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Liu X, Chen L, Chen Z. Acid-triggered controlled release and fluorescence-switchable phthalocyanine nanoassemblies combined with O 2-economizer for tumor imaging and collaborative photodynamic antitumor therapy. Bioorg Chem 2024; 143:106986. [PMID: 37995641 DOI: 10.1016/j.bioorg.2023.106986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/09/2023] [Accepted: 11/18/2023] [Indexed: 11/25/2023]
Abstract
Photodynamic therapy (PDT) has emerged as a highly efficacious therapeutic modality for malignant tumors owing to its non-invasive property and minimal adverse effects. However, the pervasive hypoxic microenvironment within tumors significantly compromises the efficacy of oxygen-dependent PDT, posing a formidable challenge to the advancement of high-efficiency PDT. Here, we developed a nanostructured photosensitizer (PS) assembled by cationic and anionic zinc phthalocyanines to load oxygen-throttling drug atovaquone (ATO), which was subsequently coated with polydopamine to obtain the final product ATO/ZnPc-CA@DA. ATO/ZnPc-CA@DA exhibited excellent stability, particularly in the blood milieu. Interestingly, the acidic microenvironment can trigger drug release from ATO/ZnPc-CA@DA, leading to a significant enhancement in fluorescence and an augmented generation of reactive oxygen species (ROS). ATO/ZnPc-CA@DA can induce synergistic cytotoxicity of PS and ATO, and significantly enhance the killing ability against tumor cells under hypoxic conditions. The mechanism underlying cytotoxicity of ATO/ZnPc-CA@DA was demonstrated to be associated with augmented cell apoptosis, disruption of mitochondrial membrane potential, diminished ATP production, heightened intracellular ROS generation, and reduced intracellular oxygen consumption. The animal experiments indicated that ATO/ZnPc-CA@DA possessed enhanced tumor targeting capability, along with a reduction in PS distribution within normal organs. Furthermore, ATO/ZnPc-CA@DA exhibited enhanced inhibitory effect on tumor growth and caused aggravated damage to tumor tissue. The construction strategy of nanostructured PS and the synergistic antitumor principle of combined oxygen-throttling drugs can be applied to other PSs, thereby advancing the development of photodynamic antitumor therapy and promoting the clinical translation.
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Affiliation(s)
- Xinxin Liu
- Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao 266035, China.
| | - Lei Chen
- Tianjin Medical University, Tianjin 300070, China
| | - Ze Chen
- Tianjin Medical University, Tianjin 300070, China
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Wikström M, Pecorilla C, Sharma V. The mitochondrial respiratory chain. Enzymes 2023; 54:15-36. [PMID: 37945170 DOI: 10.1016/bs.enz.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
We present a brief review of the mitochondrial respiratory chain with emphasis on complexes I, III and IV, which contribute to the generation of protonmotive force across the inner mitochondrial membrane, and drive the synthesis of ATP by the process called oxidative phosphorylation. The basic structural and functional details of these complexes are discussed. In addition, we briefly review the information on the so-called supercomplexes, aggregates of complexes I-IV, and summarize basic physiological aspects of cell respiration.
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Affiliation(s)
- Mårten Wikström
- HiLife Institute of Biotechnology, University of Helsinki, Biocenter, Viikinkaari, Helsinki, Finland.
| | - Cristina Pecorilla
- Department of Physics, University of Helsinki, Gustaf Hällströmin katu, Helsinki, Finland
| | - Vivek Sharma
- HiLife Institute of Biotechnology, University of Helsinki, Biocenter, Viikinkaari, Helsinki, Finland; Department of Physics, University of Helsinki, Gustaf Hällströmin katu, Helsinki, Finland
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Wikström M, Gennis RB, Rich PR. Structures of the intermediates in the catalytic cycle of mitochondrial cytochrome c oxidase. Biochim Biophys Acta Bioenerg 2023; 1864:148933. [PMID: 36403794 DOI: 10.1016/j.bbabio.2022.148933] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/30/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022]
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Song F, Zhang G, Xu X, Polyak SW, Zhang K, Li H, Yang N. Role of intracellular energy metabolism in Mn(Ⅱ) removal by the novel bacterium Stenotrophomonas sp. MNB17. Chemosphere 2022; 308:136435. [PMID: 36113658 DOI: 10.1016/j.chemosphere.2022.136435] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/07/2022] [Accepted: 09/10/2022] [Indexed: 06/15/2023]
Abstract
Microorganism-mediated Mn(Ⅱ) removal has gained increasing attention as a valuble bioremediation approach. In this study, a novel strain Stenotrophomonas sp. MNB17 - obtained from marine sediments - was found to show Mn(Ⅱ) removal efficiencies of 98.51-99.38% within 7 days and 92.24% within 20 days at Mn(Ⅱ) concentrations of 10-40 mM and 50 mM, respectively. On day 7, 80.44% of 50 mM Mn(Ⅱ) was oxidized to Mn(Ⅲ/Ⅳ), whereas only 2.11-2.86% of 10-40 mM Mn(Ⅱ) was oxidized. This difference in the proportion of Mn-oxides suggested that the strain MNB17 could remove soluble Mn(Ⅱ) via distinct mechanisms under different Mn(Ⅱ) concentrations. At 10 mM Mn(Ⅱ), indirect mechanisms were employed by strain MNB17 to remove Mn(Ⅱ). The sufficient energy generated by increased cellular respiration led to enhanced ammonification, and MnCO3 was the main component of the Mn-precipitates (97.27%). Meanwhile, intracellular fatty acids were degraded and served as an important carbon source for respiration. At 50 mM Mn(Ⅱ), most of the soluble Mn(Ⅱ) was oxidized, and Mn-oxides dominated the Mn-precipitates (80.44%). Mn(Ⅱ) oxidation likely contributed to electrons for energy production, as the down-regulation of respiratory pathways resulted in a deficit of electron supply, which warrants futher study. The exogenous addition of tricarboxylic acid cycle substrates (malate, α-ketoglutarate, oxaloacetate, succinate, and fumarate) was found to accelerate Mn(Ⅱ) removal as MnCO3 at a concentration of 50 mM. Overall, this study reports a novel strain MNB17 with the biotechnological potential of Mn(Ⅱ) removal and elucidates the function of cellular energy metabolism during the Mn(Ⅱ) removal process. In addition, it demonstrates the potential of aerobic respiration-related substrates in accelerating the removal of high concentrations of Mn(Ⅱ) for the first time.
