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Amar Kumar P, Dulin JN. Implications of regional identity for neural stem and progenitor cell transplantation in the injured or diseased nervous system. Neural Regen Res 2024; 19:715-716. [PMID: 37843199 PMCID: PMC10664136 DOI: 10.4103/1673-5374.382236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/08/2023] [Accepted: 06/29/2023] [Indexed: 10/17/2023] Open
Affiliation(s)
| | - Jennifer N. Dulin
- Department of Biology, Texas A&M University, College Station, TX, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, USA
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2
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Tigner TJ, Dampf G, Tucker A, Huang YC, Jagrit V, Clevenger AJ, Mohapatra A, Raghavan SA, Dulin JN, Alge DL. Clickable Granular Hydrogel Scaffolds for Delivery of Neural Progenitor Cells to Sites of Spinal Cord Injury. Adv Healthc Mater 2024:e2303912. [PMID: 38470994 DOI: 10.1002/adhm.202303912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/27/2024] [Indexed: 03/14/2024]
Abstract
Spinal cord injury (SCI) is a serious condition with limited treatment options. Neural progenitor cell (NPC) transplantation is a promising treatment option, and the identification of novel biomaterial scaffolds that support NPC engraftment and therapeutic activity is a top research priority. The objective of this study is to evaluate in situ assembled poly (ethylene glycol) (PEG)-based granular hydrogels for NPC delivery in a murine model of SCI. Microgel precursors are synthesized by using thiol-norbornene click chemistry to react four-armed PEG-amide-norbornene with enzymatically degradable and cell adhesive peptides. Unreacted norbornene groups are utilized for in situ assembly into scaffolds using a PEG-di-tetrazine linker. The granular hydrogel scaffolds exhibit good biocompatibility and do not adversely affect the inflammatory response after SCI. Moreover, when used to deliver NPCs, the granular hydrogel scaffolds supported NPC engraftment, do not adversely affect the immune response to the NPC grafts, and successfully support graft differentiation toward neuronal or astrocytic lineages as well as axonal extension into the host tissue. Collectively, these data establish PEG-based granular hydrogel scaffolds as a suitable biomaterial platform for NPC delivery and justify further testing, particularly in the context of more severe SCI.
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Affiliation(s)
- Thomas J Tigner
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Gabrielle Dampf
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Ashley Tucker
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Yu-Chi Huang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Vipin Jagrit
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Abigail J Clevenger
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Arpita Mohapatra
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Shreya A Raghavan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843-3474, USA
| | - Daniel L Alge
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
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3
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Jagrit V, Koffler J, Dulin JN. Combinatorial strategies for cell transplantation in traumatic spinal cord injury. Front Neurosci 2024; 18:1349446. [PMID: 38510468 PMCID: PMC10951004 DOI: 10.3389/fnins.2024.1349446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/20/2024] [Indexed: 03/22/2024] Open
Abstract
Spinal cord injury (SCI) substantially reduces the quality of life of affected individuals. Recovery of function is therefore a primary concern of the patient population and a primary goal for therapeutic interventions. Currently, even with growing numbers of clinical trials, there are still no effective treatments that can improve neurological outcomes after SCI. A large body of work has demonstrated that transplantation of neural stem/progenitor cells (NSPCs) can promote regeneration of the injured spinal cord by providing new neurons that can integrate into injured host neural circuitry. Despite these promising findings, the degree of functional recovery observed after NSPC transplantation remains modest. It is evident that treatment of such a complex injury cannot be addressed with a single therapeutic approach. In this mini-review, we discuss combinatorial strategies that can be used along with NSPC transplantation to promote spinal cord regeneration. We begin by introducing bioengineering and neuromodulatory approaches, and highlight promising work using these strategies in integration with NSPCs transplantation. The future of NSPC transplantation will likely include a multi-factorial approach, combining stem cells with biomaterials and/or neuromodulation as a promising treatment for SCI.
