Structure of fish Toll-like receptors (TLR) and NOD-like receptors (NLR)

Plasmodium berghei TatD-like DNase hijacks host innate immunity by inhibiting the TLR9-NF-κB pathway

Neutrophils and macrophages confine pathogens by entrapping them in extracellular traps (ETs) through activating TLR9 function. However, plasmodial parasites secreted TatD-like DNases (TatD) to counteract ETs-mediated immune clearance. We found that TLR9 mutant mice increased susceptibility to rodent malaria, suggesting TLR9 is a key protein for host defense. We found that the proportion of neutrophils and macrophages in response to plasmodial parasite infection in the TLR9 mutant mice was significantly reduced compared to that of the WT mice. Importantly, PbTatD can directly bind to the surface TLR9 (sTLR9) on macrophages, which blocking the phosphorylation of mitogen-activated protein kinase and nuclear factor-κB, negatively regulated the signaling of ETs formation by both macrophages and neutrophils. Such, P. berghei TatD is a parasite virulence factor that can inhibit the proliferation of macrophages and neutrophils through directly binding to TLR9 receptors on the cell surface, thereby blocking the activation of the downstream MyD88-NF-kB pathways.

Analyses of the Mx family members in lumpfish: Molecular characterization, phylogeny, and gene expression analyses

Members of the myxovirus resistance (Mx) protein family play an essential role in antiviral immunity. They are Dynamin-like GTPases, induced by interferons. In the current study, we have characterized two predicted MX genes (MX1 and MX2) from lumpfish (Cyclopterus lumpus L.), having 12 and 13 exons, respectively. Mx2 has two isoforms (Mx2-X1 and Mx2-X2) which differ in exon 1. The lumpfish Mx proteins contain an N-terminal Dynamin-like GTPase domain, the middle domain (MD) and GTPase effector domain (GED) characteristic for Mx proteins. Phylogenetic analyses grouped all the lumpfish Mx sequences in group 1, and synteny analyses showed that both genes were localized at chromosome 5 in proximity to the genes Tohc7, Atxn7 and Psmd6. In vitro stimulation experiment showed that both MX1 and MX2-X2 were highly upregulated upon exposure to poly(I:C), but not bacteria, 24 h post exposure, indicating their role in antiviral immunity.

Transcriptomic analysis reveals bovine herpesvirus 1 infection regulates innate immune response resulted in restricted viral replication in neuronal cells

BACKGROUND

Bovine herpesvirus 1 (BoHV-1) is a major pathogen that affects the global bovine population, primarily inducing respiratory and reproductive disorders. Its ability to establish latent infections in neuronal cells and to reactivate under certain conditions poses a continual threat to uninfected hosts. In this study, we aimed to analyze the replication characteristics of BoHV-1 in neuronal cells, as well as the effects of viral replication on host cell immunity and physiology.

METHODS

Using the Neuro-2a neuronal-origin cell line as a model, we explored the dynamics of BoHV-1 replication and analyzed differential gene expression profiles post-BoHV-1 infection using high-throughput RNA sequencing.

RESULTS

BoHV-1 demonstrated restricted replication in Neuro-2a cells. BoHV-1 induced apoptotic pathways and enhanced the transcription of interferon-stimulated genes and interferon regulatory factors while suppressing the complement cascade in Neuro-2a cells.

CONCLUSIONS

Different from BoHV-1 infection in other non-highly differentiated somatic cells result in viral dominance, BoHV-1 regulated the innate immune response in neuronal cells formed a "virus-nerve cell" relative equilibrium state, which may account for the restricted replication of BoHV-1 in neuronal cells, leading to a latent infection. These findings provide a foundation for further research into the mechanism underlying BoHV-1-induced latent infection in nerve cells.

LL37-DNA Complex Drives Vitiligo Progression Through TLR9-MyD88 Signaling Pathways

Vitiligo is an autoimmune disorder characterized by chronic depigmentation and milk-white patches on the skin. Skin infiltration by autoreactive CD8+ T cells causes melanocyte destruction in vitiligo. Multiple risk factors, particularly immune-related inflammatory factors, are involved in the disappearance of melanocytes. LL37 is a classic damage-associated molecular pattern molecule that is involved in the development of various autoimmune diseases. An enhanced expression of LL37 in vitiligo is known; however, the exact role of LL37 in melanocyte loss has not yet been elucidated. In the present study, we detected increased LL37 expression in vitiligo serum and lesions. Furthermore, we confirmed that cultured keratinocytes released LL37 after treatment with H2O2. Moreover, the LL37-DNA complex enhanced the secretion of CXCL9, CXCL10, and CXCL16 from keratinocytes via the TLR9-MyD88 signaling pathway and facilitated the migration of CD8+ T cells. Altogether, our study demonstrates that LL37 released from keratinocytes binds to DNA and contributes to melanocyte destruction under oxidative stress-induced autoimmunity in vitiligo.

A Novel Manganese Ion Delivery Carrier Promotes Immune Cell Proliferation and Enhances Innate Immune Responses

Manganese is a transition metal that is an essential trace element for human health. Manganese ions (Mn2+), which serve as one of the most common transition metal ions, play vital roles in enhancing innate immune responses. However, immune agonists based on Mn2+ are poorly utilized in clinical trials due to poor chemodynamics and adverse events. In this work, we designed a novel delivery carrier for loading manganese ions by constructing hFn-MT3(Mn2+) protein nanoparticles (termed as NPs(Mn2+)), which contained human ferritin heavy chain (hFn) and metallothionein-3 (MT3), induced by isopropyl β-d-thiogalactoside (IPTG) and manganese ions in the prokaryotic expression system. The NPs(Mn2+) protein nanoparticles could not only stimulate immune cell proliferation but also activate innate immune responses via the cGAS-STING-IRF3 signaling pathway. Collectively, our results unveil a candidate strategy for delivering metal ions beyond Mn2+ and may broaden metal ion clinical use in the field of immunotherapies.

TLR4 induced TRPM2 mediated neuropathic pain

Ion channels play an important role in mediating pain through signal transduction, regulation, and control of responses, particularly in neuropathic pain. Transient receptor potential channel superfamily plays an important role in cation permeability and cellular signaling. Transient receptor potential channel Melastatin 2 (TRPM2) subfamily regulates Ca2+ concentration in response to various chemicals and signals from the surrounding environment. TRPM2 has a role in several physiological functions such as cellular osmosis, temperature sensing, cellular proliferation, as well as the manifestation of many disease processes such as pain process, cancer, apoptosis, endothelial dysfunction, angiogenesis, renal and lung fibrosis, and cerebral ischemic stroke. Toll-like Receptor 4 (TLR4) is a critical initiator of the immune response to inflammatory stimuli, particularly those triggered by Lipopolysaccharide (LPS). It activates downstream pathways leading to the production of oxidative molecules and inflammatory cytokines, which are modulated by basal and store-operated calcium ion signaling. The cytokine production and release cause an imbalance of antioxidant enzymes and redox potential in the Endoplasmic Reticulum and mitochondria due to oxidative stress, which results from TLR-4 activation and consequently induces the production of inflammatory cytokines in neuronal cells, exacerbating the pain process. Very few studies have reported the role of TRPM2 and its association with Toll-like receptors in the context of neuropathic pain. However, the molecular mechanism underlying the interaction between TRPM2 and TLR-4 and the quantum of impact in acute and chronic neuropathic pain remains unclear. Understanding the link between TLR-4 and TRPM2 will provide more insights into pain regulation mechanisms for the development of new therapeutic molecules to address neuropathic pain.

TAK-242 alleviates diabetic cardiomyopathy via inhibiting pyroptosis and TLR4/CaMKII/NLRP3 pathway

Diabetic cardiomyopathy (DCM) is identified as a progressive disease that may lead to irreparable heart failure. Toll-like receptor (TLR) signaling is believed to be implicated in the pathogenesis of DCM. This study intended to explore the potential impact of Toll-like receptor 4 (TLR4) on DCM in vitro and in vivo. Streptozotocin and HG medium were utilized to induce diabetes in animal and cell models, respectively. Selective TLR4 inhibitor TAK-242 and calcium/calmodulin-dependent protein kinase-II (CaMKII) inhibitor KN-93 were employed to explore the involvement of TLR4/CaMKII in DCM. TLR4 expression was increased in DCM hearts, while inhibition of TLR4 activation by TAK-242 improved cardiac function, attenuated heart hypertrophy, and fibrosis, as well as reduced oxidative stress and proinflammatory cytokine levels in rats, which were confirmed by Doppler echocardiography, hematoxylin and eosin staining, and Masson Trichome staining and specific enzyme-linked immunosorbent assay kits. Besides, the expression of hypertrophy-related molecules and oxidative stress damage were also inhibited by TAK-242. Furthermore, TAK-242 treatment reduced CaMKII phosphorylation accompanied by decreased expression of NOD-like pyrin domain-containing protein 3, gasdermin D (GSDMD), The N-terminal domain of Gasdermin D (GSDMD-N), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and Caspase-1 both in vivo and in vitro. Similar positive impacts on HG-induced pyroptosis were also observed with KN-93 treatment, and this was achieved without affecting TLR4 expression. Collectively, our work suggested that TAK-242 demonstrated substantial benefits against DCM both in vivo and in vitro, potentially attributed to the suppression of the TLR4-mediated CaMKII/NLRP3 pathway activity.

