Heat shock protein profiles on the protein and gene expression levels in olive flounder kidney infected with Streptococcus parauberis

Intermolecular Interactions between Cysteine and Aromatic Amino Acids with a Phenyl Moiety in the DNA-Binding Domain of Heat Shock Factor 1 Regulate Thermal Stress-Induced Trimerization

In this study, we investigated the trimerization mechanism and structure of heat shock factor 1 (HSF1) using western blotting, tryptophan (Trp) fluorescence spectroscopy, and molecular modeling. First, we examined the DNA-binding domains of human (Homo sapiens), goldfish (Carassius auratus), and walleye pollock (Gadus chalcogrammus) HSF1s by mutating key residues (36 and 103) that are thought to directly affect trimer formation. Human, goldfish, and walleye pollock HSF1s contain cysteine at residue 36 but cysteine (C), tyrosine (Y), and phenylalanine (F), respectively, at residue 103. The optimal trimerization temperatures for the wild-type HSF1s of each species were found to be 42, 37, and 20 °C, respectively. Interestingly, a mutation experiment revealed that trimerization occurred at 42 °C when residue 103 was cysteine, at 37 °C when it was tyrosine, and at 20 °C when it was phenylalanine, regardless of the species. In addition, it was confirmed that when residue 103 of the three species was mutated to alanine, trimerization did not occur. This suggests that in addition to trimerization via disulfide bond formation between the cysteine residues in human HSF1, trimerization can also occur via the formation of a different type of bond between cysteine and aromatic ring residues such as tyrosine and phenylalanine. We also confirmed that at least one cysteine is required for the trimerization of HSF1s, regardless of its position (residue 36 or 103). Additionally, it was shown that the trimer formation temperature is related to growth and survival in fish.

Effect of Air Exposure and Re-Submersion on the Histological Structure, Antioxidant Response, and Gene Expression of Procambarus Clarkii

Air exposure is an important environmental stressor during the transportation and cultivation of Procambarus clarkii. We evaluated the effect of re-submersion for 24 h after dry transportation for 24 h on the histological structure, antioxidant activity, and gene expression of crayfish. The antioxidant parameters of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and lactate dehydrogenase (LDH), and the relative expression of CAT, SOD, HSP70, and ferritin genes were subsequently measured in the hepatopancreas and gills at both stages. Histopathology found that air exposure led to vacuolation of the hepatopancreas and disorderly arrangement of respiratory epithelial cells (REC) in the gills. The activities of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and lactic dehydrogenase (LDH) in the hepatopancreas and gills increased with short-term air exposure. The relative expression of genes (CAT, SOD, HSP70, and Ferritin) were induced after short-term air exposure. During re-submersion, MDA content and CAT and SOD activities in the hepatopancreas and gills were restored after 24 h, however, LDH activity and hepatopancreatic tissue damage were not repaired. Our results indicate that air exposure can cause oxidative damage to P. clarkii, and CAT and SOD can be used to determine the response of crayfish exposed to air, in addition to some damage that can be eliminated after re-submersion to a limited degree. This study provides foundational data that re-submersion can improve crayfish performance under hypoxic stress to a certain extent and will lead to the development of more effective transportation strategies and decrease economic losses in the future.

Gene ssa-miR-301a-3p improves rainbow trout (Oncorhynchus mykiss) resistance to heat stress by targeting hsp90b2

Rainbow trout (Oncorhynchus mykiss) is a cold-water fish that is commonly harmed by high temperatures. MicroRNAs (miRNAs) are being investigated intensively because they act as essential metabolic regulators and have a role in the heat stress response. Although there have been numerous studies on rainbow trout heat stress, research on miRNA implicated in rainbow trout heat stress is quite restricted. Rainbow trout were sampled at 18 and 24 °C, respectively, to examine the mechanism of miRNA under heat stress, and we identified a heat stress-induced miRNA, ssa-miR-301a-3p, for further investigation based on our bioinformatics analysis of rainbow trout small RNA sequencing data. Bioinformatics research suggested that hsp90b2 is a probable target gene for ssa-miR-301a-3p. QRT-PCR was used to confirm the expression levels of ssa-miR-301a-3p and hsp90b2. Meanwhile, the dual-luciferase reporter assay was employed to validate the ssa-miR-301a-3p-hsp90b2 targeted connection. The results indicated that at 24 °C, the relative expression of ssa-miR-301a-3p was considerably lower than at 18 °C. On the other hand, hsp90b2 expression, followed the opposite pattern. The binding of ssa-miR-301a-3p to the 3'-UTR of hsp90b2 resulted in a substantial decrease in luciferase activity. The findings showed that ssa-miR-301a-3p was implicated in heat stress, and our findings provide fresh insights into the processes of miRNA in response to heat stress in rainbow trout.

