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Fish & Shellfish Immunology May 2020Astragalus polysaccharides (APS) have been widely used as immunopotentiators in aquaculture, however, the best way of their administration remains to be explored. In the...
Astragalus polysaccharides (APS) have been widely used as immunopotentiators in aquaculture, however, the best way of their administration remains to be explored. In the present study, APS liposome (APSL) was prepared by film dispersion-ultrasonic method. The optimal conditions of APSL preparation were determined by response surface methodology, with a ratio of 10:1 (w/w) for soybean lecithin to APS and 8:1 (w/w) for soybean lecithin to cholesterol, and an ultrasound time of 15 min, which produced an encapsulation efficiency of 73.88 ± 0.88% of APSL. In vivo feeding experiments in large yellow croaker showed that both APS and APSL could enhance the contents of serum total protein (TP) and albumin (ALB), activities of serum non-specific immune enzymes such as acid phosphatase (ACP), alkaline phosphatase (AKP), and lysozyme (LZM), and phagocytic activity of head kidney macrophages. Meanwhile, they both increased the activities of serum antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and reduced the content of final lipid peroxidation product malondialdehyde (MDA) in serum, thus exhibiting the antioxidant effects. In vitro experiments on primary head kidney macrophages (PKM) showed that both APS and APSL inhibited ROS production, but obviously enhanced NO production and phagocytic activity of PKM. Furthermore, expression levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α), IFN-γ, and iNOS in PKM were significantly up-regulated after APS and APSL treatments, but no expression change of IFN-h was observed. Taken together, our results showed that both APS and APSL could improve several immune parameters and antioxidant ability of large yellow croaker either in vivo or in vitro, and the efficacy of APSL was markedly better than APS. These findings therefore indicated that the immunomodulatory and antioxidant activities of APS could be enhanced after encapsulated with liposome, and APSL may represent a potential drug delivery system of APS for development of immunoenhancers in aquaculture.
Topics: Animals; Antioxidants; Aquaculture; Astragalus Plant; Blood Proteins; Head Kidney; Immunologic Factors; Liposomes; Macrophages; Perciformes; Phagocytosis; Plant Extracts; Serum Albumin
PubMed: 32142872
DOI: 10.1016/j.fsi.2020.03.004 -
BMC Genomics Nov 2022Infectious Salmon Anaemia virus (ISAV) is an orthomyxovirus responsible for large losses in Atlantic salmon (Salmo salar) aquaculture. Current available treatments and...
BACKGROUND
Infectious Salmon Anaemia virus (ISAV) is an orthomyxovirus responsible for large losses in Atlantic salmon (Salmo salar) aquaculture. Current available treatments and vaccines are not fully effective, and therefore selective breeding to produce ISAV-resistant strains of Atlantic salmon is a high priority for the industry. Genomic selection and potentially genome editing can be applied to enhance the disease resistance of aquaculture stocks, and both approaches can benefit from increased knowledge on the genomic mechanisms of resistance to ISAV. To improve our understanding of the mechanisms underlying resistance to ISAV in Atlantic salmon we performed a transcriptomic study in ISAV-infected salmon with contrasting levels of resistance to this virus.
RESULTS
Three different tissues (gills, head kidney and spleen) were collected on 12 resistant and 12 susceptible fish at three timepoints (pre-challenge, 7 and 14 days post challenge) and RNA sequenced. The transcriptomes of infected and non-infected fish and of resistant and susceptible fish were compared at each timepoint. The results show that the responses to ISAV are organ-specific; an important response to the infection was observed in the head kidney, with up-regulation of immune processes such as interferon and NLR pathways, while in gills and spleen the response was more moderate. In addition to immune related genes, our results suggest that other processes such as ubiquitination and ribosomal processing are important during early infection with ISAV. Moreover, the comparison between resistant and susceptible fish has also highlighted some interesting genes related to ubiquitination, intracellular transport and the inflammasome.