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Affiliation(s)
- Fuhang Song
- School of Light Industry, Beijing Technology and Business University, 11 Fucheng Road, Beijing, 100048, China
| | - Guoliang Zhang
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China
| | - Xiuli Xu
- School of Ocean Sciences, China University of Geosciences, 29 Xueyuan Road, Beijing, 100083, China
| | - Steven W Polyak
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, 5005, Australia
| | - Kai Zhang
- School of Light Industry, Beijing Technology and Business University, 11 Fucheng Road, Beijing, 100048, China
| | - Honghua Li
- School of Light Industry, Beijing Technology and Business University, 11 Fucheng Road, Beijing, 100048, China
| | - Na Yang
- CAS Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266237, China.
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Armand L, Fofana M, Couturier-Becavin K, Andriamihaja M, Blachier F. Dual effects of the tryptophan-derived bacterial metabolite indole on colonic epithelial cell metabolism and physiology: comparison with its co-metabolite indoxyl sulfate. Amino Acids 2022. [PMID: 35107624 DOI: 10.1007/s00726-021-03122-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 12/27/2021] [Indexed: 12/17/2022]
Abstract
Indole, which is produced by the intestinal microbiota from L-tryptophan, is recovered at millimolar concentrations in the human feces. Indoxyl sulfate (IS), the main indole co-metabolite, can be synthesized by the host tissues. Although indole has been shown to restore intestinal barrier function in experimental colitis, little is known on the effects of indole and IS on colonic epithelial cell metabolism and physiology. In this study, we compared the effects of indole and IS on the human colonic epithelial HT-29 Glc-/+ and Caco-2 cell lines, exposed to these compounds for 1-48 h. Indole, but not IS, was cytotoxic at 5 mM, altering markedly colonocyte proliferation. Both molecules, used up to 2.5 mM, induced a transient oxidative stress in colonocytes, that was detected after 1 h, but not after 48 h exposure. This was associated with the induction after 24 h of the expression of glutathione reductase, heme oxygenase, and cytochrome P450 (CYP)1B1. Indole and IS used at 2.5 mM impaired colonocyte respiration by diminishing mitochondrial oxygen consumption and maximal respiratory capacity. Indole, but not IS, displayed a slight genotoxic effect on colonocytes. Indole, but not IS, increased transepithelial resistance in colonocyte monolayers. Indole and IS used at 2.5 mM, induced a secretion of the pro-inflammatory interleukin-8 after 3 h incubation, and an increase of tumor necrosis factor-α secretion after 48 h. Although our results suggest beneficial effect of indole on epithelial integrity, overall they indicate that indole and IS share adverse effects on colonocyte respiration and production of reactive oxygen species, in association with the induction of enzymes of the antioxidant defense system. This latter process can be viewed as an adaptive response toward oxidative stress. Both compounds increased the production of inflammatory cytokines from colonocytes. However, only indole, but not IS, affected DNA integrity in colonocytes. Since colonocytes little convert indole to IS, the deleterious effects of indole on colonocytes appear to be unrelated to its conversion to IS.
