Human neural progenitors derived from integration-free iPSCs for SCI therapy

Abstract

As a potentially unlimited autologous cell source, patient induced pluripotent stem cells (iPSCs) provide great capability for tissue regeneration, particularly in spinal cord injury (SCI). However, despite significant progress made in translation of iPSC-derived neural progenitor cells (NPCs) to clinical settings, a few hurdles remain. Among them, non-invasive approach to obtain source cells in a timely manner, safer integration-free delivery of reprogramming factors, and purification of NPCs before transplantation are top priorities to overcome. In this study, we developed a safe and cost-effective pipeline to generate clinically relevant NPCs. We first isolated cells from patients’ urine and reprogrammed them into iPSCs by non-integrating Sendai viral vectors, and carried out experiments on neural differentiation. NPCs were purified by A2B5, an antibody specifically recognizing a glycoganglioside on the cell surface of neural lineage cells, via fluorescence activated cell sorting. Upon further in vitro induction, NPCs were able to give rise to neurons, oligodendrocytes and astrocytes. To test the functionality of the A2B5+ NPCs, we grafted them into the contused mouse thoracic spinal cord. Eight weeks after transplantation, the grafted cells survived, integrated into the injured spinal cord, and differentiated into neurons and glia. Our specific focus on cell source, reprogramming, differentiation and purification method purposely addresses timing and safety issues of transplantation to SCI models. It is our belief that this work takes one step closer on using human iPSC derivatives to SCI clinical settings.

Induced Pluripotent Stem Cell Transplantation Improves Locomotor Recovery in Rat Models of Spinal Cord Injury: a Systematic Review and Meta-Analysis of Randomized Controlled Trials

“…A possible explanation for this might be that iPSC are one of the most widely used cell types for transplantation performed to recover the functions impaired as a result of injury [32]. In addition, the mechanism by which iPSC transplantation mediated functional improvements after SCI is multifaceted [33][34][35] although it is commonly accepted that iPSC transplantation can [7]: 1) reduce the area of syringomyelia and increase the area of spared tissue; 2) promote local microvascular regeneration and nerve regeneration for the repair of damaged cells; 3) reduce inflammation and inhibit oxidative stress after SCI; and 4) improve axonal growth and reconstruction of neural pathways by secreting substrates. Moreover, our findings are consistent with the data obtained in the study reported by Führmann et al, which demonstrated that transplantation of pluripotent stem cells and their differentiated progeny has the potential to regenerate functional pathways and improve locomotor function after SCI [36].…”

Advances in Pluripotent Stem Cells: History, Mechanisms, Technologies, and Applications

“…Integration-free neural progenitor cells generated by reprogramming of epithelial-like cells from human urine can be differentiated into multiple functional neuronal and glial subtypes in vitro [48]. Recent data obtained in experimental animal models showed that reprogrammed integrationfree iPSCs derived from human neural progenitors collected from urine differentiated into neurons and glia within 8 weeks of being transplanted into contused mouse thoracic spinal cords, though the study lacked functional data with respect to SCI recovery and included the oncogene c-Myc in its reprogramming protocol [49].…”

Progress in the Use of Induced Pluripotent Stem Cell-Derived Neural Cells for Traumatic Spinal Cord Injuries in Animal Populations: Meta-Analysis and Review

“…Out of a total of 22 reports that assessed iPSC‐derived neural cells for SCI treatment, the following studies were incorporated into the meta‐analysis . A few studies were excluded, because statistical significance could not be verified, motor recovery was not assessed, used a different scale to assess motor recovery, or focused on a cervical SCI model. Other studies were conducted in primates using iPSCs, and insufficient data were provided to perform a separate t ‐statistic.…”