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Frontiers in Immunology 2021is a Gram-positive, intracellular pathogen that causes Bacterial Kidney Disease (BKD) in several fish species in freshwater and seawater. Lumpfish () is utilized as a...
is a Gram-positive, intracellular pathogen that causes Bacterial Kidney Disease (BKD) in several fish species in freshwater and seawater. Lumpfish () is utilized as a cleaner fish to biocontrol sea lice infestation in Atlantic salmon () farms. Atlantic salmon is susceptible to , and it can transfer the infection to other fish species. Although BKD outbreaks have not been reported in lumpfish, its susceptibility and immune response to is unknown. In this study, we evaluated the susceptibility and immune response of lumpfish to infection. Groups of lumpfish were intraperitoneally (i.p.) injected with either (1×10, 1×10, or 1×10 cells dose) or PBS (control). infection kinetics and mortality were followed for 98 days post-infection (dpi). Transcript expression levels of 33 immune-relevant genes were measured in head kidney ( = 6) of fish infected with 1×10 cells/dose and compared to the control at 28 and 98 dpi. Infected lumpfish displayed characteristic clinical signs of BKD. Lumpfish infected with high, medium, and low doses had a survival rate of 65%, 93%, and 95%, respectively. Mortality in the high-dose infected group stabilized after 50 dpi, but persisted in the fish tissues until 98 dpi. Cytokines (, , ), pattern recognition receptors (), interferon-induced effectors (, , ), and iron regulation () and acute phase reactant () related genes were up-regulated at 28 dpi. In contrast, cell-mediated adaptive immunity-related genes (, , , , ) were down-regulated at 28 dpi, revealing the immune suppressive nature of . However, significant upregulation of at 98 dpi suggests induction of cell-mediated immune response. This study showed that infected lumpfish in a similar fashion to salmonid fish species and caused a chronic infection, enhancing cell-mediated adaptive immune response.
Topics: Adaptive Immunity; Animals; Bacterial Load; Bacteriological Techniques; Chronic Disease; Disease Susceptibility; Fish Diseases; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Gene Ontology; Gram-Positive Bacterial Infections; Head Kidney; Host-Pathogen Interactions; Immunity, Cellular; Kidney Diseases; Perciformes; Real-Time Polymerase Chain Reaction; Renibacterium; Species Specificity; Specific Pathogen-Free Organisms
PubMed: 34880856
DOI: 10.3389/fimmu.2021.733266 -
Cellular and Molecular Life Sciences :... May 2024Trimeric G proteins transduce signals from a superfamily of receptors and each G protein controls a wide range of cellular and systemic functions. Their highly conserved...
Trimeric G proteins transduce signals from a superfamily of receptors and each G protein controls a wide range of cellular and systemic functions. Their highly conserved alpha subunits fall in five classes, four of which have been well investigated (Gs, Gi, G12, Gq). In contrast, the function of the fifth class, Gv is completely unknown, despite its broad occurrence and evolutionary ancient origin (older than metazoans). Here we show a dynamic presence of Gv mRNA in several organs during early development of zebrafish, including the hatching gland, the pronephros and several cartilage anlagen, employing in situ hybridisation. Next, we generated a Gv frameshift mutation in zebrafish and observed distinct phenotypes such as reduced oviposition, premature hatching and craniofacial abnormalities in bone and cartilage of larval zebrafish. These phenotypes could suggest a disturbance in ionic homeostasis as a common denominator. Indeed, we find reduced levels of calcium, magnesium and potassium in the larvae and changes in expression levels of the sodium potassium pump atp1a1a.5 and the sodium/calcium exchanger ncx1b in larvae and in the adult kidney, a major osmoregulatory organ. Additionally, expression of sodium chloride cotransporter slc12a3 and the anion exchanger slc26a4 is altered in complementary ways in adult kidney. It appears that Gv may modulate ionic homeostasis in zebrafish during development and in adults. Our results constitute the first insight into the function of the fifth class of G alpha proteins.
