scholarly journals Mitochondrial NADP(H) generation is essential for proline biosynthesis

Science ◽  
2021 ◽  
pp. eabd5491
Author(s):  
Jiajun Zhu ◽  
Simon Schwörer ◽  
Mirela Berisa ◽  
Yeon Ju Kyung ◽  
Keun Woo Ryu ◽  
...  

The coenzyme nicotinamide adenine dinucleotide phosphate (NADP+) and its reduced form (NADPH) regulate reductive metabolism in a subcellularly compartmentalized manner. Mitochondrial NADP(H) production depends on the phosphorylation of NAD(H) by NAD kinase 2 (NADK2). Deletion of NADK2 in human cell lines did not alter mitochondrial folate pathway activity, tricarboxylic acid cycle activity, or mitochondrial oxidative stress, but led to impaired cell proliferation in minimal medium. This growth defect was rescued by proline supplementation. NADK2-mediated mitochondrial NADP(H) generation was required for the reduction of glutamate and hence proline biosynthesis. Furthermore, mitochondrial NADP(H) availability determined the production of collagen proteins by cells of mesenchymal lineage. Thus, a primary function of the mitochondrial NADP(H) pool is to support proline biosynthesis for use in cytosolic protein synthesis.

2012 ◽  
Vol 93 (4) ◽  
pp. 580-584
Author(s):  
I V Sergeeva ◽  
N I Kamzalakova ◽  
E P Tikhonova ◽  
G V Bulygin

Aim. To assess the nature and intensity of metabolic processes in lymphocytes of patients with influenza according to the activity of intracellular enzymes in comparison to the severity of the disease. Methods. Determined were the enzymatic parameters of lymphocytes of 45 patients aged 18 to 42 years with a diagnosis of «influenza». Two groups of patients were formed: with moderate (24 patients) and severe (21 patients) course of the disease. Used as controls were the values the activity of intracellular enzymes of lymphocytes of 37 practically healthy individuals of comparable age. Results. In patients with a moderately severe course of the influenza compared with the controls noted was a significant increase in activity of glucose-6-phosphate dehydrogenase (3.17±0.53 and 2.74±0.31 mkE/10 000 cells, p 0.05) and glycerol-3-phosphate dehydrogenase (57.33±±5.65 and 0.84±0.16 mkE/10 000 cells respectively, p 0.001). The activity of lactate dehydrogenase was lower in patients than in controls (0.40±0.08 and 0.84±0.08 mkE/10 000 cells respectively, p 0.001). Indicators of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate dependant isocitrate dehydrogenases in lymphocytes of patients were lower than in the controls: the first indicator in the patients was 0.17±0.02 mkE/10 000 cells, in controls - 1.95±0.25 mkE/10 000 cells (p 0.001), and for the second indicator these values were respectively 0.09±0.01 and 31.02±±2.20 mkE/10 000 cells (p 0.001). In patients with a moderately severe course of influenza the activity of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate dependant glutamate dehydrogenases was significantly higher compared with healthy individuals: 63.67±5.32 and 0.34±0.06 mkE/10 000 cells, 1.45±0.18 and 0.11±0.02 mkE/10 000 cells respectively (p 0.001). The activity of nicotinamide adenine dinucleotide dependant malate dehydrogenase in patients was equal to 86.46±12.30 mkE/10 000 cells (in the control group 84.16±13.70 mkE/10 000 cells), and the activity of nicotinamide adenine dinucleotide phosphate dependant malate dehydrogenase was equal to 1.34±±0.25 mkE/10 000 cells (in the control group 0.33±0.07 mkE/10 000 cells, p 0.001). The activity of glutathione reductase was also higher in patients with the moderately severe course of the influenza: 5.86±0.25 mkE/10 000 cells, while the value in healthy individuals was 1.28±0.30 mkE/10 000 cells (p 0.001). In the group of patients with a severe course of influenza the activity of almost all (except for glucose-6-phosphate dehydrogenase) enzymes was higher than during the moderately severe course of disease. Conclusion. At the peak of the diseases noted were opposite changes in the activity of reactions of the pentose phosphate cycle and glycolysis. With a high functional load on the cells there is a significant reduction in the intensity of the reactions of the initial phase of the tricarboxylic acid cycle, which reduces the energy efficiency of the cycle, while the intense influx of metabolites to supply the tricarboxylic acid cycle with substrates of the amino acid metabolism provides enhanced transport of amino acids into the lymphocytes.


