RESUMO
This study examined the effectiveness of a DNA vaccine for S. agalactiae that was delivered by mannose-based polyethyleneimine (Man-PEI). The results showed that Man-PEI/pcDNA-Sip stimulated a higher serum antibody titer compared to control or other vaccine groups (p < 0.05). Additionally, it induced higher expression of immune-related genes, and increased activities of superoxide dismutase (SOD), acid phosphatase (ACP) and alkaline phosphatase (AKP). Furthermore, the Man-PEI/pcDNA-Sip group showed an improved relative percent survival (RPS) of 85.71%. These results demonstrate the potential value of Man-PEI as a vaccine delivery vehicle, and suggest that it can be effective in boosting the immune protective rate induced by pcDNA-Sip vaccines.
Assuntos
Ciclídeos , Doenças dos Peixes , Infecções Estreptocócicas , Vacinas Estreptocócicas , Vacinas de DNA , Animais , Polietilenoimina/farmacologia , Streptococcus agalactiae , Imunidade , Doenças dos Peixes/prevenção & controle , Infecções Estreptocócicas/prevenção & controle , Infecções Estreptocócicas/veterináriaRESUMO
Substance P (SP) is a neuropeptide that involves in a wide variety of physiological and pathological events, mainly exerts its roles by neurokinin 1 receptor (NK1R), also modulates immune function. However, the roles of SP during immune response to acute bacterial infection of Nile tilapia (Oreochromis niloticus) remain unclear. In this study, the gene of SP precursor (tachykinin precursor 1, TAC1) and the gene of SP receptor (NK1R) from Nile tilapia were identified, and the roles of SP during an acute bacterial infection in a warm water environment were investigated. On-TAC1(Oreochromis niloticus-TAC1) contains conservative SP & NKA peptide sequences and On-NK1R contains seven conservative transmembrane domains. Their transcriptional levels were most abundant in brain and the On-TAC1 transcripts can be induced in the tilapia challenged with Streptococcus agalactiae. Furthermore, the experimental results revealed that On-SP could promote pyroptosis, suppress inflammation, and improve survival rate during acute bacterial infection. The present data lays a theoretical foundation to further elucidate the mechanism of SP protecting fish against pathogens.
Assuntos
Ciclídeos , Doenças dos Peixes , Infecções Estreptocócicas , Animais , Proteínas de Peixes , Streptococcus agalactiae/fisiologia , Substância PRESUMO
α-Melanocyte-stimulating hormone (α-MSH) is a well-studied neuropeptide controlling skin and hair color. Besides, numerous immunomodulation roles of α-MSH were recorded in humans and mice. However, the regulatory effects of α-MSH in teleost immunity haven't been well elucidated. In this study, several precursor molecules of α-MSH (POMCs) and its receptors (MCRs) in Nile tilapia (Oreochromis niloticus) were characterized, and their expression characteristics and specific functions on antibacterial immunity were determined. Overall, POMCs and MCRs were principally detected in the brain, skin, and liver, and were remarkably promoted post Streptococcus agalactiae infection. However, tiny POMCs and MCRs were observed in tilapia immune organs (head kidney and spleen) or lymphocytes, and no evident immunomodulation effect was detected in vitro. Moreover, the in vivo challenge experiments revealed that α-MSH protects tilapia from bacterial infection by regulating responses in the brain and intestine. This study lays theoretical data for a deeper comprehension of the immunomodulation mechanisms of teleost α-MSH and the evolutional process of the vertebrate melanocortin system.
Assuntos
Doenças dos Peixes , Imunomodulação , Infecções Estreptocócicas , Tilápia , alfa-MSH , Animais , alfa-MSH/metabolismo , Sequência de Aminoácidos , Antibacterianos , Ciclídeos/imunologia , Ciclídeos/microbiologia , Doenças dos Peixes/imunologia , Doenças dos Peixes/microbiologia , Proteínas de Peixes/química , Regulação da Expressão Gênica , Imunomodulação/fisiologia , Infecções Estreptocócicas/veterinária , Streptococcus agalactiae/fisiologia , Tilápia/imunologia , Tilápia/microbiologiaRESUMO
Pyroptosis is an inflammatory and programmed cell death initiated by the formation of the inflammasome, which consists of NLR, ASC, and Caspase. Pyroptosis has received growing attention due to its association with innate immunity and various diseases. However, the involvement and induction of the NLRCs and pyroptosis-related genes in fish immunity remain poorly studied. In this study, several NLRCs and pyroptosis-related genes in Nile tilapia (Oreochromis niloticus) were identified and characterized. Their involvement in bacterial infection and expression profiles in Nile tilapia lymphocyte responses were also assessed. Overall, three NLRC members (NOD1, NOD2, and NLRC3) and five pyroptosis-related genes (ASC1, Caspase1, Gsdme, NLRP3, and NLRP14) in Nile tilapia were cloned and characterized. The transcript levels of these molecules were broadly distributed in various tissues with comparatively high expression in the gills, intestine, and spleen. Their transcripts were also induced during Streptococcus agalactiae or Aeromonas hydrophila infection. Moreover, they were primarily expressed in T cells, NCCs, and Mo/Mφ and showed antibacterial and partially antiviral responses. The present study lays a theoretical foundation for further investigation of the pyroptosis mechanisms in fish as well as the evolution of the antiviral roles of pyroptosis in vertebrates.
