Limits...
Antiviral activity and increased host defense against influenza infection elicited by the human cathelicidin LL-37.

Barlow PG, Svoboda P, Mackellar A, Nash AA, York IA, Pohl J, Davidson DJ, Donis RO - PLoS ONE (2011)

Bottom Line: Cationic Host Defense Peptides (CHDP, also known as antimicrobial peptides), which include cathelicidins and defensins, are key components of the innate immune system that are upregulated during infection and inflammation.The human cathelicidin, LL-37, and the murine cathelicidin, mCRAMP, demonstrated significant anti-viral activity in vivo, reducing disease severity and viral replication in infected mice to a similar extent as the well-characterized influenza virus-specific antiviral drug zanamivir.These data suggest that treatment of influenza-infected individuals with cathelicidin-derived therapeutics, or modulation of endogenous cathelicidin production may provide significant protection against disease.

View Article: PubMed Central - PubMed

Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.

ABSTRACT
The extensive world-wide morbidity and mortality caused by influenza A viruses highlights the need for new insights into the host immune response and novel treatment approaches. Cationic Host Defense Peptides (CHDP, also known as antimicrobial peptides), which include cathelicidins and defensins, are key components of the innate immune system that are upregulated during infection and inflammation. Cathelicidins have immunomodulatory and anti-viral effects, but their impact on influenza virus infection has not been previously assessed. We therefore evaluated the effect of cathelicidin peptides on disease caused by influenza A virus in mice. The human cathelicidin, LL-37, and the murine cathelicidin, mCRAMP, demonstrated significant anti-viral activity in vivo, reducing disease severity and viral replication in infected mice to a similar extent as the well-characterized influenza virus-specific antiviral drug zanamivir. In vitro and in vivo experiments suggested that the peptides may act directly on the influenza virion rather than via receptor-based mechanisms. Influenza virus-infected mice treated with LL-37 had lower concentrations of pro-inflammatory cytokines in the lung than did infected animals that had not been treated with cathelicidin peptides. These data suggest that treatment of influenza-infected individuals with cathelicidin-derived therapeutics, or modulation of endogenous cathelicidin production may provide significant protection against disease.

Show MeSH

Related in: MedlinePlus

D-Isomer cathelicidins inhibit influenza virus.(A,B) Groups of 5 mice were infected with 10 MLD50 of A/PR/8/34 influenza virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 7. Mouse weight and survival was monitored daily up to 14 days post infection. Data represent mean values ± SEM from n = 1 experiment. Statistical analysis was performed using Kaplan Meier with a Mantel-Cox (log rank) test. Survival curves obtained with Zanamivir, D-LL-37 and D-mCRAMP treatments were significantly different (P≤0.001) compared to saline control treatment. (C) Groups of 5 mice were infected with 10MLD50 of A/PR/8/34 virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 2. Mice were euthanized on day 3 and viral titer in the lungs was assessed by plaque assay. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare virus infected animals with virus/peptide and virus/zanamivir treated animals (*P≤0.05). (D) The antiviral activity of the cathelicidins D-LL-37 and D-mCRAMP was assessed. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare PR/8 only titer with PR/8 + Peptide (*P≤0.05, ** P≤0.01).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3198734&req=5

pone-0025333-g005: D-Isomer cathelicidins inhibit influenza virus.(A,B) Groups of 5 mice were infected with 10 MLD50 of A/PR/8/34 influenza virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 7. Mouse weight and survival was monitored daily up to 14 days post infection. Data represent mean values ± SEM from n = 1 experiment. Statistical analysis was performed using Kaplan Meier with a Mantel-Cox (log rank) test. Survival curves obtained with Zanamivir, D-LL-37 and D-mCRAMP treatments were significantly different (P≤0.001) compared to saline control treatment. (C) Groups of 5 mice were infected with 10MLD50 of A/PR/8/34 virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 2. Mice were euthanized on day 3 and viral titer in the lungs was assessed by plaque assay. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare virus infected animals with virus/peptide and virus/zanamivir treated animals (*P≤0.05). (D) The antiviral activity of the cathelicidins D-LL-37 and D-mCRAMP was assessed. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare PR/8 only titer with PR/8 + Peptide (*P≤0.05, ** P≤0.01).

