Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111139
Young-Bin Yu , A-Hyun Jo , Cheol Young Choi , Ju-Chan Kang , Jun-Hwan Kim
Crucian carp (Carassius carassius) were exposed to polyethylene microplastics (PE-MPs) at concentrations of 0, 4, 8, 16, 32, and 64 mg/L for two weeks. The experimental fish had a mean weight of 23.2 ± 3.1 g and a mean length of 12.1 ± 0.9 cm. Exposure to ≥32 mg/L PE-MPs caused significant increases in cortisol and HSP70 levels, indicating activation of endocrine and cellular stress responses. In contrast, immune parameters such as lysozyme activity and IgM concentrations were significantly reduced, demonstrating suppression of both innate and adaptive immune functions. Moreover, acetylcholinesterase (AChE) activity was significantly inhibited, reflecting impaired cholinergic neurotransmission and neurotoxicity. Integrated biomarker response (IBR) analysis revealed concentration-dependent alterations, while heatmap and principal component analyses (PCA) confirmed that PE-MPs predominantly induced stress-related physiological responses. Collectively, these findings demonstrate that exposure to ≥32 mg/L PE-MPs poses significant physiological and neuro-immunotoxic risks to C. carassius.
{"title":"Toxic effects of microplastic (polyethylene) exposure: Stress, immune responses and neurotoxicity in crucian carp, Carassius carassius","authors":"Young-Bin Yu , A-Hyun Jo , Cheol Young Choi , Ju-Chan Kang , Jun-Hwan Kim","doi":"10.1016/j.fsi.2026.111139","DOIUrl":"10.1016/j.fsi.2026.111139","url":null,"abstract":"<div><div>Crucian carp (<em>Carassius carassius</em>) were exposed to polyethylene microplastics (PE-MPs) at concentrations of 0, 4, 8, 16, 32, and 64 mg/L for two weeks. The experimental fish had a mean weight of 23.2 ± 3.1 g and a mean length of 12.1 ± 0.9 cm. Exposure to ≥32 mg/L PE-MPs caused significant increases in cortisol and HSP70 levels, indicating activation of endocrine and cellular stress responses. In contrast, immune parameters such as lysozyme activity and IgM concentrations were significantly reduced, demonstrating suppression of both innate and adaptive immune functions. Moreover, acetylcholinesterase (AChE) activity was significantly inhibited, reflecting impaired cholinergic neurotransmission and neurotoxicity. Integrated biomarker response (IBR) analysis revealed concentration-dependent alterations, while heatmap and principal component analyses (PCA) confirmed that PE-MPs predominantly induced stress-related physiological responses. Collectively, these findings demonstrate that exposure to ≥32 mg/L PE-MPs poses significant physiological and neuro-immunotoxic risks to <em>C. carassius</em>.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111139"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111134
Yuan Feng , Wenxing Li , Jiamei Liu , Huazhi Chen , Pan Qin , Jingqun Ao , Xinhua Chen
Midnolin has recently been shown to mediate ubiquitin-independent proteasomal degradation of nuclear substrates, yet its evolutionary origin and function in non-mammalian immunity remain largely unexplored. Here, we identify a Midnolin homolog in large yellow croaker (Larimichthys crocea). A key finding is that the origin of Midnolin can be traced back to placozoans, the simplest known animals whose emergence predates that of sponges. In L. crocea, Lcmidnolin expression was significantly upregulated in immune-related tissues upon stimulation with poly(I:C), a viral mimic, suggesting its responsiveness to viral-like signals. Confocal microscopy revealed nuclear localization of LcMidnolin. Functionally, overexpression of LcMidnolin suppressed poly(I:C)-induced activation of type I interferon (IFN) promoters and diminished antiviral gene expression. Consistent with this inhibitory effect, LcMidnolin overexpression impaired the cellular antiviral response, as reflected by increased viral gene expression and exacerbated cytopathic effects in cells infected with spring viremia of carp virus (SVCV). Our findings provide the first evolutionary and functional insights into Midnolin in a non-mammalian vertebrate, revealing its previously unrecognized role as a regulator of the type I IFN signaling pathway.
