Permanent Alteration of PCSK9 With In Vivo CRISPR-Cas9 Genome Editing
Rationale: Individuals with naturally occurring loss-of-function PCSK9 mutations experience reduced blood low-density lipoprotein cholesterol (LDL-C) levels and protection against cardiovascular disease.
Objective: The goal of this study was to assess whether genome editing using a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system can efficiently introduce loss-of-function mutations into the endogenous PCSK9 gene in vivo.
Methods and Results: We used adenovirus to express Cas9 and a CRISPR guide RNA targeting Pcsk9 in mouse liver, where the gene is specifically expressed. We found that within three to four days of administration of the virus, the mutagenesis rate of Pcsk9 in the liver was as high as >50%. This resulted in decreased plasma PCSK9 levels, increased hepatic LDL receptor levels, and decreased plasma cholesterol levels (by 35%-40%) in the blood. No off-target mutagenesis was detected in 10 selected sites.
Conclusions: Genome editing with the CRISPR-Cas9 system disrupts the Pcsk9 gene in vivo with high efficiency and reduces blood cholesterol levels in mice. This approach may have therapeutic potential for the prevention of cardiovascular disease in humans.
- Received May 8, 2014.
- Revision received June 6, 2014.
- Accepted June 9, 2014.