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Affiliation(s)
- Vipin Jagrit
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Jacob Koffler
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
- Veterans Affairs Medical Center, San Diego, CA, United States
| | - Jennifer N. Dulin
- Department of Biology, Texas A&M University, College Station, TX, United States
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
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4
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Baltazar A, Tucker A, Jang J, Vo K, Dulin JN. Differences in Anatomical Outcomes Between Early Chronic and Far Chronic Time-Points After Transplantation of Spinal Cord Neural Progenitor Cells in Mice. J Neurotrauma 2023; 40:2487-2499. [PMID: 37597207 PMCID: PMC10698786 DOI: 10.1089/neu.2023.0264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2023] Open
Abstract
Spinal cord injury (SCI) affects millions of people worldwide. Neural progenitor cell (NPC) transplantation is a promising treatment for regenerating lost spinal cord tissue and restoring neurological function after SCI. We conducted a literature search and found that less than a quarter of experimental rodent cell and tissue transplantation studies have investigated anatomical outcomes at longer than 4 months post-transplantation. This is a critical topic to investigate, given that stem and progenitor cell therapies would need to remain in place throughout the lifetime of an individual. We sought to determine how commonly assessed anatomical outcomes evolve between early and far chronic time-points post-NPC transplantation. At either 8 weeks or 26 weeks following transplantation of NPCs into sites of cervical SCI, we evaluated graft neuronal density, astroglial cell density, graft axon outgrowth, and regeneration of host axon populations into grafts in male and female mice. We found that graft neuronal density does not change over time, but the numbers of graft-associated astrocytes and glial fibrillary acidic protein intensity is significantly increased in the far chronic phase compared with the early chronic time-point. In addition, graft axon outgrowth was significantly decreased at 26 weeks post-transplantation compared with 8 weeks post-transplantation. In contrast, corticospinal axon regeneration into grafts was not diminished over time, but rather increased significantly from early to far chronic periods. Interestingly, we found that graft neuronal density is significantly influenced by sex of the host animal, suggesting that sex-dependent processes may shape graft composition over time. Collectively, these results demonstrate that NPC transplants are dynamic and that commonly assessed outcome measures associated with graft efficacy evolve over the weeks to months post-transplantation into the spinal cord.
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Affiliation(s)
- Angelina Baltazar
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA
| | - Ashley Tucker
- Department of Biology, Texas A&M University, College Station, Texas, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, Texas, USA
| | - Julius Jang
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Katie Vo
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Jennifer N. Dulin
- Department of Biology, Texas A&M University, College Station, Texas, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, Texas, USA
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5
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Aceves M, Tucker A, Chen J, Vo K, Moses J, Amar Kumar P, Thomas H, Miranda D, Dampf G, Dietz V, Chang M, Lukose A, Jang J, Nadella S, Gillespie T, Trevino C, Buxton A, Pritchard AL, Green P, McCreedy DA, Dulin JN. Publisher Correction: Developmental stage of transplanted neural progenitor cells influences anatomical and functional outcomes after spinal cord injury in mice. Commun Biol 2023; 6:635. [PMID: 37311793 PMCID: PMC10264442 DOI: 10.1038/s42003-023-05018-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023] Open
Affiliation(s)
- Miriam Aceves
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Ashley Tucker
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Joseph Chen
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Katie Vo
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Joshua Moses
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | | | - Hannah Thomas
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Diego Miranda
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Gabrielle Dampf
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Valerie Dietz
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Matthew Chang
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Aleena Lukose
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Julius Jang
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Sneha Nadella
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Tucker Gillespie
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Christian Trevino
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Andrew Buxton
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Anna L Pritchard
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | | | - Dylan A McCreedy
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA.
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6
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Aceves M, Tucker A, Chen J, Vo K, Moses J, Amar Kumar P, Thomas H, Miranda D, Dampf G, Dietz V, Chang M, Lukose A, Jang J, Nadella S, Gillespie T, Trevino C, Buxton A, Pritchard AL, Green P, McCreedy DA, Dulin JN. Developmental stage of transplanted neural progenitor cells influences anatomical and functional outcomes after spinal cord injury in mice. Commun Biol 2023; 6:544. [PMID: 37208439 PMCID: PMC10199026 DOI: 10.1038/s42003-023-04893-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/02/2023] [Indexed: 05/21/2023] Open
Abstract
Neural progenitor cell (NPC) transplantation is a promising therapeutic strategy for replacing lost neurons following spinal cord injury (SCI). However, how graft cellular composition influences regeneration and synaptogenesis of host axon populations, or recovery of motor and sensory functions after SCI, is poorly understood. We transplanted developmentally-restricted spinal cord NPCs, isolated from E11.5-E13.5 mouse embryos, into sites of adult mouse SCI and analyzed graft axon outgrowth, cellular composition, host axon regeneration, and behavior. Earlier-stage grafts exhibited greater axon outgrowth, enrichment for ventral spinal cord interneurons and Group-Z spinal interneurons, and enhanced host 5-HT+ axon regeneration. Later-stage grafts were enriched for late-born dorsal horn interneuronal subtypes and Group-N spinal interneurons, supported more extensive host CGRP+ axon ingrowth, and exacerbated thermal hypersensitivity. Locomotor function was not affected by any type of NPC graft. These findings showcase the role of spinal cord graft cellular composition in determining anatomical and functional outcomes following SCI.
