Background
Hepatic schistosomiasis, a chronic liver injury induced by long-term Schistosoma japonicum (S. japonicum) infection, is characterized by egg granulomas and fibrotic pathology. Hepatic progenitor cells (HPCs), which are nearly absent or quiescent in normal liver, play vital roles in chronic and severe liver injury. But their role in the progression of liver injury during infection remains unknown.
Conclusions
Our data uncovered a protective role of HPCs in hepatic schistosomiasis in an IL-33-dependent manner, which might provide a promising progenitor cell therapy for hepatic schistosomiasis.
Methods
In this study, the hepatic egg granulomas, fibrosis and proliferation of HPCs were analyzed in the mice model of S. japonicum infection at different infectious stages. For validating the role of HPCs in hepatic injury, tumor necrosis factor-like-weak inducer of apoptosis (TWEAK) and TWEAK blocking antibody were used to manipulate the proliferation of HPCs in wild-type and IL-33-/- mice infected with S. japonicum.
Results
We found that the proliferation of HPCs was accompanied by inflammatory granulomas and fibrosis formation. HPCs expansion promoted liver regeneration and inhibited inflammatory egg granulomas, as well as the deposition of fibrotic collagen. Interestingly, the expression of IL-33 was negatively associated with HPCs' expansion. There were no obvious differences of liver injury caused by infection between wild-type and IL-33-/- mice with HPCs' expansion. However, liver injury was more attenuated in IL-33-/- mice than wild-type mice when the proliferation of HPCs was inhibited by anti-TWEAK. Conclusions: Our data uncovered a protective role of HPCs in hepatic schistosomiasis in an IL-33-dependent manner, which might provide a promising progenitor cell therapy for hepatic schistosomiasis.