CONCLUSIONS
Atlantic salmon infection by ISAV revealed an organ-specific response, implying differential function during the infection. An immune response was observed in the head kidney in these early timepoints, while gills and spleen showed modest responses in comparison. Comparison between resistance and susceptible samples have highlighted genes of interest for further studies, for instance those related to ubiquitination or the inflammasome.
Topics: Animals; Isavirus; Head Kidney; Salmo salar; Spleen; Gills; Transcriptome; Inflammasomes
PubMed: 36443659
DOI: 10.1186/s12864-022-09007-4 -
Fish & Shellfish Immunology Dec 2022CD4 and CD8 molecules play an important role in the identification of T lymphocytes, and diverse among fish species. In this study, CD4-1 and CD8α gene of spotted sea...
CD4-1 and CD8α T lymphocytes subsets in spotted sea bass (Lateolabrax maculatus) and comparison on antigenicity of T lymphocytes subsets in other three marine fish species.
CD4 and CD8 molecules play an important role in the identification of T lymphocytes, and diverse among fish species. In this study, CD4-1 and CD8α gene of spotted sea bass (Lateolabrax maculatus) were cloned, polyclonal antibodies against CD4-1 (CD4-1 pAbs) and CD8α (CD8α pAbs) were produced, respectively. And the variations in CD4-1 and CD8α T-lymphocytes in spotted sea bass and the cross-reactivity with leukocytes in pearl gentian grouper (Epinephelus fuscoguttatus x E. lanceolatus), schlegel's black rockfish (Sebastes schlegelii) and flounder (Paralichthys olivaceus) were investigated using CD4-1 pAbs and CD8α pAbs. The results showed that CD4-1 molecule ORF was 1413 bp and CD8α was 690 bp, both molecules are transmembrane glycoproteins with high amino acid homology to grouper. The CD4-1 pAbs specifically recognized both the CD4-1 recombinant and natural proteins, as does the CD8α pAbs to CD8α molecule, and no cross-reactivity between the two antibodies. CD4-1 and CD8α T lymphocytes were detected in peripheral blood, spleen and head kidney leukocytes in spotted sea bass. In cross-reactivity assay with other three fish, CD4-1 pAbs could recognize the lymphocytes from pearl gentian grouper and schlegel's black rockfish, both with highest proportions in the spleen leukocytes, 5.3 ± 0.4% and 2.6 ± 0.3%, respectively, and CD8α pAbs could only recognize the lymphocytes in pearl gentian grouper, and no cross-reactivities to lymphocytes of flounder. These data suggested that the CD4-1 and CD8α molecules varied by fish species in the genes features and antigenicity, which might result in the diversities of T lymphocytes subpopulations. This will be a key to elucidating the classification and evolution of T lymphocytes in fish.
Topics: Animals; Bass; Flounder; Head Kidney; Perciformes; Leukocytes; CD4 Antigens
PubMed: 36210001
DOI: 10.1016/j.fsi.2022.10.004 -
Developmental Biology Jan 2015The respective role of Pax2 and Pax8 in early kidney development in vertebrates is poorly understood. In this report, we have studied the roles of Pax8 and Pax2 in...
The respective role of Pax2 and Pax8 in early kidney development in vertebrates is poorly understood. In this report, we have studied the roles of Pax8 and Pax2 in Xenopus pronephros development using a loss-of-function approach. Our results highlight a differential requirement of these two transcription factors for proper pronephros formation. Pax8 is necessary for the earliest steps of pronephric development and its depletion leads to a complete absence of pronephric tubule. Pax2 is required after the establishment of the tubule pronephric anlage, for the expression of several terminal differentiation markers of the pronephric tubule. Neither Pax2 nor Pax8 is essential to glomus development. We further show that Pax8 controls hnf1b, but not lhx1 and Osr2, expression in the kidney field as soon as the mid-neurula stage. Pax8 is also required for cell proliferation of pronephric precursors in the kidney field. It may exert its action through the wnt/beta-catenin pathway since activation of this pathway can rescue MoPax8 induced proliferation defect and Pax8 regulates expression of the wnt pathway components, dvl1 and sfrp3. Finally, we observed that loss of pronephros in Pax8 morphants correlates with an expanded vascular/blood gene expression domain indicating that Pax8 function is important to delimit the blood/endothelial genes expression domain in the anterior part of the dorso-lateral plate.
