NAD+ improved experimental autoimmune encephalomyelitis by regulating SIRT1 to inhibit PI3K/Akt/mTOR signaling pathway.

Jinli Wang,Ning Zhang,Jueqiong Wang,Li Guo,Bin Li,Xueqin Song,Guojun Tan,Pengtao Sun

doi:10.18632/aging.203781

Abstract

Objective: To investigate the effect of NAD+ on thymus autophagy in experimental autoimmune encephalomyelitis (EAE) mice through SIRT1.Methods: Bioinformatic analysis was used to identify hub genes. Forty female C57BL/6 mice were randomly divided into 4 groups: control, EAE, NAD+, and NAD+ +SIRT1 inhibitor (SIRT-IN-3) groups and SIRT1 group. The NAD+ group and SIRT1 inhibitor group were treated with NAD+ drug and fed for 4 weeks. The neurological function scores were evaluated weekly. The thymus tissues of wild-type mice were removed, ground and filtered into single-cell suspension. MOG 35-55 (1 μg/mL) was given to primary thymic epithelial cells (TECs) to induce EAE model in vitro. The expression of LC-3A/B was observed by immunofluorescence. The expressions or the activation/phosphorylation of associated proteins were detected by Western blot.Results: Enrichment analysis showed PI3K-Akt-mTOR and autophagy pathway were main terms in EAE diseases, and the relationship between NAD+ and SIRT1. The activation of p-PI3K, p-Akt and p-mTOR were the highest in the EAE group consistent with decreased P62, Beclin1, LC-3A/B and SIRT1, and NAD+ reversed these results, furthermore SIRT1 inhibitor: SIRT-IN3 weakened the NAD+’ effects in both in vivo and in vitro experiments. Immunofluorescence study in vivo and in vitro were accord with the results of western blot.Conclusions: NAD+ exerted a protective effect on EAE mice by inhibiting PI3K/Akt/mTOR signaling pathway through SIRT1 in TECs, and prevented EAE mice from sustained damage.

Highlights

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS), which is pathologically characterized by chronic inflammatory demyelinating, reactive proliferation of astrocytes and axon damage to varying degrees
Under fluorescence www.aging-us.com microscope, immunofluorescence staining were carried on in the thymus, our results showed that the fluorescence intensity of LC-3A/B in EAE group was the highest, followed by NAD+ + Silence Information Regulator 1 (SIRT1) inhibitor group, NAD+ group, and control group (Figure 4)
Thymus is the major central immune organ and responsible for T cell development and maturation, T cells recognize our own antigens in thymic epithelial cells (TECs), which result in the clonal deletion or clonal non-response of autoreactive T cells and lead to autoimmune tolerance [3, 4]

Summary

Introduction

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS), which is pathologically characterized by chronic inflammatory demyelinating, reactive proliferation of astrocytes and axon damage to varying degrees. Most commonly occur in women aged between 20 and 40, and their clinical manifestations are visual impairment, ataxia, walking difficulties, paresthesia, sexual dysfunction, urinary and feces disorders, as well as anxiety, depression, insomnia and other psychiatric symptoms [1, 2]. Relevant studies have shown that MS may be caused by immune www.aging-us.com disorders caused by the interaction of genetic factors and environmental factors [5, 6]. Further study on the etiology and mechanism of MS is of great importance for the radical cure of this disease

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