Protective effects of insulin on dry eye syndrome via TLR4/NF-κB pathway: based on network pharmacology and in vitro experiments validation

Dry eye syndrome (DES) is a multifactorial ocular surface disease and represents one of the most prevalent ophthalmic disorders. Insulin is an important metabolism-regulating hormone and a potential antioxidant with critical biological roles as anti-inflammatory and anti-apoptotic. However, its mechanism of action remains unknown. In this study, we used network pharmacology techniques and conducted cell experiments to investigate the protective effect of insulin on human corneal epithelial cells (HCECs). Eighty-seven common targets of insulin and DES were identified from the database. KEGG pathway enrichment analysis suggested that insulin may be crucial in regulating the toll-like receptor (TLR) signaling pathway by targeting key targets such as IL-6 and TNF. In cell experiments, insulin promoted HCECs proliferation, improved their ability to migrate, and inhibited apoptosis. Western blot and enzyme-linked immunosorbent assay (ELISA) also confirmed the upregulation of the expression of inflammatory factors such as IL-1β, IL-6, and proteins related to the TLR4/NF-κB signaling pathway. However, the expression of these proteins was inhibited by insulin administration. Our results preliminarily verified insulin may exert a protective role on HCECs under hyperosmotic condition, which offered a novel perspective for the clinical management of this condition.

HMGB1/TLR4 axis promotes pyroptosis after ICH by activating the NLRP3 inflammasome

BACKGROUND

We previously reported that the HMGB1/TLR4 axis promoted inflammation during the acute phase of intracerebral hemorrhage. Given that this phase is known to involve neuronal pyroptosis and neuroinflammation, here we explore whether HMGB1/TLR signaling activate inflammasome and pyroptosis after intracerebral hemorrhage.

METHODS

Autologous blood was injected into Sprague-Dawley rats to induce intracerebral hemorrhage. Neurological deficits were assessed using a modified neurological severity score. These expression and localization of NLRP1 and NLRP3 inflammasomes, as well as the levels of pyroptosis and pyroptosis-associated proteins were assessed using Western blot or immunocytochemistry. These experiments were repeated in animals that received treatment with short interfering RNAs against NLRP1 or NLRP3, with HMGB1 inhibitor ethyl pyruvate or TLR4 inhibitor TAK-242.

RESULTS

Intracerebral hemorrhage upregulated NLRP1 and NLRP3 in the ipsilateral striatum and increased the proportions of these cells that were pyroptosis-positive. Additionally, the levels of caspase protein family (e.g., pro-caspase-1 and caspase-1), apoptosis-associated speck-like protein (ASC), pro-interleukin-1β (IL-1β), and IL-1β were also elevated. These effects on pyroptosis and associated neurological deficit, were partially reversed by knockdown of NLRP1 or NLRP3, or by inhibition of HMGB1 or TLR4. Inhibition of HMGB1 or TLR4 resulted in the downregulation NLRP3 but not NLRP1.

CONCLUSIONS

The HMGB1/TLR4 signaling may activate the NLRP3 inflammasome during the acute phase of intracerebral hemorrhage, resulting in the inflammatory process known as pyroptosis. These insights suggest potential therapeutic targets for the mitigation tissue injury and associated neurological deficits following hemorrhagic stroke.

Mucosal organs exhibit distinct response signatures to hydrogen sulphide in Atlantic salmon (Salmo salar)

Hydrogen sulphide (H2S) is considered an immunotoxicant, and its presence in the water can influence the mucosal barrier functions of fish. However, there is a significant knowledge gap on how fish mucosa responds to low environmental H2S levels. The present study investigated the consequences of prolonged exposure to sub-lethal levels of H2S on the mucosal defences of Atlantic salmon (Salmo salar). Fish were continuously exposed to two levels of H2S (low: 0.05 µM; and high: 0.12 µM) for 12 days. Unexposed fish served as control. Molecular and histological profiling focused on the changes in the skin, gills and olfactory rosette. In addition, metabolomics and proteomics were performed on the skin and gill mucus. The gene expression profile indicated that the gills and olfactory rosette were more sensitive to H2S than the skin. The olfactory rosette showed a dose-dependent response, but not the gills. Genes related to stress responses were triggered at mucosal sites by H2S. Moreover, H2S elicited strong inflammatory responses, particularly in the gills. All mucosal organs demonstrated the key molecular repertoire for sulphide detoxification, but their temporal and spatial expression was not substantially affected by sub-lethal H2S levels. Mucosal barrier integrity was not considerably affected by H2S. Mucus metabolomes of the skin and gills were unaffected, but a matrix-dependent response was identified. Comparing the high-concentration group's skin and gills mucus metabolomes identified altered amino acid biosynthesis and metabolism pathways. The skin and gill mucus exhibited distinct proteomic profiles. Enrichment analysis revealed that proteins related to immunity and metabolism were affected in both mucus matrices. The present study expands our knowledge of the defence mechanisms against H2S at mucosal sites in Atlantic salmon. The findings offer insights into the health and welfare consequences of sub-lethal H2S, which can be incorporated into the risk assessment protocols in salmon land-based farms.

Stress and the gut-brain axis: an inflammatory perspective

The gut-brain axis (GBA) plays a dominant role in maintaining homeostasis as well as contributes to mental health maintenance. The pathways that underpin the axis expand from macroscopic interactions with the nervous system, to the molecular signals that include microbial metabolites, tight junction protein expression, or cytokines released during inflammation. The dysfunctional GBA has been repeatedly linked to the occurrence of anxiety- and depressive-like behaviors development. The importance of the inflammatory aspects of the altered GBA has recently been highlighted in the literature. Here we summarize current reports on GBA signaling which involves the immune response within the intestinal and blood-brain barrier (BBB). We also emphasize the effect of stress response on altering barriers' permeability, and the therapeutic potential of microbiota restoration by probiotic administration or microbiota transplantation, based on the latest animal studies. Most research performed on various stress models showed an association between anxiety- and depressive-like behaviors, dysbiosis of gut microbiota, and disruption of intestinal permeability with simultaneous changes in BBB integrity. It could be postulated that under stress conditions impaired communication across BBB may therefore represent a significant mechanism allowing the gut microbiota to affect brain functions.

Transforming Aquaculture through Vaccination: A Review on Recent Developments and Milestones

Aquaculture has rapidly emerged as one of the fastest growing industries, expanding both on global and on national fronts. With the ever-increasing demand for proteins with a high biological value, the aquaculture industry has established itself as one of the most efficient forms of animal production, proving to be a vital component of global food production by supplying nearly half of aquatic food products intended for human consumption. As in classic animal production, the prevention of diseases constitutes an enduring challenge associated with severe economic and environmental repercussions. Nevertheless, remarkable strides in the development of aquaculture vaccines have been recently witnessed, offering sustainable solutions to persistent health-related issues challenging resilient aquaculture production. These advancements are characterized by breakthroughs in increased species-specific precision, improved vaccine-delivery systems, and innovations in vaccine development, following the recent advent of nanotechnology, biotechnology, and artificial intelligence in the -omics era. The objective of this paper was to assess recent developments and milestones revolving around aquaculture vaccinology and provide an updated overview of strengths, weaknesses, opportunities, and threats of the sector, by incorporating and comparatively discussing various diffuse advances that span across a wide range of topics, including emerging vaccine technologies, innovative delivery methods, insights on novel adjuvants, and parasite vaccine development for the aquaculture sector.

IRF8 maintains mononuclear phagocyte and neutrophil function in acute kidney injury

Immune cells are key players in acute tissue injury and inflammation, including acute kidney injury (AKI). Their development, differentiation, activation status, and functions are mediated by a variety of transcription factors, such as interferon regulatory factor 8 (IRF8) and IRF4. We speculated that IRF8 has a pathophysiologic impact on renal immune cells in AKI and found that IRF8 is highly expressed in blood type 1 conventional dendritic cells (cDC1s), monocytes, monocyte-derived dendritic cells (moDCs) and kidney biopsies from patients with AKI. In a mouse model of ischemia‒reperfusion injury (IRI)-induced AKI, Irf8 -/- mice displayed increased tubular cell necrosis and worsened kidney dysfunction associated with the recruitment of a substantial amount of monocytes and neutrophils but defective renal infiltration of cDC1s and moDCs. Mechanistically, global Irf8 deficiency impaired moDC and cDC1 maturation and activation, as well as cDC1 proliferation, antigen uptake, and trafficking to lymphoid organs for T-cell priming in ischemic AKI. Moreover, compared with Irf8 +/+ mice, Irf8 -/- mice exhibited increased neutrophil recruitment and neutrophil extracellular trap (NET) formation following AKI. IRF8 primarily regulates cDC1 and indirectly neutrophil functions, and thereby protects mice from kidney injury and inflammation following IRI. Our results demonstrate that IRF8 plays a predominant immunoregulatory role in cDC1 function and therefore represents a potential therapeutic target in AKI.

