Inflammation In Zebrafish Research Articles

Developmental defects and behavioral changes in a diet-induced inflammation model of zebrafish

Soybean meal evokes diet-induced intestinal inflammation in certain fishes. Although the molecular aspects of soybean-induced intestinal inflammation in zebrafish are known, the impact of the inflammatory diet on fish behavior remain largely underexplored. We fed zebrafish larvae with three diets - control, soybean meal and soybean meal with β-glucan to gain deeper insight into the behavioral changes associated with the soybean meal-induced inflammation model. We assessed the effect of the diets on the locomotor behavior, morphological development, oxygen consumption and larval transcriptome. Our study revealed that dietary soybean meal can reduce the locomotor activity, induce developmental defects and increase the oxygen demand in zebrafish larvae. Transcriptomic analysis pointed to the suppression of genes linked to visual perception, organ development, phototransduction pathway and activation of genes linked to the steroid biosynthesis pathway. On the contrary, β-glucan, an anti-inflammatory feed additive, counteracted the behavioral and phenotypic changes linked to dietary soybean. Although we did not identify any differentially expressed genes from the soybean meal alone fed group vs soybean meal + β-glucan-fed group comparison, the unique genes from the comparisons of the two groups with the control likely indicate reduction in inflammatory cytokine signaling, inhibition of proteolysis and induction of epigenetic modifications by the dietary glucan. Furthermore, we found that feeding an inflammatory diet at the larval stage can lead to long-lasting developmental defects. In conclusion, our study reveals the extra-intestinal manifestations associated with soybean meal-induced inflammation model.

Anti-inflammatory and immunostimulant effect of different timing-related administration of dietary polyphenols on intestinal inflammation in zebrafish, Danio rerio

A short-term study was performed to assess the effects of diets supplemented with polyphenols (CSVP), extracted from the chestnut (Castanea sativa) shell, agri-food waste rich in tannins, and mullein (Verbascum macrurum), a perennial spontaneous plant rich in flavonoids, on a zebrafish (Danio rerio) model of k-carrageenan-induced intestinal inflammation. Morphological asset of intestine, immunodensity of the pro-inflammatory mediator Tumor necrosis factor α (TNFα) and Cyclooxygenase-2 (COX-2), immunoexpression of the two antioxidant enzymes Catalase (Cat) and Superoxide dismutase 2 (Sod2), quantitative gene expression of pro- and anti-inflammatory cytokines including TNFα, COX2A, Interleukin-1β (IL-1β) and IL-10, and the activated cell pathways were analyzed. Seven experimental diets were formulated including: peeled A. salina (Control group), peeled A. salina + 0.1% of k-carrageenan (Inflamed group), peeled A. salina + CSVP followed by k-carrageenan inflammatory diet (CSVP pre-treated group), peeled A. salina + 0.1% of k-carrageenan + CSVP (CSVP co-treated group), peeled A. salina + 0.1% of k-carrageenan followed by CSVP (CSVP post-treated group), peeled A. salina + CSVP (CSVP group) and peeled A. salina + 0.1% of k-carrageenan followed by 10 days of control diet (polyphenols control group or CP) to determine the efficacy of schedule administering polyphenols in preventing or ameliorating the intestinal inflammation induced in adult zebrafish by k-carrageenan with mean weight of 400 ± 100 mg (mean ± SD; total n = 250). The obtained results indicated that k-carrageenan caused morphological alterations such as the decrease of intestinal folds with consequent expansion of gut lumen, and increased number of goblet cells, as well as the over-regulation of pro-inflammatory markers and reduction of the antioxidant enzymes immunoexpression. Polyphenols supplementation ameliorated the inflammatory status, downregulated the pro-inflammatory markers, and upregulated IL-10, the main anti-inflammatory cytokine, and antioxidant activity when administered before the inflammation caused by k-carrageenan. The post- and co-treatment reverted only in part the morphological and physiological alterations. Moreover, the results showed that polyphenols modulated the anti-inflammatory effects acting on the Mitogen-activated protein kinase (MAPK) pathway, by inhibiting p38 phosphorylation and increasing extracellular-signal-regulated kinase (ERK) activation, which subsequently led to suppression of nuclear factor kappa B cells (NF-kB) pathway. Based on the findings achieved, the scheduled administration of bioactive phytochemicals like polyphenols could represent a suitable strategy for ameliorating intestinal inflammation in zebrafish and could be considered as a beneficial and sustainable feed additive in the aquaculture sector.

