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Reshetnyak VI, Maev IV. New insights into the pathogenesis of primary biliary cholangitis asymptomatic stage. World J Gastroenterol 2023; 29:5292-5304. [PMID: 37899787 PMCID: PMC10600802 DOI: 10.3748/wjg.v29.i37.5292] [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] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/10/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023] Open
Abstract
Primary biliary cholangitis (PBC) is a chronic cholestatic progressive liver disease and one of the most important progressive cholangiopathies in adults. Damage to cholangiocytes triggers the development of intrahepatic cholestasis, which progresses to cirrhosis in the terminal stage of the disease. Accumulating data indicate that damage to biliary epithelial cells [(BECs), cholangiocytes] is most likely associated with the intracellular accumulation of bile acids, which have potent detergent properties and damaging effects on cell membranes. The mechanisms underlying uncontrolled bile acid intake into BECs in PBC are associated with pH change in the bile duct lumen, which is controlled by the bicarbonate (HCO3-) buffer system "biliary HCO3- umbrella". The impaired production and entry of HCO3- from BECs into the bile duct lumen is due to epigenetic changes in expression of the X-linked microRNA 506. Based on the growing body of knowledge on the molecular mechanisms of cholangiocyte damage in patients with PBC, we propose a hypothesis explaining the pathogenesis of the first morphologic (ductulopenia), immunologic (antimitochondrial autoantibodies) and clinical (weakness, malaise, rapid fatigue) signs of the disease in the asymptomatic stage. This review focuses on the consideration of these mechanisms.
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Affiliation(s)
- Vasiliy Ivanovich Reshetnyak
- Department of Propaedeutics of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Igor Veniaminovich Maev
- Department of Propaedeutics of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
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2
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Long DL, McCall CE, Poole LB. Glutathionylation of pyruvate dehydrogenase complex E2 and inflammatory cytokine production during acute inflammation are magnified by mitochondrial oxidative stress. Redox Biol 2023; 65:102841. [PMID: 37566945 PMCID: PMC10440583 DOI: 10.1016/j.redox.2023.102841] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/13/2023] Open
Abstract
Lipopolysaccharide (LPS) is a known inducer of inflammatory signaling which triggers generation of reactive oxygen species (ROS) and cell death in responsive cells like THP-1 promonocytes and freshly isolated human monocytes. A key LPS-responsive metabolic pivot point is the 9 MDa mitochondrial pyruvate dehydrogenase complex (PDC), which provides pyruvate dehydrogenase (E1), lipoamide-linked transacetylase (E2) and lipoamide dehydrogenase (E3) activities to produce acetyl-CoA from pyruvate. While phosphorylation-dependent decreases in PDC activity following LPS treatment or sepsis have been deeply investigated, redox-linked processes have received less attention. Data presented here demonstrate that LPS-induced reversible oxidation within PDC occurs in PDCE2 in both THP-1 cells and primary human monocytes. Knockout of PDCE2 by CRISPR and expression of FLAG-tagged PDCE2 in THP-1 cells demonstrated that LPS-induced glutathionylation is associated with wild type PDCE2 but not mutant protein lacking the lipoamide-linking lysine residues. Moreover, the mitochondrially-targeted electrophile MitoCDNB, which impairs both glutathione- and thioredoxin-based reductase systems, elevates ROS similar to LPS but does not cause PDCE2 glutathionylation. However, LPS and MitoCDNB together are highly synergistic for PDCE2 glutathionylation, ROS production, and cell death. Surprisingly, the two treatments together had differential effects on cytokine production; pro-inflammatory IL-1β production was enhanced by the co-treatment, while IL-10, an important anti-inflammatory cytokine, dropped precipitously compared to LPS treatment alone. This new information may expand opportunities to understand and modulate PDC redox status and activity and improve the outcomes of pathological inflammation.
