Identifying the most effective types of integration-free human iPS cell-derived neural stem/progenitor cells in the treatment of spinal cord injury
Authors: T. IIDA, N. NAGOSHI, J. KOHYAMA, O. TSUJI, M. MATSUMOTO, M. NAKAMURA, H. OKANO
INTRODUCTION: We have previously demonstrated the therapeutic potential of transplanting human iPS cell-derived neural stem/progenitor cells (hiPSC-NS/PCs) in the treatment of spinal cord injury (SCI) models. Recently, we have produced integration-free hiPSCs using episomal vectors which is safer for clinical use. The purpose of this study is to assess the efficacy of integration-free hiPSC-NS/PCs, and to investigate their genetic profiles in order to evaluate factors related to therapeutic efficacy. METHODS: Two integration-free human iPS cell lines were prepared (836B3-, 414C2-hiPSCs), and were induced to hiPSC-NS/PCs (836B3-, 414C2-NS/PCs). ES cells were also used for analysis as a target for comparison of hiPSCs. hiPSC-NS/PCs were transplanted into the injured spinal cord of NOD-SCID mice, and phosphate buffered saline (PBS) was injected to the control group (414C2-NS/PCs; n=27, 836B3-NS/PCs; n=23, control; n=15). Transplanted cells were monitored using bio-imaging and evaluated histologically; and motor function was evaluated by basso mouse scale (BMS) score. HumanHT-12 was used to evaluate gene-expression analyses and single-cell-RNA-sequence was performed using Illumina-Hiseq2500. RESULTS: In the in-vivo study, better motor functional recovery was observed in the 414C2-NS/PCs group compared with the control group (p< 0.001). In contrast, 836B3-NS/PCs group showed no improvement in motor function, and formed undifferentiated tissues. The gene-expression profile of 414C2-hiPSCs resembled that of ES cells with clustering analysis, and 12 genes which included genome-stabilization gene such as DPPA3 and differentiation related genes such as IRX2 were highly expressed in 414C2-hiPSCs, similar to those found in ES cells. None of these findings, however, were observed in 836B3-hiPSCs. In single-cell-RNA-sequence, Delta-Notch signal positive cells which are important for neural differentiation were more abundant in 414C2-NS/PCs, whereas 836B3-NS/PCs only contained a small population (12% and 5%, respectively).
DISCUSSION: In order to pursue our mission of conducting a clinical trial for SCI patients within the next several years, it is critical to build guidelines for selecting “effective” hiPSC-NS/PCs, such as 414C2-NS/PCs. Herein we showed that the key to good motor function recovery is to transplant integration-free hiPSC-NS/PCs that differentiate well within the spinal cord tissue. Our results suggest that examining hiPSCs quality with 12-gene markers and establishing hiPSC-NS/PCs that contain Delta-Notch (+) cells for more than 10% could be the criteria to select “effective” hiPSC-NS/PCs for SCI treatment.
*T. IIDA1, N. NAGOSHI1, J. KOHYAMA2, O. TSUJI1, M. MATSUMOTO1, M. NAKAMURA1, H. OKANO2;
1Dept of Orthop, Sch. of Med, Keio Univ., Shinjyuku-Ku Tokyo, Japan; 2Dept of Physiology, Sch. of Med, Keio Univ., Shinjyuku-Ku Tokyo, Japan. Identifying the most effective types of integration-free human iPS cell-derived neural stem/progenitor cells in the treatment of spinal cord injury. Program No. 213.06. 2018 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2018. Online.
Keio researchers plan to treat spinal cord injuries with stem cells at The Japan Times News LINK