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Affiliation(s)
- Miriam Aceves
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Ashley Tucker
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Joseph Chen
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Katie Vo
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Joshua Moses
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | | | - Hannah Thomas
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Diego Miranda
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Gabrielle Dampf
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Valerie Dietz
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Matthew Chang
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Aleena Lukose
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Julius Jang
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Sneha Nadella
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Tucker Gillespie
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Christian Trevino
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Andrew Buxton
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Anna L Pritchard
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | | | - Dylan A McCreedy
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843, USA.
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7
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Kjell J, Dulin JN, Warren PM. Editorial: Fighting for recovery on multiple fronts in spinal cord injury. Front Cell Neurosci 2023; 17:1178192. [PMID: 36998266 PMCID: PMC10043413 DOI: 10.3389/fncel.2023.1178192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/18/2023] Open
Affiliation(s)
- Jacob Kjell
- Department of Clinical Neuroscience, Karolinska Institutet (KI), Stockholm, Sweden
| | - Jennifer N. Dulin
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
- Department of Biology, College of Science, Texas A&M University College Station, College Station, TX, United States
| | - Philippa M. Warren
- Wolfson Centre for Age-Related Diseases, School of Neuroscience, King's College London, London, United Kingdom
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8
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Tucker A, Dulin JN. The Emerging Role of Biological Sex in Cell Therapy for Spinal Cord Injury. Neurosci Insights 2023; 18:26331055231153128. [PMID: 36798608 PMCID: PMC9925999 DOI: 10.1177/26331055231153128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 02/13/2023] Open
Abstract
Neural progenitor cell (NPC) transplantation is a promising potential therapy for replacing spinal cord neurons and glial cells following spinal cord injury (SCI). Despite the rapid advancement of NPC transplantation to SCI clinical trials, we still lack understanding of fundamental biology underlying how NPC grafts interact with the injured host nervous system. Our recent study demonstrated a potent effect of biological sex mismatch between donor and host on graft immune rejection. Here we discuss the implications of this study in the context of clinical trials for SCI, and important topics for future research in SCI cell transplantation.
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Affiliation(s)
- Ashley Tucker
- Department of Biology, Texas A&M
University, College Station, TX, USA
- Texas A&M Institute for
Neuroscience, Texas A&M University, College Station, TX, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M
University, College Station, TX, USA
- Texas A&M Institute for
Neuroscience, Texas A&M University, College Station, TX, USA
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9
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Alfieri JM, Jonika MM, Dulin JN, Blackmon H. Tempo and Mode of Genome Structure Evolution in Insects. Genes (Basel) 2023; 14:336. [PMID: 36833264 PMCID: PMC9957073 DOI: 10.3390/genes14020336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
The division of the genome into discrete chromosomes is a fundamental characteristic of eukaryotic life. Insect taxonomists' early adoption of cytogenetics has led to an incredible amount of data describing genome structure across insects. In this article, we synthesize data from thousands of species and use biologically realistic models to infer the tempo and mode of chromosome evolution among insect orders. Our results show that orders vary dramatically in the overall rate of chromosome number evolution (a proxy of genome structural stability) and the pattern of evolution (e.g., the balance between fusions and fissions). These findings have important implications for our understanding of likely modes of speciation and offer insight into the most informative clades for future genome sequencing.
