scholarly journals MCART1 is required for mitochondrial NAD transport

2020 ◽  
Author(s):  
Nora Kory ◽  
Jelmi uit de Bos ◽  
Sanne van der Rijt ◽  
Nevena Jankovic ◽  
Miriam Güra ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Tca Cycle ◽  
Substrate Oxidation ◽  
Isolated Mitochondria ◽  
Mitochondrial Transporter ◽  
Transport Chain ◽  
Atp Generation ◽  
Higher Eukaryotes ◽  
Complex I Activity

AbstractThe nicotinamide adenine dinucleotide (NAD+/NADH) pair is a cofactor in redox reactions and is particularly critical in mitochondria as it connects substrate oxidation by the tricarboxylic acid (TCA) cycle to ATP generation by the electron transport chain (ETC) and oxidative phosphorylation. While a mitochondrial NAD+ transporter has been identified in yeast, how NAD enters mitochondria in higher eukaryotes is unknown. Here, we mine gene essentiality data from human cell lines to identify MCART1 (SLC25A51) as co-essential with ETC components. MCART1-null cells have large decreases in TCA cycle flux, mitochondrial respiration, ETC complex I activity, and mitochondrial levels of NAD+ and NADH. Isolated mitochondria from cells lacking or overexpressing MCART1 have greatly decreased or increased NAD uptake in vitro, respectively. Moreover, MCART1 and NDT1, a yeast mitochondrial NAD+ transporter, can functionally complement for each other. Thus, we propose that MCART1 is the long sought mitochondrial transporter for NAD in human cells.

scholarly journals MCART1/SLC25A51 is required for mitochondrial NAD transport

2020 ◽  
Vol 6 (43) ◽  
pp. eabe5310 ◽  
Author(s):  
Nora Kory ◽  
Jelmi uit de Bos ◽  
Sanne van der Rijt ◽  
Nevena Jankovic ◽  
Miriam Güra ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Redox Reactions ◽  
Tca Cycle ◽  
Substrate Oxidation ◽  
Tricarboxylic Acid ◽  
Isolated Mitochondria ◽  
Mitochondrial Transporter ◽  
Transport Chain ◽  
Complex I Activity

The nicotinamide adenine dinucleotide (NAD+/NADH) pair is a cofactor in redox reactions and is particularly critical in mitochondria as it connects substrate oxidation by the tricarboxylic acid (TCA) cycle to adenosine triphosphate generation by the electron transport chain (ETC) and oxidative phosphorylation. While a mitochondrial NAD+ transporter has been identified in yeast, how NAD enters mitochondria in metazoans is unknown. Here, we mine gene essentiality data from human cell lines to identify MCART1 (SLC25A51) as coessential with ETC components. MCART1-null cells have large decreases in TCA cycle flux, mitochondrial respiration, ETC complex I activity, and mitochondrial levels of NAD+ and NADH. Isolated mitochondria from cells lacking or overexpressing MCART1 have greatly decreased or increased NAD uptake in vitro, respectively. Moreover, MCART1 and NDT1, a yeast mitochondrial NAD+ transporter, can functionally complement for each other. Thus, we propose that MCART1 is the long sought mitochondrial transporter for NAD in human cells.

scholarly journals Impaired Mitochondrial Function Results from Oxidative Stress in the Full-Term Placenta of Sows with Excessive Back-Fat

Animals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 360 ◽  
Author(s):  
Liang Tian ◽  
Jiahe Huang ◽  
Aiyou Wen ◽  
Peishi Yan
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Function ◽  
Placental Tissue ◽  
Term Placenta ◽  
Mitochondrial Alterations ◽  
Transport Chain ◽  
Elevated Protein ◽  
Atp Generation ◽  
Complex I Activity

The aim of this study was to determine the effect of excessive back-fat (BF) of sows on placental oxidative stress, ATP generation, mitochondrial alterations in content and structure, and mitochondrial function in isolated trophoblasts. Placental tissue was collected by vaginal delivery from BFI (15–20 mm, n = 10) and BFII (21–27 mm, n = 10) sows formed according to BF at mating. Our results demonstrated that excessive back-fat contributed to augmented oxidative stress in term placenta, as evidenced by excessive production of ROS, elevated protein carbonylation, and reduced SOD, GSH-PX, and CAT activities (p < 0.05). Indicative of mitochondrial dysfunction, reduced mitochondrial respiration in cultured trophoblasts was linked to decreased ATP generation, lower mitochondrial Complex I activity and reduced expression of electron transport chain subunits in placenta of BFII sows (p < 0.05). Meanwhile, we observed negative alterations in mitochondrial biogenesis and structure in the placenta from BFII group (p < 0.05). Finally, our in vitro studies showed lipid-induced ROS production resulted in mitochondrial alterations in trophoblasts, and these effects were blocked by antioxidant treatment. Together, these data reveal that excessive back-fat aggravates mitochondrial injury induced by increased oxidative stress in pig term placenta, which may have detrimental consequences on placental function and therefore impaired fetal growth and development.

