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Frousiakis SE, Pouw AE, Karanjia R, Sadun AA. A Female Patient with Down Syndrome and Low-Penetrance Leber's Hereditary Optic Neuropathy. Case Rep Ophthalmol 2014; 5:405-10. [PMID: 25566062 PMCID: PMC4280465 DOI: 10.1159/000369612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We present the case of a 19-year-old female with a history of Down syndrome (DS) who was referred to our neuro-ophthalmology clinic for evaluation of Leber's hereditary optic neuropathy (LHON). The patient's family history was significant for a known G11778A mutation in a maternal relative, consistent with LHON. The patient was also positive for the G11778A mutation; however, the genotype demonstrated low penetrance in the pedigree, with only 1 out of 10 adult male offspring showing signs or symptoms of the disease. Mitochondrial mutations implicated in LHON have been shown to impair complex I of the electron transport chain and thereby reducing the effective generation of adenosine triphosphate and increasing the production of toxic reactive oxygen species. Although the partial or complete triplicate of chromosome 21 constitutes the etiology of DS, some of the pleiotropic phenotypes of the syndrome have been attributed to oxidative stress and mitochondrial dysfunction. Given the low penetrance of the mutation and the patient's sex, this case illustrates the possibility that the mitochondrial mutation demonstrated increased penetrance due to pre-existing mitochondrial dysfunction related to DS.
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Affiliation(s)
- Starleen E. Frousiakis
- Keck School of Medicine, University of Southern California, Calif., USA
- *Starleen E. Frousiakis, Keck School of Medicine, University of Southern California, 1975 Zonal Avenue, Los Angeles, CA 90098 (USA), E-Mail
| | - Andrew E. Pouw
- Keck School of Medicine, University of Southern California, Calif., USA
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102
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Jennings P, Schwarz M, Landesmann B, Maggioni S, Goumenou M, Bower D, Leonard MO, Wiseman JS. SEURAT-1 liver gold reference compounds: a mechanism-based review. Arch Toxicol 2014; 88:2099-133. [DOI: 10.1007/s00204-014-1410-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 10/01/2014] [Indexed: 12/20/2022]
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103
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Jeong MH, Kim JH, Seo KS, Kwak TH, Park WJ. β-Lapachone attenuates mitochondrial dysfunction in MELAS cybrid cells. Biochem Biophys Res Commun 2014; 454:417-22. [PMID: 25451262 DOI: 10.1016/j.bbrc.2014.10.093] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 10/19/2014] [Indexed: 02/05/2023]
Abstract
Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease caused by mutations in the mitochondrial genome. This study investigated the efficacy of β-lapachone (β-lap), a natural quinone compound, in rescuing mitochondrial dysfunction in MELAS cybrid cells. β-Lap significantly restored energy production and mitochondrial membrane potential as well as normalized the elevated ROS level in MELAS cybrid cells. Additionally, β-lap reduced lactic acidosis and restored glucose uptake in the MELAS cybrid cells. Finally, β-lap activated Sirt1 by increasing the intracellular NAD(+)/NADH ratio, which was accompanied by increased mtDNA content. Two other quinone compounds (idebenone and CoQ10) that have rescued mitochondrial dysfunction in previous studies of MELAS cybrid cells had a minimal effect in the current study. Taken together, these results demonstrated that β-lap may provide a novel therapeutic modality for the treatment of MELAS.
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Affiliation(s)
- Moon Hee Jeong
- College of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Jin Hwan Kim
- R&D Center, KT&G Life Sciences Corp., Suwon, Republic of Korea
| | - Kang-Sik Seo
- R&D Center, KT&G Life Sciences Corp., Suwon, Republic of Korea
| | - Tae Hwan Kwak
- R&D Center, KT&G Life Sciences Corp., Suwon, Republic of Korea
| | - Woo Jin Park
- College of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
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104
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Jaber S, Polster BM. Idebenone and neuroprotection: antioxidant, pro-oxidant, or electron carrier? J Bioenerg Biomembr 2014; 47:111-8. [PMID: 25262284 DOI: 10.1007/s10863-014-9571-y] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/15/2014] [Indexed: 12/30/2022]
Abstract
UNLABELLED Ubiquinone, commonly called coenzyme Q10 (CoQ), is a lipophilic electron carrier and endogenous antioxidant found in all cellular membranes. In the mitochondrial inner membrane it transfers electrons to complex III of the electron transport chain. The short chain CoQ analogue idebenone is in clinical trials for a number of diseases that exhibit a mitochondrial etiology. Nevertheless, evidence that idebenone ameliorates neurological symptoms in human disease is inconsistent. Although championed as an antioxidant, idebenone can also act as a pro-oxidant by forming an unstable semiquinone at complex I. The antioxidant function of idebenone is critically dependent on two-electron reduction to idebenol without the creation of unstable intermediates. Recently, cytoplasmic NAD(P)H quinone oxidoreductase 1 (NQO1) was identified as a major enzyme catalyzing idebenone reduction. While reduction allows idebenone to act as an antioxidant, evidence also suggests that NQO1 enables idebenone to shuttle reducing equivalents from cytoplasmic NAD(P)H to mitochondrial complex III, bypassing any upstream damage to the electron transport chain. In this mini-review we discuss how idebenone can influence mitochondrial function within the context of cytoprotection. Importantly, in the brain NQO1 is expressed primarily by glia rather than neurons. As NQO1 is an inducible enzyme regulated by oxidative stress and the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway, optimizing NQO1 expression in appropriate cell types within a specific disease context may be key to delivering on idebenone's therapeutic potential.
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Affiliation(s)
- Sausan Jaber
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore St., MSTF 5-34, Baltimore, MD, 21201, USA
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105
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Ogawa S, Takemura H, Horiguchi H, Terao M, Haji T, Pestilli F, Yeatman JD, Tsuneoka H, Wandell BA, Masuda Y. White matter consequences of retinal receptor and ganglion cell damage. Invest Ophthalmol Vis Sci 2014; 55:6976-86. [PMID: 25257055 DOI: 10.1167/iovs.14-14737] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Patients with Leber hereditary optic neuropathy (LHON) and cone-rod dystrophy (CRD) have central vision loss; but CRD damages the retinal photoreceptor layer, and LHON damages the retinal ganglion cell (RGC) layer. Using diffusion MRI, we measured how these two types of retinal damage affect the optic tract (ganglion cell axons) and optic radiation (geniculo-striate axons). METHODS Adult onset CRD (n = 5), LHON (n = 6), and healthy controls (n = 14) participated in the study. We used probabilistic fiber tractography to identify the optic tract and the optic radiation. We compared axial and radial diffusivity at many positions along the optic tract and the optic radiation. RESULTS In both types of patients, diffusion measures within the optic tract and the optic radiation differ from controls. The optic tract change is principally a decrease in axial diffusivity; the optic radiation change is principally an increase in radial diffusivity. CONCLUSIONS Both photoreceptor layer (CRD) and retinal ganglion cell (LHON) retinal disease causes substantial change in the visual white matter. These changes can be measured using diffusion MRI. The diffusion changes measured in the optic tract and the optic radiation differ, suggesting that they are caused by different biological mechanisms.
