Discipline: Biological Sciences
Webs Pierre - University of the District of Columbia
Co-Author(s): Michael Smith, Carolyn Cousin, and Matty Knight
Biomphalaria glabrata is the intermediate snail host of the parasitic trematode, Schistosoma mansoni, a causative agent of a devastating tropical disease in the Western Hemisphere, schistosomiasis. These snails are known to display a wide range of susceptibility phenotypes depending on the genetics of both the snail and the invading parasite. Recent studies have shown that by using double stranded RNA (dsRNA) with the non-viral inert cationic delivery agent, polyethyleneimine (PEI), successful gene silencing in the snail host can be achieved. Since high basal levels and early expression of Cathepsin B were found to correlate with resistance to S. mansoni in the resistant BS- 90 snail host, we hypothesized that knock down of the Cathepsin B (Cath B) gene will allow the miracidia to enter the snail, but subsequent development into the sporocytes (mother and daughter) and cercaria stages may not occur. Using the corresponding CathB dsRNA and PEI delivery method in BS-90 resistant snails will suppress the expression of CathB, thereby reducing or preventing the early destruction of the parasite normally seen in these snails. Twelve snails were soaked for 48 hours with dsRNA/ PEI nanoparticle complexes before exposure to the parasite. At 6wk-post-exposure, experimental and control snails were monitored for cercariae shedding. RT- PCR with CathB gene specific primers was used to validate the successful knock down of the CathB gene in dsRNA/PEI transfected snails, done in parallel using control mock myoglobin dsRNA/PEI transfected snails. Change in qualitative expression of CathB was determined relative to the housekeeping actin gene. The BS-90 snails released cercaria 6wk-post-exposure, thereby altering the normally resistant BS-90 snail to exhibit the susceptible phenotype.
Funder Acknowledgement(s): Supported by NSF/HBCU-UP-HRD -(0928444), MARC-(1T34GM087172-01A1)
Faculty Advisor: Carolyn Cousin,