title: Cargo distributions differentiate pathological axonal transport impairments.
abstract: Axonal transport is an essential process in neurons, analogous to shipping goods, by which energetic and cellular building supplies are carried downstream (anterogradely) and wastes are carried upstream (retrogradely) by molecular motors, which act as cargo porters. Impairments in axonal transport have been linked to devastating and often lethal neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis, Huntington's, and Alzheimer's. Axonal transport impairment types include a decrease in available motors for cargo transport (motor depletion), the presence of defective or non-functional motors (motor dilution), and the presence of increased or larger cargos (protein aggregation). An impediment to potential treatment identification has been the inability to determine what type(s) of axonal transport impairment candidates that could be present in a given disease. In this study, we utilize a computational model and common axonal transport experimental metrics to reveal the axonal transport impairment general characteristics or "signatures" that result from three general defect types of motor depletion, motor dilution, and protein aggregation. Our results not only provide a means to discern these general impairments types, they also reveal key dynamic and emergent features of axonal transport, which potentially underlie multiple impairment types. The identified characteristics, as well as the analytical method, can be used to help elucidate the axonal transport impairments observed in experimental and clinical data. For example, using the model-predicted defect signatures, we identify the defect candidates, which are most likely to be responsible for the axonal transport impairments in the G93A SOD1 mouse model of ALS.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA. cassie.mitchell@bme.gatech.edu
authors.forename: Cassie S
authors.initials: CS
authors.lastname: Mitchell
authors.forename: Robert H
authors.initials: RH
authors.lastname: Lee
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology; D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D004195:Disease Models, Animal; D006801:Humans; D051379:Mice; D008959:Models, Neurological; D020409:Molecular Motor Proteins / Q000502:physiology; D019636:Neurodegenerative Diseases / Q000503:physiopathology*; D016900:Neurofilament Proteins / Q000502:physiology; D017510:Protein Folding; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1
chemical_list: D020409:Molecular Motor Proteins; D016900:Neurofilament Proteins; C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1