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Affiliation(s)
- James M. Alfieri
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- Interdisciplinary Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA
| | - Michelle M. Jonika
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, USA
| | - Jennifer N. Dulin
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- Interdisciplinary Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, USA
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10
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Pitonak M, Aceves M, Kumar PA, Dampf G, Green P, Tucker A, Dietz V, Miranda D, Letchuman S, Jonika MM, Bautista D, Blackmon H, Dulin JN. Effects of biological sex mismatch on neural progenitor cell transplantation for spinal cord injury in mice. Nat Commun 2022; 13:5380. [PMID: 36104357 PMCID: PMC9474813 DOI: 10.1038/s41467-022-33134-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/02/2022] [Indexed: 12/03/2022] Open
Abstract
Despite advancement of neural progenitor cell transplantation to spinal cord injury clinical trials, there remains a lack of understanding of how biological sex of transplanted cells influences outcomes after transplantation. To address this, we transplanted GFP-expressing sex-matched, sex-mismatched, or mixed donor cells into sites of spinal cord injury in adult male and female mice. Biological sex of the donor cells does not influence graft neuron density, glial differentiation, formation of the reactive glial cell border, or graft axon outgrowth. However, male grafts in female hosts feature extensive hypervascularization accompanied by increased vascular diameter and perivascular cell density. We show greater T-cell infiltration within male-to-female grafts than other graft types. Together, these findings indicate a biological sex-specific immune response of female mice to male donor cells. Our work suggests that biological sex should be considered in the design of future clinical trials for cell transplantation in human injury. In this study, Pitonak et al. report that transplantation of neural progenitor cells derived from male donors trigger an immune rejection response following transplantation into sites of spinal cord injury in female mice.
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11
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Dietz VA, Roberts N, Knox K, Moore S, Pitonak M, Barr C, Centeno J, Leininger S, New KC, Nowell P, Rodreick M, Geoffroy CG, Stampas A, Dulin JN. Fighting for recovery on multiple fronts: The past, present, and future of clinical trials for spinal cord injury. Front Cell Neurosci 2022; 16:977679. [PMID: 36212690 PMCID: PMC9533868 DOI: 10.3389/fncel.2022.977679] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 11/16/2022] Open
Abstract
Through many decades of preclinical research, great progress has been achieved in understanding the complex nature of spinal cord injury (SCI). Preclinical research efforts have guided and shaped clinical trials, which are growing in number by the year. Currently, 1,149 clinical trials focused on improving outcomes after SCI are registered in the U.S. National Library of Medicine at ClinicalTrials.gov. We conducted a systematic analysis of these SCI clinical trials, using publicly accessible data downloaded from ClinicalTrials.gov. After extracting all available data for these trials, we categorized each trial according to the types of interventions being tested and the types of outcomes assessed. We then evaluated clinical trial characteristics, both globally and by year, in order to understand the areas of growth and change over time. With regard to clinical trial attributes, we found that most trials have low enrollment, only test single interventions, and have limited numbers of primary outcomes. Some gaps in reporting are apparent; for instance, over 75% of clinical trials with "Completed" status do not have results posted, and the Phase of some trials is incorrectly classified as "Not applicable" despite testing a drug or biological compound. When analyzing trials based on types of interventions assessed, we identified the largest representation in trials testing rehab/training/exercise, neuromodulation, and behavioral modifications. Most highly represented primary outcomes include motor function of the upper and lower extremities, safety, and pain. The most highly represented secondary outcomes include quality of life and pain. Over the past 15 years, we identified increased representation of neuromodulation and rehabilitation trials, and decreased representation of drug trials. Overall, the number of new clinical trials initiated each year continues to grow, signifying a hopeful future for the clinical treatment of SCI. Together, our work provides a comprehensive glimpse into the past, present, and future of SCI clinical trials, and suggests areas for improvement in clinical trial reporting.
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Affiliation(s)
- Valerie A. Dietz
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Nolan Roberts
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Katelyn Knox
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Sherilynne Moore
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Michael Pitonak
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Chris Barr
- Unite 2 Fight Paralysis, Minneapolis, MN, United States
| | - Jesus Centeno
- Unite 2 Fight Paralysis, Minneapolis, MN, United States
| | | | - Kent C. New
- Unite 2 Fight Paralysis, Minneapolis, MN, United States
| | - Peter Nowell
- Unite 2 Fight Paralysis, Minneapolis, MN, United States
| | | | - Cedric G. Geoffroy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University, College Station, TX, United States
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Argyrios Stampas
- Department of Physical Medicine and Rehabilitation, UTHealth Houston McGovern Medical School, Houston, TX, United States
| | - Jennifer N. Dulin
- Department of Biology, Texas A&M University, College Station, TX, United States