Topics: Animals; Bromodeoxyuridine; DNA Primers; Gene Expression Regulation, Developmental; In Situ Hybridization; PAX2 Transcription Factor; PAX8 Transcription Factor; Paired Box Transcription Factors; Polymerase Chain Reaction; Pronephros; Real-Time Polymerase Chain Reaction; Wnt Signaling Pathway; Xenopus; Xenopus Proteins
PubMed: 25446030
DOI: 10.1016/j.ydbio.2014.10.022 -
Fish & Shellfish Immunology Aug 2023CD27 is a member of the TNF-receptor superfamily and plays various roles in immunities. However, the detailed information and mechanism of CD27 in bony fish immunity...
CD27 is a member of the TNF-receptor superfamily and plays various roles in immunities. However, the detailed information and mechanism of CD27 in bony fish immunity remain unclear. Therefore, in this research, certain interesting roles of CD27 in Nile tilapia (On-CD27) were determined. On-CD27 was largely expressed in the immune organs, head kidney, and spleen, and was sharply induced during bacterial infection. The in vitro tests suggested On-CD27 was involved in regulating inflammatory responses, activating immune-related signal pathways, and inducing apoptosis and pyroptosis progress. The scRNA data and in vivo experiments indicated that On-CD27 is mainly expressed in CD4 T cells and involved in both innate and adaptive immunities. The present data provide a theoretical principle for further research on the mechanisms of CD27 in the innate and adaptive immunities of fish.
Topics: Animals; Cichlids; Fish Proteins; Spleen; Streptococcal Infections; Head Kidney; Fish Diseases; Streptococcus agalactiae; Immunity, Innate; Gene Expression Regulation
PubMed: 37394017
DOI: 10.1016/j.fsi.2023.108923 -
Fish & Shellfish Immunology Jan 2018The aim of this study was to compare how different dietary vegetable oil n-6/n-3 ratios affect gene responses involved in inflammation, signaling pathways, fatty acid... (Comparative Study)
Comparative Study
A comparative study: Difference in omega-6/omega-3 balance and saturated fat in diets for Atlantic salmon (Salmo salar) affect immune-, fat metabolism-, oxidative and apoptotic-gene expression, and eicosanoid secretion in head kidney leukocytes.