Molecular Characterization and Defense Functions of the Nile Tilapia (Oreochromis niloticus) DnaJ B9b and DnaJ C3a Genes in Response to Pathogenic Bacteria under High-Temperature Stress Conditions

DnaJ proteins or heat shock protein 40s (HSP40s) form one of the largest heat shock protein families. In this study, 2 cDNAs encoding Nile tilapia (Oreochromis niloticus) DnaJ proteins (On-DnaJ B9b and On-DnaJ C3a) were successfully cloned and characterized. The structures and organizations of these two genes are first reported in the present study. On-DnaJ B9b is approximately 2.1 kb long and contains 2 exons and 1 intron, while On-DnaJ C3a is approximately 12 kb long and contains 12 exons and 11 introns. Under normal conditions, On-DnaJ B9b mRNA is highly expressed in gonad and trunk kidney tissues, while On-DnaJ C3a transcripts are abundantly expressed in gills, intestine, liver, and trunk kidney tissues. Following pathogenic infections, the expression of both genes is induced in the liver, spleen and head kidney tissues of Nile tilapia that were infected with two virulent pathogenic bacteria, Streptococcus agalactiae and Flavobacterium columnare. Silencing of these two genes was first carried out, and the results clearly indicated their crucial roles under both heat and bacterial stress conditions. The fundamental knowledge obtained from this study indicates the characteristic basic biofunctions of heat shock proteins in the regulation of intracellular proteins during infection, which involve preventing protein aggregation, promoting protein refolding, and activating unfolded protein degradation.

Gene expression profiles alteration after infection of virus, bacteria, and parasite in the Olive flounder (Paralichthys olivaceus)

Olive flounder (Paralichthys olivaceus) is one of economically valuable fish species in the East Asia. In comparison with its economic importance, available genomic information of the olive flounder is very limited. The mass mortality caused by variety of pathogens (virus, bacteria and parasites) is main problem in aquaculture industry, including in olive flounder culture. In this study, we carried out transcriptome analysis using the olive flounder gill tissues after infection of three types of pathogens (Virus; Viral hemorrhagic septicemia virus, Bacteria; Streptococcus parauberis, and Parasite; Miamiensis avidus), respectively. As a result, we identified total 12,415 differentially expressed genes (DEG) from viral infection, 1,754 from bacterial infection, and 795 from parasite infection, respectively. To investigate the effects of pathogenic infection on immune response, we analyzed Gene ontology (GO) enrichment analysis with DEGs and sorted immune-related GO terms per three pathogen groups. Especially, we verified various GO terms, and genes in these terms showed down-regulated expression pattern. In addition, we identified 67 common genes (10 up-regulated and 57 down-regulated) present in three pathogen infection groups. Our goals are to provide plenty of genomic knowledge about olive flounder transcripts for further research and report genes, which were changed in their expression after specific pathogen infection.

The GRP94 gene of Yesso scallop (Patinopecten yessoensis): Characterization and expression regulation in response to thermal and bacterial stresses

The 94-kDa glucose-regulated protein (GRP94) belonging to the HSP90 family is an endoplasmic reticulum (ER) chaperone. It plays critical roles in ER quality control, and has been implicated as a specialized immune chaperone to regulate both innate and adaptive immunity. In this study, we identified and characterized a GRP94 gene (PyGRP94) from Yesso scallop (Patinopecten yessoensis). The protein sequence of PyGRP94 is highly conserved with its homologs in vertebrates, with a signal sequence in N-terminal, an ER retrieval signal sequence in C-terminal and a HATPase_c domain. Expression analysis suggests that PyGRP94 transcripts in early embryos are maternally derived and the zygotic expression is started from D-shaped larvae. This gene is also expressed in almost all the adult tissues examined except smooth muscle, with the highest expression level in hemocytes. Besides, PyGRP94 was demonstrated to be induced by heat shock and both Gram-positive (Micrococcus luteus) and Gram-negative (Vibrio anguillarum) bacterial infection, with much more dramatic changes being observed after V. anguillarum challenge. Our results suggest the involvement of PyGRP94 in response to thermal stress, and that it might play an important role in the innate immune defense of scallop.

LncRNA and mRNA profiling during activation of tilapia macrophages by HSP70 and Streptococcus agalactiae antigen

Objectives

To investigate the lncRNA profiling during tilapia peritoneal macrophages (TPMs) activation and discuss the relationship between lncRNA and mRNA.

