Abstract 13357: Dhtkd1 Knock-out Alters Cellular Respiration by Preventing Electron Transport Chain Related Proteins From Entering Into Mitochondria

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Chuan Wang ◽  
Holly Smith ◽  
Jane Ferguson
Keyword(s):  
Electron Transport ◽  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Cellular Metabolism ◽  
Cellular Respiration ◽  
Mitochondrial Energy Metabolism ◽  
Knock Out ◽  
Transport Chain ◽  
Related Proteins

The metabolite α-aminoadipic acid (2-AAA) has been identified as a predictor of diabetes and atherosclerosis in large human prospective studies. However, the mechanisms linking this metabolite to disease pathophysiology remain unknown. DHTKD1 is a central gene in the 2-AAA pathway, and has been linked to variation in 2-AAA levels in humans and animals. However, little is known about the role of DHTKD1 in cellular metabolism. We hypothesized that DHTKD1 is an important regulator of mitochondrial energy metabolism, with potential involvement in cardiometablic disease. Methods and Results: We investigated the consequences of loss of DHTKD1 function in a human HAP-1 cell line. Treatment with 2-AAA increased mitochondrial respiration in wild-type (WT) cells, but had no effect in DHTKD1 knock-out (KO) cells. DHTKD1 KO cells had significantly lower mitochondrial respiration (Mito Stress Test, Seahorse Analyzer), with no differences in glycolytic function, supporting an important role for DHTKD1 in mitochondrial metabolism. Membrane potential and mitochondrial content were up-regulated in KO compared to WT cells, suggesting a potential compensatory mechanism. We investigated the mechanisms underlying impaired mitochondrial function, and found TOM40 and TIM23, the pivotal proteins required for the movement of proteins into mitochondria, were decreased in DHTKD1 KO cells. Further, DHTKD1 KO resulted in reduced expression of electron transport chain related proteins (NDUF88, SDHB, MTCO1, UQCRC2, ATP5A) in mitochondria, but increased expression in the cytosol, suggesting impaired ability to cross the mitochondrial membrane. Conclusions: Our data suggest that the absence of DHTKD1 leads to less TOM40 and TIM23 expression, preventing key proteins in the electron transport chain from entering into mitochondria, resulting in impaired mitochondrial respiration. These findings highlight the vital role of DHTKD1 in cellular metabolism, and establish DHTKD1-mediated mitochondrial dysfunction as a potential novel pathway in cardiometabolic disease. Elevated 2-AAA observed in individuals prior to onset of diabetes and atherosclerosis may be an early biomarker of dysfunction in this pathway.

scholarly journals Human herpesvirus 1 protein US3 induces an inhibition of mitochondrial electron transport

2006 ◽  
Vol 87 (8) ◽  
pp. 2155-2159 ◽  
Author(s):  
Mohammad Derakhshan ◽  
Margaret M. Willcocks ◽  
Michael A. Salako ◽  
George E. N. Kass ◽  
Michael J. Carter
Keyword(s):  
Electron Transport ◽  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Human Herpesvirus ◽  
Cellular Respiration ◽  
Coxsackievirus B4 ◽  
Transport Chain ◽  
Phase Protein ◽  
Infected Cells ◽  
Herpesvirus 1

Previous studies have identified virus proteins that traffic to mitochondria and may affect mitochondrial function. Here, it is reported that Human herpesvirus 1 (HHV-1, herpes simplex virus 1) and influenza virus reduced mitochondrial respiration, whilst Measles virus, cytomegalovirus, coxsackievirus B4 and Feline calicivirus did not. The inhibition of total cellular respiration was caused by a block in the mitochondrial electron-transport chain. This effect occurred during β-phase protein synthesis and the inhibition of mitochondrial respiration could be reproduced by ectopic expression of the β-phase protein US3. An HHV-1 mutant lacking this protein failed to inhibit oxygen consumption in infected cells relative to controls. It was concluded that US3 was mediating the suppression of mitochondrial respiration following HHV-1 infection. The integrity of the electron-transport chain in HHV-1-infected cells was analysed further and the site of the block in electron transport was located between complexes II and III, a site previously shown to be affected by Poliovirus.

