Screening Of Proteins Secreted By Mycobacterium Marinum And Their Effects On The Function Of Macrophages

Mycobacterium tuberculosis is able to evade the immune defense of host cells and remain dormant in the host cells for a long time,thus making tuberculosis difficult to be detected and treated.The secretory proteins of Mycobacterium tuberculosis,as important media for the interaction with host cells,play a significant role in the infection,replication,survival,and latency of Mycobacterium tuberculosis.In order to clarify the pathogenic mechanism and immune evasion mechanism of Mycobacterium tuberculosis,the secretory proteins were screened from the model organism Mycobacterium marinum,and studied of their function on affecting the immune response of macrophages.The main results are as follows:?1?By detecting the supernatant filtrate proteins with the method of quantification of proteomics,356 proteins were found to respond to hydrogen peroxide stress,821 proteins were in response to iron deficiency stress,which 201 proteins respond to both hydrogen peroxide stress and iron deficiency stress;?2?By analyzing the results of proteomic assays,204 proteins were proved to be secretory-associated proteins.In them,PE/PPE family proteins and membrane proteins/transmembrane proteins accounted for the majority,about 60%;?3?10 secretory proteins with maximum expressed difference were conducted functional studies,and we found that MMAR₀071 can stimulate the transcription of TNF-? in macrophages while inhibiting the transcription of IL-1?,which as a transcriptional regulator may involve in the regulation of cellular inflammatory response signaling pathways;what's more,MMAR₁515?universal stress protein?and MMAR₂272?resuscitation-promoting factor?have high cytotoxicity;MMAR₂272 and MMAR₂882?MCE-family protein Mce3A?can suppress the increase of ROS level in macrophages and promote the survival of Mycobacterium marinum in macrophages.In summary,MMAR₀071,MMAR₁515,MMAR₂272 and MMAR₂882,the proteins with maximum expressed difference,play significant roles in affecting the function of macrophage.These secretory proteins might be the important factors on Mycobacterium tuberculosis invading host cells.Therefore,the results of this study provide a powerful theoretical basis for the pathogenic mechanism and immune evasion mechanism of Mycobacterium tuberculosis.