models of Multiple Sclerosis: Antisense Modulation of HuR and HuD ELAV RNA Binding Protein

Neuropathic pain is the most difficult-to-treat pain syndrome in multiple sclerosis. Evidence relates neuropathic pain to demyelination, which often originates from unresolved neuroinflammation or altered immune response. Posttranscriptional regulation of gene expression might play a fundamental role in the regulation of these processes. The ELAV RNA-binding proteins HuR and HuD are involved in the promotion of inflammatory phenomena and in neuronal development and maintenance, respectively. Thus, the aim of this study was to investigate the role of HuR and HuD in demyelination-associated neuropathic pain in the mouse experimental autoimmune encephalomyelitis (EAE) model. HuR resulted overexpressed in the spinal cord of MOG_35-55-EAE and PLP_139-151-EAE mice and was detected in CD11b + cells. Conversely, HuD was largely downregulated in the MOG-EAE spinal cord, along with GAP43 and neurofilament H, while in PLP-EAE mice, HuD and neuronal markers remained unaltered. Intranasal antisense oligonucleotide (ASO) delivery to knockdown HuR, increased myelin basic protein expression, and Luxol Fast Blue staining in both EAE models, an indication of increased myelin content. These effects temporally coincided with attenuation of pain hypersensitivity. Anti-HuR ASO increased the expression of HuD in GAP43-expressing cells and promoted a HuD-mediated neuroprotective activity in MOG-EAE mice, while in PLP-EAE mice, HuR silencing dampened pro-inflammatory responses mediated by spinal microglia activation. In conclusion, anti-HuR ASO showed myelin protection at analgesic doses with multitarget mechanisms, and it deserves further consideration as an innovative agent to counteract demyelination in neuropathic pain states.

Early derangement of axonal mitochondria occurs in a mouse model of progressive but not relapsing-remitting multiple sclerosis

INTRODUCTION

Derangement of axonal mitochondrial bioenergetics occurs during progressive multiple sclerosis (PMS). However, whether this is a delayed epiphenomenon or an early causative event of disease progression waits to be understood. Answering this question might further our knowledge of mechanisms underlying neurobiology of PMS and related therapy.

METHODS

MOG_35-55-immunized NOD and PLP_139-151-immunized SJL female mice were adopted as models of progressive or relapsing-remitting experimental autoimmune encephalomyelitis (EAE), respectively. Multiple parameters of mitochondrial homeostasis were analyzed in the mouse spinal cord during the early asymptomatic stage, also evaluating the effects of scavenging mitochondrial reactive oxygen species with Mito-TEMPO.

RESULTS

Almost identical lumbar spinal cord immune infiltrates consisting of Th1 cells and neutrophils without B and Th17 lymphocytes occurred early upon immunization in both mouse strains. Still, only NOD mice showed axon-restricted dysregulation of mitochondrial homeostasis, with reduced mtDNA contents and increased cristae area. Increased expression of mitochondrial respiratory complex subunits Nd2, Cox1, Atp5d, Sdha also exclusively occurred in lumbar spinal cord of NOD and not SJL mice. Accordingly, in this region genes regulating mitochondrial morphology (Opa1, Mfn1, Mfn2 and Atp5j2) and mitochondriogenesis (Pgc1α, Foxo, Hif-1α and Nrf2) were induced early upon immunization. A reduced extent of mitochondrial derangement occurred in the thoracic spinal cord. Notably, the mitochondrial radical scavenger Mito-TEMPO reduced H₂O₂ content and prevented both mtDNA depletion and cristae remodeling, having no effects on dysregulation of mitochondrial transcriptome.

DISCUSSION

We provide here the first evidence that axonal-restricted derangement of mitochondrial homeostasis already occurs during the asymptomatic state exclusively in a mouse model of PMS. Data further our understanding of mechanisms related to EAE progression, and point to very early axonal mitochondrial dysfunction as central to the neuropathogenesis of MS evolution.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

In-Depth Characterization of Somatic and Orofacial Sensitive Dysfunctions and Interfering-Symptoms in a Relapsing-Remitting Experimental Autoimmune Encephalomyelitis Mouse Model

Among the many symptoms (motor, sensory, and cognitive) associated with multiple sclerosis (MS), chronic pain is a common disabling condition. In particular, neuropathic pain symptoms are very prevalent and debilitating, even in early stages of the disease. Unfortunately, chronic pain still lacks efficient therapeutic agents. Progress is needed (i) clinically by better characterizing pain symptoms in MS and understanding the underlying mechanisms, and (ii) preclinically by developing a more closely dedicated model to identify new therapeutic targets and evaluate new drugs. In this setting, new variants of experimental autoimmune encephalomyelitis (EAE) are currently developed in mice to exhibit less severe motor impairments, thereby avoiding confounding factors in assessing pain behaviors over the disease course. Among these, the optimized relapsing-remitting EAE (QuilA-EAE) mouse model, induced using myelin oligodendrocyte glycoprotein peptide fragment (35–55), pertussis toxin, and quillaja bark saponin, seems very promising. Our study sought (i) to better define sensitive dysfunctions and (ii) to extend behavioral characterization to interfering symptoms often associated with pain during MS, such as mood disturbances, fatigue, and cognitive impairment, in this optimized QuilA-EAE model. We made an in-depth characterization of this optimized QuilA-EAE model, describing for the first time somatic thermal hyperalgesia associated with mechanical and cold allodynia. Evaluation of orofacial pain sensitivity showed no mechanical or thermal allodynia. Detailed evaluation of motor behaviors highlighted slight defects in fine motor coordination in the QuilA-EAE mice but without impact on pain evaluation. Finally, no anxiety-related or cognitive impairment was observed during the peak of sensitive symptoms. Pharmacologically, as previously described, we found that pregabalin, a treatment commonly used in neuropathic pain patients, induced an analgesic effect on mechanical allodynia. In addition, we showed an anti-hyperalgesic thermal effect on this model. Our results demonstrate that this QuilA-EAE model is clearly of interest for studying pain symptom development and so could be used to identify and evaluate new therapeutic targets. The presence of interfering symptoms still needs to be further characterized.

TNFα in MS and Its Animal Models: Implications for Chronic Pain in the Disease

Multiple Sclerosis (MS) is a debilitating autoimmune disease often accompanied by severe chronic pain. The most common type of pain in MS, called neuropathic pain, arises from disease processes affecting the peripheral and central nervous systems. It is incredibly difficult to study these processes in patients, so animal models such as experimental autoimmune encephalomyelitis (EAE) mice are used to dissect the complex mechanisms of neuropathic pain in MS. The pleiotropic cytokine tumor necrosis factor α (TNFα) is a critical factor mediating neuropathic pain identified by these animal studies. The TNF signaling pathway is complex, and can lead to cell death, inflammation, or survival. In complex diseases such as MS, signaling through the TNFR1 receptor tends to be pro-inflammation and death, whereas signaling through the TNFR2 receptor is pro-homeostatic. However, most TNFα-targeted therapies indiscriminately block both arms of the pathway, and thus are not therapeutic in MS. This review explores pain in MS, inflammatory TNF signaling, the link between the two, and how it could be exploited to develop more effective TNFα-targeting pain therapies.

