Clonogenic Hepatocytes Drive Liver Growth and Enhance Pediatric Gene Therapy Efficacy
Key Insights
Researchers at San Raffaele Telethon Institute for Gene Therapy (search) discovered that only 15-20% of hepatocytes (search) in newborn mice, called clonogenic hepatocytes (search), generate over 90% of adult liver mass.
Gene editing by homology-directed repair is significantly enriched within clonogenic hepatocytes (search), resulting in expanded gene-edited liver areas during organ growth.
The study reveals that liver maturation reduces gene therapy efficiency in certain zones due to increased proteasome activity, but this barrier can be overcome with proteasome inhibitors.
A groundbreaking study published in the Journal of Hepatology reveals that a small subset of liver cells in newborns holds the key to more effective pediatric gene therapies. Researchers from the San Raffaele Telethon Institute for Gene Therapy (search) (SR-Tiget) have identified that only 15-20% of hepatocytes (search) in newborn mice—termed clonogenic hepatocytes (search)—are responsible for generating over 90% of the adult liver mass.
These findings have major implications for treating inherited liver diseases (search) in children through gene therapy approaches, offering new insights into timing and targeting strategies that could dramatically improve treatment outcomes.
Advanced Technologies Reveal Cellular Architecture
The research team employed cutting-edge methodologies including single-cell and spatial transcriptomics, clonal tracing, and mathematical modeling to analyze hepatocyte proliferation and maturation after birth. This comprehensive approach enabled identification of both the clonogenic cells and the molecular signals regulating their activity.
"Using spatial transcriptomics, we captured the precise localization and transcriptional identity of hepatocytes (search) during postnatal liver growth," explains Dr. Michela Milani, co-first author of the study. "It gave us an unprecedented view into how different hepatocyte subsets proliferate and mature."
Gene Therapy Efficiency Varies by Cell Type and Timing
The study revealed critical differences in how various gene delivery methods interact with hepatocytes (search). Gene editing by homology-directed repair (HDR) showed significant enrichment within clonogenic hepatocytes (search), resulting in expansion of the gene-edited liver area as the organ grows.
In contrast, lentiviral vectors (search) distribute more evenly across hepatocyte populations, but their efficiency depends on cellular maturation state and liver location. The emergence of peri-central (PC) identity after weaning particularly reduces vector uptake due to elevated proteasome activity.
"Knowing that the liver becomes less permissive to gene transfer in certain zones as it matures helps us refine not just what cells to target, but also when to treat," says Dr. Francesco Starinieri, co-first author.
Importantly, the researchers demonstrated that pre-treatment with proteasome inhibitors could restore lentiviral transduction in adult hepatocytes (search), suggesting this maturation barrier can be pharmacologically overcome to improve gene delivery in mature livers.
Specialized Tissue Niches Support Growth
Another significant discovery involves a specialized instructive tissue niche in neonatal livers where clonogenic hepatocytes (search) are found in close proximity to hematopoietic progenitor cells (search). This spatial co-localization suggests shared growth signal pools and opens new possibilities for regenerative medicine applications.
Clinical Implications for Pediatric Treatment
"This study extends our understanding of how the liver grows and matures and how we can intervene early in life to durably correct genetic diseases," says Dr. Alessio Cantore, senior and corresponding author. "By identifying the specific hepatocytes (search) that fuel liver growth—and how they respond to gene delivery—we can now rationally design more effective and lasting therapies for children."
The research provides a clearer roadmap for developing precise and durable pediatric gene therapies by understanding which cells drive organ expansion and their responses to gene delivery methods. This knowledge could significantly benefit children suffering from inherited liver diseases (search) by enabling more targeted and effective treatment strategies.
The study was conducted through collaboration with Dr. Andrés Muro of the International Centre for Genetic Engineering and Biotechnology (search) (ICGEB) in Trieste, involving multidisciplinary contributions from molecular biologists, physicists, and bioinformaticians. The research received support from Fondazione Telethon, the Italian Ministry of Health, and the EU Horizon 2020 Program.