Materials and Methods

RNA sequencing was used to investigate the lncRNA and mRNA profiles of TPMs activation following stimulation with Streptococcus agalactiae (Sa) antigen, heat shock protein 70 (HSP70) and HSP70+Sa. The expressions of lncRNA and mRNA were confirmed by qPCR. 356 lncRNA, 10173 mRNA and 1782 transcripts of uncertain coding potential (TUCP) were differentially expressed by pairwise comparison. These lncRNAs were shorter in length, fewer in exon number and higher in expression levels as compared with mRNAs. 683 lncRNAs and 4320 mRNAs were co-located, while 316 lncRNAs and 9997 mRNAs were in co-expression networks. Seven mRNAs (ANKRD34A, FMODA, GJA3, CNTN5, BMP10, BAI2 and HS3ST6) were involved in both networks of LNC_00035 and LNC_000466. Differentially expressed genes were involved in signaling pathways, such as "phosphorylation", "cytokine-cytokine receptor interaction", "endocytosis" and "MHC protein complex". LNC_000792, LNC_000215, LNC_000035 and LNC_000310, with cis and/or trans relationships with mRNAs, were also involved in ceRNA network.

Conclusions

These results might represent the first identified expression profile of lncRNAs and mRNAs in tilapia macrophages activated by HSP70 and Sa.

Molecular characterization and expression analysis of Hsp90 in Schizothorax prenanti

Aquatic animals suffer from various environmental stresses because the aquatic environment is a very complex system. To monitor the health status of fish, Hsp90 a potential early warning marker was determined in Schizothorax prenanti after infection with a bacterium. In this study, we cloned Hsp90 from S. prenanti for the first time. The full-length cDNA sequence of SpHsp90 was 2663 bp, contains an open reading frame of 2181 bp, and has a gene encoding 726 amino acids, an estimated molecular mass of 83.38 kDa, and a theoretical isoelectric point of 4.91. The SpHsp90 amino acid sequence has five conserved HSP90 family signatures and shares 87.0-95.5 % identity with other vertebrates. Phylogenetic analysis and structure comparison indicated that SpHsp90 should be a β isoform of the HSP90 family. SpHsp90 was ubiquitously expressed in all examined tissues, and the highest level of expression was in the kidney. After Streptococcus agalactiae infection, the level of SpHsp90 expression had significant changes (P < 0.05) in the hepatopancreas, spleen, kidney, and blood. The expression increased to the highest level at 6 h in the blood and at 24 h in the hepatopancreas, spleen, and kidney. The results suggested that the SpHsp90 gene could be induced by S. agalactiae in S. prenanti and that SpHsp90 may be involved in resistance to bacterial infection and provide an early warning information. The kidney is the most suitable for detecting SpHsp90 after bacterial infection.

Hsp90, Hsp60 and sHsp families of heat shock protein genes in channel catfish and their expression after bacterial infections

Heat shock proteins (Hsps) are a suite of highly conserved proteins whose expressions are generally induced by elevated temperature. However, many Hsps play important roles in both innate and adaptive immunity. On the basis of our previous work on Hsp40 and Hsp70 gene families in channel catfish (Ictalurus punctatus), the objective of this study was to characterize Hsp90, Hsp60, Hsp10, and small Hsp genes, and to investigate their expression profiles after bacterial infections. A total of 20 Hsp genes were identified and annotated in the channel catfish genome, including five Hsp90 genes, one Hsp60 gene, one Hsp10 gene, and 13 sHsp genes. Six Hsp genes were differentially expressed after Edwardsiella ictaluri infection, and 12 were differentially expressed after Flavobacterium columnare infection. Although expression of these genes exhibited both temporal and spatial regulation, the induction of Hsp genes was observed soon after bacterial infection, while the suppression of Hsp genes was observed at later time-points, suggesting their distinct roles in immune responses and disease defenses. A pathogen-specific expression pattern of Hsp90 was observed. After F. columnare infection, all Hsp90 genes were found up-regulated except Hsp90ab1, which was not significantly regulated. However, after E. ictaluri infection, only one Hsp90 gene was found significantly down-regulated. Both pathogen-specific and tissue-specific pattern of expression were observed with small Hsps after E. ictaluri and F. columnare bacterial infections. These results suggested that most of Hsp genes may play important roles in immune response and/or disease defense in channel catfish.

