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Goto T, Ubukawa K, Kobayashi I, Sugawara K, Asanuma K, Sasaki Y, Guo YM, Takahashi N, Sawada K, Wakui H, Nunomura W. ATP produced by anaerobic glycolysis is essential for enucleation of human erythroblasts. Exp Hematol 2019; 72:14-26.e1. [PMID: 30797950 DOI: 10.1016/j.exphem.2019.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/13/2019] [Accepted: 02/18/2019] [Indexed: 11/16/2022]
Abstract
More than 2million human erythroblasts extrude their nuclei every second in bone marrow under hypoxic conditions (<7% O2). Enucleation requires specific signal transduction pathways and the local assembly of contractile actomyosin rings. However, the energy source driving these events has not yet been identified. We examined whether different O2 environments (hypoxic [5% O2] and normoxic [21% O2] conditions) affected human CD34+ cell erythroblast differentiation. We also investigated the regulatory mechanisms underlying energy production in erythroblasts during terminal differentiation under 5% or 21% O2 conditions. The results obtained revealed that the enucleation ratio and intracellular levels of adenosine triphosphate (ATP), lactate dehydrogenase (LDH) M3H, and hypoxia-inducible factor 1α in erythroblasts during terminal differentiation were higher under the 5% O2 condition than under the 21% O2 condition. We also found that the enzymatic inhibition of glyceraldehyde 3-phosphate dehydrogenase and LDH, key enzymes in anaerobic glycolysis, blocked the proliferation of colony-forming units-erythroid and enucleation of erythroblasts, and also reduced ATP levels in erythroblasts under both hypoxic and normoxic conditions. Under both conditions, phosphorylation of the Ser232, Ser293, and Ser300 residues in pyruvate dehydrogenase (inactive state of the enzyme) in erythroblasts was involved in regulating the pathway governing energy metabolism during erythroid terminal differentiation. This reaction may be mediated by pyruvate dehydrogenase kinase (PDK) 4, the major PDK isozyme expressed in erythroblasts undergoing enucleation. Collectively, these results suggest that ATP produced by anaerobic glycolysis is the main source of energy for human erythroblast enucleation in the hypoxic bone marrow environment.
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Affiliation(s)
- Tatsufumi Goto
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan
| | - Kumi Ubukawa
- Department of Hematology, Nephrology, and Rheumatology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Isuzu Kobayashi
- Department of Hematology, Nephrology, and Rheumatology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Kotomi Sugawara
- Department of Hematology, Nephrology, and Rheumatology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Ken Asanuma
- Division of Radio Isotope, Bioscience Education and Research Support Center, Akita University, Akita, Japan
| | - Yumi Sasaki
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan
| | - Yong-Mei Guo
- Department of Hematology, Nephrology, and Rheumatology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Naoto Takahashi
- Department of Hematology, Nephrology, and Rheumatology, Graduate School of Medicine, Akita University, Akita, Japan
| | | | - Hideki Wakui
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan.
| | - Wataru Nunomura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan; Research Center for Engineering Science, Graduate School of Engineering Science, Akita University, Akita, Japan
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