Assuntos
Ciclídeos , Doenças dos Peixes , Infecções Estreptocócicas , Animais , Antibacterianos , Antivirais , Caspases/genética , Proteínas de Peixes , Regulação da Expressão Gênica , Imunidade Inata/genética , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Piroptose/genética , Infecções Estreptocócicas/veterinária , Streptococcus agalactiae/fisiologiaRESUMO
Vasoactive intestinal peptide (VIP), a member of secretin/glucagon family, is involved in a variety of biological activities such as gut motility, immune responses, and carcinogenesis. In this study, the VIP precursor gene (On-VIP) and its receptor gene VIPR1 (On-VIPR1) were identified from Nile tilapia (Oreochromis niloticus), and the functions of On-VIP in the immunomodulation of Nile tilapia against bacterial infection were investigated and characterized. On-VIP and On-VIPR1 contain a 450 bp and a 1326 bp open reading frame encoding deduced protein of 149 and 441 amino acids, respectively. Simultaneously, the transcript of both On-VIP and On-VIPR1 were highly expressed in the intestine and sharply induced by Streptococcus agalatiae. Moreover, the positive signals of On-VIP and On-VIPR1 were detected in the longitudinal muscle layer and mucosal epithelium of intestine, respectively. Furthermore, both in vitro and in vivo experiments indicated several immune functions of On-VIP, including reduction of P65, P38, MyD88, STAT3, and AP1, upregulation of CREB and CBP, and suppression of inflammation. Additionally, in vivo experiments proved that On-VIP could protect Nile tilapia from bacterial infection and promote apoptosis and pyroptosis. These data lay a theoretical basis for further understanding of the mechanism of VIP guarding bony fish against bacterial infection.
Assuntos
Ciclídeos , Doenças dos Peixes , Infecções Estreptocócicas , Animais , Peptídeo Intestinal Vasoativo/genética , Peptídeo Intestinal Vasoativo/metabolismo , Infecções Estreptocócicas/prevenção & controle , Infecções Estreptocócicas/veterinária , Streptococcus agalactiae , Doenças dos Peixes/genética , Doenças dos Peixes/prevenção & controle , Regulação da Expressão GênicaRESUMO
BACKGROUD: Streptococcus agalactiae is a common colonizer of the rectovaginal tract and lead to infectious diseases of neonatal and non-pregnant adults, which also causes infectious disease in fish and a zoonotic risk as well. Lysine crotonylation (Kcr) is a kind of histone post-translational modifications discovered in 2011. In yeast and mammals, Kcr function as potential enhancers and promote gene expression. However, lysine crotonylation in S. agalactiae has not been studied yet. METHODS: In this study, the crotonylation profiling of fish pathogen, S. agalactiae was investigated by combining affinity enrichment with LC MS/MS. The Kcr modification of several selected proteins were further validated by Western blotting. RESULTS: In the present study, we conducted the proteome-wide profiling of Kcr in S. agalactiae and identified 241 Kcr sites from 675 screened proteins for the first time. Bioinformatics analysis showed that 164 sequences were matched to a total of six definitively conserved motifs, and many of them were significantly enriched in metabolic processes, cellular process, and single-organism processes. Moreover, four crotonylation modified proteins were predicted as virulence factors or to being part of the quorum sensing system PTMs on bacteria. The data are available via ProteomeXchange with identifier PXD026445. CONCLUSIONS: These data provide a promising starting point for further functional research of crotonylation in bacterial virulence in S. agalactiae.
RESUMO
Serotonin (5-hydroxytryptamine) is a well-known neurotransmitter affecting emotion, behavior, and cognition. Additionally, numerous immunomodulatory functions of serotonin have been discovered in mammals. However, the regulatory role of the serotonin system in fish immunity remains unclear. In this study, various serotonergic markers in Nile tilapia (Oreochromis niloticus) were identified and characterized. The involvement of the serotonin system during bacterial infection was investigated. Moreover, the expression characteristics and specific functions of serotonergic markers within Nile tilapia immune cells were also assessed. Overall, 22 evolutionarily conserved serotonergic marker genes in Nile tilapia were cloned and characterized. Transcriptional levels of these molecules were most abundant in the brain, and their transcripts were induced during Streptococcus agalactiae infection. Nevertheless, few serotonergic markers exist on Nile tilapia immune cells, and no distinct immunomodulation effect was observed during an immune response. The present study lays a theoretical foundation for further investigation of the immunological mechanisms in fish as well as the evolution of the serotonin system in animals.
Assuntos
Ciclídeos , Doenças dos Peixes , Sequência de Aminoácidos , Animais , Proteínas de Peixes/genética , Regulação da Expressão Gênica , Imunidade , Imunomodulação , Mamíferos/metabolismo , Serotonina , Streptococcus agalactiae/fisiologiaRESUMO
C-reactive protein (CRP) is an acute-phase protein that can be used as an early diagnostic marker for inflammation, which is also an evolutionarily conserved protein and has been identified from arthropods to mammals. However, the roles of CRP during the immune response of Nile tilapia (Oreochromis niloticus) remain unclear. In this study, a CRP gene from Nile tilapia (On-CRP) was identified, and its roles in response to bacterial infection were investigated in vivo or in vitro. On-CRP was found to contain an open reading frame of 675 bp, encoding a polypeptide of 224 amino acids with the conservative pentraxin domain. On-CRP shares more than 50% of its identity with other fish species, and 30% of its identity with mammals. The transcriptional level of On-CRP was most abundant in the liver and its transcripts can be remarkably induced following Streptococcus agalactiae and Aeromonas hydrophila infection. Furthermore, in vitro analysis indicated that the recombinant protein of On-CRP improved phagocytic activity of monocytes/macrophages, and possessed a bacterial agglutination activity in a calcium-dependent manner. Both in vivo and in vitro experiments indicated that On-CRP could promote inflammation and activate the complement pathway. However, a direct relationship between CRP and several immune pathways could not be confirmed. The present data lays a theoretical foundation to further explore the mechanism of how CRP protects fish against bacterial infection.