Elsevier

Neurobiology of Aging

Volume 36, Issue 2, February 2015, Pages 971-981
Neurobiology of Aging

Regular article
Axonal transport declines with age in two distinct phases separated by a period of relative stability

https://doi.org/10.1016/j.neurobiolaging.2014.09.018Get rights and content
Under a Creative Commons license
open access

Abstract

Axonal transport is critical for supplying newly synthesized proteins, organelles, mRNAs, and other cargoes from neuronal cell bodies into axons. Its impairment in many neurodegenerative conditions appears likely to contribute to pathogenesis. Axonal transport also declines during normal aging, but little is known about the timing of these changes, or about the effect of aging on specific cargoes in individual axons. This is important for understanding mechanisms of age-related axon loss and age-related axonal disorders. Here we use fluorescence live imaging of peripheral nerve and central nervous system tissue explants to investigate vesicular and mitochondrial axonal transport. Interestingly, we identify 2 distinct periods of change, 1 period during young adulthood and the other in old age, separated by a relatively stable plateau during most of adult life. We also find that after tibial nerve regeneration, even in old animals, neurons are able to support higher transport rates of each cargo for a prolonged period. Thus, the age-related decline in axonal transport is not an inevitable consequence of either aging neurons or an aging systemic milieu.

Keywords

Axonal transport
Aging
Nicotinamide mononucleotide Adenylyltransferase 2
Mitochondrial transport
Axon regeneration
Fluorescence live imaging

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This is an open access article under the CC BY-NC-SA license (http://creativecommons.org/licenses/by-nc-sa/3.0/).

1

S.M. and R.A. contributed equally to this work.