TY - JOUR
T1 - Excess exogenous pyruvate inhibits lactate dehydrogenase activity in live cells in an MCT1-dependent manner
AU - Rao, Yi
AU - Gammon, Seth T.
AU - Sutton, Margie N.
AU - Zacharias, Niki M.
AU - Bhattacharya, Pratip
AU - Piwnica-Worms, David
N1 - Funding Information:
Acknowledgments—This study was funded by the National Institutes of Health grant P50 CA94056 to the MD Anderson Cancer Center-Washington University Inter-Institutional Molecular Imaging Center, the Gerald Dewey Dodd, Jr, Endowed Distinguished Chair of the University of Texas MD Anderson Cancer Center, a faculty UT STARs Award, a University of Texas MD Anderson Cancer Center Independent Research Grant (MDACC IRG), and the Erickson Kidney Cancer Research Foundation. We would like to thank the Biostatistics Resource and the Small Animal Imaging Facility (SAIF) of MDACC for animal imaging assistance, especially Charles Kingsley, which obtain support from an NCI Cancer Center Support Grant (P30 CA016672). Financial support was also obtained from P50 CA221707 and U01 CA214263. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Funding Information:
This study was funded by the National Institutes of Health grant P50 CA94056 to the MD Anderson Cancer Center-Washington University Inter-Institutional Molecular Imaging Center, the Gerald Dewey Dodd, Jr, Endowed Distinguished Chair of the University of Texas MD Anderson Cancer Center, a faculty UT STARs Award, a University of Texas MD Anderson Cancer Center Independent Research Grant (MDACC IRG), and the Erickson Kidney Cancer Research Foundation. We would like to thank the Biostatistics Resource and the Small Animal Imaging Facility (SAIF) of MDACC for animal imaging assistance, especially Charles Kingsley, which obtain support from an NCI Cancer Center Support Grant (P30 CA016672). Financial support was also obtained from P50 CA221707 and U01 CA214263. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2021 THE AUTHORS.
PY - 2021/7/1
Y1 - 2021/7/1
N2 - Cellular pyruvate is an essential metabolite at the crossroads of glycolysis and oxidative phosphorylation, capable of supporting fermentative glycolysis by reduction to lactate mediated by lactate dehydrogenase (LDH) among other functions. Several inherited diseases of mitochondrial metabolism impact extracellular (plasma) pyruvate concentrations, and [1-13C]pyruvate infusion is used in isotope-labeled metabolic tracing studies, including hyperpolarized magnetic resonance spectroscopic imaging. However, how these extracellular pyruvate sources impact intracellular metabolism is not clear. Herein, we examined the effects of excess exogenous pyruvate on intracellular LDH activity, extracellular acidification rates (ECARs) as a measure of lactate production, and hyperpolarized [1-13C]py-ruvate-to-[1-13C]lactate conversion rates across a panel of tumor and normal cells. Combined LDH activity and LDHB/LDHA expression analysis intimated various heterotetrameric isoforms comprising LDHA and LDHB in tumor cells, not only canonical LDHA. Millimolar concentrations of exogenous pyruvate induced substrate inhibition of LDH activity in both enzymatic assays ex vivo and in live cells, abrogated glycolytic ECAR, and inhibited hyperpolarized [1-13C]pyruvate-to-[1-13C]lactate conversion rates in cellulo. Of importance, the extent of exogenous pyruvate-induced inhibition of LDH and glycolytic ECAR in live cells was highly dependent on pyruvate influx, functionally mediated by monocarboxylate transporter-1 localized to the plasma membrane. These data provided evidence that highly concentrated bolus injections of pyruvate in vivo may transiently inhibit LDH activity in a tissue type- and monocarboxylate transporter-1–dependent manner. Maintaining plasma pyruvate at submillimolar concentrations could potentially minimize transient metabolic perturbations, improve pyruvate therapy, and enhance quantification of metabolic studies, including hyperpolarized [1-13C]pyruvate magnetic resonance spectroscopic imaging and stable isotope tracer experiments.
AB - Cellular pyruvate is an essential metabolite at the crossroads of glycolysis and oxidative phosphorylation, capable of supporting fermentative glycolysis by reduction to lactate mediated by lactate dehydrogenase (LDH) among other functions. Several inherited diseases of mitochondrial metabolism impact extracellular (plasma) pyruvate concentrations, and [1-13C]pyruvate infusion is used in isotope-labeled metabolic tracing studies, including hyperpolarized magnetic resonance spectroscopic imaging. However, how these extracellular pyruvate sources impact intracellular metabolism is not clear. Herein, we examined the effects of excess exogenous pyruvate on intracellular LDH activity, extracellular acidification rates (ECARs) as a measure of lactate production, and hyperpolarized [1-13C]py-ruvate-to-[1-13C]lactate conversion rates across a panel of tumor and normal cells. Combined LDH activity and LDHB/LDHA expression analysis intimated various heterotetrameric isoforms comprising LDHA and LDHB in tumor cells, not only canonical LDHA. Millimolar concentrations of exogenous pyruvate induced substrate inhibition of LDH activity in both enzymatic assays ex vivo and in live cells, abrogated glycolytic ECAR, and inhibited hyperpolarized [1-13C]pyruvate-to-[1-13C]lactate conversion rates in cellulo. Of importance, the extent of exogenous pyruvate-induced inhibition of LDH and glycolytic ECAR in live cells was highly dependent on pyruvate influx, functionally mediated by monocarboxylate transporter-1 localized to the plasma membrane. These data provided evidence that highly concentrated bolus injections of pyruvate in vivo may transiently inhibit LDH activity in a tissue type- and monocarboxylate transporter-1–dependent manner. Maintaining plasma pyruvate at submillimolar concentrations could potentially minimize transient metabolic perturbations, improve pyruvate therapy, and enhance quantification of metabolic studies, including hyperpolarized [1-13C]pyruvate magnetic resonance spectroscopic imaging and stable isotope tracer experiments.
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U2 - 10.1016/j.jbc.2021.100775
DO - 10.1016/j.jbc.2021.100775
M3 - Article
C2 - 34022218
AN - SCOPUS:85108709020
SN - 0021-9258
VL - 297
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 1
M1 - 100775
ER -