{"title":"Midnolin has an ancient origin and negatively regulates type I IFN response in teleost fish","authors":"Yuan Feng , Wenxing Li , Jiamei Liu , Huazhi Chen , Pan Qin , Jingqun Ao , Xinhua Chen","doi":"10.1016/j.fsi.2026.111134","DOIUrl":"10.1016/j.fsi.2026.111134","url":null,"abstract":"<div><div>Midnolin has recently been shown to mediate ubiquitin-independent proteasomal degradation of nuclear substrates, yet its evolutionary origin and function in non-mammalian immunity remain largely unexplored. Here, we identify a Midnolin homolog in large yellow croaker (<em>Larimichthys crocea</em>). A key finding is that the origin of Midnolin can be traced back to placozoans, the simplest known animals whose emergence predates that of sponges. In <em>L. crocea</em>, <em>Lcmidnolin</em> expression was significantly upregulated in immune-related tissues upon stimulation with poly(I:C), a viral mimic, suggesting its responsiveness to viral-like signals. Confocal microscopy revealed nuclear localization of <em>Lc</em>Midnolin. Functionally, overexpression of <em>Lc</em>Midnolin suppressed poly(I:C)-induced activation of type I interferon (IFN) promoters and diminished antiviral gene expression. Consistent with this inhibitory effect, <em>Lc</em>Midnolin overexpression impaired the cellular antiviral response, as reflected by increased viral gene expression and exacerbated cytopathic effects in cells infected with spring viremia of carp virus (SVCV). Our findings provide the first evolutionary and functional insights into Midnolin in a non-mammalian vertebrate, revealing its previously unrecognized role as a regulator of the type I IFN signaling pathway.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111134"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111144
Han Wang , Chun Liu , Anicet Philippe Mane Sany , Ziquan Yang , Jie Chen , Guodong Zheng , Shuming Zou
The blunt snout bream (Megalobrama amblycephala) is an economically important freshwater fish species. However, it is highly susceptible to Aeromonas hydrophila infection, especially in intensive pond aquaculture in China. Molecular marker-assisted selection provides an efficient approach for breeding disease-resistant varieties; however, the key genes or molecular markers linked to A. hydrophila resistance remain scarce in this species. A 436 differential SNP sites with disease-resistant were screened on basis of whole-genome resequencing. Then, a high-throughput genomic KASP genotyping technique was utilized to discover favorable genes and SNP sites associated with A. hydrophila resistance. A total of 46 KASP markers were successfully developed with an accuracy of 92 %. These markers were used to genotyping 120 blunt snout bream individuals. Through trait correlation analysis and general linear models (GLM), five SNPs significantly (P < 0.05) associated with resistance to A. hydrophila were identified and mapped to five candidate genes (btnl2, cfhr2, slc47a1, neu3, nlrp1). Survival rate of individuals carrying the dominant genotype demonstrated an average survival rate of 81.39 %, which represents a 69.35 % increase in comparison with that of 48 % in total population. This effect was validated in an external population of 100 fish. These findings identify key genetic markers associated with A. hydrophila resistance and provide a direction for elucidating the underlying molecular immune mechanisms, thus establishing a genetic foundation for future breeding strategies.
{"title":"Development and identification of KASP-SNP markers correlated with Aeromonas hydrophila resistance traits in blunt snout bream (Megalobrama amblycephala)","authors":"Han Wang , Chun Liu , Anicet Philippe Mane Sany , Ziquan Yang , Jie Chen , Guodong Zheng , Shuming Zou","doi":"10.1016/j.fsi.2026.111144","DOIUrl":"10.1016/j.fsi.2026.111144","url":null,"abstract":"<div><div>The blunt snout bream (<em>Megalobrama amblycephala</em>) is an economically important freshwater fish species. However, it is highly susceptible to <em>Aeromonas hydrophila</em> infection, especially in intensive pond aquaculture in China. Molecular marker-assisted selection provides an efficient approach for breeding disease-resistant varieties; however, the key genes or molecular markers linked to <em>A. hydrophila</em> resistance remain scarce in this species. A 436 differential SNP sites with disease-resistant were screened on basis of whole-genome resequencing. Then, a high-throughput genomic KASP genotyping technique was utilized to discover favorable genes and SNP sites associated with <em>A</em>. <em>hydrophila</em> resistance. A total of 46 KASP markers were successfully developed with an accuracy of 92 %. These markers were used to genotyping 120 blunt snout bream individuals. Through trait correlation analysis and general linear models (GLM), five SNPs significantly (<em>P</em> < 0.05) associated with resistance to <em>A</em>. <em>hydrophila</em> were identified and mapped to five candidate genes (<em>btnl2, cfhr2, slc47a1, neu3, nlrp1</em>). Survival rate of individuals carrying the dominant genotype demonstrated an average survival rate of 81.39 %, which represents a 69.35 % increase in comparison with that of 48 % in total population. This effect was validated in an external population of 100 fish. These findings identify key genetic markers associated with <em>A. hydrophila</em> resistance and provide a direction for elucidating the underlying molecular immune mechanisms, thus establishing a genetic foundation for future breeding strategies.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111144"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111125
