Proteomic analysis of differentially expressed proteins in the three developmental stages of Trichinella spiralis

Trichinella spiralis, an intracellular parasitic nematode, can cause severe foodborne zoonosis, trichinellosis. The life cycle of T. spiralis consists of adult (Ad), muscle larvae (ML) and newborn larvae (NBL). The protein profiles in different developmental stages of the parasite remain unknown. In the present study, proteins from lysates of Ad, ML and NBL were identified by isobaric tags for relative and absolute quantitation (iTRAQ). A total of 4691 proteins were identified in all the developmental stages, of which 1067 proteins were differentially expressed. The number of up-regulated proteins in NBL was higher than that of the other two groups. The protein profiles from Ad, ML and NBL were compared in pairs. The identified proteins were involved in various functions of T. spiralis life cycle, including sexual maturity, metabolism, utilization of carbohydrates, lipids and nucleotides, and other crucial developmental processes that occur at distinct stages. Further investigation of the transcriptional levels of major sperm protein, serine protease, zinc finger protein, etc. from the different protein profiles using quantitative RT-PCR showed identical results to the iTRAQ analysis. The differentially expressed proteins that are involved in developmental regulation and host-parasite interactions should be further studied.