Silencing herpes simplex virus type 1 capsid protein encoding genes by siRNA: a promising antiviral therapeutic approach

PLoS One. 2014 May 2;9(5):e96623. doi: 10.1371/journal.pone.0096623. eCollection 2014.

Abstract

Herpes simplex virus type 1 (HSV-1), a member of the herpesviridae, causes a variety of human viral diseases globally. Although a series of antiviral drugs are available for the treatment of infection and suppression of dissemination, HSV-1 remains highly prevalent worldwide. Therefore, the development of novel antiviral agents with different mechanisms of action is a matter of extreme urgency. During the proliferation of HSV-1, capsid assembly is essential for viral growth, and it is highly conserved in all HSV-1 strains. In this study, small interfering RNAs (siRNAs) against the HSV-1 capsid protein were screened to explore the influence of silencing capsid expression on the replication of HSV-1. We designed and chemically synthesized siRNAs for the capsid gene and assessed their inhibitory effects on the expression of target mRNA and the total intracellular viral genome loads by quantitative real-time PCR, as well as on the replication of HSV-1 via plaque reduction assays and electron microscopy. Our results showed that siRNA was an effective approach to inhibit the expression of capsid protein encoding genes including UL18, UL19, UL26, UL26.5, UL35 and UL38 in vitro. Interference of capsid proteins VP23 (UL18) and VP5 (UL19) individually or jointly greatly affected the replication of clinically isolated acyclovir-resistant HSV-1 as well as HSV-1/F and HSV-2/333. Plaque numbers and intracellular virions were significantly reduced by simultaneous knockdown of UL18 and UL19. The total intracellular viral genome loads were also significantly decreased in the UL18 and UL19 knockdown groups compared with the viral control. In conclusion, interfering with UL18 and UL19 gene expression could inhibit HSV-1 replication efficiently in vitro. Our research offers new targets for an RNA interference-based therapeutic strategy against HSV-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsid Proteins / genetics*
  • Chlorocebus aethiops
  • Gene Expression Regulation, Viral
  • Genetic Therapy
  • Herpes Simplex / therapy
  • Herpes Simplex / virology*
  • Herpesvirus 1, Human / genetics
  • Herpesvirus 1, Human / physiology*
  • Humans
  • RNA Interference*
  • RNA, Small Interfering / administration & dosage
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology*
  • Transfection
  • Vero Cells
  • Virus Replication*

Substances

  • Capsid Proteins
  • RNA, Small Interfering

Grants and funding

This work was supported by the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (SQ2011SF12B02099), the National High Technology Research and Development Program of China (863 Program)(2012AA02A405), the National Natural Science Foundation of China (81274170), the marine fishery science and technology promotion programme of Guangdong province (A201301C06), and the Major Platform Project Funds of Administration of Ocean and Fisheries of Guangdong province (GD2012-D01-002). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.