Hepatic immune response of Coilia nasus infected with Anisakidae during ovarian development

Anisakidae parasitism is a prevalent disease in wild populations of Coilia nasus, and can result in a significant loss of germplasm resources. To elucidate the immune response mechanism of C. nasus livers to Anisakidae infection, we collected and analysed 18 parasitic and 18 non-parasitic livers at gonadal developmental stages II, III, and V using histopathology, molecular biology and transcriptome methods. The hepatic portal area of the parasitic group exhibited an increase in the fibrous stroma and thickened hepatic arteries with positive Ly-6G staining, indicating inflammation and immune responses in the liver. Hepatocyte cytokine levels and the expression of liver function-related genes indicated that fish livers responded similarly to Anisakidae parasitism across different gonadal developmental stages. Oxidative stress indices showed more intense changes in stage II samples, whereas gene expression levels of Nrf2 and C3 were significantly increased in parasitised livers during stage III and V. Liver transcriptome sequencing identified 2575 differentially expressed genes between the parasitic and non-parasitic groups at the three gonadal developmental stages. KEGG pathway analysis showed that natural killer cell-mediated cytotoxicity, the NOD-like receptor signaling pathway, neutrophil extracellular trap formation, and other immune pathways were significantly enriched. Expression patterns varied across developmental stages, suggesting that innate immunity was primarily responsible for the liver immune response to Anisakidae infection during C. nasus migration, possibly related to water temperature changes or shifts in the gonadal developmental stage. In summary, this study investigated the immune response of C. nasus to Anisakidae parasitism under natural conditions, focusing on reproductive aspects and environmental changes, thereby establishing a foundation for elucidating the molecular mechanisms underlying the immune response of Anisakidae in C. nasus.

USP14 negatively regulates IFN signaling by dampening K63-linked ubiquitination of TBK1 in black carp

USP14 regulates the immune related pathways by deubiquitinating the signaling molecules in mammals. In teleost, USP14 is also reported to inhibit the antiviral immune response through TBK1, but its regulatory mechanism remains obscure. To elucidate the role of USP14 in the RLR/IFN antiviral pathway in teleost, the homolog USP14 (bcUSP14) of black carp (Mylopharyngodon piceus) has been cloned and characterize in this paper. bcUSP14 contains 490 amino acids (aa), and the sequence is well conserved among in vertebrates. Over-expression of bcUSP14 in EPC cells attenuated SVCV-induced transcription activity of IFN promoters and enhanced SVCV replication. Knockdown of bcUSP14 in MPK cells led to the increased transcription of IFNs and decreased SVCV replication, suggesting the improved antiviral activity of the host cells. The interaction between bcUSP14 and bcTBK1 was identified by both co-immunoprecipitation and immunofluorescent staining. Co-expressed bcUSP14 obviously inhibited bcTBK1-induced IFN production and antiviral activity in EPC cells. K63-linked polyubiquitination of bcTBK1 was dampened by co-expressed bcUSP14, and bcTBK1-mediated phosphorylation and nuclear translocation of IRF3 were also inhibited by this deubiquitinase. Thus, all the data demonstrated that USP14 interacts with and inhibits TBK1 through deubiquitinating TBK1 in black carp.

Functional characterization of NOD1 from golden pompano Trachinotus ovatus

Fish rely on innate immune system for immunity, and nucleotide-binding oligomerization domain-like receptors (NLRs) are a vital group of receptor for recognition. In the present study, NOD1 gene was cloned and characterized from golden pompano Trachinotus ovatus, a commercially important aquaculture fish species. The ORF of T. ovatus NOD1 was 2820 bp long, encoding 939 amino acid residues with a highly conserved domains containing CARD-NACHT-LRRs. Phylogenetic analysis revealed that the T. ovatus NOD1 clustered with those of fish and separated from those of birds and mammals. T. ovatus NOD1 has wide tissue distribution with the highest expression in gills. Bacterial challenges (Streptococcus agalactiae and Vibrio alginolyticus) significantly up-regulated the expression of NOD1 with different response time. The results of T. ovatus NOD1 ligand recognition and signaling pathway analysis revealed that T. ovatus NOD1 could recognize iE-DAP at the concentration of ≧ 100 ng/mL and able to activate NF-κB signaling pathway. This study confirmed that NOD1 play a crucial role in the innate immunity of T. ovatus. The findings of this study improve our understanding on the immune function of NOD1 in teleost, especially T. ovatus.

The role of animal hosts in shaping gut microbiome variation

Millions of years of co-evolution between animals and their associated microbial communities have shaped and diversified the nature of their relationship. Studies continue to reveal new layers of complexity in host-microbe interactions, the fate of which depends on a variety of different factors, ranging from neutral processes and environmental factors to local dynamics. Research is increasingly integrating ecosystem-based approaches, metagenomics and mathematical modelling to disentangle the individual contribution of ecological factors to microbiome evolution. Within this framework, host factors are known to be among the dominant drivers of microbiome composition in different animal species. However, the extent to which they shape microbiome assembly and evolution remains unclear. In this review, we summarize our understanding of how host factors drive microbial communities and how these dynamics are conserved and vary across taxa. We conclude by outlining key avenues for research and highlight the need for implementation of and key modifications to existing theory to fully capture the dynamics of host-associated microbiomes. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.

Illicit Drugs in Surface Waters: How to Get Fish off the Addictive Hook

The United Nations World Drug Report published in 2022 alarmed that the global market of illicit drugs is steadily expanding in space and scale. Substances of abuse are usually perceived in the light of threats to human health and public security, while the environmental aspects of their use and subsequent emissions usually remain less explored. However, as with other human activities, drug production, trade, and consumption of drugs may leave their environmental mark. Therefore, this paper aims to review the occurrence of illicit drugs in surface waters and their bioaccumulation and toxicity in fish. Illicit drugs of different groups, i.e., psychostimulants (methamphetamines/amphetamines, cocaine, and its metabolite benzoylecgonine) and depressants (opioids: morphine, heroin, methadone, fentanyl), can reach the aquatic environment through wastewater discharge as they are often not entirely removed during wastewater treatment processes, resulting in their subsequent circulation in nanomolar concentrations, potentially affecting aquatic biota, including fish. Exposure to such xenobiotics can induce oxidative stress and dysfunction to mitochondrial and lysosomal function, distort locomotion activity by regulating the dopaminergic and glutamatergic systems, increase the predation risk, instigate neurological disorders, disbalance neurotransmission, and produce histopathological alterations in the brain and liver tissues, similar to those described in mammals. Hence, this drugs-related multidimensional harm to fish should be thoroughly investigated in line with environmental protection policies before it is too late. At the same time, selected fish species (e.g., Danio rerio, zebrafish) can be employed as models to study toxic and binge-like effects of psychoactive, illicit compounds.

Regulation of the AGEs-induced inflammatory response in human periodontal ligament cells via the AMPK/NF-κB/ NLRP3 signaling pathway

The heightened prevalence and accelerated progression of periodontitis in individuals with diabetes is primarily attributed to inflammatory responses in human periodontal ligament cells (HPDLCs). This study is aimed at delineating the regulatory mechanism of nucleotide-binding oligomerization domain-like receptors (NLRs) in mediating inflammation incited by muramyl dipeptide (MDP) in HPDLCs, under the influence of advanced glycation end products (AGEs), metabolic by-products associated with diabetes. We performed RNA-seq in HPDLCs induced by AGEs treatment and delineated activation markers for the receptor of AGEs (RAGE). It showed that advanced glycation end products modulate inflammatory responses in HPDLCs by activating NLRP1 and NLRP3 inflammasomes, which are further regulated through the NF-κB signaling pathway. Furthermore, AGEs synergize with NOD2, NLRP1, and NLRP3 inflammasomes to augment MDP-induced inflammation significantly.

Identification of the NOD-like receptor family of golden pompano and expression in response to bacterial and parasitic exposure reveal its key role in innate immunity

This study presents a genome-wide identification of NOD-like receptors (NLRs) in the golden pompano, key to its innate immunity. We identified 30 ToNLRs, analyzing their chromosomal positions, characteristics, evolutionary relationships, evidence of positive selection, and synteny with the yellowtail kingfish. Our findings categorize these NLRs into three main subgroups: NLRA, NLRC, and the distinct ToNLRX1. Post-exposure to Streptococcus agalactiae, most ToNLRs increased expression in the spleen, whereas NLRC3like13, NLRC3like16, and NLRC3like19 so in the kidneys. Upon Cryptocaryon irritans exposure, we categorized our groups based on the site of infection into the control group (BFS), the trophont-attached skin (TAS), and the nearby region skin (NRS). ToAPAF1 and ToNOD1 expressions rose in the NRS, in contrast to decreased expressions of ToNLRC5, ToNWD1 and ToCIITA. Other ToNLRs showed variable expressions in the TAS. Overall, this research lays the groundwork for further exploration of innate immunity in the golden pompano.