2015 ◽  
Vol 35 (9) ◽  
pp. 1494-1506 ◽  
Author(s):  
Nikolaus Berndt ◽  
Oliver Kann ◽  
Hermann-Georg Holzhütter

Imaging of the cellular fluorescence of the reduced form of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) is one of the few metabolic readouts that enable noninvasive and time-resolved monitoring of the functional status of mitochondria in neuronal tissues. Stimulation-induced transient changes in NAD(P)H fluorescence intensity frequently display a biphasic characteristic that is influenced by various molecular processes, e.g., intracellular calcium dynamics, tricarboxylic acid cycle activity, the malate–aspartate shuttle, the glycerol-3-phosphate shuttle, oxygen supply or adenosine triphosphate (ATP) demand. To evaluate the relative impact of these processes, we developed and validated a detailed physiologic mathematical model of the energy metabolism of neuronal cells and used the model to simulate metabolic changes of single cells and tissue slices under different settings of stimulus-induced activity and varying nutritional supply of glucose, pyruvate or lactate. Notably, all experimentally determined NAD(P)H responses could be reproduced with one and the same generic cellular model. Our computations reveal that (1) cells with quite different metabolic status may generate almost identical NAD(P)H responses and (2) cells of the same type may quite differently contribute to aggregate NAD(P)H responses recorded in brain slices, depending on the spatial location within the tissue. Our computational approach reconciles different and sometimes even controversial experimental findings and improves our mechanistic understanding of the metabolic changes underlying live-cell NAD(P)H fluorescence transients.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yiyong Wei ◽  
Donghang Zhang ◽  
Jin Liu ◽  
Mengchan Ou ◽  
Peng Liang ◽  
...  

Abstract Background Metabolic status can be impacted by general anesthesia and surgery. However, the exact effects of general anesthesia and surgery on systemic metabolome remain unclear, which might contribute to postoperative outcomes. Methods Five hundred patients who underwent abdominal surgery were included. General anesthesia was mainly maintained with sevoflurane. The end-tidal sevoflurane concentration (ETsevo) was adjusted to maintain BIS (Bispectral index) value between 40 and 60. The mean ETsevo from 20 min after endotracheal intubation to 2 h after the beginning of surgery was calculated for each patient. The patients were further divided into low ETsevo group (mean − SD) and high ETsevo group (mean + SD) to investigate the possible metabolic changes relevant to the amount of sevoflurane exposure. Results The mean ETsevo of the 500 patients was 1.60% ± 0.34%. Patients with low ETsevo (n = 55) and high ETsevo (n = 59) were selected for metabolomic analysis (1.06% ± 0.13% vs. 2.17% ± 0.16%, P < 0.001). Sevoflurane and abdominal surgery disturbed the tricarboxylic acid cycle as identified by increased citrate and cis-aconitate levels and impacted glycometabolism as identified by increased sucrose and D-glucose levels in these 114 patients. Glutamate metabolism was also impacted by sevoflurane and abdominal surgery in all the patients. In the patients with high ETsevo, levels of L-glutamine, pyroglutamic acid, sphinganine and L-selenocysteine after sevoflurane anesthesia and abdominal surgery were significantly higher than those of the patients with low ETsevo, suggesting that these metabolic changes might be relevant to the amount of sevoflurane exposure. Conclusions Sevoflurane anesthesia and abdominal surgery can impact principal metabolic pathways in clinical patients including tricarboxylic acid cycle, glycometabolism and glutamate metabolism. This study may provide a resource data for future studies about metabolism relevant to general anaesthesia and surgeries. Trial registration www.chictr.org.cn. identifier: ChiCTR1800014327.


2013 ◽  
Vol 129 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Mussie G. Hadera ◽  
Olav B. Smeland ◽  
Tanya S. McDonald ◽  
Kah Ni Tan ◽  
Ursula Sonnewald ◽  
...  

1951 ◽  
Vol 190 (2) ◽  
pp. 853-858
Author(s):  
Jack J.R. Campbell ◽  
Flora.Norris. Stokes

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