Recombinant myelin oligodendrocyte glycoprotein quality modifies evolution of experimental autoimmune encephalitis in macaques

Experimental autoimmune encephalitis (EAE) is a well-recognized model for the study of human acquired demyelinating diseases (ADD), a group of inflammatory disorders of the central nervous system (CNS) characterized by inflammation, myelin loss, and neurological impairment of variable severity. In rodents, EAE is typically induced by active immunization with a combination of myelin-derived antigen and a strong adjuvant as complete Freund's adjuvant (CFA), containing components of the mycobacterial wall, while myelin antigen alone or associated with other bacterial components, as lipopolysaccharides (LPS), often fails to induce EAE. In contrast to this, EAE can be efficiently induced in non-human primates by immunization with the recombinant human myelin oligodendrocyte glycoprotein (rhMOG), produced in Escherichia coli (E. coli), purified and formulated with incomplete Freund's adjuvant (IFA), which lacks bacterial elements. Here, we provide evidence indicating how trace amounts of bacterial contaminants within rhMOG may influence the course and severity of EAE in the cynomolgus macaque immunized with rhMOG/IFA. The residual amount of E. coli contaminants, as detected with mass spectrometry within rhMOG protein stocks, were found to significantly modulate the severity of clinical, radiological, and histologic hallmarks of EAE in macaques. Indeed, animals receiving the purest rhMOG showed milder disease severity, increased numbers of remissions, and reduced brain damage. Histologically, these animals presented a wider diversity of lesion types, including changes in normal-appearing white matter and prephagocytic lesions. Non-human primates EAE model with milder histologic lesions reflect more accurately ADD and permits to study of the pathogenesis of disease initiation and progression.

Targeting the RNA-Binding Protein HuR Alleviates Neuroinflammation in Experimental Autoimmune Encephalomyelitis: Potential Therapy for Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune inflammatory and neurodegenerative disease of the central nervous system characterized by demyelination, axonal loss, and motor dysfunction. Activated microglia are associated with the destruction of myelin in the CNS. Activated microglia produce cytokines and proinflammatory factors, favoring neuroinflammation, myelin damage, and neuronal loss, and it is thought to be involved in the disease pathogenesis. The present study investigated the role of post-transcriptional regulation of gene expression on the neuroinflammation related to experimental autoimmune encephalomyelitis (EAE) in mice, by focusing on HuR, an RNA-binding protein involved in inflammatory and immune phenomena. Spinal cord sections of EAE mice showed an increased HuR immunostaining that was abundantly detected in the cytoplasm of activated microglia, a pattern associated with its increased activity. Intrathecal administration of an anti-HuR antisense oligonucleotide (ASO) decreased the proinflammatory activated microglia, inflammatory infiltrates, and the expression of the proinflammatory cytokines IL-1β, TNF-α, and IL-17, and inhibited the activation of the NF-κB pathway. The beneficial effect of anti-HuR ASO in EAE mice corresponded also to a decreased permeability of the blood-brain barrier. EAE mice showed a reduced spinal CD206 immunostaining that was restored by anti-HuR ASO, indicating that HuR silencing promotes a shift to the anti-inflammatory and regenerative microglia phenotype. Mice that received anti-HuR ASO exhibited improved EAE-related motor dysfunction, pain hypersensitivity, and body weight loss. Targeting HuR might represent an innovative and promising perspective to control neurological disturbances in MS patients.

Chronic mechanical hypersensitivity in experimental autoimmune encephalomyelitis is regulated by disease severity and neuroinflammation

Chronic pain severely affects quality of life in more than half of people living with multiple sclerosis (MS). A commonly-used model of MS, experimental autoimmune encephalomyelitis (EAE), typically presents with hindlimb paralysis, neuroinflammation and neurodegeneration. However, this paralysis may hinder the use of pain behavior tests, with no apparent hypersensitivity observed post-peak disease. We sought to adapt the classic actively-induced EAE model to optimize its pain phenotype. EAE was induced with MOG_35-55/CFA and 100-600 ng pertussis toxin (PTX), and mice were assessed for mechanical, cold and thermal sensitivity over a 28-day period. Spinal cord tissue was collected at 14 and 28 days post-injection to assess demyelination and neuroinflammation. Only mice treated with 100 ng PTX exhibited mechanical hypersensitivity. Hallmarks of disease pathology, including demyelination, immune cell recruitment, cytokine expression, glial activation, and neuronal damage were higher in EAE mice induced with moderate (200 ng) doses of pertussis toxin, compared to those treated with low (100 ng) levels. Immunostaining demonstrated activated astrocytes and myeloid/microglial cells in both EAE groups. These results indicate that a lower severity of EAE disease may allow for the study of pain behaviors while still presenting with disease pathology. By using this modified model, researchers may better study the mechanisms underlying pain.

P-glycoprotein Inhibitor Tariquidar Potentiates Efficacy of Astragaloside IV in Experimental Autoimmune Encephalomyelitis Mice

ATP-binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), often reduce drug efficacy and are the major cause of drug resistance. Astragaloside IV (ASIV), one of the bioactive saponins isolated from Astragalus membranaceus, has been demonstrated to alleviate the progression of experimental autoimmune encephalomyelitis (EAE) in mice, an animal model for multiple sclerosis (MS). In the present study, we found for the first time that ASIV induced the upregulation of P-gp and BCRP in the central nervous system (CNS) microvascular endothelial cells of EAE mice. Further study disclosed that tariquidar, a P-gp inhibitor, could facilitate the penetration of ASIV into CNS. On bEnd.3 cells, a mouse brain microvascular endothelial cell line, tariquidar benefited the net uptake and transport of ASIV. Additional molecular docking experiment suggested that ASIV might be a potential substrate of P-gp. In EAE mice, tariquidar was demonstrated to enhance the efficacy of ASIV, as shown by attenuated clinical symptom and reduced incidence rate as well as mitigated inflammatory infiltration and decreased demyelination in the CNS. Collectively, our findings implicate that P-gp inhibitor can promote the therapeutic efficacy of ASIV on EAE mice, which may boost its clinical usage together with ASIV in the therapy of MS.

Acylated and deacylated quillaja saponin-21 adjuvants have opposite roles when utilized for immunization of C57BL/6 mice model with MOG35-55 peptide

BACKGROUND

The majority of patients with multiple sclerosis (MS) suffer from central neuropathic pain (CNP). Using experimental autoimmune encephalomyelitis (EAE) model, only a few experiments were performed to assess pain behaviors in MS. To address this issue, complete Freund's adjuvant (CFA) was replaced with an acylated triterpene glycoside saponin adjuvant named quillaja saponin-21 (QS-21) to develop CNP in the EAE mouse model. The deacylated form of QS-21, named QT-0101, has been suggested to have an immunomodulatory effect. Thus, QT-0101 was used as a vaccine adjuvant to modulate the immune system against myelin oligodendrocyte glycoprotein (MOG35-55) antigen.

METHODS

In this study, C57BL/6 mice, except for mice in the negative control (PBS) and MOG groups, were divided into three groups and immunized by MOG35-55 emulsified with CFA, QS-21, or QT-0101 adjuvants, respectively. Thermal hyperalgesia, as a CNP clinical manifestation, through the Hot Plate test and the clinical signs, was assessed for 60 days after immunization. On days 21 and 60, mice were sacrificed and the frequency of TCD4⁺, TCD8⁺, IL-17⁺, IL-4⁺, and CD25⁺/FoxP3⁺ cells population in the total splenocytes population was assessed by flow cytometry. Infiltration of Leukocytes into the brain and demyelination of white matter were also evaluated by histopathologic studies.