Mentions: To further test whether the anti-influenza activity observed with LL-37 and mCRAMP peptides was related to the physical properties of the peptide or whether interactions with a specific receptor might be involved, we synthesized LL-37 and mCRAMP peptides using only D-amino acids instead of L-amino acids and tested the antiviral properties of the peptides both in vitro and in vivo. Notably, both LL-37 and mCRAMP that had been synthesized with D-amino acids demonstrated effective antiviral activity in vitro, reducing titers as effectively as the L-peptides (Figure 5D). Consistent with this in vitro effect, the D-peptides were also effective in vivo. Mice were treated with nebulized D-LL-37 and D-mCRAMP for 1 day prior to and for 7 days post infection with 10MLD50 A/PR/8/34 (H1N1) virus. Mice were monitored for 14 days following infection. Mice that had received treatment with either of the D-analogs showed less body weight loss compared to control infected animals (Figure 5A) and survival was dramatically enhanced (Figure 5B). All control infected mice succumbed to PR/8 infection by day 8. However, there was significantly greater survival in the mice treated with D-LL-37 (80%) or D-mCRAMP (100%) (Figures 5A and 5B, P≤0.001). Additionally, lung virus titers assessed at 3dpi were markedly lower in mice treated with D-peptides compared with mice that had been treated with nebulized saline only (P≤0.05; Figure 5C). Weight loss, survival and lung titers in D-peptide treated mice were comparable to those in mice treated with zanamivir. These data suggest that the antiviral effects mediated by cathelicidins in vivo may be due to physical properties of the peptides rather than interactions with stereoisomer-specific receptors.


Antiviral activity and increased host defense against influenza infection elicited by the human cathelicidin LL-37.

Barlow PG, Svoboda P, Mackellar A, Nash AA, York IA, Pohl J, Davidson DJ, Donis RO - PLoS ONE (2011)

D-Isomer cathelicidins inhibit influenza virus.(A,B) Groups of 5 mice were infected with 10 MLD50 of A/PR/8/34 influenza virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 7. Mouse weight and survival was monitored daily up to 14 days post infection. Data represent mean values ± SEM from n = 1 experiment. Statistical analysis was performed using Kaplan Meier with a Mantel-Cox (log rank) test. Survival curves obtained with Zanamivir, D-LL-37 and D-mCRAMP treatments were significantly different (P≤0.001) compared to saline control treatment. (C) Groups of 5 mice were infected with 10MLD50 of A/PR/8/34 virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 2. Mice were euthanized on day 3 and viral titer in the lungs was assessed by plaque assay. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare virus infected animals with virus/peptide and virus/zanamivir treated animals (*P≤0.05). (D) The antiviral activity of the cathelicidins D-LL-37 and D-mCRAMP was assessed. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare PR/8 only titer with PR/8 + Peptide (*P≤0.05, ** P≤0.01).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198734&req=5

