Axonal degeneration in the peripheral nervous system: Implications for the pathogenesis of amyotrophic lateral sclerosis

Axons are the anatomical link between neuronal cell bodies and their target organs, and thus axonal degeneration is the pathological substrate that underlies neurological dysfunction in a large number of neurological conditions. Recent advances in the field of axonal biology demonstrate that axons possess programs for survival and degeneration that are distinct from those of the cell body, indicating that therapeutic strategies must consider protection of both the cell body and the axon. This review discusses axonal degeneration in the peripheral nervous system (PNS) with a focus on amyotrophic lateral sclerosis, examining both the underlying mechanisms, and the cellular and disease models of axonal degeneration that relate to disease pathogenesis.