Counteracting age-associated neurodegenerative diseases using chaperone-based amyloid disaggregases

A hallmark characteristic in neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) is the misfolding, aggregation, and accumulation of aberrant proteins leading to cellular dysfunction, loss of synaptic connections, apoptosis, and brain damage. Dementia is one of the prominent pathological symptoms of these diseases and more than 400,000 Australians are currently diagnosed and around 6.4 million cases will be identified at a cost of one trillion dollars in the next 40 years. These disorders typically manifest among aging populations contributing to increased morbidity and poor quality of life. Despite global efforts to bolster dementia research, there are currently no effective treatments or cures. In healthy cells, protein misfolding and aggregation are counteracted by a multi-tiered protein quality control system mediated by molecular chaperones and proteases. The Nillegoda Group is pioneering in characterizing a new class of protein aggregate solubilizing machines (disaggregases) in human cells that can efficiently solubilize and clear cytotoxic protein (e.g. amyloid) aggregates. These disaggregases are constituted by the Heat shock protein 70 (Hsp70) chaperone system. This discovery introduced a previously unacknowledged metazoan cellular repair activity fundamentally important for decreasing cellular aggregate levels and the associated cytotoxicities linked to neurodegeneration. Currently, there are no methods that can activate protein disaggregation function in human cells. Engineering strategies to rapidly and specifically promote aggregate solubilization/clearance and promote repair/survival of degenerating neurons will be invaluable for devising proteostasis-based treatments applicable against a broad range of neurodegenerative disorders. The core premise of this research project is to develop novel methods to boost protein disaggregation function in human cells. The approaches involve cutting edge cell biology and biochemical approaches including gene editing (CRISPR-Cas9), high-resolution fluorescence microscopy and FACS, optogenetics, proximity-based ex-vivo protein-protein interaction techniques, protein purification and characterization, and high throughput screening for small molecules that modulate protein disaggregation and cell repair. The outcomes of this work will include delivering small molecules with anti-neurodegeneration activity. The chaperone-based optogenetics tools for the first time will offer spatial precision, e.g. to activate/inactivate protein disaggregation/clearance in selected organelles, cell types or tissues ex vivo and in vivo. This foundational work will set the stage for the development of therapeutically valuable novel approaches to boost amyloid clearance, repair neurons and counteract neurodegenerative disorders. Relevant publications: Wentink AS, Nillegoda NB, et al., Molecular dissection of amyloid disaggregation by the human Hsp70 chaperone machinery (In press) Nature. 2020 Nillegoda NB et al., Crucial Hsp70 co-chaperone complex unlocks metazoan protein disaggregation. Nature. 2015 Nillegoda NB et al., Evolution of an intricate J-protein network driving protein disaggregation in eukaryotes. eLife. 2017 Kirstein J, et al., In vivo properties of the disaggregase function of J-domain proteins and Hsc70 in C. elegans stress and aging. Aging Cell. 2017 Gao X, et al., Human Hsp70 disaggregase reverses Parkinson’s-linked α-synuclein amyloid fibrils. Mol Cell. 2015 Rosenzweig R*, Nillegoda NB*, et al., The Hsp70 chaperone network. Nat Rev Mol Cell Biol. 2019 (Review)