, Volume 16, Issue 6, pp 865-876
Date: 21 May 2014

Noninvasive Reporter Gene Imaging of Human Oct4 (Pluripotency) Dynamics During the Differentiation of Embryonic Stem Cells in Living Subjects

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Abstract

Purpose

Human pluripotency gene networks (PGNs), controlled in part by Oct4, are central to understanding pluripotent stem cells, but current fluorescent reporter genes (RGs) preclude noninvasive assessment of Oct4 dynamics in living subjects.

Procedures

To assess Oc4 activity noninvasively, we engineered a mouse embryonic stem cell line which encoded both a pOct4-hrluc (humanized renilla luciferase) reporter and a pUbi-hfluc2-gfp (humanized firefly luciferase 2 fused to green fluorescent protein) reporter.

Results

In cell culture, pOct4-hRLUC activity demonstrated a peak at 48 h (day 2) and significant downregulation by 72 h (day 3) (p=0.0001). Studies in living subjects demonstrated significant downregulation in pOct4-hRLUC activity between 12 and 144 h (p = 0.001) and between 12 and 168 h (p = 0.0003). pOct4-hRLUC signal dynamics after implantation was complex, characterized by transient upregulation after initial downregulation in all experiments (n = 10, p = 0.01). As expected, cell culture differentiation of the engineered mouse embryonic stem cell line demonstrated activation of mesendodermal, mesodermal, endodermal, and ectodermal master regulators of differentiation, indicating potency to form all three germ layers.

Conclusions

We conclude that the Oct4-hrluc RG system enables noninvasive Oct4 imaging in cell culture and in living subjects.

Byeong-Cheol Ahn and Natesh Parashurama contributed equally to this work.