Immune Response and Apoptosis-Related Pathways Induced by Aeromonas schubertii Infection of Hybrid Snakehead (Channa maculata♀ × Channa argus♂)

Abstract

Aeromonas schubertii is the etiological pathogen of internal organ nodules in snakehead fish. Infections with A. schubertii produce a significant economic loss in aquaculture. Therefore, it is important to examine the immune mechanisms by which snakeheads defend against A. schubertii infection. In this study, we established a hybrid snakehead infection model by intraperitoneal injection of A. schubertii that produced internal organ nodules. The splenic immune response of infected fish was examined at the transcriptome level by Illumina-seq analysis. Results showed 14,796 differentially expressed genes (DEGs) following A. schubertii infection, including 4441 up-regulated unigenes and 10,355 down-regulated unigenes. KEGG analysis showed 2084 DEGs to be involved in 192 pathways, 14 of which were immune-related. Twelve DEGs were used to validate quantitative real-time PCR results with RNA-seq data. Time-course expression analysis of six genes demonstrated modulation of the snakehead immune response by A. schubertii. Furthermore, transcriptome analysis identified a substantial number of DEGs that were involved in the apoptosis signaling pathway. TUNEL analysis of infected spleens confirmed the presence of apoptotic cells. This study provided new information for a further understanding of the pathogenesis of A. schubertii in snakeheads, which can be used to prevent and possibly treat A. schubertii infections.

A novel defensin‐like peptide C‐13326 possesses protective effect against multidrug‐resistant Aeromonas schubertii in hybrid snakehead (Channa maculate ♀ × Channa argus ♂)

“…schubertii at the transcriptome level by Illumina-seq analysis and found that A. schubertii activated a variety of innate immune cytokines involved in immune regulation (Liu et al, 2021). We found that C-13326 peptide significantly down-regulated pro-inflammatory cytokine IL1, IL8, IL12 and TNFα in spleen of hybrid snakehead infected with A. schubertii.…”

“…Certain cytokine genes have been linked to the innate immune response, which of them are known to be important in protecting against pathogenic microorganisms in various fish species. A previous study has been conducted the spleen immune response of hybrid snakehead infected with A. schubertii at the transcriptome level by Illumina‐seq analysis and found that A. schubertii activated a variety of innate immune cytokines involved in immune regulation (Liu et al., 2021). We found that C‐13326 peptide significantly down‐regulated pro‐inflammatory cytokine IL1 , IL8 , IL12 and TNF‐α in spleen of hybrid snakehead infected with A. schubertii .…”

Histopathological characteristics of striped catfish (Pangasianodon hypophthalmus) in challenge with Edwardsiella ictaluri

“…Of all the organs inspected, the spleen had one of the worst injuries. Numerous researchers have noticed bacterial infection-induced cellular degeneration in the spleen (Mawdesley-Thomas, 1969;Ferguson & McCarthy, 1978;Huizinga et al, 1979;Liu et al, 2021). Wolke (1975) thought that severe hematopoietic and structural connective tissue necrosis of the spleen was the most prominent lesion.…”

“…Since hematopoiesis is one of the functions of the spleen (Grizzle & Rogers, 1976), injury or damage to the spleen could cause the inability to produce erythrocytes and leucocytes resulting in anemia and leucopenia. Histopathology of the liver, kidney, and spleen of naturally infected fish was validated with severe pathologies such as macrophage aggregation with hepatitis, degeneration of hematopoietic tissues, and granulomatous splenitis (Loch et al, 2017;Mamun et al, 2022). This was consistent with clinical manifestations of fish, including reduced response and appetite or stopped eating.…”

Prevalence and antibiotic resistance of Aeromonas schubertii causing internal white spot disease on snakehead fish, Channa striata, in the Mekong Delta, Vietnam

“…In addition, Latif‐Eugenín et al (2016) documented three isolates of A. schubertii isolated from mussels, which carried the aerA and lafA virulence genes and showed susceptibility to all antibiotics tested. In aquaculture, A. schubertii was identified as an emergent disease in aquaculture (e.g., Cao et al, 2021; Latif‐Eugenín et al, 2016; Liu et al, 2021; Talagrand‐Reboul et al, 2020). Thus, antibiotic therapies have been routinely used to manage this fish disease.…”