MODELING TRAFFIC JAMS IN SLOW AXONAL TRANSPORT

Abstract

The purpose of this paper is to develop a model capable of simulating traffic jams in slow axonal transport. Slowing of slow axonal transport is an early sign of some neurodegenerative diseases. Axonal swellings observed near the end stage of such diseases may be an indication of traffic jams developing in axons that cause the slowing down of slow axonal transport. Traffic jams may result from misregulation of microtubule-associated proteins caused by an imbalance in intracellular signaling or by mutations of these proteins. This misregulation leads to a decay of microtubule tracks in axons, effectively reducing the number of "railway tracks" available for molecular-motor-assisted transport of intracellular organelles. In this paper, the decay of microtubule tracks is modeled by a reduction of the number density of microtubules in the central part of the axon. Simulation results indicate that the model predicts the build-up of the bell-shaped concentration wave, as the wave approaches the bottleneck (blockage) region. This increase in concentration will likely plug the bottleneck region resulting in a traffic jam that would hinder the slow axonal transport.