Porcine Sapelovirus Uses α2,3-Linked Sialic Acid on GD1a Ganglioside as a Receptor

Abstract

The receptor(s) for porcine sapelovirus (PSV), which causes diarrhea, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs, remains largely unknown. Given the precedent for other picornaviruses which use terminal sialic acids (SAs) as receptors, we examined the role of SAs in PSV binding and infection. Using a variety of approaches, including treating cells with a carbohydrate-destroying chemical (NaIO4), mono- or oligosaccharides (N-acetylneuraminic acid, galactose, and 6′-sialyllactose), linkage-specific sialidases (neuraminidase and sialidase S), lectins (Maakia amurensis lectin and Sambucus nigra lectin), proteases (trypsin and chymotrypsin), and glucosylceramide synthase inhibitors (dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol and phospholipase C), we demonstrated that PSV could recognize α2,3-linked SA on glycolipids as a receptor. On the other hand, PSVs had no binding affinity for synthetic histo-blood group antigens (HBGAs), suggesting that PSVs could not use HBGAs as receptors. Depletion of cell surface glycolipids followed by reconstitution studies indicated that GD1a ganglioside, but not other gangliosides, could restore PSV binding and infection, further confirming α2,3-linked SA on GD1a as a PSV receptor. Our results could provide significant information on the understanding of the life cycle of sapelovirus and other picornaviruses. For the broader community in the area of pathogens and pathogenesis, these findings and insights could contribute to the development of affordable, useful, and efficient drugs for anti-sapelovirus therapy.IMPORTANCE The porcine sapelovirus (PSV) is known to cause enteritis, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs. However, the receptor(s) that the PSV utilizes to enter host cells remains largely unknown. Using a variety of approaches, we showed that α2,3-linked terminal sialic acid (SA) on the cell surface GD1a ganglioside could be used for PSV binding and infection as a receptor. On the other hand, histo-blood group antigens also present in the cell surface carbohydrates could not be utilized as PSV receptors for binding and infection. These findings should contribute to the understanding of the sapelovirus life cycle and to the development of affordable, useful and efficient drugs for anti-sapelovirus therapy.

Pathogenesis of Korean Sapelovirus A in piglets and chicks

“…Our previous results have demonstrated that SV-A could recognize α2,3-linked SA as a receptor (Kim et al , 2016), suggesting that SV-A might be able to infect and induce pathology in both pigs and chicks. To determine whether SV-A could induce diarrhoea and faecal viral shedding in piglets and chicks, 3-day-old piglets obtained from sows by hysterectomy and 3-day-old specific pathogen-free (SPF) chicks were orally inoculated with 2×10 9 or 5×10 8 p.f.u.…”

“…We have previously demonstrated that SV-A could utilize α2,3-linked SA on GD1a glycolipid as a receptor (Kim et al , 2016). Indeed, glycolipid-associated α2,3-terminal SA is abundant on the cell surface of both avian and porcine species (de Graaf & Fouchier, 2014; Raman et al , 2014).…”

“…Our results also suggested that other factors in addition to glycolipid-associated α2,3-terminal SA might be required for efficient SV-A replication in cells of non-porcine origin. We have previously observed that chymotrypsin or trypsin treatment of cells has no effect on virus infection (Kim et al , 2016), suggesting that cell surface-associated proteins do not play accessory roles in SV-A infection. The nature of post-binding block to infection in cells from non-porcine origin is as yet unknown, but it is possible the SV-A infection of avian cells induces the innate response leading to the restriction of viral replication.…”

“…SV-A can cause asymptomatic and symptomatic diseases in both field and experimental pigs (Alexandersen et al , 2012; Kim et al , 2016). The symptomatic disorders include diarrhoea, pneumonia, polioencephalomyelitis and reproductive disorders (Alexandersen et al , 2012; Huang et al , 1980; Lamont & Betts, 1960; Lan et al , 2011; Schock et al , 2014; Sibalin, 1963).…”

“…We have recently demonstrated that SV-A can recognize a2,3-linked sialic acid (SA) on GD1a as a functional SV-A receptor (Kim et al , 2016). a2,3-linked SA is known to be highly expressed on cells of porcine and avian origin (de Graaf & Fouchier, 2014; Raman et al , 2014), indicating that SV-A has the potential to infect both pigs and chickens.…”