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Spinelli S, Begani G, Guida L, Magnone M, Galante D, D'Arrigo C, Scotti C, Iamele L, De Jonge H, Zocchi E, Sturla L. LANCL1 binds abscisic acid and stimulates glucose transport and mitochondrial respiration in muscle cells via the AMPK/PGC-1α/Sirt1 pathway. Mol Metab 2021; 53:101263. [PMID: 34098144 PMCID: PMC8237609 DOI: 10.1016/j.molmet.2021.101263] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Abscisic acid (ABA) is a plant hormone also present and active in animals. In mammals, ABA regulates blood glucose levels by stimulating insulin-independent glucose uptake and metabolism in adipocytes and myocytes through its receptor LANCL2. The objective of this study was to investigate whether another member of the LANCL protein family, LANCL1, also behaves as an ABA receptor and, if so, which functional effects are mediated by LANCL1. METHODS ABA binding to human recombinant LANCL1 was explored by equilibrium-binding experiments with [3H]ABA, circular dichroism, and surface plasmon resonance. Rat L6 myoblasts overexpressing either LANCL1 or LANCL2, or silenced for the expression of both proteins, were used to investigate the basal and ABA-stimulated transport of a fluorescent glucose analog (NBDG) and the signaling pathway downstream of the LANCL proteins using Western blot and qPCR analysis. Finally, glucose tolerance and sensitivity to ABA were compared in LANCL2-/- and wild-type (WT) siblings. RESULTS Human recombinant LANCL1 binds ABA with a Kd between 1 and 10 μM, depending on the assay (i.e., in a concentration range that lies between the low and high-affinity ABA binding sites of LANCL2). In L6 myoblasts, LANCL1 and LANCL2 similarly, i) stimulate both basal and ABA-triggered NBDG uptake (4-fold), ii) activate the transcription and protein expression of the glucose transporters GLUT4 and GLUT1 (4-6-fold) and the signaling proteins AMPK/PGC-1α/Sirt1 (2-fold), iii) stimulate mitochondrial respiration (5-fold) and the expression of the skeletal muscle (SM) uncoupling proteins sarcolipin (3-fold) and UCP3 (12-fold). LANCL2-/- mice have a reduced glucose tolerance compared to WT. They spontaneously overexpress LANCL1 in the SM and respond to chronic ABA treatment (1 μg/kg body weight/day) with an improved glycemia response to glucose load and an increased SM transcription of GLUT4 and GLUT1 (20-fold) of the AMPK/PGC-1α/Sirt1 pathway and sarcolipin, UCP3, and NAMPT (4- to 6-fold). CONCLUSIONS LANCL1 behaves as an ABA receptor with a somewhat lower affinity for ABA than LANCL2 but with overlapping effector functions: stimulating glucose uptake and the expression of muscle glucose transporters and mitochondrial uncoupling and respiration via the AMPK/PGC-1α/Sirt1 pathway. Receptor redundancy may have been advantageous in animal evolution, given the role of the ABA/LANCL system in the insulin-independent stimulation of cell glucose uptake and energy metabolism.
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Affiliation(s)
- Sonia Spinelli
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy
| | - Giulia Begani
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy
| | - Lucrezia Guida
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy
| | - Mirko Magnone
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy
| | - Denise Galante
- Institute for Macromolecular Studies, National Research Council, Via De Marini 6, 16149, Genova, Italy
| | - Cristina D'Arrigo
- Institute for Macromolecular Studies, National Research Council, Via De Marini 6, 16149, Genova, Italy
| | - Claudia Scotti
- Department of Molecular Medicine, Immunology and General Pathology Unit, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy; Ardis Srl, Via Taramelli 24, 27100, Pavia, Italy
| | - Luisa Iamele
- Department of Molecular Medicine, Immunology and General Pathology Unit, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy; Ardis Srl, Via Taramelli 24, 27100, Pavia, Italy
| | - Hugo De Jonge
- Department of Molecular Medicine, Immunology and General Pathology Unit, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy; Ardis Srl, Via Taramelli 24, 27100, Pavia, Italy
| | - Elena Zocchi
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy.
| | - Laura Sturla
- Department of Experimental Medicine, Section of Biochemistry, School of Medical and Pharmaceutical Sciences, University of Genova, Viale Benedetto XV 1, 16132, Genova, Italy
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Zhang R, Chen B, Lin L, Zhang H, Luan T. 13C isotope-based metabolic flux analysis revealing cellular landscape of glucose metabolism in human liver cells exposed to perfluorooctanoic acid. Sci Total Environ 2021; 770:145329. [PMID: 33515891 DOI: 10.1016/j.scitotenv.2021.145329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/15/2021] [Accepted: 01/17/2021] [Indexed: 06/12/2023]
Abstract
Perfluorooctanoic acid (PFOA) is well known to break glucose homeostasis. However, the effects of PFOA on glucose metabolism are difficult to be evaluated because related metabolites may be synthesized from other nutritional substrates. Here, the relative contribution of glucose to metabolites (e.g., pyruvate and citrate) in the PFOA-treated human liver cells (HepG2) was determined using the 13C isotope-based metabolic flux analysis (MFA), i.e., pathway activities. The relative percentage of [U-13C6] glucose-derived pyruvate in cells exposed to PFOA was not significantly different from that in the controls, indicating that the metabolic pattern of glycolysis was not substantially changed by PFOA. The pathway activity of [U-13C6] glucose-driven tricarboxylic acid (TCA) cycle was dramatically inhibited by PFOA. Consequently, mitochondrial respiratory function was phenotypically impaired by PFOA, as observed from the decreasing basal oxygen consumption rate (OCR), ATP-linked OCR and spare respiratory capacity. This study suggests that PFOA may cause the abnormal glucose metabolism via altering the metabolic pattern of TCA cycle instead of glycolysis. The MFA is strongly recommended as a promising and robust tool to address the toxicity mechanisms of contaminants associated with glucose metabolism.
