Standardization of human-induced pluripotent stem cells by optimizing culture conditions and monitoring key parameters

The differentiation potential of human-induced pluripotent stem cells (hiPSCs) is not constant among clones, therefore standardization of iPSCs as a starting material is a key issue for the dissemination of hiPSC-based cell therapy. We showed that hiPSCs cultured with medium that supported the glycolytic pathway demonstrated a high level of chromodomain-helicase-DNA-binding protein 7 (CHD7) expression and retained differentiation potential. Notably, hiPSCs cultured with medium that supported mitochondrial activity expressed a low level of CHD7 and lost differentiation potential. In addition, we showed secretion of kynurenine by undifferentiated hiPSCs, and 2-AAA when differentiated. Thus, we propose re-cloning iPSC clones with medium supporting the glycolytic pathway for standardization, and measuring the expression of CHD7 by flow cytometry to check the differentiation potential and measuring Kynurenine and 2-AAA levels in the culture medium to monitor and assure the differentiation status of cells during culture.