Thyrocyte interleukin-18 expression is up-regulated by interferon-γ and may contribute to thyroid destruction in Hashimoto's thyroiditis.

Abstract

Interferon-γ (IFN-γ) has a direct role in thyroid destruction in autoimmune thyroiditis. Interleukin-18 (IL-18), a pro-inflammatory cytokine with potent IFN-γ inducing activities, may play an important role in Th1-mediated autoimmune diseases. The purpose of this study was to characterize the expression and localization of IL-18 in the thyroid tissues of Hashimoto's thyroiditis (HT) and to investigate the effect of IFN-γ on IL-18 expression in isolated human thyroid follicular cells (TFCs). Thyroid tissues obtained from six euthyroid patients with HT and six control subjects were used to detect IL-18 expression by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining. Human TFCs were isolated and incubated for 48 h with or without IFN-γ, tumour necrosis factor-α (TNF-α) or IL-1β. IL-18 expression was analysed by RT-PCR, immunofluorescent double staining and western blot. We found that IL-18 expression was increased in the thyroid tissues of HT compared with control thyroid tissues. TFCs were major cell types expressing IL-18 in the thyroid tissues of HT. IL-18 was constitutively expressed in isolated human TFCs, and the expression was significantly up-regulated by IFN-γ rather than TNF-α or IL-1β. Western bolt revealed that a 24-kDa band corresponding to pro-IL-18 was broadened in the lysates of IFN-γ-treated TFCs. Our results demonstrated that IL-18 expression is up-regulated in the TFCs of HT patients and in primary human TFCs exposed to IFN-γ. Therefore, intrathyroidal interaction between IL-18 and IFN-γ may have a role in promoting the local immune response, which contributes to the thyroid destruction seen in HT.

• Authors: Zhe Liu, Haining Wang, Wenhua Xiao, Chen Wang, Guoqiang Liu, Tianpei Hong
• Journal: International journal of experimental pathology (Int J Exp Pathol) Vol. 91 Issue 5 Pg. 420-5 (Oct 2010) ISSN: 1365-2613 [Electronic] England
• PMID: 20586818 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

Chemical References

• Interleukin-18
• Interleukin-1beta
• Tumor Necrosis Factor-alpha
• Interferon-gamma

Topics

• Adult
• Biopsy
• Cells, Cultured
• Female
• Gene Expression (immunology)
• Hashimoto Disease (immunology, metabolism, pathology)
• Humans
• Interferon-gamma (metabolism)
• Interleukin-18 (genetics, metabolism)
• Interleukin-1beta (metabolism)
• Male
• Middle Aged
• Thyroid Gland (immunology, metabolism, pathology)
• Tumor Necrosis Factor-alpha (metabolism)
• Up-Regulation (immunology)