Alterations of Hepatic Microsomal Drug Metabolism by Glucagon

1975 ◽  
Vol 53 (5) ◽  
pp. 873-879 ◽  
Author(s):  
Jacob V. Aranda ◽  
Kenneth W. Renton
Keyword(s):  
Substrate Oxidation ◽  
Type I ◽  
Nadph Cytochrome ◽  
Transport Chain ◽  
Hexobarbital Sleeping Time ◽  
Nadph Oxidation ◽  
In Vivo Effects ◽  
Cytochrome P 450

The effect of glucagon on the components of the hepatic microsomal electron transport chain (NADPH oxidase, NADPH cytochrome c reductase (EC 1.6.2.4), cytochrome P-450, and NADPH cytochrome P-450 reductase), and on two representative oxidative pathways (aminopyrine N-demethylation, a type I substrate oxidation; and aniline p-hydroxylation, a type II substrate oxidation) was determined. Microsomes from rats pretreated with glucagon (300 μg/kg per day for 3 days) showed a significant decrease in NADPH oxidation and in aminopyrine N-demethylation with a prolonged hexobarbital sleeping time, and a significant increase in aniline p-hydroxylation. Microsomes from rats pretreated with a lower dose of glucagon (30 μg/kg per day for 3 days) showed a significant decrease in the microsomal N-demethylation of aminopyrine. Glucagon had no effect when added in vitro to microsomes, suggesting that the in vivo effects of glucagon are mediated indirectly in the intact animal.

scholarly journals Inhibition of Mitochondrial Complex III in Candida Albicans ADH1 Deletion Mutant Attenuates Its Pathogenicity Significantly

2021 ◽  
Author(s):  
Hui Guo ◽  
Yi Shan Zhang ◽  
Yan Jun Song ◽  
Ya Jing Zhao ◽  
Shui Xiu Li ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Alternative Oxidase ◽  
Oxidase Inhibitor ◽  
Complex Iii ◽  
Ros Production ◽  
Mitochondrial Complex ◽  
Aerobic Growth ◽  
Transport Chain ◽  
Atp Generation

Abstract Fermentation and aerobic respiration in mitochondria are coordinately regulated and compensated either when C. albicans grows in vitro or in the hosts, and the creature gain the strong viability. It’s insufficient to influent the growth, reproduction and pathogenicity of C. albicans by inhibiting the electron transport chain (ECT) CI, CII, CIII, CV, or fermentation related gene ADH1. Our study showed that the induction of AA (inhibitor of complex III) rather than SHAM (alternative oxidase inhibitor) abolishes the mitochondrial function completely （96% less ATP generation, 59% reduction in MMP), and increases ROS production significantly in ADH1-deleted mutant ( adh1Δ/ adh1Δ ) that in turn becomes hypersensitive to azole and apoptosis, less viable and more difficult to form hyphae. At the same time, the expression of virulence related genes ALS3 and HWP1 were significantly lower than that of WT under AA induction. Under the induction of AA, the mitochondrial function of WT was slightly damaged and cell apoptosis increased slightly，ROS production and sensitivity of azoles increased significantly, but mycelium formation and the growth of cells were not affected. Under aerobic growth, we observed an ADH1 - dependent mitochondrial effect in C. albicans demonstrated by 64% less ATP generation, 58% reduction in MMP and significant elevations of the ROS and apoptosis in ADH1 -deleted mutant. However, mycelium formation and azole susceptibility are not affected. Our results suggested that ADH1 plus CIII played an important role in antifungal activity by damaging mitochondrial function, inhibiting cell growth and hyphae formation, promoting apoptosis and reducing pathogenicity.

scholarly journals Asparagine signals mitochondrial respiration and can be targeted to impair tumour growth