Topics: Animals; Zebrafish; Homeostasis; Zebrafish Proteins; GTP-Binding Protein alpha Subunits; Larva; Gene Expression Regulation, Developmental; Sodium-Potassium-Exchanging ATPase; Calcium; Kidney; Magnesium
PubMed: 38727814
DOI: 10.1007/s00018-024-05228-w -
International Journal of Molecular... Sep 2022is a bacterial pathogen causing winter-ulcer disease in Atlantic salmon. The lesions on affected fish lead to increased mortality, decreased fish welfare, and inferior...
is a bacterial pathogen causing winter-ulcer disease in Atlantic salmon. The lesions on affected fish lead to increased mortality, decreased fish welfare, and inferior meat quality in farmed salmon. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional regulation by guiding the miRNA-induced silencing complex to specific mRNA transcripts (target genes). The goal of this study was to identify miRNAs responding to in salmon by investigating miRNA expression in the head-kidney and the muscle/skin from lesion sites caused by the pathogen. Protein coding gene expression was investigated by microarray analysis in the same materials. Seventeen differentially expressed guide-miRNAs (gDE-miRNAs) were identified in the head-kidney, and thirty-nine in lesion sites, while the microarray analysis reproduced the differential expression signature of several thousand genes known as infection-responsive. In silico target prediction and enrichment analysis suggested that the gDE-miRNAs were predicted to target genes involved in immune responses, hemostasis, angiogenesis, stress responses, metabolism, cell growth, and apoptosis. The majority of the conserved gDE-miRNAs (e.g., miR-125, miR-132, miR-146, miR-152, miR-155, miR-223 and miR-2188) are known as infection-responsive in other vertebrates. Collectively, the findings indicate that gDE-miRNAs are important post-transcriptional gene regulators of the host response to bacterial infection.
Topics: Animals; Head Kidney; MicroRNAs; Moritella; RNA, Messenger; Salmo salar
PubMed: 36232504
DOI: 10.3390/ijms231911200 -
Zoological Research Jul 2019Hemorrhagic septicemia is an acute, highly fatal disease that affects goldfish (). To gain a better understanding of related immune genes, the transcriptomes of the skin...
Hemorrhagic septicemia is an acute, highly fatal disease that affects goldfish (). To gain a better understanding of related immune genes, the transcriptomes of the skin and head kidney of goldfish suffering hemorrhagic septicemia were sequenced, assembled, and characterized. Based on functional annotation, an extensive and diverse catalog of expressed genes were identified in both the skin and head kidney. As two different organs, pair-wise comparison identified 122/77 unigenes up/down-regulated (two-fold change with <0.05) in the skin and head kidney. Most genes of the immune pathways were expressed and isolated in both skin and head kidney, including interferon (IFN) transcription factors 1-10 and Toll-like receptors (TLRs). Interferon regulatory factor 3 (IRF3), a key IFN transcription factor, was up-regulated at the transcriptional level by polyriboinosinic: polyribocytidylic acid (poly I:C) challenge and regulated the IFN response by increasing the activity of IFN-β and IFN-stimulated response element (ISRE)-containing promoter. This study will benefit the identification and understanding of novel genes that play important roles in the immunological reactions of fish suffering from hemorrhagic septicemia.
Topics: Animals; Fish Diseases; Goldfish; Head Kidney; Hemorrhagic Septicemia; Poly I-C; Skin; Transcriptome
PubMed: 31033261
DOI: 10.24272/j.issn.2095-8137.2019.028 -
Development (Cambridge, England) Sep 2023Vertebrate podocytes and Drosophila nephrocytes display slit diaphragms, specialised cell junctions that are essential for the execution of the basic excretory function...
Vertebrate podocytes and Drosophila nephrocytes display slit diaphragms, specialised cell junctions that are essential for the execution of the basic excretory function of ultrafiltration. To elucidate the mechanisms of slit diaphragm assembly we have studied their formation in Drosophila embryonic garland nephrocytes. These cells of mesenchymal origin lack overt apical-basal polarity. We find that their initial membrane symmetry is broken by an acytokinetic cell division that generates PIP2-enriched domains at their equator. The PIP2-enriched equatorial cortex becomes a favourable domain for hosting slit diaphragm proteins and the assembly of the first slit diaphragms. Indeed, when this division is either prevented or forced to complete cytokinesis, the formation of diaphragms is delayed to larval stages. Furthermore, although apical polarity determinants also accumulate at the equatorial cortex, they do not appear to participate in the recruitment of slit diaphragm proteins. The mechanisms we describe allow the acquisition of functional nephrocytes in embryos, which may confer on them a biological advantage similar to the formation of the first vertebrate kidney, the pronephros.
