Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 159
Filtrar
1.
Front Immunol ; 12: 613145, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33833752

RESUMO

Fish interferon (IFN) is a crucial cytokine for a host to resist external pathogens, conferring cells with antiviral capacity. Meanwhile, grass carp reovirus (GCRV) is a strong pathogen that causes high mortality in grass carp. Therefore, it is necessary to study the strategy used by GCRV to evade the cellular IFN response. In this study, we found that GCRV 35-kDa protein (VP35) inhibited the host IFN production by degrading mitochondrial antiviral signaling (MAVS) protein through the autophagy pathway. First, the overexpression of VP35 inhibited the IFN activation induced by polyinosinic-polycytidylic acid (poly I:C) and MAVS, and the expression of downstream IFN-stimulated genes (ISGs) was also decreased by using VP35 under the stimulation. Second, VP35 interacted with MAVS; the experiments of truncated mutants of MAVS demonstrated that the caspase recruitment domain (CARD) and proline-rich (PRO) domains of MAVS were not necessary for this binding. Then, MAVS was degraded by using VP35 in a dose-dependent manner, and 3-MA (the autophagy pathway inhibitor) significantly blocked the degradation, meaning that MAVS was degraded by using VP35 in the autophagy pathway. The result of MAVS degradation suggested that the antiviral capacity of MAVS was remarkably depressed when interrupted by VP35. Finally, in the host cells, VP35 reduced ifn transcription and made the cells vulnerable to virus infection. In conclusion, our results reveal that GCRV VP35 impairs the host IFN response by degrading MAVS through the autophagy pathway, supplying evidence of a fish virus immune evasion strategy.

2.
Dev Comp Immunol ; 121: 104103, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33857470

RESUMO

IL-35 plays a key role in regulatory T (Treg) and regulatory B (Breg) cell functions in mammals. CD25 has been demonstrated as one of the markers of Treg cells, and CD19+CD25hiCD71hi cells have been verified as a type of Breg cells in humans. These results indicate that there is a close relationship between IL-35 and CD25+ cells. In mammals, CD25 (alias IL-2Rα) has been identified as having high affinity and specificity for IL-2 binding, and is closely linked and structurally related to IL-15Rα, which having high affinity for IL-15 binding. In teleost, IL-15Rα can bind to both IL-2 and IL-15, with higher affinity to IL-15 than IL-2, and has been termed a CD25-like molecule in some research studies. To date, no studies of IL-35 and IL-15Rα have been documented in fish. In this work, five isoforms of IL-15Rα were cloned from grass carp, and a monoclonal antibody to the protein was developed. The results of flow cytometry and quantitative real-time PCR analyses demonstrated that grass carp IL-35 subunit genes EBI3a and IL-12p35 were mainly expressed in IL-15Rα+ cells, while the expression levels of IL-10 and TGF-ß in IL-15Rα+ and IL-15Rα- cells were insignificant. Recombinant grass carp IL-35 (rgcIL-35) could increase the proportion of IL-15Rα+ cells in leukocytes, and a certain proportion of IL-15Rα+ cells also appeared in myeloid cell subset II after stimulation with rgcIL-35. Meanwhile, the migration, phagocytic ability, and bactericidal ability of grass carp neutrophils were significantly decreased after stimulation with certain concentrations of rgcIL-35. Moreover, neutrophil apoptosis could be significantly inhibited by rgcIL-35.