pone-0025333-g005: D-Isomer cathelicidins inhibit influenza virus.(A,B) Groups of 5 mice were infected with 10 MLD50 of A/PR/8/34 influenza virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 7. Mouse weight and survival was monitored daily up to 14 days post infection. Data represent mean values ± SEM from n = 1 experiment. Statistical analysis was performed using Kaplan Meier with a Mantel-Cox (log rank) test. Survival curves obtained with Zanamivir, D-LL-37 and D-mCRAMP treatments were significantly different (P≤0.001) compared to saline control treatment. (C) Groups of 5 mice were infected with 10MLD50 of A/PR/8/34 virus via intranasal administration on day 0. Mice were nebulized with 200 µl of saline (control), zanamivir (500 µg/ml), D-LL-37 peptide (500 µg/ml) or D-mCRAMP peptide (500 µg/ml) once daily from day -1 to day 2. Mice were euthanized on day 3 and viral titer in the lungs was assessed by plaque assay. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare virus infected animals with virus/peptide and virus/zanamivir treated animals (*P≤0.05). (D) The antiviral activity of the cathelicidins D-LL-37 and D-mCRAMP was assessed. Figure is representative of n = 3 independent experiments. Figure shows mean values ± SEM. Statistical analysis was performed using an unpaired t-test to compare PR/8 only titer with PR/8 + Peptide (*P≤0.05, ** P≤0.01).
Mentions: To further test whether the anti-influenza activity observed with LL-37 and mCRAMP peptides was related to the physical properties of the peptide or whether interactions with a specific receptor might be involved, we synthesized LL-37 and mCRAMP peptides using only D-amino acids instead of L-amino acids and tested the antiviral properties of the peptides both in vitro and in vivo. Notably, both LL-37 and mCRAMP that had been synthesized with D-amino acids demonstrated effective antiviral activity in vitro, reducing titers as effectively as the L-peptides (Figure 5D). Consistent with this in vitro effect, the D-peptides were also effective in vivo. Mice were treated with nebulized D-LL-37 and D-mCRAMP for 1 day prior to and for 7 days post infection with 10MLD50 A/PR/8/34 (H1N1) virus. Mice were monitored for 14 days following infection. Mice that had received treatment with either of the D-analogs showed less body weight loss compared to control infected animals (Figure 5A) and survival was dramatically enhanced (Figure 5B). All control infected mice succumbed to PR/8 infection by day 8. However, there was significantly greater survival in the mice treated with D-LL-37 (80%) or D-mCRAMP (100%) (Figures 5A and 5B, P≤0.001). Additionally, lung virus titers assessed at 3dpi were markedly lower in mice treated with D-peptides compared with mice that had been treated with nebulized saline only (P≤0.05; Figure 5C). Weight loss, survival and lung titers in D-peptide treated mice were comparable to those in mice treated with zanamivir. These data suggest that the antiviral effects mediated by cathelicidins in vivo may be due to physical properties of the peptides rather than interactions with stereoisomer-specific receptors.

Bottom Line: Cationic Host Defense Peptides (CHDP, also known as antimicrobial peptides), which include cathelicidins and defensins, are key components of the innate immune system that are upregulated during infection and inflammation.The human cathelicidin, LL-37, and the murine cathelicidin, mCRAMP, demonstrated significant anti-viral activity in vivo, reducing disease severity and viral replication in infected mice to a similar extent as the well-characterized influenza virus-specific antiviral drug zanamivir.These data suggest that treatment of influenza-infected individuals with cathelicidin-derived therapeutics, or modulation of endogenous cathelicidin production may provide significant protection against disease.

View Article: PubMed Central - PubMed

Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.

ABSTRACT
The extensive world-wide morbidity and mortality caused by influenza A viruses highlights the need for new insights into the host immune response and novel treatment approaches. Cationic Host Defense Peptides (CHDP, also known as antimicrobial peptides), which include cathelicidins and defensins, are key components of the innate immune system that are upregulated during infection and inflammation. Cathelicidins have immunomodulatory and anti-viral effects, but their impact on influenza virus infection has not been previously assessed. We therefore evaluated the effect of cathelicidin peptides on disease caused by influenza A virus in mice. The human cathelicidin, LL-37, and the murine cathelicidin, mCRAMP, demonstrated significant anti-viral activity in vivo, reducing disease severity and viral replication in infected mice to a similar extent as the well-characterized influenza virus-specific antiviral drug zanamivir. In vitro and in vivo experiments suggested that the peptides may act directly on the influenza virion rather than via receptor-based mechanisms. Influenza virus-infected mice treated with LL-37 had lower concentrations of pro-inflammatory cytokines in the lung than did infected animals that had not been treated with cathelicidin peptides. These data suggest that treatment of influenza-infected individuals with cathelicidin-derived therapeutics, or modulation of endogenous cathelicidin production may provide significant protection against disease.

Show MeSH
Related in: MedlinePlus