Identification of a novel malonyl-CoA IC50 for CPT-I: implications for predicting <i>in vivo</i> fatty acid oxidation rates

Smith, Brennan K.; Perry, Christopher G. R.; Koves, Timothy R.; Wright, David C.; Smith, Jeffrey C.; Neufer, P. Darrell; Muoio, Deborah M.; Holloway, Graham P.

doi:10.1042/bj20121110

Cited by 37 publications

(28 citation statements)

References 60 publications

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“…These tests included either the measurement of total CPT activity given as the sum of both transporters CPT1 and CPT2, or the use of radio‐labeled substrates and spectroscopy . In line with a previous report, we suppose that the enzyme activity shown in this work reflects mostly the CPT2 activity, since the addition of malonyl‐CoA as strong CPT1 inhibitor did not reduce the transacylation rate measured in patients and healthy controls. Moreover, CPT1 accounts only for less than 15% of the total CPT activity and therefore may not play a role under the described assay conditions.…”

Section: Discussionsupporting

confidence: 82%

Implementation of a fast method for the measurement of carnitine palmitoyltransferase 2 activity in lymphocytes by tandem mass spectrometry as confirmation for newborn screening

Tucci

Behringer

Sturm

et al. 2019

J of Inher Metab Disea

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Carnitine palmitoyltransferase II (CPT2) is a rare autosomal recessive inherited disorder affecting mitochondrial β‐oxidation. Confirmation diagnostics are mostly based on molecular sequencing of the CPT2 gene, especially to distinguish CPT2 and carnitine:aclycarnitine translocase deficiencies, which present with identical acylcarnitine profiles on newborn screening (NBS). In the past, different enzyme tests in muscle biopsies have been developed in order to study the functional effect in one of the main target organs. In this study, we implemented a method for measurement of CPT2 enzyme activity in human lymphocytes with detection of the reaction products via liquid chromatography mass spectrometry to enable the simultaneous evaluation of the functional impairment and the clear diagnosis of the disease. CPT2 activity was measured in samples collected from CPT2 patients (n = 11), heterozygous carriers (n = 6), and healthy individuals (n = 52). Seven patients out of 11 were homozygous for the common mutation c.338T>C and showed a residual activity with median values of 19.2 ± 3.7% of healthy controls. Heterozygous carriers showed a residual activity in the range of 42% to 75%. Four individuals carrying the heterozygous mutation c.338T>C showed a 2‐fold higher residual activity as compared to homozygous individuals. Our optimized method for the measurement of CPT2 activity is able to clearly discriminate between patients and healthy individuals and offers the possibility to determine CPT2 activity in human lymphocytes avoiding the need of an invasive muscle biopsy. This method can be successfully used for confirmation diagnosis in case of positive NBS and would markedly reduce the time to define diagnosis.

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Section: Discussionsupporting

confidence: 82%

Implementation of a fast method for the measurement of carnitine palmitoyltransferase 2 activity in lymphocytes by tandem mass spectrometry as confirmation for newborn screening

Tucci

Behringer

Sturm

et al. 2019

J of Inher Metab Disea

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“…This is contrary to the known preference of the adult heart for fatty acid oxidation. A recent study by Smith et al 73 in skeletal muscle suggests that the IC 50 for malonyl CoA inhibition of CPT1 is an order of magnitude greater in permeabilized muscle fibers compared with isolated mitochondria, and the IC 50 increases with increased palmitoyl CoA concentration. This work suggests that high intracellular levels of fatty acyl CoA can compete with malonyl CoA to reduce CPT1 inhibition and may require us to re-evaluate how we interpret steady-state levels of malonyl CoA.…”

Section: Mitochondrial Metabolite Transportersmentioning

confidence: 97%

“…71 The activity of CPT1 is inhibited by the concentration of malonyl CoA in vitro; however, the in vivo relationship between the concentration of malonyl CoA and CPT1 activity is more complicated. The IC 50 for muscle CPT1 inhibition by malonyl CoA is much lower than the intracellular concentration of malonyl CoA, 72,73 suggesting that CPT1 would be largely inhibited under normal conditions. This is contrary to the known preference of the adult heart for fatty acid oxidation.…”

