Replication of Equine arteritis virus is efficiently suppressed by purine and pyrimidine biosynthesis inhibitors

Abstract

RNA viruses are responsible for a large variety of animal infections. Equine Arteritis Virus (EAV) is a positive single-stranded RNA virus member of the family Arteriviridae from the order Nidovirales like the Coronaviridae. EAV causes respiratory and reproductive diseases in equids. Although two vaccines are available, the vaccination coverage of the equine population is largely insufficient to prevent new EAV outbreaks around the world. In this study, we present a high-throughput in vitro assay suitable for testing candidate antiviral molecules on equine dermal cells infected by EAV. Using this assay, we identified three molecules that impair EAV infection in equine cells: the broad-spectrum antiviral and nucleoside analog ribavirin, and two compounds previously described as inhibitors of dihydroorotate dehydrogenase (DHODH), the fourth enzyme of the pyrimidine biosynthesis pathway. These molecules effectively suppressed cytopathic effects associated to EAV infection, and strongly inhibited viral replication and production of infectious particles. Since ribavirin is already approved in human and small animal, and that several DHODH inhibitors are in advanced clinical trials, our results open new perspectives for the management of EAV outbreaks. Viruses with a RNA genome infect both animals and plants, and dominate the eukaryotic virome by their diversity and deleterious effects 1. Indeed, RNA viral infections are a substantial public health burden affecting humans and domestic animals 2. The pandemic of SARS-CoV-2 coronavirus is the latest and most striking example with thousands of deaths reported so far in different countries in the world. Horses are not an exception, and five of seven equine viruses listed by the World Organization for Animal Health are RNA viruses (OIE). Unfortunately, the veterinary therapeutic arsenal to fight against equine viral diseases is limited, or even not-existent as no antiviral molecule is listed today. During the last years, several studies have used high-throughput screening (HTS) techniques to scan small compound libraries that could impair the replication of equine viruses. These studies were mostly focused on zoonotic viruses like West-Nile virus 3,4. Non-zoonotic equine RNA viruses, such as equine arteritis virus (EAV), were not included in those screenings. Equine arteritis virus (EAV) is a positive-sense single-stranded RNA virus, member of the subfamily Equarterivirinae, member of the family Arteriviridae, genus Alphaarterivirus from order Nidovirales like the Coronaviridae. Equine viral arteritis disease is a recurrent viral infection that causes important economic losses to the horse industry. In most of the cases, EAV infection is subclinical, but some viral strains are virulent and induce fever with body temperature going up to 41 °C, depression, anorexia, edema, nasal discharge, and conjunctivitis. EAV is a virus transmitted by respiratory or venereal routes.

Regulation of the pyrimidine biosynthetic pathway by lysine acetylation of E. coliOPRTase

“…Furthermore, the upregulation of some enzymes in this pathway indicates a poor prognosis in cancer patients, hence these genes are attractive anticancer drugs to inhibit proliferation and metastasis [ 16 , 17 , 18 , 19 ]. Likewise, viral replication relies on the host to supply nucleotides, thus the enzymes in this pathway are targets for antiviral treatments [ 20 , 21 , 22 , 23 ]. Moreover, the inhibition of pyrimidine biosynthesis enzymes is employed for the treatment of microorganism and parasite infections [ 24 , 25 , 26 , 27 ].…”

An equine iPSC-based phenotypic screening platform identifies pro- and anti-viral molecules against West Nile virus

“…The antiviral activity of direct-acting and host-directed antivirals has generally been evidenced using cell lines of rodent or primate origin, models that may be poorly predictive of therapeutic efficacy in horses. Equine dermal cells (ED) have been used to test antivirals against equine arteritis virus [9] and equine herpes virus [10], but are unsuitable for study of WNV as they are weakly permissive to WNV (personal observation). Equine brain cells would represent a more relevant model, as WNV disease results from brain infection.…”

Role of vaccinia virus growth factor in stimulating the mTORC1-CAD axis of thede novopyrimidine pathway under different nutritional cues

“…Recent studies suggest that some viruses enhance the synthesis of nucleotides to facilitate replication [28][29][30] . Earlier research has demonstrated that VACV replication was reduced when treated with N-phosphonacetyl-L-aspartate (PALA), an inhibitor of the de novo pyrimidine pathway 31 .…”