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Affiliation(s)
- Shumpei Ogawa
- Department of Psychology, Stanford University, Stanford, California, United States Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiromasa Takemura
- Department of Psychology, Stanford University, Stanford, California, United States Department of Psychology, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Horiguchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Masahiko Terao
- Department of Psychology, The University of Tokyo, Tokyo, Japan Tamagawa University Brain Science Institute, Machida, Japan
| | - Tomoki Haji
- Department of Ophthalmology, Atsugi City Hospital, Kanagawa, Japan
| | - Franco Pestilli
- Department of Psychology, Stanford University, Stanford, California, United States
| | - Jason D Yeatman
- Department of Psychology, Stanford University, Stanford, California, United States
| | - Hiroshi Tsuneoka
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Brian A Wandell
- Department of Psychology, Stanford University, Stanford, California, United States
| | - Yoichiro Masuda
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan The Japan Society for the Promotion of Science, Tokyo, Japan
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106
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Kim HJ, Oh GS, Shen A, Lee SB, Choe SK, Kwon KB, Lee S, Seo KS, Kwak TH, Park R, So HS. Augmentation of NAD(+) by NQO1 attenuates cisplatin-mediated hearing impairment. Cell Death Dis 2014; 5:e1292. [PMID: 24922076 PMCID: PMC4611728 DOI: 10.1038/cddis.2014.255] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/18/2014] [Accepted: 05/09/2014] [Indexed: 12/20/2022]
Abstract
Cisplatin (cis-diaminedichloroplatinum-II) is an extensively used chemotherapeutic agent, and one of its most adverse effects is ototoxicity. A number of studies have demonstrated that these effects are related to oxidative stress and DNA damage. However, the precise mechanism underlying cisplatin-associated ototoxicity is still unclear. The cofactor nicotinamide adenine dinucleotide (NAD(+)) has emerged as a key regulator of cellular energy metabolism and homeostasis. Here, we demonstrate for the first time that, in cisplatin-mediated ototoxicity, the levels and activities of SIRT1 are suppressed by the reduction of intracellular NAD(+) levels. We provide evidence that the decrease in SIRT1 activity and expression facilitated by increasing poly(ADP-ribose) transferase (PARP)-1 activation and microRNA-34a through p53 activation aggravates cisplatin-mediated ototoxicity. Moreover, we show that the induction of cellular NAD(+) levels using β-lapachone (β-Lap), whose intracellular target is NQO1, prevents the toxic effects of cisplatin through the regulation of PARP-1 and SIRT1 activity. These results suggest that direct modulation of cellular NAD(+) levels by pharmacological agents could be a promising therapeutic approach for protection from cisplatin-induced ototoxicity.
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Affiliation(s)
- H-J Kim
- Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea
| | - G-S Oh
- Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea
| | - A Shen
- 1] Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea [2] BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University Graduate School, Jeonbuk, Republic of Korea
| | - S-B Lee
- 1] Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea [2] BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University Graduate School, Jeonbuk, Republic of Korea
| | - S-K Choe
- Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea
| | - K-B Kwon
- 1] Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea [2] BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University Graduate School, Jeonbuk, Republic of Korea [3] Department of Oriental Medical Physiology, College of Korean Medicine, Wonkwang University, Jeonbuk, Republic of Korea
| | - S Lee
- Life Science Research Center, KT&G Life Sciences, Suwon, Republic of Korea
| | - K-S Seo
- Life Science Research Center, KT&G Life Sciences, Suwon, Republic of Korea
| | - T H Kwak
- Life Science Research Center, KT&G Life Sciences, Suwon, Republic of Korea
| | - R Park
- 1] Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea [2] BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University Graduate School, Jeonbuk, Republic of Korea
| | - H-S So
- 1] Center for Metabolic Function Regulation, Department of Microbiology, Wonkwang University School of Medicine, Jeonbuk, Republic of Korea [2] BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University Graduate School, Jeonbuk, Republic of Korea
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107
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Leonardi A, Crasci’ L, Panico A, Pignatello R. Antioxidant activity of idebenone-loaded neutral and cationic solid–lipid nanoparticles. Pharm Dev Technol 2014; 20:716-23. [DOI: 10.3109/10837450.2014.915572] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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108
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Coenzyme Q10 as a therapy for mitochondrial disease. Int J Biochem Cell Biol 2014; 49:105-11. [PMID: 24495877 DOI: 10.1016/j.biocel.2014.01.020] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/14/2014] [Accepted: 01/26/2014] [Indexed: 01/11/2023]
Abstract
Treatment of mitochondrial respiratory chain (MRC) disorders is extremely difficult, however, coenzyme Q10 (CoQ10) and its synthetic analogues are the only agents which have shown some therapeutic benefit to patients. CoQ10 serves as an electron carrier in the MRC as well as functioning as a potent lipid soluble antioxidant. CoQ10 supplementation is fundamental to the treatment of patients with primary defects in the CoQ10 biosynthetic pathway. The efficacy of CoQ10 and its analogues in the treatment of patients with MRC disorders not associated with a CoQ10 deficiency indicates their ability to restore electron flow in the MRC and/or increase mitochondrial antioxidant capacity may also be important contributory factors to their therapeutic potential.