Section: Mitochondrial Metabolite Transportersmentioning

confidence: 98%

Matrix Revisited

Carley

Taegtmeyer

Lewandowski

2014

Circulation Research

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Metabolic signaling mechanisms are increasingly recognized to mediate the cellular response to alterations in workload demand, as a consequence of physiological and pathophysiological challenges. Thus, an understanding of the metabolic mechanisms coordinating activity in the cytosol with the energy-providing pathways in the mitochondrial matrix becomes critical for deepening our insights into the pathogenic changes that occur in the stressed cardiomyocyte. Processes that exchange both metabolic intermediates and cations between the cytosol and mitochondria enable transduction of dynamic changes in contractile state to the mitochondrial compartment of the cell. Disruption of such metabolic transduction pathways has severe consequences for the energetic support of contractile function in the heart and is implicated in the pathogenesis of heart failure. Deficiencies in metabolic reserve and impaired metabolic transduction in the cardiomyocyte can result from inherent deficiencies in metabolic phenotype or maladaptive changes in metabolic enzyme expression and regulation in the response to pathogenic stress. This review examines both current and emerging concepts of the functional linkage between the cytosol and the mitochondrial matrix with a specific focus on metabolic reserve and energetic efficiency. These principles of exchange and transport mechanisms across the mitochondrial membrane are reviewed for the failing heart from the perspectives of chronic pressure overload and diabetes mellitus.

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“…These findings suggest that during muscle contractions and/or exercise, the concentration of malonyl‐CoA is not vital for controlling mitochondrial FA flux; a concept observed in a recent report detailing insensitivity of mitochondrial FA oxidation to malonyl‐CoA in permeabilized muscle fibres (Smith et al . ).…”

Section: Introductionmentioning

confidence: 97%

The role of AMPK in controlling metabolism and mitochondrial biogenesis during exercise

Marcinko

Steinberg

2014

Experimental Physiology

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New Findings r What is the topic of this review?The topic of this review is the metabolic effects of AMP-activated protein kinase (AMPK) on glucose and fatty acid (FA) uptake, FA oxidation and mitochondrial biogenesis in skeletal muscle at rest and during exercise/muscle contractions. r What advances does it highlight?This review describes recent studies examining the molecular mechanisms by which AMPK regulates muscle metabolism. It specifically discusses the role of exercise on acetyl-CoA carboxylase and malonyl-CoA in the regulation of FA oxidation. It also discusses the role of AMPK in regulating glucose and FA uptake during exercise. Finally, the review describes the interaction between AMPK, peroxisome proliferator-activated receptor γ co-activator-1α and sirtuin 1 in controlling mitochondrial biogenesis.Insulin resistance is associated with defects in skeletal muscle fatty acid (FA) metabolism that contribute to the development of type 2 diabetes. Endurance exercise increases FA and glucose metabolism, muscle mitochondrial content and insulin sensitivity. In skeletal muscle, basal rates of FA oxidation are dependent on AMP-activated protein kinase (AMPK) phosphorylation of acetyl-CoA carboxylase 2, the rate-limiting enzyme controlling the production of the metabolic intermediate malonyl-CoA. Likewise, AMPK is essential for maintaining muscle mitochondrial content in untrained mice; effects that may be mediated through regulation of the peroxisome proliferator-activated receptor γ co-activator-1α. However, the importance of AMPK in regulating glucose and FA uptake, FA oxidation and mitochondrial biogenesis during and following endurance exercise training is not fully understood. A better understanding of the mechanisms by which endurance exercise regulates substrate utilization and mitochondrial biogenesis may lead to improved therapeutic and preventative strategies for the treatment of insulin resistance and type 2 diabetes.

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Identification of a novel malonyl-CoA IC50 for CPT-I: implications for predicting in vivo fatty acid oxidation rates

Cited by 37 publications

References 60 publications

Implementation of a fast method for the measurement of carnitine palmitoyltransferase 2 activity in lymphocytes by tandem mass spectrometry as confirmation for newborn screening

Implementation of a fast method for the measurement of carnitine palmitoyltransferase 2 activity in lymphocytes by tandem mass spectrometry as confirmation for newborn screening

Matrix Revisited

The role of AMPK in controlling metabolism and mitochondrial biogenesis during exercise

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