Atovaquone Inhibits Arbovirus Replication through the Depletion of Intracellular Nucleotides

Abstract

Arthropod-borne viruses represent a significant public health threat worldwide, yet there are few antiviral therapies or prophylaxes targeting these pathogens. In particular, the development of novel antivirals for high-risk populations such as pregnant women is essential to prevent devastating disease such as that which was experienced with the recent outbreak of Zika virus (ZIKV) in the Americas. One potential avenue to identify new and pregnancy-acceptable antiviral compounds is to repurpose well-known and widely used FDA-approved drugs. In this study, we addressed the antiviral role of atovaquone, an FDA Pregnancy Category C drug and pyrimidine biosynthesis inhibitor used for the prevention and treatment of parasitic infections. We found that atovaquone was able to inhibit ZIKV and chikungunya virus virion production in human cells and that this antiviral effect occurred early during infection at the initial steps of viral RNA replication. Moreover, we were able to complement viral replication and virion production with the addition of exogenous pyrimidine nucleosides, indicating that atovaquone functions through the inhibition of the pyrimidine biosynthesis pathway to inhibit viral replication. Finally, using an ex vivo human placental tissue model, we found that atovaquone could limit ZIKV infection in a dose-dependent manner, providing evidence that atovaquone may function as an antiviral in humans. Taken together, these studies suggest that atovaquone could be a broad-spectrum antiviral drug and a potential attractive candidate for the prophylaxis or treatment of arbovirus infection in vulnerable populations, such as pregnant women and children.IMPORTANCE The ability to protect vulnerable populations such as pregnant women and children from Zika virus and other arbovirus infections is essential to preventing the devastating complications induced by these viruses. One class of antiviral therapies may lie in known pregnancy-acceptable drugs that have the potential to mitigate arbovirus infections and disease, yet this has not been explored in detail. In this study, we show that the common antiparasitic drug atovaquone inhibits arbovirus replication through intracellular nucleotide depletion and can impair ZIKV infection in an ex vivo human placental explant model. Our study provides a novel function for atovaquone and highlights that the rediscovery of pregnancy-acceptable drugs with potential antiviral effects can be the key to better addressing the immediate need for treating viral infections and preventing potential birth complications and future disease.

The Use of Antimalarial Drugs against Viral Infection

“…In the same paper, Kottkamp and colleagues evaluated the ability of atovaquone to reduce the infectivity of both a Brazilian and a Ugandan strain of ZIKV by immunostaining the envelope after treatment and infection and subsequent plaque assay in different cells. These data were further confirmed ex vivo in a human placenta tissue model, with a dose-dependent reduction in infection and virion production by the Ugandan strain [166].…”

“…Flaviviridae BVDV(surrogate HCV) Artemisinin in vitro [187,188] Dihydroartemisinin in vitro [63] HCV Artemisinin in vitro [20][21][22] Artesunate in vitro [57] Chloroquine in vitro [148][149][150] ZIKV Mefloquine in vitro [130,131] Chloroquine in vitro [140,141] Amodiaquine in vitro [140] Atovaquone in vitro [166] DENV Quinine sulfate in vitro [66] Mefloquine in vitro [131] Halofantrine in vitro [134] Doxycycline in vitro [168,178] Amodiaquine in vitro [162] CHIKV Doxycycline in vitro [169] Chloroquine in vitro [37,138,139] Atovaquone in vitro [166] Togaviridae SFV Halofantrine in vitro [134] Rhabdoviridae VSV Doxycycline in vitro [170] Orthomyxoviridae IAV Quinine sulfate in vitro [70] In vivo (mouse) [67] Mefloquine in vitro [70] Doxycycline in vivo (mouse) [171] Chloroquine in vitro [159]…”

Mapping the evolutionary landscape of Zika virus infection in immunocompromised mice

“…Viral titers were determined by plaque assay on Vero cells (Cifuentes Kottkamp et al, 2019). In brief, virus was subjected to ten-fold serial dilutions in DMEM and added to a monolayer of Vero cells for one hour at 37°C.…”

Antiviral Strategies against Arthritogenic Alphaviruses

“…Consequently, 6-azauridine inhibits the replication of several viruses, including CHIKV and SFV [ 69 ]. The antiparasitic drug atovaquone ( Figure 3 ) has also been shown to inhibit the replication of CHIKV in a dose-dependent manner [ 70 ]. The observed antiviral activity of atovaquone is suggested to be due to the inhibition of de novo pyrimidine biosynthesis [ 70 ].…”