Modulation by DREADD reveals the therapeutic effect of human iPSC-derived neuronal activity on functional recovery after spinal cord injury.

Takahiro Kitagawa,Masaya Nakamura,Morio Matsumoto,Narihito Nagoshi,Yasuhiro Kamata,Kentaro Ago,Munehisa Shinozaki,Tomoko Shindo,Shinsuke Shibata,Jun Kohyama,Kent Imaizumi,Momotaro Kawai,Hideyuki Okano,Yuta Sato,Keita Kajikawa,Reo Shibata

doi:10.1016/j.stemcr.2021.12.005

Abstract

SummaryTransplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) is considered to be a promising therapy for spinal cord injury (SCI) and will soon be translated to the clinical phase. However, how grafted neuronal activity influences functional recovery has not been fully elucidated. Here, we show the locomotor functional changes caused by inhibiting the neuronal activity of grafted cells using a designer receptor exclusively activated by designer drugs (DREADD). In vitro analyses of inhibitory DREADD (hM4Di)-expressing cells demonstrated the precise inhibition of neuronal activity via administration of clozapine N-oxide. This inhibition led to a significant decrease in locomotor function in SCI mice with cell transplantation, which was exclusively observed following the maturation of grafted neurons. Furthermore, trans-synaptic tracing revealed the integration of graft neurons into the host motor circuitry. These results highlight the significance of engrafting functionally competent neurons by hiPSC-NS/PC transplantation for sufficient recovery from SCI.

Highlights

Stem cell-based approaches have been reported to be an effective therapy for spinal cord injury (SCI) (Cummings et al, 2005; Kobayashi et al, 2012; Nori et al, 2011)
The present study aimed to evaluate the association of graft neuronal activity and host locomotor function in human induced pluripotent stem cells (hiPSCs)-derived neural stem/progenitor cells (NS/PCs) transplantation by controlling the neuronal activity using the inhibitory designer receptor exclusively activated by designer drugs (DREADD) receptor hM4Di (Nichols and Roth, 2009)
The activity of hM4Di-expressing neurons derived from hiPSC-NS/PCs was inhibited by administration of clozapine N-oxide (CNO) We used lentiviral vectors to label NS/PCs, which derived neurons expressing hM4Di fused with mCherry and neurons expressing only mCherry as a negative control (Figures 1A and 1B)

Summary

Introduction

Stem cell-based approaches have been reported to be an effective therapy for spinal cord injury (SCI) (Cummings et al, 2005; Kobayashi et al, 2012; Nori et al, 2011). Several beneficial factors of NS/PC transplantation have been proposed, including axonal regeneration with synaptic formation, remyelination, and neuroprotection by trophic factors (Assinck et al, 2017; Nori et al, 2017). Among these mechanisms, axonal regeneration is of great significance due to the characteristics of NS/PCs, which provide neuronal cells that integrate into host tissue and reconnect neuronal networks (Abematsu et al, 2010; Bonner et al, 2011; Bonner and Steward, 2015; Lu et al, 2012). Definitive evidence of the therapeutic mechanism mediated by integrated graft-derived neurons is crucial to promote hiPSC-NS/PC transplantation therapy for SCI, which is on the road toward clinical trials (Nagoshi et al, 2020; Tsuji et al, 2019)

Results

Discussion

Conclusion