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Affiliation(s)
- David L Long
- Department of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
| | - Charles E McCall
- Department of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
| | - Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
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3
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Roosterman D, Cottrell GS. Discovery of a second citric acid cycle complex. Heliyon 2023; 9:e15968. [PMID: 37251852 PMCID: PMC10209337 DOI: 10.1016/j.heliyon.2023.e15968] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023] Open
Abstract
Together, Nobel Prize honoured work, mathematics, physics and the laws of nature have drawn a concept of clockwise cycling carboxylic acids in Krebs' Citric Acid Cycle. A Citric Acid Cycle complex is defined by specific substrate, product and regulation. Recently, the Citric Acid Cycle 1.1 complex was introduced as an NAD+-regulated cycle with the substrate, lactic acid and the product, malic acid. Here, we introduce the concept of the Citric Acid Cycle 2.1 complex as an FAD-regulated cycle with the substrate, malic acid and the products, succinic acid or citric acid. The function of the Citric Acid Cycle 2.1 complex is to balance stress situations within the cell. We propose that the biological function of Citric Acid Cycle 2.1 in muscles is to accelerate recovery of ATP; whereas in white tissue adipocytes our testing of the theoretical concept led to the storage of energy as lipids.
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4
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Kim MJ, Sinam IS, Siddique Z, Jeon JH, Lee IK. The Link between Mitochondrial Dysfunction and Sarcopenia: An Update Focusing on the Role of Pyruvate Dehydrogenase Kinase 4. Diabetes Metab J 2023; 47:153-163. [PMID: 36635027 PMCID: PMC10040620 DOI: 10.4093/dmj.2022.0305] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/13/2022] [Indexed: 01/14/2023] Open
Abstract
Sarcopenia, defined as a progressive loss of muscle mass and function, is typified by mitochondrial dysfunction and loss of mitochondrial resilience. Sarcopenia is associated not only with aging, but also with various metabolic diseases characterized by mitochondrial dyshomeostasis. Pyruvate dehydrogenase kinases (PDKs) are mitochondrial enzymes that inhibit the pyruvate dehydrogenase complex, which controls pyruvate entry into the tricarboxylic acid cycle and the subsequent adenosine triphosphate production required for normal cellular activities. PDK4 is upregulated in mitochondrial dysfunction-related metabolic diseases, especially pathologic muscle conditions associated with enhanced muscle proteolysis and aberrant myogenesis. Increases in PDK4 are associated with perturbation of mitochondria-associated membranes and mitochondrial quality control, which are emerging as a central mechanism in the pathogenesis of metabolic disease-associated muscle atrophy. Here, we review how mitochondrial dysfunction affects sarcopenia, focusing on the role of PDK4 in mitochondrial homeostasis. We discuss the molecular mechanisms underlying the effects of PDK4 on mitochondrial dysfunction in sarcopenia and show that targeting mitochondria could be a therapeutic target for treating sarcopenia.
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Affiliation(s)
- Min-Ji Kim
- Department of Internal Medicine, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Ibotombi Singh Sinam
- Bio-Medical Research Institute, Kyungpook National University Hospital, Daegu, Korea
| | - Zerwa Siddique
- Department of Biomedical Science, Graduate School, Kyungpook National University, Daegu, Korea
- BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University, Daegu, Korea
| | - Jae-Han Jeon
- Department of Internal Medicine, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
- Corresponding author: In-Kyu Lee https://orcid.org/0000-0002-2261-7269 Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Korea E-mail:
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5
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Stacpoole PW, McCall CE. The pyruvate dehydrogenase complex: Life's essential, vulnerable and druggable energy homeostat. Mitochondrion 2023; 70:59-102. [PMID: 36863425 DOI: 10.1016/j.mito.2023.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [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: 08/02/2022] [Revised: 01/30/2023] [Accepted: 02/13/2023] [Indexed: 03/04/2023]
Abstract
Found in all organisms, pyruvate dehydrogenase complexes (PDC) are the keystones of prokaryotic and eukaryotic energy metabolism. In eukaryotic organisms these multi-component megacomplexes provide a crucial mechanistic link between cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle. As a consequence, PDCs also influence the metabolism of branched chain amino acids, lipids and, ultimately, oxidative phosphorylation (OXPHOS). PDC activity is an essential determinant of the metabolic and bioenergetic flexibility of metazoan organisms in adapting to changes in development, nutrient availability and various stresses that challenge maintenance of homeostasis. This canonical role of the PDC has been extensively probed over the past decades by multidisciplinary investigations into its causal association with diverse physiological and pathological conditions, the latter making the PDC an increasingly viable therapeutic target. Here we review the biology of the remarkable PDC and its emerging importance in the pathobiology and treatment of diverse congenital and acquired disorders of metabolic integration.
