Genomic characterization and expression profiles upon bacterial infection of a novel cystatin B homologue from disk abalone (Haliotis discus discus)

Premachandra, H.K.A.,Wan, Q.,Elvitigala, D.A.S.,De Zoysa, M.,Choi, C.Y.,Whang, I.,Lee, J. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2012 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.38 No.4

Cystatins are a large family of cysteine proteinase inhibitors which are involved in diverse biological and pathological processes. In the present study, we identified a gene related to cystatin superfamily, AbCyt B, from disk abalone Haliotis discus discus by expressed sequence tag (EST) analysis and BAC library screening. The complete cDNA sequence of AbCyt B is comprised of 1967 nucleotides with a 306bp open reading frame (ORF) encoding for 101 amino acids. The amino acid sequence consists of a single cystatin-like domain, which has a cysteine proteinase inhibitor signature, a conserved Gly in N-terminal region, QVVAG motif and a variant of PW motif. No signal peptide, disulfide bonds or carbohydrate side chains were identified. Analysis of deduced amino acid sequence revealed that AbCyt B shares up to 44.7% identity and 65.7% similarity with the cystatin B genes from other organisms. The genomic sequence of AbCyt B is approximately 8.4Kb, consisting of three exons and two introns. Phylogenetic tree analysis showed that AbCyt B was closely related to the cystatin B from pacific oyster (Crassostrea gigas) under the family 1.Functional analysis of recombinant AbCyt B protein exhibited inhibitory activity against the papain, with almost 84% inhibition at a concentration of 3.5μmol/L. In tissue expression analysis, AbCyt B transcripts were expressed abundantly in the hemocyte, gill, mantle, and digestive tract, while weakly in muscle, testis, and hepatopancreas. After the immune challenge with Vibrio parahemolyticus, the AbCyt B showed significant (P<0.05) up-regulation of relative mRNA expression in gill and hemocytes at 24 and 6h of post infection, respectively. These results collectively suggest that AbCyst B is a potent inhibitor of cysteine proteinases and is also potentially involved in immune responses against invading bacterial pathogens in abalone.

Analysis of the immune-inducible genes of Plutella xylostella using expressed sequence tags and cDNA microarray

Eum, J.H.,Seo, Y.R.,Yoe, S.M.,Kang, S.W.,Han, S.S. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2007 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.31 No.11

In the present study, the complex gene expression responses of Plutella xylostella to microbial challenges and injury were surveyed using a newly constructed expressed sequence tag (EST) clone collection and cDNA microarray analysis. A total of 1132 P. xylostella ESTs were cloned, annotated and categorized by their putative functions; these included proteases, protease inhibitors, recognition molecules and anti-microbial peptides. GeneOntology revealed that 4% of the P. xylostella ESTs corresponded to immunity-related genes potentially involved in innate immunity. We then used microarray analysis to identify 44 genes that were differentially expressed with at least a two-fold expression difference in P. xylostella before and after pathogen challenge. Together, our EST categorization and microarray profiling analyses allowed us to identify 70 genes that should be considered candidate immune response genes, providing important new insights into the molecular events that occur during the innate immune response in P. xylostella.

Seasonal variation and comparative analysis of non-specific humoral immune substances in the skin mucus of olive flounder (Paralichthys olivaceus)

Jung, T.S.,del Castillo, C.S.,Javaregowda, P.K.,Dalvi, R.S.,Nho, S.W.,Park, S.B.,Jang, H.B.,Cha, I.S.,Sung, H.W.,Hikima, J.i.,Aoki, T. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2012 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.38 No.2

The epidermal secretion of fish contains various non-specific immune substances that act as the first line of defense against invading pathogens. The present study investigated the level of mucosal antibodies, the activities of hemagglutinin and protease, and other enzymes in the skin mucus of farm reared olive flounder (Paralichthys olivaceus) for 1year, in order to gain an insight into the relationship between these mucosal immune substances and their seasonal variation. These levels varied significantly during different months of sample collection. The present study showed a positive correlation between water temperature and the level of mucosal antibodies, and an inverse relationship between the level of mucosal antibodies and the activity of mucosal hemagglutinin and protease, but no relationship between lysozyme activity and other innate immune substances. This relationship is thought to be a compensatory response in olive flounder to protect itself against pathogenic microorganisms which are inherently present in the aquatic environment.

