Bst2/Tetherin Is Induced in Neurons by Type I Interferon and Viral Infection but Is Dispensable for Protection against Neurotropic Viral Challenge

Abstract

In permissive mouse central nervous system (CNS) neurons, measles virus (MV) spreads in the absence of hallmark viral budding or neuronal death, with transmission occurring efficiently and exclusively via the synapse. MV infection also initiates a robust type I interferon (IFN) response, resulting in the synthesis of a large number of genes, including bone marrow stromal antigen 2 (Bst2)/tetherin/CD317. Bst2 restricts the release of some enveloped viruses, but to date, its role in viral infection of neurons has not been assessed. Consequently, we investigated how Bst2 was induced and what role it played in MV neuronal infection. The magnitude of induction of neuronal Bst2 RNA and protein following IFN exposure and viral infection was notably higher than in similarly treated mouse embryo fibroblasts (MEFs). Bst2 synthesis was both IFN and Stat1 dependent. Although Bst2 prevented MV release from nonneuronal cells, its deletion had no effect on viral pathogenesis in MV-challenged mice. Our findings underscore how cell-type-specific differences impact viral infection and pathogenesis. IMPORTANCE Viral infections of the central nervous system can lead to debilitating disease and death. Moreover, it is becoming increasingly clear that nonrenewable cells, including most central nervous system neurons, combat neurotropic viral infections in fundamen-tally different ways than other rapidly dividing and renewable cell populations. Here we identify type I interferon signaling as a key inducer of a known antiviral protein (Bst2) in neurons. Unexpectedly, the gene is dispensable for clearance of neurotropic viral infection despite its well-defined contribution to limiting the spread of enveloped viruses in proliferating cells. A deeper appreciation of the importance of cell type heterogeneity in antiviral immunity will aid in the identification of unique therapeutic targets for life-threatening viral infections. Many of the foundational principles in immunology have resulted from basic observations of virus-cell interactions, including the induction and antiviral function of both type I and type II interferons (IFNs) (reviewed in references 1, 2, and 3). Viral infection of a cell typically results in cellular production and secretion of type I IFNs, which can then bind to cell surface receptors in a paracrine and autocrine fashion, leading to synthesis of interferon-stimulated genes (ISGs). These ISGs, in turn, aid in clearing the viral infection by directly cleaving viral nucleic acids, triggering cellular apoptosis, inducing autophagy, upregulating major histocompatibility complex (MHC) class I expression to aid in CD8 ϩ T cell-mediated cytotoxicity, and preventing viral egress. Moreover, the induction of type I IFN contributes to the recruitment of adaptive immune effectors to infected sites, which further promotes viral clearance.One ISG that is highly induced following infection by many viruses, and in response to both type I and II IFN signaling, is the gene for bone marrow stromal antigen 2 (Bst2; also known a...

Analysis of tick-borne encephalitis virus-induced host responses in human cells of neuronal origin and interferon-mediated protection

“…Therefore it may be that lncRNAs play an important role in IFN-stimulated host immune responses to viral infection. This hypothesis was recently supported by the identification of an IFN-l3 up-regulated lncBST2/BISPR that positively regulates expression of BST2/tetherin [67], an ISG with antiviral effect in murine neurons against measles virus [68]. Further studies are required to elucidate the possible involvement of host lncRNAs in response to TBEV infection.…”

A STING-dependent innate-sensing pathway mediates resistance to corneal HSV-1 infection via upregulation of the antiviral effector tetherin

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