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Affiliation(s)
- Peter W Stacpoole
- Department of Medicine (Division of Endocrinology, Metabolism and Diabetes), and Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, FL, United States.
| | - Charles E McCall
- Department of Internal Medicine and Translational Sciences, and Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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Alfarsi A, Alfadhel M, Alameer S, Alhashem A, Tabarki B, Ababneh F, Al Fares A, Al Mutairi F. The phenotypic spectrum of dihydrolipoamide dehydrogenase deficiency in Saudi Arabia. Mol Genet Metab Rep 2021; 29:100817. [PMID: 34745891 PMCID: PMC8554626 DOI: 10.1016/j.ymgmr.2021.100817] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 11/28/2022] Open
Abstract
Background Dihydrolipoamide dehydrogenase deficiency (DLDD) is a rare metabolic disorder inherited in an autosomal recessive manner. This heterogeneous disease has a variable clinical presentation, onset, and biochemical markers. Materials and methods We retrospectively reviewed the clinical and molecular diagnosis of eight cases with DLDD from four referral centers in Saudi Arabia. Results Remarkably, we found hepatic involvement ranging from acute hepatic failure to chronic hepatitis in five patients. In addition, neurological disorders in the form of seizures, developmental delay, ataxia, hypotonia and psychomotor symptoms were found in five patients, two of them with a combination of hepatic and neurological symptoms. In addition, only one patient had recurrent episodes of hypoglycemia. While most patients had the hepatic form of homozygous variant c.685G > T in the DLD gene, one patient was found to have a novel variant c.623C > T that had neurological and hepatic symptoms. Conclusions We describe the largest reported DLDD cohort in the Saudi population. Clinical, biochemical, radiological, and molecular characterization was reviewed and no clear genotype-phenotype correlation was found in this cohort.
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Key Words
- BCAAs, Branched Chain Amino Acids
- BCKDH, Branched-chain a-keto acid dehydrogenase
- DCA, Dichloroacetate
- DLDD, Dihydrolipoamide Dehydrogenase Deficiency
- Dihydrolipoamide dehydrogenase deficiency
- Flavoprotein and E3
- Hypoglycemia
- IRB, Institutional Review Board
- KAIMRC, King Abdullah International Medical Research Centre
- Lactic acidosis
- MRI, Magnetic resonance imaging
- PDH, Pyruvate dehydrogenase
- Pyruvate dehydrogenase complex
- WES, Whole Exome Sequencing
- αKGDH, alpha-ketoglutarate dehydrogenase
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Affiliation(s)
- Anar Alfarsi
- Genetics & Precision Medicine Department, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Genetics & Precision Medicine Department, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Seham Alameer
- King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Jeddah, Saudi Arabia
| | - Amal Alhashem
- Division of Genetics, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.,Department of Anatomy and Cell biology, college of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Division of Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Faroug Ababneh
- Genetics & Precision Medicine Department, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Ahmed Al Fares
- King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,Division of Translational Pathology, Department of Pathology, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,Department of Pediatrics, College of Medicine, Qassim University, Buraidah, Saudi Arabia
| | - Fuad Al Mutairi
- Genetics & Precision Medicine Department, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Centre, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
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7
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Atkins R, Constantin-Teodosiu D, Varadhan KK, Constantin D, Lobo DN, Greenhaff PL. Major elective abdominal surgery acutely impairs lower limb muscle pyruvate dehydrogenase complex activity and mitochondrial function. Clin Nutr 2021; 40:1046-1051. [PMID: 32711950 PMCID: PMC7957361 DOI: 10.1016/j.clnu.2020.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND & AIMS This post hoc study aimed to determine whether major elective abdominal surgery had any acute impact on mitochondrial pyruvate dehydrogenase complex (PDC) activity and maximal mitochondrial ATP production rates (MAPR) in a large muscle group (vastus lateralis -VL) distant to the site of surgical trauma. METHODS Fifteen patients undergoing major elective open abdominal surgery were studied. Muscle biopsies were obtained after the induction of anesthesia from the VL immediately before and after surgery for the determination of PDC and maximal MAPR (utilizing a variety of energy substrates). RESULTS Muscle PDC activity was reduced by >50% at the end of surgery compared with pre-surgery (p < 0.05). Muscle MAPR were comprehensively suppressed by surgery