A role of tumor susceptibility gene 101 (TSG101) in innate immune response of crayfish Procambarus clarkii

Ferritin Heavy-like subunit is involved in the innate immune defense of the red swamp crayfish Procambarus clarkii

Iron-binding proteins, known as ferritins, play pivotal roles in immunological response, detoxification, and iron storage. Despite their significance to organisms, little is known about how they affect the immunological system of the red swamp crayfish (Procambarus clarkii). In our previous research, one ferritin subunit was completely discovered as an H-like subunit (PcFeH) from P. clarkii. The full-length cDNA of PcFerH is 1779 bp, including a 5'-UTR (untranslated region, UTR) of 89 bp, 3'-UTR (untranslated region, UTR) of 1180 bp and an ORF (open reading frame, ORF) of 510 bp encoding a polypeptide of 169 amino acids that contains a signal peptide and a Ferritin domain. The deduced PcFerH protein sequence has highly identity with other crayfish. PcFerH protein's estimated tertiary structure is quite comparable to animal structure. The PcFerH is close to Cherax quadricarinatus, according to phylogenetic analysis. All the organs examined showed widespread expression of PcFerH mRNA, with the ovary exhibiting the highest levels of expression. Additionally, in crayfish muscles, intestines, and gills, the mRNA transcript of PcFerH was noticeably up-regulated, after LPS and Poly I:C challenge. The expression of downstream genes in the immunological signaling system was suppressed when the PcFerH gene was knocked down. All of these findings suggested that PcFerH played a vital role in regulating the expression of downstream effectors in the immunological signaling pathway of crayfish.

Robust strategy for disease resistance and increasing production breeding in red swamp crayfish (Procambarus clarkii)

Red swamp crayfish (Procambarus clarkii) is an important aquaculture species in China. With increasing crayfish culture, a number of outbreaks of various diseases have been identified in crayfish. Despite this, there are no reports on the application of disease resistance genes in the molecular breeding of crayfish. In this study, transcriptome analysis was performed to explore the disease resistance genes in crayfish, with a focus on investigating the genetic variations in the open reading frames of these genes, for subsequent haplotype analysis. Furthermore, pathogen-challenge experiments were carried out in the crayfish, to identify the favoured haplotypes. A novel disease resistance gene, R (Resistance), was identified by means of transcriptome analysis. In total, two, four, and five haplotypes of the three disease resistance genes, ALF, R, and crustin2, respectively, were detected. ALF1, R1, and Cru1 were the favoured haplotypes of ALF, R, and crustin2, respectively. Subsequently, the favoured haplotype combinations of the different genes were obtained, and a series of molecular markers were developed to identify them. Finally, we propose a molecular breeding strategy to enhance the disease resistance of crayfish, and thus, improve its production.

Spatiotemporal proteomic profiling of the pro-inflammatory response to lipopolysaccharide in the THP-1 human leukaemia cell line

Protein localisation and translocation between intracellular compartments underlie almost all physiological processes. The hyperLOPIT proteomics platform combines mass spectrometry with state-of-the-art machine learning to map the subcellular location of thousands of proteins simultaneously. We combine global proteome analysis with hyperLOPIT in a fully Bayesian framework to elucidate spatiotemporal proteomic changes during a lipopolysaccharide (LPS)-induced inflammatory response. We report a highly dynamic proteome in terms of both protein abundance and subcellular localisation, with alterations in the interferon response, endo-lysosomal system, plasma membrane reorganisation and cell migration. Proteins not previously associated with an LPS response were found to relocalise upon stimulation, the functional consequences of which are still unclear. By quantifying proteome-wide uncertainty through Bayesian modelling, a necessary role for protein relocalisation and the importance of taking a holistic overview of the LPS-driven immune response has been revealed. The data are showcased as an interactive application freely available for the scientific community.

