Uncovering the mechanisms of small vessel disease using a CRISPR-created induced pluripotent stem cell model

The contribution of vascular defects to neural degeneration has been recognised to be one of the key mechanisms underlying a wide range of dementia including Alzheimer Disease. However, the cellular and molecular mechanisms underlying the condition are still largely unknown, therefore, no efficient therapy is available. In the central nervous system (CNS), vascular cells and neuronal cells act synergistically to achieve complex regulation of CNS function, forming the neurovascular unit (NVU). Major cell types within the NVU include endothelial cells (ECs), pericytes or vascular smooth muscle cells (VSMCs), astrocytes and neurones. These neurovascular cells are functionally integrated and tightly regulated, providing a promising target for uncovering disease mechanisms for vascular dementia. Meanwhile, genetic cerebral small vessel diseases provide excellent model for understanding the contribution of vascular factors to the brain cognitive defect. From our previous study on a genetic vascular dementia syndrome, CADASIL (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), we have established patient specific induced pluripotent stem cell (iPSC) model, and differentiated the iPSCs into the neurovascular cell types, along with iPSC studies on the Alzheimer Disease. The iPSC models are promising human models to be used for dissecting functional contributions of each cell type within the NVU to the disease pathologies. However, the conventional 2D cell culture is unlikely to be able to recapitulate the complicated spatial and lateral interactions between the neurovascular cells. Through interdisciplinary collaboration, the PhD project will be creating new genetic small vessel disease model using CRISPR/Cas9 technology and constructing a human NVU using different combinations of nonvascular cells differentiated from disease-specific iPSCs and move towards 3D organ-chip technology. The 3D human NVU model will be thoroughly interrogated using molecular and cellular tools, in order to identify key factors or pathways that are common to vascular factor involved dementia, and identify biomarkers, then define drug targets informing future therapy.