Base and Prime Editing Without Double-Strand Breaks Expand Treatment Horizons for Vascular Smooth Muscle Genetic Diseases
Background
Smooth muscle cells (SMCs) are key tissue elements constituting the walls of major human organs, including the cardiovascular, respiratory, digestive, and urogenital systems, responsible for organ contraction and lumen pressure regulation. If SMCs in the vascular wall lose function or proliferate abnormally, it leads directly to severe diseases such as aneurysms, early atherosclerosis, and hereditary cerebrovascular diseases. Until now, research into treating smooth muscle diseases has mostly been limited to symptomatic drug therapies to slow disease progression or surgical stent insertions. This is because it has been difficult to fundamentally eliminate the causes of congenital vasculopathy caused by single nucleotide abnormalities in specific genes.
Existing 1st and 2nd generation CRISPR gene-editing technologies induced DNA double-strand breaks (DSBs) when cutting target genes. During the cell's natural repair process, random insertions or deletions (indels) occur, and risks of large-scale chromosomal rearrangements or carcinogenesis persist, making direct application to vascular wall cells—which require regulated proliferation—too risky. Furthermore, vascular smooth muscle cells present a physical barrier to the precise delivery of gene-editing materials because they are located beneath the vascular endothelial cells.
Key Findings
The researchers pointed out that smooth muscle disease research has reached a rapid turning point as genome editing technology has evolved into base editing (BE) and prime editing (PE), which do not cause double-strand breaks. Base editing precisely replaces single nucleotides, while prime editing uses reverse transcriptase to directly write in desired sequences. Both methods provide a means to revert pathogenic single-nucleotide mutations while drastically reducing the risk of chromosomal damage.
The academic community has been proving disease mechanisms by applying these precision editing tools to patient-derived primary cultured cells and smooth muscle cell models differentiated from induced pluripotent stem cells (iPSCs). This has enabled real-time tracking at the cellular level of the processes where specific gene mutations induce vascular contractile protein deficiency or cell death. In particular, in experimental systems linking patient iPSC-derived SMCs with 3D vascular organoids, it has been repeatedly confirmed that when patient-specific mutations are reverted to normal sequences, cell contractility and elasticity recover to normal ranges.
In vivo correction strategies using preclinical animal models are also becoming more concrete. The researchers compiled findings demonstrating the suppression of abnormal vascular wall thickening and dissection risks by injecting targeted editing enzymes into the blood vessels of mouse models carrying pathogenic mutations. They demonstrated that precise substitution, which reverts pathogenic gene sequences to normal nucleotides, functions within vascular tissue, moving beyond the conventional knockout approach that merely induces loss of gene function.
Significance and Outlook
This achievement presents the possibility of fundamentally correcting rare, incurable vascular diseases caused by vascular smooth muscle abnormalities, such as hereditary aortic aneurysm, Marfan syndrome, and Ehlers-Danlos syndrome. It has opened a therapeutic platform that can prevent the structural collapse of blood vessels with a one-time gene correction for patients born with congenital defects.
However, engineering challenges remain to be overcome for clinical application. The development of highly efficient target delivery vehicles capable of transporting editing tools deep into the smooth muscle layer of the vascular wall during administration is cited as the top priority. Surface modification must precede the use of adeno-associated virus (AAV) or lipid nanoparticles (LNP) exposed to the systemic circulation so that they bind specifically to smooth muscle cells without accumulating in the liver. Technologies to suppress off-target mutations caused by the long-term in vivo expression of editing enzymes and immune responses to bacteria-derived Cas proteins are also essential. As the evolution of delivery platforms and organoid-based safety verification converge, the clinical entry of smooth muscle gene editing technology is expected to accelerate.
Smooth muscle cells (SMCs) are essential for the normal function of the cardiovascular, respiratory, gastrointestinal, and urogenital systems, and SMC dysfunction contributes to a wide range of genetic and acquired diseases. CRISPR-based genome editing provides new approaches for studying SMC biology and developing therapies for smooth muscle disorders. In particular, base editing and prime editing enable precise nucleotide changes without introducing DNA double-strand breaks. In this review, we summarize recent applications of CRISPR technologies in smooth muscle biology, with a primary focus on vascular diseases. We discuss how CRISPR-engineered primary cells, induced pluripotent stem cell (iPSC)-derived SMCs, and animal models have been used to investigate disease mechanisms and validate pathogenic variants. We further review therapeutic genome editing strategies for correcting disease-causing variants in patient-derived iPSC-SMCs, vascular organoids, and preclinical animal models. Finally, we discuss major challenges for clinical translation, including efficient and SMC-specific delivery, immunogenicity, editing precision, off-target effects, and long-term safety. Continued advances in genome-editing technologies, delivery platforms, and human disease models may expand the application of these approaches to smooth muscle disorders.
This research provides a concrete blueprint for developing next-generation cell and gene therapies (CGT) targeting the patient group with thoracic aortic aneurysms based on ACTA2 and MYH11 mutations, for whom no appropriate curative treatment existed. For patients who previously had to rely on lifelong blood pressure-lowering drugs or wait for high-risk artificial vessel replacement to prevent vascular rupture immediately after diagnosis, gene-editing drugs that correct the causative genes could emerge as an alternative.
From an industrial perspective, it acts as a driver to promote the development of smooth muscle-targeted lipid nanoparticles (LNPs) and virus-like particle (VLP)-based fusion protein delivery systems. As the in vivo gene editing market, which was focused on liver-targeted diseases, expands into the vascular disease domain, competition for securing intellectual property for new platform technologies combining vascular smooth muscle-specific promoters and ligands is expected to intensify. Patient-specific iPSC-derived vascular organoid screening systems possess the potential to significantly reduce clinical development costs and duration by rapidly verifying the toxicity and efficacy of drug candidates at the preclinical stage.