Plant-derived human recombinant growth factors and serum albumin maintain stemness of human-induced pluripotent stem cells.

Stem cells are an important therapeutic source for recovery and regeneration, as their ability of self-renewal and differentiation offers an unlimited supply of highly specialized cells for therapeutic transplantation. Growth factors and serum are essential for maintaining the characteristics of stem cells in culture and for inducing differentiation. Because growth factors are produced mainly in bacterial (Escherichia coli) or animal cells, the use of such growth factors raises safety concerns that need to be resolved for the commercialization of stem cell therapeutics. To overcome this problem, studies on proteins produced in plants have been conducted. Here, we describe the functions of plant-derived fibroblast growth factor 2 (FGF2) and human serum albumin in the maintenance and differentiation of human-induced pluripotent stem cells (hiPSCs). Plant-derived FGF2 and human epidermal growth factor EGF were able to differentiate hiPSCs into neural stem cells (NSCs). These NSCs could differentiate into neuronal and glial cells. Our results imply that culturing stem cells in animal-free culture medium, which is composed of plant-derived proteins, would facilitate stem cell application research, for example, for cell therapy, by reducing contamination risk.