Pumpkin Skin Polysaccharide-Zn(II) Complex: Preparation, Characterization, and Suppression of Inflammation in Zebrafish.

In this study, pumpkin (Cucurbita moschata) skin polysaccharide–zinc(II) (PSP−Zn) complex was successfully prepared. The structure and physicochemical properties of PSP and PSP−Zn were analyzed. The anti-inflammatory activity of PSP and PSP−Zn was investigated in zebrafish larvae induced by copper sulphate. PSP and PSP−Zn consisted of rhamnose, arabinose, galactose, glucose, and galacturonic acid. The molecular weight (Mw) of PSP and PSP−Zn were 3.034 × 106 and 3.222 × 106 Da, respectively. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) analysis results suggested that the chemical modification of zinc might occur through hydroxyl groups of PSP. The PSP−Zn complex had lamellar texture, smooth surface morphology, and larger particle size. X-ray Diffraction (XRD) analysis revealed that both PSP and PSP−Zn were semi-crystalline substances. PSP−Zn solution showed superior stability in a weak acid and alkaline environment, especially at pH = 6.0. Moreover, PSP and PSP−Zn showed a good inhibitory effect on inflammation cells in zebrafish. Real-time quantitative polymerase chain reaction (RT-PCR) result suggested that the anti-inflammatory mechanism of PSP and PSP−Zn were through downregulation of the expression of nitric oxide synthase 2b (nos2b), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and nuclear factor-kappa B2 (NF-κB2). The present study indicated that PSP−Zn is expected to be a safe and efficient novel zinc supplement with anti-inflammatory activity.

Oxyfluorfen exposure can cause acute kidney injury by promoting ROS-induced oxidative stress and inflammation in zebrafish

Nephrotoxicity of oxyfluorfen to vertebrates remains unclear despite its wide use as a herbicide. In order to further study its nephrotoxicity and its underlying mechanism, we used human embryonic kidney cells and zebrafish to explore. HEK293T cells were exposed to 2, 4, 6 μg/mL oxyfluorfen for 24 h in vitro, and zebrafish were exposed to 0.4, 0.8, 1.2 mg/L oxyfluorfen for 72 h in vivo. We found that oxyfluorfen inhibits cell migration and induces oxidative stress and apoptosis, causing kidney damage or nephrotoxicity in embryonic and adult zebrafish. Oxyfluorfen triggered inflammation in zebrafish and causing severe periorbital and body edema in embryos. Oxyfluorfen induced the secretion of kidney injury markers, including urea nitrogen (BUN), creatinine (CR), and β-n-acetyl-glucosaminidase (NAG) in zebrafish. Additionally, oxyfluorfen affected the homeostasis of oxidant and antioxidant systems, leading to reactive oxygen species (ROS) overload. Oxyfluorfen also damaged the glomerular podocytes and induced apoptosis of proximal tubules, which is harmful to normal body function and the renal filtration system. These results indicate that oxyfluorfen is a potential environmental hazard that can cause severe kidney injury and affect the health of organisms.

Daidzein normalized gentamicin-induced nephrotoxicity and associated pro-inflammatory cytokines in MDCK and zebrafish: Possible mechanism of nephroprotection

This study investigates the therapeutic activity of daidzein, an isoflavone that occurs naturally in plants and herbs, against gentamicin-induced nephrotoxicity in Madin-Darby canine kidney (MDCK) cells in-vitro and zebrafish model in-vivo. The in-vitro studies revealed that daidzein protected MDCK cells from gentamicin-induced inflammation by suppressing oxidative stress and apoptosis. The zebrafish were divided into groups and injected with gentamicin (140 mg/mL) to induce nephrotoxic conditions. After injection, renal dysfunction, nitric oxide production, antioxidant consumption, exaggerated apoptosis, and inflammation were all observed in the zebrafish model. We also observed that during kidney inflammation in zebrafish, pro-inflammatory cytokines such as cyclooxygenase (COX-2), tumor necrosis factor (TNF-α), and interleukin-1β (IL-1β) are upregulated. Furthermore, daidzein treatment after gentamicin injection showed a strong protective anti-inflammatory effect. Daidzein activity was associated with an increase in antioxidant biomarkers such as superoxide dismutase (SOD) and glutathione reductase (GSH), whereas lipid peroxidation (LPO) and nitric oxide (NO) production were decreased in a dose-dependent factor. Moreover, histopathological alteration caused by gentamicin in zebrafish kidneys was normalized due to daidzein treatment. Daidzein also downregulated the pro-inflammatory cytokines gene expression in gentamicin-induced kidney inflammation in zebrafish. These results revealed that daidzein could potentially prevent nephrotoxic conditions through pro-inflammatory cytokines inhibition and its antioxidant property.

