Deciphering Neurodegenerative Disease with fast 3D imaging & functional nanoscopy

Neurodegenerative diseases are incurable, progressive brain disorders associated with accumulation of aberrant protein aggregates with severe effects on movement and mental functioning. The mechanism leading to neurotoxicity is far from understood, due to our lack of insight into early processes. Recently, aberrant liquid-liquid phase separation has emerged as a new concept to explain protein aggregation in neurodegenerative disease. Here, I will investigate the biophysical basis of the formation of different material states of aggregates, by capitalizing on my expertise at the interface of single-molecule biophysics and quantitative, high-resolution imaging in cells.I propose to address the following key questions, with the use of cellular models of Huntingtons Disease (HD) complemented with well-controlled in vitro experiments: How do the physico-chemical properties of protein variants and the cellular environment influence aggregation and toxicity? What role does phase separation play in Huntingtons disease? How does prion-like spreading of extracellular protein interfere with local protein assemblies in cells? HD is caused by a gene defect resulting in aggregation-prone huntingtin protein. The diverse sizes (nm-m) and conformations of the aggregates pose a remarkable challenge, and multiple complementary approaches are needed to unravel their morphology and physico-chemical properties. I will develop multimodal AI-informed quantitative microscopy and functional nanoscopy to decipher how aggregates in neurodegenerative disease form and mature. Importantly, we will work without tags and exploit virtually stained quantitative phase imaging to assess mechanical properties and cell pathophysiology, therefore minimizing interference with aggregation processes. The QScope project is expected to elucidate the role of protein aggregation and phase transitions, relevant for a broad variety of diseases, and to establish new label-free and super-resolution imaging.