Expression, purification, and characterization of scar tissue neovasculature endothelial cell-targeted rhIL10 in Escherichia coli.

Interleukin 10 (IL10) plays a pivotal role in the anti-inflammatory response and immunosuppressive reactions. It has also been identified as a new promising therapy for scar formation. Treatment of scars with IL10 has significant effects, but there are some shortcomings, including poor tissue-binding specificity and low effectiveness. RGD peptide has been demonstrated to bind specifically to αvß3 integrin on neovasculature endothelial cells, and the excess production of neovasculature is crucial to scar formation. To increase efficacy against scar formation and to decrease the side effects on normal tissues, a novel hybrid protein combining human IL10 with RGD was designed. The DNA sequence encoding the recombinant fusion protein IL10-RGD (rhIL10-RGD) was subcloned into a pET22b (+) vector for protein expression in E. coli strain BL21 (DE3). SDS-PAGE analysis displayed an induced expression product band at a molecular weight of 19.3 kDa, which constituted 30 % of the total bacterial protein. We developed a procedure to purify rhIL10-RGD from inclusion bodies and then renatured the protein using dialysis against urea with a step-down concentration procedure. Hypertrophic scar fibroblasts (HSFs) were treated with rhIL10-RGD, and the fibrosis-related protein levels were assessed by Western blotting. The results indicated that rhIL10-RGD can downregulate the expression levels of Col1 and α-SMA in HSFs and suppress tube formation of HUVECs. These results indicate that rhIL10-RGD has anti-fibrosis effects and can potentially be used to treat the neovasculature in scar formation and improve the abnormal deposition of the extracellular matrix (ECM). Thus, rhIL10-RGD may be a more effective candidate for scar-improvement and anti-fibrosis therapy.