Exopolysaccharide secreted by Lactiplantibacillus plantarum Y12 showed inhibitory effect on the pathogenicity of Shigella flexneri in vitro and in vivo

Shigella flexneri is a prevalent foodborne and waterborne pathogen that threatens human health. Our previous research indicated that the Lactiplantibacillus plantarum Y12 exopolysaccharide (L-EPS) potentially inhibited the pathogenicity of S. flexneri. The in vitro results of this study demonstrated that L-EPS effectively mitigated the symptoms induced by S. flexneri in HT-29 cells, including inhibited gene expression levels of IL-1β, IL-6, IL-8, TNF-α, TLR 2/4, and NOD1/2; decreased apoptosis ratio; and alleviated damage degree of intestinal barrier function (Zona occludens 1, Occludin, and Claudin-1). The in vivo results demonstrated that S. flexneri treated with L-EPS elicited mild adverse physiological manifestations, an inflammatory response, and tissue damage. The infection of S. flexneri caused significant alterations in the abundance of phylum (Firmicutes, Bacteroidota, Actinobacteriota, and Proteobacteria), family (Lachnospiraceae, Muribaculaceae, Rikenellaceae, Prevotellaceaea, Ruminococcaceae, and Lactobaillaceae), and genus (Escherichia Shigella and Lachnospirillaceae NK4A136 group) within the cecal microbiota. These changes were accompanied by perturbations in taurine and hypotaurine metabolism, tricarboxylic acid (TCA) cycle activity, arginine biosynthesis, and histidine metabolic pathways. However, intervention with L-EPS attenuated the dysbiosis of cecal microbiota and metabolic disturbances. In summary, our research suggested a potential application of L-EPS as a functional food additive for mitigating S. flexneri infection.

UNC93B1 facilitates the localization and signaling of TLR5M in Epinephelus coioides

Toll-like receptor 5 (TLR5), serving as a sensor of bacterial flagellin, mediates the innate immune response to actively engage in the host's immune processes against pathogen invasion. However, the mechanism underlying TLR5-mediated immune response in fish remains unclear. Despite the presumed cell surface expression of TLR5 member form (TLR5M), its trafficking dynamics remain elusive. Here, we have identified Epinephelus coioides TLR5M as a crucial mediator of Vibrio flagellin-induced cytokine expression in grouper cells. EcTLR5M facilitated the activation of NF-κB signaling pathway in response to flagellin stimulation and exerted a modest influence on the mitogen-activated protein kinase (MAPK)-extracellular regulated kinase (ERK) signaling. The trafficking chaperone Unc-93 homolog B1 (EcUNC93B1) participated in EcTLR5M-mediated NF-κB signaling activation and downstream cytokine expression. In addition, EcUNC93B1 combined with EcTLR5M to mediate its exit from the endoplasmic reticulum, and also affected its post-translational maturation. Collectively, these findings first discovered that EcTLR5M mediated the flagellin-induced cytokine expression primarily by regulating the NF-κB signaling pathway, and EcUNC93B1 mediated EcTLR5M function through regulating its trafficking and post-translational maturation. This research expanded the understanding of fish innate immunity and provided a novel concept for the advancement of anti-vibrio immunity technology.

Fenpropathrin disrupted the gills of common carp (Cyprinus carpio L.) through oxidative stress, inflammatory responses, apoptosis, and transcriptional alterations

Fenpropathrin (FEN) is an extensively utilized synthetic pyrethroid insecticide frequently found in aquatic ecosystems. However, the adverse effects and potential mechanisms of FEN on aquatic species are poorly understood. In this work, common carp were treated with FEN at concentrations of 0.45 and 1.35 μg/L FEN for 14 days, after which the tissue structure, physiological alterations, and mRNA transcriptome of the gills were evaluated. Specifically, FEN exposure caused pathological damage to the gills of carp, downregulated the levels of claudin-1, occludin, and zonula occluden-1 (ZO-1), and inhibited Na+-K+-ATPase activity in the gills. In addition, FEN exposure promoted an increase in reactive oxygen species (ROS) levels and significantly upregulated the levels of malondialdehyde (MDA), 8-hydroxy-2 deoxyguanosine (8-OHdG), and protein carbonyl (PC) in the gills. Moreover, the inflammation-related indices (TNF-α, IL-1β, and IFN-γ) and the apoptosis-related parameter caspase-3 were generally increased, especially in the 1.35 μg/L FEN group, and these indices were significantly greater than those in the control group. These findings suggest that FEN exposure can cause oxidative stress, the inflammatory response, and apoptosis in carp gills. Importantly, the results of RNA-seq analysis showed that 0.45 and 1.35 μg/L FEN could significantly interfere with multiple immune and metabolic pathways, including the phagosome, NOD-like receptor (NLR) signalling pathway, Toll-like receptor (TLR) signalling pathway, necroptosis, and arachidonic acid metabolism pathways, indicating that the effects of FEN on the gills of fish are intricate. In summary, our findings confirm the toxic effects of FEN on common carp gills and provide additional comprehensive information for evaluating the toxicity and underlying molecular mechanisms of FEN in aquatic organisms.

Identification of 4 autophagy-related genes in heart failure by bioinformatics analysis and machine learning

Introduction

Autophagy refers to the process of breaking down and recycling damaged or unnecessary components within a cell to maintain cellular homeostasis. Heart failure (HF) is a severe medical condition that poses a serious threat to the patient's life. Autophagy is known to play a pivotal role in the pathogenesis of HF. However, our understanding of the specific mechanisms involved remains incomplete. Here, we identify autophagy-related genes (ARGs) associated with HF, which we believe will contribute to further comprehending the pathogenesis of HF.

Methods

By searching the GEO (Gene Expression Omnibus) database, we found the GSE57338 dataset, which was related to HF. ARGs were obtained from the HADb and HAMdb databases. Annotation of GO and enrichment analysis of KEGG pathway were carried out on the differentially expressed ARGs (AR-DEGs). We employed machine learning algorithms to conduct a thorough screening of significant genes and validated these genes by analyzing external dataset GSE76701 and conducting mouse models experimentation. At last, immune infiltration analysis was conducted, target drugs were screened and a TF regulatory network was constructed.

Results

Through processing the dataset with R language, we obtained a total of 442 DEGs. Additionally, we retrieved 803 ARGs from the database. The intersection of these two sets resulted in 15 AR-DEGs. Upon performing functional enrichment analysis, it was discovered that these genes exhibited significant enrichment in domains related to "regulation of cell growth", "icosatetraenoic acid binding", and "IL-17 signaling pathway". After screening and verification, we ultimately identified 4 key genes. Finally, an analysis of immune infiltration illustrated significant discrepancies in 16 distinct types of immune cells between the HF and control group and up to 194 potential drugs and 16 TFs were identified based on the key genes.

Discussion

In this study, TPCN1, MAP2K1, S100A9, and CD38 were considered as key autophagy-related genes in HF. With these relevant data, further exploration of the molecular mechanisms of autophagy in HF can be carried out.

Effect of aqueous extract of Millettia speciosa Champ on intestinal health maintenance and immune enhancement of Cyprinus carpio

Millettia speciosa Champ (MSP) is a natural Chinese herb that improves gastrointestinal health and enhances animal immunity. An 8-week feeding trial with different MSP levels (0, 150, 300, and 600 mg/kg) was conducted to evaluate the promotive effects of MSP in Cyprinus carpio. Results indicate that MSP improved intestinal immunity to some extent evidenced by the immuno-antioxidant parameters and the 16S rRNA in the Illumina MiSeq platform. With the analysis of transcriptome sequencing, 4685 differentially expressed genes (DEGs) were identified, including 2149 up-regulated and 2536 down-regulated. According to the GO and KEGG enrichments, DEGs were mainly involved in the immune system. Transcriptional expression of the NOD-like signaling pathway and key genes retrieved from the transcriptome database confirmed that innate immunity was improved in response to dietary MSP administration. Therefore, MSP could be used as a feed supplement that enhances immunity. This may provide insight into Chinese herb additive application in aquaculture production.

A comprehensive review on the dynamic role of toll-like receptors (TLRs) in frontier aquaculture research and as a promising avenue for fish disease management

Toll-like receptors (TLRs) represent a conserved group of germline-encoded pattern recognition receptors (PRRs) that recognize pathogen-associated molecular patterns (PAMPs) and play a crucial role in inducing the broadly acting innate immune response against pathogens. In recent years, the detection of 21 different TLR types in various fish species has sparked interest in exploring the potential of TLRs as targets for boosting immunity and disease resistance in fish. This comprehensive review offers the latest insights into the diverse facets of fish TLRs, highlighting their history, classification, architectural insights through 3D modelling, ligands recognition, signalling pathways, crosstalk, and expression patterns at various developmental stages. It provides an exhaustive account of the distinct TLRs induced during the invasion of specific pathogens in various fish species and delves into the disparities between fish TLRs and their mammalian counterparts, highlighting the specific contribution of TLRs to the immune response in fish. Although various facets of TLRs in some fish, shellfish, and molluscs have been described, the role of TLRs in several other aquatic organisms still remained as potential gaps. Overall, this article outlines frontier aquaculture research in advancing the knowledge of fish immune systems for the proper management of piscine maladies.

