Infection with Schistosoma causes aberrant expression of host microRNAs (miRNAs), and normalizing the levels of dysregulated miRNAs can attenuate pathology. Here, we show that the host miRNA, miR-96, is markedly upregulated during the progression of hepatic schistosomiasis. We demonstrate that elevation of miR-96 induces hepatic fibrosis in infected mice by suppressing the expression of its target gene, Smad7. We show that infection with Schistosoma induces the expression of transforming growth factor beta1 (TGF-beta1), which in turn upregulates the expression of miR-96 through SMAD2/3-DROSHA-mediated post-transcriptional regulation. Furthermore, inhibition of miR-96 with recombinant adeno-associated virus 8 (rAAV8)-mediated delivery of Tough Decoy RNAs in mice attenuated hepatic fibrosis and prevented lethality following schistosome infection. Taken together, our data highlight the potential for rAAV8-mediated inhibition of miR-96 as a therapeutic strategy to treat hepatic schistosomiasis.

Schistosomiasis is a serious parasitic disease in humans, which can lead to liver fibrosis and death. Accumulating evidence indicated that targeting the deregulated microRNAs (miRNAs) could mitigate disease outcomes. Here, we showed that progressive hepatic schistosomiasis caused elevation of miR-21 and efficient and sustained inhibition of miR-21 by using highly hepatic tropic adeno-associated virus serotype 8 (rAAV8), which protected mice against lethal schistosome infection through attenuation of hepatic fibrosis (HF). We demonstrated an additive role of interleukin (IL)-13 and transforming growth factor beta 1 (TGF-beta1) in up-regulating miR-21 expression in hepatic stellate cells (HSCs) by activation of mothers against decapentaplegic (SMAD) proteins. Furthermore, down-regulation of miR-21 in HSCs reversed HF by enhancing SMAD7 expression, thus repressing TGF-beta1/Smad and IL-13/Smad pathways. CONCLUSION: This study suggests the mechanism of IL-13-mediated schistosomiasis HF by up-regulation of miR-21 and highlights the potential of rAAV8-mediated miR-21 inhibition as a therapeutic intervention for hepatic fibrotic diseases, such as schistosomiasis.