Genetically inducible and reversible zebrafish model of systemic inflammation.

ABSTRACTThe inflammatory response is a vital defense mechanism against trauma and pathogen induced damage, but equally important is its appropriate resolution. In some instances of severe trauma or sustained infection, inappropriate and persistent activation of the immune response can occur, resulting in a dangerous systemic inflammatory response. Untreated, this systemic inflammatory response can lead to tissue damage, organ shutdown, and death. Replicating this condition in tractable model organisms can provide insight into the mechanisms involved in the induction, maintenance, and resolution of inflammation. To that end, we developed a non-invasive, inducible, and reversible model of systemic inflammation in zebrafish. Using the Gal4-EcR/UAS system activated by the ecdysone analog tebufenozide, we generated transgenic zebrafish that allow for chemically induced, ubiquitous secretion of the mature form of zebrafish interleukin-1β (Il-1βmat) in both larval and adult developmental stages. To ensure a robust immune response, we attached a strong signal peptide from the Gaussia princeps luciferase enzyme to promote active secretion of the cytokine. We observe a dose-dependent inflammatory response involving neutrophil expansion accompanied by tissue damage and reduced survival. Washout of tebufenozide permits inflammation resolution. We also establish the utility of this model for the identification of small molecule anti-inflammatory compounds by treatment with the immunosuppressant rapamycin. Taken together, these features make this model a valuable new tool that can aid in identifying potential new therapies while broadening our understanding of systemic inflammation, its impact on the immune system, and its resolution.

Organometallic Folate Gold Nanoparticles Ameliorate Lipopolysaccharide-Induced Oxidative Damage and Inflammation in Zebrafish Brain.

Synthesized organometallic gold-based folate nanoparticles (FAuNPs) were characterized, and its defense against lipopolysaccharide (LPS)-induced brain inflammation in Zebra fish was proven. Vitamin entrapment efficiency of these particles was found to be nearly 70%. The in vitro pH-dependent drug release dialysis study of FAuNPs confirmed a slow, sustained, and gradual release of folate for a period of 24 h. Both AuNPs and FAuNPs did not cause any marked changes in food intake, body weight, color, behavioral pattern, blood parameters, and hepatotoxicity. Histology of liver showed no changes between treated and control groups of fishes. The ex vivo study showed significant uptake of FAuNPs to free folate in folate receptor negative Hek293 cells, confirming a strategy to overcome folate deficiency in the brain. Antioxidant status and activities of few crucial brain enzymes were also measured to assess the brain function and found to be returned to the basal level, following FAuNP treatment. The transcription factor NRF2-Keap 1 expression pattern was also noted, and a prominent modulation was observed in the LPS-treated and FAuNP-administered group. Decisive brain enzymes like AChE and Na+K+ATPase were decreased significantly after LPS treatment, which is restored with FAuNP treatment. Caspases increased sharply after LPS treatment and diminished following FAuNP treatment. We conclude that FAuNP due to its high physical stability and uptake could be utilized against severe brain inflammation, leading to brain injury and neurodegeneration.

Chyawanprash, An Ancient Indian Ayurvedic Medicinal Food, Regulates Immune Response in Zebrafish Model of Inflammation by Moderating Inflammatory Biomarkers.

