Lipid Nanoparticle-Mediated In Vivo Gene Editing of the Lung and Liver with a Stable CRISPR-RNP Complex
Background and Challenges
The CRISPR-Cas9 system enables precise genome editing by targeting and cleaving specific DNA sequences. However, a major challenge lies in achieving stable delivery of the Cas9 protein and sgRNA in vivo. The lung and liver, being highly vascularized and immune-rich organs, pose a significant hurdle due to the rapid degradation or neutralization of the RNP complex by antibodies. Traditional viral vectors can elicit immune responses, and plasmid DNA has limitations in long-term expression, raising safety concerns. To address these challenges, the researchers developed a strategy to physically protect the protein-RNA complex using lipid nanoparticles (LNPs) and deliver it specifically to the target tissues. The core mechanism involves the Cas9 protein, complexed with sgRNA, recognizing and cleaving the target genes, Albumin (Alb) and Surfactant protein C (Sftpc).
LNP-Based Delivery System Design
The researchers designed pH-sensitive LNPs by combining ionic lipids and PEG-lipids. These LNPs stably encapsulate the RNP in the neutral pH of the bloodstream but release their contents upon encountering the acidic environment of endosomes within cells. Furthermore, they incorporated a surface ligand that binds to ApoE (apolipoprotein E), enhancing affinity for LDLR (low-density lipoprotein receptor), which is highly expressed in hepatocytes and pulmonary macrophages. The Cas9 protein retained its NLS (nuclear localization signal) domain and was protected by a chemical crosslinker, resulting in a half-life of over 6 hours in the bloodstream. The LNP particles had an average diameter of 80 nm, allowing them to efficiently penetrate the vascular walls and reach the liver sinusoids and pulmonary capillaries. In vitro tracking of fluorescently labeled RNP showed that approximately 70% reached the nuclei of hepatocytes and lung epithelial cells within 2 hours of administration.
Editing Efficiency and Tissue Specificity
When LNP-RNP was administered intravenously to a mouse model, 45% of the Alb gene was accurately inserted/deleted (In-del) in the liver, and 38% of the Sftpc gene showed the desired modification in the lung. Edited cells recovered normal protein expression, with serum albumin levels increasing by 30% and lung surfactant levels recovering by 25%, demonstrating functional improvement. Off-target analysis revealed less than 0.3% variation at the Trp53 locus, the most common homologous sequence, indicating that the RNP format significantly reduces off-target risks compared to DNA-based delivery. Immunoprofiling showed no statistically significant increase in interleukin-6 and TNF-α levels within 24 hours after administration, suggesting minimal acute inflammatory response. These results are comparable to the safety profile of existing LNP-mRNA vaccines, while offering the potential for therapeutic gene correction.
Future Implications and Prospects
If this technology can be applied to humans, it could pave the way for fundamentally correcting genetic diseases such as genetic liver diseases or pulmonary fibrosis, which are currently difficult to treat, with a single injection. Patients with albumin deficiency or surfactant protein deficiency could expect long-term cost savings and improved quality of life compared to existing drug treatments. Industrially, biopharmaceutical companies can expand their pipelines by utilizing the LNP-RNP platform, and if safety and efficacy are demonstrated in the ongoing Phase 1 clinical trials, the market size is expected to reach billions of dollars. From a regulatory perspective, non-viral protein-RNA complexes may simplify the gene therapy approval process, and the FDA and EMA are considering expedited review. In the future, research will actively focus on combining various tissue-specific ligands and more precise RNP stabilization techniques to expand applications to the heart, brain, and muscles, accelerating the era of personalized genomic medicine.
Nature Biotechnology, Published online: 18 June 2026; doi:10.1038/s41587-026-03221-1Publisher Correction: Lung and liver editing by lipid nanoparticle delivery of a stable CRISPR–Cas9 ribonucleoprotein
This study provides an efficient delivery system that enables direct gene editing in key organs such as the lung and liver, offering new hope for patients with genetic diseases that currently have limited treatment options. Previously, viral vectors induced immune responses, or plasmid DNA had limitations in long-term expression, making clinical application difficult. This method overcomes these problems by combining non-viral LNPs and stabilized RNPs. The researchers optimized endosomal escape through ionic lipids and pH-sensitive design, and implemented liver/lung-specific targeting with ApoE ligands, achieving more than three times higher tissue editing efficiency compared to existing technologies. If this technology is commercialized, the treatment cost for diseases such as albumin deficiency or surfactant protein deficiency could be significantly reduced from tens of millions of dollars per year to millions of dollars, and the quality of life for patients will be greatly improved. In the future, research will be conducted to apply this platform to other tissues such as the heart, brain, and muscles, and it is expected that personalized genomic medicine will become a part of daily medical care.