Lu Wang , Bingke Wang , Jiaxiang Zhu , Qi Zhang , Yuxuan Cui , Huajuan Shi , Chunnuan Zhang
High-fat diets (HFD) exacerbate intestinal health risks in aquaculture. This study evaluated effects of dietary sulforaphane (SFN) supplementation on intestinal morphology, biochemistry, microbiota, and metabolism in Yellow River carp (Cyprinus carpio haematopterus) fed HFD. Five isoprotein diets diets were formulated: control (CN, 6 % lipid), HFD (12.29 % lipid), and HFD with 10 (HS10), 15 (HS15), or 20 (HS20) mg/kg SFN. Results demonstrated that HFD induced marked intestinal inflammation featuring villi deformation, oxidative stress, epithelial exfoliation, mitochondrial swelling, significantly elevated pro-inflammatory cytokines (TNF-α/IL-1β/IL-6; p < 0.05), and downregulated tight junction protein genes (Occludin/ZO-1/Claudin-3; p < 0.05), concomitant with microbial dysbiosis (Proteobacteria dominance>70 %, reduced Cetobacterium) and disrupted metabolic pathways (amino acid imbalance). SFN supplementation significantly enhanced antioxidant enzyme activities (SOD/CAT/GSH-Px, p < 0.05), peaking in HS15, which also exhibited minimized pro-inflammatory cytokines and maximized tight junction expression (p < 0.05). Furthermore, 16S rRNA gene sequencing of the gut microbiota indicated that SFN restored microbial homeostasis, notably by increasing the abundance of Cetobacterium. Metabolomic analysis based on KEGG enrichment revealed that these beneficial effects were associated with the activation of FoxO signaling, enhanced lysosomal function, and upregulation of coenzyme A biosynthesis. Critically, HS15 demonstrated optimal efficacy across all parameters. Therefore, 15 mg/kg SFN is identified as the optimal dose to ameliorate intestinal health in Yellow River carp, providing a theoretical basis for functional aquafeed development.
{"title":"Sulforaphane attenuates HFD-induced enteritis in yellow river carp by restoring immune homeostasis, repairing intestinal barrier, and modulating gut microbiota","authors":"Lu Wang , Bingke Wang , Jiaxiang Zhu , Qi Zhang , Yuxuan Cui , Huajuan Shi , Chunnuan Zhang","doi":"10.1016/j.fsi.2026.111125","DOIUrl":"10.1016/j.fsi.2026.111125","url":null,"abstract":"<div><div>High-fat diets (HFD) exacerbate intestinal health risks in aquaculture. This study evaluated effects of dietary sulforaphane (SFN) supplementation on intestinal morphology, biochemistry, microbiota, and metabolism in Yellow River carp (<em>Cyprinus carpio haematopterus</em>) fed HFD. Five isoprotein diets diets were formulated: control (CN, 6 % lipid), HFD (12.29 % lipid), and HFD with 10 (HS10), 15 (HS15), or 20 (HS20) mg/kg SFN. Results demonstrated that HFD induced marked intestinal inflammation featuring villi deformation, oxidative stress, epithelial exfoliation, mitochondrial swelling, significantly elevated pro-inflammatory cytokines (<em>TNF-α/IL-1β/IL-6</em>; <em>p</em> < 0.05), and downregulated tight junction protein genes (<em>Occludin/ZO-1/Claudin-3</em>; <em>p</em> < 0.05), concomitant with microbial dysbiosis (Proteobacteria dominance>70 %, reduced <em>Cetobacterium</em>) and disrupted metabolic pathways (amino acid imbalance). SFN supplementation significantly enhanced antioxidant enzyme activities (SOD/CAT/GSH-Px, <em>p</em> < 0.05), peaking in HS15, which also exhibited minimized pro-inflammatory cytokines and maximized tight junction expression (<em>p</em> < 0.05). Furthermore, 16S rRNA gene sequencing of the gut microbiota indicated that SFN restored microbial homeostasis, notably by increasing the abundance of <em>Cetobacterium</em>. Metabolomic analysis based on KEGG enrichment revealed that these beneficial effects were associated with the activation of FoxO signaling, enhanced lysosomal function, and upregulation of coenzyme A biosynthesis. Critically, HS15 demonstrated optimal efficacy across all parameters. Therefore, 15 mg/kg SFN is identified as the optimal dose to ameliorate intestinal health in Yellow River carp, providing a theoretical basis for functional aquafeed development.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111125"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111135
Feng Jia , Li Wei , Wei-Dan Jiang , Pei Wu , Yang Liu , Yao-Bin Ma , Hong-Yun Zhang , Xiao-Wan Jin , Hong-Mei Ren , Xiao-Qiu Zhou , Lin Feng
