| Authors | Lange, S., Gíslason, S., Needham, S.R., Davis, B.M., Kraev, I., Guls, H.D., Georgsdóttir, S.D., Kristmundsson, A and Halldórsson, H.P. |
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| Abstract | Crustacean shell disease is characterised by degradation of the chitinous exoskeleton, with subsequent microbial invasion and septicaemic infections, which can be exacerbated by environmental stressors including temperature fluctuations and pollutants. Recent research on shell disease in Atlantic rock crab (Cancer irroratus) in Icelandic waters has raised significant concern of potential impacts of this non-indigenous species on the native ecosystem. Increased understanding of cell communication mechanisms associated with shell disease is therefore important. Extracellular vesicles (EVs) play critical roles in cellular communication by cell-cell transfer of various cargo species and can be isolated from biofluids. To investigate systemic responses with respect to altered EV communication in C. irroratus with shell disease, this study assessed haemolymph EV profiles, including proteomic content, from infected and non-infected male and female crabs. Gene ontology and Reactome pathway enrichment analysis associated crab haemolymph EV protein cargoes with a range of immune, cell communication, membrane trafficking, vesicle-mediated transport cell cycle, signal transduction, transcriptional regulation, as well as DNA damage and repair response pathways. Overall, 34 proteins were identified with some sex-differences observed. Two proteins only identified in EV cargoes of infected male crabs were alpha-2-Macroglobulin, which has key innate immune functions, and actin-1 which has multifaceted roles in immunity and cell communication. Three proteins identified only in EV protein cargoes of the infected female crabs were Enkurin domain containing protein, which as roles in the cell cycle and DNA repair; ribosomal protein Lu5, which has roles in translation, metabolism and RNA processing; and Discoidal lipoprotein and beta-glucan binding protein with unidentified roles. Concentration of EVs in haemolymph was elevated in the male crabs with shell disease, compared with non-infected individuals and some changes were observed in EV subpopulation dynamics between male and female crabs in response to infection, based on nanoparticle tracking analysis and single-molecule localisation-based super-resolution microscopy imaging of crab haemolymph EVs. The findings pave way for using haemolymph EVs as biomarkers for monitoring disease responses in marine shellfish, with potential for translatability for studying disease epidemics in invasive marine species globally. |
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