Proteomic analysis of hemolymph from poly(I:C)-stimulated Crassostrea gigas

Comparative Transcriptomic Analyses Revealed the Effects of Poly (I:C) on the Liver and Spleen of Argyrosomus japonicus

Poly (I:C) can work as an immunostimulant and a viral vaccine; however, its functional mechanism in aquatic animals needs to be further investigated. In this study, comparative transcriptomic analyses were performed to investigate the effects of poly (I:C) on Argyrosomus japonicus at 12 h and 48 h postinjection. A total of 194 and 294 differentially expressed genes were obtained in the liver and spleen, respectively. At 12 h, poly (I:C) injection could significantly influence the function of the metabolism-related pathways and immune-related pathways in the liver through the upregulation of the genes GST, LPIN, FOXO1, CYP24A1, ECM1, and SGK1, and the downregulation of the genes IL-1β, CXC19, TNFAIP3, and IRF1. At 48 h, poly (I:C) could enhance the liver energy metabolism by upregulating the genes TXNRD and ECM1, while it also induced some injury in the cells with the downregulation of the genes HBA and CYP24A1. In the spleen, poly (I:C) could regulate the fish immunity and inflammatory response by upregulating the genes DDIT4, C3, EFNA, and MNK, and by downregulating the genes ABCA1, SORT1, TNF, TLR2, IL8, and MHCII at 12 h, and at 48 h, the poly (I:C) had a similar influence as that in the liver. Intersection analyses demonstrated that CYP24A1 and ECM1 were the main functional genes that contributed to the health of the liver. Ten and four genes participated in maintaining the health of the two tissues after 12 h and 48 h, respectively. In summary, our results provided a new insight into ploy (I:C) application in A. japonicus, and it also helped us to better understand the fish response mechanism to the viral vaccine injection.

Hemolymph proteins: An overview across marine arthropods and molluscs

In this compilation we collect information about the main protein components in hemolymph and stress the continued interest in their study. The reasons for such an attention span several areas of biological, veterinarian and medical applications: from the notions for better dealing with the species - belonging to phylum Arthropoda, subphylum Crustacea, and to phylum Mollusca - of economic interest, to the development of 'marine drugs' from the peptides that, in invertebrates, act as antimicrobial, antifungal, antiprotozoal, and/or antiviral agents. Overall, the topic most often on focus is that of innate immunity operated by classes of pattern-recognition proteins. SIGNIFICANCE: The immune response in invertebrates relies on innate rather than on adaptive/acquired effectors. At a difference from the soluble and membrane-bound immunoglobulins and receptors in vertebrates, the antimicrobial, antifungal, antiprotozoal and/or antiviral agents in invertebrates interact with non-self material by targeting some common (rather than some highly specific) structural motifs. Developing this paradigm into (semi) synthetic pharmaceuticals, possibly optimized through the modeling opportunities offered by computational biochemistry, is one of the lessons today's science may learn from the study of marine invertebrates, and specifically of the proteins and peptides in their hemolymph.

The primitive interferon-like system and its antiviral function in molluscs

The phylum mollusca is a very important group in the animal kingdom for the large number and diversified species. Recently, interest in molluscan immunity has increased due to their phylogenetic position and importance in worldwide aquaculture and aquatic environment. As the main aquaculture animal, most molluscs live in the water environment and they have to cope with many pathogen challenges, in which virus is one of the primary causes for the mass mortality. In vertebrates, interferon (IFN) system is generally recognized as the first line of defence against viral infection, while the antiviral mechanisms in molluscs remain to be clearly illuminated. Recently, some IFN-like proteins and IFN-related components have been characterized from molluscs, such as pattern recognition receptors (PRRs), interferon regulatory factors (IRFs), IFN-like receptors, JAK/STAT and IFN-stimulated genes (ISGs), which reinforce the existence of IFN-like system in molluscs. This system can be activated by virus or poly (I:C) challenges and further regulate the antiviral response of haemocytes in molluscs. This review summarizes the research progresses of IFN-like system in molluscs with the emphases on the uniformity and heterogeneity of IFN-like system of molluscs compared to that of other animals, which will be helpful for elucidating the antiviral modulation in molluscs and understanding the origin and evolution of IFN system.

Identification of immune-related proteins of Dreissena polymorpha hemocytes and plasma involved in host-microbe interactions by differential proteomics

Biological responses of zebra mussel Dreissena polymorpha are investigated to assess the impact of contaminants on aquatic organisms and ecosystems. In addition to concentrate chemical contaminants in their tissues, zebra mussels accumulate several microorganisms such as viruses, protozoa and bacteria. In order to understand the molecular mechanisms involved in the defence against microorganisms this study aims at identifying immune proteins from D. polymorpha hemolymph involved in defence against protozoa and viruses. For this purpose, hemolymph were exposed ex vivo to Cryptosporidium parvum and RNA poly I:C. Differential proteomics on both hemocytes and plasma revealed immune proteins modulated under exposures. Different patterns of response were observed after C. parvum and RNA poly I:C exposures. The number of modulated proteins per hemolymphatic compartments suggest that C. parvum is managed in cells while RNA poly I:C is managed in plasma after 4 h exposure. BLAST annotation and GO terms enrichment analysis revealed further characteristics of immune mechanisms. Results showed that many proteins involved in the recognition and destruction of microorganisms were modulated in both exposure conditions, while proteins related to phagocytosis and apoptosis were exclusively modulated by C. parvum. This differential proteomic analysis highlights in zebra mussels modulated proteins involved in the response to microorganisms, which reflect a broad range of immune mechanisms such as recognition, internalization and destruction of microorganisms. This study paves the way for the identification of new markers of immune processes that can be used to assess the impact of both chemical and biological contaminations on the health status of aquatic organisms.

