Studies have shown that IL-10 has therapeutic potential for inflammatory diseases. However, it is challenging to use IL-10 as a therapeutic drug because it also possesses pro-inflammatory functions. To reduce these pro-inflammatory effects of IL-10, we have designed three IL-10 mutants using structure-based computational design technology. We demonstrated that these mutants exhibited significantly lower activity in IL-10-responsive cell lines than wild-type IL-10. Using recombinant adeno-associated virus (rAAV8) vectors expressing wild-type or mutant IL-10 molecules, we performed gene therapy experiments in IL-10 KO mice. The results showed that our vectors mediated high levels of transgene expression. Importantly, IL-10 gene therapy increased body weight gain, reduced colon injury, and prevented the development of inflammatory bowel disease (IBD). Moreover, IL-10 mutant gene therapy elicited significantly lower stimulation of CD8 T and NK cells compared with the wild-type IL-10 group. In summary, our IL-10 mutants provide a protective effect comparable to wild-type IL-10 in the IL-10 KO mouse model, suggesting that they may potentially have reduced pro-inflammatory function. While rigorous investigations of safety and efficacy in different disease models will be required, these results indicate the therapeutic potential of IL-10 mutant gene therapy for inflammatory diseases such as IBD.
Stokes et al. (Mon,) studied this question.