Research activity

Liver-directed lentiviral gene transfer - The overall goal of this area is to define and tailor the best liver-directed lentiviral vector (LV)-based gene transfer strategy for monogenic diseases affecting liver function. While some diseases are non-cell autonomous diseases and relatively few hepatocytes producing enough transgene can correct the disease, other metabolic liver diseases are cell autonomous; thus, a relatively large functional cell mass is required for therapeutic benefit. Thus, it is important to determine the threshold of genetically corrected hepatocytes required for disease correction and assess whether cross-correction or selective advantage occurs in animal models of some inherited diseases, and to prioritize them based on the severity and age of onset and availability of alternative treatments, to establish which monogenic liver diseases will mostly benefit from LV gene therapy. Furthermore it is important to continue to investigate which biological barriers limit in vivo liver gene transfer by LV and how to overcome them, with a focus on the interactions of LV with the innate immune system and other cell types encountered during the journey from the blood to the liver, and to devise ways to modulate them, by both engineering LV and/or conditioning the host to better receive the therapeutic gene modification.

Liver-directed gene editing - Here we are exploring and developing targeted gene editing technologies as gene therapy strategies for inherited diseases of hepatic metabolism, as novel/complementary strategies to LV gene transfer. We are exploring both site-specific integration of transgenes into the endogenous genomic loci or into genomic safe harbors, permissive and tolerant to targeted integration, particularly in disease settings in which the endogenous regulation of transgene expression and/or the tissue contexts provide a rationale for targeted rather than semi-random LV-mediated transgene integration. We are also exploring targeted base editing approaches for selected disease indications, amenable to correction by tailored gene therapy strategies, also exploiting novel or ad-hoc generated mouse models, suitable to assess the efficacy and safety of the editing technologies.

Liver tissue dynamics - Maintenance of the genetic modification upon hepatocytes’ proliferation in liver growth and turnover requires targeting the cells underlying these processes. Little is known about postnatal liver growth and how different hepatocyte subsets contribute to it. We found that most hepatocytes are quiescent during liver growth, and a fraction of them generate most of the adult tissue. The overall goal of this area is to dissect hepatocyte heterogeneity in post-natal liver maturation and unravel its implications for in vivo gene engineering, to ultimately design and develop safe, effective, and durable gene therapies to treat diseases of hepatic metabolism in pediatric patients. To achieve this goal, we will characterize molecular programs of proliferating and quiescent hepatocyte subsets and assess their susceptibility to lentiviral gene transfer and nuclease-mediated gene editing, then estimate clonal dynamics of genetically modified hepatocytes in vivo and analyze gene signatures in human liver samples, to connect data on murine and human hepatocyte subsets.