Caracterização funcional do fator de transcrição SmZF1 de Schistosoma mansoni por interferência de RNA (RNAi)

Abstract

Schistosomiasis is a disease caused by parasites of Schistosoma genus. This parasitic disease is one of the most prevalent among the neglected tropical diseases affecting over 240 million people worldwide. In Brazil, schistosomiasis is caused by Schistosoma mansoni. S. mansoni is exposed to different environments during its complex life cycle, in which the regulation of gene expression plays a central role in the morphological and physiological changes required for parasite development. The SmZF1 protein, a transcription factor from S. mansoni that contains four C2H2 zinc fingers, represents a potential research target for the understanding of gene expression control associated to the parasite larval development and adult worm reproduction. Herein we performed functional studies through RNA interference (RNAi) in order to investigate whether SmZF1 is involved in the establishment of S. mansoni infection in the mammalian host. Therefore, we induced the silencing of SmZF1 mRNA by soaking schistosomula cultivated in vitro with SmZF1 dsRNA for seven days. We show that SmZF1 transcript levels were effective and specifically reduced by 69% relative to untreated control. Schistosomula growth was slightly affected after two days of treatment with SmZF1 dsRNA. Futhermore, the gene expression of two putative genes targeted by SmZF1, Smp_065180 and Smp_030710 were not significantly affected by SmZF1 silencing. We found that SmZF1 knockdown was transient, because the RNAi induced in schistosomules did not persisted in adult worms derived from mice infected with dsRNA-treated parasites. In addition, parasite and liver egg burden recovered from mice infected with transformed schistosomula compared to control infection was significantly reduced by 72% and 70%, respectively. We observed no changes in histopathological parameters from liver of mice infected with knockdown schistosomula. The results suggest that SmZF1 might play a role during S. mansoni larval development and parasite infection establishment in the mammalian host.