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109
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Neuroprotective effects of idebenone against pilocarpine-induced seizures: modulation of antioxidant status, DNA damage and Na(+), K (+)-ATPase activity in rat hippocampus. Neurochem Res 2014; 39:394-402. [PMID: 24414170 DOI: 10.1007/s11064-014-1236-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 12/18/2022]
Abstract
The current study investigated the neuroprotective activity of idebenone against pilocarpine-induced seizures and hippocampal injury in rats. Idebenone is a ubiquinone analog with antioxidant, and ATP replenishment effects. It is well tolerated and has low toxicity. Previous studies reported the protective effects of idebenone against neurodegenerative diseases such as Friedreich's ataxia and Alzheimer's disease. So far, the efficacy of idebenone in experimental models of seizures has not been tested. To achieve this aim, rats were randomly distributed into six groups. Two groups were treated with either normal saline (0.9 %, i.p., control group) or idebenone (200 mg/kg, i.p., Ideb200 group) for three successive days. Rats of the other four groups (P400, Ideb50 + P400, Ideb100 + P400, and Ideb200 + P400) received either saline or idebenone (50, 100, 200 mg/kg, i.p.) for 3 days, respectively followed by a single dose of pilocarpine (400 mg/kg, i.p.). All rats were observed for 6 h post pilocarpine injection. Latency to the first seizure, and percentages of seizures and survival were recorded. Surviving animals were sacrificed, and the hippocampal tissues were separated and used for the measurement of lipid peroxides, total nitrate/nitrite, glutathione and DNA fragmentation levels, in addition to catalase and Na(+), K(+)-ATPase activities. Results revealed that in a dose-dependent manner, idebenone (100, 200 mg/kg) prolonged the latency to the first seizure, elevated the percentage of survival and diminished the percentage of pilocapine-induced seizures in rats. Significant increases in lipid peroxides, total nitrate/nitrite, DNA fragmentation levels and catalase activity, in addition to a significant reduction in glutathione level and Na(+), K(+)-ATPase activity were observed in pilocarpine group. Pre-administration of idebenone (100, 200 mg/kg, i.p.) to pilocarpine-treated rats, significantly reduced lipid peroxides, total nitrate/nitrite, DNA fragmentation levels, and normalized catalase activity. Moreover, idebenone prevented pilocarpine-induced detrimental effects on brain hippocampal glutathione level, and Na(+), K(+)-ATPase enzyme activity in rats. Data obtained from the current investigation emphasized the critical role of oxidative stress in induction of seizures by pilocarpine and elucidated the prominent neuroprotective and antioxidant activities of idebenone in this model.
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110
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Kiss G, Konrad C, Pour-Ghaz I, Mansour JJ, Németh B, Starkov AA, Adam-Vizi V, Chinopoulos C. Mitochondrial diaphorases as NAD⁺ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition. FASEB J 2014; 28:1682-97. [PMID: 24391134 DOI: 10.1096/fj.13-243030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces high-energy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the α-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintaining the function of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. We addressed the source of the NAD(+) supply for KGDHC under anoxic conditions and inhibition of complex I. Using pharmacologic tools and specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity, we showed that mitochondrial diaphorases in the mouse liver contribute up to 81% to the NAD(+) pool during respiratory inhibition. Under these conditions, KGDHC's function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD(+) derived from diaphorases. Through this process, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by complex III of the respiratory chain.
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Affiliation(s)
- Gergely Kiss
- 1Department of Medical Biochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest 1094, Hungary.
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111
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Müller-Deile J, Schiffer M. The podocyte power-plant disaster and its contribution to glomerulopathy. Front Endocrinol (Lausanne) 2014; 5:209. [PMID: 25566185 PMCID: PMC4266017 DOI: 10.3389/fendo.2014.00209] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 11/21/2014] [Indexed: 11/22/2022] Open
Abstract
Proper podocyte function within the glomerulus demands a high and continuous energy supply that is mainly derived from the respiratory chain of the inner mitochondrial membrane. Dysregulations in the metabolic homeostasis of podocytes may result in podocyte damage and glomerular disease. This article highlights the current knowledge about podocyte energy supply by the respiratory chain. We review the regulation of mitochondrial oxidative metabolism with regard to podocytopathy and discuss the latest understanding of different mitochondrial dysfunctions of the podocyte in diabetic nephropathy and focal segmental glomerulosclerosis (FSGS). We discuss genetic forms of mitochondriopathy of the podocyte and end with recent knowledge about crosstalk between NADH and NADPH and potential therapeutic options for podocyte mitochondriopathy. We aim to raise awareness for the complex and interesting mechanisms of podocyte damage by impaired energy supply that, despite of novel findings in recent years, is poorly understood so far.
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Affiliation(s)
- Janina Müller-Deile
- Division of Nephrology and Hypertension, Department of Medicine, Hannover Medical School, Hannover, Germany
| | - Mario Schiffer
- Division of Nephrology and Hypertension, Department of Medicine, Hannover Medical School, Hannover, Germany
- *Correspondence: Mario Schiffer, Division of Nephrology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany e-mail:
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112
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Gueven N, Faldu D. Therapeutic strategies for Leber's hereditary optic neuropathy: A current update. Intractable Rare Dis Res 2013; 2:130-5. [PMID: 25343117 PMCID: PMC4204556 DOI: 10.5582/irdr.2013.v2.4.130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 11/05/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a rare mitochondrial retinopathy, caused by mutations in subunits of complex I of the respiratory chain, which leads to elevated levels of oxidative stress and an insufficient energy supply. This molecular pathology is thought to be responsible for the dysfunction and eventual apoptotic loss of retinal ganglion cells in the eye, which ultimately results in blindness. Many strategies, ranging from neuroprotectants, antioxidants, anti-apoptotic- and anti-inflammatory compounds have been tested with mixed results. Currently, the most promising compounds are short-chain quinones that have been shown to protect the vision of LHON patients during the early stages of the disease. This commentary gives a brief overview on the current status of tested therapeutics and also addresses future developments such as the use of gene therapy that hopefully will provide safe and efficient therapy options for all LHON patients.
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Affiliation(s)
- Nuri Gueven
- School of Pharmacy, University of Tasmania, Hobart, Australia
- Address correspondence to: Dr. Nuri Gueven, School of Pharmacy, University of Tasmania, Private Bag 26, Hobart, TAS 7001, Australia. E-mail:
| | - Dharmesh Faldu
- School of Pharmacy, University of Tasmania, Hobart, Australia
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113
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Barbosa DJ, Capela JP, Silva R, Vilas-Boas V, Ferreira LM, Branco PS, Fernandes E, Bastos MDL, Carvalho F. The mixture of “ecstasy” and its metabolites is toxic to human SH-SY5Y differentiated cells at in vivo relevant concentrations. Arch Toxicol 2013; 88:455-73. [PMID: 24101030 DOI: 10.1007/s00204-013-1120-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 08/22/2013] [Indexed: 12/21/2022]
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114
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Buyse GM, Goemans N, van den Hauwe M, Meier T. Effects of glucocorticoids and idebenone on respiratory function in patients with duchenne muscular dystrophy. Pediatr Pulmonol 2013; 48:912-20. [PMID: 23129412 DOI: 10.1002/ppul.22688] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/30/2012] [Accepted: 08/31/2012] [Indexed: 02/03/2023]
Abstract
In Duchenne muscular dystrophy (DMD) progressive weakness of respiratory muscles leads to a restrictive pulmonary syndrome that contributes to early morbidity and mortality. Currently no curative treatment exists for DMD. In a Phase II randomized placebo-controlled study (DELPHI) in 21 DMD boys at age 8-16 years, idebenone (450 mg/d) showed trends of efficacy for cardiac and respiratory endpoints. Since the DELPHI study population comprised both glucocorticoid-naïve subjects and glucocorticoid-users, we now report a post-hoc analysis investigating the effects of glucocorticoids and idebenone on markers of respiratory weakness, particularly peak expiratory flow (PEF) percent predicted (PEF%p). Baseline values of PEF%p correlated well with the percent predicted values for maximal inspiratory mouth pressure (MIP%p), forced vital capacity (FVC%p), and forced expired volume in 1 sec (FEV1%p). Baseline PEF%p and FVC%p were significantly higher in patients on concomitant glucocorticoids compared to glucocorticoid-naïve patients. In the latter subgroup, idebenone caused a 8.0 ± 12.1% improvement in PEF%p, whilst patients on placebo declined by -12.3 ± 17.9% (P < 0.05) in the course of the 12 month study. In patients receiving concomitant glucocorticoids, PEF%p remained stable (-0.4 ± 14.6%) in the idebenone group compared to a decline by -6.2 ± 12.4% (P = 0.24) in the placebo group. Idebenone showed a trend for efficacy on FVC%p only in glucocorticoid-naïve patients. Because of the study limitations, these data are exploratory and preclude any firm conclusions. In conclusion, PEF appears to be a sensitive respiratory function parameter that could be a valid and clinically relevant endpoint in intervention studies in DMD. In DELPHI the effect size of idebenone on PEF%p was significantly larger in steroid-naive patients, possibly indicating a maximum treatment effect reached by steroids or steroid-mediated suppression of idebenone's effects. The impact of standard care glucocorticoids on respiratory function will have to be considered in the planning of future interventional trials in DMD.
