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Li K, Peng L, Xing Q, Zuo X, Huang W, Zhan L, Li H, Sun W, Zhong X, Zhu T, Pan G, Xu E. Transplantation of hESCs-Derived Neural Progenitor Cells Alleviates Secondary Damage of Thalamus After Focal Cerebral Infarction in Rats. Stem Cells Transl Med 2023; 12:553-568. [PMID: 37399126 PMCID: PMC10428088 DOI: 10.1093/stcltm/szad037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 06/04/2023] [Indexed: 07/05/2023] Open
Abstract
Human embryonic stem cells-derived neural progenitor cells (hESCs-NPCs) transplantation holds great potential to treat stroke. We previously reported that delayed secondary degeneration occurs in the ventroposterior nucleus (VPN) of ipsilateral thalamus after distal branch of middle cerebral artery occlusion (dMCAO) in adult male Sprague-Dawley (SD) rats. In this study, we investigate whether hESCs-NPCs would benefit the neural recovery of the secondary damage in the VPN after focal cerebral infarction. Permanent dMCAO was performed with electrocoagulation. Rats were randomized into Sham, dMCAO groups with or without hESCs-NPCs treatment. HESCs-NPCs were engrafted into the peri-infarct regions of rats at 48 h after dMCAO. The transplanted hESCs-NPCs survive and partially differentiate into mature neurons after dMCAO. Notably, hESCs-NPCs transplantation attenuated secondary damage of ipsilateral VPN and improved neurological functions of rats after dMCAO. Moreover, hESCs-NPCs transplantation significantly enhanced the expression of BDNF and TrkB and their interaction in ipsilateral VPN after dMCAO, which was reversed by the knockdown of TrkB. Transplantated hESCs-NPCs reconstituted thalamocortical connection and promoted the formation of synapses in ipsilateral VPN post-dMCAO. These results suggest that hESCs-NPCs transplantation attenuates secondary damage of ipsilateral thalamus after cortical infarction, possibly through activating BDNF/TrkB pathway, enhancing thalamocortical projection, and promoting synaptic formation. It provides a promising therapeutic strategy for secondary degeneration in the ipsilateral thalamus post-dMCAO.
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Affiliation(s)
- Kongping Li
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Linhui Peng
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Qi Xing
- Department of Neurology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangdong, People’s Republic of China
| | - Xialin Zuo
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Wenhao Huang
- Department of Neurology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangdong, People’s Republic of China
| | - Lixuan Zhan
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Heying Li
- Department of Neurology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangdong, People’s Republic of China
| | - Weiwen Sun
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Xiaofen Zhong
- Department of Neurology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangdong, People’s Republic of China
| | - Tieshi Zhu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Guangjin Pan
- Department of Neurology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Science Park, Guangdong, People’s Republic of China
| | - En Xu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China
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Thomas J, Martinez-Reza MF, Thorwirth M, Zarb Y, Conzelmann KK, Hauck SM, Grade S, Götz M. Excessive local host-graft connectivity in aging and amyloid-loaded brain. SCIENCE ADVANCES 2022; 8:eabg9287. [PMID: 35687689 PMCID: PMC9187230 DOI: 10.1126/sciadv.abg9287] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/25/2022] [Indexed: 05/24/2023]
Abstract
Transplantation is a clinically relevant approach for brain repair, but much remains to be understood about influences of the disease environment on transplant connectivity. To explore the effect of amyloid pathology in Alzheimer's disease (AD) and aging, we examined graft connectivity using monosynaptic rabies virus tracing in APP/PS1 mice and in 16- to 18-month-old wild-type (WT) mice. Transplanted neurons differentiated within 4 weeks and integrated well into the host visual cortex, receiving input from the appropriate brain regions for this area. Unexpectedly, we found a prominent several-fold increase in local inputs, in both amyloid-loaded and aged environments. State-of-the-art deep proteome analysis using mass spectrometry highlights complement system activation as a common denominator of environments promoting excessive local input connectivity. These data therefore reveal the key role of the host pathology in shaping the input connectome, calling for caution in extrapolating results from one pathological condition to another.