Cytosolic thioredoxin from Ruditapes philippinarum: Molecular cloning, characterization, expression and DNA protection activity of the recombinant protein

Revathy, K.S.,Umasuthan, N.,Lee, Y.,Whang, I.,Kim, H.C.,Lee, J. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2012 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.36 No.1

Thioredoxin (TRx) is a small redox protein that plays significant roles in protection against oxidative stress and in cell homeostasis by maintaining oxidized proteins in a reduced state. Here, we describe the isolation and characterization of a full-length TRx cDNA sequence from manila clam, Ruditapes philippinarum and named it as RpTRx. The full length sequence consists of 1416bp with an open reading frame of 318bp encoding for 106 amino acids. RpTRx protein harbors evolutionarily-conserved TRx active site <SUP>32</SUP>WCGPC<SUP>36</SUP>. Phylogenetic analysis revealed a close proximity of RpTRx with the orthologue in Japanese scallop, Chlamys farreri. RpTRx was found to be constitutively expressed in hemocyte, gill, mantle, foot and siphon indicating a general role in physiological processes in various tissues. With regard to a potential role in immune responses, the RpTRx mRNA was found to be up-regulated in hemocytes after bacterial (Vibrio tapetis) and lipopolysaccharide (LPS) challenge at 3h post-infection (p.i.); a wavering increase was observed up to 96h p.i. for LPS challenge and 48h p.i. for bacterial challenge. Thus, RpTRx may function as an intracellular antioxidant to protect the cells against ROS induced by LPS and bacterial challenges. Indeed, when recombinant RpTRx protein (rRpTRx) was over-expressed in Escherichiacoli Rosetta gami<SUP>TM</SUP> (DE3) cells, it was able to scavenge free radicals and protect super-coiled DNA from oxidative damage induced by a metal-ion catalyzed oxidation reaction. In summary, RpTRx plays an essential role in cellular defense and maintenance of homeostasis in the manila clam.

Cathepsins in the kidney of olive flounder, Paralichthys olivaceus, and their responses to bacterial infection

Cha, I.S.,Kwon, J.,Mun, J.Y.,Park, S.B.,Jang, H.B.,Nho, S.W.,del Castillo, C.S.,Hikima, J.i.,Aoki, T.,Jung, T.S. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2012 Developmental and comparative immunology Vol.38 No.4

Cathepsin activities are responsible for mediating various pathways involved in immune response, including the apoptosis pathway, toll-like receptor (TLR) signaling, cytokine induction and activation of granule serine proteases. In the present study, we investigated cathepsin responses in the kidneys of olive flounder infected with Streptococcus parauberis, analyzing cathepsin expression using a label-free, quantitative proteomic approach in conjunction with quantitative real-time polymerase chain reaction (qRT-PCR). In proteomic analyses, we detected cathepsin B, D, L and S proteins, noting significant decreases and increases in cathepsins B and L, respectively, with infection. Taken together with an evaluation of cathepsin B, D, F, K, L, S and X gene expression in normal and infected kidneys by qRT-PCR, our results indicate that cathepsins B, D, L and S are the dominant lysosomal proteases in the immune system of the teleostei, olive flounder. Cathepsins F, K and X were regarded as minor cathepsins.