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Affiliation(s)
- Gunnar M Buyse
- Department of Child Neurology, University Hospitals Leuven, Belgium.
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115
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Abstract
Background: The authors investigated the correlation of protan and tritan color vision with disease characteristics in Leber hereditary optic neuropathy (LHON). The authors also characterized the therapeutic potential of idebenone in protecting patients from developing dyschromatopsia in LHON. Methods: Color contrast data of 39 LHON patients participating in a randomized, double-blind placebo-controlled intervention study were evaluated. Patients reported disease onset <5 years before enrolment and were genetically confirmed. Protan and tritan color contrast sensitivity was measured using a computer graphics method in patients receiving idebenone (Catena; 900 mg/d; N = 28) or placebo (N = 11) for 6 months. Results: Mean age of patients was 28.1 years, 87.2% were men, 76.9% carried the m11778G>A mutation, and mean duration since onset was 2 years. Assessing protan and tritan color vision at baseline revealed a high degree of color confusion even in young patients (<25 years) and with a short history of disease (<1 year). Treatment with idebenone improved tritan color vision compared with placebo (P = 0.008 at week 24); a similar trend was seen for protan. The effect of idebenone was most prominent in patients with discordant visual acuity (interocular difference of logMAR >0.2). In this subgroup, the treatment effect at week 24 was 20.4% (P = 0.005) in favor of idebenone for the tritan color domain and 13.5% (P = 0.067) for the protan domain. Conclusion: This study confirms that protan and tritan color confusion is an early symptom in LHON. Treatment with idebenone can protect from loss of color vision, particularly in patients who are at imminent risk of further vision loss.
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116
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Lovern D, Marbois B. Does menaquinone participate in brain astrocyte electron transport? Med Hypotheses 2013; 81:587-91. [PMID: 23910074 DOI: 10.1016/j.mehy.2013.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 06/25/2013] [Accepted: 07/03/2013] [Indexed: 02/03/2023]
Abstract
UNLABELLED Quinone compounds act as membrane resident carriers of electrons between components of the electron transport chain in the periplasmic space of prokaryotes and in the mitochondria of eukaryotes. Vitamin K is a quinone compound in the human body in a storage form as menaquinone (MK); distribution includes regulated amounts in mitochondrial membranes. The human brain, which has low amounts of typical vitamin K dependent function (e.g., gamma carboxylase) has relatively high levels of MK, and different regions of brain have different amounts. Coenzyme Q (Q), is a quinone synthesized de novo, and the levels of synthesis decline with age. The levels of MK are dependent on dietary intake and generally increase with age. MK has a characterized role in the transfer of electrons to fumarate in prokaryotes. A newly recognized fumarate cycle has been identified in brain astrocytes. The MK precursor menadione has been shown to donate electrons directly to mitochondrial complex III. HYPOTHESIS Vitamin K compounds function in the electron transport chain of human brain astrocytes.
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Affiliation(s)
- Douglas Lovern
- BioMérieux, 100 Rodolphe Dr., Durham, NC 27712, United States
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Kim J, Kim SK, Kim HK, Mattson MP, Hyun DH. Mitochondrial function in human neuroblastoma cells is up-regulated and protected by NQO1, a plasma membrane redox enzyme. PLoS One 2013; 8:e69030. [PMID: 23874855 PMCID: PMC3708898 DOI: 10.1371/journal.pone.0069030] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 06/06/2013] [Indexed: 12/21/2022] Open
Abstract
Background Recent findings suggest that NADH-dependent enzymes of the plasma membrane redox system (PMRS) play roles in the maintenance of cell bioenergetics and oxidative state. Neurons and tumor cells exhibit differential vulnerability to oxidative and metabolic stress, with important implications for the development of therapeutic interventions that promote either cell survival (neurons) or death (cancer cells). Methods and Findings Here we used human neuroblastoma cells with low or high levels of the PMRS enzyme NADH-quinone oxidoreductase 1 (NQO1) to investigate how the PMRS modulates mitochondrial functions and cell survival. Cells with elevated NQO1 levels exhibited higher levels of oxygen consumption and ATP production, and lower production of reactive oxygen species. Cells overexpressing NQO1 were more resistant to being damaged by the mitochondrial toxins rotenone and antimycin A, and exhibited less oxidative/nitrative damage and less apoptotic cell death. Cells with basal levels of NQO1 resulted in increased oxidative damage to proteins and cellular vulnerability to mitochondrial toxins. Thus, mitochondrial functions are enhanced and oxidative stress is reduced as a result of elevated PMRS activity, enabling cells to maintain redox homeostasis under conditions of metabolic and energetic stress. Conclusion These findings suggest that NQO1 is a potential target for the development of therapeutic agents for either preventing neuronal degeneration or promoting the death of neural tumor cells.
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Affiliation(s)
- Jiyeong Kim
- Department of Life Science, College of Natural Sciences, Ewha Womans University, Seoul, South Korea
| | - Su-Kyung Kim
- Department of Life Science, College of Natural Sciences, Ewha Womans University, Seoul, South Korea
| | - Hwa-Kyung Kim
- Department of Life Science, College of Natural Sciences, Ewha Womans University, Seoul, South Korea
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Dong-Hoon Hyun
- Department of Life Science, College of Natural Sciences, Ewha Womans University, Seoul, South Korea
- * E-mail:
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118
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Maresca A, la Morgia C, Caporali L, Valentino ML, Carelli V. The optic nerve: a "mito-window" on mitochondrial neurodegeneration. Mol Cell Neurosci 2013; 55:62-76. [PMID: 22960139 PMCID: PMC3629569 DOI: 10.1016/j.mcn.2012.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 01/16/2023] Open
Abstract
Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
| | | | | | | | - Valerio Carelli
- Corresponding author at: IRCCS Institute of Neurological Sciences of Bologna, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. Fax: + 39 051 2092751.