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Affiliation(s)
- Judith Thomas
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
| | - Maria Fernanda Martinez-Reza
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
| | - Manja Thorwirth
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
| | - Yvette Zarb
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer-Institute of Virology, Medical Faculty and Gene Center, Ludwig-Maximilians Universitaet Muenchen, D-81377 Muenchen, Germany
| | - Stefanie M. Hauck
- Research Unit Protein Science and Metabolomics and Proteomics Core, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
| | - Sofia Grade
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, D-85764 Neuherberg, Germany
- SYNERGY, Excellence Cluster for Systems Neurology, Ludwig-Maximilians Universitaet Muenchen, D-82152 Planegg, Germany
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Grade S, Thomas J, Zarb Y, Thorwirth M, Conzelmann KK, Hauck SM, Götz M. Brain injury environment critically influences the connectivity of transplanted neurons. SCIENCE ADVANCES 2022; 8:eabg9445. [PMID: 35687687 PMCID: PMC9187233 DOI: 10.1126/sciadv.abg9445] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cell transplantation is a promising approach for the reconstruction of neuronal circuits after brain damage. Transplanted neurons integrate with remarkable specificity into circuitries of the mouse cerebral cortex affected by neuronal ablation. However, it remains unclear how neurons perform in a local environment undergoing reactive gliosis, inflammation, macrophage infiltration, and scar formation, as in traumatic brain injury (TBI). To elucidate this, we transplanted cells from the embryonic mouse cerebral cortex into TBI-injured, inflamed-only, or intact cortex of adult mice. Brain-wide quantitative monosynaptic rabies virus (RABV) tracing unraveled graft inputs from correct regions across the brain in all conditions, with pronounced quantitative differences: scarce in intact and inflamed brain versus exuberant after TBI. In the latter, the initial overshoot is followed by pruning, with only a few input neurons persisting at 3 months. Proteomic profiling identifies candidate molecules for regulation of the synaptic yield, a pivotal parameter to tailor for functional restoration of neuronal circuits.
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Affiliation(s)
- Sofia Grade
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Center for Environmental Health, 82152 Planegg-Martinsried, Germany
- Corresponding author. (S.G.); (S.M.H.); (M.G.)
| | - Judith Thomas
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Center for Environmental Health, 82152 Planegg-Martinsried, Germany
- Graduate School of Systemic Neuroscience, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Yvette Zarb
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Center for Environmental Health, 82152 Planegg-Martinsried, Germany
| | - Manja Thorwirth
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Center for Environmental Health, 82152 Planegg-Martinsried, Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer Institute Virology, Medical Faculty and Gene Center, Ludwig-Maximilians University Munich, 81377 Munich, Germany
| | - Stefanie M. Hauck
- Research Unit Protein Science and Metabolomics and Proteomics Core, Helmholtz Center Munich, German Center for Environmental Health, 85764 Neuherberg, Germany
- Corresponding author. (S.G.); (S.M.H.); (M.G.)
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Center for Environmental Health, 82152 Planegg-Martinsried, Germany
- SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Corresponding author. (S.G.); (S.M.H.); (M.G.)
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Physical exercise promotes integration of grafted cells and functional recovery in an acute stroke rat model. Stem Cell Reports 2022; 17:276-288. [PMID: 35030322 PMCID: PMC8828662 DOI: 10.1016/j.stemcr.2021.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 11/23/2022] Open
Abstract
Human neural progenitor cell (hNPC) transplantation holds great potential to treat neurological diseases. However, hNPC grafts take a long time to differentiate into mature neurons due to their intrinsically prolonged developmental timetable. Here, we report that postoperative physical exercise (PE), a prevailing rehabilitation intervention, promotes the neuronal commitment, maturation, and integration of engrafted hNPCs, evidenced by forming more synapses, receiving more synaptic input from host neurons, and showing higher neuronal activity levels. More important, NPC transplantation, combined with PE, shows significant improvement in both structural and behavioral outcomes in stroke-damaged rats. PE enhances ingrowth of blood vessels around the infarction region and neural tract reorganization along the ischemic boundary. The combination of NPC transplantation and postoperative PE creates both a neurotrophic/growth factor-enriched proneuronal microenvironment and an ideal condition for activity-dependent plasticity to give full play to its effects. Our study provides a potential approach to treating patients with stroke injury. Physical exercise boosts the maturation and integration of engrafted human NPCs This strategy brings about both structural and behavioral improvements in stroke rats This strategy creates a neurotrophic factor-enriched microenvironment Activity-dependent plasticity is also involved in this process
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Liu C, Wang X, Huang W, Meng W, Su Z, Xing Q, Shi H, Zhang D, Zhou M, Zhao Y, Wang H, Pan G, Zhong X, Pei D, Guo Y. Hypoproliferative human neural progenitor cell xenografts survived extendedly in the brain of immunocompetent rats. Stem Cell Res Ther 2021; 12:376. [PMID: 34215315 PMCID: PMC8254296 DOI: 10.1186/s13287-021-02427-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