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Affiliation(s)
- Ruijia Zhang
- Sate Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Baowei Chen
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China.
| | - Li Lin
- Sate Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Hui Zhang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Tiangang Luan
- Sate Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China; Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
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Jougleux JL, Léger JL, Djeungoue-Petga MA, Roy P, Soucy MFN, Veilleux V, Hébert MPA, Hebert-Chatelain E, Boudreau LH. Evaluating the mitochondrial activity and inflammatory state of dimethyl sulfoxide differentiated PLB-985 cells. Mol Immunol 2021; 135:1-11. [PMID: 33838400 DOI: 10.1016/j.molimm.2021.03.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/14/2021] [Accepted: 03/31/2021] [Indexed: 12/19/2022]
Abstract
Neutrophils play a key role in the innate immunity with their ability to generate and release inflammatory mediators that promote the inflammatory response and consequently restore the hemostasis. As active participants in several steps of the normal inflammatory response, neutrophils are also involved in chronic inflammatory diseases such as asthma, atherosclerosis, and arthritis. Given their dual role in the modulation of inflammation, regulating the inflammatory response of neutrophils has been suggested as an important therapeutic approach by numerous researchers. The neutrophils have a relatively short lifespan, which can be problematic for some in vitro experiments. To address this issue, researchers have used the human monomyelocyte cell line PLB-985 as an in vitro model for exploratory experiments addressing neutrophil-related physiological functions. PLB-985 cells can be differentiated into a neutrophil-like phenotype upon exposure to several agonists, including dimethyl sulfoxide (DMSO). Whether this differentiation of PLB-985 affects important features related to the neutrophil's normal functions (i.e., mitochondrial activity, eicosanoid production) remains elusive, and characterizing these changes will be the focal point of this study. Our results indicate that the differentiation affected the proliferation of PLB-985 cells, without inducing apoptosis. A significant decrease in mitochondrial respiration was observed in differentiated PLB-985 cells. However, the overall mitochondria content was not affected. Immunoblotting with mitochondrial antibodies revealed a strong modulation of the succinate dehydrogenase A, superoxide dismutase 2, ubiquinol-cytochrome c reductase core protein 2 and ATP synthase subunit α in differentiated PLB-985 cells. Finally, eicosanoids (leukotriene B4, 12-hydroxyheptadecatrienoic and 15-hydroxyeicosatetraenoic acids) production was significantly increased in differentiated cells. In summary, our data demonstrate that the differentiation process of PLB-985 cells does not impact their viability despite a reduced respiratory state of the cells. This process is also accompanied by modulation of the inflammatory state of the cell. Of importance, our data suggest that PLB-985 cells could be suitable in vitro candidates to study mitochondrial-related dysfunctions in inflammatory diseases.
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Affiliation(s)
- Jean-Luc Jougleux
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Jacob L Léger
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Marie-Ange Djeungoue-Petga
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Department of Biology, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Patrick Roy
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Marie-France N Soucy
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Vanessa Veilleux
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Mathieu P A Hébert
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Etienne Hebert-Chatelain
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Department of Biology, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada
| | - Luc H Boudreau
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, Canada; New Brunswick Center for Precision Medicine, Moncton, NB, Canada.
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Pozdnyakov DI, Voronkov AV, Rukovitsyna VM. Chromon-3-aldehyde derivatives restore mitochondrial function in rat cerebral ischemia. Iran J Basic Med Sci 2020; 23:1172-1183. [PMID: 32963739 PMCID: PMC7491499 DOI: 10.22038/ijbms.2020.46369.10710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Objectives This work aimed to assess the effect of 10 new chromon-3-aldehyde derivatives on changes of mitochondrial function under the conditions of brain ischemia in rats. Materials and Methods The work was executed on BALB/c male-mice (acute toxicity was evaluated) and male Wistar rats, which were used to model cerebral ischemia by permanent middle cerebral artery occlusion. The test-substances, 10 derivatives of chromon-3-aldehyde and the reference drug, N-acetylcysteine, were injected after modeling of ischemia for 3 days. After that, neurological symptoms, the area of cerebral infarction, and change in mitochondrial function were evaluated. Results It was established that use of all chromon-3-aldehyde derivatives contributed to the recovery of mitochondrial function, which was reflected in enhanced ATP-generating activity, maximum respiration level, respiratory capacity, as well as reduction in the intensity of anaerobic reactions, apoptosis, and normalization of the mitochondrial membrane potential. The most pronounced changes were noted with the use of 6-acetyl substituted chromon-3-aldehyde derivative, the administration of which decreased neurological symptoms and size of brain necrosis area. Conclusion The obtained data may indicate the most pronounced neurotropic effect in a number of test-objects has the 6-acetyl substituted derivative of chromon-3 aldehyde, realized by restoration of mitochondrial function, which may be the basis for further study of chromon-3-aldehyde derivatives.