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Nikiforova AB, Fadeev RS, Kruglov AG. Rapid fluorescent visualization of multiple NAD(P)H oxidoreductases in homogenate, permeabilized cells, and tissue slices. Anal Biochem 2013; 440:189-96. [PMID: 23747529 DOI: 10.1016/j.ab.2013.05.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 11/27/2022]
Abstract
Intracellular NAD(P)H oxidoreductases are a class of diverse enzymes that are the key players in a number of vital processes. The method we present and validate here is based on the ability of many NAD(P)H oxidoreductases to reduce the superoxide probe lucigenin, which is structurally similar to flavins, to its highly fluorescent water-insoluble derivative dimethylbiacridene. Two modifications of the method are proposed: (i) an express method for tissue homogenate and permeabilized cells in suspensions and (ii) a standard procedure for cells in culture and acute thin tissue slices. The method allows one to assess, visualize, and localize, using fluorescent markers of cellular compartments, multiple NADH and NADPH oxidoreductase activities. The application of selective inhibitors (e.g., VAS2870, a NOX2 inhibitor; plumbagin, a NOX4 inhibitor) allows one to distinguish and compare specific NAD(P)H oxidoreductase activities in cells and tissues and to attribute them to known enzymes. The method is simple, rapid, and flexible. It can be easily adapted to a variety of tasks. It will be useful for investigations of the role of various NAD(P)H oxidoreductases in a number of physiological and pathophysiological processes.
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Affiliation(s)
- Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
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120
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Iyer S. Novel therapeutic approaches for Leber's hereditary optic neuropathy. DISCOVERY MEDICINE 2013; 15:141-149. [PMID: 23545042 PMCID: PMC5652312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Many human childhood mitochondrial disorders result from abnormal mitochondrial DNA (mtDNA) and altered bioenergetics. These abnormalities span most of the mtDNA, demonstrating that there are no "unique" positions on the mitochondrial genome that when deleted or mutated produce a disease phenotype. This diversity implies that the relationship between mitochondrial genotype and clinical phenotype is very complex. The origins of clinical phenotypes are thus unclear, fundamentally difficult-to-treat, and are usually clinically devastating. Current treatment is largely supportive and the disorders progress relentlessly causing significant morbidity and mortality. Vitamin supplements and pharmacological agents have been used in isolated cases and clinical trials, but the efficacy of these interventions is unclear. In spite of recent advances in the understanding of the pathogenesis of mitochondrial diseases, a cure remains elusive. An optimal cure would be gene therapy, which involves introducing the missing gene(s) into the mitochondria to complement the defect. Our recent research results indicate the feasibility of an innovative protein-transduction ("protofection") technology, consisting of a recombinant mitochondrial transcription factor A (TFAM) that avidly binds mtDNA and permits efficient targeting into mitochondria in situ and in vivo. Thus, the development of gene therapy for treating mitochondrial disease offers promise, because it may circumvent the clinical abnormalities and the current inability to treat individual disorders in affected individuals. This review aims to focus on current treatment options and future therapeutics in mitochondrial disease treatment with a special emphasis on Leber's hereditary optic neuropathy.
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Affiliation(s)
- Shilpa Iyer
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284, USA.
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121
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Gueven N, Faldu D. Idebenone treatment in Leber's hereditary optic neuropathy: rationale and efficacy. Expert Opin Orphan Drugs 2013. [DOI: 10.1517/21678707.2013.772894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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122
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Klopstock T, Metz G, Yu-Wai-Man P, Büchner B, Gallenmüller C, Bailie M, Nwali N, Griffiths PG, von Livonius B, Reznicek L, Rouleau J, Coppard N, Meier T, Chinnery PF. Persistence of the treatment effect of idebenone in Leber's hereditary optic neuropathy. ACTA ACUST UNITED AC 2013; 136:e230. [PMID: 23388409 PMCID: PMC3572931 DOI: 10.1093/brain/aws279] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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123
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124
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Barboni P, Valentino ML, La Morgia C, Carbonelli M, Savini G, De Negri A, Simonelli F, Sadun F, Caporali L, Maresca A, Liguori R, Baruzzi A, Zeviani M, Carelli V. Idebenone treatment in patients with OPA1-mutant dominant optic atrophy. Brain 2013; 136:e231. [PMID: 23388408 DOI: 10.1093/brain/aws280] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024] Open
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125
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Kohonen P, Benfenati E, Bower D, Ceder R, Crump M, Cross K, Grafström RC, Healy L, Helma C, Jeliazkova N, Jeliazkov V, Maggioni S, Miller S, Myatt G, Rautenberg M, Stacey G, Willighagen E, Wiseman J, Hardy B. The ToxBank Data Warehouse: Supporting the Replacement of In Vivo Repeated Dose Systemic Toxicity Testing. Mol Inform 2013; 32:47-63. [PMID: 27481023 DOI: 10.1002/minf.201200114] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 11/27/2012] [Indexed: 12/12/2022]
Abstract
The aim of the SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing-1) research cluster, comprised of seven EU FP7 Health projects co-financed by Cosmetics Europe, is to generate a proof-of-concept to show how the latest technologies, systems toxicology and toxicogenomics can be combined to deliver a test replacement for repeated dose systemic toxicity testing on animals. The SEURAT-1 strategy is to adopt a mode-of-action framework to describe repeated dose toxicity, combining in vitro and in silico methods to derive predictions of in vivo toxicity responses. ToxBank is the cross-cluster infrastructure project whose activities include the development of a data warehouse to provide a web-accessible shared repository of research data and protocols, a physical compounds repository, reference or "gold compounds" for use across the cluster (available via wiki.toxbank.net), and a reference resource for biomaterials. Core technologies used in the data warehouse include the ISA-Tab universal data exchange format, REpresentational State Transfer (REST) web services, the W3C Resource Description Framework (RDF) and the OpenTox standards. We describe the design of the data warehouse based on cluster requirements, the implementation based on open standards, and finally the underlying concepts and initial results of a data analysis utilizing public data related to the gold compounds.