Fishing Innate Immune System Properties through the Transcriptomic Single-Cell Data of Teleostei

The innate immune system is the first line of defense in multicellular organisms. Danio rerio is widely considered a promising model for IIS-related research, with the most amount of scRNAseq data available among Teleostei. We summarized the scRNAseq and spatial transcriptomics experiments related to the IIS for zebrafish and other Teleostei from the GEO NCBI and the Single-Cell Expression Atlas. We found a considerable number of scRNAseq experiments at different stages of zebrafish development in organs such as the kidney, liver, stomach, heart, and brain. These datasets could be further used to conduct large-scale meta-analyses and to compare the IIS of zebrafish with the mammalian one. However, only a small number of scRNAseq datasets are available for other fish (turbot, salmon, cavefish, and dark sleeper). Since fish biology is very diverse, it would be a major mistake to use zebrafish alone in fish immunology studies. In particular, there is a special need for new scRNAseq experiments involving nonmodel Teleostei, e.g., long-lived species, cancer-resistant fish, and various fish ecotypes.

TRIM25 negatively regulates IKKε-mediated interferon signaling in black carp

IKKε plays an important role in the activation of IRF3/IRF7 and the production of interferon (IFN), however, its regulation remains obscure in human. E3 ligase TRIM25 has been reported to manipulate the K63-linked ubiquitination of RIG-I, leading to the activation of RIG-I/IFN signaling. To elucidate the role of TRIM25 in teleost, a TRIM25 homolog (bcTRIM25) was cloned and characterized from black carp (Mylopharyngodon piceus). bcTRIM25 contains 653 amino acids, possessing conservative RING, B-box and SPRY domain, which is highly expressed in muscle, spleen and skin. bcTRIM25 knock-down enhanced the antiviral ability of host cells. bcTRIM25 over-expression alone in EPC cells attenuated bcIFNa promoter transcription in the reporter assays and impeded PKR and MX1 expression in qRT-PCR. Interestingly, co-IP assays indicated that bcTRIM25 interacted with bcIKKε and the induced bcIFNa promoter transcription by bcIKKε was notably hindered by bcTRIM25. Furthermore, bcIKKε-induced expression of interferon stimulated genes (ISGs) and antiviral activity were dampened by bcTRIM25. Further exploration showed that bcTRIM25 visibly enhanced the ubiquitination of bcIKKε but significantly attenuated the phosphorylation of bcIKKε. Thus, our data demonstrate for the first time in vertebrate that TRIM25 negatively regulates IKKε through enhancing its ubiquitination, which sheds a light on the regulation of IKKε/IFN signaling.

Effects of β-1,3-glucan on growth, immune responses, and intestinal microflora of the river prawn (Macrobrachium nipponense) and its resistance against Vibrio parahaemolyticus

In this study, we investigated the impact of β-1,3-glucan on the immune responses and gut microbiota of the river prawn (Macrobrachium nipponense) in the presence of Vibrio parahaemolyticus stress. Shrimps were fed one of the following diets: control (G1), 0.2% curdlan (G2), 0.1% β-1,3-glucan (G3), 0.2% β-1,3-glucan (G4), or 1.0% β-1,3-glucan (G5) for 6 weeks and then challenged with V. parahaemolyticus for 96 h. Under Vibrio stress, shrimps in G4 exhibited the highest length gain rate, weight gain rate, and survival rate. They also showed increased intestinal muscle thickness and villus thickness compared to the control and 0.2% curdlan groups. The apoptosis rate was lower in G4 than in the control group, and the digestive enzyme activities (pepsin, trypsin, amylase, and lipase), immune enzyme activities (acid phosphatase, alkaline phosphatase, lysozyme, and phenoxidase), and energy metabolism (triglyceride, cholesterol, glycogen, and lactate dehydrogenase) were enhanced. Expression levels of growth-related genes (ecdysone receptor, calmodulin-dependent protein kinase I, chitin synthase, and retinoid X receptor) and immune-related genes (toll-like receptor 3, myeloid differentiation primary response 88, mitogen-activated protein kinase 7, and mitogen-activated protein kinase 14) were higher in G4 than in the control. Microbiota analysis indicated higher bacterial abundance in shrimps fed β-1,3-glucan, as evidenced by Sob, Chao1, and ACE indices. Moreover, 0.2% β-1,3-glucan increased the relative abundances of Bacteroidota and Firmicutes while reducing those of Corynebacteriales and Lactobacillales. In summary, β-1,3-glucan enhances immune enzyme activities, alters immune-related gene expression, and impacts gut microbial diversity in shrimp. These findings provide valuable insights into the mechanisms underlying β-1,3 glucan's immune-enhancing effects.

Genome-wide DNA methylation mediates the resistance to vibriosis in Cynoglossus semilaevis

Chinese tongue sole (Cynoglossus semilaevis) is an economically important marine fish in China. However, vibriosis has caused huge mortality and economic losses in its culturing industry. To reveal the effect of DNA methylation on the resistance to vibriosis in tongue sole, we conducted RNA sequencing and whole genome bisulfite sequencing (WGBS), and compared the gene expressions and DNA methylation patterns between the resistant and susceptible families. We identified a total of 741 significantly differentially expressed genes (DEGs) in kidney and 17460 differentially methylated genes (DMGs), which were both enriched in immune-related pathways, such as "cAMP signaling pathway" and "NOD-like receptor signaling pathway". Through the correlation analysis of DEGs and DMGs, we identified two important immune pathways, including "complement and coagulation cascades", and "cytokine-cytokine receptor interaction", which played important roles in regulating the inflammation level and immune homeostasis. For example, the expression of proinflammatory cytokine il17c was down-regulated under the regulation of DNA methylation; in addition, the expression of protease-activated receptor 3 (par3) was up-regulated, which could induce the up-expressionof il8. These results demonstrated that the regulation of DNA methylation on the genes involved in immune responses might contribute to the resistance to vibriosis in tongue sole, and provided a basis for the control of diseases in fish aquaculture.

Exposure of zebrafish (Danio rerio) to graphene oxide for 6 months suppressed NOD-like receptor-regulated anti-virus signaling pathways

Environmental exposure to graphene oxide (GO) is likely to happen due to the use and disposal of these materials. Although GO-induced ecological toxicity has been evaluated before by using aquatic models such as zebrafish, previous studies typically focused on the short-term toxicity, whereas this study aimed to investigate the long-term toxicity. To this end, we exposed zebrafish to GO for 6 months, and used RNA-sequencing to reveal the changes of signaling pathways. While GO exposure showed no significant effects on locomotor activities, it induced histological changes in livers. RNA-sequencing data showed that GO altered gene expression profiles, resulting in 82 up-regulated and 275 down-regulated genes, respectively. Through the analysis of gene ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, we found that GO suppressed the signaling pathways related with immune systems. We further verified that GO exposure suppressed the expression of genes involved in anti-virus responses possibly through the inhibition of genes involved in NOD-like receptor signaling pathway. Furthermore, NOD-like receptor-regulated lipid genes were also inhibited, which may consequently lead to decreased lipid staining in fish muscles. We concluded that 6 month-exposure to GO suppressed NOD-like receptor-regulated anti-virus signaling pathways in zebrafish.

Grass carp (Ctenopharyngodon idella) Mex3B positively regulates innate immunity by promoting the K63-linked ubiquitination of TLR3

As a member of Mex3 (muscle excess protein-3) family, Mex3B (Mex-3 RNA binding family member B) is crucial in cell proliferation and migration in mammals. In this study, an ortholog of mammalian Mex3B (denominated CiMex3B, MT276802.1) was cloned and identified in grass carp (Ctenopharyngodon idella). CiMex3B is 1578 bp in length and encodes a polypeptide of 525 amino acids. Consistent with its mammalian counterpart, CiMex3B also contains one C-terminal RING domain and two N-terminal conserved tandem KH domains. CiMex3B up-regulates the expressions of IFN1, ISG15, MX2, as well as the expressions of inflammatory cytokines such as IL6, IL8 and TNFα in response to poly(I:C). A screening test for identifying potential targets indicated that CiMex3B is associated with TLR3 and TRIF. CiMex3B co-localizes with TLR3 in the late endosome, mitochondria and endoplasmic reticulum after poly(I:C) stimulation, whereas they are rarely discovered in the lysosomes. CiMex3B serves as a positive regulator in the phosphorylation of IRF3 and induces IFN1 expression. In addition, two truncation mutants of CiMex3B (1-220 and 221-525) were constructed to better understand the molecular mechanism of CiMex3B-mediated ubiquitination of TLR3. In line with wild-type protein, CiMex3B mutant (1-220) was found mainly in the cytoplasm; however, CiMex3B mutant (221-525) resided in the cytoplasm and the nucleus as well, and it was further confirmed that CiMex3B mutant (221-525) still interacts with TLR3. We also observed that CiMex3B promotes the K63-linked ubiquitination of TLR3, while neither of the truncation mutants (1-220 or 221-525) retains this activity. To sum up, this study revealed that CiMex3B potentiates the K63-linked ubiquitination of TLR3, and then elicits the IRF3-mediated antiviral innate immune responses.