RESULTS

Our results revealed that unlike the MOG+QT-0101 group, the MOG+QS-21 and MOG+CFA groups represented clinical symptoms that mimic the mild relapsing-remitting and monophasic models, respectively. Thermal hyperalgesia, as a CNP clinical manifestation, developed in the bilateral hind paws in the MOG+CFA and MOG+QS-21 mice groups during the onset of neurologic deficits, but it is maintained until completion of the study only in MOG+QS-21 mice group. The frequency of TCD4⁺, TCD8⁺ and IL-17⁺ cells population in the MOG+QS-21 and MOG+CFA mice groups, as well as IL-4⁺ and CD25⁺/Foxp3⁺ cells population in the MOG+QT-0101 mice group, significantly increased in comparison with the PBS mice group. Infiltration of inflammatory cells increased significantly in the MOG+QS-21 and MOG+CFA mice groups compared with the PBS mice group. Demyelination of white matter was identified significantly only in the MOG+CFA mice group compared with the PBS mice group.

CONCLUSION

These results showed that QS-21 is a suitable adjuvant for the establishment of a mild relapsing-remitting EAE model for CNP development and open a new avenue to future pre-clinical and clinical research studies related to CNP treatment. Nevertheless, QT-0101 seems to have the potential to act as a vaccine adjuvant with immunomodulatory property against auto-antigens.

Exploiting the Therapeutic Potential of Endogenous Immunomodulatory Systems in Multiple Sclerosis-Special Focus on the Peroxisome Proliferator-Activated Receptors (PPARs) and the Kynurenines

Multiple sclerosis (MS) is a progressive neurodegenerative disease, characterized by autoimmune central nervous system (CNS) demyelination attributable to a disturbed balance between encephalitic T helper 1 (Th1) and T helper 17 (Th17) and immunomodulatory regulatory T cell (Treg) and T helper 2 (Th2) cells, and an alternatively activated macrophage (M2) excess. Endogenous molecular systems regulating these inflammatory processes have recently been investigated to identify molecules that can potentially influence the course of the disease. These include the peroxisome proliferator-activated receptors (PPARs), PPARγ coactivator-1alpha (PGC-1α), and kynurenine pathway metabolites. Although all PPARs ameliorate experimental autoimmune encephalomyelitis (EAE), recent evidence suggests that PPARα, PPARβ/δ agonists have less pronounced immunomodulatory effects and, along with PGC-1α, are not biomarkers of neuroinflammation in contrast to PPARγ. Small clinical trials with PPARγ agonists have been published with positive results. Proposed as immunomodulatory and neuroprotective, the therapeutic use of PGC-1α activation needs to be assessed in EAE/MS. The activation of indolamine 2,3-dioxygenase (IDO), the rate-limiting step of the kynurenine pathway of tryptophan (Trp) metabolism, plays crucial immunomodulatory roles. Indeed, Trp metabolites have therapeutic relevance in EAE and drugs with structural analogy to kynurenines, such as teriflunomide, are already approved for MS. Further studies are required to gain deeper knowledge of such endogenous immunomodulatory pathways with potential therapeutic implications in MS.

Immunomodulatory effects of a rationally designed peptide mimetic of human IFNβ in EAE model of multiple sclerosis

The efficiency of interferon beta (IFNβ)-based drugs is considerably limited due to their undesirable properties, especially high immunogenicity. In this study, for the first time we investigated the impact of a computationally designed peptide mimetic of IFNβ, called MSPEP27, in the animal model of MS. A peptide library was constructed using the Rosetta program based on the predominant IFNAR1-binding site of IFNβ. Molecular docking studies were carried out using ClusPro and HADDOCK tools. The GROMACS package was subsequently used for molecular dynamics (MD) simulations. Validation of peptide-receptor interaction was carried out using intrinsic fluorescence measurements. To explore in silico findings further, experimental autoimmune encephalomyelitis (EAE) was induced by subcutaneous immunization of myelin oligodendrocyte glycoprotein (MOG35-55). Mice were then separated into distinct groups and intravenously received 10 or 20mgkg^-1 of MSPEP27 or IFNβ. The inflammatory mediators were monitored by immunohistochemistry (IL17, CD11b, CD45), quantitative real-time PCR (MMP2, MMP9, TIMP-1) and enzyme-linked immunosorbent assay (IL1β, TNFα) methods. Among the library of tolerated peptides, MSPEP27, a peptide with favorable physicochemical properties, was chosen for further experiments. This peptide was shown to significantly interact with IFNAR1 in a dose-dependent manner. Like IFNβ, MSPEP27 could efficiently bind to IFNAR1 and form a stable peptide-receptor complex during 30ns MD simulations. In vivo analyses revealed that MSPEP27 could lessen inflammation by modulating the levels of inflammatory mediators. According to our results, MSPEP27 peptide could efficiently bind to IFNAR1 and suppress neuroinflammation in vivo. We conclude that MSPEP27 has protective effects against MOG-induced EAE via reduction of immune dysfunction and inflammation.

Therapeutic effects of walnut oil on the animal model of multiple sclerosis

OBJECTIVES

Therapeutic approaches for multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS), are accompanied by various undesirable side effects. Owing to the anti-inflammatory and antioxidant effects of walnut, we investigated its effects on the experimental autoimmune encephalomyelitis (EAE) mouse model of MS.

METHODS

After EAE induction in mice, the treated group was gavaged daily with walnut oil. The weights and clinical symptoms were monitored daily for 21 days following the onset of symptoms. The spleens and brains of the mouse were removed and used for ELISA and histological studies.

RESULTS

The average disease severity and plaque formation in the brains of the walnut oil-treated group were significantly lower (P < 0.05) than those of the untreated group. Stimulated splenocytes of the treated group expressed significantly less INF-γ and interleukin (IL)-17 than the untreated group with no significant differences in IL-10 or IL-5 production. In serum from the treated group, IL-17 expression was also significantly less than in the untreated group, while IL-10 was greater (P < 0.05).

CONCLUSION

Walnut oil significantly reduced disease severity, inhibited plaque formation, and altered cytokine production. More studies are required to identify the mechanism of action of walnut oil as a valuable supplement in the treatment of MS.

Silencing of the RNA-binding protein HuR attenuates hyperalgesia and motor disability in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system associated with progressive neuronal loss and axonal degeneration. Neuronal lesions and dysfunction lead often to neuropathic pain, the most prevalent and difficult to treat pain syndrome observed in MS patients. Despite its widespread occurrence, the underlying neural mechanisms for MS pain are not fully understood. For a better clarification of the pathophysiology of MS-associated pain, we investigated the role of HuR, an RNA-binding protein that positively regulates the stability of many target mRNAs, including several cytokines. The influence of HuR in the generation of the hypernociceptive response in a mouse model of relapsing-remitting experimental autoimmune encephalomyelitis (RR-EAE), an experimental model of MS, was investigated. HuR silencing, obtained through the repeated intrathecal administration of an antisense oligonucleotide (aODN) anti-HuR, completely attenuated hindpaw mechanical allodynia and thermal hyperalgesia developed by RR-EAE mice. Anti-HuR aODN also reduced severity of motor deficits as reflected by a reduction of clinical EAE score and improvement of rotarod performance. RR-EAE mice showed demyelination in spinal cord sections that was significantly reduced by HuR silencing. Double-staining immunofluorescence studies showed a neuronal localization of HuR within dorsal horn spinal cord, consistent with a neuronal mechanism of action. Our findings suggest the involvement of HuR in the hypernociceptive behaviour of RR-EAE mice providing the first pharmacological assessment of an antiallodynic and antihyperalgesic effect of HuR silencing. These data may provide support for HuR modulation as a therapeutic perspective for the management of MS-related neuropathic pain.

