Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou 325035, China.
Department of Transfusion, The West China Hospital, Sichuan University, 37 Guoxue Lane, Wuhou District, Chengdu 610041, China.
Sci Total Environ. 2022 Dec 1;850:158040. doi: 10.1016/j.scitotenv.2022.158040. Epub 2022 Aug 13.
As a ubiquitous environmental estrogen-disrupting chemical, triclosan (TCS) can induce severe osteotoxicity; however, the underlying molecular mechanisms remain uncertain. Herein, we evaluated the toxic effects of TCS on the development of cartilage and osteogenesis in 5-dpf zebrafish. Under TCS exposure from 62.5 to 250 μg/L, several osteodevelopmental malformations were observed, such as defect of craniofacial cartilage, pharyngeal arch cartilage dysplasia, and impairments on skeletal mineralization. Further, the morphology of mature chondrocytes became swollen and deformed, their number decreased, nucleus displacement occurred, and most immature chondrocytes were crowded at both ends of ceratobranchial. SEM observation of larval caudal fin revealed that, the layer of collagen fibers and the mineralized calcium nodules were significantly decreased, with the collagen fibers becoming shorter upon TCS exposure. The activity of bone-derived alkaline phosphatase significantly reduced, and marker functional genes related to cartilage and osteoblast development were abnormally expressed. RNA-seq and bioinformatics analysis indicated, that changes in marker genes intimately related to the negative regulation of miR-30c-5p overexpression targeted by TCS, and the up-regulation of miR-30c induced bone developmental defects by inhibiting the bone morphogenetic protein (BMP) signaling pathway. These findings were confirmed by artificially intervening the expression of miR-30c and using BMP pathway agonists in vivo. In sum, TCS induced osteototoxicity by targeting miR-30c up-regulation and interfering in the BMP signaling pathway. These findings enhance mechanistic understanding of TCS-induced spontaneous bone disorders and bone metastatic diseases. Further research is necessary to monitor chronic TCS-exposure levels in surrounding environments and develop relevant safety precautions based on TCS environmental risk.
三氯生（TCS）作为一种普遍存在的环境雌激素破坏化学物质，可诱导严重的骨毒性；然而，其潜在的分子机制尚不清楚。在此，我们评估了 TCS 对 5 日龄斑马鱼软骨和骨发生发育的毒性作用。在 TCS 暴露浓度为 62.5 至 250μg/L 时，观察到几种骨发育畸形，如颅面软骨缺陷、咽弓软骨发育不良以及骨骼矿化受损。此外，成熟软骨细胞的形态变得肿胀和变形，数量减少，核移位发生，大多数未成熟软骨细胞在鳃弓软骨拥挤在两端。幼鱼尾鳍的扫描电镜观察显示，胶原纤维层和矿化钙结节明显减少，胶原纤维在 TCS 暴露后变短。骨源性碱性磷酸酶的活性显著降低，与软骨和成骨细胞发育相关的标记功能基因异常表达。RNA-seq 和生物信息学分析表明，TCS 靶向 miR-30c-5p 过表达的负调控密切相关的标记基因发生变化，miR-30c 的上调通过抑制骨形态发生蛋白（BMP）信号通路引起骨发育缺陷。这些发现通过人工干预 miR-30c 的表达并在体内使用 BMP 通路激动剂得到了证实。总之，TCS 通过靶向 miR-30c 的上调和干扰 BMP 信号通路引起骨毒性。这些发现增强了对 TCS 诱导自发骨疾病和骨转移疾病的机制理解。有必要进一步研究周围环境中慢性 TCS 暴露水平，并根据 TCS 环境风险制定相关安全预防措施。
