Heparan sulfate-dependent enhancement of henipavirus infection.

UNLABELLED: Nipah virus and Hendra virus are emerging, highly pathogenic, zoonotic paramyxoviruses that belong to the genus Henipavirus. They infect humans as well as numerous mammalian species. Both viruses use ephrin-B2 and -B3 as cell entry receptors, and following initial entry into an organism, they are capable of rapid spread throughout the host. We have previously reported that Nipah virus can use another attachment receptor, different from its entry receptors, to bind to nonpermissive circulating leukocytes, thereby promoting viral dissemination within the host. Here, this attachment molecule was identified as heparan sulfate for both Nipah virus and Hendra virus. Cells devoid of heparan sulfate were not able to mediate henipavirus trans-infection and showed reduced permissivity to infection. Virus pseudotyped with Nipah virus glycoproteins bound heparan sulfate and heparin but no other glycosaminoglycans in a surface plasmon resonance assay. Furthermore, heparin was able to inhibit the interaction of the viruses with the heparan sulfate and to block cell-mediated trans-infection of henipaviruses. Moreover, heparin was shown to bind to ephrin-B3 and to restrain infection of permissive cells in vitro. Consequently, treatment with heparin devoid of anticoagulant activity improved the survival of Nipah virus-infected hamsters. Altogether, these results reveal heparan sulfate as a new attachment receptor for henipaviruses and as a potential therapeutic target for the development of novel approaches against these highly lethal infections. IMPORTANCE: The Henipavirus genus includes two closely related, highly pathogenic paramyxoviruses, Nipah virus and Hendra virus, which cause elevated morbidity and mortality in animals and humans. Pathogenesis of both Nipah virus and Hendra virus infection is poorly understood, and efficient antiviral treatment is still missing. Here, we identified heparan sulfate as a novel attachment receptor used by both viruses to bind host cells. We demonstrate that heparin was able to inhibit the interaction of the viruses with heparan sulfate and to block cell-mediated trans-infection of henipaviruses. Moreover, heparin also bound to the viral entry receptor and thereby restricted infection of permissive cells in vitro. Consequently, heparin treatment improved survival of Nipah virus-infected hamsters. These results uncover an important role of heparan sulfate in henipavirus infection and open novel perspectives for the development of heparan sulfate-targeting therapeutic approaches for these emerging infections.

Type I interferon signaling protects mice from lethal henipavirus infection.

Hendra virus (HeV) and Nipah virus (NiV) are closely related, recently emerged paramyxoviruses that form Henipavirus genus and are capable of causing considerable morbidity and mortality in a number of mammalian species, including humans. However, in contrast to many other species and despite expression of functional virus entry receptors, mice are resistant to henipavirus infection. We report here the susceptibility of mice deleted for the type I interferon receptor (IFNAR-KO) to both HeV and NiV. Intraperitoneally infected mice developed fatal encephalitis, with pathology and immunohistochemical features similar to what was found in humans. Viral RNA was found in the majority of analyzed organs, and sublethally infected animals developed virus-specific neutralizing antibodies. Altogether, these results reveal IFNAR-KO mice as a new small animal model to study HeV and NiV pathogenesis, prophylaxis, and treatment and suggest the critical role of type I interferon signaling in the control of henipavirus infection.