Improvement of motor and behavioral activity in Sandhoff mice transplanted with human CD34+ cells transduced with a HexA/HexB expressing lentiviral vector

Abstract

Background Tay–Sachs and Sandhoff disease are debilitating genetic diseases that affect the central nervous system leading to neurodegeneration through the accumulation of GM2 gangliosides. There are no cures for these diseases and treatments do not alleviate all symptoms. Hematopoietic stem cell gene therapy offers a promising treatment strategy for delivering wild‐type enzymes to affected cells. By genetically modifying hematopoietic stem cells to express wild‐type HexA and HexB, systemic delivery of functional enzyme can be achieved. Methods Primary human hematopoietic stem/progenitor cells and Tay–Sachs affected cells were used to evaluate the functionality of the vector. An immunodeficient and humanized mouse model of Sandhoff disease was used to evaluate whether the HexA/HexB lentiviral vector transduced cells were able to improve the phenotypes associated with Sandhoff disease. An immunodeficient NOD‐RAG1−/‐IL2−/− (NRG) mouse model was used to evaluate whether the HexA/HexB vector transduced human CD34+ cells were able to engraft and undergo normal multilineage hematopoiesis. Results HexA/HexB lentiviral vector transduced cells demonstrated strong expression of HexA and HexB and restored enzyme activity in Tay–Sachs affected cells. Upon transplantation into a humanized Sandhoff disease mouse model, improved motor and behavioral skills were observed. Decreased GM2 gangliosides were observed in the brains of HexA/HexB vector transduced cell transplanted mice. Increased peripheral blood levels of HexB was also observed in transplanted mice. Normal hematopoiesis in the peripheral blood and various lymphoid organs was also observed in transplanted NRG mice. Conclusions These results highlight the potential use of stem cell gene therapy as a treatment strategy for Tay–Sachs and Sandhoff disease.

Functional rescue in an Angelman syndrome model following treatment with lentivector transduced hematopoietic stem cells

“…The work presented here highlights our effort to develop the use of HSPC transduced with a lentiviral vector expressing Ube3a , in an innovative preclinical model of AS, which offers a promising strategy for life-long delivery of functional UBE3A through the hematopoietic system to the brain. This cross-correction approach has been successfully demonstrated for other monogenic diseases including adrenoleukodystrophy, metachromatic leukodystrophy and Sandhoff disease ( 22 , 31 , 32 , 49 ). In previous studies, successful engraftment of gene-modified microglia in the brains of treated mice demonstrated that HSPC gene therapy can deliver therapeutic proteins to disease-affected cells ( 22 , 30 , 32–34 , 49 ).…”

“…This cross-correction approach has been successfully demonstrated for other monogenic diseases including adrenoleukodystrophy, metachromatic leukodystrophy and Sandhoff disease ( 22 , 31 , 32 , 49 ). In previous studies, successful engraftment of gene-modified microglia in the brains of treated mice demonstrated that HSPC gene therapy can deliver therapeutic proteins to disease-affected cells ( 22 , 30 , 32–34 , 49 ). In our current study, we observed elevated levels of UBE3A in the brains of the Ube3a-HET treatment group, and rescue of motor, cognitive and EEG phenotypes following transplantation and engraftment of the genetically modified human CD34+ HSPC as neonates or adults.…”

“…Our study, for the first time, illustrated rigorous reversal of many phenotypes in both neonate and adult treated mice using HSPC transduced with a Ube3a -expressing lentiviral vector. Gene modified lentiviral vectors have been applied in different clinical trials based on ex vivo correction of autologous HSPC and were demonstrated to be immunologically safe and therapeutically efficient in symptom correction in a wide range of single gene disorders ( 22 , 31 , 32 ). Yet still, for nearly all rare genetic disorders, including AS, there is a delay between developmental milestones not being met and an official diagnosis of a genetic syndrome.…”

A Novel Huntington's Disease Mouse Model to Assess the Role of Neuroinflammation on Disease Progression and to Develop Human Cell Therapies

“…To assess the role of the immune system, a cohort of age-and sex-matched YACNSG mice were given a human immune system at postnatal day 2-5 following previously established protocols. [23][24][25] The humanized YACNSG were then longitudinally assessed alongside the parental YAC128 strain and nonhumanized YACNSG. Following assessment of the level of "humanization", functional assessment began at 4 months and was continued until the mice were 12 months old.…”

“…Humanization of YACNSG mice followed established protocols. [23][24][25] Briefly, human CD34+ hematopoietic stem and progenitor cells (HSPC) were isolated from umbilical cord blood obtained from the UC Davis Umbilical Cord Collection Program by Ficoll-Paque (GE Healthcare, Logan, Utah) density gradient. They were further purified by CD34 magnetic bead column separation (Miltenyi Biotec, Auburn, California).…”