LPA Disruption With AAV-CRISPR Potently Lowers Plasma Apo(a) in Transgenic Mouse Model: A Proof-of-Concept Study

Authors

Alexandria M Doerfler
So Hyun Park
Julia M Assini
Amer Youssef
Lavanya Saxena
Adam B Yaseen
Marco De Giorgi
Marcel Chuecos
Ayrea E Hurley
Ang Li
Santica M Marcovina
Gang Bao
Michael B Boffa
Marlys L Koschinsky
William R Lagor

Publication Date

12-8-2022

Journal

Molecular Therapy Methods & Clinical Development

DOI

10.1016/j.omtm.2022.10.009

PMID

36381302

PMCID

PMC9630778

PubMedCentral® Posted Date

10-13-2022

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

lipoprotein(a), LPA, apolipoprotein(a), liver, gene therapy, adeno-associated virus, somatic genome editing, CRISPR-Cas9, AAV-CRISPR, atherosclerosis

Abstract

Lipoprotein(a) (Lp(a)) represents a unique subclass of circulating lipoprotein particles and consists of an apolipoprotein(a) (apo(a)) molecule covalently bound to apolipoprotein B-100. The metabolism of Lp(a) particles is distinct from that of low-density lipoprotein (LDL) cholesterol, and currently approved lipid-lowering drugs do not provide substantial reductions in Lp(a), a causal risk factor for cardiovascular disease. Somatic genome editing has the potential to be a one-time therapy for individuals with extremely high Lp(a). We generated an LPA transgenic mouse model expressing apo(a) of physiologically relevant size. Adeno-associated virus (AAV) vector delivery of CRISPR-Cas9 was used to disrupt the LPA transgene in the liver. AAV-CRISPR nearly completely eliminated apo(a) from the circulation within a week. We performed genome-wide off-target assays to determine the specificity of CRISPR-Cas9 editing within the context of the human genome. Interestingly, we identified intrachromosomal rearrangements within the LPA cDNA in the transgenic mice as well as in the LPA gene in HEK293T cells, due to the repetitive sequences within LPA itself and neighboring pseudogenes. This proof-of-concept study establishes the feasibility of using CRISPR-Cas9 to disrupt LPA in vivo, and highlights the importance of examining the diverse consequences of CRISPR cutting within repetitive loci and in the genome globally.

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