Bacterial infections compromise fish physiological homeostasis by impairing barrier function and metabolic organs, posing a persistent challenge in intensive aquaculture. Silymarin (SLM) is a plant-derived flavonoid complex obtained from Silybum marianum, widely recognized for its multifunctional pharmacological and bioactivity. However, its regulatory role under stress induced by bacterial pathogens in aquatic animals remains poorly understood. This study explored the impact and potential mechanisms of dietary SLM on intestinal barrier function and liver protection in juvenile grass carp. Fish (24.2 ± 0.1 g) were randomly assigned to six groups and fed diets containing 0, 20, 40, 60, 80, or 100 mg/kg SLM for 70 days. Subsequently, the fish were challenged with Aeromonas hydrophila (A. hydrophila) for 6 days. Optimal SLM supplementation (1) alleviated intestinal damage by upregulating tight junction proteins and downregulating myosin light chain kinase (MLCK); (2) reduced liver pro-inflammatory cytokines, inhibited lipopolysaccharide (LPS) translocation, and suppressed activation of the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling pathway; (3) mitigated liver inflammation by inhibiting the phosphorylation of key nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathway proteins and downregulating nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome components; (4) decreased liver oxidative stress while enhancing antioxidant capacity and improving liver function; and (5) modulated gene expression related to metabolic enzymes and transporters in the intestine and liver. Dietary SLM improved gut–liver health by supporting barrier function, reducing inflammation, and enhancing metabolic and antioxidant responses, indicating its promise for nutritional use in aquaculture.
{"title":"Dietary silymarin improves gut–liver health by enhancing intestinal barrier integrity and modulating TLR4/NF-κB and NLRP3-mediated inflammatory responses in Aeromonas hydrophila–infected grass carp","authors":"Feng Jia , Li Wei , Wei-Dan Jiang , Pei Wu , Yang Liu , Yao-Bin Ma , Hong-Yun Zhang , Xiao-Wan Jin , Hong-Mei Ren , Xiao-Qiu Zhou , Lin Feng","doi":"10.1016/j.fsi.2026.111135","DOIUrl":"10.1016/j.fsi.2026.111135","url":null,"abstract":"<div><div>Bacterial infections compromise fish physiological homeostasis by impairing barrier function and metabolic organs, posing a persistent challenge in intensive aquaculture. Silymarin (SLM) is a plant-derived flavonoid complex obtained from <em>Silybum marianum</em>, widely recognized for its multifunctional pharmacological and bioactivity. However, its regulatory role under stress induced by bacterial pathogens in aquatic animals remains poorly understood. This study explored the impact and potential mechanisms of dietary SLM on intestinal barrier function and liver protection in juvenile grass carp. Fish (24.2 ± 0.1 g) were randomly assigned to six groups and fed diets containing 0, 20, 40, 60, 80, or 100 mg/kg SLM for 70 days. Subsequently, the fish were challenged with <em>Aeromonas hydrophila</em> (<em>A. hydrophila</em>) for 6 days. Optimal SLM supplementation (1) alleviated intestinal damage by upregulating tight junction proteins and downregulating myosin light chain kinase (MLCK); (2) reduced liver pro-inflammatory cytokines, inhibited lipopolysaccharide (LPS) translocation, and suppressed activation of the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling pathway; (3) mitigated liver inflammation by inhibiting the phosphorylation of key nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathway proteins and downregulating nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome components; (4) decreased liver oxidative stress while enhancing antioxidant capacity and improving liver function; and (5) modulated gene expression related to metabolic enzymes and transporters in the intestine and liver. Dietary SLM improved gut–liver health by supporting barrier function, reducing inflammation, and enhancing metabolic and antioxidant responses, indicating its promise for nutritional use in aquaculture.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111135"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111140
Yizhong Lu , Shijie Wang , Yuezong Xu , Bo Tang , Guanyu Chen , Jianguo Su , Chunrong Yang
Grass carp (Ctenopharyngodon idella) is frequently threatened by hemorrhagic disease caused by grass carp reovirus (GCRV) infection in aquaculture. Vaccination represents a crucial strategy for preventing this infectious disease, where adjuvants play a pivotal role in enhancing vaccine efficacy. This study evaluated the chemokine CXCL20a as a molecular adjuvant to boost the immunogenicity of an inactivated GCRV vaccine. A CXCL20a fusion protein (rC20) was prepared and purified, and a tag-free form (Tf-rC20) was obtained after TrxA tag removal. Five experimental groups were established: PBS control, vaccine alone, rC20 alone, and vaccine combined with rC20 and Tf-rC20 in separate groups. The vaccine-alone group showed a 60 % survival rate, which increased to 74 % and 78 % in the Vac + rC20 and Vac + Tf-rC20 groups, respectively. Tf-rC20 showed slightly higher efficacy than rC20, although the difference was limited. Viral load