Retrovirus inactivated in a porcine model using CRISPR-Cas9

Written by Adam Tarring

Researchers have successfully inactivated porcine endogenous retrovirus in a porcine model using CRISPR-Cas9. This discovery could lead to greater use of porcine tissue and organs for transplantation.

A study lead by researchers from eGenesis (MA, USA) has discovered a method for removing porcine endogenous retroviruses (PERVs) from a porcine model using CRISPR-Cas9. The researchers had previously shown that PERVs could transfer to human cells when cultured together. The ability to remove PERVs could lead to greater use of porcine organs and tissue in transplantation. The study was recently published in Science.

There is currently a shortage of organs and tissue for transplantation, thus using organs and tissue from animals could be a promising field. Porcine organs are particularly compatible with humans, but also contain PERVs which can be transferred to human cells. Gene editing techniques could prove useful for removing PERVs from the pig genome, with researchers showing the effectiveness in immortalized cell lines.

In this study, researchers mapped and characterized the 25 PERV sites that are present in the genome of pig fibroblast cells. Using CRISPR-Cas9 and a number of additional factors, researchers were able to inactivate all of the PERV sites.

When they implanted the embryos into sows, they found that the resulting piglets exhibited no signs of PERVs, with some piglets surviving up to four months after birth. This short survival time shows that more work is needed before this method will be clinically viable way to gain organs and tissue for transplantation.

Sources: Niu D, Wei HJ, Lin L et al. Inactivation of porcine endogenous retrovirus in pigs using CRISPR-Cas9. Science. doi: 10.1126/science.aan4187 (2017) (Epub ahead of print);…