2020 ◽  
Author(s):  
Abigail S. Krall ◽  
Peter J. Mullen ◽  
Felicia Surjono ◽  
Milica Momcilovic ◽  
Ernst W. Schmid ◽  
...  
Keyword(s):  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Tumour Growth ◽  
Therapeutic Strategy ◽  
Tca Cycle ◽  
Nucleotide Synthesis ◽  
Transport Chain ◽  
Mouse Models Of Cancer

AbstractMitochondrial respiration is critical for cell proliferation. In addition to producing ATP via the electron transport chain (ETC), respiration is required for the generation of TCA cycle-derived biosynthetic precursors, such as aspartate, an essential substrate for nucleotide synthesis. Because mTORC1 coordinates availability of biosynthetic precursors with anabolic metabolism, including nucleotide synthesis, a link between respiration and mTORC1 is fitting. Here we show that in addition to depleting intracellular aspartate, ETC inhibition depletes aspartate-derived asparagine and impairs mTORC1 activity. Providing exogenous asparagine restores mTORC1 activity, nucleotide synthesis, and proliferation in the context of ETC inhibition without restoring intracellular aspartate in a panel of cancer cell lines. As a therapeutic strategy, the combination of ETC inhibitor metformin, which limits tumour asparagine synthesis, and either asparaginase or dietary asparagine restriction, which limit tumour asparagine consumption, effectively impairs tumour growth in several mouse models of cancer. Because environmental asparagine is sufficient to restore proliferation with respiration impairment, both in vitro and in vivo, our findings suggest that asparagine synthesis is a fundamental purpose of mitochondrial respiration. Moreover, the results suggest that asparagine signals active respiration to mTORC1 to communicate biosynthetic precursor sufficiency and promote anabolism.

scholarly journals Anemoside B4 ameliorates TNBS-induced colitis through S100A9/MAPK/NF-κB signaling pathway

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yong Zhang ◽  
Zhengxia Zha ◽  
Wenhua Shen ◽  
Dan Li ◽  
Naixin Kang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Signaling Pathway ◽  
Tca Cycle ◽  
Mapk Signaling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Trinitrobenzene Sulfonic Acid ◽  
Therapeutic Effects ◽  
Triterpenoid Saponin ◽  
Label Free

Abstract Background Despite the increased morbidity of ulcerative colitis (UC) in the developing countries, available treatments remain unsatisfactory. Therefore, it is urgent to discover more effective therapeutic strategies. Pulsatilla chinensis was widely used for the treatment of inflamed intestinal diseases including UC for thousands of years in China. Anemoside B4, the most abundant triterpenoid saponin isolated from P. chinensis, exerts anti-inflammatory and antioxidant effects and may be the most active compounds, which is responsible for the therapeutic effects. However, the mechanism how anemoside B4 executes its biological functions is still elusive. Methods Here, we used the 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model to evaluate the therapeutic effect of anemoside B4. Blood samples of colitis rats were collected for hematology analysis. The inflammation-associated factors were investigated by enzyme-linked immunosorbent assay (ELISA). Cell proliferation and apoptosis was determined with EdU cell proliferation assay and TUNEL assay. The proteins regulated by anemoside B4 were identified by label-free quantitative proteomics. The significantly down-regulated proteins were verified by Western blotting analysis. mRNA expression was analyzed by quantitative real-time RT-PCR. Results The results showed that anemoside B4 ameliorated TNBS-induced colitis symptoms, including tissue damage, inflammatory cell infiltration, and pro-inflammatory cytokine production, apoptosis and slowed proliferation in colon. Quantitative proteomic analyses discovered that 56 proteins were significantly altered by anemoside B4 in the TNBS-induced rats. These proteins mainly clustered in tricarboxylic acid (TCA) cycle and respiratory electron transport chain. Among the altered proteins, S100A9 is one of the most significantly down-regulated proteins and associated with NF-κB and MAPK signaling pathways in the pathogenesis of UC. Further experiments revealed that anemoside B4 suppressed the expression of S100A9 and its downstream genes including TLR4 and NF-κB in colon. In vitro, anemoside B4 could inhibit the NF-κB signaling pathway induced by recombinant S100A9 protein in human intestinal epithelial Caco-2 cells. Moreover, anemoside B4 inhibits neutrophils recruitment and activation in colon induced by TNBS. Conclusions Our results demonstrate that anemoside B4 prevents TNBS-induced colitis by inhibiting the NF-κB signaling pathway through deactivating S100A9, suggesting that anemoside B4 is a promising therapeutic candidate for colitis.

