The Studies On The Effect Of VEGF On The Biophysical Characteristics And Motility Of Human Mature Dendritic Cells As Well As Underlying Molecular Mechanism

Objective：Dendritic cells (DCs), the most potent antigen-presentingcells as now known, can effectively uptake, process and present antigens, and play acentral role in initiation, regulation and maintain immune responses. Recently, theanti-tumor character of DC is globally research hot spot. The tumormicroenvironment is the important battleground of tumor cells proliferation and DCsperforming immune function. The previous studies of our group established thecomprehensive effects of tumor microenvironment-derived suppressive cytokinesincluding vascular endothelial growth factor (VEGF), transformed growth factor-β1(TGF-β1) and interleukin-10(IL-10) on DCs functions.But the action of singlecytokine is still elusive. This study will explore the effects of VEGF on biophyscialcharacteristics of mDCs from biophysical and molecular biology interdisciplinaryperspective in order to understand the biological behavior of DCs and immune escapemechanism of tumor.Methods：mDCs were treated by different concentrations (0,10,30,50,70ng/ml respectively) of VEGF and cultured in different conditionedmediums. The electrophoretic mobilities, osmotic fragilities, membrane viscolasticproperties, the ability of transendothelial migration of mDCs and cytoskeleton system(F-actin), the expression level of F-actin and apoptosis were investigated. In thesecond part of my study, The mDCs were treated by50ng/ml VEGF, gene expressionprofiles, the level of some genes, the secondary structure of proteins and theexpression level of some cytoskeleton binding protein were investigated.Results：Theresults showed that the electrophoretic mobility of mDCs was decreased significantlyat30ng/ml (P<0.05) and50ng/ml (P<0.01); the osmotic fragilities of mDCs was reduced at50ng/ml (P<0.01); the membrane protrusive activities of cells wereseverely decreased at30,50,70ng/ml; Transmigration capability of mDCs wasimpaired at50ng/ml (P<0.05); the cytoskeletons (F-actin) of cells were dysfunctionand their expression levels were increased at50ng/ml (P<0.01) and decreased at30ng/ml and70ng/ml (P<0.01). However, there was no significant difference inapoptosis rate；microarray showed that2445genes were up-regulated and2417geneswere down-regulated, which involved in the immune response, transendothelialmigration,adhesion and regulation of actin cytoskeleton; TR-PCR show genes ofLIMK1，ARPC5, ITGB2, GSN, PDGFR, HSPB1, SDCBP were down-regulated whilegenes of PIP5K1B, EIF2S3, PKC were up-regulated；the co-location of cofilin andp-cofilin in mDC,but the mean fluorescence intensity was down-regulated at50ng/mlVEGF (P<0.01); the result of fourier transform infrared spectrum showed that therewas slight decreased in A1545at50ng/ml; the expression levels of p-cofiln wereup-regulated, the expression levels of cofilin and p-cofilin（P<0.05）as well as LIMK1（P<0.01） and Fascin-1,profilin were up-regulated and down-regulatedrespectivelyand.Conclusions：The biophysical characteristics of mDCs were affectedby VEGF in concentration-depend fashion. Moreover, it is suggested that VEGFaffected the biophysical characteristics and immunology functions of mDCs by theRhoA-Cofilin1pathway. It’s significant for understanding the biological behaviorsand immune escape mechanism.