Long-term effects of PERV-specific RNA interference in transgenic pigs

Area of Science:

• Xenotransplantation research
• Molecular biology
• Genetics

Background:

• Porcine endogenous retroviruses (PERVs) pose a risk in xenotransplantation due to their ability to infect human cells.
• Transgenic pigs were engineered to express a PERV-specific small hairpin RNA (shRNA) to reduce viral load via RNA interference.
• The long-term efficacy of this RNA interference in suppressing PERV expression needed further investigation.

Purpose of the Study:

• To evaluate the long-term effectiveness and duration of RNA interference in transgenic pigs engineered to suppress porcine endogenous retroviruses (PERVs).
• To assess the sustained expression of PERV-specific shRNA and its impact on PERV replication over a three-year period.

Main Methods:

• Long-term monitoring of PERV-specific shRNA expression and PERV inhibition in fibroblasts and PBMCs from transgenic pigs over three years.
• Utilized a novel real-time PCR for quantifying shRNA expression and a PERV-specific real-time PCR for measuring PERV levels.
• Analyzed shRNA and PERV expression in various organs after animal sacrifice.

Main Results:

• Consistent expression of PERV-specific shRNA and reporter gene (GFP) was observed in transgenic pigs throughout the three-year study period.
• Significant and sustained reduction in PERV expression was achieved in all tested tissues compared to control animals.
• PERV and shRNA expression levels varied across different organs, with highest PERV levels in spleen and lungs, and lowest in liver and heart.

Conclusions:

• Transgenic pigs demonstrated sustained RNA interference, effectively maintaining long-term suppression of PERV expression.
• This suggests that xenotransplantation using these engineered pigs could offer enhanced viral safety due to prolonged PERV suppression.