scholarly journals Ferroptosis contributes to isoflurane-induced neurotoxicity and learning and memory impairment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pengfei Liu ◽  
Jing Yuan ◽  
Yetong Feng ◽  
Xin Chen ◽  
Guangsuo Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Learning And Memory ◽  
Memory Impairment ◽  
Close Association ◽  
Dimethyl Fumarate ◽  
Dependent Manner ◽  
Transport Chain ◽  
The Relationship

AbstractFerroptosis is a novel type of programmed cell death, which is different from apoptosis and autophagic cell death. Recently, ferroptosis has been indicated to contribute to the in vitro neurotoxicity induced by isoflurane, which is one of the most common anesthetics in clinic. However, the in vivo position of ferroptosis in isoflurane-induced neurotoxicity as well as learning and memory impairment remains unclear. In this study, we mainly explored the relationship between ferroptosis and isoflurane-induced learning and memory, as well as the therapeutic methods in mouse model. Our results indicated that isoflurane induced the ferroptosis in a dose-dependent and time-dependent manner in hippocampus, the organ related with learning and memory ability. In addition, the activity of cytochrome c oxidase/Complex IV in mitochondrial electron transport chain (ETC) was increased by isoflurane, which might further contributed to cysteine deprivation-induced ferroptosis caused by isoflurane exposure. More importantly, isoflurane-induced ferroptosis could be rescued by both ferroptosis inhibitor (ferrostatin-1) and mitochondria activator (dimethyl fumarate), which also showed effective therapeutic action against isoflurane-induced learning and memory impairment. Taken together, our data indicate the close association among ferroptosis, mitochondria and isoflurane, and provide a novel insight into the therapy mode against isoflurane-induced learning and memory impairment.

scholarly journals Studies on the Mechanism by Which Anaerobiosis Prevents Swelling of Mitochondria in Vitro: Effect of Electron Transport Chain Inhibitors

1959 ◽  
Vol 234 (8) ◽  
pp. 2176-2186 ◽  
Author(s):  
F. Edmund Hunter ◽  
Jerome F. Levy ◽  
Joan Fink ◽  
Beverly Schutz ◽  
Francisco Guerra ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Transport Chain ◽  
Vitro Effect

Reduced substrate oxidation in postischemic myocardium: 13C and 31P NMR analyses

1990 ◽  
Vol 258 (5) ◽  
pp. H1357-H1365 ◽  
Author(s):  
E. D. Lewandowski ◽  
D. L. Johnston
Keyword(s):  
Steady State ◽  
31P Nmr ◽  
Tca Cycle ◽  
High Energy ◽  
Substrate Oxidation ◽  
High Energy Phosphates ◽  
Atp Content ◽  
And Control ◽  
13C And 31P Nmr ◽  
Postischemic Myocardium

13C and 31P nuclear magnetic resonance (NMR) spectra were used to assess substrate oxidation and high-energy phosphates in postischemic (PI) isolated rabbit hearts. Phosphocreatine (PCr) increased in nonischemic controls on switching from glucose perfusion to either 2.5 mM [3-13C]pyruvate (120%, n = 7) or [2-13C]acetate (114%, n = 8, P less than 0.05). ATP content, oxygen consumption (MVO2), and hemodynamics (dP/dt) were not affected by substrate availability in control or PI hearts. dP/dt was 40-60% lower in PI hearts during reperfusion after 10 min ischemia. Hearts reperfused with either pyruvate (n = 11) or acetate (n = 8) regained preischemic PCr levels within 45 s. Steady-state ATP levels were 55-70% of preischemia with pyruvate and 52-60% with acetate. Percent maximum [4-13C]glutamate signal showed reduced conversion of pyruvate to glutamate via the tricarboxylic acid (TCA) cycle at 4-min reperfusion (PI = 24 +/- 4%, means +/- SE; Control = 48 +/- 4%). The increase in 13C signal from the C-4 position of glutamate was similar to control hearts within 10.5 min. The increase in [4-13C]glutamate signal from acetate was not different between PI and control hearts. The ratio of [2-13C]Glu:[4-13C]Glu, reflecting TCA cycle activity, was reduced in PI hearts with acetate for at least 10 min (Control = 0.76 +/- 0.03; PI = 0.51 +/- 0.09) until steady state was reached. Despite rapid recovery of oxidative phosphorylation, contractility remained impaired and substrate oxidation was significantly slowed in postischemic hearts.

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