Plasmodium-derived MIF Secretion Pathway And Its Effect On Gene Expression In Host Cell

Malaria is one of the most severe infectious diseases in the world,but the global work on anti-malaria still can't control the disease effectively due to lack of enough knowledge of mechanisms for invasion and malaria parasite escaping from host immune attack.Macrophage migration inhibitory factor(MIF) involve kinds of biological reaction in organ comprehensively,but exact biological functions and mechanism of homologues of MIF in Plasmodium,are still not understood well.In the previous work of our lab,we identified two malaria-derived MIF homologues(PfMIF and PyMIF) from Plasmodiumfalciparum and Plasmodium yoelii respectively.Compared the enzymatic and chemotactic activities between PfMIF and host HuMIF,and detected the PfMIF protein level in serum in vivo and PyMIF protein level in serum in vivo of infectious mouse.In this experiment,we researched plasmodium-derived macrophage migration inhibitory factor(MIF) secretion pathway and its effect on signal pathway in macrophage of mouse.The results showed that,Glyburide inhibited secretion of PfMIF in mammalian cell.In addition,which indicated that PfMIF secretion was carried out by ABCA1 transporter and correspond with HuMIF.We attempted the inhibitors in plasmodium infectious RBC(PRBC),result showed that the higher concentration of inhibitor the lower level of PfMIF in a cell of medium,which indicated that PfMIF secretion in PRBC was carried out by endocytosis.Due to the toxicity of inhibitors,we still can't ascertain the secretion pathway,we need further research into the mechanism of secretion.In Part 2,we compared the regulation difference of signal pathway in host mouse macrophage between PyMIF and MuMIF by real-time PCR chip,extracted the genes which varied significantly on transcriptional level,then repeat the experiment by further checking transcriptional level of the interesting genes with RT-PCR.We found that both PyMIF and MuMIF could significantly up-regulate and down-regulate transcriptional level of several same signal pathway-related genes;compared by MuMIF,PyMIF could significantly up-regulate and down-regulate transcriptional level of several genes.In addition,both PyMIF and MuMIF couldn't significantly change transcriptional level of main Jak-STAT pathway-related genes.The result of RT-PCR is similar with result of real-time PCR chip.The result of Part 2 indicated that, PyMIF acted on the macrophages of mouse to maintain the activity of the target cells by up-regulating oncogenes along the down stream of the signal pathways,and regulated host cell apoptosis with complex effects.In conclusion,these two parts of experiment shows malaria-derived MIF's secretion pathway,and the role of regulating cytokine and signal pathway-related genes in host cell,which is helpful for further understandingt the biological function of Plasmodium.