Elimination of CaMKIIδ Autophosphorylation by CRISPR-Cas9 Base Editing Improves Survival and Cardiac Function in...

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Gene Editing Technologies

Background:

• Cardiovascular diseases are a leading cause of death globally, necessitating novel therapeutic strategies.
• Overactivation of the cardiac enzyme Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) is a key factor in various heart disorders.

Purpose of the Study:

• To develop a gene-editing therapy for heart failure by targeting the autophosphorylation site of CaMKIIδ.
• To assess the efficacy and safety of CRISPR-Cas9 adenine base editing in a mouse model of heart failure and in human cells.

Main Methods:

• CRISPR-Cas9 adenine base editing was used to create a phospho-resistant CaMKIIδ mutation in mice.
• Mice underwent transverse aortic constriction to induce heart failure; cardiac function, gene expression, apoptosis, and fibrosis were evaluated.
• Human induced pluripotent stem cells were edited to target the homologous CaMKIIδ site, with specificity assessed via deep amplicon sequencing.

Main Results:

• Gene-edited mice exhibited significantly reduced mortality (11% vs. 65%) and improved cardiac function post-heart failure induction compared to wild-type mice.
• CaMKIIδ-edited mice were protected against heart failure-induced changes in gene expression, apoptosis, and fibrosis.
• Edited human cells and cardiomyocytes showed protection against Ca2+ dysregulation and arrhythmias under stress, with high editing specificity for CaMKIIδ.

Conclusions:

• Ablating CaMKIIδ autophosphorylation via adenine base editing offers a potential therapeutic strategy for human cardiac diseases.
• The high specificity of the gene editing tool for CaMKIIδ is a critical safety feature for potential clinical translation.