The time-tested Ayurvedic medicinal food, Chyawanprash, has been a part of the Indian diet since ancient times. It is an extremely concentrated mixture of extracts from medicinal herbs and processed minerals, known for its immunity boosting, rejuvenating, and anti-oxidative effects. In this study, we have evaluated the anti-inflammatory potential of Patanjali Special Chyawanprash (PSCP) using the zebrafish model of inflammation. Zebrafish were fed on PSCP-infused pellets at stipulated doses for 13 days before inducing inflammation through lipopolysaccharide (LPS) injection. The test subjects were monitored for inflammatory pathologies like behavioral fever, hyperventilation, skin hemorrhage, locomotory agility, and morphological anomaly. PSCP exerted a strong prophylactic effect on the zebrafish that efficiently protected them from inflammatory manifestations at a human equivalent dose. Expression levels of pro-inflammatory cytokines, like interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin-1 beta (IL-1β), were also reduced in the LPS-stimulated zebrafish fed on PSCP-infused pellets. Skin hemorrhage, hyperventilation, and loss of caudal fins are characteristics of LPS-induced inflammation in zebrafish. PSCP prophylactically ameliorated skin hemorrhage, restored normal respiration, and prevented loss of caudal fin in inflamed zebrafish. Under in vitro conditions, PSCP reduced IL-6 and TNF-α secretion by THP-1 macrophages in a dose-dependent manner by targeting NF-κB signaling, as evident from the secreted embryonic alkaline phosphatase (SEAP) reporter assay. These medicinal benefits of PSCP can be attributed to its constitutional bioactive components. Taken together, these observations provide in vivo validation of the anti-inflammatory property and in vitro insight into the mode-of-action of Chyawanprash, a traditionally described medicinal food.

12-Lipoxygenase governs the innate immune pathogenesis of islet inflammation and autoimmune diabetes.

Macrophages and related myeloid cells are innate immune cells that participate in the early islet inflammation of type 1 diabetes (T1D). The enzyme 12-lipoxygenase (12-LOX) catalyzes the formation of proinflammatory eicosanoids, but its role and mechanisms in myeloid cells in the pathogenesis of islet inflammation have not been elucidated. Leveraging a model of islet inflammation in zebrafish, we show here that macrophages contribute significantly to the loss of β cells and the subsequent development of hyperglycemia. The depletion or inhibition of 12-LOX in this model resulted in reduced macrophage infiltration into islets and the preservation of β cell mass. In NOD mice, the deletion of the gene encoding 12-LOX in the myeloid lineage resulted in reduced insulitis with reductions in proinflammatory macrophages, a suppressed T cell response, preserved β cell mass, and almost complete protection from the development of T1D. 12-LOX depletion caused a defect in myeloid cell migration, a function required for immune surveillance and tissue injury responses. This effect on migration resulted from the loss of the chemokine receptor CXCR3. Transgenic expression of the gene encoding CXCR3 rescued the migratory defect in zebrafish 12-LOX morphants. Taken together, our results reveal a formative role for innate immune cells in the early pathogenesis of T1D and identify 12-LOX as an enzyme required to promote their prodiabetogenic phenotype in the context of autoimmunity.

Congenital Asplenia Interrupts Immune Homeostasis and Leads to Excessive Systemic Inflammation in Zebrafish.

Splenectomy or congenital asplenia in humans increases susceptibility to infections. We have previously reported that congenital asplenia in zebrafish reduces resistance to Aeromonas hydrophila infection. However, the molecular mechanism of systemic immune response in congenitally asplenic individuals is largely unexplored. In this study, we found that pro-inflammatory cytokines were more highly induced in congenitally asplenic zebrafish than wild-type after pathogenic A. hydrophila infection and lipopolysaccharide exposure. In addition, a higher aggregation of apoptotic cells was observed in congenitally asplenic zebrafish than that in wild-type. Next, we examined the transcriptome profiles of whole kidneys from wild-type and congenitally asplenic zebrafish to investigate the effects of congenital asplenia on innate and adaptive immune responses induced by the inactivated A. hydrophila. Congenital asplenia inactivated the splenic anti-inflammatory reflex, disrupted immune homeostasis, and induced excessive inflammation as evidenced by the highly induced stress response–related biological processes, inflammatory and apoptosis-associated pathways, and pro-inflammatory cytokines/chemokines in congenitally asplenic zebrafish compared with wild-type after vaccination. In addition, complement component genes (c3a.1, c3a.6, c4, c6, and c9) and several important immune-related genes (tabp.1, tap1, hamp, prg4b, nfil3, defbl1, psmb9a, tfr1a, and sae1) were downregulated in congenitally asplenic zebrafish. Furthermore, congenital asplenia impaired adaptive immunity as demonstrated by downregulation of biological processes and signaling pathways involved in adaptive immune response after vaccination in congenitally asplenic zebrafish. The expression of MHCII/IgM was also significantly reduced in the congenitally asplenic zebrafish when compared with wild-type. Together, our study provides an in-depth understanding of spleen function in controlling immune homeostasis and may offer insight into the pathological response in splenectomized or congenitally asplenic patients after infections.

