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 2

Neuronal maturation over time.

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Neuronal maturation over time. (A) One month after grafting, human H9-NS...
(A) One month after grafting, human H9-NSCs expressed the human nuclear marker hNu; many cells also expressed the immature neuronal marker DCX in the cytoplasm. Inset shows image at higher magnification and colocalization of hNu and DCX. (B) Expression of DCX was substantially reduced by 3 months after grafting, and (C) at this time point, cells first express NeuN. Inset images show higher magnification. (D–I) Expression of the pan-neuronal marker Hu from 1 to 18 months after grafting. Insets show higher magnification. Many NSCs, labeled for GFP, also expressed Hu at 1 month. At 3 and 6 months, Hu+ cell numbers were substantially reduced and partially recovered by 12 and 18 months (quantified in M). (J–L) Hu cell distribution in the graft at 1, 6, and 18 months. Hu cell size increased over time (quantified in N) and adopted a more mature neuronal morphology. (O) Quantification of Hu fluorescence labeling intensity over time. All data represent the mean ± SEM. P < 0.001, ANOVA (M–O) and ***P < 0.001, **P < 0.01, and *P < 0.05, by Fisher’s exact post-hoc comparison test for 1 (n = 3), 3 (n = 3), 6 (n = 5), 12 (n = 3), and 18 months (n = 4). Scale bars: 32 μm (A–I); 250 μm (J–L). Original magnification of Images in insets: A, B, D, and E: ×1200; C, F–I: ×400.