The aim of this study was to compare how different dietary vegetable oil n-6/n-3 ratios affect gene responses involved in inflammation, signaling pathways, fatty acid synthesis and oxidation, oxidation and apoptosis as well as eicosanoid production in salmon head kidney tissues and isolated head kidney leukocytes. Salmon smolts (200 g) were fed four different diets where the main lipid components were palm oil (n-6/n-3 ratio = 0.7), rapeseed oil (n-6/n-3 ratio = 0.9), and soybean oil (n-6/n-3 ratio = 2.4) and a high soybean oil diet with an n-6/n-3 ratio = 4. Both head kidney tissue and leukocytes isolated from head kidneys were sampled from the four diets, but from different fish. Leukocytes isolated from the head kidneys were seeded into culture wells and added lipopolysaccharide (LPS) to induce inflammatory responses. Controls without LPS were included. Head kidney leukocytes and the tissues should have the same phenotype reflecting the different diets. Interleukin 1β (IL-1β) transcription was elevated in head kidney tissue and especially in LPS treated leukocytes isolated from soybean oil (n-6/n-3 = 2.4) fed salmon, which confirmed the suitability of the in vitro model in this experiment. Leukocytes, treated with LPS, and isolated from salmon fed the soybean oil diet (n-6/n-3 = 2.4) also upregulated tumor necrosis factor alpha (tnf-α), cyclooxygenase (cox2), prostaglandin D and E synthase (ptgds, ptges), fatty acyl synthase (fas), 5 and 6 desaturases (5des, 6 des) and a fatty acid translocase protein (cd36) when compared to the other diets. The results suggest that diets with a specific n-6/n-3 ratio influence the transcription of pro-inflammatory genes and may be cross-linked to transcription of selected fatty acid metabolism genes. Salmon fed the palm oil diet (n-6/n-3 = 0.7) showed a lower expression of inflammatory genes. Instead, peroxisome proliferator activated receptor β1 (pparβ1), acyl coenzyme A (aco), apoptosis regulator (bax) and superoxide dismutase (sod) were upregulated in leukocytes in vitro, while head kidney tissue transcription of a dendritic marker (cd83) was lower than measured in tissues from fish fed the other diets. The concentration of LTB4 (10-20 ng/mL) were relatively constant in leukocyte supernatants, all diets. Head kidney leukocytes from soybean oil (n-6/n-3 = 2.4) fed fish produced LPS induced PGE2 (mean 0.5 ng/mL) while leukocytes isolated from palm oil diet (n-6/n-3 = 0.7) secreted very high amounts of LTB5 (50-70 ng/mL). In addition, equal amounts of LPS induced PGE2 and PGE3 (mean 0, 5 ng/mL) were produced, indicating that the n-6/n-3 ratio of this saturated fatty acid may have a specific impact on eicosanoid production in the head kidney of salmon.
Topics: Animals; Apoptosis; Dietary Fats; Eicosanoids; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Gene Expression Regulation; Head Kidney; Immunity, Innate; Leukocytes; Oxidative Stress; Salmo salar
PubMed: 29080687
DOI: 10.1016/j.fsi.2017.10.040 -
Fish & Shellfish Immunology Nov 2020Oncorhynchus kisutch is the third most cultivated salmonid species in the Chilean salmon industry and its farming conditions are characterised by high stocking density...
Oncorhynchus kisutch is the third most cultivated salmonid species in the Chilean salmon industry and its farming conditions are characterised by high stocking density leading to the generation of high levels of organic matter (food - feces) and decomposition. In addition to the increasingly frequent hypoxic oceanographic events, these inappropriate farming conditions increase the demand for oxygen within the fish farm pen and lead to the appearance of hypoxic events that are harmful to fish.This study aimed to evaluate the stress response (cortisol) and transcription of genes involved in the immune response in head kidney and spleen of Oncorhynchus kisutch subjected to chronic hypoxic stress conditions. The fish were exposed to 100%, 60%, 50%, 35%, and 25% of DO for 28 days, then the blood (plasma), head kidney and spleen were removed. We observed mortality in the 25% DO group at days 15 and 20. Plasma cortisol increased significantly under 35% and 25% DO conditions compared to control. Transcription of Toll-like receptors (TLR1, TLR5M, TLR8, and TLR9) and cytokines (IL-1β, IL6, IL10, TNF-α) increased in the head kidney only in the 50% DO group, while in spleen there was an increase of these markers in the conditions of 60%, 35%, and 25% DO. As for the markers involved in cell-mediated immunity, CD4-MHCII and CD8-MHCI do not have a clear expression pattern, although there was down-regulation in MHCII transcription in the head kidney, in all the hypoxia conditions evaluated. Finally, IgM transcription was increased in the spleen in all hypoxia conditions, although it wasn't always statistically significant compared to the control. These results indicate that chronic hypoxia induces the stress response, increasing plasma cortisol levels and modulating the transcription of genes involved in the innate and adaptive immune response. The expression patterns were tissue-specific, indicating that the degree of hypoxia differentially affects the transcription of genes involved in the immune response of Oncorhynchus kisutch.
