31 research outputs found
Production and Isolation of Axons from Sensory Neurons for Biochemical Analysis Using Porous Filters
XIAP Regulates Caspase Activity in Degenerating Axons
Our knowledge of the destructive events that regulate axonal degeneration is rudimentary. Here, we examine the role of caspases and their endogenous inhibitor, the X-linked inhibitor of apoptosis protein (XIAP), in axonal degeneration of dorsal root ganglion (DRG) axons. We show that caspase-3, caspase-6, and caspase-9 are present in axons and are cleaved upon nerve growth factor (NGF) withdrawal. We observed that caspase-3 activity is high in NGF-withdrawn axons and that CASP3â/â axons are protected from degeneration. XIAPâ/â DRG sensory neurons degenerate more rapidly and contain more active caspase-3 than their wild-type counterparts, indicating that axonal caspases are normally regulated by XIAP. Importantly, axonal XIAP levels drop sharply after NGF withdrawal; if XIAP levels are maintained by overexpression, axonal caspase-3 activation and axonal degeneration are suppressed. Finally, we show that XIAPâ/â embryos have stunted dermal innervation. We propose that XIAP-mediated caspase inhibition plays an important role in regulating morphogenic events that shape the nervous system during development