Effect of catalpol on remyelination through experimental autoimmune encephalomyelitis acting to promote Olig1 and Olig2 expressions in mice

BACKGROUND

Multiple sclerosis (MS) as an autoimmune disorder is a common disease occurring in central nervous system (CNS) and the remyelination plays a pivotal role in the alleviating neurological impairment in the MS. Catalpol, an effective component extracted from the Chinese herb Radix Rehmanniae, which has been proved protective in cerebral diseases.

METHODS

To determine the protective effects and mechanisms of Catalpol on MS, the mice with experimental autoimmune encephalomyelitis (EAE) were induced by myelin oligodendrocyte glycoprotein (MOG) 35-55, as a model for human MS. Th17 cells were counted by flow cytometric (FCM). The expressions of nerve-glial antigen (NG) 2 and myelin basic protein (MBP) were measured by immunohistochemical staining. Olig1+ and Olig2+/BrdU+ cells were counted by immunofluorescence. Olig1 and Olig2 gene expressions were detected by real-time fluorescent quantitative reverse transcription (qRT) -PCR.

RESULTS

The results showed that Catalpol improved neurological function, reduced inflammatory cell infiltration and demyelination. It could decrease Th17 cells in the peripheral blood. It increased the protein expressions of NG2 and MBP in mice brains, up-regulated markedly protein and gene expressions of Olig1 and Olig2 in terms of timing, site and targets.

CONCLUSIONS

These data demonstrated that Catalpol had a strong neuroprotective effect on EAE mice. Catalpol also plays a role in remyelination by promoting the expressions of Olig1 and Olig2 transcription factors.

Development and Pre-Clinical Evaluation of Recombinant Human Myelin Basic Protein Nano Therapeutic Vaccine in Experimental Autoimmune Encephalomyelitis Mice Animal Model

Recombinant human myelin basic protein (rhMBP) was previously produced in the milk of transgenic cows. Differences in molecular recognition of either hMBP or rhMBP by surface-immobilized anti-hMBP antibodies were demonstrated. This indicated differences in immunological response between rhMBP and hMBP. Here, the activity of free and controlled release rhMBP poly(ε-caprolactone) nanoparticles (NPs), as a therapeutic vaccine against multiple sclerosis (MS) was demonstrated in experimental autoimmune encephalomyelitis (EAE) animal model. Following optimization of nanoformulation, discrete spherical, rough-surfaced rhMBP NPs with high entrapment efficiency and controlled release pattern were obtained. Results indicated that rhMBP was loaded into and electrostatically adsorbed onto the surface of NPs. Subcutaneous administration of free or rhMBP NPs before EAE-induction reduced the average behavioral score in EAE mice and showed only mild histological alterations and preservation of myelin sheath, with rhMBP NPs showing increased protection. Moreover, analysis of inflammatory cytokines (IFN-γ and IL-10) in mice brains revealed that pretreatment with free or rhMBP NPs significantly protected against induced inflammation.

IN CONCLUSION

i) rhMBP ameliorated EAE symptoms in EAE animal model, ii) nanoformulation significantly enhanced efficacy of rhMBP as a therapeutic vaccine and iii) clinical investigations are required to demonstrate the activity of rhMBP NPs as a therapeutic vaccine for MS.

Effect of Bushen Yisui Capsule () on oligodendrocyte lineage genes 1 and 2 in mice with experimental autoimmune encephalomyelitis

OBJECTIVE

To study the effects of Bushen Yisui Capsule (, BSYSC) on the oligodendrocyte lineage genes (Olig) 1 and Olig2 in C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE) in order to explore the remyelination effect of BSYSC.

METHODS

The mice were randomly divided into normal control (NC), EAE model (EAE-M), prednisone acetate (PA, 6 mg/kg), BSYSC high-dose (3.02 g/kg) and BSYSC low-dose (1.51 g/kg) groups. The mice were induced by immunization with myelin oligodendrocyte glycoprotein (MOG) 35-55. The neurological function scores were assessed once daily. The pathological changes in mice brains were observed with hematoxylin-eosin (HE) staining and transmission electron microscope (TEM). The protein expressions of myelin basic protein (MBP), Olig1 and Olig2 in brains were measured by immunohistochemistry. The mRNA expressions of Olig1 and Olig 2 was also determined by quantitative real-time polymerase chain reaction.

RESULTS

Compared with the EAE-M mice, (1) the neurological function scores were significantly decreased in BSYSC-treated mice on days 22 to 40 (P<0.01); (2) the inflammatory cells and demyelination in brains were reduced in BSYSC-treated EAE mice; (3) the protein expression of MBP was markedly increased in BSYSC-treated groups on day 18 and 40 respectively (P<0.05 or P<0.01); (4) the protein expression of Olig1 was increased in BSYSC (3.02 g/kg)-treated EAE mice on day 40 (P<0.01). Protein and mRNA expression of Olig2 was increased in BSYSC-treated EAE mice on day 18 and 40 (P<0.01).

CONCLUSION

The effects of BSYSC on reducing demyelination and promoting remyelination might be associated with the increase of Olig1 and Olig2.

Astragaloside IV inhibits microglia activation via glucocorticoid receptor mediated signaling pathway

Inhibition of microglia activation may provide therapeutic treatment for many neurodegenerative diseases. Astragaloside IV (ASI) with anti-inflammatory properties has been tested as a therapeutic drug in clinical trials of China. However, the mechanism of ASI inhibiting neuroinflammation is unknown. In this study, we showed that ASI inhibited microglia activation both in vivo and in vitro. It could enhance glucocorticoid receptor (GR)-luciferase activity and facilitate GR nuclear translocation in microglial cells. Molecular docking and TR-FRET GR competitive binding experiments demonstrated that ASI could bind to GR in spite of relative low affinity. Meanwhile, ASI modulated GR-mediated signaling pathway, including dephosphorylation of PI3K, Akt, I κB and NF κB, therefore, decreased downstream production of proinflammatory mediators. Suppression of microglial BV-2 activation by ASI was abrogated by GR inhibitor, RU486 or GR siRNA. Similarly, RU486 counteracted the alleviative effect of ASI on microgliosis and neuronal injury in vivo. Our findings demonstrated that ASI inhibited microglia activation at least partially by activating the glucocorticoid pathway, suggesting its possible therapeutic potential for neuroinflammation in neurological diseases.