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Affiliation(s)
- Dmitry I Pozdnyakov
- Department of Pharmacology Pyatigorsk Medical Pharmaceutical Institute, Pyatigorsk, Russia
| | - Andrey V Voronkov
- Department of Pharmacology Pyatigorsk Medical Pharmaceutical Institute, Pyatigorsk, Russia
| | - Viktoriya M Rukovitsyna
- Department of Organic Chemistry, Pyatigorsk Medical Pharmaceutical Institute, Pyatigorsk, Russia
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10
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Haapanen O, Reidelbach M, Sharma V. Coupling of quinone dynamics to proton pumping in respiratory complex I. Biochim Biophys Acta Bioenerg 2020; 1861:148287. [PMID: 32777307 DOI: 10.1016/j.bbabio.2020.148287] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022]
Abstract
Respiratory complex I (NADH:quinone oxidoreductase) plays a central role in generating the proton electrochemical gradient in mitochondrial and bacterial membranes, which is needed to generate ATP. Several high-resolution structures of complex I have been determined, revealing its intricate architecture and complementing the biochemical and biophysical studies. However, the molecular mechanism of long-range coupling between ubiquinone (Q) reduction and proton pumping is not known. Computer simulations have been applied to decipher the dynamics of Q molecule in the ~30 Å long Q tunnel. In this short report, we discuss the binding and dynamics of Q at computationally predicted Q binding sites, many of which are supported by structural data on complex I. We suggest that the binding of Q at these sites is coupled to proton pumping by means of conformational rearrangements in the conserved loops of core subunits.
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Affiliation(s)
- Outi Haapanen
- Department of Physics, University of Helsinki, Finland
| | | | - Vivek Sharma
- Department of Physics, University of Helsinki, Finland; HiLIFE Institute of Biotechnology, University of Helsinki, Finland.
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Djurabekova A, Haapanen O, Sharma V. Proton motive function of the terminal antiporter-like subunit in respiratory complex I. Biochim Biophys Acta Bioenerg 2020; 1861:148185. [PMID: 32171794 DOI: 10.1016/j.bbabio.2020.148185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 01/15/2020] [Accepted: 03/09/2020] [Indexed: 12/20/2022]
Abstract
In the aerobic respiratory chains of many organisms, complex I functions as the first electron input. By reducing ubiquinone (Q) to ubiquinol, it catalyzes the translocation of protons across the membrane as far as ~200 Å from the site of redox reactions. Despite significant amount of structural and biochemical data, the details of redox coupled proton pumping in complex I are poorly understood. In particular, the proton transfer pathways are extremely difficult to characterize with the current structural and biochemical techniques. Here, we applied multiscale computational approaches to identify the proton transfer paths in the terminal antiporter-like subunit of complex I. Data from combined classical and quantum chemical simulations reveal for the first time structural elements that are exclusive to the subunit, and enables the enzyme to achieve coupling between the spatially separated Q redox reactions and proton pumping. By studying long time scale protonation and hydration dependent conformational dynamics of key amino acid residues, we provide novel insights into the proton pumping mechanism of complex I.
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Affiliation(s)
| | - Outi Haapanen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
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12
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Malkamäki A, Meunier B, Reidelbach M, Rich PR, Sharma V. The H channel is not a proton transfer path in yeast cytochrome c oxidase. Biochim Biophys Acta Bioenerg 2019; 1860:717-723. [PMID: 31374214 DOI: 10.1016/j.bbabio.2019.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/24/2019] [Accepted: 07/29/2019] [Indexed: 10/26/2022]
Abstract
Cytochrome c oxidases (CcOs) in the respiratory chains of mitochondria and bacteria are primary consumers of molecular oxygen, converting it to water with the concomitant pumping of protons across the membrane to establish a proton electrochemical gradient. Despite a relatively well understood proton pumping mechanism of bacterial CcOs, the role of the H channel in mitochondrial forms of CcO remains debated. Here, we used site-directed mutagenesis to modify a central residue of the lower span of the H channel, Q413, in the genetically tractable yeast Saccharomyces cerevisiae. Exchange of Q413 to several different amino acids showed no effect on rates and efficiencies of respiratory cell growth, and redox potential measurements indicated minimal electrostatic interaction between the 413 locus and the nearest redox active component heme a. These findings clearly exclude a primary role of this section of the H channel in proton pumping in yeast CcO. In agreement with the experimental data, atomistic molecular dynamics simulations and continuum electrostatic calculations on wildtype and mutant yeast CcOs highlight potential bottlenecks in proton transfer through this route. Our data highlight the preference for neutral residues in the 413 locus, precluding sufficient hydration for formation of a proton conducting wire.
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Affiliation(s)
- Aapo Malkamäki
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland
| | - Brigitte Meunier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris Saclay, 91198 Gif sur Yvette, France
| | - Marco Reidelbach
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland
| | - Peter R Rich
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Vivek Sharma
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland; Institute of Biotechnology, P. O. Box 56, University of Helsinki, 00014 Helsinki, Finland.