Genome-wide identification, phylogenetic relationships and expression patterns of the NOD-like receptor (NLR) gene family in flounder (Paralichthys olivaceus)

NOD-like receptors (NLRs) are one of the pattern recognition receptors which have been widely known for identifying pathogens and regulating innate immunity in mammals, but the functions of the NLR gene family in teleost fish remain poorly understood. In this study, we conducted a comprehensive identification and analysis of the flounder (Paralichthys olivaceus) NLR gene family, including bioinformatics information, evolutionary relationships, gene structures, conserved motifs, domain composition, expression patterns and protein-protein interaction (PPI). We identified 22 NLRs in flounder (flNLRs) which were clustered into three subfamilies according to their domain organizations and phylogenetic features, i.e., NLR-A (6 members) resembling mammalian NODs, NLR-B (1 member) resembling mammalian NLRPs, and NLR-C (15 members) unique to teleost fish. All flNLRs shared a conserved NACHT domain including an N-terminal nucleotide-binding domain, a middle helical domain 1, and a winged helix domain. Gene structure analysis displayed that flNLRs were significantly different, with exon numbers from 1 to 52. Conserved domain analysis showed that the N-terminus of flNLRs possessed different characteristics of the domains including CARD domain, PYRIN domain, RING domain, and fish-specific FISNA domain, and the C-terminus of seven NLR-C members contained an extra B30.2 domain, named NLRC-B30.2 group. Notably, flNLRs were expressed in all nine tested tissues, showing higher expressions in the systemic and mucosal immune tissues (e.g., kidney, spleen, hindgut, gills, skin, liver) in healthy flounder, and significant responses to intraperitoneal injection and immersion immunization of inactivated Vibrio anguillarum in mucosal tissues, especially the NLR-C members. In addition, PPI analysis demonstrated that some flNLRs of NLR-A and NLR-C shared the same interacting proteins such as RIPK2, TRAF6, MAVS, CASP, ASC, and ATG5, suggesting they might play crucial roles in host defense, antiviral innate immunity, inflammation, apoptosis and autophagy. This study for the first time characterized the NLR gene family of flounder at the genome-wide level, and the results provided a better understanding of the evolution of the NLR gene family and their immune functions in innate immunity in fish.

Revealing the Salmo salar NLRP3 Inflammasome: Insights from Structural Modeling and Transcriptome Analysis

The NLRP3, one of the most heavily studied inflammasome-related proteins in mammals, remains inadequately characterized in Atlantic salmon (Salmo salar), despite the significant commercial importance of this salmonid. The NLRP3 inflammasome is composed of the NLRP3 protein, which is associated with procaspase-1 via an adapter molecule known as ASC. This work aims to characterize the Salmo salar NLRP3 inflammasome through in silico structural modeling, functional transcript expression determination in the SHK-1 cell line in vitro, and a transcriptome analysis on Atlantic salmon. The molecular docking results suggested a similar arrangement of the ternary complex between NLRP3, ASC, and caspase-1 in both the Atlantic salmon and the mammalian NLRP3 inflammasomes. Moreover, the expression results confirmed the functionality of the SsNLRP3 inflammasome in the SHK-1 cells, as evidenced by the lipopolysaccharide-induced increase in the transcription of genes involved in inflammasome activation, including ASC and NLRP3. Additionally, the transcriptome results revealed that most of the inflammasome-related genes, including ASC, NLRP3, and caspase-1, were down-regulated in the Atlantic salmon following its adaptation to seawater (also known as parr-smolt transformation). This is correlated with a temporary detrimental effected on the immune system. Collectively, these findings offer novel insights into the evolutionarily conserved role of NLRP3.

Histomorphological Changes in Fish Gut in Response to Prebiotics and Probiotics Treatment to Improve Their Health Status: A Review

The gastrointestinal tract (GIT) promotes the digestion and absorption of feeds, in addition to the excretion of waste products of digestion. In fish, the GIT is divided into four regions, the headgut, foregut, midgut, and hindgut, to which glands and lymphoid tissues are associated to release digestive enzymes and molecules involved in the immune response and control of host-pathogens. The GIT is inhabited by different species of resident microorganisms, the microbiota, which have co-evolved with the host in a symbiotic relationship and are responsible for metabolic benefits and counteracting pathogen infection. There is a strict connection between a fish's gut microbiota and its health status. This review focuses on the modulation of fish microbiota by feed additives based on prebiotics and probiotics as a feasible strategy to improve fish health status and gut efficiency, mitigate emerging diseases, and maximize rearing and growth performance. Furthermore, the use of histological assays as a valid tool for fish welfare assessment is also discussed, and insights on nutrient absorptive capacity and responsiveness to pathogens in fish by gut morphological endpoints are provided. Overall, the literature reviewed emphasizes the complex interactions between microorganisms and host fish, shedding light on the beneficial use of prebiotics and probiotics in the aquaculture sector, with the potential to provide directions for future research.

Yeast polysaccharide mitigated oxidative injury in broilers induced by mixed mycotoxins via regulating intestinal mucosal oxidative stress and hepatic metabolic enzymes

This study was aimed to investigate the effects of yeast polysaccharides (YPS) on growth performance, intestinal health, and aflatoxin metabolism in livers of broilers fed diets naturally contaminated with mixed mycotoxins (MYCO). A total of 480 one-day-old Arbor Acre male broilers were randomly allocated into a 2 × 3 factorial arrangement of treatments (8 replicates with 10 birds per replicate) for 6 wk to assess the effects of 3 levels of YPS (0, 1, or 2 g/kg) on the broilers fed diets contaminated with or without MYCO (95 μg/kg aflatoxin B1, 1.5 mg/kg deoxynivalenol, and 490 μg/kg zearalenone). Results showed that mycotoxins contaminated diets led to significant increments in serum malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, mRNA expressions of TLR4 and 4EBP1 associated with oxidative stress, mRNA expressions of CYP1A1, CYP1A2, CYP2A6, and CYP3A4 associated with hepatic phase Ⅰ metabolizing enzymes, mRNA expressions of p53 associated with hepatic mitochondrial apoptosis, and AFB1 residues in the liver (P < 0.05); meanwhile dietary MYCO decreased the jejunal villus height (VH), villus height/crypt depth (VH/CD), the activity of serum total antioxidant capacity (T-AOC), mRNA expressions of jejunal HIF-1α, HMOX, and XDH associated with oxidative stress, mRNA expressions of jejunal CLDN1, ZO1, and ZO2, and mRNA expression of GST associated with hepatic phase Ⅱ metabolizing enzymes of broilers (P < 0.05). Notably, the adverse effects induced by MYCO on broilers were mitigated by supplementation with YPS. Dietary YPS supplementation reduced the concentrations of serum MDA and 8-OHdG, jejunal CD, mRNA expression of jejunal TLR2, and 4EBP1, hepatic CYP1A2, and p53, and the AFB1 residues in the liver (P < 0.05), and elevated the serum T-AOC and SOD, jejunal VH, and VH/CD, and mRNA expression of jejunal XDH, hepatic GST of broilers (P < 0.05). There were significant interactions between MYCO and YPS levels on the growth performance (BW, ADFI, ADG, and F/G) at d 1 to 21, d 22 to 42, and d 1 to 42, serum GSH-Px activity, and mRNA expression of jejunal CLDN2 and hepatic ras of broilers (P < 0.05). In contrast with MYCO group, the addition of YPS increased BW, ADFI, and ADG, the serum GSH-Px activity (14.31%-46.92%), mRNA levels of jejunal CLDN2 (94.39%-103.02%), decreased F/G, and mRNA levels of hepatic ras (57.83%-63.62%) of broilers (P < 0.05). In conclusion, dietary supplements with YPS protected broilers from mixed mycotoxins toxicities meanwhile keeping normal performance of broilers, presumably via reducing intestinal oxidative stress, protecting intestinal structural integrity, and improving hepatic metabolic enzymes to minimize the AFB1 residue in the liver and enhance the performance of broilers.

The Immunological Capacity of Thrombocytes

Thrombocytes are numerous in the blood of aves (birds) and ichthyoids (fish). The origin of this cell type is a common hematopoietic stem cell giving rise to a cell that is active in blood coagulation, inflammatory functions, and the immune response in general. It has been well documented that thrombocytes can phagocytize small particles and bacteria. While phagocytosis with an associated oxidative burst has been reported for chicken thrombocytes, some questions remain as to the degradation capacity of phagosomes in ichthyoids. As innate cells, thrombocytes can be stimulated by bacterial, viral, and fungal pathogens to express altered gene expression. Furthermore, there have been observations that led researchers to state that platelets/thrombocytes are capable of serving as "professional antigen presenting cells" expressing CD40, CD80/86, MHC I, and MHC II. This indeed may be the case or, more likely at this time, provide supporting evidence that these cells aid and assist in the role of professional antigen-presenting cells to initiate adaptive immune responses.