for the substrate combinations: glutamate + succinate; glutamate + malate; palmitoylcarnitine + malate; and pyruvate + malate (all p < 0.05), and could not be explained by a lower mitochondrial yield. CONCLUSIONS PDC activity and mitochondrial ATP production capacity were acutely impaired in muscle distant to the site of surgical trauma. In keeping with the limited data available, we surmise these events resulted from the general anesthesia procedures employed and the surgery related trauma. These findings further the understanding of the acute dysregulation of mitochondrial function in muscle distant to the site of major surgical trauma in patients, and point to the combination of general anesthesia and trauma related inflammation as being drivers of muscle metabolic insult that warrants further investigation. CLINICAL TRIAL REGISTRATION Registered at (NCT01134809).
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Affiliation(s)
- Ryan Atkins
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Dumitru Constantin-Teodosiu
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Krishna K Varadhan
- Gastrointestinal Surgery, Nottingham Digestive Diseases Centre, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Despina Constantin
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Dileep N Lobo
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; Gastrointestinal Surgery, Nottingham Digestive Diseases Centre, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; National Institute of Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
| | - Paul L Greenhaff
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; National Institute of Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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8
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Abstract
According to data from the World Health Organization, cardiovascular diseases and cancer are the two leading causes of mortality in the world [1]. Despite the immense effort to study these diseases and the constant innovation in treatment modalities, the number of deaths associated with cardiovascular diseases and cancer is predicted to increase in the coming decades [1]. From 2008 to 2030, due to population growth and population aging in many parts of the world, the number of deaths caused by cancer globally is projected to increase by 45%, corresponding to an annual increase of around four million people [1]. For cardiovascular diseases, this number is six million people [1]. In the United States, treatments for these two diseases are among the most costly and result in a disproportionate impact on low- and middleincome people. As the fight against these fatal diseases continues, it is crucial that we continue our investigation and broaden our understanding of cancer and cardiovascular diseases to innovate our prognostic and treatment approaches. Even though cardiovascular diseases and cancer are usually studied independently [2-12], there are some striking overlaps between their metabolic behaviors and therapeutic targets, suggesting the potential application of cardiovascular disease treatments for cancer therapy. More specifically, both cancer and many cardiovascular diseases have an upregulated glutaminolysis pathway, resulting in low glutamine and high glutamate circulating levels. Similar treatment modalities, such as glutaminase (GLS) inhibition and glutamine supplementation, have been identified to target glutamine metabolism in both cancer and some cardiovascular diseases. Studies have also found similarities in lipid metabolism, specifically fatty acid oxidation (FAO) and synthesis. Pharmacological inhibition of FAO and fatty acid synthesis have proven effective against many cancer types as well as specific cardiovascular conditions. Many of these treatments have been tested in clinical trials, and some have been medically prescribed to patients to treat certain diseases, such as angina pectoris [13, 14]. Other metabolic pathways, such as tryptophan catabolism and pyruvate metabolism, were also dysregulated in both diseases, making them promising treatment targets. Understanding the overlapping traits exhibited by both cancer metabolism and cardiovascular disease metabolism can give us a more holistic view of how important metabolic dysregulation is in the progression of diseases. Using established links between these illnesses, researchers can take advantage of the discoveries from one field and potentially apply them to the other. In this chapter, we highlight some promising therapeutic discoveries that can support our fight against cancer, based on common metabolic traits displayed in both cancer and cardiovascular diseases.
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Affiliation(s)
- Giang Hoang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, USA
| | - Kiet Nguyen
- Department of Chemistry and Biology, Emory University, Atlanta, GA, USA
| | - Anne Le
- Department of Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD, USA.
