Variations in Glycogen Synthesis in Human Pluripotent Stem Cells with Altered Pluripotent States

• Published in: PloS one Vol. 10; no. 11; p. e0142554
• Main Authors: Chen, Richard J, Zhang, Guofeng, Garfield, Susan H, Shi, Yi-Jun, Chen, Kevin G, Robey, Pamela G, Leapman, Richard D
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 13.11.2015; Public Library of Science (PLoS)
• Subjects: Bioengineering; Biophysics; Bone morphogenetic protein 4; Bone Morphogenetic Protein 4 - metabolism; Bone morphogenetic proteins; Cancer; Cell culture; Cell Differentiation; Cell Line; Cell Proliferation; Embryo cells; Embryonic stem cells; G proteins; Gene expression; Glucose metabolism; Glycogen; Glycogen - metabolism; Glycogen Synthase - metabolism; Glycogen synthase kinase 3; Glycogen Synthase Kinase 3 - metabolism; Glycogen synthesis; Growth conditions; Humans; Hypoxia; Immunofluorescence; Immunoglobulins; Induced Pluripotent Stem Cells - cytology; Induced Pluripotent Stem Cells - metabolism; Inhibitors; Kinases; Laboratories; Leukemia; Membrane proteins; Metabolic pathways; Metabolism; Microscopy; Neurological disorders; Oct-4 protein; Pluripotency; Pluripotent Stem Cells - cytology; Pluripotent Stem Cells - metabolism; Proteins; Regenerative medicine; Stem cells; Synthesis; Tumor cell lines; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0142554

Human pluripotent stem cells (hPSCs) represent very promising resources for cell-based regenerative medicine. It is essential to determine the biological implications of some fundamental physiological processes (such as glycogen metabolism) in these stem cells. In this report, we employ electron, immunofluorescence microscopy, and biochemical methods to study glycogen synthesis in hPSCs. Our results indicate that there is a high level of glycogen synthesis (0.28 to 0.62 μg/μg proteins) in undifferentiated human embryonic stem cells (hESCs) compared with the glycogen levels (0 to 0.25 μg/μg proteins) reported in human cancer cell lines. Moreover, we found that glycogen synthesis was regulated by bone morphogenetic protein 4 (BMP-4) and the glycogen synthase kinase 3 (GSK-3) pathway. Our observation of glycogen bodies and sustained expression of the pluripotent factor Oct-4 mediated by the potent GSK-3 inhibitor CHIR-99021 reveals an altered pluripotent state in hPSC culture. We further confirmed glycogen variations under different naïve pluripotent cell growth conditions based on the addition of the GSK-3 inhibitor BIO. Our data suggest that primed hPSCs treated with naïve growth conditions acquire altered pluripotent states, similar to those naïve-like hPSCs, with increased glycogen synthesis. Furthermore, we found that suppression of phosphorylated glycogen synthase was an underlying mechanism responsible for altered glycogen synthesis. Thus, our novel findings regarding the dynamic changes in glycogen metabolism provide new markers to assess the energetic and various pluripotent states in hPSCs. The components of glycogen metabolic pathways offer new assays to delineate previously unrecognized properties of hPSCs under different growth conditions.