In vivo haemopoietic stem cell gene therapy enabled by postnatal trafficking
Michela Milani, Anna Fabiano, Marta Perez-Rodriguez, Raisa Jofra Hernández, Alessandra Zecchillo, Erika Zonari, Sofia Ottonello, Luca Basso‐Ricci, Cesare Canepari, Monica Volpin, Valeria Iannello, Valentina Capo, Pamela Quaranta, Luca Seffin, Fabio Russo, Mauro Biffi, Leonardo Ormoli, Chiara Brombin, Filippo Carlucci, Antonella Forlino, Marta Filibian, Eugenio Montini, Serena Scala, Anna Villa, Juan A. Bueren, Paula Rı́o, Alessandro Aiuti, Alessio Cantore, Luigi Naldini
Abstract
Lentiviral vector (LV)-mediated ex vivo gene therapy for haematopoietic stem and progenitor cells (HSPCs) has delivered on the promise of a ‘one-and-done’ treatment for several genetic diseases1. However, ex vivo manipulation and patient conditioning before transplantation are major hurdles that could be overcome by an in vivo approach. Here we demonstrate that in vivo gene delivery to HSPCs after systemic LV administration is enabled by the substantial trafficking of these cells from the liver to the bone marrow in newborn mice. We improved gene-transfer efficiency using a phagocytosis-shielded LV, successfully reaching bona fide HSPCs capable of long-term multilineage output and engraftment after serial transplantation, as confirmed by clonal tracking. HSPC mobilization further increased gene transfer, extending the window of intervention, although permissiveness to LV transduction declined with age. We successfully tested this in vivo strategy in mouse models of adenosine deaminase deficiency, autosomal recessive osteopetrosis and Fanconi anaemia. Interestingly, in vivo gene transfer provided a selective advantage to corrected HSPCs in Fanconi anaemia, leading to near-complete haematopoietic reconstitution and prevention of bone marrow failure. Given that circulating HSPCs in humans are also most abundant shortly after birth, in vivo HSPC gene transfer holds strong translational potential across multiple diseases. In vivo gene delivery to haematopoietic stem and progenitor cells in newborn mice using engineered lentiviral vectors shows promise as an effective treatment for genetic diseases.