MiRNA Regulation of MIF in SLE and Attenuation of Murine Lupus Nephritis With miR-654.

Yang Tu,Suli Wang,Ruru Guo,Liangjing Lu,Richard Bucala,Jia Li,Jun Deng,Lin Leng

doi:10.3389/fimmu.2019.02229

Abstract

Objective: Macrophage Migration Inhibitory Factor (MIF) is involved in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). MicroRNAs (miRNAs) play important roles in LN but whether specific miRNAs regulate the expression of MIF in LN is unknown. We explore specific miRNAs that can regulate MIF expression, and investigate miR-654 for the treatment of experimentally-induced murine lupus nephritis.Methods: Sera samples from 24 SLE patients and 24 controls were collected to measure the MIF concentration and its correlation with disease activity. A luciferase reporter assay was used to explore the target of miR-654. ELISA was used to detect the downstream cytokines regulated by miR-654 and MIF. Western blot was applied to measure the impact of miR-654 inhibition on downstream MIF signaling. The therapeutic efficacy of miR-654 was tested in the pristine-induced lupus mouse model. We further measured miR-654 expression and analyzed its relationship with MIF expression in SLE patients.Results: The serum MIF level was increased in SLE patients (p < 0.001) and positively correlated with the SLEDAI score (r = 0.5473; p = 0.0056). MiR-654 inhibited MIF and downstream inflammatory cytokine production by selectively inhibiting the phosphorylation of ERK and AKT. Activation of miR-654 reduced IL-1β, IL-6, IL-8, and TNF-α production, reduced gomerulonephritis, and decreased MIF, IgG, and C3 expression in murine lupus glomeruli. Furthermore, MIF was negatively correlated with miR-654 expression (r = −0.4644; p = 0.0222) in SLE patients.Conclusion: MiR-654 negatively correlated with MIF and disease activity in patients with SLE. MiR-654 inhibits MIF expression via binding to MIF 3'UTR, selectively suppresses the phosphorylation of ERK and AKT, and reduces downstream inflammatory cytokine production. In vivo miR-654 treatment decreases MIF and downstream cytokine production and ameliorates murine lupus nephritis.

Highlights

Systemic lupus erythematosus (SLE) is a prototypic immune complex disease that affects multiple organ systems
Macrophage migration inhibitory factor (MIF) mRNA was more highly expressed in Peripheral blood mononuclear cells (PBMC) from SLE patients than from healthy controls (P < 0.001, Figure 1A), and serum MIF
It is well-known that steroids affect MIF levels, so we analyzed the dosage of steroids at the time of blood collection in all patients, and found that MIF expression is positively related with the dosage of steroids (P < 0.05) (Figure 1H)

Summary

Introduction

Systemic lupus erythematosus (SLE) is a prototypic immune complex disease that affects multiple organ systems. The immunologic features of SLE include autoantibodies directed against nuclear components and elevated pro-inflammatory cytokines, such as type I interferon (IFN), IL-1β, IL-6, IL-8, TNF-α, and BAFF [1]. Clinical interventions targeting multiple mediators such as IFNα, IL-1β, TNF-α, IL-6, or BAFF have been largely disappointing [2], suggesting that other effector pathways may play a more dominant role in SLE pathogenesis or disease manifestations [3, 4]. Macrophage migration inhibitory factor (MIF) and its receptors are expressed in elevated levels by different cell types in SLE [5], and circulating MIF level correlates with disease activity [6]. MIF binds to a receptor complex comprising CD74 and CD44 to activate the phosphorylation of ERK and AKT, leading to the expression of pro-inflammatory cytokines such as IL-1β, IL-6, IL-8, TNF-α, and others [9– 11]. The precise mechanisms underlying MIF expression and pathologic function remain poorly understood in SLE

Methods

Results

Conclusion