Topics: Adaptive Immunity; Anaerobiosis; Animals; Cytokines; Fish Proteins; Head Kidney; Hydrocortisone; Immunity, Innate; Oncorhynchus kisutch; Oxygen; Spleen; Toll-Like Receptors
PubMed: 32950678
DOI: 10.1016/j.fsi.2020.09.025 -
Gene Expression Patterns : GEP Nov 2014The kidney is comprised of nephrons - epithelial tubes with specialized segments that reabsorb and secrete solutes, perform osmoregulation, and produce urine. Different...
The kidney is comprised of nephrons - epithelial tubes with specialized segments that reabsorb and secrete solutes, perform osmoregulation, and produce urine. Different nephron segments exhibit unique combinations of ion channels, transporter proteins, and cell junction proteins that govern permeability between neighboring cells. The zebrafish pronephros is a valuable model to study the mechanisms of vertebrate nephrogenesis, but many basic features of segment gene expression in renal progenitors and mature nephrons have not been characterized. Here, we analyzed the temporal and spatial expression pattern of tight junction components during zebrafish kidney ontogeny. During nephrogenesis, renal progenitors show discrete expression domains of claudin (cldn) 15a, cldn8, occludin (ocln) a, oclnb, tight junction protein (tjp) 2a, tjp2b, and tjp3. Interestingly, transcripts encoding these genes exhibit dynamic spatiotemporal domains during the time when pronephros segment domains are established. These data provide a useful gene expression map of cell junction components during zebrafish nephrogenesis. As such, this information complements the existing molecular map of nephron segment characteristics, and can be used to characterize kidney development mutants as well as various disease models, in addition to aiding in the elucidation of mechanisms governing epithelial regeneration after acute nephron injury.
Topics: Animals; Gene Expression Regulation, Developmental; In Situ Hybridization; Nephrons; Organogenesis; Pronephros; Tight Junctions; Transcription, Genetic; Zebrafish; Zebrafish Proteins
PubMed: 25460834
DOI: 10.1016/j.gep.2014.11.001 -
Fish & Shellfish Immunology Jun 2017This study was conducted to investigate the effects of dietary iron on the growth, and immune function and structural integrity in head kidney, spleen and skin as well...
The decreased growth performance and impaired immune function and structural integrity by dietary iron deficiency or excess are associated with TOR, NF-κB, p38MAPK, Nrf2 and MLCK signaling in head kidney, spleen and skin of grass carp (Ctenopharyngodon idella).
This study was conducted to investigate the effects of dietary iron on the growth, and immune function and structural integrity in head kidney, spleen and skin as well as the underlying signaling of young grass carp (Ctenopharyngodon idella). Total 630 grass carp (242.32 ± 0.58 g) were fed diets containing graded levels of iron at 12.15 (basal diet), 35.38, 63.47, 86.43, 111.09, 136.37 mg/kg (diets 2-6 were added with ferrous fumarate) and 73.50 mg/kg (diet 7 was added with ferrous sulfate) diet for 60 days. Then, a challenge test was conducted by infection of Aeromonas hydrophila for 14 days. The results firstly showed that compared with optimal iron level, iron deficiency decreased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and down-regulated the mRNA levels of antibacterial peptides, anti-inflammatory cytokines, inhibitor of κBα (IκBα), target of rapamycin (TOR) and ribosomal protein S6 kinase 1 (S6K1), whereas up-regulated the mRNA levels of pro-inflammatory cytokines, nuclear factor kappa B (NF-κB) p65, IκB kinases β (IKKβ) and eIF4E-binding protein (4E-BP) in head kidney and spleen of young grass carp (P < 0.05), indicating that iron deficiency impaired immune function in head kidney and spleen of fish. Secondly, iron deficiency