Vol.:(0123456789) 1 3 Archives of Virology https://doi.org/10.1007/s00705-017-3666-9 ORIGINAL ARTICLE Vivo‑morpholino oligomers strongly inhibit dengue virus replication and production Patta Phumesin 1,2  · Mutita Junking 1  · Aussara Panya 1  · Petlada Yongpitakwattana 1  · Sansanee Noisakran 3  · Thawornchai Limjindaporn 4  · Pa‑thai Yenchitsomanus 1 Received: 2 June 2017 / Accepted: 16 November 2017 © Springer-Verlag GmbH Austria, part of Springer Nature 2017 Abstract Dengue virus (DENV) infection is a worldwide public health problem, which can cause severe dengue hemorrhagic fever (DHF) and life-threatening dengue shock syndrome (DSS). There are currently no anti-DENV drugs available, and there has been an intensive search for efective anti-DENV agents that can inhibit all four DENV serotypes. In this study, we tested whether vivo-morpholino oligomers (vivo-MOs), whose efect on DENV infection has not previously been studied, can inhibit DENV infection. Vivo-MOs were designed to target the top of 3’ stem-loop (3’ SL) in the 3’ UTR of the DENV genome and tested for inhibition of DENV infection in monkey kidney epithelial (Vero) cells and human lung epithelial carcinoma (A549) cells. The results showed that vivo-MOs could bind to a DENV RNA sequence and markedly reduce DENV-RNA, protein, and virus production in infected Vero and A549 cells. Vivo-MOs at a concentration of 4 µM could inhibit DENV production by more than 10 4 -fold when compared to that of an untreated control. In addition, vivo-MOs also inhibited DENV production in U937 cells and primary human monocytes. Therefore, vivo-MOs targeting to the 3’ SL in the 3’ UTR of DENV genomes are efective and have the potential to be developed as anti-DENV agents. Introduction Dengue hemorrhagic fever (DHF) is a mosquito-borne viral disease that has spread across tropical and subtropical areas. Each year, approximately 390 million people are at risk for dengue virus (DENV) infection [1]. A licensed vaccine for DENV is now available, but it has not been fully efective [2, 22]. The vaccine has shown a 59% decrease in its efciency one year after immunization [5]. Moreover, there are no anti- DENV drugs for treatment of DENV disease in clinical use. Many compounds targeting diferent steps of the DENV replication cycle have been evaluated in clinical trials [7]. Nevertheless, none of them have resulted in a signifcant antiviral efect or improvement of clinical outcomes [12, 29]. Diferent types of inhibitors, including chemical compounds [10, 20, 27], nucleoside analogs [33], antibodies [19, 23], peptides [17, 18], small interfering RNAs (siRNAs) [26], short hairpin RNAs (shRNAs), and microRNAs (miRNAs) [32] have exhibited anti-DENV activity in in vitro studies, but their efcacy needs to be tested in clinical trials. The use of siRNAs or shRNAs as anti-DENV agents may not be efective, because it has recently been shown that non-struc- tural protein 4B (NS4B) of DENV can suppress the function of RNA interference (RNAi) machinery, resulting in inhi- bition of the siRNA function [6]. Other molecules such as antisense oligonucleotide (ASO) inhibitors that bind directly to DENV RNA should be more efective for DENV inhibi- tion. Phosphorothioate oligomers are ASO inhibitors that have been approved by the Food and Drug Administration Handling Editor: Zhongjie Shi. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00705-017-3666-9) contains supplementary material, which is available to authorized users. * Pa-thai Yenchitsomanus pathai.yen@mahidol.ac.th; ptyench@gmail.com 1 Siriraj Center of Research Excellence for Molecular Medicine (SiCORE-MM), Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand 2 Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand 3 Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand 4 Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand