Viral Sequences Are Repurposed for Controlling Antiviral Responses as Non-Retroviral Endogenous Viral Elements

Eukaryotic genomes contain numerous copies of endogenous viral elements (EVEs), most of which are considered endogenous retrovirus (ERV) sequences. Over the past decade, non-retroviral endogenous viral elements (nrEVEs) derived from ancient RNA viruses have been discovered. Several functions have been proposed for these elements, including antiviral defense. This review summarizes the current understanding of nrEVEs derived from RNA viruses, particularly endogenous bornavirus-like elements (EBLs) and endogenous filovirus-like elements (EFLs). EBLs are one of the most extensively studied nrEVEs. The EBL derived from bornavirus nucleoprotein (EBLN) is thought to function as a non-coding RNA or protein that regulates host gene expression or inhibits virus propagation. Ebolavirus and marburgvirus, which are filoviruses, induce severe hemorrhagic fever in humans and nonhuman primates. Although the ecology of filoviruses remains unclear, bats are believed to be potential reservoirs. Based on the knowledge from EBLs, it is postulated that EFLs in the bat genome help to maintain the balance between filovirus infection and the bat’s defense system, which may partially explain why bats act as potential reservoirs. Further research into the functions of nrEVEs could reveal novel antiviral systems and inspire novel antiviral approaches

11Rを用いた新しいタンパク質導入法―脳血管障害を治療するための効果的な新しい薬物伝達システム―

BACKGROUND AND PURPOSE: A motif of 11 consecutive arginines (11R) is reported to be one of the most effective protein transduction domains for introducing proteins into the cell membrane. We therefore examined the transduction efficiency of 11R in cerebral arteries. METHODS: Basilar arteries (BAs) obtained from rats were incubated with either 11R-enhanced green fluorescent protein (11R-EGFP) or EGFP without 11R. After incubation, expression of 11R-EGFP or EGFP in BA serial sections was observed by fluorescence microscope. In an additional in vivo experiment, 11R-EGFP or EGFP was injected into the cisterna magna with or without subarachnoid hemorrhage. The 11R-EGFP or EGFP was injected just after the autologous blood injection, and then the expression of 11R-EGFP or EGFP in BA sections was also observed by fluorescence microscope. RESULTS: The 11R-EGFP signal was much stronger than that of EGFP in all layers of the rat BA, in both in vivo and ex vivo experiments. Moreover, the 11R-EGFP was transduced into the BA immediately (2 hours after the injection). Interestingly, 11R-fused fluorescent protein was transduced especially into the tunica media of the BA. CONCLUSIONS: The 11R-fused fluorescent protein effectively penetrates into all layers of the rat BA, especially into the tunica media. This is the first study to our knowledge to demonstrate the successful transduction of a protein transduction domain fused protein into the cerebral arteries

Suppression of Borna Disease Virus Replication during Its Persistent Infection Using the CRISPR/Cas13b System

Borna disease virus (BoDV-1) is a bornavirus that infects the central nervous systems of various animal species, including humans, and causes fatal encephalitis. BoDV-1 also establishes persistent infection in neuronal cells and causes neurobehavioral abnormalities. Once neuronal cells or normal neural networks are lost by BoDV-1 infection, it is difficult to regenerate damaged neural networks. Therefore, the development of efficient anti-BoDV-1 treatments is important to improve the outcomes of the infection. Recently, one of the clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) systems, CRISPR/Cas13, has been utilized as antiviral tools. However, it is still unrevealed whether the CRISPR/Cas13 system can suppress RNA viruses in persistently infected cells. In this study, we addressed this question using persistently BoDV-1-infected cells. The CRISPR/Cas13 system targeting viral mRNAs efficiently decreased the levels of target viral mRNAs and genomic RNA (gRNA) in persistently infected cells. Furthermore, the CRISPR/Cas13 system targeting viral mRNAs also suppressed BoDV-1 infection if the system was introduced prior to the infection. Collectively, we demonstrated that the CRISPR/Cas13 system can suppress BoDV-1 in both acute and persistent infections. Our findings will open the avenue to treat prolonged infection with RNA viruses using the CRISPR/Cas13 system

Protein Transduction Method for Cerebrovascular Disorders

Many studies have shown that a motif of 11 consecutive arginines (11R) is one of the most effective protein transduction domains (PTD) for introducing proteins into the cell membrane. By conjugating this &#34;11R&#34;, all sorts of proteins can effectively and harmlessly be transferred into any kind of cell. We therefore examined the transduction efficiency of 11R in cerebral arteries and obtained results showing that 11R fused enhanced green fluorescent protein (11R-EGFP) immediately and effectively penetrated all layers of the rat basilar artery (BA), especially the tunica media. This method provides a revolutionary approach to cerebral arteries and ours is the first study to demonstrate the successful transductionof a PTD fused protein into the cerebral arteries. In this review, we present an outline of our studies and other key studies related to cerebral vasospasm and 11R, problems to be overcome, and predictions regarding future use of the 11R protein transduction method for cerebral vasospasm (CV).</p