down-regulated the mRNA levels of B-cell lymphoma-2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), and inhibitor of apoptosis protein (IAP), and decreased activities and mRNA levels of antioxidant enzymes, down-regulated the mRNA levels of NF-E2-related factor 2 (Nrf2) and tight junction complexes, and up-regulated mRNA levels of cysteinyl aspartic acid-protease (caspase) -2, -3, -7, -8, -9, apoptotic protease activating factor-1 (Apaf-1), Bcl-2 associated X protein (Bax), Fas ligand (FasL), p38 mitogen-activated protein kinase (p38MAPK), Kelch-like ECH-associating protein (Keap) 1a, Keap1b, claudin-12 and myosin light chain kinase (MLCK), and increased malondialdehyde (MDA), protein carbonyl (PC) and reactive oxygen species (ROS) contents in head kidney and spleen of young grass carp (P < 0.05), indicating that iron deficiency impaired structural integrity in head kidney and spleen of fish. Thirdly, iron deficiency increased skin hemorrhage and lesion morbidity, and impaired immune function and structural integrity in skin of fish. Fourthly, iron excess decreased growth and impaired the immune function and structural integrity in head kidney, spleen and skin of fish. Besides, in young grass carp, based on PWG and ability against skin hemorrhage and lesion, the efficacy of ferrous fumarate relative to ferrous sulfate was 140.32% and 126.48%, respectively, and the iron requirements based on PWG, ability against skin hemorrhage and lesion, ACP activities and MDA contents in head kidney and spleen were estimated to be 75.65, 87.03, 79.74, 78.93, 83.17 and 82.14 mg/kg diet (based on ferrous fumarate), respectively.
Topics: Aeromonas hydrophila; Animal Feed; Animals; Carps; Diet; Dose-Response Relationship, Drug; Fish Diseases; Fish Proteins; Gram-Negative Bacterial Infections; Head Kidney; Immunity, Innate; Iron; Iron Deficiencies; Iron, Dietary; Random Allocation; Signal Transduction; Skin; Spleen
PubMed: 28428059
DOI: 10.1016/j.fsi.2017.04.009 -
Tissue & Cell Dec 2020Immune components were investigated in peripheral blood and in spleen and head kidney of autotriploid Salmo trutta f. lacustris, Salvelinus fontinalis, and Salvelinus...
Immune components were investigated in peripheral blood and in spleen and head kidney of autotriploid Salmo trutta f. lacustris, Salvelinus fontinalis, and Salvelinus umbla, and of allotriploid hybrids of S. trutta f. lacustris x Onchorynchus mykiss and S. fontinalis x O. mykiss in comparison to their diploid parents. In peripheral blood the number of lymphocytes was reduced in all investigated autotriploids and in the allotriploid S. trutta f. lacustris x O.mykiss, and the numbers of thrombocytes in autotriploid S. trutta f. lacustris and in both allotriploids. Alternative pathway of complement activity and immunoglobulin concentration were significantly decreased in all investigated auto- and allotriploids, lysozyme activity in autotriploid S. fontinalis and in both allotriploids. In the spleen of the 3 autotriploids the number of erythrocytes was increased, while the number of lymphoid precursor cells was decreased. In their head kidney the erythrocytes numbers were decreased and the numbers of erythropoietic precursor cells and the melanomacrophage centers were increased. Contrary, cytology of spleen and head kidney of the two allotriploid hybrids was similar to diploid controls. Caspase 1, caspase 6, lysozyme, and acid phosphatase activity and immunoglobulin concentration of spleen and head kidney showed specific changes which were related to cytological results. These data indicate alterations in immune system and in lymphoid organs of auto- and allotriploid Salmonidae.
Topics: Adaptive Immunity; Animals; Body Weight; Diploidy; Head Kidney; Hybridization, Genetic; Salmonidae; Spleen; Tetraploidy
PubMed: 33099197
DOI: 10.1016/j.tice.2020.101445