Study On The Key Surface Properties Of Functionalized Gold Nanoparticles Regulating The Maturation Of Mouse Bone Marrow-derived Dendritic Cells(BMDCs)

As the most potent antigen presenting cells,dendritic cells(DCs)play key roles in the initiation of immune responses and tolerance induction.To evaluate the immunological effect of nanomaterials on DCs is a vital component of the immunological effect of nanoparticles.On the other hand,since the size of nanomaterials is similar to the natural pathogens and they are easily ingested by DCs,targeting DCs by nanotechnology stands as a promising strategy for disease immunotherapy.A functionalized surface can allow nanomaterial to have new biological properties due to their high surface reactivity.So it is necessary to explore how the nanoparticles' surface chemistry affect the DCs.immune function.Such investigations could provide theoretical basis for not only the design of novel nanomaterials but also the safety of them,accelerating their application in nanomedicine.Recent reports showed that the surface modification modulated the immune function of DCs,however,those researches were restricted to certain individual physicochemical properties.It is urgently needed to investigate the correlation between the surface physicochemical properties and its immunological effects systematically.Based on this,our group designed and synthesized a gold nanoparticle library,which contained 28 gold nanoparticles(GNPs)with diverse surface properties.In this work,we explored how the surface chemistry of GNPs modulate the maturation of DCs.As we all know,the activation of the interferon regulatory factor(IRF)signal pathway and/or NF-?B signal pathway are associated with the DCs maturation.So we screened the library using THP1-DualTM cells and PMA-induced macrophage-like THP1-DualTM cells.THP1-DualTM cells are stably expressing the interferon(IFN)response element and the NF-?B transcriptional response element reporter genes(the secreted Luciferase(LuciaTM)gene and the secreted embryonic alkaline phosphatase(SEAP)gene),which allow the simultaneous study of the NF-?B pathway,by monitoring the activity of SEAP,and the interferon regulatory factor(IRF)pathway,by assessing the activity of LuciaTM.Then we used the computational chemistry method to simulate the structure-activity relationship of GNPs in regulating both IRF and/or NF-?B signaling pathways.Finally,we selected some GNPs to treat mouse bone marrow-derived dendritic cells(BMDCs).The effects of GNPs surface chemistry on maturation of BMDCs were detected by analyzing the levels of cytokine secretion and surface marker protein expression including MHC?,CD80,TNF-? and IL-12 p70.At the same time,the accuracy of the structure-activity relationship prediction model is verified.The results showed that GNPs activate IRF and/or NF-?B signaling pathways in THP1-DualTM cells in a surface chemistry dependent manner;the regulation of IRF pathway in THP1-DualTM cells is most correlated with the electronegativity and hydrophobicity of GNPs surface modification;the regulation of NF-?B signaling pathway in THP1-DualTM cells is most correlated with the partial charges and hydrophobicity of GNPs surface modification;the regulation of IRF pathway in PMA-induced macrophage-like THP1-DualTM cells is most correlated with the accessible van der waals surface area and hydrophobicity of GNPs surface modification.Based on the results,five kinds of GNPs with significant different effects were selected for further study.Among them,GNP7,14 and 16 up-regulate the expression of LuciaTM for more than 4.5-fold and that of SEAP for more than 40-fold in THP1-DualTM cells after 24 h treatment.These GNPs up-regulate the expression of LuciaTM in PMA-induced macrophage-like THP1-DualTM cells for more than 40-fold.In contrast,GNP25 and 27 showed much less effect on the expression of SEAP,but no obvious effect on the LuciaTM.After treatment with the selected GNPs for 24 h,the expression of MHCII,CD80,TNF-? and IL-12 p70 were measured in BMDCs.The results showed that GNP7,14 and 16 induced the expression of MHCII and CD80,and the secretion of TNF-? and IL-12 p70 significantly in contrast to that of negative control.GNP25 and 27 showed no obvious effect on MHCII and IL-12 p70,however,they induced the significant expression of CD80.Furthermore,GNP27 promoted the secretion of TNF-?.These results are consistent with those in THP1-DualTM cells.It indicated that the QNAR analysis results obtained in THP1-DualTM cells are basically applicable to DCs,and we could modulate the immune response of GNPs through the surface chemistry.This work provides a solid foundation for the systematical research on the immunomodulation of BMDCs by nanoparticles.