Effects of subconjunctival administration of anti-high mobility group box 1 on dry eye in a mouse model of Sjӧgren's syndrome.

Kyeong Hwan Kim,Hyun Jeong Jeong,Joo Youn Oh,Won Ryang Wee,Mee Kum Kim,Jin Suk Ryu,Dong Hyun Kim,Yu Jeong Kim,Fu-Shin Yu

doi:10.1371/journal.pone.0183678

Abstract

PurposeExtracellular high mobility group box 1 (HMGB1) acts as a damage associated molecular pattern molecule through the Toll-like receptor to promote autoreactive B cell activation, which may be involved in the pathogenesis of Sjӧgren’s syndrome. The aim of this study was to investigate the effect of subconjunctival administration of anti-HMGB1 on dry eye in a mouse model of Sjӧgren’s syndrome.MethodsTen weeks-old NOD.B10.H2b mice were subconjunctivally injected with 0.02 to 2 μg of anti-HMGB1 antibodies or PBS twice a week for two consecutive weeks. Tear volume and corneal staining scores were measured and compared between before- and after-treatment. Goblet cell density was counted in PAS stained forniceal conjunctiva and inflammatory foci score (>50 cells/focus) was measured in extraorbital glands. Flow cytometry was performed to evaluate the changes in BrdU+ cells, IL-17-, IL-10-, or IFNγ-secreting cells, functional B cells, and IL-22 secreting innate lymphoid cells (ILC3s) in cervical lymph nodes. The level of IL-22 in intraorbital glands was measured by ELISA.ResultsInjection of 2 μg or 0.02 μg anti-HMGB1 attenuated corneal epithelial erosions and increased tear secretion (p<0.05). Goblet cell density was increased in 0.2 μg and 2 μg anti-HMGB1-treated-mice with marginal significance. The inflammatory foci score, and the number of BrdU+ cells, IL-17-, IL-10-, IFNγ-secreting cells, and functional B cells did not significantly change following anti-HMGB1 treatment. Surprisingly, the percentage of ILC3s was significantly increased in the draining lymph nodes (p<0.05), and the expression of IL-22 was significantly increased in the intraorbital glands (p<0.05) after administration of 2 μg anti-HMGB1.ConclusionThis study shows that subconjunctival administration of anti-HMGB1 attenuates clinical manifestations of dry eye. The improvement of dry eye may involve an increase of ILC3s, rather than modulation of B or plasma cells, as shown using a mouse model of Sjӧgren’s syndrome.

Highlights

Sjogren’s syndrome represents one of the most devastating examples of autoimmune dry eye, which is involved in multiple pathological mechanisms and causes severe discomfort and visual disturbance
This study shows that subconjunctival administration of anti-high-mobility group box 1 (HMGB1) attenuates clinical manifestations of dry eye
The improvement of dry eye may involve an increase of ILC3s, rather than modulation of B or plasma cells, as shown using a mouse model of Sjogren’s syndrome

Summary

Introduction

Sjogren’s syndrome represents one of the most devastating examples of autoimmune dry eye, which is involved in multiple pathological mechanisms and causes severe discomfort and visual disturbance. Many studies have shown the importance of type I interferon secreted by plasmacytoid dendritic cells, B cell responses, extracellular high-mobility group box 1 (HMGB1) and IL-17 pathways in Sjogren’s syndrome [1,2,3]. HMGB1 has three conserved redox-sensitive cysteines (C23, C45, C106), two located at positions 23 and 45 in the A box and one at position 106 in the B box. Extracellular HMGB1, which is passively released from necrotic cells or actively secreted by macrophages and dendritic cells, is a crucial cytokine that mediates the response to infection, injury, and inflammation, including autoimmune diseases such as Sjogren’s syndrome [2, 3, 8]. Apoptosis-induced extracellular HMGB1, in which all cysteines are oxidized, or cysteine 106 is oxidized, does not exhibit proinflammatory or chemotactic activities [7]

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