Identification of Key Pathways and Genes in the Progression of Silicosis Fibrosis Based on WGCNA

Silicosis, induced by inhaling silica particles in workplaces, is one of the most common occupational diseases. The prognosis of silicosis and its consequent fibrosis is extremely poor due to limited treatment modalities and lack of understanding of the disease mechanisms. In this study, a Wistar rat model for silicosis fibrosis was convincingly established by intratracheal instillation of silica (0, 50, 100 and 200 mg/mL, 1 mL) with the evidence of Hematoxylin and Eosin (HE) and Masson staining and the expressions of inflammatory and fibrotic proteins of rats’ lung tissues. RNA of lung tissues of rats exposed to 200 mg/mL silica particles and normal saline for 14 d and 28 d was extracted and sequenced to detect differentially expressed genes (DEGs) and to identify silicosis fibrosis-associated modules and hub genes by Weighted gene co-expression network analysis (WGCNA). Predictions of gene functions and signaling pathways were conducted using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. In this study, it has been demonstrated the promising role of Hippo signaling pathway in silicosis fibrosis, which will be conducive to elucidating the specific mechanism of pulmonary fibrosis induced by silica and to determining molecular initiating event (MIE) and adverse outcome pathway (AOP) of silicosis fibrosis.矽肺（Silicosis）是因在工作场所吸入二氧化硅颗粒所诱发的最常见职业病之一。矽肺及其继发的肺纤维化预后极差，究其原因在于临床治疗手段有限，且当前对该疾病的发病机制认知不足。本研究通过气管内滴注二氧化硅悬液（浓度分别设置为0、50、100、200 mg/mL，给药体积1 mL），成功构建了可靠的矽肺纤维化Wistar大鼠模型（Wistar rat model），并通过苏木精-伊红（Hematoxylin and Eosin, HE）染色、马松（Masson）染色以及检测大鼠肺组织炎症与纤维化蛋白的表达水平对模型进行了验证。随后，本研究提取经200 mg/mL二氧化硅颗粒处理及生理盐水对照处理的大鼠在造模后14天及28天时的肺组织总RNA并进行测序，通过加权基因共表达网络分析（Weighted gene co-expression network analysis, WGCNA）筛选差异表达基因（differentially expressed genes, DEGs），并鉴定与矽肺纤维化相关的基因模块及核心基因（hub genes）。本研究采用基因本体（Gene Ontology, GO）与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）数据库，对差异基因的功能及参与的信号通路进行富集预测。本研究证实Hippo信号通路（Hippo signaling pathway）在矽肺纤维化进程中具有潜在调控价值，该发现有助于阐明二氧化硅诱导肺纤维化的具体分子机制，同时可为明确矽肺纤维化的分子起始事件（molecular initiating event, MIE）与不良结局通路（adverse outcome pathway, AOP）提供关键理论支撑。