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The Rac1 inhibitor NSC23766 exerts anti-influenza virus properties by affecting the viral polymerase complex activity.

Dierkes R, Warnking K, Liedmann S, Seyer R, Ludwig S, Ehrhardt C - PLoS ONE (2014)

Bottom Line: The frequent emergence of new influenza viruses in the human population underlines the urgent need for antiviral therapeutics in addition to the preventative vaccination against the seasonal flu.Inhibition of Rac1 by NSC23766 resulted in impaired replication of a wide variety of influenza viruses, including a human virus strain of the pandemic from 2009 as well as highly pathogenic avian virus strains.Furthermore, we identified a crucial role of Rac1 for the activity of the viral polymerase complex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Virology (IMV), Centre of Molecular Virology (ZMBE), Westfälische Wilhelms-University, Münster, Germany.

ABSTRACT
The frequent emergence of new influenza viruses in the human population underlines the urgent need for antiviral therapeutics in addition to the preventative vaccination against the seasonal flu. To circumvent the development of resistance, recent antiviral approaches target cellular proteins needed by the virus for efficient replication. We investigated the contribution of the small GTPase Rac1 to the replication of influenza viruses. Inhibition of Rac1 by NSC23766 resulted in impaired replication of a wide variety of influenza viruses, including a human virus strain of the pandemic from 2009 as well as highly pathogenic avian virus strains. Furthermore, we identified a crucial role of Rac1 for the activity of the viral polymerase complex. The antiviral potential of NSC23766 was confirmed in mouse experiments, identifying Rac1 as a new cellular target for therapeutic treatment of influenza virus infections.

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NSC23766 does not cause cytotoxic side-effects on A549 cells.A549 cells were treated with the indicated concentrations of NSC23766 or staurosporine (1 µM), which served as a positive control. After 10, 24, or 32 h incubation, metabolic activity was measured via MTT assay (A). The onset of apoptosis was analyzed after 24 h incubation either by the detection of PARP cleavage in Western blot analysis (B) or by propidium iodide staining (C). Cell proliferation was determined after indicated incubation times by usage of the cell proliferation reagent WST-1 detecting the absorbance at 450 nm (D). Data represent means ± SD of three independent experiments including four (A) or two (C) biological samples or means ± SD of three biological samples of one representative out of three conducted experiments (D).
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pone-0088520-g002: NSC23766 does not cause cytotoxic side-effects on A549 cells.A549 cells were treated with the indicated concentrations of NSC23766 or staurosporine (1 µM), which served as a positive control. After 10, 24, or 32 h incubation, metabolic activity was measured via MTT assay (A). The onset of apoptosis was analyzed after 24 h incubation either by the detection of PARP cleavage in Western blot analysis (B) or by propidium iodide staining (C). Cell proliferation was determined after indicated incubation times by usage of the cell proliferation reagent WST-1 detecting the absorbance at 450 nm (D). Data represent means ± SD of three independent experiments including four (A) or two (C) biological samples or means ± SD of three biological samples of one representative out of three conducted experiments (D).

Mentions: Since the use of drugs targeting cellular factors may raise concerns about side effects on the host cell, we analyzed whether antiviral-acting concentrations of NSC23766 show harmful effects on cell health (Fig. 2). To investigate the impact of NSC23766 treatment on the metabolism of A549 cells, MTT assays were performed after 10, 24 and 32 h inhibitor treatment (Fig. 2A). The onset of apoptosis was evaluated after 24 h by detection of PARP cleavage in Western blot analysis (Fig. 2B) or measurement of DNA degradation via propidium iodide staining (Fig. 2C). Concentrations of up to 100 µM showed no severe effect on the metabolic activity (Fig. 2A) or apoptosis (Fig. 2B–C), while higher concentrations of 150 µM or 200 µM resulted in slightly reduced metabolic activity and enhanced apoptosis.


