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The Viral Polymerase Inhibitor 7-Deaza-2'-C-Methyladenosine Is a Potent Inhibitor of In Vitro Zika Virus Replication and Delays Disease Progression in a Robust Mouse Infection Model.

Zmurko J, Marques RE, Schols D, Verbeken E, Kaptein SJ, Neyts J - PLoS Negl Trop Dis (2016)

Bottom Line: Zika virus (ZIKV) is an emerging flavivirus typically causing a dengue-like febrile illness, but neurological complications, such as microcephaly in newborns, have potentially been linked to this viral infection.We established a panel of in vitro assays to allow the identification of ZIKV inhibitors and demonstrate that the viral polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA) efficiently inhibits replication.Infection of AG129 (IFN-α/β and IFN-γ receptor knock-out) mice with ZIKV resulted in acute neutrophilic encephalitis with viral antigens accumulating in neurons of the brain and spinal cord.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Virology and Chemotherapy, KU Leuven - University of Leuven, Leuven, Belgium.

ABSTRACT
Zika virus (ZIKV) is an emerging flavivirus typically causing a dengue-like febrile illness, but neurological complications, such as microcephaly in newborns, have potentially been linked to this viral infection. We established a panel of in vitro assays to allow the identification of ZIKV inhibitors and demonstrate that the viral polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA) efficiently inhibits replication. Infection of AG129 (IFN-α/β and IFN-γ receptor knock-out) mice with ZIKV resulted in acute neutrophilic encephalitis with viral antigens accumulating in neurons of the brain and spinal cord. Additionally, high levels of viral RNA were detected in the spleen, liver and kidney, and levels of IFN-γ and IL-18 were systematically increased in serum of ZIKV-infected mice. Interestingly, the virus was also detected in testicles of infected mice. In line with its in vitro anti-ZIKV activity, 7DMA reduced viremia and delayed virus-induced morbidity and mortality in infected mice, which also validates this small animal model to assess the in vivo efficacy of novel ZIKV inhibitors. Since AG129 mice can generate an antibody response, and have been used in dengue vaccine studies, the model can also be used to assess the efficacy of ZIKV vaccines.  .

No MeSH data available.


Related in: MedlinePlus

Presence of ZIKV antigens in the brain (A), spinal cord (D) and liver (E) of ZIKV-infected AG129 mice, whereas ZIKV antigens were absent in tissues of uninfected mice (brain, B), as shown by histopathological analysis.Infiltration of neutrophils is shown in the brain of ZIKV-infected mice (as detected by hematoxylin-eosin staining; C), but not in the brain of uninfected mice (F).
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pntd.0004695.g004: Presence of ZIKV antigens in the brain (A), spinal cord (D) and liver (E) of ZIKV-infected AG129 mice, whereas ZIKV antigens were absent in tissues of uninfected mice (brain, B), as shown by histopathological analysis.Infiltration of neutrophils is shown in the brain of ZIKV-infected mice (as detected by hematoxylin-eosin staining; C), but not in the brain of uninfected mice (F).

Mentions: Intraperitoneal inoculation of IFN-α/β and IFN-γ receptor knockout mice (AG129) with as low as 200 μL of a 1×101 PFU/ml stock of ZIKV resulted in virus-induced disease (see below) and mice had to be euthanized at a MDE (mean day of euthanasia) of 18.5 days pi (Fig 3A). Infection with higher inoculums (1×102–1×105 PFU/ml; 200 μL) resulted in a faster progression of the disease (MDE of 14 days pi) with the first signs of disease appearing at day 10 pi. Surprisingly, inoculation of SCID mice with 200 μL of a 1×104 PFU/ml stock of ZIKV resulted in delayed disease; SCID mice had to be euthanized at day 40.0 ± 4.4 pi, roughly 26 days later than AG129 mice (S3 Fig). Disease signs in AG129 mice included paralysis of the lower limbs, body weight loss, hunched back and conjunctivitis. High levels of viral RNA were detected in brain, spleen, liver and kidney from mice that were euthanized at day 13–15 pi (Fig 3B). Histopathological analysis on tissues collected at day 13–15 pi revealed the accumulation of viral antigens in neurons of both the brain (Fig 4A) and the spinal cord (Fig 4D) as well as in hepatocytes (Fig 4E). Acute neutrophilic encephalitis (Fig 4C) was observed at the time of onset of virus-induced morbidity. It was next assessed whether infection with ZIKV resulted in the induction of a panel of 20 cytokines and chemokines at different time points pi (day 2, 3, 4 and 8; Figs 3C and 3D and S4A–S4G). In particular, levels of IFN-γ and IL-18 were increased systematically and significantly during the course of infection (Fig 3C and 3D), whereas levels of IL-6, CCL2, CCL5, CCL7, CXCL1, CXCL10 and TNF-α first increased, reaching a peak level at day 3 pi (CCL2, CXCL1, TNF-α; S4A–S4C Fig) or day 4 pi (IL-6, CCL7, CXCL10; S4D–S4F Fig) pi and then gradually declined. Levels of CCL5 subsequently increased at day 2 pi, dropped at day 3 pi, and gradually increased again at day 4 and 8 pi (S4G Fig).