3.
PLoS Pathog ; 17(2): e1009317, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33600488

RESUMO

The transmembrane protein 33 (TMEM33) was originally identified as an endoplasmic reticulum (ER) protein that influences the tubular structure of the ER and modulates intracellular calcium homeostasis. However, the role of TMEM33 in antiviral immunity in vertebrates has not been elucidated. In this article, we demonstrate that zebrafish TMEM33 is a negative regulator of virus-triggered interferon (IFN) induction via two mechanisms: mitochondrial antiviral signaling protein (MAVS) ubiquitination and a decrease in the kinase activity of TANK binding kinase 1 (TBK1). Upon stimulation with viral components, tmem33 was remarkably upregulated in the zebrafish liver cell line. The IFNφ1 promoter (IFNφ1pro) activity and mRNA level induced by retinoic acid-inducible gene (RIG)-I-like receptors (RLRs) were significantly inhibited by TMEM33. Knockdown of TMEM33 increased host ifn transcription. Subsequently, we found that TMEM33 was colocalized in the ER and interacted with the RLR cascades, whereas MAVS was degraded by TMEM33 during the K48-linked ubiquitination. On the other hand, TMEM33 reduced the phosphorylation of mediator of IFN regulatory factor 3 (IRF3) activation (MITA)/IRF3 by acting as a decoy substrate of TBK1, which was also phosphorylated. A functional domain assay revealed that the N-terminal transmembrane domain 1 (TM1) and TM2 regions of TMEM33 were necessary for IFN suppression. Finally, TMEM33 significantly attenuated the host cellular antiviral capacity by blocking the IFN response. Taken together, our findings provide insight into the different mechanisms employed by TMEM33 in cellular IFN-mediated antiviral process.

4.
Dev Comp Immunol ; 115: 103876, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32987012

RESUMO

In mammals, cyclic GMP-AMP synthase (cGAS) is a crucial cytosolic DNA sensor responsible for activating the interferon (IFN) response. A cGAS-like (cGASL) gene was previously identified from grass carp Ctenopharyngodon idellus, which is evolutionarily closest to cGAS but not a true ortholog of cGAS. Here, we found that grass carp cGASL targets mitochondrial antiviral signaling protein (MAVS) for autophagic degradation to negatively regulate fish IFN response. Firstly, the transcriptional level of cellular cgasl was upregulated by poly I:C stimulation, and overexpression of cGASL significantly decreased poly I:C- and MAVS-induced promoter activities and transcriptional levels of IFN and IFN-stimulated genes (ISGs). In addition, cGASL associated with MAVS and prompted autophagic degradation of MAVS in a dose-dependent manner. Finally, overexpression of cGASL attenuated MAVS-mediated cellular antiviral response. These results collectively indicate that cGASL negatively regulates fish IFN response by triggering autophagic degradation of MAVS.

5.
Fish Shellfish Immunol ; 108: 80-85, 2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33285164

RESUMO

The outer membrane protein U (OmpU) is a conserved outer membrane protein in a variety of pathogenic Vibrio species and has been considered as a vital protective antigen for vaccine development. Vibrio mimicus (V. mimicus) is the pathogen causing ascites disease in aquatic animals. In this study, the prokaryotically expressed and purified His-tagged OmpU of V. mimicus (His-OmpU) was used as a subunit vaccine. The formalin inactivated V. mimicus, purified His tag (His-tag), and PBS were used as controls. The vaccinated yellow catfish were challenged with V. mimicus at 28 days post-vaccination, and the results showed that the His-OmpU and inactivated V. mimicus groups exhibited much higher survival rates than the His-tag and PBS groups. To fully understand the underlying mechanism, we detected the expression levels of several immune-related genes in the spleen of fish at 28 days post-vaccination and 24 h post-challenge. The results showed that most of the detected immune-related genes were significantly upregulated in His-OmpU and inactivated V. mimicus groups. In addition, we performed the serum bactericidal activity assay, and the results showed that the serum from His-OmpU and inactivated V. mimicus groups exhibited much stronger bactericidal activity against V. mimicus than those of His-tag and PBS groups. Finally, the serum agglutination antibody was detected, and the antibody could be detected in His-OmpU and inactivated V. mimicus groups with the antibody titers increasing along with the time post-vaccination, but not in His-tag or PBS group. Our data reveal that the recombinant OmpU elicits potent protective immune response and is an effective vaccine candidate against V. mimicus in yellow catfish.