Background There is a huge controversy about whether xenograft or allograft in the “immune-privileged” brain needs immunosuppression. In animal studies, the prevailing sophisticated use of immunosuppression or immunodeficient animal is detrimental for the recipients, which results in a short lifespan of animals, confounds functional behavioral readout of the graft benefits, and discourages long-term follow-up. Methods Neuron-restricted neural progenitor cells (NPCs) were derived from human embryonic stem cells (ESCs, including H1, its gene-modified cell lines for better visualization, and HN4), propagated for different passages, and then transplanted into the brain of immunocompetent rats without immunosuppressants. The graft survivals, their cell fates, and HLA expression levels were examined over time (up to 4 months after transplantation). We compared the survival capability of NPCs from different passages and in different transplantation sites (intra-parenchyma vs. para- and intra-cerebroventricle). The host responses to the grafts were also investigated. Results Our results show that human ESC-derived neuron-restricted NPCs survive extendedly in adult rat brain parenchyma with no need of immunosuppression whereas a late-onset graft rejection seems inevitable. Both donor HLA antigens and host MHC-II expression level remain relatively low with little change over time and cannot predict the late-onset rejection. The intra-/para-cerebroventricular human grafts are more vulnerable to the immune attack than the intrastriatal counterparts. Prevention of graft hyperplasia by using hypoproliferative late passaged human NPCs further significantly extends the graft survival time. Our new data also shows that a subpopulation of host microglia upregulate MHC-II expression in response to the human graft, but fail to present the human antigen to the host immune system, suggestive of the immune-isolation role of the blood–brain barrier (BBB). Conclusions The present study confirms the “immune privilege” of the brain parenchyma and, more importantly, unveils that choosing hypoproliferative NPCs for transplantation can benefit graft outcome in terms of both lower tumor-genic risk and the prolonged survival time without immunosuppression. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-021-02427-1.
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Affiliation(s)
- Chunhua Liu
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), Guangzhou, 510005, China
| | - Xiaoyun Wang
- Guangdong Work Injury Rehabilitation Center, Guangzhou, 510440, China
| | - Wenhao Huang
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Wei Meng
- Guangdong Work Injury Rehabilitation Center, Guangzhou, 510440, China
| | - Zhenghui Su
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Qi Xing
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Heng Shi
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Di Zhang
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Min Zhou
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Yifan Zhao
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), Guangzhou, 510005, China
| | - Haitao Wang
- CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Guangjin Pan
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China
| | - Xiaofen Zhong
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.
| | - Duanqing Pei
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China. .,Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), Guangzhou, 510005, China.
| | - Yiping Guo
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China. .,Drug Discovery Pipeline, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong Province, China.
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Affiliation(s)
| | - Ying Lou
- The Chinese Society for Cell Biology, Shanghai, China.
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7
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Adler AF, Björklund A, Parmar M. Transsynaptic tracing and its emerging use to assess graft-reconstructed neural circuits. Stem Cells 2020; 38:716-726. [PMID: 32101353 DOI: 10.1002/stem.3166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/20/2020] [Accepted: 02/19/2020] [Indexed: 12/16/2022]
Abstract
Fetal neural progenitor grafts have been evaluated in preclinical animal models of spinal cord injury and Parkinson's disease for decades, but the initial reliance on primary tissue as a cell source limited the scale of their clinical translatability. With the development of robust methods to differentiate human pluripotent stem cells to specific neural subtypes, cell replacement therapy holds renewed promise to treat a variety of neurodegenerative diseases and injuries at scale. As these cell sources are evaluated in preclinical models, new transsynaptic tracing methods are making it possible to study the connectivity between host and graft neurons with greater speed and detail than was previously possible. To date, these studies have revealed that widespread, long-lasting, and anatomically appropriate synaptic contacts are established between host and graft neurons, as well as new aspects of host-graft connectivity which may be relevant to clinical cell replacement therapy. It is not yet clear, however, whether the synaptic connectivity between graft and host neurons is as cell-type specific as it is in the endogenous nervous system, or whether that connectivity is responsible for the functional efficacy of cell replacement therapy. Here, we review evidence suggesting that the new contacts established between host and graft neurons may indeed be cell-type specific, and how transsynaptic tracing can be used in the future to further elucidate the mechanisms of graft-mediated functional recovery in spinal cord injury and Parkinson's disease.
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Affiliation(s)
- Andrew F Adler
- Developmental and Regenerative Neurobiology, Department of Experimental Medical Science, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Anders Björklund
- Developmental and Regenerative Neurobiology, Department of Experimental Medical Science, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Malin Parmar
- Developmental and Regenerative Neurobiology, Department of Experimental Medical Science, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.,Lund Stem Cell Center, Lund University, Lund, Sweden
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