Expression analysis of heat shock protein genes during Aeromonas hydrophila infection in rohu, Labeo rohita, with special reference to molecular characterization of Grp78

Heat shock protein (Hsp) genes are stress-related genes that activate the host immune system during infection. Hsp genes expression in fish, studied during bacterial infections, is mostly confined to Hsp70 and Hsp90. The present study is an expression analysis of seven Hsp genes: Apg2, Hsp90, Hsp70, glucose-regulated protein 78 (Grp78), heat shock cognate 70 (Hsc70), Grp75, and Hsp30 during Aeromonas hydrophila infection in rohu, Labeo rohita. Forty-eight rohu juveniles were challenged with 3 × 10(7) cfu bacteria per 20 g of body weight intraperitoneally. The expression of these genes was studied in infected liver, anterior kidney, and spleen tissues of rohu at different time periods: 0, 1, 3, 6, 12, 24, 48, 72 h, 7, and 15 days post-infection by qPCR. The Hsp gene modulation was greater in liver as compared to spleen and kidney tissues. Induced expression of Apg2, Hsp90, Grp78, Grp75, and Hsc70 was noticed during peak periods (3 to 24 h post-challenge) of bacterial infectivity. Hsp70 was found to be down-regulated during the process of infection. In contrast to the other six genes, Hsp30 showed a variable expression pattern in all three tissues. Grp78 was found to be the most highly (1,587-fold) expressed gene in liver at 12 h post-challenge. Further, molecular characterization of Grp78 revealed it to be a highly conserved Hsp gene, essential not only during infection but also during early developmental stages of rohu, and its expression was noticed in all organs studied except in gill tissues, which indicated its potential immune regulatory role during infection process.

Genome-wide identification of hsp40 genes in channel catfish and their regulated expression after bacterial infection

Heat shock proteins (HSPs) consist of a large group of chaperones whose expression is induced by high temperature, hypoxia, infection and a number of other stresses. Among all the HSPs, Hsp40 is the largest HSP family, which bind to Hsp70 ATPase domain in assisting protein folding. In this study, we identified 57 hsp40s in channel catfish (Ictalurus punctatus) through in silico analysis using RNA-Seq and genome databases. These genes can be classified into three different types, Type I, II and III, based on their structural similarities. Phylogenetic and syntenic analyses provided strong evidence in supporting the orthologies of these HSPs. Meta-analyses of RNA-Seq datasets were conducted to analyze expression profile of Hsp40s following bacterial infection. Twenty seven hsp40s were found to be significantly up- or down-regulated in the liver after infection with E. ictaluri; 19 hsp40s were found to be significantly regulated in the intestine after infection with E. ictaluri; and 19 hsp40s were found to be significantly regulated in the gill following infection with F. columnare. Altogether, a total of 42 Hsp40 genes were regulated under disease situations involving three tissues and two bacterial infections. The significant regulated expression of Hsp40 genes after bacterial infection suggested their involvement in disease defenses in catfish.

Modulation of proteome expression by F-type lectin during viral hemorrhagic septicemia virus infection in fathead minnow cells

Lectins found in fish tissues play an important role in the innate immune response against viral infection. A fucose-binding type lectin, RbFTL-3, from rock bream (Oplegnathus fasciatus) was identified using expressed sequence tag (EST) analysis. The expression of RbFTL-3 mRNA was higher in intestine than other tissues of rock bream. To determine the function of RbFTL-3, VHSV-susceptible fathead minnow (FHM) cells were transfected with pcDNA3.1(+) or pcDNA3.1(+)-RbFTL-3 and further infected with VHSV. The results show that the viability of FHM cells transfected with pcDNA3.1(+)-RbFTL-3 is higher than that of cells transfected with pcDNA3.1(+) (relative cell viability: 28.9% vs 56.2%). A comparative proteomic analysis, performed to explore the proteins related to the protective effect of RbFTL-3 in the cells during VHSV infection, identified 90 proteins differentially expressed in VHSV-infected FHM cells transfected with pcDNA3.1(+) or pcDNA3.1(+)-RbFTL-3. The expression of RbFTL-3 inhibits a vascular-sorting protein (SNF8) and diminishes the loss of prothrombin, which are closely associated with controlling viral budding and hemorrhage in fish cells, respectively. Subsequent Ingenuity Pathways Analysis enabled prediction of their biofunctional groupings and interaction networks. The results suggest RbFTL-3 modulates the expression of proteins related to viral budding (SNF8, CCT5 and TUBB) and thrombin signaling (F2) to increase the viability of VHSV infected cells.

