ABSTRACT
This study was designed to obtain recombinant human thioredoxin (rhTXN) by gene cloning and prokaryotic expression, and evaluated its therapeutic effect in the mouse ulcerative colitis (UC) model induced by dextran sulfate sodium (DSS). The human thioredoxin gene TXN was cloned from the cDNA of Jurkat cells. The recombinant expression plasmid pCold TF-rhTXN was constructed by restriction enzyme digestion. After expression in E. coli BL21 (DE3), recombinant human thioredoxin was purified by a nickel column. Intact rhTXN recombinant protein was obtained after removal of the fusion partner-tag by enzyme digestion and the activity of disulfide reductase was detected by the insulin reduction method. The animal experiments in this study were performed in accordance with the ethical guidelines of the Laboratory Animal Welfare Ethical Review Committee of Nanjing University. Experiment ulcerative colitis was induced by providing mice with sterilized drinking water which contained 3% DSS. rhTXN was injected intraperitoneally. The therapeutic effect was studied by weight change, colon length and HE (hematoxylin and eosin) stained sections. In vivo imaging was used to study the targeting of rhTXN to DSS mice. The GSE107499 data set of GEO database was used to screen the hub genes at the lesional sites of UC and study the correlation with TXN. The experimental results showed that rhTXN was successfully expressed and purified with disulfide reductase activity. rhTXN (100 μg·kg-1) had a significant therapeutic effect on maintaining the weight change of mice (P = 0.000 5) and reducing intestinal injury (P < 0.000 1), and had a colon targeting effect on DSS mice. In GSE107499 data set, TXN in inflammatory sites of UC patients was significantly down regulated (P < 0.01) and negatively correlated with hub gene CD40 (P < 0.01) and positively correlated with hub gene fibronectin 1 (FN1) (P < 0.01). In this study, biologically active rhTXN was successfully prepared and proved to have a promising therapeutic effect on the DSS mouse model, and TXN gene was significantly correlated with the UC hub genes CD40 and FN1.