Identification of Host Factors Involved in Borna Disease Virus Cell Entry through a Small Interfering RNA Functional Genetic Screen

Abstract

Borna disease virus (BDV), the prototypic member of the Bornaviridae family, within the order Mononegavirales, is highly neurotropic and constitutes an important model system for the study of viral persistence in the central nervous system (CNS) and associated disorders. The virus surface glycoprotein (G) has been shown to direct BDV cell entry via receptor-mediated endocytosis, but the mechanisms governing cell tropism and propagation of BDV within the CNS are unknown. We developed a small interfering RNA (siRNA)-based screening to identify cellular genes and pathways that specifically contribute to BDV G-mediated cell entry. Our screen relied on silencing-mediated increased survival of cells infected with rVSV⌬G*/BDVG, a cytolytic recombinant vesicular stomatitis virus expressing BDV G that mimics the cell tropism and entry pathway of bona fide BDV. We identified 24 cellular genes involved in BDV G-mediated cell entry. Identified genes are known to participate in a broad range of distinct cellular functions, revealing a complex process associated with BDV cell entry. The siRNA-based screening strategy we have developed should be applicable to identify cellular genes contributing to cell entry mediated by surface G proteins of other viruses. (12,49,51). However, based on its unique genetics and biological features, BDV is considered to be the prototypic member of a new virus family, Bornaviridae, within the order Mononegavirales (13, 49). BDV is highly neurotropic and causes central nervous system (CNS) disease in a variety of vertebrate species that is frequently manifested by behavioral abnormalities (25,53). Both host and viral factors contribute to a variable period of incubation and heterogeneity in the symptoms and pathology associated with BDV infection (18,20,32,44,46). BDV provides an important model for the investigation of both immune-mediated pathological events associated with virus-induced neurological disease and mechanisms whereby viruses induce neurodevelopmental and behavioral disturbances in the absence of the hallmarks of cytolysis and inflammation (19,24,42). Borna disease virus (BDV) is an enveloped virus with a nonsegmented negative-strand (NNS) RNA genome whose organization (3Ј-N-p10/P-M-G-L-5Ј) is characteristic of mononegaviruses (MNV)Serological data and molecular epidemiological studies suggest that BDV, or a BDV-like virus, can infect humans, and it might be associated with certain neuropsychiatric disorders (23,29). Moreover, the recent identification of an avian bornavirus (22, 45) underscores the prospect of finding other BDV-like emerging viruses of potential relevance to human health. The identification of host cell factors involved in BDV cell entry will contribute to a better understanding of BDV cell tropism and propagation within the CNS, a first and necessary step to elucidate the mechanisms by which BDV disrupts normal brain functions. Likewise, the development of effective antiviral strategies to combat bornavirus infections may be facilitated by targeting host cell fact...

A synthetic cannabinoid agonist promotes oligodendrogliogenesis during viral encephalitis in rats

“…The lack of effect may result from virus- or inflammatory-induced disruption of biological membrane/lipid raft integrity, and the consequent uncoupling of the interactions between metabotropic glutamate 5 (mGLUR5) and CB 1 receptors, which is known to affect 2-AG production (Uchimagashima et al 2007, Maccarrone et al, 2008; Maccarrone et al, 2009). Consistent with this hypothesis, lipid rafts are involved in BDV cell entry (Clemente et al, 2009; Clemente et al, 2010), and synaptic pathology and disruption of striatal synapses have been reported in more advanced BD (Gonzalez-Dunia et al, 2000; Solbrig et al, 2000). Nevertheless, our data indicate that the beneficial effects of WIN do not require the reversal of AEA deficit and suggest that the decreased endocannabinoid levels observed in the striatum of BD rats may be a correlate rather than a cause of BDV-induced inflammatory response.…”

Analysis of Borna Disease Virus Trafficking in Live Infected Cells by Using a Virus Encoding a Tetracysteine-Tagged P Protein

“…Thus, this recombinant virus clearly allows the visualization of BDV cell-to-cell transfer and its progressive transport to the nucleus. Recently, a small interfering RNA (siRNA)-based functional genetic screen allowed the identification of host cell factors involved in BDV entry (42). It may be interesting in the future to probe the identified target genes by live imaging using our TC-tagged virus.…”

Comprehensive analysis of endogenous bornavirus-like elements in eukaryote genomes

“…Interestingly, M also associates with vRNP in the host cell nucleus, suggesting that M is involved in viral replication or transport of viral components [15]. G is the viral envelope glycoprotein and is involved in BDV entry, involving virion attachment to an unknown receptor and fusion of the viral envelope and cell membrane to release the vRNP into the cell cytoplasm in association with host factors [16][17][18][19][20][21]. X is a multifunctional, non-structural protein that is essential for the viral replication cycle [22], and is known to be a regulator of viral polymerase activity and an inhibitor of apoptosis in the central nervous system [23 -25].…”