The Electron Transport Chain

2014 ◽  
Vol 76 (7) ◽  
pp. 456-458 ◽  
Author(s):  
Chris Romero ◽  
James Choun
Keyword(s):  
Electron Transport ◽  
Advanced Placement ◽  
Electron Transport Chain ◽  
Cellular Respiration ◽  
College Level ◽  
Inner Mitochondrial Membrane ◽  
College Biology ◽  
Everyday Objects ◽  
Transport Chain ◽  
Introductory College

This activity provides students an interactive demonstration of the electron transport chain and chemiosmosis during aerobic respiration. Students use simple, everyday objects as hydrogen ions and electrons and play the roles of the various proteins embedded in the inner mitochondrial membrane to show how this specific process in cellular respiration produces ATP. The activity works best as a supplement after you have already discussed the electron transport chain in lecture but can be used prior to instruction to help students visualize the processes that occur. This demonstration was designed for general college biology for majors at a community college, but it could be used in any introductory college-level or advanced placement biology course.

scholarly journals Age-Dependent Loss of Mitochondrial Function in Epithelial Tissue Can Be Reversed by Coenzyme Q10

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Daniel Schniertshauer ◽  
Daniel Gebhard ◽  
Jörg Bergemann
Keyword(s):  
Electron Transport ◽  
Coenzyme Q10 ◽  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Epithelial Tissue ◽  
Atp Production ◽  
Transport Chain ◽  
Respiratory Parameters ◽  
Age Dependent ◽  
Theory Of Aging

The process of aging is characterized by the increase of age-associated disorders as well as severe diseases. Due to their role in the oxidative phosphorylation and thus the production of ATP which is crucial for many cellular processes, one reason for this could be found in the mitochondria. The accumulation of reactive oxygen species damaged mitochondrial DNA and proteins can induce mitochondrial dysfunction within the electron transport chain. According to the “mitochondrial theory of aging,” understanding the impact of harmful external influences on mitochondrial function is therefore essential for a better view on aging in general, but the measurement of mitochondrial respiration in skin cells from cell cultures cannot completely reflect the real situation in skin. Here, we describe a new method to measure the mitochondrial respiratory parameters in epithelial tissue derived from human skin biopsies using a XF24 extracellular flux analyzer to evaluate the effect of coenzyme Q10. We observed a decrease in mitochondrial respiration and ATP production with donor age corresponding to the “mitochondrial theory of aging.” For the first time ex vivo in human epidermis, we could show also a regeneration of mitochondrial respiratory parameters if the reduced form of coenzyme Q10, ubiquinol, was administered. In conclusion, an age-related decrease in mitochondrial respiration and ATP production was confirmed. Likewise, an increase in the respiratory parameters by the addition of coenzyme Q10 could also be shown. The fact that there is a significant effect of administered coenzyme Q10 on the respiratory parameters leads to the assumption that this is mainly caused by an increase in the electron transport chain. This method offers the possibility of testing age-dependent effects of various substances and their influence on the mitochondrial respiration parameters in human epithelial tissue.

scholarly journals Heme Oxygenase-1 Supports Mitochondrial Energy Production and Electron Transport Chain Activity in Cultured Lung Epithelial Cells

2020 ◽  
Vol 21 (18) ◽  
pp. 6941
Author(s):  
Jennifer F. Carr ◽  
David Garcia ◽  
Alejandro Scaffa ◽  
Abigail L. Peterson ◽  
Andrew J. Ghio ◽  
...  
Keyword(s):  
Electron Transport ◽  
Heme Oxygenase ◽  
Electron Transport Chain ◽  
Iron Concentration ◽  
Heme Iron ◽  
Lung Epithelial Cells ◽  
Heme Oxygenase 1 ◽  
Protective Effects ◽  
Transport Chain

Heme oxygenase-1 is induced by many cellular stressors and catalyzes the breakdown of heme to generate carbon monoxide and bilirubin, which confer cytoprotection. The role of HO-1 likely extends beyond the simple production of antioxidants, for example HO-1 activity has also been implicated in metabolism, but this function remains unclear. Here we used an HO-1 knockout lung cell line to further define the contribution of HO-1 to cellular metabolism. We found that knockout cells exhibit reduced growth and mitochondrial respiration, measured by oxygen consumption rate. Specifically, we found that HO-1 contributed to electron transport chain activity and utilization of certain mitochondrial fuels. Loss of HO-1 had no effect on intracellular non-heme iron concentration or on proteins whose levels and activities depend on available iron. We show that HO-1 supports essential functions of mitochondria, which highlights the protective effects of HO-1 in diverse pathologies and tissue types. Our results suggest that regulation of heme may be an equally significant role of HO-1.

