iPS cell technologies: significance and applications to CNS regeneration and disease

Abstract

In 2006, we demonstrated that mature somatic cells can be reprogrammed to a pluripotent state by gene transfer, generating induced pluripotent stem (iPS) cells. Since that time, there has been an enormous increase in interest regarding the application of iPS cell technologies to medical science, in particular for regenerative medicine and human disease modeling. In this review article, we outline the current status of applications of iPS technology to cell therapies (particularly for spinal cord injury), as well as neurological disease-specific iPS cell research (particularly for Parkinson's disease and Alzheimer's disease). Finally, future directions of iPS cell research are discussed including a) development of an accurate assay system for disease-associated phenotypes, b) demonstration of causative relationships between genotypes and phenotypes by genome editing, c) application to sporadic and common diseases, and d) application to preemptive medicine.

Figure 1

The history of investigations of cellular reprogramming that led to the development of iPS cells. Our generation of iPS cells in 2006 [4] became possible due to three scientific lines of investigation: 1) nuclear reprogramming, 2) factor-mediated cell fate conversion, and 3) ES cells. See the text for details (modified from Reference [5] with permission).

Figure 2

The application of iPS cell technologies to medical science. iPS cell technologies can be used for medical science including 1) cell therapies and 2) disease modeling or drug development. See the text for details.

Figure 3

Strategies for the development of iPS cell-based cell therapy for SCI patients. Our collaborative team (Okano’s group at Keio University and Yamanaka’s group at Kyoto University) have been developing an iPS cell-based cell therapy for SCI since 2006. Our previous preclinical studies have shown that long-term functional restoration can be obtained by transplantation of NS/PCs derived from appropriate iPS cells clones without observable tumor formation [10]. Currently, we aim to develop iPS cells-based cell therapy for SCI patients at sub-acute phase using the clinical grade iPS cell-derived NS/PCs (i.e., the role of Okano’s group described in the blue box) which have been prepared from human iPS cell stock (i.e., the role of Yamanaka’s group described in the yellow box).