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Structural characteristics and antiviral activity of multiple peptides derived from MDV glycoproteins B and H.

Wang X, Chi X, Wang M - Virol. J. (2011)

Bottom Line: These peptides were also significantly able to reduce lesion formation on chorioallantoic membranes (CAMs) of infected chicken embryos at a concentration of 0.5 mM in 60 μl of solution.None of the peptides exhibited cytotoxic effects at the concentrations tested.The present study examining the antiviral activity of these MDV peptides, which are useful as small-molecule antiviral inhibitors, provides information about the MDV entry mechanism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No, 2, Yuan Ming Yuan West Road, Haidian District, Beijing 100193, PR China. wangxj@cau.edu.cn

ABSTRACT

Background: Marek's disease virus (MDV), which is widely considered to be a natural model of virus-induced lymphoma, has the potential to cause tremendous losses in the poultry industry. To investigate the structural basis of MDV membrane fusion and to identify new viral targets for inhibition, we examined the domains of the MDV glycoproteins gH and gB.

Results: Four peptides derived from the MDV glycoprotein gH (gHH1, gHH2, gHH3, and gHH5) and one peptide derived from gB (gBH1) could efficiently inhibit plaque formation in primary chicken embryo fibroblast cells (CEFs) with 50% inhibitory concentrations (IC50) of below 12 μM. These peptides were also significantly able to reduce lesion formation on chorioallantoic membranes (CAMs) of infected chicken embryos at a concentration of 0.5 mM in 60 μl of solution. The HR2 peptide from Newcastle disease virus (NDVHR2) exerted effects on MDV specifically at the stage of virus entry (i.e., in a cell pre-treatment assay and an embryo co-treatment assay), suggesting cross-inhibitory effects of NDV HR2 on MDV infection. None of the peptides exhibited cytotoxic effects at the concentrations tested. Structural characteristics of the five peptides were examined further.

Conclusions: The five MDV-derived peptides demonstrated potent antiviral activity, not only in plaque formation assays in vitro, but also in lesion formation assays in vivo. The present study examining the antiviral activity of these MDV peptides, which are useful as small-molecule antiviral inhibitors, provides information about the MDV entry mechanism.

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Prediction of functional domains of MDV gH and gB. (a) Linear representation of the MDV gH glycoprotein including potential HR regions and transmembrane region (TM). (b) Linear representation of the MDV gB glycoprotein including potential HR regions and TM region. gBH2 domain contains cleavage site located at aa residues 431 to 434. (c) Six HR domains of MDV gH as predicted by the ExPASy-Coils program. (d) Five HR domains of MDV gB as predicted by the ExPASy-Coils program.
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Figure 1: Prediction of functional domains of MDV gH and gB. (a) Linear representation of the MDV gH glycoprotein including potential HR regions and transmembrane region (TM). (b) Linear representation of the MDV gB glycoprotein including potential HR regions and TM region. gBH2 domain contains cleavage site located at aa residues 431 to 434. (c) Six HR domains of MDV gH as predicted by the ExPASy-Coils program. (d) Five HR domains of MDV gB as predicted by the ExPASy-Coils program.

Mentions: In this study, we searched for HR regions in MDV gH and gB proteins using a series of biological software packages. Six potential HR regions in gH and five potential HR regions in gB were identified (see Figure 1). To determine whether these peptides could affect virus infectivity, primary CEFs were incubated with peptides at increasing concentrations in the presence of 100 pfu MDV (i.e., the co-treatment assay). The cells were then incubated for 5 days at 37°C in DMEM supplemented with 2% FCS, and plaques were counted. Plaque formation is shown in Figure 2a. We also used an immunofluorescence (IFA) assay with anti-pp24 antibody to verify plaque formation [22] (see Figure 2b). Uninfected cells resembled cells in which plaque formation was inhibited, and they are not shown here. These experiments demonstrate that peptides gHH4, gHH6, and gBH2-5 could inhibit plaque formation at an IC50 of more than 25 μM. Five peptides (gHH1, gHH2, gHH3, gHH5, and gBH1) with IC50 values below 12 μM were selected for further studies. The IC50 values of gHH1, gHH2, gHH3, gHH5, and gBH1 were approximately 4, 8, 12, 8 and 9 μM, respectively. These results are shown in Figure 2c. In addition, gHH6 was considered for further analysis in current study because its hydrophilic character is similar to the most potent inhibitor gHH1, and they were two HR domains with the highest predicted tendency to form coiled-coil structures (see Figure 1c).