Activation of immune-associated phospholipase A₂ is functionally linked to Toll/Imd signal pathways in the red flour beetle, Tribolium castaneum

Shrestha, S.,Kim, Y. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2010 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.34 No.5

Bacterial challenge enhances phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>) activity, which in turn induces biosynthesis of various eicosanoids that mediate non-self recognition signal to immune effectors in insects. But, there is little information on how PLA<SUB>2</SUB> activity is controlled after the non-self recognition. A recent genome analysis of the red flour beetle, Tribolium castaneum, has annotated both Toll and Imd signal pathways that are presumably considered to specifically respond to different microbial infections to express specific antimicrobial peptides (AMPs). This study set up a hypothesis that PLA<SUB>2</SUB> activation is linked to Toll and Imd pathways in T. castaneum. Bacterial challenge to the larvae of T. castaneum induced expressions of Toll and Imd genes. Different AMP genes were induced in larvae infected with Gram-positive or -negative bacteria. RNA interference using double-stranded RNAs (dsRNAs) specific to different Toll and Imd genes showed differential inhibition of these AMP expressions, indicating that the Toll and Imd pathways play critical roles in the production of AMPs by specifically responding to various bacterial challenges in T. castaneum. These Toll and Imd immune signals are also linked to the activation of PLA<SUB>2</SUB> in T. castaneum. Activation of PLA<SUB>2</SUB> was significantly induced in response to bacterial challenge, but was inhibited by dsRNAs specific to different Toll and Imd genes. The activation of PLA<SUB>2</SUB> via Toll and Imd pathways could be explained by induction of PLA<SUB>2</SUB> gene expression because the dsRNA treatments of Toll and Imd genes suppressed the gene expression of PLA<SUB>2</SUB> in response to bacterial challenge. The functional links were further supported by an immunofluorescence assay of PLA<SUB>2</SUB> intracellular translocation. Upon bacterial challenge, hemocytes from control larvae showed intracellular translocation of their PLA<SUB>2</SUB>s near to cell membrane, but hemocytes from larvae treated with dsRNAs of the Toll and Imd genes did not show the translocation, at which the PLA<SUB>2</SUB>s appeared to be evenly spread in the cytoplasm. These results suggest that recognition of bacterial challenge initiates Toll and Imd pathways in T. castaneum, which subsequently induces the activation of immune-associated PLA<SUB>2</SUB>s as well as gene expression of various AMPs.

Rock bream (Oplegnathus fasciatus) serpin, protease nexin-1: Transcriptional analysis and characterization of its antiprotease and anticoagulant activities

Umasuthan, N.,Whang, I.,Kim, J.O.,Oh, M.J.,Jung, S.J.,Choi, C.Y.,Yeo, S.Y.,Lee, J.H.,Noh, J.K.,Lee, J. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2011 Developmental and comparative immunology Vol.35 No.7

Protease nexin-1 (PN-1) is a serine protease inhibitor (SERPIN) protein with functional roles in growth, development, patho-physiology and injury. Here, we report our work to clone, analyze the expression profile and characterize the properties of the PN-1 gene in rock bream (Rb), Oplegnathus fasciatus. RbPN-1 encodes a peptide of 397 amino acids (AA) with a predicted molecular mass of 44kDa and a 23 AA signal peptide. RbPN-1 protein was found to harbor a characteristic SERPIN domain comprised of a SERPIN signature and having sequence homology to vertebrate PN-1s. The greatest identity (85%) was observed with PN-1 from the three-spined stickleback fish, Gasterosteus aculeatus. The functional domains, including a heparin binding site and reactive centre loop were conserved between RbPN-1 and other fish PN-1s; in particular, they were found to correspond to components of the human plasminogen activator inhibitor 1, PAI-1. Phylogenetic analysis indicated that RbPN-1 was closer to homologues of green spotted pufferfish and Japanese pufferfish. Recombinant RbPN-1 demonstrated antiprotease activity against trypsin (48%) and thrombin (89%) in a dose-dependent manner, and its antithrombotic activity was potentiated by heparin. The anticoagulant function prolonged clotting time by 3.7-fold, as compared to the control in an activated partial thromboplastin time assay. Quantitative real-time PCR results indicated that RbPN-1 is transcribed in many endogenous tissues at different levels. Lipopolysaccharide (LPS) stimulated a prolonged transcriptional response in hematic cells, and Rb iridovirus up-regulated the RbPN-1 mRNA level in hematic cells to a maximum of 3.4-fold at 12h post-infection. Interestingly, LPS and Edwardsiella tarda significantly induced the RbPN-1 transcription at the late phase of infection. In vivo studies indicated that injury response caused a temporal suppression in RbPN-1 transcription, in conjunction with that of another SERPIN, rock bream heparin cofactor II, RbHCII. Taken together, our findings suggest that PN-1 functions as an antiprotease and anticoagulant and that SERPINs (PN-1 and HCII) are likely to contribute to immunity and post-injury responses.

