Year 2

ALS is a progressive neurodegenerative disease that primarily affects motor neurons (MNs). It results in paralysis and loss of control of vital functions, such as breathing, leading to premature death. Much scientific evidence indicates that ALS is due to the buildup of toxic misfolded proteins in key neuronal populations that leads to neurodegeneration. In this CIRM-funded project, we are developing drugs that can improve a cellular process called “autophagy” by which cells, including neurons, clear out built-up toxic misfolded proteins and increase their longevity. We had discovered that a series of FDA-approved drugs already on the market for other indications happen to induce autophagy in a manner that is independent of their original purpose. Our goal is to study these FDA-approved drugs and determine whether any of them can induce autophagy and slow neurodegeneration in ALS patient stem cell-derived neurons, and to repurpose these drugs for ALS. To date, we have made significant progress towards testing these drugs on neurons that we derived from induced pluripotent stem cells engineered from skin cells taken from ALS patients. We have built robotic microscopes that can rapidly image ALS patient neurons that are treated with drugs in the lab and determine whether any of these “autophagy-inducing” FDA-approved drugs slowdown the rate of neurodegeneration. We have optimized large-scale methods to grow patient neurons, treat them with drugs, image them over many days, and analyze the images to measure neurodegeneration. In August 2014, we published a paper in the journal Nature Chemical Biology that showed two FDA-approved drugs can in fact induce autophagy and increase the clearing of an ALS-related protein called TDP43 in neurons. We have now obtained stem cells from broader types of familial ALS as well as sporadic ALS patients, have made neurons from their stem cells, and have treated their stem cell-derived neurons with more than 10 autophagy-inducing drugs at varying concentrations to determine whether autophagy-inducers can slow neurodegeneration in neurons from broader forms of ALS. We have found one of these drugs shows beneficial effects on neurons from several patients. We are currently strategizing a way to test these in living animals and determine whether they can induce autophagy in brain cells of living animals.