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Affiliation(s)
| | | | | | | | | | | | | | - Lyn Healy
- National Institute for Biological Standards and Control, Potters Bar, UK
| | | | | | | | - Silvia Maggioni
- Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | | | | | | | - Glyn Stacey
- National Institute for Biological Standards and Control, Potters Bar, UK
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126
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Yamakoshi H, Dodo K, Palonpon A, Ando J, Fujita K, Kawata S, Sodeoka M. Alkyne-tag Raman imaging for visualization of mobile small molecules in live cells. J Am Chem Soc 2012. [PMID: 23198907 DOI: 10.1021/ja308529n] [Citation(s) in RCA: 290] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alkyne has a unique Raman band that does not overlap with Raman scattering from any endogenous molecule in live cells. Here, we show that alkyne-tag Raman imaging (ATRI) is a promising approach for visualizing nonimmobilized small molecules in live cells. An examination of structure-Raman shift/intensity relationships revealed that alkynes conjugated to an aromatic ring and/or to a second alkyne (conjugated diynes) have strong Raman signals in the cellular silent region and can be excellent tags. Using these design guidelines, we synthesized and imaged a series of alkyne-tagged coenzyme Q (CoQ) analogues in live cells. Cellular concentrations of diyne-tagged CoQ analogues could be semiquantitatively estimated. Finally, simultaneous imaging of two small molecules, 5-ethynyl-2'-deoxyuridine (EdU) and a CoQ analogue, with distinct Raman tags was demonstrated.
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Affiliation(s)
- Hiroyuki Yamakoshi
- Sodeoka Live Cell Chemistry Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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127
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He T, Banach-Latapy A, Vernis L, Dardalhon M, Chanet R, Huang ME. Peroxiredoxin 1 knockdown potentiates β-lapachone cytotoxicity through modulation of reactive oxygen species and mitogen-activated protein kinase signals. Carcinogenesis 2012; 34:760-9. [PMID: 23239746 DOI: 10.1093/carcin/bgs389] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Peroxiredoxin (Prx) 1 is a member of the thiol-specific peroxidases family and plays diverse roles such as H2O2 scavenger, redox signal transducer and molecular chaperone. Prx1 has been reported to be involved in protecting cancer cells against various therapeutic challenges. We investigated how modulations of intracellular redox system affect cancer cell sensitivity to reactive oxygen species (ROS)-generating drugs. We observed that stable and transient Prx1 knockdown significantly enhanced HeLa cell sensitivity to β-lapachone (β-lap), a potential anticancer agent. Prx1 knockdown markedly potentiated 2 µM β-lap-induced cytotoxicity through ROS accumulation. This effect was largely NAD(P)H:quinone oxidoreductase 1 dependent and associated with a decrease in poly(ADP-ribose) polymerase 1 protein levels, phosphorylation of JNK, p38 and Erk proteins in mitogen-activated protein kinase (MAPK) pathways and a decrease in thioredoxin 1 (Trx1) protein levels. Trx1 serves as an electron donor for Prx1 and is overexpressed in Prx1 knockdown cells. Based on the fact that Prx1 is a major ROS scavenger and a partner of at least ASK1 and JNK, two key components of MAPK pathways, we propose that Prx1 knockdown-induced sensitization to β-lap is achieved through combined action of accumulation of ROS and enhancement of MAPK pathway activation, leading to cell apoptosis. These data support the view that modulation of intracellular redox state could be an alternative approach to enhance cancer cell sensitivity to ROS-generating drugs or to overcome some types of drug resistance.
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Affiliation(s)
- Tiantian He
- Centre National de la Recherche Scientifique, UMR 3348 Genotoxic Stress and Cancer, Orsay, France
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128
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Carbone C, Pignatello R, Musumeci T, Puglisi G. Chemical and technological delivery systems for idebenone: a review of literature production. Expert Opin Drug Deliv 2012; 9:1377-92. [DOI: 10.1517/17425247.2012.724396] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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129
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Idebenone protects against retinal damage and loss of vision in a mouse model of Leber's hereditary optic neuropathy. PLoS One 2012; 7:e45182. [PMID: 23028832 PMCID: PMC3445472 DOI: 10.1371/journal.pone.0045182] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/14/2012] [Indexed: 11/24/2022] Open
Abstract
Leber’s hereditary optic neuropathy (LHON) is an inherited disease caused by mutations in complex I of the mitochondrial respiratory chain. The disease is characterized by loss of central vision due to retinal ganglion cell (RGC) dysfunction and optic nerve atrophy. Despite progress towards a better understanding of the disease, no therapeutic treatment is currently approved for this devastating disease. Idebenone, a short-chain benzoquinone, has shown promising evidence of efficacy in protecting vision loss and in accelerating recovery of visual acuity in patients with LHON. It was therefore of interest to study suitable LHON models in vitro and in vivo to identify anatomical correlates for this protective activity. At nanomolar concentrations, idebenone protected the rodent RGC cell line RGC-5 against complex I dysfunction in vitro. Consistent with the reported dosing and observed effects in LHON patients, we describe that in mice, idebenone penetrated into the eye at concentrations equivalent to those which protected RGC-5 cells from complex I dysfunction in vitro. Consequently, we next investigated the protective effect of idebenone in a mouse model of LHON, whereby mitochondrial complex I dysfunction was caused by exposure to rotenone. In this model, idebenone protected against the loss of retinal ganglion cells, reduction in retinal thickness and gliosis. Furthermore, consistent with this protection of retinal integrity, idebenone restored the functional loss of vision in this disease model. These results support the pharmacological activity of idebenone and indicate that idebenone holds potential as an effective treatment for vision loss in LHON patients.
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130
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Abstract
The hereditary optic neuropathies are inherited disorders in which optic nerve dysfunction is a prominent feature in the phenotypic expression of disease. Optic neuropathy may be primarily an isolated finding, such as in Leber hereditary optic neuropathy and dominant optic atrophy, or part of a multisystem disorder. The pathophysiological mechanisms underlying the hereditary optic neuropathies involve mitochondrial dysfunction owing to mutations in mitochondrial or nuclear DNA that encodes proteins essential to mitochondrial function. Effective treatments are limited, and current management includes therapies directed at enhancing mitochondrial function and preventing oxidative damage, as well as genetic counselling, and supportive and symptomatic measures. New therapies, including gene therapy, are emerging via animal models and human clinical trials. Leber hereditary optic neuropathy, in particular, provides a unique model for testing promising treatments owing to its characteristic sequential bilateral involvement and the accessibility of target tissue within the eye. Lessons learned from treatment of the hereditary optic neuropathies may have therapeutic implications for other disorders of presumed mitochondrial dysfunction. In this Review, the natural history of the common inherited optic neuropathies, the presumed pathogenesis of several of these disorders, and the literature to date regarding potential therapies are summarized.
