PDF(Pubmed)
Abstract：
Plastic accumulation in the environment is rapidly increasing, and nanoplastics (NP), byproducts of environmental weathering of bulk plastic waste, pose a significant public health risk. Particles may enter the human body through many possible routes such as ingestion, inhalation, and skin absorption. However, studies on NP penetration and accumulation in human skin are limited. Loss or reduction of the keratinized skin barrier may enhance the skin penetration of NPs. The present study investigated the entry of NPs into a human skin system modeling skin with compromised barrier functions and cellular responses to the intracellular accumulations of NPs. Two in vitro models were employed to simulate human skin lacking keratinized barriers. The first model was an ex vivo human skin culture with the keratinized dermal layer (stratum corneum) removed. The second model was a 3D keratinocyte/dermal fibroblast cell co-culture model with stratified keratinocytes on the top and a monolayer of skin fibroblast cells co-cultured at the bottom. The penetration and accumulation of the NPs in different cell types were observed using fluorescent microscopy, confocal microscopy, and cryogenic electron microscopy (cryo-EM). The cellular responses of keratinocytes and dermal fibroblast cells to stress induced by NPs stress were measured. The genetic regulatory pathway of keratinocytes to the intracellular NPs was identified using transcript analyses and KEGG pathway analysis. The cellular uptake of NPs by skin cells was confirmed by imaging analyses. Transepidermal transport and penetration of NPs through the skin epidermis were observed. According to the gene expression and pathway analyses, an IL-17 signaling pathway was identified as the trigger for cellular responses to internal NP accumulation in the keratinocytes. The transepidermal NPs were also found in co-cultured dermal fibroblast cells and resulted in a large-scale transition from fibroblast cells to myofibroblast cells with enhanced production of α-smooth muscle actin and pro-Collagen Ia. The upregulation of inflammatory factors and cell activation may result in skin inflammation and ultimately trigger immune responses.
摘要：
塑料在环境中的积累正在迅速增加，和纳米塑料（NP），散装塑料废物的环境风化副产品，构成重大公共卫生风险。颗粒可以通过许多可能的途径进入人体，例如摄入，吸入,和皮肤吸收。然而,关于NP在人体皮肤中的渗透和积累的研究是有限的。角质化皮肤屏障的丧失或减少可增强NP的皮肤渗透。本研究调查了NP进入人类皮肤系统的过程，该系统模拟了屏障功能受损的皮肤和细胞对NP细胞内积累的反应。采用两种体外模型模拟缺乏角化屏障的人皮肤。第一个模型是去除了角化真皮层(角质层)的离体人皮肤培养物。第二模型是3D角质形成细胞/真皮成纤维细胞共培养模型,在顶部具有分层的角质形成细胞,在底部具有单层的皮肤成纤维细胞共培养。使用荧光显微镜观察NPs在不同细胞类型中的渗透和积累，共聚焦显微镜，和低温电子显微镜（cryo-EM）。测量角质形成细胞和真皮成纤维细胞对由NP应激诱导的应激的细胞反应。使用转录物分析和KEGG途径分析鉴定角质形成细胞到胞内NP的遗传调控途径。通过成像分析证实皮肤细胞对NP的细胞摄取。观察到NPs通过皮肤表皮的经表皮运输和渗透。根据基因表达和通路分析，IL-17信号传导途径被鉴定为细胞对角质形成细胞内部NP积累的反应的触发因素。在共培养的真皮成纤维细胞中也发现了跨表皮NP，并导致从成纤维细胞到成肌纤维细胞的大规模转变，并增加了α-平滑肌肌动蛋白和前胶原蛋白Ia的产生。炎症因子的上调和细胞活化可导致皮肤炎症并最终引发免疫应答。
