Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
Radiat Res. 2020 Apr;193(4):383-393. doi: 10.1667/RR15550.1. Epub 2020 Feb 25.
The functions and molecular mechanism of circRNAs in the development of radiation-induced liver disease (RILD) remain largely unknown. The goal of this study was to explore the expression and potential role of a new circular RNA, named circTUBD1, in irradiated and lipopolysaccharide (LPS)-stimulated human hepatic stellate cell (HSC) line LX-2 cells. The expression of circTUBD1 was significantly upregulated in irradiated and LPS-stimulated LX-2 cells compared to non-treated LX-2 cells. To explore the functions of circTUBD1, small interfering RNAs targeting circTUBD1 were designed. Silencing circTUBD1 inhibited proliferation, promoted apoptosis of LX-2 cells, and significantly decreased the expression level of pro-inflammatory cytokines, including IL-1β, IL-6 and TNF-α in irradiated and LPS-stimulated LX-2 cells. Mechanistic analysis suggested that circTUBD1 acted as the miR-146a-5p sponge to affect pro-inflammatory cytokine production through regulating expression of Toll-like receptor 4 (TLR4), interleukin receptor-associated kinase 1 (IRAK1), tumor necrosis factor receptor-associated factor-6 (TRAF6), and phosphorylation of nuclear factor-kappa B (pNF-κB) in irradiated and LPS-stimulated LX-2 cells. To our knowledge, this is the first study to show that circTUBD1 acts as a miR-146a-5p sponge to affect the viability and pro-inflammatory cytokine production of LX-2 cells through the TLR4 pathway, suggesting that circTUBD1 is a potential target for RILD therapy.
环状 RNA circTUBD1 通过调控 TLR4 信号通路影响脂多糖诱导的肝星状细胞增殖和炎症反应
环状 RNA 在辐射诱导的肝疾病（RILD）中的功能和分子机制在很大程度上尚不清楚。本研究旨在探索一种新的环状 RNA，circTUBD1，在辐照和脂多糖（LPS）刺激的人肝星状细胞（HSC）系 LX-2 细胞中的表达及其潜在作用。与未处理的 LX-2 细胞相比，辐照和 LPS 刺激的 LX-2 细胞中 circTUBD1 的表达明显上调。为了探讨 circTUBD1 的功能，设计了针对 circTUBD1 的小干扰 RNA。沉默 circTUBD1 抑制了 LX-2 细胞的增殖，促进了其凋亡，并显著降低了辐照和 LPS 刺激的 LX-2 细胞中促炎细胞因子（包括 IL-1β、IL-6 和 TNF-α）的表达水平。机制分析表明，circTUBD1 作为 miR-146a-5p 的海绵，通过调节 Toll 样受体 4（TLR4）、白细胞介素受体相关激酶 1（IRAK1）、肿瘤坏死因子受体相关因子-6（TRAF6）和核因子-κB（pNF-κB）的表达，影响辐照和 LPS 刺激的 LX-2 细胞中促炎细胞因子的产生。据我们所知，这是第一项表明 circTUBD1 通过 TLR4 通路作为 miR-146a-5p 海绵影响 LX-2 细胞活力和促炎细胞因子产生的研究，表明 circTUBD1 是 RILD 治疗的潜在靶点。
