Oral D-mannose treatment suppresses experimental autoimmune encephalomyelitis via induction of regulatory T cells.

D-mannose (D-m) is a glucose epimer found in natural products, especially fruits. In mouse models of diabetes and airway inflammation, D-m supplementation via drinking water attenuated pathology by modifying cellular energy metabolism, leading to the activation of latent transforming growth factor beta (TGF-ß), which in turn induced T regulatory cells (Tregs). Given that Tregs are important in controlling neuroinflammation in experimental autoimmune encephalomyelitis (EAE) and likely in multiple sclerosis (MS), we hypothesized that D-m could also suppress EAE. We found that D-m delayed disease onset and reduced disease severity in two models of EAE. Importantly, D-m treatment prevented relapses in a relapsing-remitting model of EAE, which mimics the most common clinical manifestation of MS. EAE suppression was accompanied by increased frequency of CD4+FoxP3+ Tregs in the central nervous system, suggesting that EAE suppression resulted from Treg cell induction by D-m. These findings suggest that D-m has the potential to be a safe and low-cost complementary therapy for MS.

Carnosol Modulates Th17 Cell Differentiation and Microglial Switch in Experimental Autoimmune Encephalomyelitis.

Medicinal plants as a rich pool for developing novel small molecule therapeutic medicine have been used for thousands of years. Carnosol as a bioactive diterpene compound originated from Rosmarinus officinalis (Rosemary) and Salvia officinalis, herbs extensively applied in traditional medicine for the treatment of multiple autoimmune diseases (1). In this study, we investigated the therapeutic effects and molecule mechanism of carnosol in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Carnosol treatment significantly alleviated clinical development in the myelin oligodendrocyte glycoprotein (MOG35-55) peptide-induced EAE model, markedly decreased inflammatory cell infiltration into the central nervous system and reduced demyelination. Further, carnosol inhibited Th17 cell differentiation and signal transducer and activator of transcription 3 phosphorylation, and blocked transcription factor NF-κB nuclear translocation. In the passive-EAE model, carnosol treatment also significantly prevented Th17 cell pathogenicity. Moreover, carnosol exerted its therapeutic effects in the chronic stage of EAE, and, remarkably, switched the phenotypes of infiltrated macrophage/microglia. Taken together, our results show that carnosol has enormous potential for development as a therapeutic agent for autoimmune diseases such as MS.

Matrine Treatment Blocks NogoA-Induced Neural Inhibitory Signaling Pathway in Ongoing Experimental Autoimmune Encephalomyelitis.

Myelin-associated inhibitors, such as NogoA, myelin-associated glycoprotein (MAG), and oligodendrocyte myelin glycoprotein (OMgp), play a pivotal role in the lack of neuroregeneration in multiple sclerosis, an inflammatory demyelinating disease of the central nervous system (CNS). Matrine (MAT), a monomer that is used in traditional Chinese medicine as an anti-inflammatory agent, has shown beneficial effects in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, the underlying mechanisms of MAT-induced EAE amelioration are not fully understood. In the present study, we show that MAT treatment suppressed ongoing EAE, and this effect correlated with an increased expression of growth-associated protein 43, an established marker for axonal regeneration. MAT treatment significantly reduced the levels of NogoA, its receptor complex NgR/p75NTR/LINGO-1, and their downstream RhoA/ROCK signaling pathway in the CNS. In contrast, intracellular cyclic AMP (cAMP) levels and its protein kinase (protein kinase A (PKA)), which can promote axonal regrowth by inactivating the RhoA, were upregulated. Importantly, adding MAT in primary astrocytes in vitro largely induced cAMP/PKA expression, and blockade of cAMP significantly diminished MAT-induced expression of PKA and production of BDNF, a potent neurotrophic factor for neuroregeneration. Taken together, our findings demonstrate that the beneficial effects of MAT on EAE can be attributed not only to its capacity for immunomodulation, but also to its directly promoting regeneration of the injured CNS.

Multitarget Therapeutic Effect of Fasudil in APP/PS1transgenic Mice.

INTRODUCTION: Therapeutic strategies targeting Alzheimer's disease-related molecule ß- amyloid (Aß), Tau protein and ß-site amyloid precursor protein cleaving enzyme (BACE) have been recently explored. However, the treatment effect for single target is not ideal. Based on multiaspect roles of Rho kinase inhibitor Fasudil on neuroprotection, neurorepair and immunomodulation, we observed therapeutic potential of Fasudil and explored possible mechanisms in amyloid precursor protein/ presenilin-1 transgenic (APP/PS1 Tg) mice, an animal model of Alzheimer's disease. METHODS: APP/PS1 Tg mice were treated with Fasudil (25 mg/kg/day) for 2 months by intraperitoneal injection. Mouse behavior tests were recorded every day. The expression of Aß deposition, Tau protein phosphorylation, BACE and postsynaptic density 95 (PSD-95) in hippocampus was assayed. The levels in the brain of Toll-like receptors (TLRs)-nuclear factor kappa B/p65（NF-κB/p65)- myeloid differentiation primary response gene 88 (MyD88) inflammatory cytokine axis were measured. RESULTS: Fasudil treatment ameliorated learning and memory deficits, accompanied by reduced Aß deposition, Tau protein phosphorylation, and BACE expression, as well as increased PSD-95 expression in hippocampus. Fasudil intervention also inhibited TLR-2/4, p-NF-κB/p65, MyD88, interleukin-1beta, interleukin-6 and tumor necrosis factor-α for TLRs-NF-κB-MyD88 inflammatory cytokine axis and the induction of interleukin-10. CONCLUSION: Fasudil exhibited multitarget therapeutic effect in APP/PS1 Tg mice. The study provides preclinical evidence that Fasudil treatment ameliorated memory deficits in APP/PS1 Tg mice, accompanied by the reduction of Aß deposition and Tau protein phosphorylation, the decrease of BACE and the increase of PSD-95, as well as inhibition of TLRs-NF-κB-MyD88 inflammatory cytokine axis. However, these results still need to be repeated and confirmed before clinical application.

