Prolonged human neural stem cell maturation supports recovery in injured rodent CNS
Paul Lu, … , Eileen Staufenberg, Mark H. Tuszynski
Paul Lu, … , Eileen Staufenberg, Mark H. Tuszynski
Published August 21, 2017
Citation Information: J Clin Invest. 2017;127(9):3287-3299. https://doi.org/10.1172/JCI92955.
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Research Article Neuroscience

Prolonged human neural stem cell maturation supports recovery in injured rodent CNS

Abstract

Neural stem cells (NSCs) differentiate into both neurons and glia, and strategies using human NSCs have the potential to restore function following spinal cord injury (SCI). However, the time period of maturation for human NSCs in adult injured CNS is not well defined, posing fundamental questions about the design and implementation of NSC-based therapies. This work assessed human H9 NSCs that were implanted into sites of SCI in immunodeficient rats over a period of 1.5 years. Notably, grafts showed evidence of continued maturation over the entire assessment period. Markers of neuronal maturity were first expressed 3 months after grafting. However, neurogenesis, neuronal pruning, and neuronal enlargement continued over the next year, while total graft size remained stable over time. Axons emerged early from grafts in very high numbers, and half of these projections persisted by 1.5 years. Mature astrocyte markers first appeared after 6 months, while more mature oligodendrocyte markers were not present until 1 year after grafting. Astrocytes slowly migrated from grafts. Notably, functional recovery began more than 1 year after grafting. Thus, human NSCs retain an intrinsic human rate of maturation, despite implantation into the injured rodent spinal cord, yet they support delayed functional recovery, a finding of great importance in planning human clinical trials.

Authors

Paul Lu, Steven Ceto, Yaozhi Wang, Lori Graham, Di Wu, Hiromi Kumamaru, Eileen Staufenberg, Mark H. Tuszynski

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Figure 7

Human glial migration from graft site into host white matter.

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Human glial migration from graft site into host white matter. (A and B) ...
(A and B) Human NSCs migrated out of the graft into host white matter, beginning 3 months after grafting, as indicated by colocalization of GFP with the human-specific nuclear marker hNu. (A) Horizontal section 3 mm caudal to the graft (inset is a Z-stack image); (B) coronal section at C8 (inset is a higher-magnification image from the dorsal column region, indicated by an asterisk). (C and D) More extensive human NSC migration was evident 6 months after grafting at the same level as in A, 3 mm caudal to the graft. (E and F) Human cell migration at C8 and T6 after 12 months; insets show regions of sampling, colabeled for NeuN. (G–I) Human cell migration at C8, T6, and T12 at 18 months. (J and K) Migrated human cells (GFP+) colocalized with pan-GFAP (pGFAP); C8 coronal section 18 months after grafting. (L) Confocal Z-stack image showing colocalization of GFP and pGFAP at C8. (M and N) Z-stack images showing colocalization of GFP+ and hNu+ human cells with the human-specific astroglial marker hGFAP, 18 months after grafting. (M) Horizontal section 3 mm caudal to the graft; (N) coronal section at C8. (O) Z-stack image showing GFP and hNu coexpressing the cell proliferation marker Ki67, 12 months after grafting in a C7 horizontal section. Scale bars: 28 μm (A and C); 100 μm (B); 18 μm (D–I); 260 μm (J and K); 3 μm (L); 7 μm (M); 5 μm (N and O). Original magnification of insets: ×1200 (A); ×400 (B); ×40 (D–I).