| Reference : INCREASING THE COMPLEXITY OF MIDBRAIN ORGANOID SYSTEMS FOR DEVELOPMENTAL STUDIES AND ... |
| Dissertations and theses : Doctoral thesis | |||
| Human health sciences : Neurology | |||
| Systems Biomedicine | |||
| http://hdl.handle.net/10993/50803 | |||
| INCREASING THE COMPLEXITY OF MIDBRAIN ORGANOID SYSTEMS FOR DEVELOPMENTAL STUDIES AND DISEASE MODELLING | |
| English | |
Sabaté Soler, Sonia  [University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Life Sciences and Medicine (DLSM) >] | |
| 23-Mar-2022 | |
| University of Luxembourg, Belvaux, Luxembourg | |
| Docteur en Biologie | |
| 216 | |
| Schwamborn, Jens Christian | |
| [en] Neurobiology ; Microglia ; Organoids ; iPSCs ; Cell culture models | |
| [en] The discovery of iPSC technology revolutionized the biomedical field, allowing the
development of translatable and complex 2D and 3D cell culture systems. Organoids are 3D models containing multiple cell types that mimic complex microenvironments. This is highly advantageous to understand human development, physiology and disease, especially in inaccessible areas such as the brain. Human midbrain-specific organoids have been developed to study the midbrain (abundant in dopaminergic neurons). In Parkinson’s Disease (PD), dopaminergic neurons in the substantia nigra of the midbrain degenerate, causing a broad spectrum of clinical features. Midbrain organoids (MO) are rich in dopaminergic neurons, and contain spatially organized groups of neural cells and progenitors. MO generated from PD patients’ cells recapitulate dopaminergic neuron degeneration. In this thesis, we first demonstrated that dopaminergic neuron PD phenotypes and drug rescue effects were similar between MO and mice. After, we identified different neuronal clusters, progenitor cells, radial glia and mesenchymal cells in MO by scRNA-Seq. As expected, due to the neuro-ectodermal patterning of the MO’ starting cell population, we confirmed the absence of mesoderm-derived cell types, such as microglia and endothelial cells. This represents a limitation for the system in terms of cellular and molecular complexity. Microglia in the human brain perform surveillance, defence and homeostasis functions; they phagocytose metabolic waste products and cell debris. We successfully developed a novel protocol to integrate functional microglia into our MO model. SnRNA-Seq analysis and electrophysiological results suggested a reduction of stress levels and higher maturation of neurons in the presence of microglia, respectively. We then aimed to vascularise MO, which would better recapitulate the brain environment and improve oxygen and nutrient supply into the organoid core (a common 3D culture limitation). We integrated an endothelial network into MO by fusion with vascular organoids, and observed the presence of blood vessel components like pericytes and basal lamina. Furthermore, vascularized assembloids showed decreased levels of cell death and hypoxia. Finally, by co-culturing microglia with vascularized assembloids, we modelled the neurovascular unit in 3D. Altogether, this work contributes to the development of advanced 3D region-specific organoids, which better recapitulate the complexity of the human brain. These novel MO systems represent one step further into modelling neuroinflammation and blood brain barrier disruption, typical from neurodegenerative disorders such as PD, which might lead to more reliable and personalized medical approaches. | |
| Luxembourg Centre for Systems Biomedicine (LCSB) | |
| http://hdl.handle.net/10993/50803 |
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