Glycerol-3-phosphate acyltransferase-1 upregulation by O-GlcNAcylationof Sp1 protects against hypoxia-induced mouse embryonic stem cellapoptosis via mTOR activation
| Autor: | Jung Min Ryu, Hyo-Pyo Lee, Dah Ihm Kim, Kwang Hyuck Lee, Yushin Jung, Ho Jae Han |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Cancer Research Programmed cell death Glycosylation Sp1 Transcription Factor Immunology Apoptosis P70-S6 Kinase 1 Biology Skin Diseases Mice 03 medical and health sciences Cellular and Molecular Neuroscience Animals Enzyme Inhibitors Phosphorylation RNA Small Interfering PI3K/AKT/mTOR pathway Cell Nucleus Sirolimus Glucosamine Cell growth TOR Serine-Threonine Kinases RPTOR Mouse Embryonic Stem Cells Cell Biology Embryonic stem cell Cell Hypoxia Up-Regulation Cell biology Disease Models Animal 030104 developmental biology Glycerol-3-Phosphate O-Acyltransferase RNA Interference Original Article Stem cell |
| Zdroj: | CELL DEATH & DISEASE(7) Cell Death & Disease |
| Popis: | Oxygen signaling is critical for stem cell regulation, and oxidative stress-induced stem cell apoptosis decreases the efficiency of stem cell therapy. Hypoxia activates O-linked β-N-acetyl glucosaminylation (O-GlcNAcylation) of stem cells, which contributes to regulation of cellular metabolism, as well as cell fate. Our study investigated the role of O-GlcNAcylation via glucosamine in the protection of hypoxia-induced apoptosis of mouse embryonic stem cells (mESCs). Hypoxia increased mESCs apoptosis in a time-dependent manner. Moreover, hypoxia also slightly increased the O-GlcNAc level. Glucosamine treatment further enhanced the O-GlcNAc level and prevented hypoxia-induced mESC apoptosis, which was suppressed by O-GlcNAc transferase inhibitors. In addition, hypoxia regulated several lipid metabolic enzymes, whereas glucosamine increased expression of glycerol-3-phosphate acyltransferase-1 (GPAT1), a lipid metabolic enzyme producing lysophosphatidic acid (LPA). In addition, glucosamine-increased O-GlcNAcylation of Sp1, which subsequently leads to Sp1 nuclear translocation and GPAT1 expression. Silencing of GPAT1 by gpat1 siRNA transfection reduced glucosamine-mediated anti-apoptosis in mESCs and reduced mammalian target of rapamycin (mTOR) phosphorylation. Indeed, LPA prevented mESCs from undergoing hypoxia-induced apoptosis and increased phosphorylation of mTOR and its substrates (S6K1 and 4EBP1). Moreover, mTOR inactivation by rapamycin (mTOR inhibitor) increased pro-apoptotic proteins expressions and mESC apoptosis. Furthermore, transplantation of non-targeting siRNA and glucosamine-treated mESCs increased cell survival and inhibited flap necrosis in mouse skin flap model. Conversely, silencing of GPAT1 expression reversed those glucosamine effects. In conclusion, enhancing O-GlcNAcylation of Sp1 by glucosamine stimulates GPAT1 expression, which leads to inhibition of hypoxia-induced mESC apoptosis via mTOR activation. |
| Databáze: | OpenAIRE |
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