Modeling Virus-Induced Inflammation in Zebrafish: A Balance Between Infection Control and Excessive Inflammation.

The inflammatory response to viral infection in humans is a dynamic process with complex cell interactions that are governed by the immune system and influenced by both host and viral factors. Due to this complexity, the relative contributions of the virus and host factors are best studied in vivo using animal models. In this review, we describe how the zebrafish (Danio rerio) has been used as a powerful model to study host-virus interactions and inflammation by combining robust forward and reverse genetic tools with in vivo imaging of transparent embryos and larvae. The innate immune system has an essential role in the initial inflammatory response to viral infection. Focused studies of the innate immune response to viral infection are possible using the zebrafish model as there is a 4-6 week timeframe during development where they have a functional innate immune system dominated by neutrophils and macrophages. During this timeframe, zebrafish lack a functional adaptive immune system, so it is possible to study the innate immune response in isolation. Sequencing of the zebrafish genome has revealed significant genetic conservation with the human genome, and multiple studies have revealed both functional conservation of genes, including those critical to host cell infection and host cell inflammatory response. In addition to studying several fish viruses, zebrafish infection models have been developed for several human viruses, including influenza A, noroviruses, chikungunya, Zika, dengue, herpes simplex virus type 1, Sindbis, and hepatitis C virus. The development of these diverse viral infection models, coupled with the inherent strengths of the zebrafish model, particularly as it relates to our understanding of macrophage and neutrophil biology, offers opportunities for far more intensive studies aimed at understanding conserved host responses to viral infection. In this context, we review aspects relating to the evolution of innate immunity, including the evolution of viral pattern recognition receptors, interferons and interferon receptors, and non-coding RNAs.

Embryonic exposure to low concentrations of aflatoxin B1 triggers global transcriptomic changes, defective yolk lipid mobilization, abnormal gastrointestinal tract development and inflammation in zebrafish

Aflatoxin B1-contaminated feeds and foods induce various health problems in domesticated animals and humans, including tumor development and hepatotoxicity. Aflatoxin B1 also has embryotoxic effects in different livestock species and humans. However, it is difficult to distinguish between the indirect, maternally-mediated toxic effects and the direct embryotoxicity of aflatoxin B1 in mammals. In the present study, we investigated the aflatoxin B1-induced direct embryotoxic effects in a zebrafish embryo model system combining toxicological, transcriptomic, immunological, and biochemical approaches. Embryonic exposure to aflatoxin B1 induced significant changes at the transcriptome level resulting in elevated expression of inflammatory gene network and repression of lipid metabolism and gastrointestinal tract development-related gene sets. According to the gene expression changes, massive neutrophil granulocyte influx, elevated nitric oxide production, and yolk lipid accumulation were observed in the abdominal region of aflatoxin B1-exposed larvae. In parallel, aflatoxin B1-induced defective gastrointestinal tract development and reduced L-arginine level were found in our model system. Our results revealed the complex direct embryotoxic effects of aflatoxin B1, including inhibited lipid utilization, defective intestinal development, and inflammation.

Modeling Inflammation in Zebrafish for the Development of Anti-inflammatory Drugs.

