title: Specific anti-viral effects of RNA interference on replication and expression of hepatitis B virus in mice.
abstract: BACKGROUND
  RNA interference (RNAi) is a powerful tool to silence gene expression post-transcriptionally. Our previous study has demonstrated that small interfering RNAs (siRNAs) have sufficiently inhibited hepatitis B virus (HBV) replication and expression in vitro. In this study we observed the RNAi-mediated inhibitory effects on HBV replication in mice models and accessed the specificity of these effects.
  
  
  METHODS
  A mutant RNAi vector (pSI-C mut) with two base pairs different from the original target gene sequence at the RNAi vector (pSI-C) was constructed according to the method described in this study. A mouse model of acute hepatitis B virus infection was established by injecting naked plasmid pHBV1.3 via the tail vein with acute circulatory overload. pSI-C, pSI-C mut and the irrelevant RNAi control plasmid for green fluorescent protein (GFP) gene, pSIGFP were respectively delivered with pHBV1.3 by tail vein injection method. Six days post injection, enzyme-linked immunosorbent assay (ELISA) assay was used to measure the concentration of HBV surface antigen (HBsAg) in mouse serum, immunohistochemical straining method was used to visualize the expression of HBV core protein (HBcAg) in liver tissues, and the transcriptional level of HBV C mRNA in liver tissues was detected by reverse transcriptase PCR (RT-PCR) analysis.
  
  
  RESULTS
  Injection of pSI-C exerted magnificent and specific inhibitory effects on the replication and expression of HBV in the murine model. After 6-day post-injection (p.i.), the OD values were shown to be 5.07 +/- 1.07 in infecting group and 0.62 +/- 0.59 in pSI-C group. The concentration of HBsAg in pSI-C group was significantly lower than that in infecting group (P < 0.01). Liver intracellular synthesis of viral core protein was sharply reduced to 0.9% +/- 0.1%, compared with 5.4% +/- 1.2% of positive hepatocytes in infecting group (P < 0.01), and the transcriptional level of HBV C mRNA was greatly reduced by 84.7%. However, the irrelevant RNAi control plasmid (pSIGFP), and the pSI-C mut did not show the same robust inhibitory effects as pSI-C.
  
  
  CONCLUSIONS
  pSI-C exert efficient and specific inhibitory effects on HBV replication and expression in mice models.
authors.affiliation: Institute for Viral Hepatitis, Chongqing University of Medical Sciences, Chongqing 400010, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Ai-long
authors.initials: AL
authors.lastname: Huang
authors.forename: Ni
authors.initials: N
authors.lastname: Tang
authors.forename: Bing-qiang
authors.initials: BQ
authors.lastname: Zhang
authors.forename: Nian-fang
authors.initials: NF
authors.lastname: Lu
mesh_terms: D000818:Animals; D006509:Hepatitis B / Q000628:therapy* / Q000821:virology; D006512:Hepatitis B Core Antigens / Q000096:biosynthesis; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics* / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D034622:RNA Interference; D012333:RNA, Messenger / Q000032:analysis; D034741:RNA, Small Interfering / Q000627:therapeutic use; D012367:RNA, Viral / Q000032:analysis; D014779:Virus Replication
chemical_list: D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012367:RNA, Viral