Effective inhibition of hepatitis E virus replication in A549 cells and piglets by RNA interference (RNAi) targeting RNA-dependent RNA polymerase

Abstract

RNA interference (RNAi) is a natural mechanism for suppressing or silencing expression of aberrant or foreign genes. It is a powerful antiviral strategy that has been widely employed to protect hosts from viral infection. Hepatitis E (HE) is an acute fulminant hepatitis in adults that has particularly high mortality in pregnant women. At this point in time, there is no vaccine or antiviral treatment that is effective against the infectious agent, HEV. The nonstructural polyprotein region possesses an RNA-dependent RNA polymerase (RdRp) that is responsible for the replication of the viral RNA genome. RdRp is therefore regarded as one of the most attractive candidates for RNA interference (RNAi). In the present study, the high efficiency and specificity of siRNA were evaluated by Real-Time quantitative PCR and Western blot assays. Protective effects against HEV infection were achieved in A549 cells and in piglets. In piglets treated with a shRNA-RdRp-1 expression plasmid prior to HEV inoculation, HEV antigens were significantly reduced in the liver, spleen, and kidneys, and the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBIL) were clearly decreased. These results suggested that RNAi is a potentially effective antiviral strategy against HEV replication and infection.

A review on current status of antiviral siRNA

“…Hepeviridae mainly includes hepatitis E virus, a key source of water‐borne hepatitis in adults that has particularly high mortality in pregnant women. Short interfering RNAs developed against the helicase and replicase genes of hepatitis E virus were found to be effective in inhibiting virus replication in A549 as well as HepG2 cells …”

Immunopathogenesis of Hepatitis E Virus Infection

“…Various animal species (pigs, rodents, rabbits) were found to be naturally infected with HEV genotypes 3 and 4 or susceptible to both animal-derived and human-derived HEV genotypes 3 and 4. [55][56][57][58][59][60] The variety of patterns of experimental HEV infection in nonhuman primates, especially in chimpanzees 54 resembles clinically overt or subclinical HEV infection in humans. The extent of the virologic, immunologic, and pathologic sequelae of HEV infection observed in experimentally infected primates may be related to the size of the infectious dose as well as host susceptibility to HEV.…”

Successful infection of BALB/c mice by a swine hepatitis E virus clone constructed with reverse genetics

“…Replication of HEV in multiple tissues, including liver, spleen, kidney and colon, has been reported in both pigs and nude mice when inoculated with HEV [21, 26]. In order to further analyze the replication of HEV in different tissues, HEV genome RNA and capsid protein (ORF2) were analyzed by RT-nPCR, qRT-PCR and Western blotting, respectively.…”