6.
J Genet Genomics ; 47(9): 547-561, 2020 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-33309050

RESUMO

Suppressive regulatory T cells (Treg cells) play a vital role in preventing autoimmunity and restraining excessive immune response to both self- and non-self-antigens. Studies on humans and mice show that the Forkhead box p3 (Foxp3) is a key regulatory gene for the development and function of Treg cells. In zebrafish, Treg cells have been identified by using foxp3a as a reliable marker. However, little is known about the function of foxp3a and Treg cells in gonadal development and sex differentiation. Here, we show that foxp3a is essential for maintaining immune homeostasis in zebrafish testis development. We found that foxp3a was specifically expressed in a subset of T cells in zebrafish testis, while knockout of foxp3a led to deficiency of foxp3a-positive Treg cells in the testis. More than 80% of foxp3a-/- mutants developed as subfertile males, and the rest of the mutants developed as fertile females with decreased ovulation. Further study revealed that foxp3a-/- mutants had a delayed juvenile ovary-to-testis transition in definite males and sex reversal in about half of the definite females, which led to a dominance of later male development. Owing to the absence of foxp3a-positive Treg cells in the differentiating testis of foxp3a-/- mutants, abundant T cells and macrophages expand to disrupt an immunosuppressive milieu, resulting in defective development of germ cells and gonadal somatic cells and leading to development of infertile males. Therefore, our study reveals that foxp3a-positive Treg cells play an essential role in the orchestration of gonadal development and sex differentiation in zebrafish.

7.
Front Immunol ; 11: 545302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33193312

RESUMO

Viruses typically target host RIG-I-like receptors (RLRs), a group of key factors involved in interferon (IFN) production, to enhance viral infection. To date, though immune evasion methods to contradict IFN production have been characterized for a series of terrestrial viruses, the strategies employed by fish viruses remain unclear. Here, we report that all grass carp reovirus (GCRV) proteins encoded by segments S1 to S11 suppress mitochondrial antiviral signaling protein (MAVS)-mediated IFN expression. First, the GCRV viral proteins blunted the MAVS-induced expression of IFN, and impair MAVS antiviral capacity significantly. Interestingly, subsequent co-immunoprecipitation experiments demonstrated that all GCRV viral proteins interacted with several RLR cascades, especially with TANK-binding kinase 1 (TBK1) which was the downstream factor of MAVS. To further illustrate the mechanisms of these interactions between GCRV viral proteins and host RLRs, two of the viral proteins, NS79 (S4) and VP3 (S3), were selected as representative proteins for two distinguished mechanisms. The obtained data demonstrated that NS79 was phosphorylated by gcTBK1, leading to the reduction of host substrate gcIRF3/7 phosphorylation. On the other hand, VP3 degraded gcMAVS and the degradation was significantly reversed by 3-MA. The biological effects of both NS79 and VP3 were consistently found to be related to the suppression of IFN expression and the promotion of viral evasion. Our findings shed light on the special evasion mechanism utilized by fish virus through IFN regulation, which might differ between fish and mammals.

8.
ACS Appl Mater Interfaces ; 12(43): 49101-49110, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33063985

RESUMO

In the mixed matrix membrane (MMM), the interface between the filler and the polymer matrix will directly affect the gas separation performance of the membranes. Reasonable interfacial design in MMMs is thus important and necessary. In this work, metal-organic coordination interaction is used to construct the interface in metal-organic framework (MOF) nanosheet-based polyimide MMMs where ultrathin Co-benzenedicarboxylate MOF nanosheets (CBMNs) with a thickness less than 5 nm and a lateral size more than 5 µm are synthesized as fillers and a carboxyl-functionalized polyimide (6FDA-durene-DABA) is used as a polymer matrix. Because of the high aspect ratio (>1000) of CBMNs, abundant metal-organic coordination bonds are formed between Co2+ in CBMNs and the -COOH group in 6FDA-durene-DABA. As a result, the 6FDA-durene-DABA/CBMN MMMs exhibit improved separation performance for the CO2/CH4 and H2/CH4 gas pairs with H2/CH4 and CO2/CH4 selectivities up to 42.0 ± 4.0 and 33.6 ± 3.0, respectively. The enhanced interfacial interaction leads to the comprehensive separation performance of CO2/CH4 and H2/CH4 gas pairs approaching or surpassing the 2008 Robeson upper bound. In addition, the CO2 plasticization pressure of the MMMs is significantly enhanced up to ∼20 bar, which is 2 times that of the pure 6FDA-durene-DABA membrane. When separating a mixed gas of CO2/CH4, the selectivity of CO2/CH4 remains stable at around 23 and the CO2 permeability keeps around 400 barrer during the long-term test.

