Soluble Expression Of Murine IFN-ε And Its Effects On Postmenopausal Urinary Tract Infection In Mice

The objective of this study was to produce and purify soluble recombinant murine Interferon-epsilon(IFN-ε)in bacterial expression system and verify its biological activity;and to explore the effect of murine IFN-ε in the treatment of murine urinary tract infection during menopause.We subcloned the murine IFN-ε gene into expression vector pET28a-SUMO,which was subsequently transformed into Escherichia coli strain BL21(DE3)together with chaperones plasmid Pg-tf2 containing 3 chaperones(groES、groEL 、 tig).All experimental female mice were castrated and highly pathogenic Escherichia coli was perfused into bladder in order to established a stable animal model of postmenopausal urinary tract infection.The results of ovariectomized female mice were checked by using vaginal smears,vaginal keratinocytic method,and serum estradiol2 level and the result of urinary tract infection were tested by bladder pathological section and germiculture.Murine IFN-ε perfused into bladder after the animal model of postmenopausal urinary tract infection was established.Then we observed the result of bladder pathological section and germiculture,and tested the inflammatory factor IL-5 by ELISA.The experimental results are listed as follows:1、The recombinant murine IFN-ε-SUMO fusion protein was purified using affinity,anion-exchange and gel filtration chromatography,followed by Ulp1 digestion to release the SUMO-tag.SDS-PAGE demonstrated that the molecular weight of the fusion protein was 35KD;the protein of murine IFN-ε was still soluble after SUMO tag removal;peptide fingerprinting spectrometry demonstrated that the expressed product was the authentic murine IFN-ε protein.The murine IFN-ε protein could inbibit the proliferation of He La cel s and induce the expression of anti-viral protein MxA in HeLa cel s.2、Murine IFN-ε could inhibit the UPEC in the urethra of the mice which had postmenopausal urinary tract infection.It could also down-regulated the expression of some inflammatory factors,such as IL-5,and repair the infected bladder tissue.Optimal conditions for soluble expression and purification of recombinant murine IFN-ε have been established in our experiments with results serving as a good starting point for srudy of biological activity.Murine IFN-ε has some therapeutic effect on postmenopausal urinary tract infection in mice.