Topics: Animals; Drosophila; Cell Division; Cytokinesis; Cerebral Cortex; Diaphragm
PubMed: 37681291
DOI: 10.1242/dev.201708 -
Kidney International Jun 2020Inherited and acquired disorders that affect proximal tubule endocytosis and lysosomal processing manifest with improper loss of solutes and proteins. The zebrafish...
Inherited and acquired disorders that affect proximal tubule endocytosis and lysosomal processing manifest with improper loss of solutes and proteins. The zebrafish pronephros is conserved with humans and is used to model numerous renal conditions, but has few quantitative measures for proximal tubule function. Here, Chen et al. developed a high-throughput assay to quantify proteinuria and lysosomal processing in transgenic zebrafish by labeling vitamin D protein, allowing for precise reporting of proximal tubule function.
Topics: Animals; Fanconi Syndrome; Humans; Kidney; Kidney Tubules, Proximal; Pronephros; Zebrafish
PubMed: 32444088
DOI: 10.1016/j.kint.2020.02.014 -
Frontiers in Immunology 2021The mechanisms underlying -induced mycobacteriosis remain unexplored. Using head kidney macrophages (HKM) from catfish (), we report that Ca surge across...
The mechanisms underlying -induced mycobacteriosis remain unexplored. Using head kidney macrophages (HKM) from catfish (), we report that Ca surge across mitochondrial-Ca uniporter (MICU), and consequent mitochondrial ROS (mtROS) production, is imperative for mycobactericidal activity. Inhibition of mtROS alleviated HKM apoptosis and enhanced bacterial survival. Based on RNA interference (RNAi) and inhibitor studies, we demonstrate that the Toll-like receptor (TLR)-2-endoplasmic reticulum (ER) stress-store-operated calcium entry (SOCE) axis is instrumental for activating the mt-Ca/mtROS cascade in -infected HKM. Additionally, pharmacological inhibition of mtROS attenuated the expression of , , and , which suggests a positive feedback loop between ER-stress-induced SOCE and mtROS production. Elevated tumor necrosis factor alpha (TNF-α) levels and caspase-8 activity were observed in HKM consequent to infection, and our results implicate that mtROS is crucial in activating the TNF-mediated caspase-8 activation. Our results for the first time demonstrate mitochondria as an innate immune signaling center regulating mycobacteriosis in fish. We conclude that induced persistent SOCE signaling leads to mtROS production, which in turn activates the TNF-α/caspase-8 axis culminating in HKM apoptosis and bacterial clearance.
Topics: Animals; Calcium; Catfishes; Head Kidney; Macrophages; Mitochondria; Mycobacterium Infections, Nontuberculous; Mycobacterium fortuitum; Reactive Oxygen Species; Signal Transduction; Toll-Like Receptor 2
PubMed: 34987503
DOI: 10.3389/fimmu.2021.748758 -
Innate Immunity Jul 2020Innate immunity is the first line of defense against pathogen infections. Extracellular ATP (eATP) is one of the most studied danger-associated molecular pattern...
Innate immunity is the first line of defense against pathogen infections. Extracellular ATP (eATP) is one of the most studied danger-associated molecular pattern molecules that can activate host innate immune responses through binding with and activating purinergic receptors on the plasma membrane. The detailed actions of eATP on fish innate immunity, however, remain poorly understood. In this study, we investigated bacterial pathogen-induced ATP release in head kidney cells of the Japanese flounder . We also examined the actions of eATP on pro-inflammatory cytokine and immune-related gene expression, the activity of induced NO synthase (iNOS), and the production of reactive oxygen species (ROS) and NO in Japanese flounder immune cells. We demonstrate that ATP is dynamically released from Japanese flounder head kidney cells into the extracellular milieu during immune challenge by formalin-inactivated and . In addition, we show that eATP administration results in profound up-regulation of pro-inflammatory cytokine gene expression, iNOS activity, and inflammatory mediator production, including ROS and NO, in Japanese flounder immune cells. Altogether, our findings demonstrate that eATP is a potent signaling molecule for the activation of innate immune responses in fish.
Topics: Adenosine Triphosphate; Animals; Antigens, Bacterial; Cells, Cultured; Cytokines; Edwardsiella tarda; Enterobacteriaceae Infections; Extracellular Space; Fish Proteins; Flounder; Head Kidney; Immunity, Innate; Inflammation Mediators; Nitric Oxide Synthase Type II; Signal Transduction; Up-Regulation; Vibrio; Vibrio Infections
PubMed: 31914841
DOI: 10.1177/1753425918804635 -
Fish & Shellfish Immunology Mar 2020The functional spectrum of the teleostean head kidney covers haematopoietic, immune and endocrine signalling pathways with physiological effects that are likely to...
