Approaches and Considerations Towards a Safe and Effective Adeno-Associated Virus Mediated Therapeutic Intervention for GM1-Gangliosidosis: A Dissertation

GM1 gangliosidosis is a lysosomal storage disorder caused by a deficiency in the catabolizing enzyme β-galactosidase (βgal). This leads to accumulation of GM1-ganglioside (GM1) in the lysosome inducing ER stress and cell death. GM1 gangliosidosis is primarily a disorder of the central nervous system (CNS) with peripheral organ involvement. In this work we report two major findings, 1) systemic treatment of GM1 gangliosidosis with an adenoassociated virus (AAV9) encoding mouse-βgal (mβgal) in a GM1 gangliosidosis mouse model (βGal-/-), and 2) an investigation into an intracranial injection of a therapeutic AAVrh8 encoding mβgal. Systemic treatment of GM1 gangliosidosis with AAV9 resulted in a moderate expression of enzyme in the CNS, reduction of GM1 storage, significant retention of motor function and a significant increase in lifespan. Interestingly, the therapeutic effect was more robust in females. Intracranial injections of AAVrh8 vector expressing high levels of βgal resulted in enzyme spread throughout the brain, significant retention of motor function and a significant increase in lifespan. Histological alterations were also found at the injection site in both βGal-/- and normal animals. We constructed a series of vectors with a range of decreasing enzyme expression levels to investigate the cause for the unanticipated result. Microarrays were performed on the injection site and we showed that a lower expressing AAVrh8-mβgal vector mitigated the negative response. Intracranial injection of this newly developed vector was shown to clear lysosomal storage throughout the CNS of βGal-/- mice. Taken together, these studies indicate that a combined systemic and fine-tuned intracranial approach may be the most effective in clearing lysosomal storage completely in the CNS while providing therapeutic benefit to the periphery

Midbody accumulation through evasion of autophagy contributes to cellular reprogramming and tumorigenicity

The midbody is a singular organelle formed between daughter cells during cytokinesis and required for their final separation. Midbodies persist in cells long after division as midbody derivatives (MB(d)s), but their fate is unclear. Here we show that MB(d)s are inherited asymmetrically by the daughter cell with the older centrosome. They selectively accumulate in stem cells, induced pluripotent stem cells and potential cancer \u27stem cells\u27 in vivo and in vitro. MB(d) loss accompanies stem-cell differentiation, and involves autophagic degradation mediated by binding of the autophagic receptor NBR1 to the midbody protein CEP55. Differentiating cells and normal dividing cells do not accumulate MB(d)s and possess high autophagic activity. Stem cells and cancer cells accumulate MB(d)s by evading autophagosome encapsulation and exhibit low autophagic activity. MB(d) enrichment enhances reprogramming to induced pluripotent stem cells and increases the in vitro tumorigenicity of cancer cells. These results indicate unexpected roles for MB(d)s in stem cells and cancer \u27stem cells\u27