Epigenetic Changes Modulate Schistosome Egg Formation and Are a Novel Target for Reducing Transmission of Schistosomiasis

Abstract

Treatment and control of schistosomiasis relies on the only available drug, praziquantel, and the search for alternative chemotherapeutic agents is therefore urgent. Egg production is required for the transmission and immunopathology of schistosomiasis and females of S. mansoni lay 300 eggs daily. A large fraction of the total mRNA in the mature female worm encodes one eggshell protein, Smp14. We report that the nuclear receptors SmRXR1 and SmNR1 regulate Smp14 transcription through the recruitment of two histone acetyltransferases (HATs), SmGCN5 and SmCBP1. The treatment of HEK293 cells with histone deacetylase (HDAC) inhibitors (NaB or TSA) produced an 8-fold activation of the SmRXR1/SmNR1-mediated Smp14 promoter activity. Incubation with synthetic HAT inhibitors, including PU139, significantly impaired the Smp14 promoter activity in these cells. Worm pairs cultivated in the presence of PU139 exhibited limited expression of Smp14 mRNA and protein. ChIP analysis demonstrated chromatin condensation at the Smp14 promoter site in worms treated with PU139. ChIP also revealed the presence of H3K27me3 and the absence of RNA Pol II at the Smp14 promoter region in the PU139-treated worms. Most significantly, the PU139-mediated inhibition of Smp14 expression resulted in a significant number of abnormal eggs as well as defective eggs within the ootype. In addition, scanning electron microscopy revealed structural defects and unformed eggshells, and vitelline cell leakage was apparent. The dsRNAi-targeting of SmGCN5 or SmCBP1 significantly decreased Smp14 transcription and protein synthesis, which compromised the reproductive system of mature female worms, egg-laying and egg morphology. Our data strongly suggest that the inhibition of Smp14 expression targeting SmGCN5 and/or SmCBP1 represents a novel and effective strategy to control S. mansoni egg development.

Tissue Degeneration following Loss of Schistosoma mansoni cbp1 Is Associated with Increased Stem Cell Proliferation and Parasite Death In Vivo

“…In mammals, these proteins serve as transcriptional co-activators that possess histone acetyltransferase (HAT) activity [11]. In schistosomes, cbp1 was previously demonstrated to act as a transcriptional co-activator in vitro [10] and suggested to regulate genes important for schistosome egg production via its HAT activity [12]. Here we show that abrogation of cbp1 function leads to simultaneous increases in cell death and neoblast proliferation.…”

Pharmacological inhibition of lysine-specific demethylase 1 (LSD1) induces global transcriptional deregulation and ultrastructural alterations that impair viability in Schistosoma mansoni

“…For the confocal microscopy analysis, the adult worms were fixed and stained as 329 previously described (34). Confocal scanning laser microscopy was performed on a Zeiss 330 LSM 800 microscope equipped with a 488-nm HE/Ne laser and a 470-nm long-pass filter but 331 without the reflection mode.…”

“…were performed to analyze ultrastructural alterations in the parasites. Adult worms or 335 schistosomula were incubated with 25 µM MC3935 or 0.25% DMSO for 48 or 72h, and 336 fixed, as previously described (34). For SEM analysis, the samples were dehydrated with 337 increasing concentrations of ethanol and then dried with liquid CO2 in a critical-point dryer 338 machine (Leica EM CPD030, Leica Microsystems, Illinois, USA) (35).…”

“…In recent years, targeting the Schistosoma mansoni 99 epigenome has emerged as a new and promising strategy to control schistosomiasis. The 100 study of histone acetylation in S. mansoni biology and the effect of inhibitors of histone 101 deacetylases (HDACs and SIRTs) or histone acetyltransferases (HATs) on parasite 102 development and survival have demonstrated the importance of these enzymes as potential 103 therapeutic targets (8)(9)(10)(11)(12). 104…”

Epigenetics in Schistosomes: What We Know and What We Need Know

“…Sm CBP/p300 was also identified in S. mansoni , and it was expressed during all life cycle stages, interacted functionally with the nuclear receptor SmFtz-F1 and also potentiated the transcriptional activity of this receptor in the CV-1 cell line (Bertin et al, 2006). Knocking down SmGCN5 or SmCBP1 significantly decreased the transcription and protein synthesis of Smp14, an eggshell protein in the mature female worm, damaging the reproductive system of mature female worms, egg-laying and egg morphology (Carneiro et al, 2014). This result suggests that inhibition of Smp14 expression targeting SmGCN5 and/or SmCBP1 represents a novel and effective strategy to control S. mansoni egg development and that HATs can be used as a drug target against schistosomiasis.…”