INTRODUCTION: Spinal cord injury involves complex pathobiological mechanisms, necessitating a multidimensional approach for its cure. Previous studies have shown that α9-integrin expression and activation in mature dorsal root ganglion neurons enable the regeneration of injured axons within the spinal cord. However, tissue cavitation and fibrosis impede the regenerating axons from following their usual pathways, forcing them to seek alternative routes rich in tenascin-C, the primary ligand of the integrin. Fibrin gel, an FDA-approved and biocompatible material, can offer three-dimensional support for axonal extension through the cavitated area, thus preventing the formation of aberrant paths and connections that occur in the absence of a suitable scaffold. METHODS: The aim of this study was to investigate how combining α9-integrin expression by adeno-associated virus with the use of a fibrin gel as an extracellular microenvironment affects the growth of mature DRG neurites in vitro. Additionally, we sought to functionalize fibrin with integrin ligand peptides, specifically AEIDGIEL, the active domain of tenascin-C, to ensure α9-integrin activation. RESULTS: Our results indicate that fibrin gels are a suitable biomaterial for promoting neurite growth and that AEIDGIEL peptide effectively activates the integrin. Furthermore, we corroborate an autocrine signaling loop of α9-integrin and TN-C produced by neurons. DISCUSSION: the proposed combination therapy of α9-integrin and fibrin gel biomaterials incorporating AEIDGIEL peptide shows promise for addressing the complex challenges of spinal cord injury and promoting effective neural regeneration, laying the foundation for further in vivo research.

• Keywords
• AEIDGIEL peptide, biomaterials, dorsal root ganglion, fibrin gel, neurite growth, spinal cord injury, tenascin-c, α9-integrin,
• Publication type
• Journal Article 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
• Axons * physiology   MeSH
• Humans MeSH
• Neurogenesis * physiology   MeSH
• Neurons physiology   MeSH
• Nerve Regeneration * physiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Spinal cord interneurons (SpINs) are highly diverse population of neurons that play a significant role in circuit reorganization and spontaneous recovery after spinal cord injury. Regeneration of SpIN axons across rodent spinal injuries has been demonstrated after modification of the environment and neurotrophin treatment, but development of methods to enhance the intrinsic regenerative ability of SpINs is needed. There is a lack of described in vitro models of spinal cord neurons in which to develop new regeneration treatments. For this reason, we developed a new model of mouse primary spinal cord neuronal culture in which to analyze maturation, morphology, physiology, connectivity and regeneration of identified interneurons. Isolated from E14 mice, the neurons mature over 15 days in vitro, demonstrated by expression of maturity markers, electrophysiological patch-clamp recordings, and formation of synapses. The neurons express markers of SpINs, including Tlx3, Lmx1b, Lbx1, Chx10, and Pax2. The neurons demonstrate distinct morphologies and some form perineuronal nets in long-term cultivation. Live neurons in various maturation stages were axotomized, using a 900 nm multiphoton laser and their fate was observed overnight. The percentage of axons that regenerated declined with neuronal maturity. This model of SpINs will be a valuable tool in future regenerative, developmental, and functional studies alongside existing models using cortical or hippocampal neurons.

• Keywords
• axon regeneration, culture, laser axotomy, maturation, spinal interneurons,
• Publication type
• Journal Article 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
• Axons metabolism   physiology   MeSH
• Central Nervous System physiology   MeSH
• Endoplasmic Reticulum genetics   metabolism   MeSH
• Endosomes metabolism   MeSH
• Phosphorylation MeSH
• Integrins metabolism   MeSH
• Rats MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Mutation MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Neurons metabolism   physiology   MeSH
• Neuroprotective Agents administration & dosage   MeSH
• Optic Nerve Injuries drug therapy   metabolism   pathology   MeSH
• Rats, Sprague-Dawley MeSH
• Protein Domains MeSH
• Nerve Regeneration * drug effects   MeSH
• Retina drug effects   physiology   MeSH
• Vesicular Transport Proteins administration & dosage   chemistry   genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Humans MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Intramural MeSH
• Names of Substances
• Integrins MeSH
• Neuroprotective Agents MeSH
• Vesicular Transport Proteins MeSH
• ZFYVE27 protein, human MeSH Browser