Integrative Omics Analysis Reveals the Immunomodulatory Effects of the Parasitic Dinoflagellate Hematodinium on Crustacean Immunity

Abstract

Parasitic dinoflagellates in genus Hematodinium have caused substantial economic losses to multiple commercially valuable marine crustaceans around the world. In the present study, comprehensive omics approaches (miRNA transcriptomics, iTRAQ-based proteomics) were applied to investigate the host-parasite interaction between hemocytes from Portunus trituberculatus and Hematodinium perezi. The parasitic dinoflagellate remodeled the miRNome and proteome of hemocytes from challenged hosts, modulated the host immune response at both post-transcriptional and translational levels and caused post-transcriptional regulation to the host immune response. Multiple important cellular and humoral immune-related pathways (ex. Apoptosis, Endocytosis, ECM-receptor interaction, proPO activation pathway, Toll- like signaling pathway, Jak-STAT signaling pathway) were significantly affected by Hematodinium parasites. Through modulation of the host miRNome, the host immune responses of nodulation, proPO activation and antimicrobial peptides were significantly suppressed. Cellular homeostasis was imbalanced via post-transcriptional dysregulation of the phagosome, peroxisome, and lysosome pathways. Cellular structure and communication was seriously impacted by post-transcriptional downregulation of ECM-receptor interaction and focal adhesion pathways. Author summaryThe parasitic dinoflagellate Hematodinium infects many economically important marine crustaceans. Recent efforts to better understand the life cycle and biology of the parasite have improved our understanding of the disease ecology. However, studies on the host-parasite interaction, especially how Hematodinium parasites evade the host immune response are lacking. To address this shortfall, we used miRNA transcriptomics and iTRAQ-based proteomic approaches to explore the immune responses of Portunus trituberculatus when challenged with Hematodinium perezi. Striking changes in the miRNome and proteome of hemocytes were observed, and the parasite exhibited multifaceted immunomodulatory effects and potential immune-evasion mechanisms in this crustacean host.