Research On The Chlamydial Protein PGP3 And Middle Fragment Blocking The Progression Of The Psoriasis-like Lesion In Mice Model

[Objective] To study a new pathway to block the progression of the IMQ-induced psoriasis-like lesion in mice through pGP3 and it’s middle fragment binding with LL-37 and to decrease the expression of IL-17,IL-22 and IFN-γ in skin lesions.[Methods] To detect GST fusion proteins containing either the full-length pGP3,the pGP3 N-terminal fragment(pGP3n),the middle fragment(pGP3m),or the C-terminal fragment(pGP3c)could precipitated the GST for detection of LL-37 in the pellet fraction using Western blotting.The inhibitory effect of pGP3 and its M-segment on IMQ-induced psoriasis-like dermatitis and its effect on the level of IL-17,IL-22 and IFN-γ in lesions were studied by animal experiments.We were randomly divided Forty-eight BALB/c female mice weighing 18-20 g and 6-8 weeks old into 6 groups,Control group,IMQ group,Ext-pGP3 intervention group,Inj-pGP3 intervention group,and Ext-pGP3 M intervention group,Inj-pGP3 M intervention group.In addition to the normal mice,each group was regularly applied IMQ in the morning.Except for normal group and IMQ group,protein intervention was regularly and quantitatively used in each group every evening.During 7 days of continuous intervention,the changes of the skin lesions of mice model were observed and photographed regularly every day.According to the PASI scoring standard,the severity of the lesions in mice was scored every day.The right ear of IMQ group and pGP3,pGP3 M group were modeled by IMQ and coated with corresponding protein,and the ear thickness of mice was measured daily.On the 8th day after the protein intervention,the mice were killed and some of the tissues were made into paraffin sections,the pathological manifestations were evaluated by HE staining,and the level of IL-17,IL-22,IFN-γmRNA was detected by RT-PCR in the other part of the tissues.Finally,all the data were collected and the effects of different intervention methods on psoriasis lesions were analyzed and compared.[Results] There were typical psoriatic lesions and pathological changes in all IMQ models mice.Compared with the IMQ group,four protein intervention groups were more obvious in the lesions severity and the pathological performance,the decrease of PASI score.The lesions of the protein intervention groups began to decline on the5 th day,yet the IMQ group were still developed to the 7th day.The thicken speed of the ears tissue in Ext-pGP3 and Ext-pG3 M was slower than that of the IMQ group,and there was no significant difference between the two protein groups.However,data of the four protein intervention groups indicate that the improvement of the lesions severity and the PASI score of the Ext-pGP3 group were recoverd slower than that of the other three groups.The levels of IL-17,IL-22 and IFN-γ in the lesion tissue of four protein groups were significantly lower than that of the IMQ group(P<0.05).However,the expression of three inflammatory factors of Ext-pGP3 group was significantly lower than that of Inj-pGP3 group(P<0.05).There was no significant difference in cytokines lever between Inj-pGP3 M group and Ext-pG3 M group(P> 0.05).[Conclusion] Chlamydia protein pGP3 and it’s middle fragment can effectively inhibit the IMQ-induced psoriatic lesions in the mice model,and restrain the expression of IL-17,IL-22 and IFN-γ in impaired skin tissue.