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9
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Skalidis I, Tüting C, Kastritis PL. Unstructured regions of large enzymatic complexes control the availability of metabolites with signaling functions. Cell Commun Signal 2020; 18:136. [PMID: 32843078 PMCID: PMC7448341 DOI: 10.1186/s12964-020-00631-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/17/2020] [Indexed: 12/23/2022] Open
Abstract
Metabolites produced via traditional biochemical processes affect intracellular communication, inflammation, and malignancy. Unexpectedly, acetyl-CoA, α-ketoglutarate and palmitic acid, which are chemical species of reactions catalyzed by highly abundant, gigantic enzymatic complexes, dubbed as "metabolons", have broad "nonmetabolic" signaling functions. Conserved unstructured regions within metabolons determine the yield of these metabolites. Unstructured regions tether functional protein domains, act as spatial constraints to confine constituent enzyme communication, and, in the case of acetyl-CoA production, tend to be regulated by intricate phosphorylation patterns. This review presents the multifaceted roles of these three significant metabolites and describes how their perturbation leads to altered or transformed cellular function. Their dedicated enzymatic systems are then introduced, namely, the pyruvate dehydrogenase (PDH) and oxoglutarate dehydrogenase (OGDH) complexes, and the fatty acid synthase (FAS), with a particular focus on their structural characterization and the localization of unstructured regions. Finally, upstream metabolite regulation, in which spatial occupancy of unstructured regions within dedicated metabolons may affect metabolite availability and subsequently alter cell functions, is discussed. Video abstract.
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Affiliation(s)
- Ioannis Skalidis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
| | - Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany. .,Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany. .,ZIK HALOmem, Martin Luther University Halle-Wittenberg, Biozentrum, Room A.2.14, Weinbergweg 22, 06120, Halle/Saale, Germany.
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10
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Reiter RJ, Sharma R, Ma Q, Rorsales-Corral S, de Almeida Chuffa LG. Melatonin inhibits Warburg-dependent cancer by redirecting glucose oxidation to the mitochondria: a mechanistic hypothesis. Cell Mol Life Sci 2020; 77:2527-2542. [PMID: 31970423 DOI: 10.1007/s00018-019-03438-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [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: 10/03/2019] [Revised: 12/16/2019] [Accepted: 12/23/2019] [Indexed: 12/16/2022]
Abstract
Melatonin has the ability to intervene in the initiation, progression and metastasis of some experimental cancers. A large variety of potential mechanisms have been advanced to describe the metabolic and molecular events associated with melatonin's interactions with cancer cells. There is one metabolic perturbation that is common to a large number of solid tumors and accounts for the ability of cancer cells to actively proliferate, avoid apoptosis, and readily metastasize, i.e., they use cytosolic aerobic glycolysis (the Warburg effect) to rapidly generate the necessary ATP required for the high metabolic demands of the cancer cells. There are several drugs, referred to as glycolytic agents, that cause cancer cells to abandon aerobic glycolysis and shift to the more conventional mitochondrial oxidative phosphorylation for ATP synthesis as in normal cells. In doing so, glycolytic agents also inhibit cancer growth. Herein, we hypothesize that melatonin also functions as an inhibitor of cytosolic glycolysis in cancer cells using mechanisms, i.e., downregulation of the enzyme (pyruvate dehydrogenase kinase) that interferes with the conversion of pyruvate to acetyl CoA in the mitochondria, as do other glycolytic drugs. In doing so, melatonin halts the proliferative activity of cancer cells, reduces their metastatic potential and causes them to more readily undergo apoptosis. This hypothesis is discussed in relation to the previously published reports. Whereas melatonin is synthesized in the mitochondria of normal cells, we hypothesize that this synthetic capability is not present in cancer cell mitochondria because of the depressed acetyl CoA; acetyl CoA is necessary for the rate limiting enzyme in melatonin synthesis, arylalkylamine-N-acetyltransferase. Finally, the ability of melatonin to switch glucose oxidation from the cytosol to the mitochondria also explains how tumors that become resistant to conventional chemotherapies are re-sensitized to the same treatment when melatonin is applied.
