The Effects Of A Traditional Chinese Monomer On Differentiation, Development And Function Of Dendritic Cells And Its Mechanisms

Immunosuppressive agents are a class of new pharmaceutical category developed in cancer chemotherapy, organ transplantation, the immune pathology and clinical immunology. They can inhibit the abnormal immune response, and are widely used in organ transplantation and autoimmune diseases. These drugs have experienced nearly a century of development and many of them have been used in clinical which achieved tremendous economic and social benefits. So it is very important to find new immunosuppressive agents with light side effects .Most of traditional Chinese medicine have potent activity to modulate immune function which contains a lot of monomers with clear pharmacological effects. During past years, thousands of monomers were isolated from Chinese medicine by Professor Weidong Zhang's group in our university. We are very interested in one of the monomers named MD3 which showed inhibitory activity on dendritic cells(DCs). DCs are most important antigen presenting cells. In recent years, more and more studies found that the functions of immunosuppressive drugs are related to DCs. In present study, the effects of the traditional Chinese monomer MD3 on differentiation, development and function of DCs are investigated and its mechanisms are explored.Part I Influence of Chinese medicine monomer MD3 on differentiation and development of dendritic cellsIn order to analyze the influence of Chinese medicine monomer MD3 on differentiation and development of DCs, we isolated mouse bone marrow cells and cultured them with IL-4 and GM-CSF, then treated with MD3 in different concentrations (0,0.4,4,20,40,80μmol / ml) at day 3. After co-culture for 72 hours, we found that MD3 did not significantly affect the proliferation of DCs in the 0-0.4μmol/ml concentration range under the microscope and the cell number, cell colonies showed no significant differences in these groups. In the 20-80μmol/ml concentration, the cell number and colonies decreased significantly and the apoptosis was induced in those cells.To observe the purity of DCs treated with MD3, we labeled DCs with CD11c, and labeled with 7-AAD to remove dead cells. The results showed that in pharmacological concentration range, MD3 does not affect the differentiation of DCs. At the same time, we observed changes of phenotypes of DCs treated with MD3. The results showed that MD3 had no influence on the phenotypes of DCs.In summary, the results indicated that MD3 showed no effect on differentiation and development of DCs. However, apoptosis could be induced by above pharmacological concentrations, indicated that the structure of the monomer may also need to be further modified to reduce its toxicity.part II Influence of Chinese medicine monomer MD3 on functions of dendritic cellsPhagocytosis, cytokine secretion, migration and antigen processing and presenting function are the primary functions of DCs. In this part, we investigated whether the functions of DCs could be regulated by MD3. We found that MD3 showed no significant effect on phagocytic capacity of immature DCs . We also detected the phenotypes of mature DCs treated with MD3. The results showed that MD3 also had no significant effect on phenotypes of mature DCs. The cytokines secreted by DCs stimulated with LPS after pre-treatment with MD3 were also detected by ELISA. The results showed that the DCs secreted high levels of IL-10 and the levels of TNF-αand IL-12P70 did not change significantly. Migration of DCs in vivo also play an important role on biological function of DCs. We found that MD3 could inhibit the ability of migration of immature DCs to MIp-1αchemokine in vitro, while did not affect the capacity of migration of mature DCs to MIp-3β. The expression of chemokine receptors were detected and the results showed that MD3 inhibited the expression of some chemokine receptors in immature DCs. In addition, we also found that the stimulatory capacity of DCs on proliferation of allogeneic T lymphocytes and OVA specific T lymphocytes was inhibited by MD3.In conclusion, this study showed that Chinese medicine monomer MD3 had no significant influence on differentiation and development of DCs, but could significantly inhibit the migration ability of immature DCs and promote IL-10 secretion by mature DCs. The regulatory activities of MD3 on DCs in vitro indicate that MD3 might be a potent immunosuppressive agent with good prospects for applications.