Abstract
BACKGROUND: Nuclear receptors (NRs) are vital for regulating gene expression in organisms. Hepatocyte nuclear factor 4 (HNF4), a class of NRs, participates in blood feeding and intestinal maintenance in schistosomes. However, there are limited researches on the molecular and functional characterization of HNF4 in Schistosoma japonicum (S. japonicum). METHODS: Highly specific polyclonal antibodies were generated to analyze the expression and tissue localization of S. japonicum HNF4 (SjHNF4). The potential biological functions of SjHNF4 were characterized by transcriptome and pull-down analyses. Subsequently, enrichment analysis was performed to identify the specific signaling pathways linked to SjHNF4. RESULTS: The SjHNF4 protein was expressed heterologously and purified successfully. High purity and high potency polyclonal antibodies were further prepared. The expression of SjHNF4 was higher in female compared to male worms at both transcriptional and protein levels. Female worms expressed SjHNF4 in their perithecium, reproductive system, and certain parts of the intestinal tissues. SjHNF4 was also detected in the perithecium of male worms, as well as in the head, body of cercariae, and eggs. Furthermore, our findings highlighted the potential role of SjHNF4 in blood feeding and its interaction with crucial pathways such as glucose metabolism, lipid metabolism, and nucleotide metabolism. CONCLUSIONS: This study shed light on the localization of SjHNF4 in different life stages of S. japonicum, particularly associated with the female schistosomes. A strong correlation was observed between SjHNF4 and essential metabolic pathways. These findings laid a solid groundwork for the research on the relationship between NRs and schistosomes.