Full recovery from spinal cord injury requires axon regeneration to re-establish motor and sensory pathways. In mammals, the failure of sensory and motor axon regeneration has many causes intrinsic and extrinsic to neurons, amongst which is the lack of adhesion molecules needed to interact with the damaged spinal cord. This study addressed this limitation by expressing the integrin adhesion molecule α9, along with its activator kindlin-1, in sensory neurons via adeno-associated viral (AAV) vectors. This enabled sensory axons to regenerate through spinal cord injuries and extend to the brainstem, restoring sensory pathways, touch sensation and sensory behaviours. One of the integrin ligands in the injured spinal cord is tenascin-C, which serves as a substrate for α9β1 integrin, a key receptor in developmental axon guidance. However, the adult PNS and CNS neurons lack this receptor. Sensory neurons were transduced with α9 integrin (which pairs with endogenous β1 to form a α9β1 tenascin receptor) together with the integrin activator kindlin-1. Regeneration from sensory neurons transduced with α9integrin and kindlin-1 was examined after C4 and after T10 dorsal column lesions with C6,7 and L4,5 sensory ganglia injected with AAV1 vectors. In animals treated with α9 integrin and kindlin-1, sensory axons regenerated through tenascin-C-expressing connective tissue strands and bridges across the lesions and then re-entered the CNS tissue. Many axons regenerated rostrally to the level of the medulla. Axons grew through the dorsal grey matter rather than their normal pathway the dorsal columns. Growth was slow, axons taking 12 weeks to grow from T10 to the medulla, a distance of 4-5 cm. Functional recovery was confirmed through cFos activation in neurons rostral to the injury after nerve stimulation and VGLUT1/2 staining indicating new synapse formation above the lesion. Behavioural recovery was seen in both heat and mechanical sensation, as well as tape removal tests. This approach demonstrates the potential of integrin-based therapies for long distance sensory axon regeneration and functional recovery following thoracic and partial recovery after cervical spinal cord injury.

• Klíčová slova
• AAV vectors, Axon regeneration, Integrins, Kindlin, Sensory testing, Spinal cord injury,
• MeSH
• axony MeSH
• Dependovirus genetika   MeSH
• genetické vektory MeSH
• krysa rodu Rattus MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nervové receptory * metabolismus   fyziologie   patologie   MeSH
• obnova funkce fyziologie   MeSH
• poranění míchy * patologie   patofyziologie   metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• proteiny nervové tkáně metabolismus   genetika   MeSH
• regenerace nervu * fyziologie   MeSH
• tenascin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• proteiny nervové tkáně MeSH
• tenascin MeSH

Mammalian neurons lose the ability to regenerate their central nervous system axons as they mature during embryonic or early postnatal development. Neuronal maturation requires a transformation from a situation in which neuronal components grow and assemble to one in which these components are fixed and involved in the machinery for effective information transmission and computation. To regenerate after injury, neurons need to overcome this fixed state to reactivate their growth programme. A variety of intracellular processes involved in initiating or sustaining neuronal maturation, including the regulation of gene expression, cytoskeletal restructuring and shifts in intracellular trafficking, have been shown to prevent axon regeneration. Understanding these processes will contribute to the identification of targets to promote repair after injury or disease.

• MeSH
• axony * fyziologie   MeSH
• lidé MeSH
• neurogeneze * fyziologie   MeSH
• neurony fyziologie   MeSH
• regenerace nervu * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Adeno-associated viral vectors are widely used as vehicles for gene transfer to the nervous system. The promoter and viral vector serotype are two key factors that determine the expression dynamics of the transgene. A previous comparative study has demonstrated that AAV1 displays efficient transduction of layer V corticospinal neurons, but the optimal promoter for transgene expression in corticospinal neurons has not been determined yet. In this paper, we report a side-by-side comparison between four commonly used promoters: the short CMV early enhancer/chicken β actin (sCAG), human cytomegalovirus (hCMV), mouse phosphoglycerate kinase (mPGK) and human synapsin (hSYN) promoter. Reporter constructs with each of these promoters were packaged in AAV1, and were injected in the sensorimotor cortex of rats and mice in order to transduce the corticospinal tract. Transgene expression levels and the cellular transduction profile were examined after 6 weeks. The AAV1 vectors harbouring the hCMV and sCAG promoters resulted in transgene expression in neurons, astrocytes and oligodendrocytes. The mPGK and hSYN promoters directed the strongest transgene expression. The mPGK promoter did drive expression in cortical neurons and oligodendrocytes, while transduction with AAV harbouring the hSYN promoter resulted in neuron-specific expression, including perineuronal net expressing interneurons and layer V corticospinal neurons. This promoter comparison study contributes to improve transgene delivery into the brain and spinal cord. The optimized transduction of the corticospinal tract will be beneficial for spinal cord injury research.

• MeSH
• Dependovirus * genetika   MeSH
• genetické vektory genetika   MeSH
• krysa rodu Rattus MeSH
• myši MeSH
• promotorové oblasti (genetika) MeSH
• pyramidové dráhy * MeSH
• transdukce genetická MeSH
• transgeny MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Adult mammalian central nervous system axons have intrinsically poor regenerative capacity, so axonal injury has permanent consequences. One approach to enhancing regeneration is to increase the axonal supply of growth molecules and organelles. We achieved this by expressing the adaptor molecule Protrudin which is normally found at low levels in non-regenerative neurons. Elevated Protrudin expression enabled robust central nervous system regeneration both in vitro in primary cortical neurons and in vivo in the injured adult optic nerve. Protrudin overexpression facilitated the accumulation of endoplasmic reticulum, integrins and Rab11 endosomes in the distal axon, whilst removing Protrudin's endoplasmic reticulum localization, kinesin-binding or phosphoinositide-binding properties abrogated the regenerative effects. These results demonstrate that Protrudin promotes regeneration by functioning as a scaffold to link axonal organelles, motors and membranes, establishing important roles for these cellular components in mediating regeneration in the adult central nervous system.