Hydroxycitric acid ameliorates inflammation and oxidative stress in mouse models of multiple sclerosis

Hydroxycitric acid (HCA) is derived primarily from the Garcinia plant and is widely used for its anti-inflammatory effects. Multiple sclerosis can cause an inflammatory demyelination and axonal damage. In this study, to validate the hypothesis that HCA exhibits therapeutic effects on multiple sclerosis, we established female C57BL/6 mouse models of multiple sclerosis, i.e., experimental autoimmune encephalomyelitis, using Complete Freund's Adjuvant (CFA) emulsion containing myelin oligodendrocyte glycoprotein (35-55). Treatment with HCA at 2 g/kg/d for 3 weeks obviously improved the symptoms of nerve injury of experimental autoimmune encephalomyelitis mice, decreased serum interleulin-6, tumor necrosis factor alpha, nitric oxide, and malondialdehyde levels, and increased superoxide dismutase and glutathione reductase activities. These findings suggest that HCA exhibits neuroprotective effects on multiple sclerosis-caused nerve injury through ameliorating inflammation and oxidative stress.

Antiallodynic effects of alpha lipoic acid in an optimized RR-EAE mouse model of MS-neuropathic pain are accompanied by attenuation of upregulated BDNF-TrkB-ERK signaling in the dorsal horn of the spinal cord

Neuropathic pain may affect patients with multiple sclerosis (MS) even in early disease. In an experimental autoimmune encephalomyelitis (EAE)-mouse model of MS, chronic alpha lipoic acid (ALA) treatment reduced clinical disease severity, but MS-neuropathic pain was not assessed. Hence, we investigated the pain-relieving efficacy and mode of action of ALA using our optimized relapsing-remitting (RR)-EAE mouse model of MS-associated neuropathic pain. C57BL/6 mice were immunized with MOG35-55 and adjuvants (Quil A and pertussis toxin) to induce RR-EAE; sham-mice received adjuvants only. RR-EAE mice received subcutaneous ALA (3 or 10 mg kg(-1) day(-1)) or vehicle for 21 days (15-35 d.p.i.; [days postimmunization]); sham-mice received vehicle. Hindpaw hypersensitivity was assessed blinded using von Frey filaments. Following euthanasia (day 35 d.p.i.), lumbar spinal cords were removed for immunohistochemical and molecular biological assessments. Fully developed mechanical allodynia in the bilateral hindpaws of vehicle-treated RR-EAE mice was accompanied by marked CD3(+) T-cell infiltration, microglia activation, and increased brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) signaling in the dorsal horn of the lumbar spinal cord. Consequently, phospho-ERK, a marker of central sensitization in neuropathic pain, was upregulated in the spinal dorsal horn. Importantly, hindpaw hypersensitivity was completely attenuated in RR-EAE mice administered ALA at 10 mg kg(-1) day(-1) but not 3 mg kg(-1) day(-1). The antiallodynic effect of ALA (10 mg kg(-1) day(-1)) was associated with a marked reduction in the aforementioned spinal dorsal horn markers to match their respective levels in the vehicle-treated sham-mice. Our findings suggest that ALA at 10 mg kg(-1) day(-1) produced its antiallodynic effects in RR-EAE mice by reducing augmented CD3(+) T-cell infiltration and BDNF-TrkB-ERK signaling in the spinal dorsal horn.

Effects of Bu Shen Yi Sui Capsule on Th17/Treg cytokines in C57BL/6 mice with experimental autoimmune encephalomyelitis

Background

T helper (Th) 17 and regulatory T (Treg) cells play a critical role in the pathogenesis of multiple sclerosis (MS) disease. Bu Shen Yi Sui Capsule (BSYSC), a traditional Chinese medicine formula, has been used clinically for the treatment of MS patients in China.

Methods

To evaluate the neuroprotective effects and the underlying mechanisms of BSYSC on MS, experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice was induced with myelin oligodendrocyte glycoprotein (MOG) _35–55. Th17 and Treg cells and the related cytokines were detected by flow cytometry, ELISA, real-time quantitative reverse transcription PCR, western blot and immunohistochemistry.

Results

We found that BSYSC improved neurological function, reduced inflammatory cell infiltration and damage to the axons and myelin in the brain and spinal cord. BSYSC down-regulated markedly the ratio of CD4 + IL-17+/CD4 + CD25 + FoxP3+ T cells in the spleen, decreased the cytokines of IL-17A, IL-6, IL-23, TGF-beta1 in the brain, and dropped the ratio of IL-17A and FoxP3 mRNA and protein in the brain or spinal cord at different stages.

Conclusions

The study demonstrated that BSYSC had a strong neuroprotective effect on EAE mice. The protective mechanisms of BSYSC might be associated with mediating the regulation of Th17/Treg cells.

Prophylactic Effect of BIO-1211 Small-Molecule Antagonist of VLA-4 in the EAE Mouse Model of Multiple Sclerosis

BACKGROUND AND PURPOSE

Some functional limitations and economic burden of therapeutic antibodies indicated that introducing of alternative therapeutic compounds with same or different mechanism of action could be worthwhile. In this regard small-molecule antagonists can have a wide range of impacts, so in this research, we examine the prophylactic effects of BIO-1211 [Very Late Antigen-4 (VLA4) blocker], in experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis in comparison with commercial available medicine, Natalizumab (NTZ)].

METHODS

EAE was induced by subcutaneous immunization of myelin oligodendrocyte glycoprotein (MOG35-55) in 8-week-old C57BL/6 mice. During EAE induction, mice were separated to distinct groups and provided either BIO-1211 (5 and 10 mg/kg) or NTZ (5 mg/kg) and co-administration of these two compounds. After 21 days, neuro-inflammatory responses were analyzed using qRT-PCR, western blot, and ELISA methods. Pervade of immune cells to brain was examined by Evans blue staining and immunohistochemistry (IHC) analysis of specific markers of microglia/monocytes (CD11b) and leukocytes (CD45).

RESULTS

Targeted disruption of VLA4/VCAM1 interactions, by BIO-1211 agonist in mice, results in reduced cytokines expression, leukocyte trafficking, and inhibition of inflammatory responses in EAE (p < 0.01) in a dose-independent manner (data not shown). Mice treated with both BIO-1211 and NTZ exhibited a considerable depletion in the EAE clinical score, which correlated with decreased expression of TNF-α, IL-17, IFN-γ and pervade of CD11b(+) and CD45(+) cells into the cerebral cortex.

CONCLUSION

Our results indicated that BIO12-11 compound would be an useful tool to further understand the biological roles of VLA4/VCAM1 interactions, and could also be considered as EAE-suppressing agent.

