In vivo base editing of Angptl3 via lipid nanoparticles to treat cardiovascular disease.

Cardiovascular disease (CVD) is the leading cause of death globally and is exacerbated by elevated blood levels of low-density lipoprotein cholesterol (LDL-C) and triglycerides (TGs). Existing approaches for decreasing blood lipid levels rely on daily medications, leading to poor patient adherence. Gene therapy represents a promising "one and done" strategy to durably reduce blood lipid levels. ANGPTL3 has emerged as a potential target for gene therapy, as naturally occurring loss-of-function variants are cardioprotective. Here, we use lipid nanoparticles to package and deliver CRISPR adenine base editors (ABEs), which enable gene knockout without requiring potentially harmful DNA double-strand breaks. We package ABE mRNA and a synthetic guide RNA targeted to disrupt an important splice site in Angptl3, which we administered to mice intravenously. We achieved over 60% base editing in the liver and durable reductions in serum ANGPTL3, LDL-C, and TGs for at least 100 days. Notably, blood lipid levels remained low when mice were challenged with a high-fat high-cholesterol diet up to 191 days after therapy. These results provide a foundation for a potential one-and-done treatment for CVD.