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Galemou Yoga E, Haapanen O, Wittig I, Siegmund K, Sharma V, Zickermann V. Mutations in a conserved loop in the PSST subunit of respiratory complex I affect ubiquinone binding and dynamics. Biochim Biophys Acta Bioenerg 2019; 1860:573-81. [PMID: 31226318 DOI: 10.1016/j.bbabio.2019.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/10/2019] [Accepted: 06/15/2019] [Indexed: 12/13/2022]
Abstract
Respiratory complex I catalyses the reduction of ubiquinone (Q) from NADH coupled to proton pumping across the inner membrane of mitochondria. The electrical charging of the inner mitochondrial membrane drives the synthesis of ATP, which is used to power biochemical reactions of the cell. The recent surge in structural data on complex I from bacteria and mitochondria have contributed to significant understanding of its molecular architecture. However, despite these accomplishments, the role of various subdomains in redox-coupled proton pumping remains entirely unclear. In this work, we have mutated conserved residues in the loop of the PSST subunit that faces the ~30 Å long unique Q-binding tunnel of respiratory complex I. The data show a drastic decrease in Q reductase activity upon mutating several residues despite full assembly of the complex. In-silico modeling and multiple microsecond long molecular dynamics simulations of wild-type and enzyme variants with exchanges of conserved arginine residues revealed remarkable ejection of the bound Q from the site near terminal electron donor N2. Based on experiments and long-time scale molecular simulations, we identify microscopic elements that dynamically control the diffusion of Q and are central to redox-coupled proton pumping in respiratory complex I.
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Armand L, Andriamihaja M, Gellenoncourt S, Bitane V, Lan A, Blachier F. In vitro impact of amino acid-derived bacterial metabolites on colonocyte mitochondrial activity, oxidative stress response and DNA integrity. Biochim Biophys Acta Gen Subj 2019; 1863:1292-301. [PMID: 31034912 DOI: 10.1016/j.bbagen.2019.04.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 04/11/2019] [Accepted: 04/25/2019] [Indexed: 01/13/2023]
Abstract
BACKGROUND 4-hydroxyphenylacetic acid (HO-PAA) is produced by intestinal microbiota from L-tyrosine. High concentrations in human fecal water have been associated with cytotoxicity, urging us to test HO-PAA's effects on human colonocytes. We compared these effects with those of phenylacetic acid (PAA), phenol and acetaldehyde, also issued from amino acids fermentation. METHODS HT-29 Glc-/+ human colonocytes were exposed for 24 h to metabolites at concentrations between 350 and 1000 μM for HO-PAA and PAA, 250-1500 μM for phenol and 25-500 μM for acetaldehyde. We evaluated metabolites'cytotoxicity with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide and DNA quantification assays, reactive oxygen species (ROS) production with H2DCF-DA, and DNA damage with the comet assay. We measured cell oxygen consumption and mitochondrial complexes activity by polarography. RESULTS Although HO-PAA displayed no cytotoxic effect on colonocytes, it decreased mitochondrial complex I activity and oxygen consumption. This was paralleled by an increase in ROS production and DNA alteration. Cells pretreatment with N-acetylcysteine, a ROS scavenger, decreased genotoxic effects of HO-PAA, indicating implication of oxidative stress in HO-PAA's genotoxicity. PAA and phenol did not reproduce these effects, but were cytotoxic towards colonocytes. Last, acetaldehyde displayed no effect in terms of cytotoxicity and mitochondrial metabolic activity, but increased DNA damage. CONCLUSIONS Several bacterial metabolites produced from amino acids displayed deleterious effects on human colonocytes, in terms of genotoxicity (HO-PAA and acetaldehyde) or cytotoxicity (PAA and phenol). GENERAL SIGNIFICANCE This study helps understanding the consequences of intestinal microbiota's metabolic activity on the host since amino acids fermentation can lead to the formation of compounds toxic towards colonic epithelial cells.
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Cai T, Hua B, Luo D, Xu L, Cheng Q, Yuan G, Yan Z, Sun N, Hua L, Lu C. The circadian protein CLOCK regulates cell metabolism via the mitochondrial carrier SLC25A10. Biochim Biophys Acta Mol Cell Res 2019; 1866:1310-1321. [PMID: 30943427 DOI: 10.1016/j.bbamcr.2019.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/11/2019] [Accepted: 03/29/2019] [Indexed: 12/17/2022]
Abstract
Physiological function and metabolic regulation are the most important outputs of circadian clock controls in mammals. Mitochondrial respiration and ROS production show rhythmic activity. Mitochondrial carriers, which are responsible for mitochondrial substance transfer, are vital for mitochondrial metabolism. Clock (Circadian Locomotor Output Cycles Kaput) is the first core circadian gene identified in mammalian animals. However, whether CLOCK protein can regulate mitochondrial functions via mitochondrial carriers is unclear. Here, we showed that CLOCK can bind to the mitochondrial carrier SLC25A10. For further analysis, we established a Slc25a10-/--Hepa1-6 cell line using CRISPR/Cas9 gene-editing technology. Slc25a10-/--Hepa1-6 cells showed disordered glucose homeostasis, increased oxidative stress levels, and damaged electron transport chains. Next, using an immunoprecipitation assay, we found that amino acids 43-84 and 169-210 in SLC25A10 are key sites that respond to CLOCK binding. Finally, forced expression of wild-type SLC25A10 in Slc25a10-/--Hepa1-6 cells could compensate for the loss of SLC25A10; the decreased glucose metabolism, severe oxidative stress and damaged electron transport chain were recovered. In addition, a mutant Slc25a10 with changes in two key sites did not show a rescue effect. In conclusion, we identified a new protein-protein interaction mechanism in which CLOCK can directly regulate cell metabolism via the mitochondrial membrane transporter SLC25A10. Our study might provide some new insights into the relationship between circadian clock and mitochondrial metabolism.