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
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12
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Dietz V, Knox K, Moore S, Roberts N, Corona KK, Dulin JN. Dorsal horn neuronal sparing predicts the development of at-level mechanical allodynia following cervical spinal cord injury in mice. Exp Neurol 2022; 352:114048. [PMID: 35304102 DOI: 10.1016/j.expneurol.2022.114048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/03/2022] [Accepted: 03/13/2022] [Indexed: 11/04/2022]
Abstract
Spinal cord injury (SCI) frequently results in immediate and sustained neurological dysfunction, including intractable neuropathic pain in approximately 60-80% of individuals. SCI induces immediate mechanical damage to spinal cord tissue followed by a period of secondary injury in which tissue damage is further propagated, contributing to the development of anatomically unique lesions. Variability in lesion size and location influences the degree of motor and sensory dysfunction incurred by an individual. We predicted that variability in lesion parameters may also explain why some, but not all, experimental animals develop mechanical sensitivity after SCI. To characterize the relationship of lesion anatomy to mechanical allodynia, we utilized a mouse cervical hemicontusion model of SCI that has been shown to lead to the development and persistence of mechanical allodynia in the ipsilateral forelimb after injury. At four weeks post-SCI, the numbers and locations of surviving neurons were quantified along with total lesion volume and nociceptive fiber sprouting. We found that the subset of animals exhibiting mechanical allodynia had significantly increased neuronal sparing in the ipsilateral dorsal horn around the lesion epicenter compared to animals that did not exhibit mechanical allodynia. Additionally, we failed to observe significant differences between groups in nociceptive fiber density in the dorsal horn around the lesion epicenter. Notably, we found that impactor probe displacement upon administration of the SCI surgery was significantly lower in sensitive animals compared with not-sensitive animals. Together, our data indicate that lesion severity negatively correlates with the manifestation of at-level mechanical hypersensitivity and suggests that sparing of dorsal horn neurons may be required for the development of neuropathic pain.
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Affiliation(s)
- Valerie Dietz
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Katelyn Knox
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Sherilynne Moore
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Nolan Roberts
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | | | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA.
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13
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Abstract
Spinal cord injury remains a scientific and therapeutic challenge with great cost to individuals and society. The goal of research in this field is to find a means of restoring lost function. Recently we have seen considerable progress in understanding the injury process and the capacity of CNS neurons to regenerate, as well as innovations in stem cell biology. This presents an opportunity to develop effective transplantation strategies to provide new neural cells to promote the formation of new neuronal networks and functional connectivity. Past and ongoing clinical studies have demonstrated the safety of cell therapy, and preclinical research has used models of spinal cord injury to better elucidate the underlying mechanisms through which donor cells interact with the host and thus increase long-term efficacy. While a variety of cell therapies have been explored, we focus here on the use of neural progenitor cells obtained or derived from different sources to promote connectivity in sensory, motor and autonomic systems.
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Affiliation(s)
- Itzhak Fischer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA.
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
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14
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Koffler J, Zhu W, Qu X, Platoshyn O, Dulin JN, Brock J, Graham L, Lu P, Sakamoto J, Marsala M, Chen S, Tuszynski MH. Biomimetic 3D-printed scaffolds for spinal cord injury repair. Nat Med 2019; 25:263-269. [PMID: 30643285 DOI: 10.1038/s41591-018-0296-z] [Citation(s) in RCA: 328] [Impact Index Per Article: 65.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 11/08/2018] [Indexed: 12/22/2022]
Abstract
Current methods for bioprinting functional tissue lack appropriate biofabrication techniques to build complex 3D microarchitectures essential for guiding cell growth and promoting tissue maturation1. 3D printing of central nervous system (CNS) structures has not been accomplished, possibly owing to the complexity of CNS architecture. Here, we report the use of a microscale continuous projection printing method (μCPP) to create a complex CNS structure for regenerative medicine applications in the spinal cord. μCPP can print 3D biomimetic hydrogel scaffolds tailored to the dimensions of the rodent spinal cord in 1.6 s and is scalable to human spinal cord sizes and lesion geometries. We tested the ability of µCPP 3D-printed scaffolds loaded with neural progenitor cells (NPCs) to support axon regeneration and form new 'neural relays' across sites of complete spinal cord injury in vivo in rodents1,2. We find that injured host axons regenerate into 3D biomimetic scaffolds and synapse onto NPCs implanted into the device and that implanted NPCs in turn extend axons out of the scaffold and into the host spinal cord below the injury to restore synaptic transmission and significantly improve functional outcomes. Thus, 3D biomimetic scaffolds offer a means of enhancing CNS regeneration through precision medicine.