Dysregulation of the inflammatory response in humans can lead to various inflammatory diseases, like asthma and rheumatoid arthritis. The innate branch of the immune system, including macrophage and neutrophil functions, plays a critical role in all inflammatory diseases. This part of the immune system is well-conserved between humans and the zebrafish, which has emerged as a powerful animal model for inflammation, because it offers the possibility to image and study inflammatory responses in vivo at the early life stages. This review focuses on different inflammation models established in zebrafish, and how they are being used for the development of novel anti-inflammatory drugs. The most commonly used model is the tail fin amputation model, in which part of the tail fin of a zebrafish larva is clipped. This model has been used to study fundamental aspects of the inflammatory response, like the role of specific signaling pathways, the migration of leukocytes, and the interaction between different immune cells, and has also been used to screen libraries of natural compounds, approved drugs, and well-characterized pathway inhibitors. In other models the inflammation is induced by chemical treatment, such as lipopolysaccharide (LPS), leukotriene B4 (LTB4), and copper, and some chemical-induced models, such as treatment with trinitrobenzene sulfonic acid (TNBS), specifically model inflammation in the gastro-intestinal tract. Two mutant zebrafish lines, carrying a mutation in the hepatocyte growth factor activator inhibitor 1a gene (hai1a) and the cdp-diacylglycerolinositol 3-phosphatidyltransferase (cdipt) gene, show an inflammatory phenotype, and they provide interesting model systems for studying inflammation. These zebrafish inflammation models are often used to study the anti-inflammatory effects of glucocorticoids, to increase our understanding of the mechanism of action of this class of drugs and to develop novel glucocorticoid drugs. In this review, an overview is provided of the available inflammation models in zebrafish, and how they are used to unravel molecular mechanisms underlying the inflammatory response and to screen for novel anti-inflammatory drugs.

Naoxintong restores ischemia injury and inhibits thrombosis via COX2-VEGF/ NFκB signaling

Ethnopharmacological relevanceNaoxintong (NXT) is a traditional Chinese medicine preparation that is often used in combination with aspirin in the treatment of cardiovascular diseases (CVD). One of the main symptoms of CVD is hypoxic-ischemia (HI). The purpose of this study is to find out the molecular nodes targeted by NXT and its related molecular pathways in vascular repair. Materials and methodsFirst, human vein umbilical endothelial cells (EA.hy926) were utilized to set up the Oxygen-Glucose Deprivation-Reoxygenation (OGD/R) model and treated with NXT. Cell proliferation, damage and apoptosis were detected by MTT, LDH, and flow cytometry assays. Second, transcriptional responses of OGD/R cells to NXT treatment were investigated. qRT-PCR, western blotting and inhibitor assays were performed. Third, the anti-thrombotic effect of NXT was evaluated by the zebrafish thrombosis model. Morphological observation, histological staining and qRT-PCR assays were implemented on zebrafish model to further observe in vivo the therapeutic effects of NXT on ischemia and thrombosis. ResultsIn OGD/R EA.hy926 cells, NXT treatment could reduce ischemic vascular injury, increase cell viability and decrease the proportion of apoptosis. Through RNA-seq analysis, 183 differentially expressed genes (DEGs) were screened with 110 up-regulated genes and 73 down-regulated genes between OGD/R and OGD/R + NXT treated EA.hy926 cells. VEGF and NFκB pathways were enriched. Among these genes, COX2 was identified as one of important targets via which NXT could restore vascular injury. COX2 inhibitor (NS-398), and aspirin, a drug that prevents the development of CVD by targeting COX2, exhibited similar effects to NXT in the treatment of OGD/R EA.hy926 cells. In zebrafish thrombosis model, NXT could attenuate tail venous thrombus and recover the quantity of heart red blood cells. Furthermore, NXT could prevent the formulation of thrombosis and eliminate inflammation in zebrafish by COX2-VEGF/NFκB signaling. ConclusionOur studies implicated that NXT could restore HI injury and inhibit thrombosis through COX2-VEGF/NFκB signaling, which is consistent with the molecular target of aspirin. This finding might explain the principle of NXT combined with aspirin in the treatment of cardiovascular diseases.

Review of inflammation in fish and value of the zebrafish model

Inflammation is a crucial step in the development of chronic diseases in humans. Understanding the inflammation environment and its intrinsic mechanisms when it is produced by harmful stimuli may be a key element in the development of human disease diagnosis. In recent decades, zebrafish (Danio rerio) have been widely used in research, due to their exceptional characteristics, as a model of various human diseases. Interestingly, the mediators released during the inflammatory response of both the immune system and nervous system, after its integration in the hypothalamus, could also facilitate the detection of injury through the register of behavioural changes in the fish. Although there are many studies that give well-defined information separately on such elements as the recruitment of cells, the release of pro- and anti-inflammatory mediators or the type of neurotransmitters released against different triggers, to the best of our knowledge there are no reviews that put all this knowledge together. In the present review, the main available information on inflammation in zebrafish is presented in order to facilitate knowledge about this important process of innate immunity, as well as the stress responses and behavioural changes derived from it.