Identification of UQCRB as an oxymatrine recognizing protein using a T7 phage display screen.

ETHNOPHARMACOLOGICAL RELEVANCE: Sophora flavescens Aiton (Radix Sophorae Flavescentis, Kushen) is used in traditional Chinese medicine to treat chronic hepatitis B (CHB), and has the ability to clear heat and dampness from the body. Oxymatrine is one of the major bioactive compounds extracted from Sophora flavescens Aiton and constitutes more than 90% of the oxymatrine injection commonly used for CHB treatment in clinics in China. AIM OF THE STUDY: We aim to analyze the protein binding target of oxymatrine in treating CHB by screening a T7 phage display cDNA library of human CHB and examine the biochemistry of protein-ligand binding between oxymatrine and its ligands. MATERIALS AND METHODS: A T7 phage cDNA library of human CHB was biopanned by affinity selection using oxymatrine as bait. The interaction of oxymatrine with its candidate binding protein was investigated by affinity assay, molecular docking, Isothermal Titration Calorimetry (ITC) and Surface Plasmon Resonance (SPR). RESULTS: A library of potential oxymatrine binding peptides was generated. Ubiquinol-cytochrome c reductase binding protein (UQCRB) was one of the candidate binding proteins of oxymatrine. UQCRB-displaying T7 phage binding numbers in the oxymatrine group were significantly higher than that in the control group, biotin group, and matrine group (p<0.05 or p<0.01). Three-dimensional structure modeling of the UQCRB with oxymatrine showed that their binding interfaces matched and oxymatrine inserted into a deeper pocket of UQCRB, which mainly involved amino acid residues Tyr21, Arg33, Tyr83, Glu84, Asp86, Pro88, and Glu91. The binding affinity constant (Kb) from SPR was 4.2mM. The Kb from ITC experiment was 3.9mM and stoichiometry was fixed as 1, which fit very well with the result of SPR. The binding of oxymatrine to UQCRB was driven by strong enthalpy forces such as hydrogen bonds and polar interactions as the heat released was about 157kcal/mol and ΔG was less than zero. CONCLUSIONS: In this study, using the T7 phage display system, we have identified UQCRB as a direct binding protein of oxymatrine. Furthermore, the specificity and molecular interaction of oxymatrine with UQCRB were also determined. The binding of UQCRB to oxymatrine suggests that UQCRB is a potential target of oxymatrine in treating CHB. These results provide new understanding into the mechanism of oxymatrine and insights into the strategy on the treatment of CHB.

The Pharmacological Effects and Mechanism of Tripterygium wilfordii Hook F in Central Nervous System Autoimmunity.

OBJECTIVE: Extracts of the Chinese herb Tripterygium wilfordii Hook F (TwHF) have potent anti-inflammatory functions and are widely used to treat rheumatoid arthritis and Crohn's disease. They have also been considered as potential drugs in the treatment of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis. METHODS: A systematic search of MEDLINE, EMBASE, PubMed, and the China National Knowledge Infrastructure (CNKI) was performed. We reviewed many Chinese- and English-language articles. RESULTS: Recent studies have indicated that TwHF extracts, such as triptolide and tripchlorolide, are able to attenuate progression of this neuroimmunologic disorder because of their immunoregulatory, neurotrophic, and neuroprotective effects, but use of these extracts is often accompanied by acute and chronic toxicity. CONCLUSIONS: This review systematically summarizes the effects, safety consideration, and molecular mechanisms of action of TwHF extracts with regard to their inhibition of microglia activation, T cell functions, and transcriptional activation of nuclear factor (NF)-κB signaling.

Protective effects of matrine on experimental autoimmune encephalomyelitis via regulation of ProNGF and NGF signaling.

