Artemisinin Analogue SM934 Ameliorates Murine Experimental Autoimmune Encephalomyelitis through Enhancing the Expansion and Functions of Regulatory T Cell

Xin Li,Feng-Hua Zhu,Xiao-Qian Yang,Tian-Tian Li,Li-Fei Hou,Xiao-Hui Zhang,Jian-Ping Zuo,Wei Tang,Hossam M Ashour

doi:10.1371/journal.pone.0074108

Abstract

BackgroundArtemisinin analogue SM934 was previously reported to possess immunosuppressive properties. The aim of this study was to determine the effects and the underlying mechanisms of SM934 in murine experimental autoimmune encephalomyelitis (EAE).MethodsFemale C57BL/6 mice immunized with MOG35–55 were treated with or without SM934, then the clinical scores and other relevant parameters were assessed. Th1, Th17 and regulatory T (Treg) cell profiles were determined through ELISA, qRT-PCR, flow cytometry and BrdU incorporation assay. The effects of SM934 on Th1, Th17 and Treg cells differentiation were explored through intracellular staining and flow cytometry examination.Results In vivo, administration of SM934 significantly inhibited the development of EAE and suppressed the elevation of serum IL-17. Ex vivo, upon antigen-recall stimulation, IL-2, IFN-γ, IL-17 and IL-6 production were decreased, whereas IL-10 and TGF-β production were increased from the splenocytes isolated from SM934-treated mice. Consistently, both flow cytometry and qRT-PCR results showed that SM934 treatment significantly increased the Treg, while strongly suppressed the Th17 and Th1, responses in the peripheral. Furthermore, in the spinal lesion, SM934 treatment dramatically decreased the infiltration of CD4+ T cells, within which the Treg cells percentage was enlarged, whereas the Th17, but not Th1 percentage, was significantly decreased comparing with the vehicle-treated groups. Finally, both BrdU incorporation and in vitro Treg differentiation assays revealed that SM934 treatment could directly promote the expansion of Treg cells in vivo and in vitro.ConclusionTaken together, this study demonstrated that SM934 treatment could ameliorate the murine EAE disease, which might be mediated by inducing Treg differentiation and expansion.

Highlights

Multiple sclerosis (MS) is an inflammatory disease in which the myelin sheath around the axons of brain and spinal cord are damaged that lead to demyelination
It was recognized that IFN-c-producing Th1 cells were predominant pathogenic cells in MS and EAE [2], and its key role was supported by establishing EAE model upon adoptive transfer of IL-12 polarized Th1 cells [3]
Mice deficient in Th1associated molecules, such as IFN-c[4], IL-12Rb2 [5] or IL-12p35 [6] were more susceptible to EAE, while IL-12p40 deficient mice were resistant to disease [7], which challenged the predominance of Th1 in EAE pathogenesis

Summary

Introduction

Multiple sclerosis (MS) is an inflammatory disease in which the myelin sheath around the axons of brain and spinal cord are damaged that lead to demyelination. EAE, a classical animal model of MS, which is characterized by abnormal inflammatory cells infiltrating into the central nervous system (CNS), initiating the lesion formation and the demyelination of neuron axon [1]. It was recognized that IFN-c-producing Th1 cells were predominant pathogenic cells in MS and EAE [2], and its key role was supported by establishing EAE model upon adoptive transfer of IL-12 polarized Th1 cells [3]. The discovery of IL-23, which shares the IL-12p40 common subunit with IL-12, together with the identification of IL-17-producing CD4+ T cells (Th17), deepened the understanding of pathogenesis in EAE. Mice deficient in IL23p19 subunit are completely resistant to EAE [8] and display defects in the Th17 compartment [9]. The aim of this study was to determine the effects and the underlying mechanisms of SM934 in murine experimental autoimmune encephalomyelitis (EAE)

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