Polyphenols in the Fermentation Liquid of Dendrobium candidum Relieve Intestinal Inflammation in Zebrafish Through the Intestinal Microbiome-Mediated Immune Response.

Previous studies of Dendrobium candidum (D. candidum), which is mainly distributed in tropical areas, have mainly focused on its functional polysaccharide; the effects of D. candidum polyphenols, the chemical composition of which may be improved by fermentation, have received limited attention, especially in in vivo models, which inevitably involve interactions with intestinal microorganisms. To address this challenge, metagenomic and metabolomic techniques, were applied, and immune factors and mucosal barrier-related proteins were determined to reveal the effects of fermented D. candidum polyphenols (FDC) on intestinal inflammation induced by oxazolone in zebrafish. The results showed that fermentation significantly changed the chemical composition of D. candidum and that FDC significantly improved the intestinal immune index. After the 21st day of FDC intervention, the abundance of Lactobacillus, Faecalibacterium, and Rummeliibacillus increased, but the abundance of the genera Shewanella, Geodermatophilus, Peptostreptococcaceae, and Mycobacterium decreased. At the same time, FDC significantly increased intestinal short-chain fatty acids (SCFAs). In addition, network analysis based on multi-omics indicated that FDC intake leads to changes in intestinal microbiota and intestinal metabolites, resulting in enhanced host immune function. These results indicate that FDC can improve intestinal health by regulating the intestinal microbiota and its metabolites to treat intestinal inflammation and regulate the host immune system. The present research improved our understanding of the utilization of D. candidum polyphenols and provided new evidence for the impacts of fermented D. candidum on host health.

Exploration of anti-inflammatory mechanism of forsythiaside A and forsythiaside B in CuSO4-induced inflammation in zebrafish by metabolomic and proteomic analyses

BackgroundInflammation is a general pathological phenomenon during severe disturbances to the homeostasis. Forsythiaside A (FA) and forsythiaside B (FB), isolated from the dried fruit of Forsythia suspensa (Thunb.) Vahl, are phenylethanoid compounds that show a significant anti-inflammatory effect. However, the properties and therapeutic mechanisms of this effect have not yet been systematically elucidated.MethodsIn this study, the anti-inflammatory effects of FA and FB were investigated in CuSO4-induced inflammation in zebrafish larvae. Intracellular generation of reactive oxygen species (ROS) and nitric oxide (NO) was investigated using fluorescence probes. Metabolomic and proteomic analyses using liquid chromatography-mass spectrometry were carried out to identify the expressions of metabolites and proteins associated with the anti-inflammatory mechanism of FA and FB. Quantitative polymerase chain reaction (PCR) was performed to detect the progressive changes in gene expression.ResultsFA and FB inhibited neutrophils migration to the damaged neuromasts and remarkably reduced CuSO4-induced ROS and NO generation in zebrafish larvae. Metabolomic analysis pointed to the involvement of nicotinate and nicotinamide metabolism, energy metabolism, pyrimidine metabolism, and purine metabolism. Proteomic analysis identified 146 differentially expressed proteins between the control and model groups. These included collagen [collagen type II alpha 1b precursor (col2a1b), collagen alpha-2(IX) chain precursor (col9a2), collagen type IX alpha I precursor (col9a1b)], nucleoside diphosphate kinase 3 isoform X1 (Nme3), WD repeat-containing protein 3 (Wdr3), and 28S ribosomal protein S7 mitochondrial precursor (Mrps7). FA and FB were shown to reverse the abnormal expressions of potential metabolite and protein biomarkers and alleviate CuSO4-induced damage to the neuromasts in the zebrafish lateral line.ConclusionsOur results indicate that FA and FB possess remarkable anti-inflammatory properties, protecting against CuSO4-induced neuromasts damage in zebrafish larvae. The results also suggest a multi-component and multi-regulatory therapeutic mechanism for FA and FB.

