Tissue Transglutaminase-Regulated Transformed Growth Factor-β1 in the Parasite LinksSchistosoma japonicumInfection with Liver Fibrosis
Transforming growth factor (TGF-β1) is among the strongest factors of liver fibrogenesis, but its association withSchistosoma-caused liver fibrosis is controversial. Tissue transglutaminase (tTG) is the principal enzyme controlling TGF-β1 maturation and contributes toSj-infected liver fibrosis. Here we aim to explore the consistency between tTG and TGF-β1 and TGF-β1 source and its correlation with liver fibrosis afterSj-infection. TGF-β1 was upregulated at weeks 6 and 8 upon liver fibrosis induction. During tTG inhibition, TGF-β1 level decreased in sera and liver of infected mice. TGF-β1 showed positive staining in liver containingSjadult worms and eggs. TGF-β1 was also detected inSjadult worm sections, soluble egg antigen andSjadult worm antigen, and adult worms’ culture medium. The TGF-β1 mature peptide cDNA sequence and its extended sequence were amplified through RT-PCR and RACE-PCR using adult worms as template, and sequence is analyzed and loaded to NCBI GenBank (number GQ338152.1). TGF-β1 transcript inSjeggs was higher than in adult worms. InSj-infected liver, transcriptional level of TGF-β1 fromSj, but not mouse liver, correlated with liver fibrosis extent. This study provides evidence that tTG regulates TGF-β1 and illustrates the importance of targeting tTG in treatingSjinfection-induced fibrosis.