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Affiliation(s)
- Tingting Cai
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Bingxuan Hua
- Department of Orthopedics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Dawei Luo
- Department of Ophthalmology, Shanghai First People's Hospital affiliated with Shanghai Jiaotong University, Shanghai, China
| | - Lirong Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Qianyun Cheng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Gongsheng Yuan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Zuoqin Yan
- Department of Orthopedics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ning Sun
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Luchun Hua
- Department of Surgery, Huashan Hospital, Fudan University, Shanghai, China.
| | - Chao Lu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China; Research Center on Aging and Medicine, Fudan University, Shanghai, China; Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.
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Gerencser AA. Metabolic activation-driven mitochondrial hyperpolarization predicts insulin secretion in human pancreatic beta-cells. Biochim Biophys Acta Bioenerg 2018; 1859:817-828. [PMID: 29886047 DOI: 10.1016/j.bbabio.2018.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/18/2018] [Accepted: 06/05/2018] [Indexed: 12/31/2022]
Abstract
Mitochondrial metabolism plays a central role in insulin secretion in pancreatic beta-cells. Generation of protonmotive force and ATP synthesis from glucose-originated pyruvate are critical steps in the canonical pathway of glucose-stimulated insulin secretion. Mitochondrial metabolism is intertwined with pathways that are thought to amplify insulin secretion with mechanisms distinct from the canonical pathway, and the relative importance of these two pathways is controversial. Here I show that glucose-induced mitochondrial membrane potential (MMP) hyperpolarization is necessary for, and predicts, the rate of insulin secretion in primary cultured human beta-cells. When glucose concentration is elevated, increased metabolism results in a substantial MMP hyperpolarization, as well as in increased rates of ATP synthesis and turnover marked by faster cell respiration. Using modular kinetic analysis I explored what properties of cellular energy metabolism enable a large glucose-induced change in MMP in human beta-cells. I found that an ATP-dependent pathway activates glucose or substrate oxidation, acting as a positive feedback in energy metabolism. This activation mechanism is essential for concomitant fast respiration and high MMP, and for a high magnitude glucose-induced MMP hyperpolarization and therefore for insulin secretion.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Image Analyst Software, 43 Nova Lane, Novato, CA 94945, United States.
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Uber A, Grossestreuer AV, Ross CE, Patel PV, Trehan A, Donnino MW, Berg KM. Preliminary observations in systemic oxygen consumption during targeted temperature management after cardiac arrest. Resuscitation 2018; 127:89-94. [PMID: 29626611 DOI: 10.1016/j.resuscitation.2018.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/13/2018] [Accepted: 04/02/2018] [Indexed: 12/27/2022]
Abstract
AIM Limited data suggests low oxygen consumption (VO2), driven by mitochondrial injury, is associated with mortality after cardiac arrest. Due to the challenges of measurement in the critically ill, post-arrest metabolism remains poorly characterized. We monitored VO2, carbon dioxide production (VCO2) and the respiratory quotient (RQ) in post-arrest patients and explored associations with outcome. METHODS Using a gas exchange monitor, we measured continuous VO2 and VCO2 in post- arrest patients treated with targeted temperature management. We used area under the curve and medians over time to evaluate the association between VO2, VCO2, RQ and the VO2:lactate ratio with survival. RESULTS In 17 patients, VO2 in the first 12 h after return of spontaneous circulation (ROSC) was associated with survival (median in survivors 3.35 mL/kg/min [2.98,3.88] vs. non-survivors 2.61 mL/kg/min [2.21,2.94], p = .039). This did not persist over 24 h. The VO2:lactate ratio was associated with survival (median in survivors 1.4 [IQR: 1.1,1.7] vs. non-survivors 0.8 [IQR: 0.6,1.2] p < 0.001). Median RQ was 0.66 (IQR 0.63,0.70) and 71% of RQ measurements were <0.7. Patients with initial RQ < 0.7 had 17% survival versus 64% with initial RQ > 0.7 (p = .131). VCO2 was not associated with survival. CONCLUSIONS There was a significant association between VO2 and mortality in the first 12 h after ROSC, but not over 24 h. Lower VO2: lactate ratio was associated with mortality. A large percentage of patients had RQs below physiologic norms. Further research is needed to explore whether these parameters could have true prognostic value or be a potential treatment target.
