LIMA1 Gene Knockout by CRISPR/Cas9 System Using Lentiviruses as an in Vitro Model for Reducing Cholesterol Absorption

Background: Cardiovascular diseases, with an estimated 18.6 million deaths per year, are the leading cause of death worldwide. One of the major risk factors is elevated blood low-density lipoprotein cholesterol (LDL-C) secondary to multiple environmental and genetic factors. Genes involved in LDL-C metabolism are the targets of the most common treatment options. Advanced molecular techniques could pave the way for identifying novel targets in dyslipidemia therapies. The LIM domain and actin-binding 1 (LIMA1) gene binds to the NPC1L1 protein and facilitates its more efficient recycling to the plasma membrane. Inhibition of LIMA1 could disrupt cellular cholesterol hemostasis with a probable decrease in blood LDL-C levels.

Objectives: The present study was designed to knock out exon 2 of the LIMA1 gene using lentiviruses as an in vitro model for reducing cholesterol absorption.

Methods: A CRISPR/Cas9 system with dual guide RNAs (gRNAs) was designed to completely excise exon 2 of LIMA1. Two gRNAs (gRNA1 and gRNA2) were cloned in the LentiCRISPR v2 vector. LentiCRISPR viruses were produced in the HEK293T cell line to encode the CRISPR/Cas9 complex structure. HepG2 cell lines were transduced with two different LentiCRISPR viruses simultaneously.

Results: Exon 2 deletion was detected by PCR, gel electrophoresis, and subsequent Sanger sequencing of the PCR product. Exon 2 deletion caused a frameshift mutation, and the subsequent production of nonfunctional transcripts led to gene knockout. The dual gRNA CRISPR/Cas9 system could be used in gene editing setups.

Conclusions: The in vitro knockout model of LIMA1 could be considered as preliminary work to study the role and mechanism of action of the LIMA1 protein, along with its potential as a target for hypercholesterolemia therapy.