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Affiliation(s)
- Jacob Koffler
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA.
| | - Wei Zhu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Xin Qu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Oleksandr Platoshyn
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, USA
| | - Jennifer N Dulin
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA
| | - John Brock
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA
| | - Lori Graham
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA
| | - Paul Lu
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA
| | - Jeff Sakamoto
- Mechanical Engineering Department, University of Michigan, Ann Arbor, MI, USA
| | - Martin Marsala
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, USA
| | - Shaochen Chen
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA.
| | - Mark H Tuszynski
- Department of Neuroscience, University of California San Diego, La Jolla, CA, USA. .,Veterans Affairs Medical Center, San Diego, CA, USA.
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15
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Abstract
The mapping of long-range axonal projections is a rapidly growing endeavor in the field of neuroscience. Recent advances in the development of adeno-associated viral vectors that can achieve efficient retrograde transport now enable the characterization and manipulation of specific neuronal subpopulations using Cre-dependent, intersectional approaches. Importantly, these approaches can be applied to non-transgenic animals, making it possible to carry out detailed anatomical studies across a variety of species including nonhuman primates. In this chapter, we demonstrate the utility of such intersectional strategies by describing methods for targeting viral constructs to distinct subsets of corticospinal motor neurons based on their projections to specific spinal cord segments.
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Affiliation(s)
- James M Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Greg L Bain
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, USA.
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16
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Poplawski GHD, Lie R, Hunt M, Kumamaru H, Kawaguchi R, Lu P, Schäfer MKE, Woodruff G, Robinson J, Canete P, Dulin JN, Geoffroy CG, Menzel L, Zheng B, Coppola G, Tuszynski MH. Adult rat myelin enhances axonal outgrowth from neural stem cells. Sci Transl Med 2018; 10:eaal2563. [PMID: 29794059 PMCID: PMC8377986 DOI: 10.1126/scitranslmed.aal2563] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 06/07/2017] [Accepted: 11/17/2017] [Indexed: 12/18/2022]
Abstract
Axon regeneration after spinal cord injury (SCI) is attenuated by growth inhibitory molecules associated with myelin. We report that rat myelin stimulated the growth of axons emerging from rat neural progenitor cells (NPCs) transplanted into sites of SCI in adult rat recipients. When plated on a myelin substrate, neurite outgrowth from rat NPCs and from human induced pluripotent stem cell (iPSC)-derived neural stem cells (NSCs) was enhanced threefold. In vivo, rat NPCs and human iPSC-derived NSCs extended greater numbers of axons through adult central nervous system white matter than through gray matter and preferentially associated with rat host myelin. Mechanistic investigations excluded Nogo receptor signaling as a mediator of stem cell-derived axon growth in response to myelin. Transcriptomic screens of rodent NPCs identified the cell adhesion molecule neuronal growth regulator 1 (Negr1) as one mediator of permissive axon-myelin interactions. The stimulatory effect of myelin-associated proteins on rodent NPCs was developmentally regulated and involved direct activation of the extracellular signal-regulated kinase (ERK). The stimulatory effects of myelin on NPC/NSC axon outgrowth should be investigated further and could potentially be exploited for neural repair after SCI.
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Affiliation(s)
- Gunnar H D Poplawski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard Lie
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Matt Hunt
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Riki Kawaguchi
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
- Veterans Administration Medical Center, San Diego, CA 92161, USA
| | - Michael K E Schäfer
- Department of Anesthesiology and Focus Program Translational Neurosciences, Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Grace Woodruff
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacob Robinson
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Philip Canete
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cedric G Geoffroy
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lutz Menzel
- Department of Anesthesiology and Focus Program Translational Neurosciences, Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Binhai Zheng
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Giovanni Coppola
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA.
- Veterans Administration Medical Center, San Diego, CA 92161, USA
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17
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Dulin JN, Adler AF, Kumamaru H, Poplawski GHD, Lee-Kubli C, Strobl H, Gibbs D, Kadoya K, Fawcett JW, Lu P, Tuszynski MH. Injured adult motor and sensory axons regenerate into appropriate organotypic domains of neural progenitor grafts. Nat Commun 2018; 9:84. [PMID: 29311559 PMCID: PMC5758751 DOI: 10.1038/s41467-017-02613-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/14/2017] [Indexed: 02/02/2023] Open
Abstract
Neural progenitor cell (NPC) transplantation has high therapeutic potential in neurological disorders. Functional restoration may depend on the formation of reciprocal connections between host and graft. While it has been reported that axons extending out of neural grafts in the brain form contacts onto phenotypically appropriate host target regions, it is not known whether adult, injured host axons regenerating into NPC grafts also form appropriate connections. We report that spinal cord NPCs grafted into the injured adult rat spinal cord self-assemble organotypic, dorsal horn-like domains. These clusters are extensively innervated by regenerating adult host sensory axons and are avoided by corticospinal axons. Moreover, host axon regeneration into grafts increases significantly after enrichment with appropriate neuronal targets. Together, these findings demonstrate that injured adult axons retain the ability to recognize appropriate targets and avoid inappropriate targets within neural progenitor grafts, suggesting that restoration of complex circuitry after SCI may be achievable.