9.
RNA Biol ; : 1-10, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32940118

RESUMO

Leader RNA, a kind of virus-derived small noncoding RNA, has been proposed to play an important role in regulating virus replication, but the underlying mechanism remains elusive. In this study, snakehead vesiculovirus (SHVV), a kind of fish rhabdovirus causing high mortality to the cultured snakehead fish in China, was used to unveil the molecular function of leader RNA. High-throughput small RNA sequencing of SHVV-infected cells showed that SHVV produced two groups of leader RNAs (named legroup1 and legroup2) during infection. Overexpression and knockout experiments reveal that legroup1, but not legroup2, affects SHVV replication. Mechanistically, legroup1-mediated regulation of SHVV replication was associated with its interaction with the viral nucleoprotein (N). Moreover, the nucleotides 6-10 of legroup1 were identified as the critical region for its interaction with the N protein, and the amino acids 1-45 of N protein were proved to confer its interaction with the legroup1. Taken together, we identified two groups of SHVV leader RNAs and revealed a role in virus replication for one of the two types of leader RNAs. This study will help understand the role of leader RNA in regulating the replication of negative-stranded RNA viruses.

10.
Int J Med Mushrooms ; 22(7): 705-717, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32865927

RESUMO

Ganoderma tsugae strain MCCCMAS0053 cultivation on short logs results in varied yield and quality under different growth conditions. Thus, growth conditions need optimization to increase yield and quality. An indoor experiment with three shade treatments (A1, two layers of black sun-shade net; A2, one layer of black sun-shade net plus plastic mulch; A3, one layer of black sun-shade net) and a field experiment in two forest types (pine or mixed pine-oak) were conducted. The results showed that shading and forest type significantly affected light intensities and the growth, size, biomass, and bioactive components of G. tsugae fruiting bodies. In the indoor experiment, the mean dry weight of the fruiting body and the diameter of the pileus in A2 increased by 21.51-44.98% and 13.42-22.26%, respectively, compared with those of A1 and A3. Similarly, the accumulation of the bioactive compounds (polysaccharides, total amino acids, and total essential amino acids) in the pileus and stipe were greater in A2 than in A1 and A3. Furthermore, compared with pure pine forest cultivation, fruiting bodies cultivated in mixed pine-oak forest had greater dry weight, pileus diameter, and more bioactive compounds. In addition, no significant difference was found between the A2 and mixed pine-oak treatments, which had a similar light intensity (from 1116 to 2367 lx). Hence, this suggests that the A2 shade treatment or cultivation in mixed pine-oak forest is beneficial for production of G. tsugae fruiting bodies, and light intensity may play a critical role in this process.

11.
J Immunol ; 205(7): 1819-1829, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32859727

RESUMO

IFN is essential for hosts to defend against viral invasion, whereas it must be tightly regulated to prevent hyperimmune responses. Fish mitochondrial antiviral signaling protein (MAVS) is a vital factor for IFN production, but until now, there have been few studies on the regulation mechanisms of fish MAVS enabling IFN to be properly controlled. In this study, we show that zebrafish RNA-binding motif protein 47 (RBM47) promotes MAVS degradation in a lysosome-dependent manner to suppress IFN production. First, the transcription of IFN activated by polyinosinic/polycytidylic acid (poly I:C), spring viremia of carp virus, or retinoic acid-inducible gene I (RIG-I)-like receptor pathway components were significantly suppressed by RBM47. Second, RBM47 interacted with MAVS and promoted lysosome-dependent degradation of MAVS, changing the cellular location of MAVS from the cytoplasm to the lysosome region. Finally, RBM47 inhibited downstream MITA and IRF3/7 activation, impairing the host antiviral response. Collectively, these data suggest that zebrafish RBM47 negatively regulates IFN production by promoting lysosome-dependent degradation of MAVS, providing insights into the role of RBM47 in the innate antiviral immune response in fish.

