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Fornaro M, Dipollina C, Giambalvo D, Garcia R, Sigerson C, Sharthiya H, Liu C, Nealey PF, Kristjansdottir K, Gasiorowski JZ. Submicron Topographically Patterned 3D Substrates Enhance Directional Axon Outgrowth of Dorsal Root Ganglia Cultured Ex Vivo. Biomolecules 2022; 12:biom12081059. [PMID: 36008953 PMCID: PMC9405616 DOI: 10.3390/biom12081059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 11/26/2022] Open
Abstract
A peripheral nerve injury results in disruption of the fiber that usually protects axons from the surrounding environment. Severed axons from the proximal nerve stump are capable of regenerating, but axons are exposed to a completely new environment. Regeneration recruits cells that produce and deposit key molecules, including growth factor proteins and fibrils in the extracellular matrix (ECM), thus changing the chemical and geometrical environment. The regenerating axons thus surf on a newly remodeled micro-landscape. Strategies to enhance and control axonal regeneration and growth after injury often involve mimicking the extrinsic cues that are found in the natural nerve environment. Indeed, nano- and micropatterned substrates have been generated as tools to guide axons along a defined path. The mechanical cues of the substrate are used as guides to orient growth or change the direction of growth in response to impediments or cell surface topography. However, exactly how axons respond to biophysical information and the dynamics of axonal movement are still poorly understood. Here we use anisotropic, groove-patterned substrate topography to direct and enhance sensory axonal growth of whole mouse dorsal root ganglia (DRG) transplanted ex vivo. Our results show significantly enhanced and directed growth of the DRG sensory fibers on the hemi-3D topographic substrates compared to a 0 nm pitch, flat control surface. By assessing the dynamics of axonal movement in time-lapse microscopy, we found that the enhancement was not due to increases in the speed of axonal growth, but to the efficiency of growth direction, ensuring axons minimize movement in undesired directions. Finally, the directionality of growth was reproduced on topographic patterns fabricated as fully 3D substrates, potentially opening new translational avenues of development incorporating these specific topographic feature sizes in implantable conduits in vivo.
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Affiliation(s)
- Michele Fornaro
- Department of Anatomy, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA;
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (C.D.); (D.G.); (C.S.)
- Correspondence: (M.F.); (J.Z.G.)
| | - Christopher Dipollina
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (C.D.); (D.G.); (C.S.)
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (R.G.); (K.K.)
| | - Darryl Giambalvo
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (C.D.); (D.G.); (C.S.)
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (R.G.); (K.K.)
| | - Robert Garcia
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (R.G.); (K.K.)
| | - Casey Sigerson
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (C.D.); (D.G.); (C.S.)
| | - Harsh Sharthiya
- Department of Anatomy, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA;
| | - Claire Liu
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA; (C.L.); (P.F.N.)
| | - Paul F. Nealey
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA; (C.L.); (P.F.N.)
| | - Kolbrun Kristjansdottir
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (R.G.); (K.K.)
| | - Joshua Z. Gasiorowski
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (R.G.); (K.K.)
- Correspondence: (M.F.); (J.Z.G.)
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Patel M, Ahn S, Koh WG. Topographical pattern for neuronal tissue engineering. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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The Role of Tissue Geometry in Spinal Cord Regeneration. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58040542. [PMID: 35454380 PMCID: PMC9028021 DOI: 10.3390/medicina58040542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022]
Abstract
Unlike peripheral nerves, axonal regeneration is limited following injury to the spinal cord. While there may be reduced regenerative potential of injured neurons, the central nervous system (CNS) white matter environment appears to be more significant in limiting regrowth. Several factors may inhibit regeneration, and their neutralization can modestly enhance regrowth. However, most investigations have not considered the cytoarchitecture of spinal cord white matter. Several lines of investigation demonstrate that axonal regeneration is enhanced by maintaining, repairing, or reconstituting the parallel geometry of the spinal cord white matter. In this review, we focus on environmental factors that have been implicated as putative inhibitors of axonal regeneration and the evidence that their organization may be an important determinant in whether they inhibit or promote regeneration. Consideration of tissue geometry may be important for developing successful strategies to promote spinal cord regeneration.
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