quantification and splenic histopathology further confirmed that combined immunization suppressed viral replication and alleviated tissue damage. Serum immune parameters analyses revealed that combined immunization significantly enhanced the activities of lysozyme, total superoxide dismutase, and complement component C3, suggesting a potentiation of non-specific immunity. qRT-PCR results showed significant upregulation of immune-related genes, including IFN1, IL-6, Mx2, and IgM, in immune tissues, indicating that CXCL20a promoted both innate and adaptive immune responses. These results collectively demonstrate that the recombinant CXCL20a protein, functioning as a molecular adjuvant, can synergize with the inactivated vaccine to significantly enhance protective immunity against GCRV in grass carp, providing a promising candidate for the development of novel adjuvants in fish vaccines.
{"title":"CXCL20a promotes the immune protection of an inactivated vaccine against grass carp reovirus infection in grass carp (Ctenopharyngodon idella)","authors":"Yizhong Lu , Shijie Wang , Yuezong Xu , Bo Tang , Guanyu Chen , Jianguo Su , Chunrong Yang","doi":"10.1016/j.fsi.2026.111140","DOIUrl":"10.1016/j.fsi.2026.111140","url":null,"abstract":"<div><div>Grass carp (<em>Ctenopharyngodon idella</em>) is frequently threatened by hemorrhagic disease caused by grass carp reovirus (GCRV) infection in aquaculture. Vaccination represents a crucial strategy for preventing this infectious disease, where adjuvants play a pivotal role in enhancing vaccine efficacy. This study evaluated the chemokine CXCL20a as a molecular adjuvant to boost the immunogenicity of an inactivated GCRV vaccine. A CXCL20a fusion protein (rC20) was prepared and purified, and a tag-free form (Tf-rC20) was obtained after TrxA tag removal. Five experimental groups were established: PBS control, vaccine alone, rC20 alone, and vaccine combined with rC20 and Tf-rC20 in separate groups. The vaccine-alone group showed a 60 % survival rate, which increased to 74 % and 78 % in the Vac + rC20 and Vac + Tf-rC20 groups, respectively. Tf-rC20 showed slightly higher efficacy than rC20, although the difference was limited. Viral load quantification and splenic histopathology further confirmed that combined immunization suppressed viral replication and alleviated tissue damage. Serum immune parameters analyses revealed that combined immunization significantly enhanced the activities of lysozyme, total superoxide dismutase, and complement component C3, suggesting a potentiation of non-specific immunity. qRT-PCR results showed significant upregulation of immune-related genes, including IFN1, IL-6, Mx2, and IgM, in immune tissues, indicating that CXCL20a promoted both innate and adaptive immune responses. These results collectively demonstrate that the recombinant CXCL20a protein, functioning as a molecular adjuvant, can synergize with the inactivated vaccine to significantly enhance protective immunity against GCRV in grass carp, providing a promising candidate for the development of novel adjuvants in fish vaccines.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111140"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111138
Tianyu Wang , Peng Lin , Yilei Wang , Luis O.B. Afonso , Jianjun Feng
Suppressor of cytokine signaling 1 (SOCS1) is a pivotal negative regulator of cytokine-mediated signaling in mammals, yet its role in teleost fish immunity remains poorly understood. In this study, we cloned and characterized the full-length SOCS1 cDNA from Japanese eel (Anguilla japonica), which encodes a 203-amino acid protein containing a conserved SH2 domain and SOCS box. Phylogenetic analysis placed AjSOCS1 within the teleost clade, showing high conservation with other vertebrate SOCS1 homologs. AjSOCS1 was ubiquitously expressed across tissues, with the highest levels in intestine and immune-related organs. Its transcription was significantly induced both in vivo (lipopolysaccharide [LPS], polyinosinic–polycytidylic acid [poly(I:C)], Aeromonas hydrophila) and in vitro (pathogen-associated molecular patterns [PAMPs] and bacterial infection), highlighting responsiveness to bacterial and viral stimuli. Subcellular localization analysis demonstrated that AjSOCS1 is cytoplasmic, consistent with its role in intracellular signaling regulation. Functional assays using a dual-luciferase reporter system revealed that AjSOCS1 strongly suppressed NF-κB activation under basal conditions, as well as during MyD88-, LPS-, and poly(I:C)-induced stimulation, and overexpression of AjSOCS1 resulted in coordinated downregulation of NF-κB subunits and downstream inflammatory and antimicrobial genes. Together, these findings provide the first functional evidence that SOCS1 in Japanese eel acts as a negative regulator of NF-κB signaling, thereby extending the known repertoire of SOCS1 activity in fish. This study not only enriches comparative immunology of SOCS proteins but also has potential implications for controlling excessive inflammation and improving disease resistance in aquaculture.