Innate immunity and gut@?microbe mutualism in Drosophila

Ryu, J.H.,Ha, E.M.,Lee, W.J. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2010 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.34 No.4

Metazoan guts face a wide variety of microorganisms upon exposure to the environment, including beneficial symbionts, non-symbionts, food-borne microbes and life-threatening pathogens. Recent evidence has shown that the innate immunity of gut epithelia, such as anti-microbial peptide- and reactive oxygen species-based immune systems, actively participate in gut-microbe homeostasis by shaping the commensal community while efficiently eliminating unwanted bacteria. Therefore, elucidation of the regulatory mechanism by which gut innate immunity occurs at the molecular level will provide a novel perspective of gut-microbe mutualisms as well as of gut diseases caused by alterations in the innate immunity.

Chicken IL-17F: Identification and comparative expression analysis in Eimeria-infected chickens

Kim, W.H.,Jeong, J.,Park, A.R.,Yim, D.,Kim, Y.H.,Kim, K.D.,Chang, H.H.,Lillehoj, H.S.,Lee, B.H.,Min, W. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2012 Developmental and comparative immunology Vol.38 No.3

Interleukin-17F (IL-17F) is a proinflammatory cytokine, which plays an important role in gut homeostasis. A full-length chicken IL-17F (chIL-17F) cDNA with a 510-bp coding region was identified from ConA-activated chicken splenic lymphocytes. ChIL-17F shares 53% amino acid sequence identity with the previously described chicken IL-17 (chIL-17A) and 38-43% with mammalian homologues. The locus harboring chIL-17 and chIL-17F displayed inverted order compared to those of mammals. ChIL-17F transcript expression was high in lymphoblast cell line CU205 and at moderate levels in small and large intestines and liver. ChIL-17F and chIL-17 expression profiles were examined by quantitative real-time RT-PCR in mitogen-stimulated splenic lymphocytes and intestinal areas affected by Eimeria maxima and Eimeria tenella infections. Expression levels of chIL-17F, like chIL-17, were elevated in mitogen-activated splenic lymphocytes. ChIL-17F, but not chIL-17, expression was upregulated in intestinal tissues affected by E. maxima and E. tenella infections. Recombinant chIL-17F biological activities were similar to that of chIL-17 in primary chicken embryonic fibroblasts. These results suggest that chIL-17F is a unique member of the IL-17 family of cytokines.

Characterization and antiviral function of a cytosolic sensor gene, MDA5, in Japanese flounder, Paralichthys olivaceus

Ohtani, M.,Hikima, J.i.,Kondo, H.,Hirono, I.,Jung, T.S.,Aoki, T. Pergamon Press ; Elsevier Science Ltd ; Pergamon 2011 Developmental and comparative immunology Vol.35 No.5

Cytosolic pattern recognition receptors such as retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) play an important role in sensing viral RNAs. The receptor encoded by melanoma differentiation-associated gene 5 (MDA5), an RLR, recognizes viral RNA in the cytoplasm and enhances antiviral response in host cells. The full-length MDA5 gene in Japanese flounder, Paralichthys olivaceus was cloned and found to have 11,251 nucleotides. MDA5 transcript abundance was significantly increased in whole kidney infected with viral hemorrhagic septicemia virus (VHSV) as well as whole kidney and peripheral blood leukocytes stimulated with poly I:C in vitro. Hirame natural embryo (HINAE) cells overexpressing MDA5 showed a lower cytopathic effect (CPE) against VHSV, hirame rhabdovirus (HIRRV) and infectious pancreatic necrosis virus (IPNV) infection. When infected with VHSV, MDA5-overexpressing HINAE cells had 24-75 fold lower virus titer than normal HINAE cells. These results suggest that Japanese flounder MDA5 is involved in the induction of antiviral response.