Extracellular vesicles and post-translational protein deimination signatures in haemolymph of the American lobster (Homarus americanus)

The American lobster (Homarus americanus) is a commercially important crustacean with an unusual long life span up to 100 years and a comparative animal model of longevity. Therefore, research into its immune system and physiology is of considerable importance both for industry and comparative immunology studies. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family that catalyses post-translational protein deimination via the conversion of arginine to citrulline. This can lead to structural and functional protein changes, sometimes contributing to protein moonlighting, in health and disease. PADs also regulate the cellular release of extracellular vesicles (EVs), which is an important part of cellular communication, both in normal physiology and in immune responses. Hitherto, studies on EVs in Crustacea are limited and neither PADs nor associated protein deimination have been studied in a Crustacean species. The current study assessed EV and deimination signatures in haemolymph of the American lobster. Lobster EVs were found to be a poly-dispersed population in the 10-500 nm size range, with the majority of smaller EVs, which fell within 22-115 nm. In lobster haemolymph, 9 key immune and metabolic proteins were identified to be post-translationally deiminated, while further 41 deiminated protein hits were identified when searching against a Crustacean database. KEGG (Kyoto encyclopedia of genes and genomes) and GO (gene ontology) enrichment analysis of these deiminated proteins revealed KEGG and GO pathways relating to a number of immune, including anti-pathogenic (viral, bacterial, fungal) and host-pathogen interactions, as well as metabolic pathways, regulation of vesicle and exosome release, mitochondrial function, ATP generation, gene regulation, telomerase homeostasis and developmental processes. The characterisation of EVs, and post-translational deimination signatures, reported in lobster in the current study, and the first time in Crustacea, provides insights into protein moonlighting functions of both species-specific and phylogenetically conserved proteins and EV-mediated communication in this long-lived crustacean. The current study furthermore lays foundation for novel biomarker discovery for lobster aquaculture.

Roles of a small GTPase Sar1 in ecdysteroid signaling and immune response of red swamp crayfish Procambarus clarkii

Secretion-associated and ras-related protein 1 (Sar1) is a small GTPase that plays an important role in the transport of protein coated with coat protein complex II vesicles. However, its alternative roles in the biological processes of Procambarus clarkii remain unclear. Here, a sar1 gene (named as Pc-sar1) with an open reading frame of 582 bp from P. clarkii was identified. Pc-sar1 was expressed in all examined tissues with highest expression levels in muscle, which was determined by real-time PCR and western blotting. After the induction of lipopolysaccharide (LPS) and polycytidylic acid (Poly I: C), the transcriptional levels of Pc-sar1 differed in hepatopancreas, gill, muscle and intestine. In contrast, the expression of Pc-sar1 was upregulated by 20-hydroxyecdysone in these four tissues. In addition, the RNA interference of Pc-sar1 significantly affected the expression levels of immune and hormone-related genes. These results indicate that Pc-sar1 is involved in the innate immune response and ecdysteroid signaling pathway.

Characterization of small GTPase Rac1 and its interaction with PAK1 in crayfish Procambarus clarkii

Ras-related C3 botulinum toxin substrate 1 (Rac1) participates in many biological processes. In this study, a Rac1 gene was identified in the crayfish Procambarus clarkii with an open reading frame of 579 bp that encoded 192 amino acids. This predicted 21.4 kDa protein was highly homologous to those in other invertebrates. Real-time PCR analysis revealed that Pc-Rac1 was expressed in all examined tissues with the highest expression level in hemocytes. The transcriptional expression level of Pc-Rac1 was significantly upregulated in hemocytes and hepatopancreas after lipopolysaccharide (LPS) or polyinosinic: polycytidylic acid (poly I: C) induction. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis suggested that a recombinant Pc-Rac1 protein was successfully expressed in E. coli. Far-western blot analysis demonstrated that Rac1 can interact with the PBD domain of p21-activated kinase 1 (PAK1). RNA interference of Pc-Rac1 affected the mRNA expression levels of immune-related genes lectin, Toll, crustin, TNF, ALF and cactus. These results suggest that Pc-Rac1 is involved in the innate immune responses in P. clarkii.