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Affiliation(s)
- Russel J Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX, USA.
| | - Ramaswamy Sharma
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX, USA
| | - Qiang Ma
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX, USA
| | - Sergio Rorsales-Corral
- Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara, Mexico
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11
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Michno A, Grużewska K, Bielarczyk H, Zyśk M, Szutowicz A. Inhibition of pyruvate dehydrogenase complex activity by 3-bromopyruvate affects blood platelets responses in type 2 diabetes. Pharmacol Rep 2020; 72:225-37. [PMID: 32016856 DOI: 10.1007/s43440-019-00005-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 09/04/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hyperactivation of blood platelets is an essential factor in the pathomechanism of diabetes-evoked angiopathies. The aim of this work was to investigate whether blood platelets hyperactivation resulting from type 2 diabetic hyperglycaemia-increased pyruvate dehydrogenase complex activity and excessive acetyl-CoA accumulation may be brought to the normal range by the enzyme inhibitors. METHODS Platelets were isolated from the blood of 9 type 2 diabetic patients and 10 healthy donors. Effects of 3-bromopyruvate and 3-nitropropionate on pyruvate dehydrogenase complex (PDHC) and succinate dehydrogenase activities, as well as levels of acetyl-CoA, ATP, thiobarbituric acid reactive species and aggregation were assessed in non-activated and thrombin-activated platelets. RESULTS In type 2 diabetic patients fasting plasma glucose and fructosamine levels were 61 and 64% higher, respectively, than in the healthy group (p < 0.001). In non-activated diabetic platelets PDHC activity, PDHC-E2, acetyl-CoA and ATP levels were 66, 70, 68 and 60%, higher, respectively, than in platelets from healthy controls (p < 0.01). 3-bromopyruvate (0.1 mM) decreased pyruvate dehydrogenase activity in healthy and diabetic platelets by 42% and 59%, respectively. Similar inhibitory effects were observed for acetyl-CoA and ATP levels, aggregation and TBARS accumulation rates. Succinate dehydrogenase activity was inhibited by 3-nitropropionate (10 mM) to 38 and 41% of control values in healthy and diabetic platelets, respectively, but affected neither function nor acetyl-CoA metabolism in platelets of both groups. CONCLUSIONS These data indicate that inhibition of pyruvate dehydrogenase excessive activity in diabetic platelets by 3-bromopyruvate may normalise their functional parameters through adjustment of acetyl-CoA/ATP levels to control values. Platelets from blood of diabetic patients display higher activities of pyruvate dehydrogenase complex (PDHC), higher levels of dihydrolipoate transacetylase (DLAT, E2 subunit of PDHC) as well as higher levels of acetyl-CoA yielding greater ATP/ADP accumulation than in platelets of normoglycemic subjects. Therefore, in diabetic platelets, thrombin caused higher release of ATP/ADP triggering excessive production of reactive oxygen species (ROS) and stronger aggregation compared to control platelets. In diabetic platelets, relative excess of DLAT in PDHC made them highly susceptible to 3-bromopyruvate (3BrP) inhibition. Resulting limitation of acetyl-CoA provision by 3-BrP normalised activity of diabetic platelets.