Establishment and characterization of an optimized mouse model of multiple sclerosis-induced neuropathic pain using behavioral, pharmacologic, histologic and immunohistochemical methods

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that causes debilitating central neuropathic pain in many patients. Although mouse models of experimental autoimmune encephalomyelitis (EAE) have provided insight on the pathobiology of MS-induced neuropathic pain, concurrent severe motor impairments confound quantitative assessment of pain behaviors over the disease course. To address this issue, we have established and characterized an optimized EAE-mouse model of MS-induced neuropathic pain. Briefly, C57BL/6 mice were immunized with MOG35-55 (200μg) and adjuvants comprising Quil A (45μg) and pertussis toxin (2×250ng). The traditionally used Freund's Complete Adjuvant (FCA) was replaced with Quil A, as FCA itself induces CNS neuroinflammation. Herein, EAE-mice exhibited a mild relapsing-remitting clinical disease course with temporal development of mechanical allodynia in the bilateral hindpaws. Mechanical allodynia was fully developed by 28-30days post-immunization (p.i.) and was maintained until study completion (52-60days p.i.), in the absence of confounding motor deficits. Single bolus doses of amitriptyline (1-7mg/kg), gabapentin (10-50mg/kg) and morphine (0.1-2mg/kg) evoked dose-dependent analgesia in the bilateral hindpaws of EAE-mice; the corresponding ED50s were 1.5, 20 and 1mg/kg respectively. At day 39 p.i. in EAE-mice exhibiting mechanical allodynia in the hindpaws, there was marked demyelination and gliosis in the brain and lumbar spinal cord, mirroring these pathobiologic hallmark features of MS in humans. Our optimized EAE-mouse model of MS-associated neuropathic pain will be invaluable for future investigation of the pathobiology of MS-induced neuropathic pain and for efficacy profiling of novel molecules as potential new analgesics for improved relief of this condition.

Astragalosides from Radix Astragali benefits experimental autoimmune encephalomyelitis in C57BL /6 mice at multiple levels

Background

Radix Astragali is famous for its beneficial effect on inflammation associated diseases. This study was to assess the efficacy of astragalosides (AST) extracted from Radix Astragali, on the progression of experimental autoimmune encephalomyelitis (EAE), and explore its possible underlying molecular mechanisms.

Methods

EAE was induced by subcutaneous immunization of MOG_35–55. Infiltration of inflammatory cells was examined by HE staining. ROS level was detected by measuring infiltrated hydroethidine. Leakage of blood brain barrier (BBB) was assessed using Evan’s blue dye extravasation method. Levels of inflammatory cytokines were measured using ELISA kits. Activities of total-SOD, GSH-Px, and iNOS and MDA concentration were measured using biochemical analytic kits. Gene expression was detected using real-time PCR method. Protein expression was assayed using western blotting approach.

Results

AST administration attenuated the progression of EAE in mice remarkably. Further studies manifested that AST treatment inhibited infiltration of inflammatory cells, lessened ROS production and decreased BBB leakage. In peripheral immune-systems, AST up-regulated mRNA expression of transcriptional factors T-bet and Foxp3 but decreased that of RORγt to modulate T cell differentiation. In CNS, AST stopped BBB leakage, reduced ROS production by up-regulation of T-SOD, and reduced neuroinflammation by inhibition of iNOS and other inflammatory cytokines. Moreover, AST inhibited production of p53 and phosphorylation of tau by modulation of the Bcl-2/Bax ratio.

Conclusions

AST orchestrated multiple pathways, including immuno-regulation, anti-oxidative stress, anti-neuroinflammation and anti-neuroapoptosis involved in the MS pathogenesis, to prevent the deterioration of EAE, which paves the way for the application of it in clinical prevention/therapy of MS.

Calcium intervention ameliorates experimental model of multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) is the most common inflammatory disease of the CNS. Experimental autoimmune encephalomyelitis (EAE) is a widely used model for MS. In the present research, our aim was to test the therapeutic efficacy of Calcium (Ca) in an experimental model of MS.

METHODS

In this study the experiment was done on C57BL/6 mice. EAE was induced using 200 μg of the MOG35-55 peptide emulsified in CFA and injected subcutaneously on day 0 over two flank areas. In addition, 250 ng of pertussis toxin was injected on days 0 and 2. In the treatment group, 30 mg/kg Ca was administered intraperitoneally four times at regular 48 hour intervals. The mice were sacrificed 21 days after EAE induction and blood samples were taken from their hearts. The brains of mice were removed for histological analysis and their isolated splenocytes were cultured.

RESULTS

Our results showed that treatment with Ca caused a significant reduction in the severity of the EAE. Histological analysis indicated that there was no plaque in brain sections of Ca treated group of mice whereas 4 ± 1 plaques were detected in brain sections of controls. The density of mononuclear infiltration in the CNS of Ca treated mice was lower than in controls. The serum level of Nitric Oxide in the treatment group was lower than in the control group but was not significant. Moreover, the levels of IFN-γ in cell culture supernatant of splenocytes in treated mice were significantly lower than in the control group.

CONCLUSION

The data indicates that Ca intervention can effectively attenuate EAE progression.

Protective effects of pioglitazone against immunoglobulin deposition on heart of streptozotocin-induced diabetic rats

AIM

Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists have immunomodulatory and anti-inflammatory effects. The study investigated the autoimmune injuries of diabetic cardiomyopathy (DCM) and tested the hypothesis that PPAR-γ agonists suppress disordered immune responses in diabetic heart, thereby preventing evolution of DCM.

METHODS

STZ-induced diabetic rats were assigned to five groups: DM group, given no treatment; INS group, given insulin (4 U kg(-1) d(-1)); PIL group, given low dose pioglitazone (4 mg kg(-1) d(-1)); PIL/INS group, given both low dose pioglitazone and insulin; PIH group, given high dose pioglitazone (20 mg kg(-1) d(-1)). Normal rats (CON group) were also monitored as control. The pathologic abnormalities of hearts were observed. The immunoglobulin deposition was examined by immunohistochemistry and immunofluorescence.

RESULTS

At 16 weeks, interstitial fibrosis was shown in diabetic heart which was accompanied by plenty of inflammatory cells infiltrated. Pioglitazone therapy could ameliorate the cardiac injuries. Shown by immunohistochemistry, the difference of integrated optical density (IOD) of immunoglobulin deposition among each group had statistic significance. No obvious immunoglobulins were deposited in the intercellular substance of heart in CON group (IgA 290.8 ± 88.1, IgG 960.4 ± 316.0 and IgM 341.3 ± 67.9). But the deposition of immunoglobulins increased significantly in DM group (IgA 7,047.5 ± 1,328.3, P < 0.05; IgG 28,945.9 ± 5,160.7, P < 0.05 and IgM 8,580.8 ± 1,336.8, P < 0.05). Administration of pioglitazone greatly reduced the increased deposition in a dose-dependent fashion. Moreover, the statistical significance was the same with immunofluorescence analysis as with immunohistochemical examination.

CONCLUSIONS

The data suggest that disordered immune responses play an important role in the pathogenesis of DCM. Pioglitazone showed protective effects by inhibiting the immunoglobulin deposition on diabetic myocardium.

Multiple sclerosis-induced neuropathic pain: pharmacological management and pathophysiological insights from rodent EAE models

In patients with multiple sclerosis (MS), pain is a frequent and disabling symptom. The prevalence is in the range 29-86 % depending upon the assessment protocols utilised and the definition of pain applied. Neuropathic pain that develops secondary to demyelination, neuroinflammation and axonal damage in the central nervous system is the most distressing and difficult type of pain to treat. Although dysaesthetic extremity pain, L'hermitte's sign and trigeminal neuralgia are the most common neuropathic pain conditions reported by patients with MS, research directed at gaining insight into the complex mechanisms underpinning the pathobiology of MS-associated neuropathic pain is in its relative infancy. By contrast, there is a wealth of knowledge on the neurobiology of neuropathic pain induced by peripheral nerve injury. To date, the majority of research in the MS field has used rodent models of experimental autoimmune encephalomyelitis (EAE) as these models have many clinical and neuropathological features in common with those observed in patients with MS. However, it is only relatively recently that EAE-rodents have been utilised to investigate the mechanisms contributing to the development and maintenance of MS-associated central neuropathic pain. Importantly, EAE-rodent models exhibit pro-nociceptive behaviours predominantly in the lower extremities (tail and hindlimbs) as seen clinically in patients with MS-neuropathic pain. Herein, we review research to date on the pathophysiological mechanisms underpinning MS-associated neuropathic pain as well as the pharmacological management of this condition. We also identify knowledge gaps to guide future research in this important field.