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Affiliation(s)
- Nancy J Newman
- Neuro-ophthalmology Unit, Department of Ophthalmology, Neurology and Neurological Surgery, Emory University School of Medicine, 1365-B Clifton Road NE, Atlanta, GA 30322, USA
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131
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Disorders of the optic nerve in mitochondrial cytopathies: new ideas on pathogenesis and therapeutic targets. Curr Neurol Neurosci Rep 2012; 12:308-17. [PMID: 22392506 PMCID: PMC3342502 DOI: 10.1007/s11910-012-0260-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondrial cytopathies are a heterogeneous group of human disorders triggered by disturbed mitochondrial function. This can be due to primary mitochondrial DNA mutations or nuclear defects affecting key components of the mitochondrial machinery. Optic neuropathy is a frequent disease manifestation and the degree of visual failure can be profound, with a severe impact on the patient’s quality of life. This review focuses on the major mitochondrial disorders exhibiting optic nerve involvement, either as the defining clinical feature or as an additional component of a more extensive phenotype. Over the past decade, significant progress has been achieved in our basic understanding of Leber hereditary optic neuropathy and autosomal-dominant optic atrophy—the two classical paradigms for these mitochondrial optic neuropathies. There are currently limited treatments for these blinding ocular disorders and, ultimately, the aim is to translate these major advances into tangible benefits for patients and their families.
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132
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Analysis of the structural and mechanistic factors in antioxidants that preserve mitochondrial function and confer cytoprotection. Bioorg Med Chem 2012; 20:5188-201. [DOI: 10.1016/j.bmc.2012.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 06/27/2012] [Accepted: 07/04/2012] [Indexed: 12/31/2022]
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133
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Lin HZ, Pang CY, Chen SP, Tsai RK. Vision improvement in a Taiwanese (Han Chinese) family with Leber's hereditary optic neuropathy. Kaohsiung J Med Sci 2012; 28:679-82. [PMID: 23217361 DOI: 10.1016/j.kjms.2012.04.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 10/26/2011] [Indexed: 11/16/2022] Open
Abstract
In this report, we describe a Taiwanese (Han Chinese) family with Leber's hereditary optic neuropathy. The family carried a mitochondrial DNA mutation (mtDNA m.14484T>C) associated with spontaneous visual improvement. A 15-year-old boy from this family was diagnosed with Leber's hereditary optic neuropathy 6 months after losing his vision. His vision recovered after 8 months of supportive treatment. His mother, older brother, and two sisters also had the same mutation and had previously experienced vision loss. In this family, there was no male predominance.
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Affiliation(s)
- Hong-Zin Lin
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
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134
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Erb M, Hoffmann-Enger B, Deppe H, Soeberdt M, Haefeli RH, Rummey C, Feurer A, Gueven N. Features of idebenone and related short-chain quinones that rescue ATP levels under conditions of impaired mitochondrial complex I. PLoS One 2012; 7:e36153. [PMID: 22558363 PMCID: PMC3338594 DOI: 10.1371/journal.pone.0036153] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 03/27/2012] [Indexed: 12/14/2022] Open
Abstract
Short-chain quinones have been investigated as therapeutic molecules due to their ability to modulate cellular redox reactions, mitochondrial electron transfer and oxidative stress, which are pathologically altered in many mitochondrial and neuromuscular disorders. Recently, we and others described that certain short-chain quinones are able to bypass a deficiency in complex I by shuttling electrons directly from the cytoplasm to complex III of the mitochondrial respiratory chain to produce ATP. Although this energy rescue activity is highly interesting for the therapy of disorders associated with complex I dysfunction, no structure-activity-relationship has been reported for short-chain quinones so far. Using a panel of 70 quinones, we observed that the capacity for this cellular energy rescue as well as their effect on lipid peroxidation was influenced more by the physicochemical properties (in particular logD) of the whole molecule than the quinone moiety itself. Thus, the observed correlations allow us to explain the differential biological activities and therapeutic potential of short-chain quinones for the therapy of disorders associated with mitochondrial complex I dysfunction and/or oxidative stress.
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Affiliation(s)
- Michael Erb
- Santhera Pharmaceuticals, Liestal, Switzerland
| | | | | | | | - Roman H. Haefeli
- Santhera Pharmaceuticals, Liestal, Switzerland
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Nuri Gueven
- Santhera Pharmaceuticals, Liestal, Switzerland
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135
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Smith RAJ, Hartley RC, Cochemé HM, Murphy MP. Mitochondrial pharmacology. Trends Pharmacol Sci 2012; 33:341-52. [PMID: 22521106 DOI: 10.1016/j.tips.2012.03.010] [Citation(s) in RCA: 360] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/28/2012] [Accepted: 03/13/2012] [Indexed: 12/13/2022]
Abstract
Mitochondria are being recognized as key factors in many unexpected areas of biomedical science. In addition to their well-known roles in oxidative phosphorylation and metabolism, it is now clear that mitochondria are also central to cell death, neoplasia, cell differentiation, the innate immune system, oxygen and hypoxia sensing, and calcium metabolism. Disruption to these processes contributes to a range of human pathologies, making mitochondria a potentially important, but currently seemingly neglected, therapeutic target. Mitochondrial dysfunction is often associated with oxidative damage, calcium dyshomeostasis, defective ATP synthesis, or induction of the permeability transition pore. Consequently, therapies designed to prevent these types of damage are beneficial and can be used to treat many diverse and apparently unrelated indications. Here we outline the biological properties that make mitochondria important determinants of health and disease, and describe the pharmacological strategies being developed to address mitochondrial dysfunction.
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Affiliation(s)
- Robin A J Smith
- Department of Chemistry, University of Otago, Box 56, Dunedin, New Zealand
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136
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Yu-Wai-Man P, Chinnery PF. Leber Hereditary Optic Neuropathy - Therapeutic Challenges and Early Promise. Taiwan J Ophthalmol 2011; 1:12-15. [PMID: 25729642 PMCID: PMC4340545 DOI: 10.1016/j.tjo.2011.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Abstract
Leber hereditary optic neuropathy (LHON) is the most common primary mitochondrial DNA (mtDNA) disorder in the general population. It is an important cause of severe, usually irreversible, visual loss among young adults with a peak age of onset in the second and third decades of life. Management is currently mostly supportive but recent developments in LHON research are pointing the way towards more effective treatments for this blinding mitochondrial disorder.
