Proteomic Analysis Associated with the Immune Response in Hemocytes of Portunus trituberculatus Challenged with Vibrio parahaemolyticus

Vibrio parahaemolyticus belongs to an expanding group of aquatic pathogens that are widely distributed in aquatic environments. This species is a lethal pathogen for a number of economically important marine crabs. However, studies exploring host–vibrio interactions between V. parahaemolyticus and crabs are scarce, and therefore, the underlying molecular mechanisms are unclear. Herein, we performed a comprehensive proteomic analysis to investigate the immune response of Portunus trituberculatus hemocytes to V. parahaemolyticus infection. A total of 4433 proteins were identified using isobaric tags for relative and absolute quantitation (iTRAQ), and 526 differentially expressed proteins (DEPs) were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, with six DEPs further subjected to quantitative real-time PCR. Several identified DEPs were found to be mainly involved in the immune defense of the crustacean, such as a hemocyanin subunit, C-type lectin, α-2-macroglobulin, Cu/Zn-superoxide dismutase, and heat shock protein 70, playing a key role in the response to V. parahaemolyticus infection. Moreover, many immune-related KEGG pathways were markedly altered, such as cell adhesion molecules, complement and coagulation cascades, and phagosomes. Our results provide insights into how V. parahaemolyticus overcomes the innate immunity of P. trituberculatus to induce pathological alterations in affected tissues. We report the first iTRAQ-based proteomic analysis and highlight the key pathways and proteins involved in the host–vibrio interactions between P. trituberculatus and V. parahaemolyticus. These findings should enhance our understanding of the molecular mechanisms underlying such interactions.