Astragaloside IV attenuates experimental autoimmune encephalomyelitis of mice by counteracting oxidative stress at multiple levels

Multiple sclerosis (MS) is a chronic autoimmune neuroinflammatory disease found mostly in young adults in the western world. Oxidative stress induced neuronal apoptosis plays an important role in the pathogenesis of MS. In current study, astragaloside IV (ASI), a natural saponin molecule isolated from Astragalus membranceus, given at 20 mg/kg daily attenuated the severity of experimental autoimmune encephalomyelitis (EAE) in mice significantly. Further studies disclosed that ASI treatment inhibited the increase of ROS and pro-inflammatory cytokine levels, down-regulation of SOD and GSH-Px activities, and elevation of iNOS, p53 and phosphorylated tau in central nervous system (CNS) as well as the leakage of BBB of EAE mice. Meanwhile, the decreased ratio of Bcl-2/Bax was reversed by ASI. Moreover, ASI regulated T-cell differentiation and infiltration into CNS. In neuroblast SH-SY5Y cells, ASI dose-dependently reduced cellular ROS level and phosphorylation of tau in response to hydrogen peroxide challenge by modulation of Bcl-2/Bax ratio. ASI also inhibited activation of microglia both in vivo and in vitro. iNOS up-regulation induced by IFNγ stimulation was abolished by ASI dose-dependently in BV-2 cells. In summary, ASI prevented the severity of EAE progression possibly by counterbalancing oxidative stress and its effects via reduction of cellular ROS level, enhancement of antioxidant defense system, increase of anti-apoptotic and anti-inflammatory pathways, as well as modulation of T-cell differentiation and infiltration into CNS. The study suggested ASI may be effective for clinical therapy/prevention of MS.

Modeling the heterogeneity of multiple sclerosis in animals

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system (CNS) manifested with varying clinical course, pathology, and inflammatory patterns. There are multiple animal models that reflect different aspects of this heterogeneity. Collectively, these models reveal a balance between pathogenic and regulatory CD4(+) T cells, CD8(+) T cells, and B cells that influences the incidence, timing, and severity of CNS autoimmunity. In this review we discuss experimental autoimmune encephalomyelitis (EAE) models that have been used to study the pathogenic and regulatory roles of these immune cells; models that recapitulate different aspects of the disease seen in patients with MS, and questions remaining for future studies.

Mechanism of Erhuang capsule for treatment of multiple sclerosis

Erhuang capsule, a typical formula based on traditional Chinese medicine theory, is widely used to ameliorate multiple sclerosis, inflammation and side effects of glucocorticoid treatment. Oligodendrocyte precursor cells are neural stem cells that are important for myelin repair and regeneration. In the present study, Erhuang capsule effectively improved clinical symptoms and neurological function scores, reduced mortality and promoted recovery of neurological functions of mice with experimental autoimmune encephalomyelitis. The mechanism of action involved significant increases in oligodendrocyte precursor cell proliferation in specific regions of the brain and spinal cord, increased oligodendrocyte lineage gene 2 expression and enhanced oligodendrocyte precursor cell differentiation.

Dibutyryl cyclic AMP inhibits the progression of experimental autoimmune encephalomyelitis and potentiates recruitment of endogenous neural stem cells

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system. Cyclic AMP and its analogs enhance regeneration of adult mammalian central nervous system (CNS). Endogenous neural stem cells (NSCs) play a pivotal role in CNS regeneration, producing new neuron and glial cells. Here, we examined the effect of dibutyryl cyclic AMP (dbcAMP) on experimental autoimmune encephalomyelitis (EAE) symptoms, endogenous remyelination, and recruitment of NSCs. EAE was induced by immunizing mice using myelin oligodendrocyte glycoprotein peptide and pertussis toxin. Proliferative cells within CNS were labeled using repetitive systemic injections of 5-bromo-2-deoxyuridine (BrdU) before EAE induction. Myelin staining was performed using Luxol fast blue. The number of nestin(+) and BrdU(+) cells in subventricular zone (SVZ) and olfactory bulb (OB) was evaluated using immunohistochemistry. dbcAMP suppressed EAE progression and decreased the extent of demyelinated plaques in the lumbar spinal cord. EAE induction reduced the number of proliferative cells in SVZ and increased their population in OB. EAE also increased the number of nestin(+) cells in OB. We also found that dbcAMP increased the recruitment of NSCs into the OB and brain parenchyma of EAE mice. Our results suggest dbcAMP as a potential therapy for inducing myelin repair in the context of demyelinating diseases like multiple sclerosis. Its positive effect seems to be mediated, at least partially, by endogenous neural stem cells and their increased recruitment.

The PPAR-γ agonist pioglitazone protects cortical neurons from inflammatory mediators via improvement in peroxisomal function

Background

Inflammation is known to play a pivotal role in mediating neuronal damage and axonal injury in a variety of neurodegenerative disorders. Among the range of inflammatory mediators, nitric oxide and hydrogen peroxide are potent neurotoxic agents. Recent evidence has suggested that oligodendrocyte peroxisomes may play an important role in protecting neurons from inflammatory damage.

Methods

To assess the influence of peroxisomal activation on nitric oxide mediated neurotoxicity, we investigated the effects of the peroxisomal proliferator activated receptor (PPAR) gamma agonist, pioglitazone in primary cortical neurons that were either exposed to a nitric oxide donor or co-cultured with activated microglia.

Results

Pioglitazone protected neurons and axons against both nitric-oxide donor-induced and microglia-derived nitric oxide-induced toxicity. Moreover, cortical neurons treated with this compound showed a significant increase in the protein and gene expression of PPAR-gamma, which was associated with a concomitant increase in the enzymatic activity of catalase. In addition, the protection of neurons and axons against hydrogen peroxide-induced toxicity afforded by pioglitazone appeared to be dependent on catalase.

Conclusions

Collectively, these observations provide evidence that modulation of PPAR-gamma activity and peroxisomal function by pioglitazone attenuates both NO and hydrogen peroxide-mediated neuronal and axonal damage suggesting a new therapeutic approach to protect against neurodegenerative changes associated with neuroinflammation.

Indole-propionic acid derivatives as potent, S1P3-sparing and EAE efficacious sphingosine-1-phosphate 1 (S1P1) receptor agonists

Novel indole-propionic acid derivatives were developed as sphingosine-1-phosphate (S1P) receptor agonists through a systematic SAR study. The optimized and S1P(3) selective S1P(1) agonist 9f induced peripheral blood lymphocyte reduction in vivo and has an excellent efficacy in mouse experimental autoimmune encephalomyelitis (EAE).