12.
Plant Dis ; 2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32720888

RESUMO

English/Persian walnut (Juglans regia L.) is grown as an economically valuable crop in temperate and subtropical regions. In August of 2018, serious fruit anthracnose, with brown to black circular or subcircular or irregular sunken lesions (Fig.1A), occurred on walnut trees ("Xiangling" and "lvling") in 33 ha., 23 ha. and 20 ha. orchards in Lincheng and Neiqiu county, in Xingtai, Hebei, China. Diseased fruits were observed on 41% (19,000 trees), 31% (13,300 trees) and 34% (11,400 trees) walnut trees. Diseased leaves, with circular or irregular brown to gray sunken lesions, were observed on 2% (19,000 trees), 2% (13,300 trees) and 1% (11,400 trees) walnut trees. From each orchard, 25 diseased fruits and leaves were collected, respectively. Twenty-one single spore isolates were obtained from fruits of three orchards and none from leaves as described by Cai et al. (2009). Six representative isolates 1811-1, 1811-4, 1811-7, 1811-8, 1811-11 and 1811-18, two from each orchard, were selected for further study. Colonies on PDA grew 11.8 mm d-1 at 25℃ under a 12/12 h light/dark cycle for 7 d. The upper side of colonies was milky (Fig.1 B), and reverse side was dark brown to brownish yellow. A few acervuli were observed on colonies. Conidiogenous cells were cylindrical to clavate, 10.6-29.7 × 3.1-5.3 µm (mean=21.3 × 4.0 µm, n=30) (Fig.1F). Setae were not observed. Conidia were smooth-walled, aseptate, straight or slightly distorted, cylindrical with one end slightly acute or broadly rounded ends, and 16.6-21.6 × 6.0-7.5 µm (mean=19.2 × 6.7 µm, n=30) (Fig.1 C). Appressoria were mostly irregular in outline, deeply lobed or lightly lobed, gray brown to dark brown, 8.3-16.6 × 7.1-14.5 µm (mean=12.5 × 9.7 µm, n=30) (Fig.1 D-E). Microscopic features were similar to the description of C. aenigma (Weir et al. 2012). To further identify isolates, the ribosomal internal transcribed spacers (ITS), ß-tubulin 2 (TUB2), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS) and chitin synthase (CHS-1) loci of representative isolates were amplified using ITS4/ITS5, Bt2a/Bt2b, CL1/CL2, GDF1/GDR1, GSF1/GSR1 and CHS-79F/CHS-345R primers (Prihastuti et al. 2009; Carbone & Kohn 1999). Sequences of representative isolate 1811-1 were submitted to GenBank (ITS: MN893316, TUB: MN893317, CAL: MN893312, GAPDH: MN893314, GS: MN893315, CHS-1: MN893313). Maximum likehood analysis of sequences of representative isolates and reference sequences of Colletotrichum spp. from GenBank revealed that six isolates clustered together with C. aenigma ex-type culture ICMP18608, and the bootstrap value was 100% (Fig.2). Pathogenicity tests were conducted on walnut fruit as described by Wang et al. (2017, 2018) and Cai et al. (2009). 10 wounded and 10 nonwounded fruits ("Xiangling", 35 mm diameter) were inoculated with isolates 1811-1, 1811-7 and 1811-11 conidial suspension (106 spore/mL) obtained from 10 d colonies grown on PDA at 25℃, respectively. 10 wounded and 10 nonwounded fruits were inoculated with sterile water. Inoculated and control fruits were incubated in containers at 25℃ in a 12/12 h light/dark cycle. After 10 days, necrotic lesions were observed in all inoculated fruits. The pathogen C. aenigma was reisolated from all inoculated fruits but not from control fruits. To our knowledge, this is the first report of C. aenigma causing walnut anthracnose in China. It is urgent to control walnut anthracnose caused by different species of Colletotrichum.