{"title":"Japanese eel SOCS1 suppresses MyD88-mediated NF-κB activation: implications for negative regulation of innate immunity in teleosts","authors":"Tianyu Wang , Peng Lin , Yilei Wang , Luis O.B. Afonso , Jianjun Feng","doi":"10.1016/j.fsi.2026.111138","DOIUrl":"10.1016/j.fsi.2026.111138","url":null,"abstract":"<div><div>Suppressor of cytokine signaling 1 (SOCS1) is a pivotal negative regulator of cytokine-mediated signaling in mammals, yet its role in teleost fish immunity remains poorly understood. In this study, we cloned and characterized the full-length SOCS1 cDNA from Japanese eel (<em>Anguilla japonica</em>), which encodes a 203-amino acid protein containing a conserved SH2 domain and SOCS box. Phylogenetic analysis placed <em>Aj</em>SOCS1 within the teleost clade, showing high conservation with other vertebrate SOCS1 homologs. <em>Aj</em>SOCS1 was ubiquitously expressed across tissues, with the highest levels in intestine and immune-related organs. Its transcription was significantly induced both <em>in vivo</em> (lipopolysaccharide [LPS], polyinosinic–polycytidylic acid [poly(I:C)], <em>Aeromonas hydrophila</em>) and <em>in vitro</em> (pathogen-associated molecular patterns [PAMPs] and bacterial infection), highlighting responsiveness to bacterial and viral stimuli. Subcellular localization analysis demonstrated that <em>Aj</em>SOCS1 is cytoplasmic, consistent with its role in intracellular signaling regulation. Functional assays using a dual-luciferase reporter system revealed that <em>Aj</em>SOCS1 strongly suppressed NF-κB activation under basal conditions, as well as during MyD88-, LPS-, and poly(I:C)-induced stimulation, and overexpression of <em>Aj</em>SOCS1 resulted in coordinated downregulation of NF-κB subunits and downstream inflammatory and antimicrobial genes. Together, these findings provide the first functional evidence that SOCS1 in Japanese eel acts as a negative regulator of NF-κB signaling, thereby extending the known repertoire of SOCS1 activity in fish. This study not only enriches comparative immunology of SOCS proteins but also has potential implications for controlling excessive inflammation and improving disease resistance in aquaculture.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111138"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111142
Jianhua Feng , Yafang Wang , Wenji Huang , Dawei Xie , Yinghao Huang , Xinran Tao , Tiantian Zhang , Haixia Wu , Jun Zou , Junya Wang
Cullin-RING ligases (CRLs) constitute the most diverse E3 ligase family in the ubiquitin-proteasome system, yet their antiviral roles in bony fish remain poorly understood. Here, we identify the catalytic cores of CRLs, the RING-box proteins RBX1 and RBX2, as key modulators of antiviral signaling in cyprinid fish. Phylogenetic and structural analyses revealed that Rbx1 and Rbx2 are highly conserved and widely expressed, with preferential enrichment in primordial germ and immune-related cells. Upon infection with grass carp reovirus (GCRV) or spring viremia of carp virus (SVCV) in cyprinid fish, Rbxs were rapidly induced in vivo and in vitro. RBX1 and RBX2 synergistically promote viral replication by directly interacting with interferon regulatory factors (IRF) 3 and IRF7 and facilitating their ubiquitin-mediated regulation. Together, our findings uncover RBX1 and RBX2 as evolutionarily conserved negative regulators of fish innate immunity and provide mechanistic insight into the ubiquitin-mediated control of interferon homeostasis across vertebrates.