Deconvoluting Wavelengths Leading to Fluorescent Light Induced Inflammation and Cellular Stress in Zebrafish (Danio rerio)

Fluorescent light (FL) has been shown to induce a cellular immune and inflammatory response that is conserved over 450 MY of evolutionary divergence and among vertebrates having drastically different lifestyles such as Mus musculus, Danio rerio, Oryzias latipes and Xiphophorus maculatus. This surprising finding of an inflammation and immune response to FL not only holds for direct light receiving organs (skin) but is also observed within internal organs (brain and liver). Light responsive genetic circuitry initiated by the IL1B regulator induces a highly conserved acute phase response in each organ assessed for all of biological models surveyed to date; however, the specific light wavelengths triggering this response have yet to be determined so investigation of mechanisms and/or light specific molecule(s) leading to this response are difficult to assess. To understand how specific light wavelengths are received in both external and internal organs, zebrafish were exposed to specific 50 nm light wavebands spanning the visible spectrum from 300–600 nm and the genetic responses to each waveband exposure were assessed. Surprisingly, the induced cellular stress response previously observed following FL exposure is not triggered by the lower “damaging” wavelengths of light (UVB and UVA from 300–400 nm) but instead is maximally induced by higher wavelengths ranging from 450–500 nm in skin to 500–600 nm in both brain and liver).

Adhesion and anti-inflammatory potential of Lactobacillus rhamnosus GG in a sea buckthorn based beverage matrix.

The consumption of probiotic based foods due to their health promoting effects has increased over the years. The consumption of probiotic based foods, due to their health promoting effects, has increased over the years. Due to this rising demands, the application platforms of the food industry have directed their efforts in the development of novel functional probiotic beverages. The presence of dietary phenolics and other beneficial components has made fruit-based matrices more popular for probiotic delivery. However, very few studies to date have evaluated the impact of carrier matrices on the in vivo functionality of probiotic strains with specific biomarkers and targeted towards specific disease conditions. In this study, we investigated the effect of a sea buckthorn (Hippophae rhamnoides L.) based, malt supplemented, beverage matrix (SBT + M) on the physiological characteristics of the probiotic strain L. rhamnosus GG (ATCC 53103) (LR). No significant difference in the auto-aggregation and co-aggregation rates of LR fortified in SBT + M was observed compared to LR alone. Storage conditions (4 °C for 14 days) did not affect the survival and the adhesion potential of LR to the HCT116 cell line. More importantly, this study also determined the protective effect of SBT + M on the in vivo functionality of LR in alleviating LPS induced inflammation in zebrafish (Danio rerio). The results showed that administration with SBT + M + LR significantly alleviated the LPS induced colonic damage, evidenced by the decrease in the overall histological and goblet cell scores compared to the LPS-treated group. The protective effect of SBT + M + LR was higher compared to the effects of SBT + M or LR alone. The colonic expression of pro-inflammatory cytokines (TNF-α and IL-1β) showed a marked decline by 84.7% and 86.5% respectively. The highest expression of the anti-inflammatory cytokine IL-10 was recorded in the SBT + M + LR treated group (p < 0.001). The overall results reveal that the administration of SBT + M + LR showed the best effects in alleviating the LPS induced intestinal damage compared to the other test groups (SBT + M and LR). These protective effects could be attributed to the phenolic compounds present in the SBT matrix. Our study indicates the contributory role of the carrier matrix and merits further investigation for its use as a potential therapeutic agent for gastrointestinal inflammation.

Neutrophil phagocyte oxidase activity controls invasive fungal growth and inflammation in zebrafish.

Neutrophils are primary phagocytes of the innate immune system that generate reactive oxygen species (ROS) and mediate host defense. Deficient phagocyte NADPH oxidase (PHOX) function leads to chronic granulomatous disease (CGD) that is characterized by invasive infections, including those by the generally non-pathogenic fungus Aspergillus nidulans The role of neutrophil ROS in this specific host-pathogen interaction remains unclear. Here, we exploit the optical transparency of zebrafish to image the effects of neutrophil ROS on invasive fungal growth and neutrophil behavior in response to Aspergillus nidulans In a wild-type host, A. nidulans germinates rapidly and elicits a robust inflammatory response with efficient fungal clearance. PHOX-deficient larvae have increased susceptibility to invasive A. nidulans infection despite robust neutrophil infiltration. Expression of subunit p22phox (officially known as CYBA), specifically in neutrophils, does not affect fungal germination but instead limits the area of fungal growth and excessive neutrophil inflammation and is sufficient to restore host survival in p22phox-deficient larvae. These findings suggest that neutrophil ROS limits invasive fungal growth and has immunomodulatory activities that contribute to the specific susceptibility of PHOX-deficient hosts to invasive A. nidulans infection.