Pteropine orthoreoviruses use cell surface heparan sulphate as an attachment receptor

ABSTRACT

Pteropine orthoreoviruses (PRVs) are an emerging group of fusogenic, bat-borne viruses from the Orthoreovirus genus. Since the isolation of PRV from a patient with acute respiratory tract infections in 2006, the zoonotic potential of PRV has been further highlighted following subsequent isolation of PRV species from patients in Malaysia, Hong Kong and Indonesia. However, the entry mechanism of PRV is currently unknown. In this study, we investigated the role of previously identified mammalian orthoreovirus (MRV) receptors, sialic acid and junctional adhesion molecule-1 for PRV infection. However, none of these receptors played a significant role in PRV infection, suggesting PRV uses a distinct entry receptor from MRV. Given its broad tissue tropism, we hypothesized that PRV may use a receptor that is widely expressed in all cell types, heparan sulphate (HS). Enzymatic removal of cell surface HS by heparinase treatment and genetic ablation of HS biosynthesis genes, SLC35B2, exostosin-1, N-deacetylase/N-sulfotransferase I and beta-1,3-glucuronyltransferase 3, significantly reduced infection with multiple genetically distinct PRV species. Replication kinetic of PRV3M in HS knockout cells revealed that HS plays a crucial role in the early phase of PRV infection. Mechanistic studies demonstrated that HS is an essential host-factor for PRV attachment and internalization into cells. To our knowledge, this is the first report on the use of HS as an attachment receptor by PRVs.

KEYWORDS:

• Pteropine orthoreovirus
• heparan sulphate
• attachment receptor
• Melaka virus
• glycosaminoglycans

Acknowledgement

This work is supported in part by grants from Singapore National Research Foundation (NRF2016NRF-NSFC002-013, awarded to WLF) and the National Medical Research Council (MOH-00535/MOH-OFYIRGnov-0002, awarded to TCW).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Medical Research Council [Grant Number MOH-00535/MOH-OFYIRGnov-0002] and National Research Foundation Singapore [Grant Number NRF2018NRF-NSFC003SB-002].