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Hummer G, Wikström M. Molecular simulation and modeling of complex I. Biochim Biophys Acta 2016; 1857:915-21. [PMID: 26780586 DOI: 10.1016/j.bbabio.2016.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 11/23/2022]
Abstract
Molecular modeling and molecular dynamics simulations play an important role in the functional characterization of complex I. With its large size and complicated function, linking quinone reduction to proton pumping across a membrane, complex I poses unique modeling challenges. Nonetheless, simulations have already helped in the identification of possible proton transfer pathways. Simulations have also shed light on the coupling between electron and proton transfer, thus pointing the way in the search for the mechanistic principles underlying the proton pump. In addition to reviewing what has already been achieved in complex I modeling, we aim here to identify pressing issues and to provide guidance for future research to harness the power of modeling in the functional characterization of complex I. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
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Kondrashina AV, Ogurtsov VI, Papkovsky DB. Comparison of the three optical platforms for measurement of cellular respiration. Anal Biochem 2014; 468:1-3. [PMID: 25233002 DOI: 10.1016/j.ab.2014.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/29/2014] [Accepted: 09/04/2014] [Indexed: 11/29/2022]
Abstract
We compared three optical platforms for measurement of cellular respiration: absolute oxygen consumption rates (OCRs) in hermetically sealed microcuvettes, relative OCRs measured in a 96-well plate with oil seal, and steady-state oxygenation of cells in an open 96-well plate. Using mouse embryonic fibroblasts cell line, the phosphorescent intracellular O2 probe MitoXpress-Intra, and time-resolved fluorescence reader, we determined algorithms for conversion of relative OCRs and cell oxygenation into absolute OCRs, thereby allowing simple high-throughput measurement of absolute OCR values.
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Affiliation(s)
- Alina V Kondrashina
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | | | - Dmitri B Papkovsky
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
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Ryan TE, Erickson ML, Young HJ, McCully KK. Case report: endurance electrical stimulation training improves skeletal muscle oxidative capacity in chronic spinal cord injury. Arch Phys Med Rehabil 2013; 94:2559-2561. [PMID: 23816924 DOI: 10.1016/j.apmr.2013.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To describe the use of a novel neuromuscular electrical stimulation (NMES) endurance exercise protocol and its effects on skeletal muscle oxidative capacity. DESIGN Case report, pre/post intervention. SETTING University-based trial. PARTICIPANT A 39-year-old man who suffered a motor complete spinal cord injury (C5-6, ASIA Impairment Scale grade A). INTERVENTION Twenty-four weeks of endurance NMES that consisted of progressive increases in the twitch frequency, duration of sessions, and sessions per week. MAIN OUTCOME MEASURE Mitochondrial capacity was measured, in vivo, as the rate of recovery of muscle oxygen consumption using near-infrared spectroscopy. RESULTS The rate of recovery of muscle oxygen consumption increased approximately 3-fold from 0.52 to 1.43, 1.46, and 1.40/min measured on 3 separate occasions during week 12 of training, and 1.57/min after 24 weeks of NMES endurance training. CONCLUSION The findings of this study suggest that NMES endurance training using twitches can increase mitochondrial capacity to comparable levels measured in nonparalyzed muscles of sedentary able-bodied controls.
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Affiliation(s)
- Terence E Ryan
- Department of Kinesiology, University of Georgia, Athens, GA.
| | | | - Hui-Ju Young
- Department of Kinesiology, University of Georgia, Athens, GA
| | - Kevin K McCully
- Department of Kinesiology, University of Georgia, Athens, GA
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Ryan TE, Brizendine JT, Backus D, McCully KK. Electrically induced resistance training in individuals with motor complete spinal cord injury. Arch Phys Med Rehabil 2013; 94:2166-73. [PMID: 23816921 DOI: 10.1016/j.apmr.2013.06.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/12/2013] [Accepted: 06/12/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To examine the effects of 16 weeks of electrically induced resistance training on insulin resistance and glucose tolerance, and changes in muscle size, composition, and metabolism in paralyzed muscle. DESIGN Pre-post intervention. SETTING University-based trial. PARTICIPANTS Participants (N=14; 11 men and 3 women) with chronic (>2y post spinal cord injury), motor complete spinal cord injury. INTERVENTION Home-based electrically induced resistance exercise training twice weekly for 16 weeks. MAIN OUTCOME MEASURES Plasma glucose and insulin throughout a standard clinical oral glucose tolerance test, thigh muscle and fat mass via dual-energy x-ray absorptiometry, quadriceps and hamstrings muscle size and composition via magnetic resonance imaging, and muscle oxidative metabolism using phosphorus magnetic resonance spectroscopy. RESULTS Muscle mass increased in all participants (mean ± SD, 39%±27%; range, 5%-84%). The mean change ± SD in intramuscular fat was 3%±22%. Phosphocreatine mean recovery time constants ± SD were 102±24 and 77±18 seconds before and after electrical stimulation-induced resistance training, respectively (P<.05). There was no improvement in fasting blood glucose levels, homeostatic model assessment calculated insulin resistance, 2-hour insulin, or 2-hour glucose. CONCLUSIONS Sixteen weeks of electrical stimulation-induced resistance training increased muscle mass, but did not reduce intramuscular fat. Similarly, factors associated with insulin resistance or glucose tolerance did not improve with training. We did find a 25% improvement in mitochondrial function, as measured by phosphocreatine recovery rates. Larger improvements in mitochondrial function may translate into improved glucose tolerance and insulin resistance.
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Affiliation(s)
- Terence E Ryan
- Department of Kinesiology, University of Georgia, Athens, GA.
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