{"title":"RBX1 and RBX2 promote GCRV replication in grass carp (Ctenopharyngodon idella)","authors":"Jianhua Feng , Yafang Wang , Wenji Huang , Dawei Xie , Yinghao Huang , Xinran Tao , Tiantian Zhang , Haixia Wu , Jun Zou , Junya Wang","doi":"10.1016/j.fsi.2026.111142","DOIUrl":"10.1016/j.fsi.2026.111142","url":null,"abstract":"<div><div>Cullin-RING ligases (CRLs) constitute the most diverse E3 ligase family in the ubiquitin-proteasome system, yet their antiviral roles in bony fish remain poorly understood. Here, we identify the catalytic cores of CRLs, the RING-box proteins RBX1 and RBX2, as key modulators of antiviral signaling in cyprinid fish. Phylogenetic and structural analyses revealed that <em>Rbx1</em> and <em>Rbx2</em> are highly conserved and widely expressed, with preferential enrichment in primordial germ and immune-related cells. Upon infection with grass carp reovirus (GCRV) or spring viremia of carp virus (SVCV) in cyprinid fish, <em>Rbxs</em> were rapidly induced <em>in vivo</em> and <em>in vitro</em>. RBX1 and RBX2 synergistically promote viral replication by directly interacting with interferon regulatory factors (IRF) 3 and IRF7 and facilitating their ubiquitin-mediated regulation. Together, our findings uncover RBX1 and RBX2 as evolutionarily conserved negative regulators of fish innate immunity and provide mechanistic insight into the ubiquitin-mediated control of interferon homeostasis across vertebrates.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111142"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111141
Dayanne Carla Fernandes , Silas Fernandes Eto , Leo Kei Iwai , Monica Lopes-Ferreira , Isabela de Oliveira Cavalcante Pimentel , Luiz Roberto Sardinha , Ismael Feitosa Lima , Denise V. Tambourgi
The genus Bitis, especially the species Bitis arietans, significantly contributes to snakebite incidents in Africa, causing a range of serious medical conditions. This study aimed to explore the pathological mechanisms underlying envenomations by B. arietans using zebrafish (Danio rerio) as a model organism. Blood samples were collected at 3- and 6-h post-envenomation, followed by plasma analysis through mass spectrometry. Key findings indicated that B. arietans venom caused a hemolytic effect leading to acute severe anemia by 6 h post-envenomation. A hematopoietic response was also observed, characterized by an increase in precursor blood cells and leukocytosis with elevated myelomonocytic cell counts. Mass spectrometry analysis identified 558 plasma proteins with differential abundance between the experimental groups, many of which play crucial roles in biological processes such as immune response, hemostasis, coagulation cascade, complement system activation, neutrophil degranulation, and oxidative stress regulation. Additionally, proteins associated with cellular extravasation and regulatory functions were detected, correlating with histopathological lesions observed locally and indicating systemic effects of envenomation affecting vital organs such as the kidneys, heart, liver, and gills. Our results suggest that the plasma protein profile identified may serve as potential biomarkers for assessing lesions resulting from B. arietans envenomation. Overall, these findings enhance our understanding of the toxic impacts of B. arietans venom and underscore the utility of zebrafish as a model for further research into snakebite pathophysiology.
