Arthritis Res Ther. 2016;18(1):264.

Circulating exosomes from patients with systemic lupus erythematosus induce an proinflammatory immune response.

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제1저자 이주연 · 교신저자 송영욱

PMID 27852323 PMC5112700 DOI 10.1186/s13075-016-1159-y IF 5.4 류마티스내과

소속 (4)

Department of Molecular Medicine and Biopharmaceutical Sciences, BK 21 plus Graduate School of Convergence Science and Technology, and College of Medicine, Medical Research Institute, Seoul National University, Seoul, Korea.
Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Daehak-ro, Jongno-gu, Seoul, 03082, Korea.
Department of Molecular Medicine and Biopharmaceutical Sciences, BK 21 plus Graduate School of Convergence Science and Technology, and College of Medicine, Medical Research Institute, Seoul National University, Seoul, Korea. ysong@snu.ac.kr.
Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Daehak-ro, Jongno-gu, Seoul, 03082, Korea. ysong@snu.ac.kr.

Abstract

BACKGROUND Exosomes are involved in intercellular communication. The aim of this study was to investigate whether circulating exosomes effectively contribute to the inflammatory response in systemic lupus erythematosus (SLE).

METHODS Exosomes were purified from SLE patients and healthy controls (HCs). Healthy peripheral blood mononuclear cells (PBMCs) were stimulated with exosomes isolated from SLE patients and HCs in the presence or absence of Toll-like receptor (TLR) inhibitors. Production of interferon (IFN)-α, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were measured. Correlation between exosome levels and SLE disease activity was examined.

RESULTS The serum exosomes levels were significantly higher in SLE patients than in HCs. SLE exosomes induced a higher production of IFN-α, TNF-α, IL-1β, and IL-6 compared to healthy exosomes. SLE serum that was depleted of exosomes and SLE exosomes that were mechanically disrupted failed to induce any significant cytokine production. Exosome-mediated production of TNF-α, IL-1β, and IL-6 was decreased by the TLR4 antagonist, whereas that of IFN-α was suppressed by the TLR1/2, TLR7, and TLR9 antagonists. Exosome levels correlated with disease activity in SLE patients (rho = 0.846, p = 0.008).

CONCLUSIONS The circulating exosomes are immunologically active and their levels correlate with disease activity in SLE patients. The circulating exosomes might serve as novel biomarkers of SLE disease activity.

Keywords

CytokineExosomeInflammationSystemic lupus erythematosusToll-like receptor

Figures

**Fig. 1** Enriched exosomes in SLE. a The size and shape of purified exosomes were evaluated by TEM imaging. The exosomes were 50–100 nm in size (*arrows*) and had a lipid layer (*insert*). b Systemic lupus erythematosus (*SLE*) patients had higher serum levels of exosomes than healthy controls (*HCs*) by acetylcholinesterase (*AChE*) assay. Both exosome protein markers CD81 (c) and CD63 (d) were higher in SLE than in HC. Data are presented as the median and interquartile range. *p < 0.05, **p < 0.01

**Fig. 2** Cytokine production by exosomes. a Healthy PBMCs were stimulated with exosomes from healthy controls (HC) and systemic lupus erythematosus (*SLE*) patients, and production of IFN-α, TNF-α, IL-1β, and IL-6 were measured. Data are presented as the median and interquartile range. b Cytokine production by SLE exosomes that were mechanically disrupted and SLE serum that was depleted of exosomes relative to SLE exosomes were compared. Data are presented as the median and interquartile range. *p < 0.05, **p < 0.01. *IFN* interferon, IL interleukin, *TNF* tumor necrosis factor

**Fig. 3** Comparison between cytokine production by rheumatoid arthritis and systemic lupus erythematosus. Production of IFN-α (a), TNF-α (b), and IL-6 (c) by the healthy PBMCs after stimulation with exosomes from healthy controls (HC; n = 8), rheumatoid arthritis (RA; n = 8) or systemic lupus erythematosus (*SLE*; n = 8) patients were measured. Data are presented as the median and interquartile range. *p < 0.05, **p < 0.01, ***p < 0.0001. *IFN* interferon, IL interleukin, NS not significant, *TNF* tumor necrosis factor

**Fig. 4** Exosomes from SLE induce secretion of inflammatory cytokines via Toll-like receptors (*TLRs*). a Human PBMCs were incubated with carboxyfluorescein succinimidyl diacetate ester (*CFSE*)-labeled SLE exosomes. Confocal images showed that exosomes (*green*) co-localized with endosomes (*yellow* in the merged images). Nucleus (Hoechst blue), endosome (*red*). b PBMCs (n = 3) were treated with CFSE-labeled SLE exosomes. The percentage of exosome (+) PBMCs increased with time. c PBMCs were stained with Hoechst for nucleus (*blue*) and anti-TLR antibodies (*red*). The exosomes (*green*) co-localized with TLRs (*yellow* in the merged images). *Scale bars* = 10 μm

**Fig. 5** Exosomes from SLE induce secretion of inflammatory cytokines via Toll-like receptors (*TLRs*). Human PBMCs were incubated with SLE exosomes in the presence of specific antagonists to TLR1/2, TLR4, TLR7, and TLR9. After 24 h, levels of IFN-α (a), TNF-α (b), IL-1β (c), and IL-6 (d) were determined. Data are presented as the median and interquartile range.*p < 0.05. *IFN* interferon, IL interleukin, *TNF* tumor necrosis factor

**Fig. 6** Correlation between SLE disease activity and cytokine production by exosomes. a Serum exosome levels correlated significantly with SLE disease activity index 2K (*SLEDAI*) in nine patients with SLE. Production of IFN-α (b), TNF-α (c), IL-1β (d), and IL-6 (e) by the healthy PBMCs after stimulation with SLE exosomes (n = 8) correlated with SLEDAI. P values were generated by using Spearman correlation. *IFN* interferon, IL interleukin, *TNF* tumor necrosis factor

그림 출처: PubMed Central 공개 논문 (PMC5112700)

Comment · 정정

Erratum in Arthritis Res Ther. 2020 May 8;22(1):109. doi: 10.1186/s13075-020-02206-y.

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