Proteomic deciphering of echinococcosis using laser microdissection coupled to LC-MS/MS analyses and MALDI Imaging

Aim: Echinococcosis is a neglected tropical disease caused by the parasitic tapeworm Echinococcus. Commonly infected animals are dogs and foxes that represent hosts for human infection, after spreading of eggs in food and water. The human manifestation mostly occurs in the liver and the symptoms which are amongst others include abdominal pain and fever, which can be very weak until the cyst by the worm reaches a big size. The treatment generally consist in surgery but this can be impossible if the cysts are presents in multiples sites. In these cases, chemotherapeutic agents or antiparasitic drugs such as albendazole are administered. Finding new biomarkers of different echinococcal species may help to treat patients more effectively. Methods: Sections of livers infected by Echinococcus granulosus were processed using a recently developed method for laser microdissection based microproteomics. The sampling step consisted in isolating the worm itself and his secretions from the cyst and the liver itself. The tissue digests were analyzed by LC-MS/MS using a Nanoacquity UPLC (Waters) coupled to a Q-exactive Orbitrap Mass spectrometer (Thermo) and the data processing was performed using MaxQuant. Subsequent imaging mass spectrometry was also performed. Results: The proteomic analysis was performed using two databank interrogations. Since the proteome of Echinococcus granulosus is poorly described and this worm develops in human, human sequences were also added for identification interrogations. Each of the tissues regions allowed us to retrieve more than 1000 proteins. As expected most of the worm proteins were found in the tissue region occupied by the worm. Interestingly, the three different compartments (liver, echinococcal cyst and the worm) could clearly be distinguished. Conclusion: In the present study we show differences in the protein pattern comparing the worm Echinocuccus, the echinococcal cyst and the surrounding liver tissue by mass spectrometry. Thus, mass spectrometry may serve as diagnostic tool for the identification of an echinococcal infection. Further analyses may allow to distinguish between different species of Echinococcus.