{"title":"Zebrafish as a translational model for Bitis arietans envenomation: Integrative proteomic and histopathological insights","authors":"Dayanne Carla Fernandes , Silas Fernandes Eto , Leo Kei Iwai , Monica Lopes-Ferreira , Isabela de Oliveira Cavalcante Pimentel , Luiz Roberto Sardinha , Ismael Feitosa Lima , Denise V. Tambourgi","doi":"10.1016/j.fsi.2026.111141","DOIUrl":"10.1016/j.fsi.2026.111141","url":null,"abstract":"<div><div>The genus Bitis, especially the species <em>Bitis arietans</em>, significantly contributes to snakebite incidents in Africa, causing a range of serious medical conditions. This study aimed to explore the pathological mechanisms underlying envenomations by <em>B. arietans</em> using zebrafish (<em>Danio rerio</em>) as a model organism. Blood samples were collected at 3- and 6-h post-envenomation, followed by plasma analysis through mass spectrometry. Key findings indicated that <em>B. arietans</em> venom caused a hemolytic effect leading to acute severe anemia by 6 h post-envenomation. A hematopoietic response was also observed, characterized by an increase in precursor blood cells and leukocytosis with elevated myelomonocytic cell counts. Mass spectrometry analysis identified 558 plasma proteins with differential abundance between the experimental groups, many of which play crucial roles in biological processes such as immune response, hemostasis, coagulation cascade, complement system activation, neutrophil degranulation, and oxidative stress regulation. Additionally, proteins associated with cellular extravasation and regulatory functions were detected, correlating with histopathological lesions observed locally and indicating systemic effects of envenomation affecting vital organs such as the kidneys, heart, liver, and gills. Our results suggest that the plasma protein profile identified may serve as potential biomarkers for assessing lesions resulting from <em>B. arietans</em> envenomation. Overall, these findings enhance our understanding of the toxic impacts of <em>B. arietans</em> venom and underscore the utility of zebrafish as a model for further research into snakebite pathophysiology.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111141"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.fsi.2026.111137
Zihao Yan , Jingjing Lu , Yuesi Zhou , Liang Zhao , Ding Li , Huining Jia , Ayqeqan Nurmamat , Min Xiu , Shuyuan Zhang , Ruyu Zhuang , Ya Pang , Tiesong Li , Feng Sun , Yinglun Han
Jawless vertebrates offer critical insights into the evolutionary origins of adaptive immunity due to their unique phylogenetic position among chordates. However, the convergent evolution of adaptive immunity between jawless and jawed vertebrates remains incompletely understood. In this study, we characterized cytidine deaminases (CDAs), ancestral members of the AID/APOBEC deaminase family, in the lamprey Lethenteron reissneri. Functional analyses demonstrated that Lr-CDA1 exhibits in vivo activity comparable to activation-induced cytidine deaminase (AID) in jawed vertebrates. Loss of Lr-CDA1 disrupted the assembly of the three types of variable lymphocyte receptors (VLRs), with the strongest effect observed for VLRB. Within the germline VLR (gVLR) loci of Lethenteron reissneri, we identified CDA-associated regulatory regions that are required for proper VLR assembly and diversification. These regions were specifically bound by Lr-CDAs, and their repression resulted in a marked downregulation of VLRB expression. Collectively, our findings indicate that lampreys possess a CDA-mediated VLR rearrangement mechanism that acts on germline VLRs to regulate their assembly, maturation, and diversification. Moreover, the association of Lr-CDAs with tumorigenesis- and chromosomal translocation-related genes highlights an ancient molecular link between immune diversification and genome instability.
{"title":"AID/APOBEC-like cytidine deaminases are important mediators of VLR-based adaptive immunity in lampreys","authors":"Zihao Yan , Jingjing Lu , Yuesi Zhou , Liang Zhao , Ding Li , Huining Jia , Ayqeqan Nurmamat , Min Xiu , Shuyuan Zhang , Ruyu Zhuang , Ya Pang , Tiesong Li , Feng Sun , Yinglun Han","doi":"10.1016/j.fsi.2026.111137","DOIUrl":"10.1016/j.fsi.2026.111137","url":null,"abstract":"<div><div>Jawless vertebrates offer critical insights into the evolutionary origins of adaptive immunity due to their unique phylogenetic position among chordates. However, the convergent evolution of adaptive immunity between jawless and jawed vertebrates remains incompletely understood. In this study, we characterized cytidine deaminases <em>(CDAs</em>), ancestral members of the AID/APOBEC deaminase family, in the lamprey <em>Lethenteron reissneri</em>. Functional analyses demonstrated that <em>Lr-</em>CDA1 exhibits in vivo activity comparable to activation-induced cytidine deaminase (AID) in jawed vertebrates. Loss of <em>Lr-CDA1</em> disrupted the assembly of the three types of variable lymphocyte receptors (VLRs), with the strongest effect observed for VLRB. Within the germline <em>VLR</em> (<em>gVLR</em>) loci of <em>Lethenteron reissneri</em>, we identified CDA-associated regulatory regions that are required for proper <em>VLR</em> assembly and diversification. These regions were specifically bound by <em>Lr-</em>CDAs, and their repression resulted in a marked downregulation of VLRB expression. Collectively, our findings indicate that lampreys possess a CDA-mediated <em>VLR</em> rearrangement mechanism that acts on germline <em>VLRs</em> to regulate their assembly, maturation, and diversification. Moreover, the association of <em>Lr</em>-CDAs with tumorigenesis- and chromosomal translocation-related genes highlights an ancient molecular link between immune diversification and genome instability.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111137"},"PeriodicalIF":3.9,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146009490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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