Study On Key Toxic Events At The Air-blood Interface Caused By Respiratory Exposure To Metal-based Nanomaterials

The production of metal-based nanomaterials is increasing due to their variety and wide applications.It has been found that nanoparticles released into the environment during their production,processing,transportation,consumption,and recycling.They can reach the lung through respiration then act at the air-blood interface,thereby producing a series of biological effects.The composition of the air-blood interface is complex,in addition to lung epithelial cells and macrophages,there are also various microorganisms.Therefore,the pulmonary effects of nanomaterials are associated with multiple nano-bio interactions,which cannot be entirely mirrored at a specific nano-bio interface.To address the above problems,this study investigated a series of nanobiological effects of metal-based nanomaterials on lung cells and pulmonary microorganisms.Then we analyzed the correlation between the nanobiological effects and pulmonary toxicity in vivo,and explored the key events of respiratory toxicity induced by nanomaterials via machine learning methods.(1)At the cellular level,15 kinds of celluar branching events of 50 typical metalbased nanoparticles(MNPS)on two representative cells(THP-1 and Beas-2B)were investigated.TGF-β and Masson staining images were used as endpoints to evaluate the in vivo pulmonary toxicity effects of MNPS.Pearson correlation coefficient method was used to analyze the correlation between each cellular event and the pulmonary toxicity effects.The results showed that different MNPs have different cellular effects and the correlation coefficients were all less than 0.5.Therefore,single cell branching event could not reflect the in vivo toxicity entirely.The random forest algorithm had the best performance,with the overall prediction accuracy of 91%in the training set and 84%in the test set.According to the model derivation,the key cellular events affecting the pulmonary toxicity induced by metal-based nanomaterials were the metabolic activity of THP-1 and the release of IL-1β,and the metabolic activity of Beas-2B and the release of TGF-β.(2)At the microbial level,the effects of eight kinds of MNPs(Ag、Fe2O3、ZnO、α-Al2O3、CeO2、CuO、SnO2、La2O3)on the in vitro pulmonary microbiota activity were investigated.Further we explored the in vivo toxic effects of the nanoparticles on normal and germ-free mice.At the same time,the components of the microbiota were isolated to analyze the key microbial effects and potential mechanisms of nanoparticles induced pulmonary toxicity.The results showed that silver nanoparticles had the strongest bactericidal activity,which could kill 100%of the lung bacterial flora at the concentration of 125 μg/mL.Moreover it induce significant acute lung inflammation in normal mice.However,removing the lung bacterial flora could significantly reduce the inflammatory effect Further studies showed that silver nanoparticles could induce the death of lung bacteria and DNA release.It induce the pyroptosis of pulmonary macrophages and the release of IL-1β,which triggers pulmonary inflammation.In summary,this study investigated a series of nano-bio interface events of typical MNPs on cells and microorganisms.We found that metabolic activity of THP-1 and Beas-2B,IL-1β release from THP-1 and TGF-β release from Beas-2B were the key cellular events on pulmonary toxicity.The DNA produced via bacterial death is the key microbial effect affecting the lung toxicity.This study not only provides data support and reference for follow-up related research,but also provides new insights for the interpretation of toxicity mechanisms.