Lipid nanoparticle delivery of TALEN mRNA targeting LPA causes gene disruption and plasma lipoprotein(a) reduction in transgenic mice
Daniel A. Garcia, Abigail F. Pierre, Linda Quirino, Grishma Acharya, Vasudevan Ayyappan, Yihua Pei, Emily Chung, Jason Y.H. Chang, Samuel S. Lee, Michael Endow, Kristen Kuakini, Michael Bresnahan, Maria Chumpitaz, Kumar Rajappan, Suezanne E. Parker, Padmanabh Chivukula, Stefen A. Boehme, Ramón Dı́az-Trelles
Abstract
Lipoprotein(a), or Lp(a), is encoded by the LPA gene and is a causal genetic risk factor for cardiovascular disease. Individuals with high Lp(a) are at risk for cardiovascular morbidity and are refractory to standard lipid-lowering agents. Lp(a)-lowering therapies currently in clinical development require repetitive dosing, while a gene editing approach presents an opportunity for a single-dose treatment. In this study, mRNAs encoding transcription activator-like effector nucleases (TALENs) were designed to target human LPA for gene disruption and permanent Lp(a) reduction. TALEN mRNAs were screened in vitro and found to cause on-target gene editing and target protein reduction with minimal off-target editing. TALEN mRNAs were then encapsulated with LUNAR, a proprietary lipid nanoparticle (LNP), and administered to transgenic mice that expressed a human LPA transgene. A single dose of TALEN mRNA-LNPs reduced plasma Lp(a) levels in mice by over 80%, which was sustained for at least 5 weeks. Moreover, both standard and long-read next-generation sequencing confirmed the presence of gene-inactivating deletions at LPA transgene loci. Overall, this study serves as a proof-of-concept for using TALEN-mediated gene editing to disrupt LPA in vivo, paving the way for the development of a feasible gene editing therapy for patients with high Lp(a).