Untangling how Metal Dyshomeostasis Pathologically Interacts with Protein Aggregates to Drive Neurodegeneration

Details

Lewy Body Dementia (LBD) consists of two syndromes, Dementia with Lewy Bodies (DLB) and Parkinson’s Disease with Dementia (PDD). Cognitive and motor symptom order differs, but phenotypes eventually converge. Dopaminergic (DA) neurons within a midbrain structure, the Substantia Nigra pars compacta, degenerate extensively during both LBD syndromes. Pathological molecular interactions between misfolded protein aggregates (e.g. α-synuclein (αSYN) and tau) forming within DA-SNpc neurons, the ‘metalome’ (free metal ion distribution), and mitochondria—encoding oxidative phosphorylation components to biochemically generate cellular energy—may cause progressive neurodegeneration. Furthermore, the dopamine precursor Levodopa, used as a ‘gold-standard’ treatment in LBD and also Parkinson’s disease, may further disrupt this triad of interactors, to driving the disease further.

To untangle this pathological interplay, this project will use methods optimised in our labs applied to patient-derived cell models and human post-mortem brain samples. For insight into toxic metal-related pathways activated by accumulation of the dementia-associated protein species, we will apply label-free synchrotron X-ray fluorescence (XRF) metal imaging to map metal element distribution in individual DA-SNpc neurons of post-mortem human brain samples, comparing control, DLB and PDD cases’ relative levels. Neurons will be mapped at >2 μm resolution, permitting accurate discrimination of individual metal elements: redox-active transition metals (e.g. iron (Fe) and copper (Cu)) and biometals (e.g. zinc (Zn) and calcium (Ca)), all essential for brain function.

PyMCA software will fit multi-element XRF spectra per pixel to produce distribution intensity maps per metal element from individual neurons. Polarized light microscopy will screen for pathological protein structures. To dissect metalome-mitochondrial cause-effect relationships, the DLB vs PDD-related metal dyshomeostasis patterns will be modelled in 3D dopaminergic human neuronal in vitro models treated with human αSYN protein aggregates, using an established protocol from our lab, and the identified dysregulated metal specie(s)followed by mitochondrial functional profiling, e.g. mass spectrometry-based mitochondrial metabolomics and Seahorse-based respiratory analysis. Using this model system we will further profile how the use of Levodopa, at clinically-relevant dosages, might further amplify the mitochondrial respiratory pathology.

The project will allow a student to acquire state-of-the-art molecular biology, biochemistry and biophysical techniques, and attain expertise in using a variety of software packages, all whilst being highly clinically translational. The project will take place at the University of Birmingham, a top UK University that forms part of the prestigious Russell group of research-intense universities.

To apply, please contact Dr Ilse Pienaar at i.pienaar@bham.ac.uk.