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Affiliation(s)
- Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Andrew F Adler
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Gunnar H D Poplawski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Corinne Lee-Kubli
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hans Strobl
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Daniel Gibbs
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ken Kadoya
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Orthopaedic Surgery, Hokkaido University, Sapporo, 060-8638, Japan
| | - James W Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0SP, UK
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Veterans Administration Medical Center, San Diego, CA, 92161, USA
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA.
- Veterans Administration Medical Center, San Diego, CA, 92161, USA.
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18
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Rocca CJ, Goodman SM, Dulin JN, Haquang JH, Gertsman I, Blondelle J, Smith JLM, Heyser CJ, Cherqui S. Transplantation of wild-type mouse hematopoietic stem and progenitor cells ameliorates deficits in a mouse model of Friedreich's ataxia. Sci Transl Med 2017; 9:eaaj2347. [PMID: 29070698 PMCID: PMC5735830 DOI: 10.1126/scitranslmed.aaj2347] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 01/31/2017] [Accepted: 06/13/2017] [Indexed: 12/14/2022]
Abstract
Friedreich's ataxia (FRDA) is an incurable autosomal recessive neurodegenerative disease caused by reduced expression of the mitochondrial protein frataxin due to an intronic GAA-repeat expansion in the FXN gene. We report the therapeutic efficacy of transplanting wild-type mouse hematopoietic stem and progenitor cells (HSPCs) into the YG8R mouse model of FRDA. In the HSPC-transplanted YG8R mice, development of muscle weakness and locomotor deficits was abrogated as was degeneration of large sensory neurons in the dorsal root ganglia (DRGs) and mitochondrial capacity was improved in brain, skeletal muscle, and heart. Transplanted HSPCs engrafted and then differentiated into microglia in the brain and spinal cord and into macrophages in the DRGs, heart, and muscle of YG8R FRDA mice. We observed the transfer of wild-type frataxin and Cox8 mitochondrial proteins from HSPC-derived microglia/macrophages to FRDA mouse neurons and muscle myocytes in vivo. Our results show the HSPC-mediated phenotypic rescue of FRDA in YG8R mice and suggest that this approach should be investigated further as a strategy for treating FRDA.
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Affiliation(s)
- Celine J Rocca
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Spencer M Goodman
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joseph H Haquang
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ilya Gertsman
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jordan Blondelle
- Division of Cardiovascular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Janell L M Smith
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Charles J Heyser
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stephanie Cherqui
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.
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19
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Kadoya K, Lu P, Nguyen K, Lee-Kubli C, Kumamaru H, Yao L, Knackert J, Poplawski G, Dulin JN, Strobl H, Takashima Y, Biane J, Conner J, Zhang SC, Tuszynski MH. Spinal cord reconstitution with homologous neural grafts enables robust corticospinal regeneration. Nat Med 2016; 22:479-87. [PMID: 27019328 PMCID: PMC4860037 DOI: 10.1038/nm.4066] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 02/12/2016] [Indexed: 02/07/2023]
Abstract
The corticospinal tract (CST) is the most important motor system in humans, yet robust regeneration of this projection after spinal cord injury (SCI) has not been accomplished. In murine models of SCI, we report robust corticospinal axon regeneration, functional synapse formation and improved skilled forelimb function after grafting multipotent neural progenitor cells into sites of SCI. Corticospinal regeneration requires grafts to be driven toward caudalized (spinal cord), rather than rostralized, fates. Fully mature caudalized neural grafts also support corticospinal regeneration. Moreover, corticospinal axons can emerge from neural grafts and regenerate beyond the lesion, a process that is potentially related to the attenuation of the glial scar. Rat corticospinal axons also regenerate into human donor grafts of caudal spinal cord identity. Collectively, these findings indicate that spinal cord 'replacement' with homologous neural stem cells enables robust regeneration of the corticospinal projection within and beyond spinal cord lesion sites, achieving a major unmet goal of SCI research and offering new possibilities for clinical translation.