• MeSH
• axony metabolismus   fyziologie   MeSH
• centrální nervový systém fyziologie   MeSH
• endoplazmatické retikulum genetika   metabolismus   MeSH
• endozomy metabolismus   MeSH
• fosforylace MeSH
• integriny metabolismus   MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• mutace MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• neurony metabolismus   fyziologie   MeSH
• neuroprotektivní látky aplikace a dávkování   MeSH
• poranění nervus opticus farmakoterapie   metabolismus   patologie   MeSH
• potkani Sprague-Dawley MeSH
• proteinové domény MeSH
• regenerace nervu * účinky léků   MeSH
• retina účinky léků   fyziologie   MeSH
• vezikulární transportní proteiny aplikace a dávkování   chemie   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• integriny MeSH
• neuroprotektivní látky MeSH
• vezikulární transportní proteiny MeSH
• ZFYVE27 protein, human MeSH Prohlížeč

Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3-kinase (PI3K) and its product phosphatidylinositol (3,4,5)-trisphosphate (PIP3 ). We demonstrate that adult PNS neurons utilise two catalytic subunits of PI3K for axon regeneration: p110α and p110δ. However, in the CNS, axonal PIP3 decreases with development at the time when axon transport declines and regenerative competence is lost. Overexpressing p110α in CNS neurons had no effect; however, expression of p110δ restored axonal PIP3 and increased regenerative axon transport. p110δ expression enhanced CNS regeneration in both rat and human neurons and in transgenic mice, functioning in the same way as the hyperactivating H1047R mutation of p110α. Furthermore, viral delivery of p110δ promoted robust regeneration after optic nerve injury. These findings establish a deficit of axonal PIP3 as a key reason for intrinsic regeneration failure and demonstrate that native p110δ facilitates axon regeneration by functioning in a hyperactive fashion.

• Klíčová slova
• CNS axon regeneration, axon transport, optic nerve, p110 delta, phosphoinositide 3-kinase,
• MeSH
• axony * MeSH
• centrální nervový systém MeSH
• dospělí MeSH
• fosfatidylinositol-3-kinasy * MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• myši MeSH
• neurony MeSH
• regenerace nervu MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Axon regeneration in the CNS is inhibited by many extrinsic and intrinsic factors. Because these act in parallel, no single intervention has been sufficient to enable full regeneration of damaged axons in the adult mammalian CNS. In the external environment, NogoA and CSPGs are strongly inhibitory to the regeneration of adult axons. CNS neurons lose intrinsic regenerative ability as they mature: embryonic but not mature neurons can grow axons for long distances when transplanted into the adult CNS, and regeneration fails with maturity in in vitro axotomy models. The causes of this loss of regeneration include partitioning of neurons into axonal and dendritic fields with many growth-related molecules directed specifically to dendrites and excluded from axons, changes in axonal signalling due to changes in expression and localization of receptors and their ligands, changes in local translation of proteins in axons, and changes in cytoskeletal dynamics after injury. Also with neuronal maturation come epigenetic changes in neurons, with many of the transcription factor binding sites that drive axon growth-related genes becoming inaccessible. The overall aim for successful regeneration is to ensure that the right molecules are expressed after axotomy and to arrange for them to be transported to the right place in the neuron, including the damaged axon tip.

• Klíčová slova
• Axon regeneration, Axonal transport, Chondroitin sulphate proteoglycans, Chondroitinase, Epigenetics, Integrins, NogoA, PTEN, Rabs, RhoA, Schwann cell, Signalling, Trafficking,
• MeSH
• axonální transport fyziologie   MeSH
• axony fyziologie   MeSH
• centrální nervový systém cytologie   fyziologie   MeSH
• lidé MeSH
• nervový útlum fyziologie   MeSH
• neurogeneze fyziologie   MeSH
• proteosyntéza fyziologie   MeSH
• regenerace nervu fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Integrins are cell surface receptors that form the link between extracellular matrix molecules of the cell environment and internal cell signalling and the cytoskeleton. They are involved in several processes, e.g. adhesion and migration during development and repair. This review focuses on the role of integrins in axonal regeneration. Integrins participate in spontaneous axonal regeneration in the peripheral nervous system through binding to various ligands that either inhibit or enhance their activation and signalling. Integrin biology is more complex in the central nervous system. Integrins receptors are transported into growing axons during development, but selective polarised transport of integrins limits the regenerative response in adult neurons. Manipulation of integrins and related molecules to control their activation state and localisation within axons is a promising route towards stimulating effective regeneration in the central nervous system.

• Klíčová slova
• axon regeneration, integrin, kindlin, receptor activation state, selective polarised transport, traumatic injury of the nervous system,
• MeSH
• axony fyziologie   MeSH
• integriny genetika   metabolismus   MeSH
• rány a poranění * MeSH
• regenerace nervu fyziologie   MeSH
• regulace genové exprese fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• integriny MeSH

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