Interferon-induced Protein-44 and Interferon-induced Protein 44-like restrict replication of Respiratory Syncytial Virus

Abstract

24Cellular intrinsic immunity, mediated by the expression of an array of interferon-25 stimulated antiviral genes, is a vital part of host defence. We have previously used a 26 bioinformatic screen to identify two interferon stimulated genes (ISG) with poorly 27 characterised function, Interferon-induced protein 44 (IFI44) and interferon-induced 28 protein 44-like (IFI44L), as potentially being important in Respiratory Syncytial Virus 29 (RSV) infection. Using overexpression systems, CRISPR-Cas9-mediated knockout, 30 and a knockout mouse model we investigated the antiviral capability of these genes 31 in the control of RSV replication. Over-expression of IFI44 or IFI44L was sufficient to 32 restrict RSV infection at an early time post infection. Knocking out these genes in 33 mammalian airway epithelial cells increased levels of infection. Both genes express 34 antiproliferative factors that have no effect on RSV attachment but reduce RSV 35 replication in a minigenome assay. The loss of Ifi44 was associated with a more 36 severe infection phenotype in vivo. These studies demonstrate a function for IFI44 37 and IFI44L in controlling RSV infection. 38 Importance 39RSV infects all children under two years of age, but only a subset of children get 40 severe disease. We hypothesize that susceptibility to severe RSV necessitating 41 hospitalization in children without pre-defined risk factors is in part mediated at the 42 anti-viral gene level. But there is a large array of anti-viral genes, particularly in the 43 ISG family about which the mechanism is poorly understood. Having observed 44 significantly lower levels of IFI44 and IFI44L gene expression in hospitalized children 45 with a confirmed diagnosis of RSV, we dissected the function of these two genes. 46 Through a range of over-expression and knockout studies we show that the genes 47 are anti-viral and anti-proliferative. This study is important because IFI44 and IFI44L 48 are upregulated after a wide range of viral infections and IFI44L can serve as a 49 diagnostic bio-marker of viral infection.50 94 triphosphate (GTP)-binding region present in either protein. We demonstrate for the 95 first time that the loss of IFI44 expression in a mouse model of infection is associated 96 with more severe RSV disease.97 5 Methods 98 Clinical cohort. IFI44 and IFI44L expression was analysed in a published clinical 99 cohort of febrile infants with either moderate or severe RSV infection [13]. The 100 microarray gene expression dataset (GSE72810) was retrieved from the National 101 Institutes of Health Gene Expression Omnibus database (22) using the GEOquery 102 package (23) in R (24). Normalisation was performed using robust spline 103 normalisation (RSN) from the lumi package (25) followed by a log transformation. 104 Patients with suspected or confirmed bacterial infection were removed (n = 4). 105 Cohort demographics are described in the associated figures. Prior to differential 106 expression probes were removed if the expression was not above 6 in at least 4 107 s...

Internalization of extracellular vesicles from Lactobacillus johnsonii N6.2 elicit an RNA sensory response in human pancreatic cell lines

“…An interesting finding downstream of endosome signalling, was that the genes induced by the L. johnsonii N6.2 EV are associated with exogenous RNA sensing and degradation (OAS, OAS and OASL), the induction of an antiviral cellular immune response (MX and MX) and immune modulation (IFI and IFIL). The induction of these antiviral genes has been shown to control viral infections aiding in both cellular and host survival to viral insults as they are critical in repressing the viral replication and initiating an innate immune response (Busse et al, 2020;Liu et al, 2013;Wickenhagen et al, 2021). This innate immune response may, depending on the context, lead to inflammatory response mediated by cytokines such as interferons and interleukins.…”

GEO Data Sets Analysis On Mechanism of Action of IFNβ-1a Treatment in Multiple Sclerosis

“…IFI44 is made up of 444 amino acids, whereas IFI44L has 452 residues; the two proteins share 45% amino acid identity. Overexpression of IFI44 has been shown to restrict Bunyamwera virus and HIV-1 infection in vitro [31]. Yet this was first identified in the context of hepatitis C virus infection.…”