YAP/TAZ: Molecular pathway and disease therapy

The Yes-associated protein and its transcriptional coactivator with PDZ-binding motif (YAP/TAZ) are two homologous transcriptional coactivators that lie at the center of a key regulatory network of Hippo, Wnt, GPCR, estrogen, mechanical, and metabolism signaling. YAP/TAZ influences the expressions of downstream genes and proteins as well as enzyme activity in metabolic cycles, cell proliferation, inflammatory factor expression, and the transdifferentiation of fibroblasts into myofibroblasts. YAP/TAZ can also be regulated through epigenetic regulation and posttranslational modifications. Consequently, the regulatory function of these mechanisms implicates YAP/TAZ in the pathogenesis of metabolism-related diseases, atherosclerosis, fibrosis, and the delicate equilibrium between cancer progression and organ regeneration. As such, there arises a pressing need for thorough investigation of YAP/TAZ in clinical settings. In this paper, we aim to elucidate the signaling pathways that regulate YAP/TAZ and explore the mechanisms of YAP/TAZ-induce diseases and their potential therapeutic interventions. Furthermore, we summarize the current clinical studies investigating treatments targeting YAP/TAZ. We also address the limitations of existing research on YAP/TAZ and propose future directions for research. In conclusion, this review aims to provide fresh insights into the signaling mediated by YAP/TAZ and identify potential therapeutic targets to present innovative solutions to overcome the challenges associated with YAP/TAZ.

TLR4 predicts patient prognosis and immunotherapy efficacy in clear cell renal cell carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) constitutes the commonest kidney malignancy. Immunogenic cell death (ICD) is a type of regulated cell death (RCD), which sufficiently activates adaptive immunity. However, ICD's involvement in cancer development is unclear, as well as the associations of ICD effectors with ccRCC prognosis. Methods: RNA-sequencing expression profiles of ccRCC in The Cancer Genome Atlas (TCGA) and normal samples in Gene Expression Omnibus (GEO) were comprehensively investigated. Consensus clustering analysis was employed to determine subgroup members linked to ICD-related genes. Functional enrichment analysis was utilized for the examination of TLR4's biological role, and in vitro cellular assays were utilized for further confirmation. We also used Kaplan-Meier (KM) and Cox regression analyses to assess TLR4's prognostic value. Finally, "CIBERSORT" was employed for immune score evaluation. Results: The associations of ICD effectors with ccRCC prognosis were examined based on TCGA, and 12 genes showed upregulation in ccRCC tissue specimens. Meanwhile, ccRCC cases with upregulated ICD-related genes had increased overall survival. Among these ICD-related genes, TLR4 was selected for subsequent analysis. TLR4 was upregulated in ccRCC samples and independently predicted ccRCC. TLR4 also enhanced the proliferative, migratory and invasive abilities in cultured ccRCC cells. Moreover, TLR4 had close relationships with immune checkpoints and infiltrated immune cells. ccRCC cases with elevated TLR4 expression had prolonged overall survival, suggesting a prognostic value for TLR4. Finally, a pan-cancer analysis demonstrated TLR4 had differential expression in various malignancies in comparison with normal tissue samples. Conclusions: This study revealed prognostic values for ICD-associated genes, particularly TLR4, and experimentally validated the inducing effects of TLR4 on ccRCC progression in vitro. We also demonstrated the associations of TLR4 with immune cell infiltration, providing a novel strategy for prognostic evaluation and a novel therapeutic target in ccRCC.

Immune Transcriptional Response in Head Kidney Primary Cell Cultures Isolated from the Three Most Important Species in Chilean Salmonids Aquaculture

Fish cell culture is a common in vitro tool for studies in different fields such as virology, toxicology, pathology and immunology of fish. Fish cell cultures are a promising help to study how to diagnose and control relevant viral and intracellular bacterial infections in aquaculture. They can also be used for developing vaccines and immunostimulants, especially with the ethical demand aiming to reduce and replace the number of fish used in research. This study aimed to isolate head kidney primary cell cultures from three Chilean salmonids: Salmo salar, Oncorhynchus kisutch, and Oncorhynchus mykiss, and characterize the response to bacterial and viral stimuli by evaluating various markers of the innate and adaptive immune response. Specifically, the primary cell cultures of the head kidney from the three salmonids studied were cultured and exposed to two substances that mimic molecular patterns of different pathogens, i.e., Lipopolysaccharide (LPS) (bacterial) and Polyinosinic: polycytidylic acid (POLY I:C). Subsequently, we determined the mRNA expression profiles of the TLR-1, TLR-8, IgM, TLR-5, and MHC II genes. Head kidney primary cell cultures from the three species grown in vitro responded differently to POLY I:C and LPS. This is the first study to demonstrate and characterize the expression of immune genes in head kidney primary cell culture isolated from three salmonid species. It also indicates their potential role in developing immune responses as defense response agents and targets of immunoregulatory factors.

Transcriptome-wide analyses of early immune responses in lumpfish leukocytes upon stimulation with poly(I:C)

Background

Both bacterial and viral diseases are a major threat to farmed fish. As the antiviral immune mechanisms in lumpfish (Cyclopterus lumpus L.) are poorly understood, lumpfish leukocytes were stimulated with poly(I:C), a synthetic analog of double stranded RNA, which mimic viral infections, and RNA sequencing was performed.

Methods

To address this gap, we stimulated lumpfish leukocytes with poly(I:C) for 6 and 24 hours and did RNA sequencing with three parallels per timepoint. Genome guided mapping was performed to define differentially expressed genes (DEGs).

Results

Immune genes were identified, and transcriptome-wide analyses of early immune responses showed that 376 and 2372 transcripts were significantly differentially expressed 6 and 24 hours post exposure (hpe) to poly(I:C), respectively. The most enriched GO terms when time had been accounted for, were immune system processes (GO:0002376) and immune response (GO:0006955). Analysis of DEGs showed that among the most highly upregulated genes were TLRs and genes belonging to the RIG-I signaling pathway, including LGP2, STING and MX, as well as IRF3 and IL12A. RIG-I was not identified, but in silico analyses showed that genes encoding proteins involved in pathogen recognition, cell signaling, and cytokines of the TLR and RIG-I signaling pathway are mostly conserved in lumpfish when compared to mammals and other teleost species.

Conclusions

Our analyses unravel the innate immune pathways playing a major role in antiviral defense in lumpfish. The information gathered can be used in comparative studies and lay the groundwork for future functional analyses of immune and pathogenicity mechanisms. Such knowledge is also necessary for the development of immunoprophylactic measures for lumpfish, which is extensively cultivated for use as cleaner fish in the aquaculture for removal of sea lice from Atlantic salmon (Salmo salar L.).

Transcriptome Revealed the Macrophages Inflammatory Response Mechanism and NOD-like Receptor Characterization in Siberian Sturgeon (Acipenser baerii)

Nucleotide-binding and oligomerization domain-like receptors (NOD-like receptors, NLRs) can regulate the inflammatory response to eliminate pathogens and maintain the host's homeostasis. In this study, the head kidney macrophages of Siberian sturgeon were treated with lipopolysaccharide (LPS) to induce inflammation by evaluating the expression of cytokines. The high-throughput sequencing for macrophages after 12 h treatment showed that 1224 differentially expressed genes (DEGs), including 779 upregulated and 445 downregulated, were identified. DEGs mainly focus on pattern recognition receptors (PRRs) and the adaptor proteins, cytokines, and cell adhesion molecules. In the NOD-like receptor signaling pathway, multiple NOD-like receptor family CARD domains containing 3-like (NLRC3-like) were significantly downregulated, and pro-inflammatory cytokines were upregulated. Based on the transcriptome database, 19 NLRs with NACHT structural domains were mined and named in Siberian sturgeon, including 5 NLR-A, 12 NLR-C, and 2 other NLRs. The NLR-C subfamily had the characteristics of expansion of the teleost NLRC3 family and lacked the B30.2 domain compared with other fish. This study revealed the inflammatory response mechanism and NLRs family characterization in Siberian sturgeon by transcriptome and provided basic data for further research on inflammation in teleost.

Astragalus polysaccharide improves the growth, meat quality, antioxidant capacity and bacterial resistance of Furong crucian carp (Furong carp♀ × red crucian carp♂)

To evaluate the functional effects of APS (Astragalus polysaccharide) on Furong crucian carp, APS-supplemented diets (0.00 %, 0.05 %, 0.10 % and 0.15 %) were prepared and utilized in feeding experiment. The results showed that the 0.05 % APS group has the highest weight gain rate and specific growth rate, and the lowest feed coefficient rate. In addition, 0.05 % APS supplement could improve muscle elasticity, adhesiveness and chewiness. Moreover, the 0.15 % APS group had the highest spleen-somatic index and the 0.05 % group had the maximum intestinal villus length. 0.05 % and 0.10 % APS addition significantly increased T-AOC and CAT activities while MDA contents decreased in all APS groups. The plasma TNF-α levels in all APS groups significantly increased (P<0.05), and the 0.05 % group showed the highest TNF-α level in spleen. In APS addition groups, the tlr8, lgp2 and mda5 gene expressions were significantly elevated, while xbp1, caspase-2 and caspase-9 expressions decreased in uninfected and A. hydrophila-infected fish. Finally, higher survival rate and slower disease outbreak rate were observed in APS-supplemented groups after being infected by A. hydrophila. In conclusion, Furong crucian carp fed by APS-supplemented diets possesses elevated weight gain rate and specific growth rate, and improved meat quality, immunity and disease resistance.