The Viral Polymerase Inhibitor 7-Deaza-2'-C-Methyladenosine Is a Potent Inhibitor of In Vitro Zika Virus Replication and Delays Disease Progression in a Robust Mouse Infection Model.

Zmurko J, Marques RE, Schols D, Verbeken E, Kaptein SJ, Neyts J - PLoS Negl Trop Dis (2016)

Presence of ZIKV antigens in the brain (A), spinal cord (D) and liver (E) of ZIKV-infected AG129 mice, whereas ZIKV antigens were absent in tissues of uninfected mice (brain, B), as shown by histopathological analysis.Infiltration of neutrophils is shown in the brain of ZIKV-infected mice (as detected by hematoxylin-eosin staining; C), but not in the brain of uninfected mice (F).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862633&req=5

pntd.0004695.g004: Presence of ZIKV antigens in the brain (A), spinal cord (D) and liver (E) of ZIKV-infected AG129 mice, whereas ZIKV antigens were absent in tissues of uninfected mice (brain, B), as shown by histopathological analysis.Infiltration of neutrophils is shown in the brain of ZIKV-infected mice (as detected by hematoxylin-eosin staining; C), but not in the brain of uninfected mice (F).
Mentions: Intraperitoneal inoculation of IFN-α/β and IFN-γ receptor knockout mice (AG129) with as low as 200 μL of a 1×101 PFU/ml stock of ZIKV resulted in virus-induced disease (see below) and mice had to be euthanized at a MDE (mean day of euthanasia) of 18.5 days pi (Fig 3A). Infection with higher inoculums (1×102–1×105 PFU/ml; 200 μL) resulted in a faster progression of the disease (MDE of 14 days pi) with the first signs of disease appearing at day 10 pi. Surprisingly, inoculation of SCID mice with 200 μL of a 1×104 PFU/ml stock of ZIKV resulted in delayed disease; SCID mice had to be euthanized at day 40.0 ± 4.4 pi, roughly 26 days later than AG129 mice (S3 Fig). Disease signs in AG129 mice included paralysis of the lower limbs, body weight loss, hunched back and conjunctivitis. High levels of viral RNA were detected in brain, spleen, liver and kidney from mice that were euthanized at day 13–15 pi (Fig 3B). Histopathological analysis on tissues collected at day 13–15 pi revealed the accumulation of viral antigens in neurons of both the brain (Fig 4A) and the spinal cord (Fig 4D) as well as in hepatocytes (Fig 4E). Acute neutrophilic encephalitis (Fig 4C) was observed at the time of onset of virus-induced morbidity. It was next assessed whether infection with ZIKV resulted in the induction of a panel of 20 cytokines and chemokines at different time points pi (day 2, 3, 4 and 8; Figs 3C and 3D and S4A–S4G). In particular, levels of IFN-γ and IL-18 were increased systematically and significantly during the course of infection (Fig 3C and 3D), whereas levels of IL-6, CCL2, CCL5, CCL7, CXCL1, CXCL10 and TNF-α first increased, reaching a peak level at day 3 pi (CCL2, CXCL1, TNF-α; S4A–S4C Fig) or day 4 pi (IL-6, CCL7, CXCL10; S4D–S4F Fig) pi and then gradually declined. Levels of CCL5 subsequently increased at day 2 pi, dropped at day 3 pi, and gradually increased again at day 4 and 8 pi (S4G Fig).

Bottom Line: Zika virus (ZIKV) is an emerging flavivirus typically causing a dengue-like febrile illness, but neurological complications, such as microcephaly in newborns, have potentially been linked to this viral infection.We established a panel of in vitro assays to allow the identification of ZIKV inhibitors and demonstrate that the viral polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA) efficiently inhibits replication.Infection of AG129 (IFN-α/β and IFN-γ receptor knock-out) mice with ZIKV resulted in acute neutrophilic encephalitis with viral antigens accumulating in neurons of the brain and spinal cord.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Virology and Chemotherapy, KU Leuven - University of Leuven, Leuven, Belgium.

ABSTRACT
Zika virus (ZIKV) is an emerging flavivirus typically causing a dengue-like febrile illness, but neurological complications, such as microcephaly in newborns, have potentially been linked to this viral infection. We established a panel of in vitro assays to allow the identification of ZIKV inhibitors and demonstrate that the viral polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA) efficiently inhibits replication. Infection of AG129 (IFN-α/β and IFN-γ receptor knock-out) mice with ZIKV resulted in acute neutrophilic encephalitis with viral antigens accumulating in neurons of the brain and spinal cord. Additionally, high levels of viral RNA were detected in the spleen, liver and kidney, and levels of IFN-γ and IL-18 were systematically increased in serum of ZIKV-infected mice. Interestingly, the virus was also detected in testicles of infected mice. In line with its in vitro anti-ZIKV activity, 7DMA reduced viremia and delayed virus-induced morbidity and mortality in infected mice, which also validates this small animal model to assess the in vivo efficacy of novel ZIKV inhibitors. Since AG129 mice can generate an antibody response, and have been used in dengue vaccine studies, the model can also be used to assess the efficacy of ZIKV vaccines.  .

No MeSH data available.


Related in: MedlinePlus