Molecular characterization of heat shock protein 70 (HSP 70) promoter in Japanese flounder (Paralichthys olivaceus), and the association of Pohsp70 SNPs with heat-resistant trait

Ambient temperature is one of the major abiotic environmental factors determining the main parameters of fish vital activity. HSP70 plays an essential role in heat response. In this investigation, the promoter and structure of Paralichthys olivaceus hsp70 (Pohsp70) gene was cloned and predicted. 2558 bp upstream regulatory region of Pohsp70 was annotated with four potential promoter elements and four putative binding sites of transcription factors heat shock elements (HSE, nGAAn) in the upstream of the transcription start site. In addition, one intron with 454 bp in the 5'-noncoding region was found. Quantitative Real Time PCR analysis indicated that the transcript level of Pohsp70 was raised markedly after 1 h by heat shocked. Furthermore, 25 SNPs were identified in Pohsp70 by resequencing, seven of which was associated with heat resistance. In addition, two of the seven SNPs, namely SNP14 and SNP16, were observed in strong linkage disequilibrium. The haplotype with association analysis showed TAGGAG haplotype was more represented in heat susceptible group while (DEL/T) GAATA haplotype was more frequent in heat resistant group. The heat resistant SNPs and haplotype could be candidate markers potentially serving for selective breeding programs of Japanese flounder aimed at improving anti-stress and production.

Hsp60 in caudal fin regeneration from Paramisgurnus dabryanus: molecular cloning and expression characterization

Heat shock protein 60 (Hsp60) is a kind of highly conserved immunogenic molecule involved in a wide range of biochemical processes in response to external stressors. Its multifunction in regulating immune responses and modulating signal pathway interests us in investigating its role in fin regeneration that has become an excellent and interesting model for studying the molecular basis of morphogenesis. We firstly clarified basical process and crucial period of caudal fins regeneration in Paramisgurnus dabryanus by histological analysis. Then we cloned full-length cDNA of hsp60 from P. dabryanus (designated as PdHsp60) by RACE method. The cDNA contains a 124 bp 5'UTR, a 1731 bp open reading frame (ORF) encoding 576 amino acids and a 510 bp 3'UTR (Accession no.: KF544774). The phylogenetic tree shows that the PdHsp60 fits within the hsp60 clade. And quantitative RT-PCR detected the PdHsp60 began to increase rapidly its expression at 1 dpa and reached its peak at 2 dpa. Next, spatial distribution analysis of PdHsp60 in fins showed that PdHsp60 located mainly in the deeper lay of regenerated epidermis when PdHsp60 expressed most. After the PdHsp60 had been cloned into the pET-32a vector, SDS-PAGE and Western blotting analysis confirmed that the PdHsp60 protein was efficiently expressed in Escherichia coli BL21. These findings have revealed that PdHsp60, a highly conserved gene related to the innate immune system and stress response during vertebrate evolution, is involved in response to wounding stimulation--in the formation of wound epidermis which occurs as the first phase of fin regeneration after fin amputation in caudal fin regeneration.

Molecular cloning, characterization, and expression of hsp60 in caudal fin regeneration of Misgurnus anguillicaudatus

Urodele amphibians and teleost fish are capable of nearly perfect regeneration of lost appendages. The fin constitutes an important model for studying the molecular basis of tissue regeneration. It has been known that heat shock protein 60 (Hsp60) is a multifunctional protein of the heat shock protein family. The purpose of this study is to investigate the role of hsp60 as a part of a stress response system after fin injury or in fin regeneration. We firstly cloned full-length cDNA of hsp60 from Misgurnus anguillicaudatus (designated as MaHsp60) by RACE method. The cDNA contains a 83-bp 5'UTR, a 1,728-bp open reading frame encoding 492 amino acids and a 542-bp 3'UTR (Accession No.: KF537340). The phylogenetic tree shows that the MaHsp60 fits within the hsp60 clade. Then quantitative RT-PCR detected that MaHsp60 began to increase rapidly its expression at 1 dpa and reached its peak at 2 dpa. Next, spatial distribution analysis of MaHsp60 in fins showed that MaHsp60 located mainly in the deeper layer of regenerated epidermis when MaHsp60 expressed most. After the MaHsp60 had been cloned into the pET-32a vector, SDS-PAGE analysis confirmed that the MaHsp60 protein was efficiently expressed in Escherichia coli BL21 and adjustable with the temperature. These findings have revealed that MaHsp60, a highly conserved gene during vertebrate evolution as well as related to stress response, is involved in the formation of wound epidermis which occurs as the first phase of fin regeneration after fin amputation in caudal fin regeneration.