To investigate the role of microRNA (miR)-155 in inflammation in an in-vitro model of Graves' orbitopathy (GO). The expression levels of miR-155 were compared between GO and non-GO orbital tissues. The effects of inflammatory stimulation of interleukin (IL)-1β and tumour necrosis factor alpha (TNF-α) on miR-155 expression on GO and non-GO orbital fibroblasts (OFs) were investigated. The effects of miR-155 mimics and inhibitors of inflammatory proteins and IL-2-inducible T-cell kinase (ITK) expression were examined, along with those related to the knockdown of ITK with siITK transfection on inflammatory proteins. We also examined how ITK inhibitors affect miR-155 expression in GO and non- GO OFs. The expression levels of miR-155 were higher in GO orbital tissues than in non- GO tissue. The overexpression of miR-155 was induced by IL-1β and TNF-α in OFs from GO and non-GO patients. IL-1β-induced IL-6 (ICAM1) protein production was significantly reduced (increased) by miR-155 mimics and inhibitors. The mRNA and protein levels of ITK were downregulated by overexpressed miR-155 via miR-155 mimics. Knockdown of ITK via siITK transfection induced a decrease in the expression levels of ITK, IL-17, IL-6, IL-1β, and TNF-α protein. The expression of miR-155 was significantly downregulated by treatment with ITK inhibitors and Bruton's tyrosine kinase (BTK)/ITK dual inhibitors in a time-dependent manner. Our results indicated a potential relationship between miR-155 and ITK in the context of GO OFs. The overexpression of miR-155 repressed ITK expression and relieved inflammation. Thus, miR-155 appears to have anti-inflammatory effects in GO OFs. This discovery provides a new concept for developing GO treatment therapeutics.
|Issue number||8 August|
|Publication status||Published - 2022 Aug|
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© 2022 Choi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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