Objective: Investigation of the abundance of proteins secreted by Fasciola hepatica, which is exposed to environmental change after it is removed from the main host, with an advanced proteomic approach.
Methods: Adult Fasciola hepatica parasites, obtained from the main host, were directly placed in phosphate-buffered saline (PBS, at room temperature) and incubated at 37°C for 2 hours (after arrival at the Institute within 1 hour). After this, without applying extra procedures, such as washing the parasites, secreted parasite proteins in PBS were investigated using an advanced proteomic method [a mass spectrometry system with electrospray ionization and quadrupole time-of-flight source coupled to ultra performance liquid chromatography, nano UPLC-ESI-QTOF-MS] with a reviewed F. hepatica protein database (Universal Protein Resource; UniProt) and data-independent acquisition method.
Results: With the proteomic analysis of the PBS, after incubation with the parasites, cathepsin L protease 1, fatty acid-binding protein 1 and 2, thioredoxin peroxidase (TPx), and kunitz-type proteinase inhibitor were identified. The abundance of Fasciola hepatica TPx was approximately 2-6 times higher than that of the other proteins identified in this study (p<0.01).
Conclusion: The stress on the parasite stem from environmental change could be associated with the stimulation of the secretion of TPx. The application of advanced proteomic approaches could provide useful data in the development of effective protective methods against the parasite.