Knockdown of let-7-5p from Echinococcus multilocularis Inhibited the Peritoneal Macrophages Polarization and Worm Growth in BALB/c Mice
The purpose of this study was to determine the effects of knockdown of Echinococcus multilocularis emu-let-7-5p on mouse peritoneal macrophages polarization and worm growth.A recombinant adeno-associated virus vector expressing emu-let-7-5p sponge sequence of E.multi-locularis was constructed,and its inhibitory effect and specificity were validated in 293T cells.Seventy clean-grade BALB/c mice were injected intravenously(tail vein)with AAV8-si-let-7-5p,AAV8-control,and PBS,respectively.After two weeks,two mice in each group were randomly selected,and the expression of GFP,emu-let-7-5p and its target C/EBP δ in liver were detected by Western blot and qRT-PCR.At 3 months after intraperitoneal inoculation of 1 000 proto-scolexs in each mouse,the transcriptional levels of emu-let-7-5p,C/EBP δ,M1 type(IL-1β,iN-OS and IL-6)and M2 type(Arg-1,IL-4 and IL-10)related molecules in peritoneal macrophages were detected by qRT-PCR,and cysts weight and protoscolexs number of E.multilocularis in each group were analyzed.The results showed that,on the 15th day after injection,AAV8-si-let-7-5p successfully targeted the mouse liver and caused knockdown of emu-let-7-5p and up-regula-tion of C/EBP δ.At 3 months after infection,the expressions of emu-let-7-5p and M2 related molecule(Arg-1)in peritoneal macrophages were significantly down-regulated in AAV8-si-let-7-5p group,while C/EBP δ and M1 related molecules(IL-1β and iNOS)were significantly up-regu-lated.In addition,in AAV8-si-let-7-5p group,the expressions of IL-4 and IL-6 were down-regu-lated,while the expression of IL-10 was up-regulated,and cysts weight and protoscolexs number in AAV8-si-let-7-5p group were significantly lower than those in the control group.The above re-sults suggested that knockdown of emu-let-7-5p in mice infected with E.multilocularis can pro-mote the expression of C/EPB δ,and thus inhibit M2 macrophage polarization and worm growth.