Next gEneration treatment of lysosomal aciD lipasE Deficiency – NEEDED

Lysosomal acid lipase (LAL) deficiency is a rare, autosomal recessive condition caused by mutations in the gene encoding for LAL. Wolman disease (WD) is the most severe form with an incidence of 1 in 300.000 livebirth, resulting in failure to thrive, hepatomegaly, and hepatic failure, and a life expectancy of 3-8 months.
Enzyme replacement therapy using Sebelipase ?, a recombinant human LAL, is a very promising treatment, but access, frequent infusion and cost represent clear impediments to this life-long treatment. Allogenic hematopoietic stem cells (HSC) transplantation might be curative; however, it suffers of several post-transplantation complications.
To minimize these issues, we proposed to transplant gene corrected autologous HSC. For this we will take advantage of a new lal-/- mouse model. Mouse HSC will be collected and ex vivo modified to express supraphysiological levels of the missing enzyme, which are required to correct the pathology when HSC are reintroduced into the patient. To stably insert the LAL transgene we will take advantage of the CRISPR/Cas9 system to achieve integration in the a-globin locus, which guarantees safe and effective transgene expression in the erythroid lineage. To easily follow in time disease progression and treatment, we will establish a pipeline to analyze lipids and lysosomes accumulation in blood cells using imaging flow cytometry. Finally, for clinical translation, we will optimize donor DNA delivery in human HSC by replacing AAV vector with a novel integrase defective lentiviral vector. Briefly, the proposal has 4 aims: 1) to find an effective treatment for WD; 2) to establish a novel analysis pipeline to follow WD treatment; 3) to develop novel donor DNA vector template; 4) to establish an HSC based GT platform for protein replacement therapy. This research will pave the way for the development of a novel and urgently needed gene therapy approach for WD, as well as for other lysosomal storage disorders.