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DeMambro VE, Tian L, Karthik V, Rosen CJ, Guntur AR. Effects of PTH on osteoblast bioenergetics in response to glucose. Bone Rep 2023; 19:101705. [PMID: 37576927 PMCID: PMC10412867 DOI: 10.1016/j.bonr.2023.101705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/29/2023] [Accepted: 07/13/2023] [Indexed: 08/15/2023] Open
Abstract
Parathyroid hormone acts through its receptor, PTHR1, expressed on osteoblasts, to control bone remodeling. Metabolic flexibility for energy generation has been demonstrated in several cell types dependent on substrate availability. Recent studies have identified a critical role for PTH in regulating glucose, fatty acid and amino acid metabolism thus stimulating both glycolysis and oxidative phosphorylation. Therefore, we postulated that PTH stimulates increased energetic output by osteoblasts either by increasing glycolysis or oxidative phosphorylation depending on substrate availability. To test this hypothesis, undifferentiated and differentiated MC3T3E1C4 calvarial pre-osteoblasts were treated with PTH to study osteoblast bioenergetics in the presence of exogenous glucose. Significant increases in glycolysis with acute ∼1 h PTH treatment with minimal effects on oxidative phosphorylation in undifferentiated MC3T3E1C4 in the presence of exogenous glucose were observed. In differentiated cells, the increased glycolysis observed with acute PTH was completely blocked by pretreatment with a Glut1 inhibitor (BAY-876) resulting in a compensatory increase in oxidative phosphorylation. We then tested the effect of PTH on the function of complexes I and II of the mitochondrial electron transport chain in the absence of glycolysis. Utilizing a novel cell plasma membrane permeability mitochondrial (PMP) assay, in combination with complex I and II specific substrates, slight but significant increases in basal and maximal oxygen consumption rates with 24 h PTH treatment in undifferentiated MC3T3E1C4 cells were noted. Taken together, our data demonstrate for the first time that PTH stimulates both increases in glycolysis and the function of the electron transport chain, particularly complexes I and II, during high energy demands in osteoblasts.
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Affiliation(s)
- Victoria E. DeMambro
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, ME, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Li Tian
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, ME, USA
| | - Vivin Karthik
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Clifford J. Rosen
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, ME, USA
- Tufts University School of Medicine, Tufts University, Boston, MA, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anyonya R. Guntur
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, ME, USA
- Tufts University School of Medicine, Tufts University, Boston, MA, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
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Shin YN, Lim CS, Tian YS, Rho WY, Cho BR. Detection of Near-membrane Calcium Ions in Live Tissues with a Two-Photon Fluorescent Probe. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.03.599] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mohan PS, Lim CS, Tian YS, Roh WY, Lee JH, Cho BR. A two-photon fluorescent probe for near-membrane calcium ions in live cells and tissues. Chem Commun (Camb) 2009:5365-7. [PMID: 19724786 DOI: 10.1039/b911337a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A two-photon fluorescent probe (ACaL) is reported that can be excited by 780 nm fs pulses, shows high photostability and negligible toxicity, and can visualize near-membrane Ca2+ in live cells and deep inside live tissues by two-photon microscopy.
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