The Rac1 inhibitor NSC23766 exerts anti-influenza virus properties by affecting the viral polymerase complex activity.

Dierkes R, Warnking K, Liedmann S, Seyer R, Ludwig S, Ehrhardt C - PLoS ONE (2014)

NSC23766 does not cause cytotoxic side-effects on A549 cells.A549 cells were treated with the indicated concentrations of NSC23766 or staurosporine (1 µM), which served as a positive control. After 10, 24, or 32 h incubation, metabolic activity was measured via MTT assay (A). The onset of apoptosis was analyzed after 24 h incubation either by the detection of PARP cleavage in Western blot analysis (B) or by propidium iodide staining (C). Cell proliferation was determined after indicated incubation times by usage of the cell proliferation reagent WST-1 detecting the absorbance at 450 nm (D). Data represent means ± SD of three independent experiments including four (A) or two (C) biological samples or means ± SD of three biological samples of one representative out of three conducted experiments (D).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3921225&req=5

pone-0088520-g002: NSC23766 does not cause cytotoxic side-effects on A549 cells.A549 cells were treated with the indicated concentrations of NSC23766 or staurosporine (1 µM), which served as a positive control. After 10, 24, or 32 h incubation, metabolic activity was measured via MTT assay (A). The onset of apoptosis was analyzed after 24 h incubation either by the detection of PARP cleavage in Western blot analysis (B) or by propidium iodide staining (C). Cell proliferation was determined after indicated incubation times by usage of the cell proliferation reagent WST-1 detecting the absorbance at 450 nm (D). Data represent means ± SD of three independent experiments including four (A) or two (C) biological samples or means ± SD of three biological samples of one representative out of three conducted experiments (D).
Mentions: Since the use of drugs targeting cellular factors may raise concerns about side effects on the host cell, we analyzed whether antiviral-acting concentrations of NSC23766 show harmful effects on cell health (Fig. 2). To investigate the impact of NSC23766 treatment on the metabolism of A549 cells, MTT assays were performed after 10, 24 and 32 h inhibitor treatment (Fig. 2A). The onset of apoptosis was evaluated after 24 h by detection of PARP cleavage in Western blot analysis (Fig. 2B) or measurement of DNA degradation via propidium iodide staining (Fig. 2C). Concentrations of up to 100 µM showed no severe effect on the metabolic activity (Fig. 2A) or apoptosis (Fig. 2B–C), while higher concentrations of 150 µM or 200 µM resulted in slightly reduced metabolic activity and enhanced apoptosis.

Bottom Line: The frequent emergence of new influenza viruses in the human population underlines the urgent need for antiviral therapeutics in addition to the preventative vaccination against the seasonal flu.Inhibition of Rac1 by NSC23766 resulted in impaired replication of a wide variety of influenza viruses, including a human virus strain of the pandemic from 2009 as well as highly pathogenic avian virus strains.Furthermore, we identified a crucial role of Rac1 for the activity of the viral polymerase complex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Virology (IMV), Centre of Molecular Virology (ZMBE), Westfälische Wilhelms-University, Münster, Germany.

ABSTRACT
The frequent emergence of new influenza viruses in the human population underlines the urgent need for antiviral therapeutics in addition to the preventative vaccination against the seasonal flu. To circumvent the development of resistance, recent antiviral approaches target cellular proteins needed by the virus for efficient replication. We investigated the contribution of the small GTPase Rac1 to the replication of influenza viruses. Inhibition of Rac1 by NSC23766 resulted in impaired replication of a wide variety of influenza viruses, including a human virus strain of the pandemic from 2009 as well as highly pathogenic avian virus strains. Furthermore, we identified a crucial role of Rac1 for the activity of the viral polymerase complex. The antiviral potential of NSC23766 was confirmed in mouse experiments, identifying Rac1 as a new cellular target for therapeutic treatment of influenza virus infections.

Show MeSH
Related in: MedlinePlus