Human induced pluripotent stem cells (hiPSCs): Generation, characterization, and differentiation

Human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs), which are called as human pluripotent stem cells (hPSCs), are valuable cell sources in cell therapies such as clinical treatment for many diseases. This is because hPSCs hold the specific ability to induce differentiation into all types of tissue cells in our human bodies (Higuchi et al., 2011, 2017, 2019). hESCs and hiPSCs that were induced to differentiation into beta cells secreting insulin and neurons secreting dopamine are promising to be used for the transplantation of these cells for the cure of diabetes and Parkinson’s disease, respectively. The potential stem cell-based therapies and possible drug discovery platforms will be developed from pluripotent characteristics of hPSCs in future. Although hESCs are promising donor sources for cell transplantation therapies, they face immune rejection after their transplantation, and furthermore, hESC usage in the clinics holds ethical issues originated from the usage of human embryos. These drawbacks could be solved by using hiPSCs obtained directly from patients’ tissue cells or shelve-off hiPSCs (Takahashi et al., 2007; Vodyanik et al., 2008). hiPSCs can be generated from tissue cells by the “forced” expression of pluripotency genes or proteins, such as Klf-4, Oct3/4, Sox2, and c-Myc (or L-Myc) or Oct3/4, Sox2, Nanog, and Ln28 (Takahashi et al., 2007; Vodyanik et al., 2008). hiPSCs’ characteristics are considered to be similar to hESCs in many aspects, such as differentiation ability into many types of tissue cells, teratoma formation potential, embryoid body formation potential, chromatin methylation patterns, doubling time, and the expression of stem cell proteins or genes. In this chapter, we discuss recent development of hiPSC generation, characterization, and differentiation into some specific lineage of the cells.