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Affiliation(s)
- Patrick Yu-Wai-Man
- Mitochondrial Research Group, Institute of Genetic Medicine, Centre for Life, Newcastle University, NE1 3BZ, UK
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK
| | - Patrick F. Chinnery
- Mitochondrial Research Group, Institute of Genetic Medicine, Centre for Life, Newcastle University, NE1 3BZ, UK
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK
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137
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Giorgio V, Petronilli V, Ghelli A, Carelli V, Rugolo M, Lenaz G, Bernardi P. The effects of idebenone on mitochondrial bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:363-9. [PMID: 22086148 PMCID: PMC3265671 DOI: 10.1016/j.bbabio.2011.10.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/27/2011] [Accepted: 10/28/2011] [Indexed: 12/17/2022]
Abstract
We have studied the effects of idebenone on mitochondrial function in cybrids derived from one normal donor (HQB17) and one patient harboring the G3460A/MT-ND1 mutation of Leber's Hereditary Optic Neuropathy (RJ206); and in XTC.UC1 cells bearing a premature stop codon at aminoacid 101 of MT-ND1 that hampers complex I assembly. Addition of idebenone to HQB17 cells caused mitochondrial depolarization and NADH depletion, which were inhibited by cyclosporin (Cs) A and decylubiquinone, suggesting an involvement of the permeability transition pore (PTP). On the other hand, addition of dithiothreitol together with idebenone did not cause PTP opening and allowed maintenance of the mitochondrial membrane potential even in the presence of rotenone. Addition of dithiothreitol plus idebenone, or of idebenol, to HQB17, RJ206 and XTC.UC1 cells sustained membrane potential in intact cells and ATP synthesis in permeabilized cells even in the presence of rotenone and malonate, and restored a good level of coupled respiration in complex I-deficient XTC.UC1 cells. These findings demonstrate that idebenol can feed electrons at complex III. If the quinone is maintained in the reduced state, a task that in some cell types appears to be performed by dicoumarol-sensitive NAD(P)H:quinone oxidoreductase 1 [Haefeli et al. (2011) PLoS One 6, e17963], electron transfer to complex III may allow reoxidation of NADH in complex I deficiencies.
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Affiliation(s)
- Valentina Giorgio
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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Klopstock T, Yu-Wai-Man P, Dimitriadis K, Rouleau J, Heck S, Bailie M, Atawan A, Chattopadhyay S, Schubert M, Garip A, Kernt M, Petraki D, Rummey C, Leinonen M, Metz G, Griffiths PG, Meier T, Chinnery PF. A randomized placebo-controlled trial of idebenone in Leber's hereditary optic neuropathy. ACTA ACUST UNITED AC 2011; 134:2677-86. [PMID: 21788663 PMCID: PMC3170530 DOI: 10.1093/brain/awr170] [Citation(s) in RCA: 340] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Major advances in understanding the pathogenesis of inherited metabolic disease caused by mitochondrial DNA mutations have yet to translate into treatments of proven efficacy. Leber’s hereditary optic neuropathy is the most common mitochondrial DNA disorder causing irreversible blindness in young adult life. Anecdotal reports support the use of idebenone in Leber’s hereditary optic neuropathy, but this has not been evaluated in a randomized controlled trial. We conducted a 24-week multi-centre double-blind, randomized, placebo-controlled trial in 85 patients with Leber’s hereditary optic neuropathy due to m.3460G>A, m.11778G>A, and m.14484T>C or mitochondrial DNA mutations. The active drug was idebenone 900 mg/day. The primary end-point was the best recovery in visual acuity. The main secondary end-point was the change in best visual acuity. Other secondary end-points were changes in visual acuity of the best eye at baseline and changes in visual acuity for both eyes in each patient. Colour-contrast sensitivity and retinal nerve fibre layer thickness were measured in subgroups. Idebenone was safe and well tolerated. The primary end-point did not reach statistical significance in the intention to treat population. However, post hoc interaction analysis showed a different response to idebenone in patients with discordant visual acuities at baseline; in these patients, all secondary end-points were significantly different between the idebenone and placebo groups. This first randomized controlled trial in the mitochondrial disorder, Leber’s hereditary optic neuropathy, provides evidence that patients with discordant visual acuities are the most likely to benefit from idebenone treatment, which is safe and well tolerated.
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Affiliation(s)
- Thomas Klopstock
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
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Than TA, Lou H, Ji C, Win S, Kaplowitz N. Role of cAMP-responsive element-binding protein (CREB)-regulated transcription coactivator 3 (CRTC3) in the initiation of mitochondrial biogenesis and stress response in liver cells. J Biol Chem 2011; 286:22047-54. [PMID: 21536665 DOI: 10.1074/jbc.m111.240481] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Peroxisome proliferator-activated receptor α, coactivator 1α (PGC-1α) is the master regulator of mitochondrial biogenesis. PGC-1α expression is under the control of the transcription factor, cAMP-responsive element-binding protein (CREB). In searching for candidate transcription factors that mediate mitochondrial stress-initiated mitochondria-to-nucleus signaling in the regulation of mitochondrial biogenesis, we assessed the effect of silencing CREB-regulated transcription co-activators (CRTC). CRTC isoforms are co-activators of CREB-regulated transcription by a CREB phosphorylation-independent pathway. Using cultured HepG2 cells and primary mouse hepatocytes, we determined that mitochondrial stress imposed by the complex I inhibitor rotenone elicited mitochondrial biogenesis, which was dependent on an induction of PGC-1α, which was inhibited by silencing PGC-1α. PGC-1α induction in response to rotenone was inhibited by silencing the expression of CRTC3, which blocked downstream mitochondria biogenesis. In contrast, silencing CRTC2 did not affect the induction of this pathway in response to rotenone. Thus, CRTC3 plays a selective role in mitochondrial biogenesis in response to rotenone.
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Affiliation(s)
- Tin Aung Than
- University of Southern California Research Center for Liver Diseases, Southern California Research Center for Alcoholic, Liver and Pancreatic Disease, and Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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Oida T, Mimatsu K, Kawasaki A, Kano H, Kuboi Y, Aramaki O, Amano S. Long-term outcome of laparoscopic cystogastrostomy performed using a posterior approach with a stapling device. Dig Surg 2009; 26:110-4. [PMID: 19262059 DOI: 10.1159/000206144] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND Internal drainage of an acute pancreatic pseudocyst is indicated 6 weeks after its first detection. Laparoscopic treatment of pancreatic pseudocysts enables definitive drainage with faster recovery. Pseudocysts located adjacent to the posterior gastric wall are best drained by pseudocyst gastrostomy. Although the anterior approach for drainage has frequently been reported, reports on the posterior approach are rare. METHODS Seven patients underwent laparoscopic cystogastrostomy for pancreatic pseudocysts. The posterior approach that enables the direct visualization of the posterior gastric wall and pseudocyst was used, and the cyst was drained with a needle. After creating a sufficient drainage orifice, the cyst was thoroughly debrided. Cystogastrostomy was performed using the posterior approach with a stapling device. The insertion site of the stapling device closed using a hernia stapler. RESULTS Cystogastrostomy was performed using the posterior approach with a stapling device in all patients, without requiring conversion to the anterior approach or open surgery. There were neither operative complications nor late recurrences during the follow-up period (median 65 months). CONCLUSION Laparoscopic cystogastrostomy using the posterior approach, which facilitates adequate internal drainage, is a safe and feasible procedure for pancreatic pseudocyst, and it is not accompanied with a risk of recurrence in the long term.
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Affiliation(s)
- Takatsugu Oida
- Department of Surgery, Social Insurance Yokohama Central Hospital, Yokohama, Japan.
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