Identifying mechanisms that regulate local axon vulnerability to pathological degeneration

Neurodegenerative disorders represent a significant challenge to human health. Many therapeutic strategies revolve around suppressing death of the neuronal cell body. However, neuronal connectivity depends on long projections called axons that use specialized mechanisms to survive in isolation from the soma. The degeneration of axons is a common, sometimes initiating event in a variety of neurodegenerative disorders including Alzheimer’s disease, Parkinson’s disease, and peripheral neuropathies. Protecting axon health is necessary for sustaining functional connectivity and will have broad relevance to many diseases. Disease onset and severity can vary significantly between patients suggesting there are important, undiscovered factors that influence axon vulnerability to pathological degeneration. The goal of this project is to define novel pathways controlling the fate of a damaged axon. Axon injury stimulates a local self-destruct mechanism that promotes axon dismantling and clearance by the immune system. The enzymes NMNAT2 and SARM1 represent a critical regulatory node in this self-destruction program. Boosting NMNAT2 is neuroprotective and has therapeutic potential. We will define a new mechanism controlling NMNAT2 abundance in axon segments. We will also identify new contributions for autophagy in axon susceptibility and stress signaling. These studies will generate new insight on local mechanisms controlling axon health and reveal new treatment opportunities in neurodegenerative diseases.