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Affiliation(s)
- Ken Kadoya
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA.,Department of Orthopaedic Surgery, Hokkaido University, Sapporo, Japan
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA.,Veterans Administration San Diego Healthcare System, San Diego, California, USA
| | - Kenny Nguyen
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Corinne Lee-Kubli
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Lin Yao
- Waisman Center, University of Wisconsin-Madison, Wisconsin, USA.,Department of Neuroscience, University of Wisconsin-Madison, Wisconsin, USA.,Department of Neurology, University of Wisconsin-Madison, Wisconsin, USA
| | - Joshua Knackert
- Waisman Center, University of Wisconsin-Madison, Wisconsin, USA.,Department of Neuroscience, University of Wisconsin-Madison, Wisconsin, USA.,Department of Neurology, University of Wisconsin-Madison, Wisconsin, USA
| | - Gunnar Poplawski
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Hans Strobl
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Yoshio Takashima
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Jeremy Biane
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - James Conner
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Su-Chun Zhang
- Waisman Center, University of Wisconsin-Madison, Wisconsin, USA
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA.,Veterans Administration San Diego Healthcare System, San Diego, California, USA
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20
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van Niekerk EA, Tuszynski MH, Lu P, Dulin JN. Molecular and Cellular Mechanisms of Axonal Regeneration After Spinal Cord Injury. Mol Cell Proteomics 2015; 15:394-408. [PMID: 26695766 DOI: 10.1074/mcp.r115.053751] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 12/28/2022] Open
Abstract
Following axotomy, a complex temporal and spatial coordination of molecular events enables regeneration of the peripheral nerve. In contrast, multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration in the central nervous system. In this review, we examine the current understanding of differences in protein expression and post-translational modifications, activation of signaling networks, and environmental cues that may underlie the divergent regenerative capacity of central and peripheral axons. We also highlight key experimental strategies to enhance axonal regeneration via modulation of intraneuronal signaling networks and the extracellular milieu. Finally, we explore potential applications of proteomics to fill gaps in the current understanding of molecular mechanisms underlying regeneration, and to provide insight into the development of more effective approaches to promote axonal regeneration following injury to the nervous system.
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Affiliation(s)
- Erna A van Niekerk
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093;
| | - Mark H Tuszynski
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Paul Lu
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Jennifer N Dulin
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093
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21
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Affiliation(s)
- Jennifer N Dulin
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA ; Veterans Administration Medical Center, San Diego, CA, 92161, USA
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22
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Dulin JN, Moore ML, Grill RJ. The dual cyclooxygenase/5-lipoxygenase inhibitor licofelone attenuates p-glycoprotein-mediated drug resistance in the injured spinal cord. J Neurotrauma 2013; 30:211-26. [PMID: 22947335 DOI: 10.1089/neu.2012.2587] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There are currently no proven effective treatments that can improve recovery of function in spinal cord injury (SCI) patients. Many therapeutic compounds have shown promise in pre-clinical studies, but clinical trials have been largely unsuccessful. P-glycoprotein (Pgp, Abcb1b) is a drug efflux transporter of the blood-spinal cord barrier that limits spinal cord penetration of blood-borne xenobiotics. Pathological Pgp upregulation in diseases such as cancer causes heightened resistance to a broad variety of therapeutic drugs. Importantly, several drugs that have been evaluated for the treatment of SCI, such as riluzole, are known substrates of Pgp. We therefore examined whether Pgp-mediated pharmacoresistance diminishes delivery of riluzole to the injured spinal cord. Following moderate contusion injury at T10 in male Sprague-Dawley rats, we observed a progressive, spatial spread of increased Pgp expression from 3 days to 10 months post-SCI. Spinal cord uptake of i.p.-delivered riluzole was significantly reduced following SCI in wild type but not Abcb1a-knockout rats, highlighting a critical role for Pgp in mediating drug resistance following SCI. Because inflammation can drive Pgp upregulation, we evaluated the ability of the new generation dual anti-inflammatory drug licofelone to promote spinal cord delivery of riluzole following SCI. We found that licofelone both reduced Pgp expression and enhanced riluzole bioavailability within the lesion site at 72 h post-SCI. This work highlights Pgp-mediated drug resistance as an important obstacle to therapeutic drug delivery for SCI, and suggests licofelone as a novel combinatorial treatment strategy to enhance therapeutic drug delivery to the injured spinal cord.
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Affiliation(s)
- Jennifer N Dulin
- Department of Integrative Biology and Pharmacology, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
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