13.
Biomolecules ; 10(6)2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32481513

RESUMO

Hepcidin is an antimicrobial peptide and regulator of iron homeostasis which has two isoforms in most fishes and some mammals. Previous studies have reported that the two hepcidin isoforms have different roles. Hamp type-1 plays a regulatory role in iron metabolism and hamp type-2 mostly performs an antimicrobial role. In this study, we found that Ctenopharyngodon idella (C. idella) have only one hepcidin isoform (hamp type-1), which showed both broad-spectrum antibacterial and iron regulatory functions. C. idella hepcidin mature peptide (hepcidin-25) and truncated peptide (hepcidin-20) exhibited bactericidal activities against both Gram-positive and Gram-negative bacteria in a dose-dependent manner in part through membrane rupture and binding to bacterial genomic DNA. The data from challenge tests demonstrated that the administration of hepcidin-25 significantly reduced mortality rates of C. idella by A. hydrophila infection, probably due to direct bactericidal activities of the peptide and a reduction of iron content in the fish serum. In addition, a comparison between hepcidin-20 and -25 suggests that the N terminal 5 amino acids play a critical role in reducing iron content in fish serum. Our findings revealed an important role of hamp type-1 in maintaining iron homeostasis and fighting against bacterial infections, suggesting the hepcidin has implications for the prevention and control of bacterial infection in aquaculture.

14.
J Virol ; 94(15)2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32434890

RESUMO

Spring viremia of carp virus (SVCV) is a highly pathogenic Vesiculovirus in the common carp. The phosphoprotein (P protein) of SVCV is a multifunctional protein that acts as a polymerase cofactor and an antagonist of cellular interferon (IFN) response. Here, we report the 1.5-Å-resolution crystal structure of the P protein central domain (PCD) of SVCV (SVCVPCD). The PCD monomer consists of two ß sheets, an α helix, and another two ß sheets. Two PCD monomers pack together through their hydrophobic surfaces to form a dimer. The mutations of residues on the hydrophobic surfaces of PCD disrupt the dimer formation to different degrees and affect the expression of host IFN consistently. Therefore, the oligomeric state formation of the P protein of SVCV is an important mechanism to negatively regulate host IFN response.IMPORTANCE SVCV can cause spring viremia of carp with up to 90% lethality, and it is the homologous virus of the notorious vesicular stomatitis virus (VSV). There are currently no drugs that effectively cure this disease. P proteins of negative-strand RNA viruses (NSVs) play an essential role in many steps during the replication cycle and an additional role in immunosuppression as a cofactor. All P proteins of NSVs are oligomeric, but the studies on the role of this oligomerization mainly focus on the process of virus transcription or replication, and there are few studies on the role of PCD in immunosuppression. Here, we present the crystal structure of SVCVPCD A new mechanism of immune evasion is clarified by exploring the relationship between SVCVPCD and host IFN response from a structural biology point of view. These findings may provide more accurate target sites for drug design against SVCV and provide new insights into the function of NSVPCD.


Assuntos
Fosfoproteínas/química , Rhabdoviridae/química , Proteínas Virais/química , Animais , Cristalografia por Raios X , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta
15.
Fish Shellfish Immunol ; 102: 449-459, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32408017

RESUMO

Calcium (Ca) is a messenger that regulates a multitude of physiological processes, but its functions in antiviral progress remain undefined. In this study, we found that Ca2+ enhances fish survival to defend against spring viraemia of carp virus (SVCV) infection by reversing the instability of p53 mediated by the viral protein. First, Ca2+ significantly protected cells and fish against SVCV infection by inducing early apoptosis. Additionally, p53 expression, which was inhibited by SVCV N protein, was upregulated by Ca2+ treatment. Then, the mechanism underlying the reduction of K63-linked p53 ubiquitination by SVCV N protein via the K358 site was completely prevented by Ca2+. These findings reveal the role of Ca2+ in lower vertebrates in the antiviral response, which is connected to and corresponds with viral immune evasion, providing a solution to fish diseases caused by pathogens.

