The Effects Of Osmotic Pressure On The Biomechanical Properties And Immune Functions Of Immature Dendritic Cells

Objective This study investigated the effect of osmotic pressure on the biomechanical properties and immune function of imDCs from the perspective of mechanobiology,in order to further understand the immunoregulatory function of imDCs.Methods Monocytes from human peripheral blood were isolated by density gradient centrifugation and induced by recombinant human interleukin-4 and recombinant human granulocyte macrophage colony-stimulating factor to obtain immature dendritic cells(imDCs).imDCs were treated with different osmolalities of 355 mOsm/kg,325 mOsm/kg,295 mOsm/kg,265 mOsm/kg,235 mOsm/kg for 30 min and 1 h.After treated with different osmotic pressures,the cell viability of imDCs was detected using Cell Counting Kit-8(CCK-8).The changes of cell morphology and cytoskeleton structure were observed by inverted microscope and laser confocal scanning microscope,respectively.Cell electrophoresis was applied to detect the changes in cell electrophoresis mobility.DPH incubated with imDCs for half an hour,The membrane fluidity of the cells was detected by fluorescence polarization method.Incubation of imDCs with FITC-labeled dextran,the antigen-phagocytic ability of imDCs was examined by flow cytometry.And the expression changes of immunerelated molecules were detected by real-time fluorescent quantitative PCR(qPCR).Results Both hyperosmosis and hypoosmosis could remodel the cytoskeleton of cells,even induce apoptosis.The cytoskeleton was remodeled.The electrophoresis mobility of the hypoosmosis group was significantly higher than that of the normal osmolarity group,while that of the hyperosmosis group show an opposite tendency(P<0.05).Fluorescence polarization results showed that both hyperosmosis and hypoosmosis could significantly decrease the membrane fluidity of cells(P<0.05).The results of qPCR detection showed that both hyperosmosis and hypoosmosis could significantly increase the expression of CCR7,CD40,CD205,CD11 a,CD11c on the surface of imDCs(P<0.05),and the phagocytic function of imDCs were increased(P<0.05).Conclusion Hypertonic and hypotonic stress can change the cell electrophoresis mobility,membrane fluidity,and the expression of immune-related molecules,which is important for understanding the immune regulation function of DCs.