Advanced technologies for neural transplantation: new approaches for neural repair and modelling diseases

© 2019 Stefano FrausinMany neurological diseases affecting the central nervous system are still incurable because of the scarce and incomplete knowledge of disease mechanisms and the lack of effective treatments. Despite the effort, these disorders represent a challenge for medical science. The poorly representative disease models and technical limitation in deriving and characterising neural cells after transplantation into animal model hindered the development of new therapies. Cell therapy has become a promising therapeutic approach for diseases characterised by cell loss, although significant hurdles need to be overcome before it can be progressed into mainstream therapies. Today, brain tumours remain incurable and there are no therapies able to cure these diseases. Well-defined GBM in vivo models and cellular technologies might be useful for the investigation of pathophysiological mechanisms regulating brain tumours, helping the development of new therapeutic strategies. This thesis explores the potential and the limitations of using human gene manipulated cell lines into different disease contexts: cell therapy for motor neuron disease (MND) and brain tumours. Using a differentiation protocol, we investigated the possibility to derive and characterise spinal motor neurons (spMNs) derived from human pluripotent stem cells (hPSCs). We demonstrated that the specification of different spMN subtypes can be regulated using a combination of small molecules for defined timing. These results contribute to clarify important human developmental aspects and to propose an in vitro source of spMNs useful to study disease mechanisms and propose a cell-based therapy for MND. Accordingly, we conducted a systematic evaluation of the abilities and properties of spMNs derived from different reporter hPSC lines after transplantation into the rat spinal cord. This research highlight that grafted cells require a period of 6 months to mature and integrate into the host spinal motor circuitry. This study demonstrates that stem cell therapy might be a promising approach for treating diseases affecting the central nervous system and characterised by cell loss. Two reporter tumour cell lines derived from patient biopsies were grafted into the brain of athymic mice to establish, study and characterise an animal model of GBM. The results highlight the utility of tagged cells in brain tumour research, which allow us to better understand not only the tumour generation and progression but also evaluate the efficacy of new treatments. Furthermore, we presented a new tool for studying the role of ions in GBM, the chemogenic platform DREADD. GBM cells were engineered to express Designer Receptors Exclusively Activated by Designer Drugs (DREADD) and used to chronically manipulate calcium and potassium homeostasis in order to evaluate their effect on cell metabolism and cell behaviour in vivo. Our results show that these ions are involved in key tumour mechanisms such as cell proliferation and migration. This work contributes to a mixed literature where there has been conjecture as to whether the dysregulation of ions homeostasis is responsible of key tumour mechanisms. Taken together, these studies offer new tools that might be useful for the understanding and comprehension of biological events related to a huge number of diseases affecting the central nervous system and will have implications in clinical approaches for treating MND and GBM