Proteomic profile of Ostrea edulis haemolymph in response to bonamiosis and identification of candidate proteins as resistance markers

European flat oyster Ostrea edulis populations have suffered extensive mortalities caused by bonamiosis. The protozoan parasite Bonamia ostreae is largely responsible for this disease in Europe, while its congener B. exitiosa has been detected more recently in various European countries. Both of these intracellular parasites are able to survive and proliferate within haemocytes, the main cellular effectors of the immune system in molluscs. Two-dimensional electrophoresis was used to compare the haemolymph protein profile between Bonamia spp.-infected and non-infected oysters within 3 different stocks, a Galician stock of oysters selected for resistance against bonamiosis, a non-selected Galician stock and a selected Irish stock. Thirty-four proteins with a presumably relevant role in the oyster-Bonamia spp. interaction were identified; they were involved in major metabolic pathways, such as energy production, respiratory chain, oxidative stress, signal transduction, transcription, translation, protein degradation and cell defence. Furthermore, the haemolymph proteomic profiles of the non-infected oysters of the 2 Galician stocks were compared. As a result, 7 proteins representative of the non-infected Galician oysters selected for resistance against bonamiosis were identified; these 7 proteins could be considered as candidate markers of resistance to bonamiosis, which should be further assessed.

Comparative proteomic analysis of hepatopancreas in Macrobrachium rosenbergii responded to Poly (I:C)

Gel-enhanced liquid chromatography coupled with tandem mass spectrometry (GeLC-MS/MS) was used to analyze the proteome of Macrobrachium rosenbergii hepatopancreas responded to Poly (I:C). GeLC-MS/MS analysis identified 515 differentially-expressed proteins with ≥1.5 and ≤ -0.5 log₂ fold change. Of these, 195 differentially-expressed proteins were significantly matched to known proteins in the database, of which 102 proteins were up-regulated and 93 proteins were down-regulated. These proteins were classified into 21 categories, i.e. metabolic process, oxidative stress response, signaling, transcription, translation, cell cycle, transport, etc. Several immune factors were up-regulated upon Poly (I:C) injection. Protein-protein interaction network analysis of these immune factors identified three major protein clusters including RNAi, stress responses, and Toll pathway-proPO system, implying that Poly (I:C) activates immune responses in prawn through several mechanisms.

Genome-wide gene expression analysis in the amphioxus, Branchiostoma belcheri after poly (I: C) challenge using strand-specific RNA-seq

The gene expression associated with immune response to bacteria/bacterial mimic has been extensively analyzed in amphioxus, but remains largely unknown about how gene are involved in the immune response to viral invasion at expression level. Here, we analyze the rRNA-depleted transcriptomes of Branchiostoma belcheri using strand-specific RNA-seq in response to the viral mimic, poly (I:C) (pIC). A total of 5,317 differentially expressed genes were detected at treatment group by comparing with control. The gene with the most significant expression changes (top 15) after pIC challenge and 7 immune-related categories involving 58 differently expressed genes were scrutinized. By functional enrichment analysis of differently expressed genes, gene ontology terms involving response to stress and stimulus, apoptosis, catabolic and metabolic processes and enzyme activity were overrepresented, and several pathways related to immune signaling, immune response, cancer, apoptosis, viral disease, metabolism were activated after pIC injection. A positive correlation between the qRT-PCR and strand-specific RNA-seq data confirmed the accuracy of the RNA-seq results. Additionally, the expression of genes encoding NLRC5, CASP1, CASP6, CYP450, CAT, and MDA5 were induced in B. belcheri under pIC challenge. Our experiments provide insight into the immune response of amphioxus to pIC and valuable gene expression information for studying the evolution of antiviral immunity in vertebrates.

Primed for success: Oyster parents treated with poly(I:C) produce offspring with enhanced protection against Ostreid herpesvirus type I infection

The Pacific oyster (Crassostrea gigas) is farmed globally. Ostreid herpesvirus (OsHV-1) causes severe mortalities of farmed C. gigas. Management of OsHV-1 has proven difficult. Oysters treated with poly(I:C) exhibit enhanced protection (EP) against OsHV-1. This chemical treatment is highly effective, but it is not feasible to treat every oyster on a farm. To circumvent this practical limitation, previous studies on arthropods have suggested that EP can be transferred from parents to their offspring (trans-generational EP, TGEP). This suggests that the treatment of relatively few parents could be used to produce large numbers of offspring with TGEP. Here, we investigated TGEP in oysters to test whether it might be used as a cost effective management tool to control OsHV-1. We found that offspring (D-veliger larvae) produced from poly(I:C)-treated parents had double the chance of surviving exposure to OsHV-1 compared to controls. Furthermore, the larvae of poly(I:C)-treated parents contained elevated levels of mRNA encoding a key transcription factor that regulates antiviral immunity (IRF2). Poly(I:C) treatment had no effect on the survival of oyster parents. Hence, the enhanced immunity of their offspring could not be explained by genetic selection, and instead may reflect epigenetic reprogramming or maternal provisioning.