Inherited cardiovascular diseases (CVDs) represent a significant health concern, contributing to sudden cardiac deaths and imposing a substantial burden on healthcare systems across Europe. These conditions, predominantly encompassing cardiomyopathies and channelopathies, affect approximately 1 in every 200 adults. While a few medications exist to slow disease progression, no cure currently exists for inherited CVDs. These diseases primarily stem from individual point mutations scattered throughout various genes, with multiple pathological mutations often identified within a single gene.
Over the past two decades, significant advancements have occurred in genome editing, offering powerful tools to correct disease-causing mutations at the DNA level, particularly for translational research. Among these tools, clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 genome editing has emerged as a simple and cost-effective approach for potentially treating previously untreatable conditions, such as inherited CVDs. The recent development of base editing technology has further enhanced the precision of editing, allowing for the correction of point mutations without DNA cleavage. Base editors can induce specific base pair transitions within a defined editing window, guided by a single guide RNA (sgRNA). Despite the growing recognition of base editing’s potential in the field of cardiology, its efficacy in rectifying mutations causing cardiomyopathies and the promising therapeutic benefits remain underexplored. This is partially due to the absence of a suitable in vitro model of mature human cardiomyocytes that accurately replicates the intricate cellular makeup of the human heart.
Recent advancements in tissue engineering, coupled with a deeper understanding of the interactions between noncardiomyocytes and cardiomyocytes, have led to the development of three-dimensional (3D) human cardiac organoids (hCOs) derived from human induced pluripotent stem cells (hiPSCs). hCOs represent a cutting-edge in vitro model that closely mimics the human heart’s in vivo environment, overcoming previous limitations related to cardiomyocyte immaturity and the inability to replicate adult heart characteristics. These hCOs are constructed as 3D scaffold-free cardiac microtissues, composed of three key cell types: hiPSC-derived cardiomyocytes, cardiac fibroblasts, and cardiac endothelial cells. This approach offers a straightforward and versatile platform for modeling inherited CVDs.
The “Precise Genome Editing to Correct Cardiomyopathies in Human Cardiac Organoids” (Edit-hCOs) project was initiated with the aim of establishing an innovative research avenue for developing genome editing-based therapies to address inherited CVDs. The overarching objective of the project was to integrate the precision genome editing capabilities of CRISPR-Cas9 base editing with 3D hCOs, creating a platform to showcase the potential applications of base editing in an advanced in vitro model that faithfully recapitulates the complex cellular landscape of the human heart. Leveraging base editing within hCOs allows for the rapid and robust assessment of the effectiveness, delivery systems, and safety profiles of genome editing components. This represents a crucial pre-clinical step toward the therapeutic genome editing of CVDs.
The project’s objectives were initially planned to be completed within a 2-year timeframe. However, after the first year, the Fellow received a career advancement opportunity, accepting a position as a Professor of Genetics at the University of Bologna. Despite this change, the project’s major objectives were successfully achieved within the initial 12 months, demonstrating that base editing could be effectively used to introduce genetic disease-causing mutations in cardiac organoids and, more importantly, to correct genetic mutations identified in patients affected by CVDs. Future collaboration between the Fellow and Supervisor will ensure the completion of the functional characterization of these cardiac organoids.