16.
Dev Comp Immunol ; 110: 103728, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32387557

RESUMO

In mammals, interleukin 21 (IL-21) is a type I four-helical bundle cytokine produced by activated T cells that has pleiotropic functions on immune cells. Although IL-21 has been discovered in fish, the splicing variants of this cytokine and their functions on B cells are unclear. In this study, based on the original transcript of grass carp IL-21 (named gcIL-21sv1 in this study), two alternative splicing variants, named gcIL-21sv2 and gcIL-21sv3, were cloned and characterized. The protein sequences of gcIL-21sv1 and gcIL-21sv2 consist of four α-helixes, and only the six amino acid residues at the C-terminal are different. Unlike gcIL-21sv1 and gcIL-21sv2, gcIL-21sv3 lacks the C-terminal region. The expression analysis showed that gcIL-21sv1, gcIL-21sv2, and gcIL-21sv3 were constitutively expressed in all the tested tissues, and their expression could be significantly up-regulated by LPS and Poly (I:C) in head kidney leukocytes (HKLs), with the fold change of gcIL-21sv1 being higher than that of gcIL-21sv2 and gcIL-21sv3. Recombinant gcIL-21sv1 and gcIL-21sv2, but not gcIL-21sv3, could induce the proliferation of IgM+ B cells and the secretion of IgM, with the activity of gcIL-21sv1 being stronger than that of gcIL-21sv2, indicating that the C-terminal region plays important roles in the function of gcIL-21. Taken together, this study found that, like IL-21 in human and mouse, IL-21 splicing variants also exist in fish, and the regulatory activities of these variants in humoral immunity are differ, suggesting that grass carp may balance the immune response mediated by IL-21 through alternative splicing.

17.
Microorganisms ; 8(4)2020 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-32260465

RESUMO

Edwardsiella piscicida, a facultative aerobic pathogen belonging to the Enterobacteriaceae family, is the etiological agent of edwardsiellosis that causes significant economic loses in the aquaculture industry. cAMP receptor protein (CRP) is one of the most important transcriptional regulators, which can regulate large quantities of operons in different bacteria. Here we characterize the crp gene and report the effect of a crp deletion in E. piscicida. The crp-deficient mutant lost the capacity to utilize maltose, and showed significantly reduced motility due to the lack of flagella synthesis. We further constructed a ΔPcrp mutant to support that the phenotype above was caused by the crp deletion. Evidence obtained in fish serum killing assay and competitive infection assay strongly indicated that the inactivation of crp impaired the ability of E. piscicida to evade host immune clearance. More importantly, the virulence of the crp mutant was attenuated in both zebrafish and channel catfish, with reductions in mortality rates. In the end, we found that crp mutant could confer immune protection against E. piscicida infection to zebrafish and channel catfish, indicating its potential as a live attenuated vaccine.

18.
Fish Shellfish Immunol ; 99: 99-106, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32032764

RESUMO

Grass carp reovirus (GCRV) is an efficient pathogen causing high mortality in grass carp, meanwhile, fish interferon (IFN) is a powerful cytokine enabling host cells to establish an antiviral state; therefore, the strategies used by GCRV to escape the cellular IFN response need to be investigated. Here, we report that GCRV VP56 inhibits host IFN production by degrading the transcription factor IFN regulatory factor 7 (IRF7). First, overexpression of VP56 inhibited the IFN production induced by the polyinosinic-polycytidylic acid (poly I:C) and mitochondrial antiviral signaling protein (MAVS), while the capacity of IRF7 on IFN induction was unaffected. Second, VP56 interacted with RLRs but did not affect the stabilization of the proteins in the normal state, while the phosphorylated IRF7 activated by TBK1 was degraded by VP56 through K48-linked ubiquitination. Finally, overexpression of VP56 remarkably reduced the host cellular ifn transcription and facilitated viral proliferation. Taken together, our results demonstrate that GCRV VP56 suppresses the host IFN response by targeting phosphorylated IRF7 for ubiquitination and degradation.


