Wei Xiaoran, Liu Nan, Song Jian, Ren Chao, Tang Xiaowen, Jiang Wei
Department of Occupational and Environmental Health, School of Public Health, Qingdao University, Qingdao 266071, China; Environment Research Institute, Shandong University, Qingdao 266237, China.
Department of Occupational and Environmental Health, School of Public Health, Qingdao University, Qingdao 266071, China.
Sci Total Environ. 2022 Sep 10;838(Pt 4):156552. doi: 10.1016/j.scitotenv.2022.156552. Epub 2022 Jun 7.
The increasing production and application of silica nanoparticles (SiO NPs) raise public concern regarding their environmental and health risks. The fluidity of the cell membrane is essential for supporting membrane proteins and regulating membrane transport. Changes in membrane fluidity inevitably influence the physiological activities of cells and even cause biological effects. In this study, the effect of SiO NPs on membrane fluidity was studied at 25 °C and 37 °C, and the role of membrane components in SiO NP-membrane interactions was investigated using giant plasma membrane vesicles (GPMVs) isolated from RBL-2H3 cells. SiO NPs cause a more serious membrane fluidity decrease at 37 °C than at 25 °C, which is revealed by the shift of Laurdan fluorescence emission and further quantified via forster resonance energy transfer (FRET) experiments. In addition, after the removal of 75 % cholesterol from the membrane, SiO NPs caused a greater extent of membrane gelation. These results indicate that SiO NPs prefer to interact with membranes that are more dynamic and less densely packed. Moreover, fluorescent experiments confirmed that the existence of phosphatidyl ethanolamine (PE) and phosphoinositide (PI) can mitigate NP-induced membrane gelation. Molecular dynamics simulation further demonstrated that SiO NPs form hydrogen bonds with the terminal of PE or PI but with the -PO- group in the middle of phosphatidylcholine (PC). The bonding that occurs in the terminal gives less restriction of phospholipid movement and a weaker effect on membrane fluidity. This research provides both evidence and mechanisms of SiO NP-induced membrane fluidity changes, which are helpful for understanding cell membrane damage and the biological effects of NPs.
二氧化硅纳米颗粒（SiO NPs）产量和应用的不断增加引发了公众对其环境和健康风险的关注。细胞膜的流动性对于支持膜蛋白和调节膜运输至关重要。膜流动性的变化不可避免地会影响细胞的生理活动，甚至导致生物学效应。在本研究中，在25°C和37°C下研究了SiO NPs对膜流动性的影响，并使用从RBL-2H3细胞分离的巨型质膜囊泡（GPMV）研究了膜成分在SiO NP-膜相互作用中的作用。SiO NPs在37°C时比在25°C时导致更严重的膜流动性降低，这通过Laurdan荧光发射的变化得以揭示，并通过福斯特共振能量转移（FRET）实验进一步量化。此外，从膜中去除75%的胆固醇后，SiO NPs导致更大程度的膜凝胶化。这些结果表明，SiO NPs更喜欢与更具动态性和堆积密度较低的膜相互作用。此外，荧光实验证实磷脂酰乙醇胺（PE）和磷酸肌醇（PI）的存在可以减轻NP诱导的膜凝胶化。分子动力学模拟进一步表明，SiO NPs与PE或PI的末端形成氢键，但与磷脂酰胆碱（PC）中间的-PO-基团形成氢键。在末端发生的键合对磷脂运动的限制较小，对膜流动性的影响较弱。本研究为SiO NP诱导的膜流动性变化提供了证据和机制，有助于理解细胞膜损伤和NP的生物学效应。