Inflammation, demyelination, oligodendrocyte (OLG) death, and axonal degeneration are primary characteristics of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). OLGs generate myelin sheaths that surround axons, while damage to OLGs leads to demyelination and neurological functional deficit. Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has been recently found to effectively ameliorate clinical signs in EAE. Its therapeutic mechanism has, however, not been completely elucidated. In the present study, we found that MAT retarded the disease process, attenuated the clinical severity of EAE rats, ameliorated inflammation and demyelination, and suppressed the apoptosis of OLGs in the central nervous system (CNS) of EAE rats. In addition, MAT markedly blocked increased expression of the proNGF-p75(NTR) death signaling complex, which is known to mediate OLG death in EAE animals. At the same time, MAT also prevented a decrease in the levels of NGF and its receptor TrkA, which together mediate the cell survival pathway and differentiation of OLGs. ProNGF, NGF, and the downstream effector proteins play an important role in the growth, differentiation, and apoptosis of OLGs as well as the reparative response to neuronal damage. These findings thus indicate that MAT improves clinical severity of EAE in part by reducing OLG apoptosis via restoring the ratios of proNGF:NGF and the respective receptors p75(NTR):TrkA in vivo. Taken together, these results suggest that MAT may be a promising agent for MS treatment based on its protective effect on OLGs.

Therapeutic effect of baicalin on experimental autoimmune encephalomyelitis is mediated by SOCS3 regulatory pathway.

Natural compounds derived from medicinal plants have long been considered a rich source of novel therapeutic agents. Baicalin (Ba) is a bioactive flavonoid compound derived from the root of Scutellaria baicalensis, an herb widely used in traditional medicine for the treatment of various inflammatory diseases. In this study, we investigate the effects and mechanism of action of Ba in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Ba treatment effectively ameliorated clinical disease severity in myelin oligodendrocyte glycoprotein (MOG)35-55 peptide-induced EAE, and reduced inflammation and demyelination of the central nervous system (CNS). Ba reduced infiltration of immune cells into the CNS, inhibited expression of proinflammatory molecules and chemokines, and prevented Th1 and Th17 cell differentiation via STAT/NFκB signaling pathways. Further, we showed that SOCS3 induction is essential to the effects of Ba, given that the inhibitory effect of Ba on pathogenic Th17 responses was largely abolished when SOCS3 signaling was knocked down. Taken together, our findings demonstrate that Ba has significant potential as a novel anti-inflammatory agent for therapy of autoimmune diseases such as MS.

Matrine ameliorates experimental autoimmune encephalomyelitis by modulating chemokines and their receptors.

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune diseases characterized by immune-mediated neuroinflammation, demyelination and neurodegeneration of the central nervous system (CNS). While matrine (MAT), a monomer that is used in traditional Chinese medicine as an anti-inflammatory treatment, delayed onset and ameliorated severity of EAE, the underlying mechanisms have not been fully elucidated. In this study, we investigated the relationship between the clinical effect of MAT and the levels of certain important chemokines/chemokine receptors. Our results showed that attenuated severity of EAE resulting from MAT treatment was positively correlated with the reduction of CCL2 and CXCL10 levels in the periphery and the CNS; both of these chemokines play a crucial role in the recruitment and accumulation of inflammatory cells, especially monocytes/macrophages and T cells, into the CNS. The levels of their corresponding receptors, CCR2 and CXCR3, were also significantly reduced after MAT treatment. Taken together, our data indicate that MAT may be an effective immunomodulatory therapeutic approach for MS/EAE by countering the immune cell recruitment mechanisms.

Matrine protects neuro-axon from CNS inflammation-induced injury.

Neuro-axonal injury in the central nervous system (CNS) is one of the major pathological hallmarks of experimental autoimmune encephalomyelitis (EAE), an experimental model of multiple sclerosis (MS). Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has recently been shown to effectively suppress EAE through an anti-inflammatory mechanism. However, whether MAT can also protect myelin/axons from damage is not known. In the present study we show that, while untreated rats developed severe clinical disease, CNS inflammatory demyelination, and axonal damage, these clinical and pathological signs were significantly reduced by MAT treatment. Consistently, MAT treatment reduced the concentration of myelin basic protein in serum and downregulated expression of ß-amyloid (Aß) and B-site APP cleaving enzyme 1 (BACE-1) in the CNS. Further, the CNS of MAT-treated rats exhibited increased expression of brain-derived neurotrophic factor (BDNF), an important factor for neuronal survival and axonal growth. Together, these results demonstrate that MAT effectively prevented neuro-axonal injury, which can likely be attributed to inhibiting risk factors such as BACE-1 and upregulating neuroprotective factors such as BDNF. We conclude that this novel natural reagent, MAT, which effectively protects neuro-axons from CNS inflammation-induced damage, could be a potential candidate for the treatment of neurodegenerative diseases such as MS.

Matrine suppresses production of IL-23/IL-17 and ameliorates experimental autoimmune encephalomyelitis.

Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has been suggested to possess immunomodulatory characteristics; however, whether it is effective in multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS), is not known. Our aim was to bridge this gap by investigating the possible therapeutic effects of MAT on experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We have found that, compared to the untreated controls, MAT-treated rats showed a significant decrease in clinical scores, in CNS infiltration of inflammatory cells (including CD4(+), CD8(+) T cells and macrophages) and demyelination. Furthermore, serum levels of IL-23 and IL-17 showed a marked reduction after MAT treatment, particularly in rats treated with higher doses of MAT. This study demonstrates that administration of MAT, as a natural compound, might be a novel therapy for autoimmune disorders such as MS.