The Differentiation Of Macrophages Derived From THP‐1and The Role Of CD137/CD137L In This Process

Background：The heterogeneity of macrophages and their diverse roles in tissue injury and remodeling have been studied by scholars in the past decades. The classically activated macrophages（M1） cause inflammation and mediate tissue destruction when contributing to the clearance of pathogens and dying cells.The nonclassically activated macrophages（M2） have protective roles in inflammation and tissue injury. Monocytes can differentiate into M1or M2，depending on different microenvironment stimulis. Phenotype switch can also occur between M1and M2under certain circumstances. There were a few researchs of treating diseases through induction of different phenotypes of macrophages. The reverse signal induced by CD137/CD137L modulate cellular responses in macrophages，it need to be further studied whether or not the reverse signal can influence the phenotype of macrophages.Objectives：To analyse the biomarkers of different phenotypes of macrophages derived from THP‐1and establish the differential system of THP‐1originated macrophages for the further experiment in vivo.To investigate the influence of anti‐human CD137L antibody（1F1） on the differentiation of macrophages derived from THP‐1.Methods：In the process of differentiation of THP‐1cells by PMA，different stimulis were added to the cells: LPS+IFN‐γ,IL‐4and1F1.The cells and supernatant were collected after a48hours’ culture and proceed for further studies：RT‐PCR and flow cytometry were used for detections of iNOS，arginase‐1and CD206，supernatant was analyzed for IL‐6，IL‐10and TNF‐α by ELISA. Control group and mouse IgG group were also tested.Results：1.In the process of differentiation of THP‐1cells to macrophages,iNOS，IL‐6and TNF‐α were upregulated when stimulated with LPS+IFN‐γ(P<0.05), but downregulated when stimulated with IL‐4(P<0.05),IL‐10was elevated in the presence of IL‐4(P<0.05)；2.CD137L was elevated when THP‐1cells had been differentiated into macrophages,the iNOS mRNA of macrophages derived from THP‐1was upregulated in response to1F1(P<0.05)，but the protein expressions of iNOS，IL‐6，TNF‐α and IL‐10were not influenced；3.Arginase‐1and CD206were not detected in our experiment.Conclusions：1.THP‐1cells polarized to M1in the presence of LPS+IFN‐γ and polarized to M2when stimulated with IL‐4in the process of differentiation；2.CD137L expression was elevated in the process of differentiation of THP‐1cells when treated by PMA.INOS mRNA was upregulated when the cells were treated with1F1，but the protein expressions of iNOS，IL‐6，TNF‐α and IL‐10were not altered，the phenotype of macrophages was probably not influenced by1F1in this experimental model；3.Arginase‐1and CD206were not applicable to be used as markers of M2macrophages derived from THP‐1.