Lentiviral Hematopoietic Stem Cell Gene Therapy Rescues Clinical Phenotypes in a Murine Model of Pompe Disease

Abstract

Pompe disease is a lysosomal storage disorder caused by malfunctions of the acid alpha-glucosidase (GAA) enzyme with a consequent toxic accumulation of glycogen in cells. Muscle wasting and hypertrophic cardiomyopathy are the most common clinical signs that can lead to cardiac and respiratory failure within the first year of age in the more severe infantile forms. Currently available treatments have significant limitations and are not curative, highlighting a need for the development of alternative therapies. In this study, we investigated the use of a clinically relevant lentiviral vector to deliver systemically GAA through genetic modification of hematopoietic stem and progenitor cells (HSPCs). The overexpression of GAA in human HSPCs did not exert any toxic effect on this cell population, which conserved its stem cell capacity in xenograft experiments. In a murine model of Pompe disease treated at young age, we observed phenotypic correction of heart and muscle function with a significant reduction of glycogen accumulation in tissues after 6 months of treatment. These findings suggest that lentiviral-mediated HSPC gene therapy can be a safe alternative therapy for Pompe disease.

Screening of Chimeric GAA Variants in a Preclinical Study of Pompe Disease Results in Candidate Vector for Hematopoietic Stem Cell Gene Therapy

“…Interestingly, in our study, although GAA enzyme activity was detectable in the brain of mice in the GAAco group at approximately 11% and 30% of wildtype levels in cerebrum and cerebellum respectively, glycogen level was not reduced. This confirms previously reported results, in which glycogen in the CNS was not reduced through HSPC gene therapy using solely the GAA sequence (10,16). Surprisingly, although GAA enzyme activity in the GILT-tagged groups in the brain was below detectable enzyme activity levels, lysosomal glycogen was completely reduced to wildtype levels, which was confirmed by near absence of histological PAS staining.…”

“…3B). Previous studies showed that lentiviral HSPC gene therapy using a GAA transgene effectively reduced heart glycogen levels (10,11,16), but also in our study more than 99% reduction was observed in all the therapeutic groups (except GILTco1-m-ApoE1) at week 16 (Fig. 3C) when compared to Gaa -/mice (441.44 µg glycogen/mg protein; Fig.…”

“…Using weaker promoters, such as locus control region of the b-globin chain fused to the elongation factor 1a promoter (LCR-EFS), that upregulate expression in the erythrocyte lineage, have been shown to be safe in murine and human HSPCs but had limited therapeutic response in skeletal muscle and CNS (16). Furthermore, in contrast to ERT and AAV therapies, in which immune responses against the rhGAA protein, viral vector or transgene product could affect efficacy (17)(18)(19)(20), allogeneic HSPC transplantation was shown to promote immune tolerance induction to infusion of recombinant alpha-L-iduronidase (IDUA) in Hurler disease patients (21).…”

Gene Therapy for Lysosomal Storage Disorders: Ongoing Studies and Clinical Development

“…Numerous pre-clinical studies of HSC-GT have been performed in Pompe disease [ 104 , 105 , 106 , 107 ]. Pompe disease is caused by a deficiency of the acid alpha-glucosidase (GAA) enzyme due to mutations in the GAA gene, resulting in the accumulation of lysosomal glycogen in a variety of cell types.…”

Case Report: Anesthetic Management and Electrical Cardiometry as Intensive Hemodynamic Monitoring During Cheiloplasty in an Infant With Enzyme-Replaced Pompe Disease and Preserved Preoperative Cardiac Function

“…Otherwise, even in the era of ERT, there were still some limitations in treating Pompe disease, such as great expense, immune response due to high amounts of exogenous enzyme, progression of muscle weakness even responding well to ERT initially ( 30 ), limited effects to central nervous system due to blood brain barrier ( 31 ), and white matter abnormalities/ventricular enlargement in brain MRI ( 32 ). Some alternative therapies have been developed, like gene therapy ( 33 , 34 ), enzyme enhancement therapy ( 35 ), and substrate reduction therapy ( 36 ). Further studies were required to determine the benefits of these treatments in decreasing perioperative risks for Pompe disease.…”