Method for recovering ATP content and mitochondrial function after chemical anoxia in renal cell cultures

1994 ◽  
Vol 266 (6) ◽  
pp. C1803-C1811 ◽  
Author(s):  
R. B. Doctor ◽  
R. Bacallao ◽  
L. J. Mandel
Keyword(s):  
Electron Transport ◽  
Oxidative Metabolism ◽  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Cultured Cells ◽  
Good Method ◽  
Complete Recovery ◽  
Specific Method ◽  
Cellular Effects ◽  
Transport Chain

Cultured renal cells provide a highly reproducible and malleable model to study cellular responses to metabolic perturbations. Nevertheless, there is currently no good method to achieve metabolic inhibition and complete recovery in cultured cells. This study describes a specific method for reversibly inhibiting both glycolytic and oxidative metabolism. Glycolysis was inhibited by removing all glycolytic substrates, and mitochondrial respiration was inhibited with rotenone, a site I inhibitor of the electron transport chain. Within 30 min, ATP values were decreased by 98%. Glycolysis was restored through the reintroduction of glucose. Oxidative metabolism was restored by the addition of heptanoate, a short odd-chain fatty acid, which supplies reducing equivalents to site II of the electron transport chain. Employing Madin-Darby canine kidney and LLC-PK1 cell lines, this protocol caused the immediate and complete recovery of mitochondrial respiration and, by 60 min, the complete recovery of cellular ATP levels. Application of this protocol should allow the investigation of the cellular effects and alterations that occur within cells recovering from sublethal energy depletion.

scholarly journals Tissue Factor Decryption By Oxidative Stress-Induced Lipid Peroxidation: Potential Mechanisms

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 125-125
Author(s):  
Shabbir Ansari ◽  
Usha R Pendurthi ◽  
L. Vijaya Mohan Rao
Keyword(s):  
Oxidative Stress ◽  
Electron Transport ◽  
P38 Mapk ◽  
Electron Transport Chain ◽  
Thioredoxin Reductase ◽  
Dependent Manner ◽  
Mapk Activation ◽  
Downstream Signaling ◽  
Transport Chain

Abstract Cellular lipid peroxidation is known to contribute to the initiation and propagation of atherothrombosis. Recently, we showed that 4-hydroxynonenal (HNE), one of the most abundant reactive aldehydes generated from the oxidation of ω-6 fatty acids, enhanced tissue factor (TF) activity on monocytic cells by externalizing phosphatidylserine (PS) in p38 MAPK activation-dependent manner. However, at present, the link between HNE-induced oxidative stress and p38 MAPK activation and the relation of p38 MAPK activation to PS externalization is not fully known. In the present study, we investigated the role of mitochondrial electron transport chain and reactive oxygen species (ROS) generation in HNE-mediated TF decryption. In addition, we also investigated the thioredoxin reductase-thioredoxin-ASK-1 axis in regulating p38 MAPK activation and PS externalization in decrypting TF. To elucidate potential mechanisms of HNE-induced TF decryption, we first determined the role of specific mitochondrial electron transport chain complexes in regulating TF activity. Since THP-1 cells used in the study had a measurable basal TF activity, they were not further treated with LPS or other agonists to induce TF synthesis. The electron transport chain in these cells was disrupted by specific inhibitors and cell surface TF activity was measured by factor X activation assay. Inhibition of complex I and complex IV by rotenone and sodium azide, respectively, enhanced the procoagulant activity of basal level TF. However, the inhibition of complex I and IV had no significant effect on the HNE-mediated increase in TF activity. Interestingly, inhibition of ATP synthase/complex V by oligomycin significantly inhibited the HNE-mediated enhanced TF activity, indicating that HNE-mediated TF decryption may involve the generation of ATP. In agreement with earlier published studies in monocytes/macrophages, stimulation of THP-1 cells with ATP increased cell surface TF activity. However, at present, it is yet to be shown that HNE treatment actually increased the production of ATP and that this ATP is responsible for the HNE-mediated TF decryption. It is also possible that HNE, either through a generation of ROS in mitochondria or directly, can affect the activity of thioredoxin either by intracellular signaling or by directly forming an adduct with it. Therefore, we next investigated the effect of HNE on the activity of thioredoxin reductase, the enzyme known to regulate thioredoxin activity in the cell. Our data showed that HNE treatment inhibited the activity of thioredoxin reductase in a concentration-dependent manner, 40 µM of HNE inhibiting 50% of the activity and a complete inhibition at 80µM of HNE. To further determine the downstream signaling cascade involved in the PS externalization and TF decryption on exposure to HNE, we analyzed the effect of HNE on the activation of MKK3 and MKK6, the protein kinases known to activate p38 MAPK and the downstream signaling activator of thioredoxin/thioredoxin reductase pathway. HNE treatment increased the phosphorylation of MKK3 and MKK6 in a time-dependent manner. In summary, our data suggest that HNE may mediate TF decryption via modulation of thioredoxin/thioredoxin reductase system, which results in activation of MKK3/MKK6, which in turn activates p38 MAPK that is responsible for PS externalization. The study highlights the potential role of oxidative stress in regulating TF activity in thrombotic disorders and provides a mechanistic link between disorders associated with cellular oxidative stress and thrombosis. Disclosures No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document