The functional spectrum of the teleostean head kidney covers haematopoietic, immune and endocrine signalling pathways with physiological effects that are likely to conflict if activated at the same time. An in vivo experiment on the salmonid fish maraena whitefish (Coregonus maraena) revealed that the head kidney shows a remarkably strong response after injection of Aeromonas salmonicida within 48 h. In order to investigate the potential influence of endocrine signalling on the initiation of immune responses, we established a primary culture of head-kidney cells of maraena whitefish. For the characterisation of this model system, we used flow cytometry complemented with an extensive panel of immunological/haematological and stress-physiological/neuroendocrinological qPCR assays. More than one third of the cells expressed the characteristic signature of myeloid cells, while more than half of the cells expressed those genes typical for lymphocytes and monocytes. In parallel, we quantified the expression of genes encoding endocrine receptors and identified ADRA2D as by far the most highly expressed adrenergic-receptor gene in head-kidney cells. The stimulation of the head-kidney cells with toll-like receptor ligands induced the expression of typical immune genes (IL1B, CXCL8, TNF, SAA) after only 1 h. The incubation with the stress hormones cortisol, adrenaline and noradrenaline also had an immune-activating effect, though less pronounced. However, cortisol had the strongest suppressive effect on the stimulation-induced immune response, while adrenaline exerted a comparably weaker effect and noradrenaline was almost ineffective. Moreover, we found that cortisol reduced the expression of genes coding for adrenergic and some glucocorticoid receptors, while noradrenaline increased it. In conclusion, the primary head-kidney cells of maraena whitefish reflect the immunological and neuroendocrinological diversity of the entire organ. This in vitro system allowed thus identifying the correlative changes between the activities of hormones and immune factors in salmonid fish in order to contribute to a better understanding of the regulation circuit between stress and immune defence.
Topics: Aeromonas salmonicida; Animals; Cells, Cultured; Epinephrine; Fish Diseases; Fish Proteins; Gram-Negative Bacterial Infections; Head Kidney; Hydrocortisone; Immunity, Innate; Ligands; Norepinephrine; Pathogen-Associated Molecular Pattern Molecules; Salmonidae; Toll-Like Receptors; Transcriptome
PubMed: 31770645
DOI: 10.1016/j.fsi.2019.11.058 -
International Journal of Molecular... Aug 2020The arylhydrocarbon receptor (AhR) is an important signaling pathway in the immune system of mammals. In addition to its physiological functions, the receptor mediates...
The arylhydrocarbon receptor (AhR) is an important signaling pathway in the immune system of mammals. In addition to its physiological functions, the receptor mediates the immunotoxic actions of a diverse range of environmental contaminants that bind to and activate the AhR, including planar halogenated aromatic hydrocarbons (PHAHs or dioxin-like compounds) and polynuclear aromatic hydrocarbons (PAHs). AhR-binding xenobiotics are immunotoxic not only to mammals but to teleost fish as well. To date, however, it is unknown if the AhR pathway is active in the immune system of fish and thus may act as molecular initiating event in the immunotoxicity of AhR-binding xenobiotics to fish. The present study aims to examine the presence of functional AhR signaling in immune cells of rainbow trout (). Focus is given to the toxicologically relevant AhR2 clade. By means of RT-qPCR and in situ hybdridization, we show that immune cells of rainbow trout express and mRNA; this applies for immune cells isolated from the head kidney and from the peripheral blood. Furthermore, we show that in vivo as well as in vitro exposure to the AhR ligand, benzo(a)pyrene (BaP), causes upregulation of the AhR-regulated gene, , in rainbow trout immune cells, and that this induction is inhibited by co-treatment with an AhR antagonist. Taken together, these findings provide evidence that functional AhR signaling exists in the immune cells of the teleost species, rainbow trout.
Topics: Animals; Cytochrome P-450 CYP1A1; Fish Proteins; Head Kidney; Lymphocytes; Neutrophils; Oncorhynchus mykiss; Receptors, Aryl Hydrocarbon
PubMed: 32878328
DOI: 10.3390/ijms21176323