Permissivity of Dipeptidyl Peptidase 4 Orthologs to Middle East Respiratory Syndrome Coronavirus Is Governed by Glycosylation and Other Complex Determinants

Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes dipeptidyl peptidase 4 (DPP4) as an entry receptor. While bat, camel, and human DPP4 support MERS-CoV infection, several DPP4 orthologs, including mouse, ferret, hamster, and guinea pig DPP4, do not. Previous work revealed that glycosylation of mouse DPP4 plays a role in blocking MERS-CoV infection. Here, we tested whether glycosylation also acts as a determinant of permissivity for ferret, hamster, and guinea pig DPP4. We found that, while glycosylation plays an important role in these orthologs, additional sequence and structural determinants impact their ability to act as functional receptors for MERS-CoV. These results provide insight into DPP4 species-specific differences impacting MERS-CoV host range and better inform our understanding of virus-receptor interactions associated with disease emergence and host susceptibility.IMPORTANCE MERS-CoV is a recently emerged zoonotic virus that is still circulating in the human population with an ϳ35% mortality rate. With no available vaccines or therapeutics, the study of MERS-CoV pathogenesis is crucial for its control and prevention. However, in vivo studies are limited because MERS-CoV cannot infect wildtype mice due to incompatibilities between the virus spike and the mouse host cell receptor, mouse DPP4 (mDPP4). Specifically, mDPP4 has a nonconserved glycosylation site that acts as a barrier to MERS-CoV infection. Thus, one mouse model strategy has been to modify the mouse genome to remove this glycosylation site. Here, we investigated whether glycosylation acts as a barrier to infection for other nonpermissive small-animal species, namely, ferret, guinea pig, and hamster. Understanding the virus-receptor interactions for these DPP4 orthologs will help in the development of additional animal models while also revealing speciesspecific differences impacting MERS-CoV host range.KEYWORDS MERS-coronavirus, DPP4, orthologs, host range expansion, animal models, glycosylation, host range C oronaviruses are a diverse family of viruses that infect a wide range of hosts, including both mammalian and avian species. Phylogenetic studies suggest that over the last 800 years, several zoonotic coronaviruses have expanded their host range into humans, resulting in four antigenically distinct strains that are still circulating in the human population (1, 2). Whereas most human coronaviruses cause only mild symptoms in healthy adults, two recent emergence events have resulted in severe disease in humans. Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged from its

Single cell RNA sequencing of 13 human tissues identify cell types and receptors of human coronaviruses

“…After calculating their gene expression similarity, we found ANPEP, ENPEP and DPP4 are top three genes correlated with ACE4 (R > 0.8). Interestingly, both ANPEP and DPP4 are viral receptors of human coronaviruses [32], while ENPEP is also a peptidase, despite that its involvement in virus infection is unclear. For mysterious reasons, human coronaviruses use peptidases as their receptors [24].…”

Adaptive Evolution of MERS-CoV to Species Variation in DPP4

“…Notably, these two bat DPP4 sequences varied from human DPP4 and from each other at other positions in the receptor binding domain ( Figure S3B), suggesting that additional DPP4 residues can influence the interaction with spike. Forced adaptation of MERS-CoV spike has been a challenge in the field as DPP4 from most non-permissive species contains glycosylation that completely abrogates the interaction and blocks infection (Cockrell et al, 2014;Peck et al, 2015;Peck et al, 2017). Without viral replication, it has not been possible to experimentally demonstrate evolution of the MERS-CoV spike.…”

“…Our group has previously demonstrated that hamster DPP4 contains variation in these contact points, which prevents MERS-CoV replication (van van Doremalen et al, 2016). Other genetic variation responsible for the glycosylation of DPP4 in mice, hamsters, ferrets, and guinea pigs forms an additional block to the interaction with MERS-CoV spike (Cockrell et al, 2014;Peck et al, 2017). In contrast to small rodents and ferrets, MERS-CoV is capable of utilizing DPP4 from different bat species, and Artibeus jamaicensis bats have been shown to support experimental infection (Caì et al, 2014;Munster et al, 2016).…”

Origin and evolution of pathogenic coronaviruses

“…Like the interactions between SARS-CoV and ACE2, the interactions between MERS-CoV and DPP4 have been extensively examined. DPP4 from humans, camels, horses and bats can function as a receptor for MERS-CoV, whereas DPP4 from mice, hamsters and ferrets cannot 112,[122][123][124][125] . Key residue differences between human DPP4 and the DPP4 from other species affect the species specificities of MERS-CoV.…”