Assuntos
Carpas/virologia , Fator Regulador 7 de Interferon/metabolismo , Interferons/antagonistas & inibidores , Infecções por Reoviridae/veterinária , Proteínas Virais/genética , Animais , Carpas/imunologia , Feminino , Células HEK293 , Humanos , Imunidade Inata , Fator Regulador 7 de Interferon/imunologia , Interferons/imunologia , Ovário/citologia , Fosforilação , Poli I-C/farmacologia , Reoviridae , Infecções por Reoviridae/imunologia , Ubiquitinação , Proteínas Virais/imunologia
19.
Sci Rep ; 10(1): 3435, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103052

RESUMO

The popular medicinal mushroom Ganoderma lucidum (Fr.) Karst. [Ling Zhi] has been widely used for the general promotion of health and longevity in Asian countries. Continuous cultivation may affect soil microbe and soil properties. However, the effect of G. lucidum cultivation on related wood segments, soil and tree roots microbial communities and soil properties is remain unknown. In our study, the microbial communities of soils, wood segments, and tree roots before and after G. lucidum cultivation were investigated by Illumina Miseq sequencing of both ITS and 16S rDNA, and taxonomic composition of eukaryotic and prokaryotic microorganisms were observed. Indices of microbial richness, diversity and evenness significantly differed between before and after G. lucidum cultivation. Each of the investigated sampling type harbored a distinctive microbial community and differed remarkably before and after G. lucidum cultivation. Ascomycota and Basidiomycota (fungi), Proteobacteria and Actinobacteria (bacteria) showed significant differences after Ling Zhi cultivation. The soil property values also changed after cultivation. The redundancy analysis (RDA) showed that both the fungal and bacterial community structure significantly correlated with soil humus, pH, nitrogen, carbon and trace elements (Fe, Zn, Mn, Cu) contents. The results indicated that G. lucidum cultivation may have significant differed the associated microbial community structures and soil properties. The study will provide useful information for G. lucidum cultivation and under-forest economic development.


Assuntos
Reishi/crescimento & desenvolvimento , Microbiologia do Solo , Solo/química , Madeira/microbiologia , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Basidiomycota/genética , Basidiomycota/isolamento & purificação , Microbiota , Raízes de Plantas/microbiologia , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Análise de Sequência de DNA
20.
Cancer Immunol Immunother ; 69(5): 779-788, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32052078

RESUMO

Dendritic cells are crucial for the initiation and regulation of immune responses against cancer and pathogens. DCs are heterogeneous and highly specialized antigen-presenting cells. Human DCs comprise several subsets with different phenotypes and functional properties. In the steady state, human DC subsets have been well studied. However, the components of DC subsets and their immune functions during the inflamed setting are poorly understood. We identified and characterized DC subsets in the malignant pleural effusions of NSCLC patients. We analyzed the capacity of these DC subsets to induce T-cell differentiation. We observed the presence of inflammatory DCs (infDCs) and macrophages in the malignant pleural effusions of NSCLC patients, as identified by the CD11C+HLA-DR+CD16-BDCA1+ and CD11C+HLA-DR+CD16+BDCA1- phenotypes, respectively. InfDCs represented approximately 1% of the total light-density cells in the pleural effusion and were characterized by the expression of CD206, CD14, CD11b, and CD1α, which were absent on blood DCs. InfDCs also expressed CD80, although at a low level. As infDCs did not express CD40, CD83 and CD275, they remained functionally immature. We found that TLR agonists promoted the maturation of infDCs. Compared with macrophages, infDCs had a weaker capacity to phagocytose necrotic tumor cell lysates. However, only infDCs induced autologous memory CD4+ T-cell differentiation into Th1 cells. For the first time, we found that infDCs were present in the malignant pleural effusions of NSCLC patients. We conclude that infDCs represent a distinct human DC subset and induce Th1 cell differentiation in the presence of TLR agonists.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Células Dendríticas/imunologia , Neoplasias Pulmonares/patologia , Derrame Pleural Maligno/imunologia , Células Th1/imunologia , Carcinoma Pulmonar de Células não Pequenas/secundário , Comunicação Celular/efeitos dos fármacos , Comunicação Celular/imunologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Células Dendríticas/metabolismo , Humanos , Imidazóis/farmacologia , Lipopolissacarídeos/farmacologia , Neoplasias Pulmonares/imunologia , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Fagocitose/efeitos dos fármacos , Fagocitose/imunologia , Cultura Primária de Células , Receptores Toll-Like/agonistas , Receptores Toll-Like/metabolismo , Células Tumorais Cultivadas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...