Structural characteristics and antiviral activity of multiple peptides derived from MDV glycoproteins B and H.

Wang X, Chi X, Wang M - Virol. J. (2011)

Prediction of functional domains of MDV gH and gB. (a) Linear representation of the MDV gH glycoprotein including potential HR regions and transmembrane region (TM). (b) Linear representation of the MDV gB glycoprotein including potential HR regions and TM region. gBH2 domain contains cleavage site located at aa residues 431 to 434. (c) Six HR domains of MDV gH as predicted by the ExPASy-Coils program. (d) Five HR domains of MDV gB as predicted by the ExPASy-Coils program.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3113977&req=5

Figure 1: Prediction of functional domains of MDV gH and gB. (a) Linear representation of the MDV gH glycoprotein including potential HR regions and transmembrane region (TM). (b) Linear representation of the MDV gB glycoprotein including potential HR regions and TM region. gBH2 domain contains cleavage site located at aa residues 431 to 434. (c) Six HR domains of MDV gH as predicted by the ExPASy-Coils program. (d) Five HR domains of MDV gB as predicted by the ExPASy-Coils program.
Mentions: In this study, we searched for HR regions in MDV gH and gB proteins using a series of biological software packages. Six potential HR regions in gH and five potential HR regions in gB were identified (see Figure 1). To determine whether these peptides could affect virus infectivity, primary CEFs were incubated with peptides at increasing concentrations in the presence of 100 pfu MDV (i.e., the co-treatment assay). The cells were then incubated for 5 days at 37°C in DMEM supplemented with 2% FCS, and plaques were counted. Plaque formation is shown in Figure 2a. We also used an immunofluorescence (IFA) assay with anti-pp24 antibody to verify plaque formation [22] (see Figure 2b). Uninfected cells resembled cells in which plaque formation was inhibited, and they are not shown here. These experiments demonstrate that peptides gHH4, gHH6, and gBH2-5 could inhibit plaque formation at an IC50 of more than 25 μM. Five peptides (gHH1, gHH2, gHH3, gHH5, and gBH1) with IC50 values below 12 μM were selected for further studies. The IC50 values of gHH1, gHH2, gHH3, gHH5, and gBH1 were approximately 4, 8, 12, 8 and 9 μM, respectively. These results are shown in Figure 2c. In addition, gHH6 was considered for further analysis in current study because its hydrophilic character is similar to the most potent inhibitor gHH1, and they were two HR domains with the highest predicted tendency to form coiled-coil structures (see Figure 1c).

Bottom Line: These peptides were also significantly able to reduce lesion formation on chorioallantoic membranes (CAMs) of infected chicken embryos at a concentration of 0.5 mM in 60 μl of solution.None of the peptides exhibited cytotoxic effects at the concentrations tested.The present study examining the antiviral activity of these MDV peptides, which are useful as small-molecule antiviral inhibitors, provides information about the MDV entry mechanism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No, 2, Yuan Ming Yuan West Road, Haidian District, Beijing 100193, PR China. wangxj@cau.edu.cn

ABSTRACT

Background: Marek's disease virus (MDV), which is widely considered to be a natural model of virus-induced lymphoma, has the potential to cause tremendous losses in the poultry industry. To investigate the structural basis of MDV membrane fusion and to identify new viral targets for inhibition, we examined the domains of the MDV glycoproteins gH and gB.

Results: Four peptides derived from the MDV glycoprotein gH (gHH1, gHH2, gHH3, and gHH5) and one peptide derived from gB (gBH1) could efficiently inhibit plaque formation in primary chicken embryo fibroblast cells (CEFs) with 50% inhibitory concentrations (IC50) of below 12 μM. These peptides were also significantly able to reduce lesion formation on chorioallantoic membranes (CAMs) of infected chicken embryos at a concentration of 0.5 mM in 60 μl of solution. The HR2 peptide from Newcastle disease virus (NDVHR2) exerted effects on MDV specifically at the stage of virus entry (i.e., in a cell pre-treatment assay and an embryo co-treatment assay), suggesting cross-inhibitory effects of NDV HR2 on MDV infection. None of the peptides exhibited cytotoxic effects at the concentrations tested. Structural characteristics of the five peptides were examined further.

Conclusions: The five MDV-derived peptides demonstrated potent antiviral activity, not only in plaque formation assays in vitro, but also in lesion formation assays in vivo. The present study examining the antiviral activity of these MDV peptides, which are useful as small-molecule antiviral inhibitors, provides information about the MDV entry mechanism.

Show MeSH
Related in: MedlinePlus