Tea polyphenols, astaxanthin, and melittin can significantly enhance the immune response of juvenile spotted knifejaw (Oplegnathus punctatus)

The frequent occurrence of diseases seriously hampers the sustainable development of the spotted knifejaw (Oplegnathus punctatus) breeding industry. Our previous genome-wide scan and cross-species comparative genomic analysis revealed that the immune gene family (Toll-like receptors, TLR) members of O. punctatus underwent a significant contraction event (tlr1, tlr2, tlr14, tlr5, and tlr23). To address immune genetic contraction may result in reduced immunity, we investigated whether adding different doses (0, 200, 400, 600, and 800 mg/kg) of immune enhancers (tea polyphenols, astaxanthin, and melittin) to the bait after 30 days of continuous feeding could stimulate the immune response of O. punctatus. We found that the expression of tlr1, tlr14, tlr23 genes in immune organs (spleen and head kidney) was stimulated when tea polyphenols were added at 600 mg/kg. The tlr2 (400 mg/kg), tlr14 (200 mg/kg), tlr5 (200 mg/kg), and tlr23 (200 mg/kg) genes expression of intestine were elevated in the tea polyphenol group. When the addition of astaxanthin is 600 mg/kg, it can effectively stimulate the expression of tlr14 gene in immune organs (liver, spleen and head kidney). In the astaxanthin group, the expression of the genes tlr1 (400 mg/kg), tlr14 (600 mg/kg), tlr5 (400 mg/kg) and tlr23 (400 mg/kg) reached their highest expression in the intestine. Besides, the addition of 400 mg/kg of melittin can effectively induce the expression of tlr genes in the liver, spleen and head kidney, except the tlr5 gene. The tlr-related genes expression in the intestine was not significantly elevated in the melittin group. We hypothesize that the immune enhancers could enhance the immunity of O. punctatus by increasing the expression of tlr genes, and thereby leading to increased resistance to diseases. Meanwhile, our findings further demonstrated that significant increases in weight gain rate (WGR), visceral index (VSI), and feed conversion rate (FCR) were observed at 400 mg/kg, 200 mg/kg and 200 mg/kg of tea polyphenols, astaxanthin and melittin in the diet, respectively. Overall, our study provided valuable insights for future immunity enhancement and viral infection prevention in O. punctatus, as well as offered guidance for the healthy development of the O. punctatus breeding industry.

The acute inflammatory response of teleost fish

Acute inflammation is crucial to the immune responses of fish. The process protects the host from infection and is central to induction of subsequent tissue repair programs. Activation of proinflammatory signals reshapes the microenvironment within an injury/infection site, initiates leukocyte recruitment, promotes antimicrobial mechanisms and contributes to the resolution of inflammation. Inflammatory cytokines and lipid mediators are primary contributors to these processes. Uncontrolled or persistent induction results in delayed tissue healing. The kinetics by which inducers and regulators of acute inflammation exert their actions is essential for understanding the pathogenesis of fish diseases and identifying potential treatments. Although, a number of these are well-conserved across, others are not, reflecting the unique physiologies and life histories of members of this unique animal group.

The role of toll-like receptors (TLRs) and their therapeutic applications in endometrial cancer

Endometrial cancer (EC) is developed nations' most prevalent form of gynecologic cancer. Patients are frequently diagnosed with EC when the tumor is still limited to the uterus. Patients without tumor metastasis have a 5-year survival rate ranging from 80 to 90%; however, almost 16.8% of EC patients develop a metastatic form of the tumor. In the early stages of tumorigenesis, the immune system is able to identify aberrant cells as non-self, therefore providing the optimal pro-inflammatory microenvironment for the elimination of cancer cells. Although, chronic inflammation can be a crucial aspect of tumor development. Toll-like receptors (TLRs), as the main pattern recognition receptors (PRRs) in innate immunity, may stimulate an inflammatory response and provide cell survival in the tumor microenvironment (TME). TLRs are vital immunomodulators that may significantly impact the development of gynecologic malignancies. Therefore, TLR inhibitors are being researched for their possible benefits in treating gynecologic cancers. The aim of this study is to review the current knowledge in this field and provide some insight into the therapeutic potential of TLR inhibitors in EC.

Polystyrene microplastics induce myocardial inflammation and cell death via the TLR4/NF-κB pathway in carp

Microplastics (MPs) have attracted widespread attention as an emerging environmental pollutant. Especially in aquatic ecosystems, the harm of MPs to aquatic animals has increasingly become a severe environmental problem. In this study, we constructed a carp polystyrene microplastics (PS-MPs) exposure model to explore the damage and mechanism of PS-MPs exposure to carp myocardial tissue. The results of H&E, TUNEL, and AO/EB staining showed that PS-MPs exposure could induce inflammation, apoptosis, and necrosis in carp myocardial tissue and cardiomyocytes. In addition, our study explored the targeting relationship between PS-MPs and TLR4 and found that PS-MPs exposure could significantly increase the expression of TLR4 pathway-related factors. As the concentration of PS-MPs increased, the NF-κB pathway and inflammation-related factors increased dose-dependent. In addition, myocardial injury induced by exposure to PS-MPs was predominantly apoptotic, accompanied by necrosis. In short, our data suggest that PS-MPs cause damage to myocardial tissue via the TLR4\NF-κB pathway. The above findings enrich the theory of toxicological studies on PS-MPs and provide an essential reference for aquaculture.

Transcriptome analysis of liver, gill and intestine in rainbow trout (Oncorhynchus mykiss) symptomatically or asymptomatically infected with Vibrio anguillarum

Rainbow trout (Oncorhynchus mykiss), an important economic cold-water fish worldwide, is severely threatened by viruses and bacteria in the farming industry. The vibriosis outbreak has caused a significant setback to aquaculture. Vibrio anguillarum, one of the common disease-causing vibriosis associated with severe lethal vibriosis in aquaculture, infects fish mainly by adsorption and invasion of the skin, gills, lateral line and intestine. To investigate the defense mechanism of rainbow trout against the pathogen after infection with Vibrio anguillarum, trout were intraperitoneally injected by Vibrio anguillarum and divided into symptomatic group (SG) and asymptomatic group (AG) according to the phenotype. RNA-Seq technology was used to evaluate the transcriptional signatures of liver, gill and intestine of trout injected with Vibrio anguillarum (SG and AG) and corresponding control groups (CG(A) and CG(B)). The GO and KEGG enrichment analyses were used to investigate the mechanisms underlying the differences in susceptibility to Vibrio anguillarum. Results showed that in SG, immunomodulatory genes in the cytokine network were activated and tissue function-related genes were down-regulated, while apoptosis mechanisms were activated. However, AG responded to Vibrio anguillarum infection by activating complement related immune defenses, while metabolism and function related genes were up-regulated. Conclusively, a rapid and effective immune and inflammatory response can successfully defend Vibrio anguillarum infection. However, a sustained inflammatory response can lead to tissue and organ damage and cause death. Our results may provide a theoretical basis for breeding rainbow trout for disease resistance.

Proteotranscriptomic analyses reveal distinct interferon-beta signaling pathways and therapeutic targets in choroidal neovascularization

Aim

To investigate the molecular mechanism underlying the onset of choroidal neovascularization (CNV).

Methods

Integrated transcriptomic and proteomic analyses of retinas in mice with laser-induced CNV were performed using RNA sequencing and tandem mass tag. In addition, the laser-treated mice received systemic interferon-β (IFN-β) therapy. Measurements of CNV lesions were acquired by the confocal analysis of stained choroidal flat mounts. The proportions of T helper 17 (Th17) cells were determined by flow cytometric analysis.

Results

A total of differentially expressed 186 genes (120 up-regulated and 66 down-regulated) and 104 proteins (73 up-regulated and 31 down-regulated) were identified. The gene ontology and KEGG pathway analyses indicated that CNV was mainly associated with immune and inflammatory responses, such as cellular response to IFN-β and Th17 cell differentiation. Moreover, the key nodes of the protein-protein interaction network mainly involved up-regulated proteins, including alpha A crystallin and fibroblast growth factor 2, and were verified by Western blotting. To confirm the changes in gene expression, real-time quantitative PCR was performed. Furthermore, levels of IFN-β in both the retina and plasma, as measured by enzyme-linked immunosorbent assay (ELISA), were significantly lower in the CNV group than in the control group. IFN-β treatment significantly reduced CNV lesion size and promoted the proliferation of Th17 cells in laser-treated mice.

Conclusions

This study demonstrates that the occurrence of CNV might be associated with the dysfunction of immune and inflammatory processes and that IFN-β could serve as a potential therapeutic target.

Non-coding RNAs targeting NF-κB pathways in aquatic animals: A review

Nuclear factor-kappa B (NF-κB) pathways have a close relationship with many diseases, especially in terms of the regulation of inflammation and the immune response. Non-coding RNAs (ncRNAs) are a heterogeneous subset of endogenous RNAs that directly affect cellular function in the absence of proteins or peptide products; these include microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), etc. Studies on the roles of ncRNAs in targeting the NF-κB pathways in aquatic animals are scarce. A few research studies have confirmed detailed regulatory mechanisms among ncRNAs and the NF-κB pathways in aquatic animals. This comprehensive review is presented concerning ncRNAs targeting the NF-κB pathway in aquatic animals and provides new insights into NF-κB pathways regulatory mechanisms of aquatic animals. The review discusses new possibilities for developing non-coding-RNA-based antiviral applications in fisheries.