Mechanism Of Bioactivities Of Nanoparticles Mediated By Denatured Protein Corona

Epidemiological studies have shown that long-term exposure of fine particles,including particulate matter 2.5(PM2.5)and cigarette smoke particles(CSP),could lead to lung cancer,asthma and cardiovascular diseases.Engineering nanomaterials,such as iron oxide particles,gold particles and carbon particles have potential side effects in biomedical research and applications.The physical and chemical properties of nanoparticles(NPs)determine its toxic effects to a certain extent,while many particles with different physical and chemical properties can cause similar cytotoxicity or damage,such as apoptosis,inflammation activation,oxidative stress and so on.The interaction between nanomaterials with different properties and biological systems may produce a common biological signal.Exploring the source and mechanism of these common biological signals is expected to clarify the biological behavior of particles in the body.Furthermore,it provides theoretical guidance and new targets for predicting and effectively interfering with the biotoxicity of nanoparticles.The biological function of NPs in vivo is determined by the corona formed on its surface,which is a protein-based biological macromolecular layer formed by the adsorption of biomolecules on particles entering the body.The protein corona contains many functional molecules such as cytokines and enzymes.The corona produces a new interface between the surface of the particles and the biological system,and it is considered to be the biometric label of the particles in the body.Under the influence of different physiological environment and the properties of nanomaterials,the composition and structure of the corona are highly dynamic,while some molecules can be stably adsorbed on the surface of particles and hold its function.According to previous studies,it has been found that nanomaterials with different properties can produce similar biological activities in different physiological environments.Therefore,certain components might ubiquitously exist on the coronas surrounding these NPs,mediating signal activation in cell.Furthermore,these signals should be recognized and activated in the cytosol through endosomal escape,because NPs that are internalized by either endocytic or non-endocytic routes and confined in the endosome are unlikely to trigger the strong cellular responses.Based on the above assumptions,we infer that some molecules,commonly found in corona formed on different kinds of NPs,can interact with cytoplasmic components and trigger same biological signals.These signals are the basis for the same toxic and biological effects of different nanomaterials.In this study,we found that the denatured protein in the corona,as the common signals of different NPs,triggered the cellular unfolded protein response(UPR)and cellular response mediated by heat shock protein 90 kDa ? class B member 1(Hsp90ab1),based on proteomic analysis,biochemical analysis,and studies in cell models and animal models.First of all,we collated the published data of liquid chromatography mass spectrometry(LC-MS)for the coronas formed on different nanoparticles(NPs)and analyzed the proteomics systematically.At the same time,particles from different sources and physical and chemical properties were selected,including PM2.5,CSP,iron-cobalt-nickel alloy NPs(FeCoNiNPs),iron oxide NPs(Fe3O4NPs),carbon NPs(CNPs),silica NPs(SiO2NPs)and gold NPs(AuNPs),incubated with cytoplasmic protein(CP)followed by LC-MS analysis.Proteomic analysis showed that UPR-related proteins and chaperones were highly enriched in the protein coronas of many kinds of NPs.The heat maps and western blotting analysis of chaperones showed that Hsp90ab1 largely existed on all particles.According to the cellular experiments,the NPs-corona complex formed a structure similar to "aggresomes" in cells,which is a typical phenomenon in cellular UPR.The enrichment of chaperones and UPR activation are probably caused by misfolded protein induced by adsorption of NPs.By means of gel electrophoresis,circular dichroism and the binding of Hsp90ab1 to the denatured protein corona,it was found that PM2.5,CSP,FeCoNiNPs and Fe3O4NPs could denature the protein molecules through strong adsorption.This effect is closely related to the surface properties and particle size of the particles.From the above results,it can be inferred that the recruited Hsp90ab1 by denatured protein corona and the induced UPR may be the key signals to mediate the cellular response of NPs.The Hsp90ab1 is highly expressed in cells and is involved in regulating many signal pathways.Gene expression profile analysis of many kinds of cells showed that UPR,inflammation and epithelial-mesenchymal transformation(EMT)pathway were activated,which were closely related to Hsp90ab1.Further cellular experiments showed that Fe3O4NPs and PM2.5 triggered the inflammation,EMT and the disruption of cellular barrier integrity through the heat shock response(HSR),activated by Hsp90ab1.Geldanamycin(GA),an inhibitor of Hsp90ab1,could significantly inhibit these reactions.In the meantime,the acute pulmonary inflammation was activated with mediating of Hsp90ab1 in lung inflammation model induced by Fe3O4NPs and PM2.5,through protein expression analysis,immunofluorescence detection and pathological analysis.Based on the above analysis,Hsp90ab1 recruited by denatured proteins in corona of NPs and the activated UPR,initiated basic intracellular response,which led to common pathological reactions in vivo.This discovery provides a new insight into the mechanism of nanotoxicity and provides reference and theoretical support for the treatment of particle-related diseases.