The PPAR-γ agonist pioglitazone modulates inflammation and induces neuroprotection in parkinsonian monkeys

BACKGROUND

Activation of the peroxisome proliferator-activated receptor gamma (PPAR-γ) has been proposed as a possible neuroprotective strategy to slow down the progression of early Parkinson's disease (PD). Here we report preclinical data on the use of the PPAR-γ agonist pioglitazone (Actos®; Takeda Pharmaceuticals Ltd.) in a paradigm resembling early PD in nonhuman primates.

METHODS

Rhesus monkeys that were trained to perform a battery of behavioral tests received a single intracarotid arterial injection of 20 ml of saline containing 3 mg of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Twenty-four hours later the monkeys were assessed using a clinical rating scale, matched accordingly to disability, randomly assigned to one of three groups [placebo (n = 5), 2.5 (n = 6) or 5 (n = 5) mg/kg of pioglitazone] and their treatments started. Three months after daily oral dosing, the animals were necropsied.

RESULTS

We observed significant improvements in clinical rating score (P = 0.02) in the animals treated with 5 mg/kg compared to placebo. Behavioral recovery was associated with preservation of nigrostriatal dopaminergic markers, observed as higher tyrosine hydroxylase (TH) putaminal optical density (P = 0.011), higher stereological cell counts of TH-ir (P = 0.02) and vesicular monoamine transporter-2 (VMAT-2)-ir nigral neurons (P = 0.006). Stereological cell counts of Nissl stained nigral neurons confirmed neuroprotection (P = 0.017). Pioglitazone-treated monkeys also showed a dose-dependent modulation of CD68-ir inflammatory cells, that was significantly decreased for 5 mg/kg treated animals compared to placebo (P = 0.018). A separate experiment to assess CSF penetration of pioglitazone revealed that 5 mg/kg p.o. induced consistently higher levels than 2.5 mg/kg and 7.5 mg/kg. p.o.

CONCLUSIONS

Our results indicate that oral administration of pioglitazone is neuroprotective when administered early after inducing a parkinsonian syndrome in rhesus monkeys and supports the concept that PPAR-γ is a viable target against neurodegeneration.

Regulation of Glial Cell Functions by PPAR-gamma Natural and Synthetic Agonists

In the recent years, the peroxisome proliferator-activated receptor-γ (PPAR-γ), a well known target for type II diabetes treatment, has received an increasing attention for its therapeutic potential in inflammatory and degenerative brain disorders. PPAR-γ agonists, which include naturally occurring compounds (such as long chain fatty acids and the cyclopentenone prostaglandin 15-deoxy Δ^12,14 prostaglandin J₂), and synthetic agonists (among which the thiazolidinediones and few nonsteroidal anti-inflammatory drugs) have shown anti-inflammatory and protective effects in several experimental models of Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, multiple sclerosis and stroke, as well as in few clinical studies. The pleiotropic effects of PPAR-γ agonists are likely to be mediated by several mechanisms involving anti-inflammatory activities on peripheral immune cells (macrophages and lymphocytes), as well as direct effects on neural cells including cerebral vascular endothelial cells, neurons, and glia. In the present article, we will review the recent findings supporting a major role for PPAR-γ agonists in controlling neuroinflammation and neurodegeneration through their activities on glial cells, with a particular emphasis on microglial cells as major macrophage population of the brain parenchyma and main actors in brain inflammation.

PPAR-gamma, Microglial Cells, and Ocular Inflammation: New Venues for Potential Therapeutic Approaches

The last decade has witnessed an increasing interest for the role played by the peroxisome proliferator-activated receptor-γ (PPAR-γ) in controlling inflammation in peripheral organs as well as in the brain. Activation of PPAR-γ has been shown to control the response of microglial cells, the main macrophage population found in brain parenchyma, and limit the inflammation. The anti-inflammatory capacity of PPAR-γ agonists has led to the hypothesis that PPAR-γ might be targeted to modulate degenerative brain diseases in which inflammation has been increasingly recognized as a significant component. Recent experimental evidence suggests that PPAR-γ agonists could be exploited to treat ocular diseases such as diabetic retinopathy, age-related macular degeneration, autoimmune uveitis, and optic neuritis where inflammation has relevant role. Additional PPAR-γ agonist beneficial effects could involve amelioration of retinal microcirculation and inhibition of neovascularization. However, PPAR-γ activation could, in some instances, aggravate the ocular pathology, for example, by increasing the synthesis of vascular endothelial growth factor, a proangiogenic factor that could trigger a vicious circle and further deteriorate retinal perfusion. The development of new in vivo and in vitro models to study ocular inflammation and how to modulate for the eye benefit will be instrumental for the search of effective therapies.

Peroxisome proliferator-activated receptor-γ agonists prevent in vivo remodeling of human artery induced by alloreactive T cells

BACKGROUND

Ligands activating the transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) have antiinflammatory effects. Vascular rejection induced by allogeneic T cells can be responsible for acute and chronic graft loss. Studies in rodents suggest that PPARγ agonists may inhibit graft vascular rejection, but human T-cell responses to allogeneic vascular cells differ from those in rodents, and the effects of PPARγ in human transplantation are unknown.

METHODS AND RESULTS

We tested the effects of PPARγ agonists on human vascular graft rejection using a model in which human artery is interposed into the abdominal aorta of immunodeficient mice, followed by adoptive transfer of allogeneic (to the artery donor) human peripheral blood mononuclear cells. Interferon-γ-dependent rejection ensues within 4 weeks, characterized by intimal thickening, T-cell infiltrates, and vascular cell activation, a response resembling clinical intimal arteritis. The PPARγ agonists 15-deoxy-prostaglandin-J(2), ciglitazone, and pioglitazone reduced intimal expansion, intimal infiltration of CD45RO(+) memory T cells, and plasma levels of inflammatory cytokines. The PPARγ antagonist GW9662 reversed the protective effects of PPARγ agonists, confirming the involvement of PPARγ-mediated pathways. In vitro, pioglitazone inhibited both alloantigen-induced proliferation and superantigen-induced transendothelial migration of memory T cells, indicating the potential mechanisms of PPARγ effects.

CONCLUSION

Our results suggest that PPARγ agonists inhibit allogeneic human memory T cell responses and may be useful for the treatment of vascular graft rejection.

Peroxisome proliferator-activated receptor γ ligands regulate neural stem cell proliferation and differentiation in vitro and in vivo

Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a family of ligand-activated nuclear receptors and its ligands are known to control many physiological and pathological situations. Its role in the central nervous system has been under intense analysis during the last years. Here we show a novel function for PPARγ in controlling stem cell expansion in the adult mammalian brain. Adult rats treated with pioglitazone, a specific ligand of PPARγ, had elevated numbers of proliferating progenitor cells in the subventricular zone and the rostral migratory stream. Electron microscopy analysis also showed important changes in the subventricular zone ultrastructure of pioglitazone-treated animals including an increased number of migratory cell chains. These results were further confirmed in vitro. Neurosphere assays revealed significant increases in the number of neurosphere forming cells from pioglitazone- and rosiglitazone (two specific ligands of PPARγ receptor)-treated cultures that exhibited enhanced capacity for cell migration and differentiation. The effects of pioglitazone were blocked by the PPARγ receptor antagonists GW9662 and T0070907, suggesting that its effects are mediated by a mechanism dependent on PPARγ activation. These results indicate for the first time that activation of PPARγ receptor directly regulates proliferation, differentiation, and migration of neural stem cells in vivo.