Central nervous system (CNS) axons lose their intrinsic ability to regenerate upon maturity, whereas peripheral nervous system (PNS) axons do not. A key difference between these neuronal types is their ability to transport integrins into axons. Integrins can mediate PNS regeneration, but are excluded from adult CNS axons along with their Rab11 carriers. We reasoned that exclusion of the contents of Rab11 vesicles including integrins might contribute to the intrinsic inability of CNS neurons to regenerate, and investigated this by performing laser axotomy. We identify a novel regulator of selective axon transport and regeneration, the ARF6 guanine-nucleotide-exchange factor (GEF) EFA6 (also known as PSD). EFA6 exerts its effects from a location within the axon initial segment (AIS). EFA6 does not localise at the AIS in dorsal root ganglion (DRG) axons, and in these neurons, ARF6 activation is counteracted by an ARF GTPase-activating protein (GAP), which is absent from the CNS, ACAP1. Depleting EFA6 from cortical neurons permits endosomal integrin transport and enhances regeneration, whereas overexpressing EFA6 prevents DRG regeneration. Our results demonstrate that ARF6 is an intrinsic regulator of regenerative capacity, implicating EFA6 as a focal molecule linking the AIS, signalling and transport.This article has an associated First Person interview with the first author of the paper.

• Klíčová slova
• Axon initial segment, Axon regeneration, Axon transport, Integrin, Neuronal polarisation, Recycling endosome,
• MeSH
• alfa řetězce integrinu genetika   metabolismus   MeSH
• amyloidový prekurzorový protein beta genetika   metabolismus   MeSH
• axonální transport genetika   MeSH
• dendrity metabolismus   ultrastruktura   MeSH
• embryo savčí MeSH
• iniciální segment axonu metabolismus   ultrastruktura   MeSH
• krysa rodu Rattus MeSH
• malá interferující RNA genetika   metabolismus   MeSH
• mikrotubuly MeSH
• mozková kůra metabolismus   ultrastruktura   MeSH
• neurony metabolismus   ultrastruktura   MeSH
• potkani Sprague-Dawley MeSH
• primární buněčná kultura MeSH
• proteiny aktivující GTPasu genetika   metabolismus   MeSH
• Rab proteiny vázající GTP genetika   metabolismus   MeSH
• signální transdukce MeSH
• spinální ganglia metabolismus   ultrastruktura   MeSH
• výměnné faktory guaninnukleotidů antagonisté a inhibitory   genetika   metabolismus   MeSH
• vývojová regulace genové exprese MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alfa řetězce integrinu MeSH
• amyloidový prekurzorový protein beta MeSH
• malá interferující RNA MeSH
• proteiny aktivující GTPasu MeSH
• Psd protein, rat MeSH Prohlížeč
• Rab proteiny vázající GTP MeSH
• rab11 protein MeSH Prohlížeč
• výměnné faktory guaninnukleotidů MeSH

Neurons lose intrinsic axon regenerative ability with maturation, but the mechanism remains unclear. Using an in-vitro laser axotomy model, we show a progressive decline in the ability of cut CNS axons to form a new growth cone and then elongate. Failure of regeneration was associated with increased retraction after axotomy. Transportation into axons becomes selective with maturation; we hypothesized that selective exclusion of molecules needed for growth may contribute to regeneration decline. With neuronal maturity rab11 vesicles (which carry many molecules involved in axon growth) became selectively targeted to the somatodendritic compartment and excluded from axons by predominant retrograde transport However, on overexpression rab11 was mistrafficked into proximal axons, and these axons showed less retraction and enhanced regeneration after axotomy. These results suggest that the decline of intrinsic axon regenerative ability is associated with selective exclusion of key molecules, and that manipulation of transport can enhance regeneration.

• Klíčová slova
• axon regeneration, axonal transport, axotomy, endosomes, human, neuroscience, rat, small GTPases, trafficking,
• MeSH
• axony fyziologie   MeSH
• biologický transport MeSH
• buněčná diferenciace MeSH
• cytoplazmatické vezikuly metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• Rab proteiny vázající GTP metabolismus   MeSH
• regenerace * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Rab proteiny vázající GTP MeSH
• rab11 protein MeSH Prohlížeč