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Zhu X, Long D, Zabalawi M, Ingram B, Yoza BK, Stacpoole PW, McCall CE. Stimulating pyruvate dehydrogenase complex reduces itaconate levels and enhances TCA cycle anabolic bioenergetics in acutely inflamed monocytes. J Leukoc Biol 2020; 107:467-484. [PMID: 31894617 DOI: 10.1002/jlb.3a1119-236r] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 07/10/2019] [Revised: 11/24/2019] [Accepted: 12/11/2019] [Indexed: 02/06/2023] Open
Abstract
The pyruvate dehydrogenase complex (PDC)/pyruvate dehydrogenase kinase (PDK) axis directs the universal survival principles of immune resistance and tolerance in monocytes by controlling anabolic and catabolic energetics. Immune resistance shifts to immune tolerance during inflammatory shock syndromes when inactivation of PDC by increased PDK activity disrupts the tricarboxylic acid (TCA) cycle support of anabolic pathways. The transition from immune resistance to tolerance also diverts the TCA cycle from citrate-derived cis-aconitate to itaconate, a recently discovered catabolic mediator that separates the TCA cycle at isocitrate and succinate dehydrogenase (SDH). Itaconate inhibits succinate dehydrogenase and its anabolic role in mitochondrial ATP generation. We previously reported that inhibiting PDK in septic mice with dichloroacetate (DCA) increased TCA cycle activity, reversed septic shock, restored innate and adaptive immune and organ function, and increased survival. Here, using unbiased metabolomics in a monocyte culture model of severe acute inflammation that simulates sepsis reprogramming, we show that DCA-induced activation of PDC restored anabolic energetics in inflammatory monocytes while increasing TCA cycle intermediates, decreasing itaconate, and increasing amino acid anaplerotic catabolism of branched-chain amino acids (BCAAs). Our study provides new mechanistic insight that the DCA-stimulated PDC homeostat reconfigures the TCA cycle and promotes anabolic energetics in monocytes by reducing levels of the catabolic mediator itaconate. It further supports the theory that PDC is an energy sensing and signaling homeostat that restores metabolic and energy fitness during acute inflammation.
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Affiliation(s)
- Xuewei Zhu
- Department of Internal Medicine/Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.,Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - David Long
- Department of Internal Medicine/Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Manal Zabalawi
- Department of Internal Medicine/Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Brian Ingram
- Metabolon, Inc., Morrisville, North Carolina, USA
| | - Barbara K Yoza
- Department of Surgery/General Surgery and Trauma, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Peter W Stacpoole
- Division of Endocrinology, Diabetes & Metabolism, and Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Charles E McCall
- Department of Internal Medicine/Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.,Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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Bohne VJB, Bohne Ø. Suggested pathology of systemic exertion intolerance disease: Impairment of the E 3 subunit or crossover of swinging arms of the E 2 subunit of the pyruvate dehydrogenase complex decreases regeneration of cofactor dihydrolipoic acid of the E 2 subunit. Med Hypotheses 2019; 130:109260. [PMID: 31383326 DOI: 10.1016/j.mehy.2019.109260] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/22/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
Abstract
Systemic Exertion Intolerance Disease (SEID) or myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) has an unknown aetiology, with no known treatment and a prevalence of approximately 22 million individuals (2%) in Western countries. Although strongly suspected, the role of lactate in pathology is unknown, nor has the nature of the two most central symptoms of the condition - post exertional malaise and fatigue. The proposed mechanism of action of pyruvate dehydrogenase complex (PDC) plays a central role in maintaining energy production with cofactors alpha-lipoic acid (LA) and its counterpart dihydrolipoic acid (DHLA), its regeneration suggested as the new rate limiting factor. Decreased DHLA regeneration due to impairment of the E3 subunit or crossover of the swinging arms of the E2 subunit of PDC have been suggested as a cause of ME/CFS/SEID resulting in instantaneous fluctuations in lactate levels and instantaneous offset of the DHLA/LA ratio and defining the condition as an LA deficiency with chronic instantaneous hyperlactataemia with explicit stratification of symptoms. While instantaneous hyperlactataemia has been suggested to account for the PEM, the fatigue was explained by the downregulated throughput of pyruvate and consequently lower production of ATP with the residual enzymatic efficacy of the E3 subunit or crossover of the E2 as a proposed explanation of the fatigue severity. Functional diagnostics and visualization of instantaneous elevations of lactate and DHLA has been suggested. Novel treatment strategies have been implicated to compensate for chronic PDC impairment and hyperlactataemia. This hypothesis potentially influences the current understanding and treatment methods for any type of hyperlactataemia, fatigue, ME/CFS/SEID, and conditions associated with PDC impairment.
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Ambrus A. An Updated View on the Molecular Pathomechanisms of Human Dihydrolipoamide Dehydrogenase Deficiency in Light of Novel Crystallographic Evidence. Neurochem Res 2019; 44:2307-2313. [PMID: 30847858 PMCID: PMC6776566 DOI: 10.1007/s11064-019-02766-9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/22/2022]
Abstract
Dihydrolipoamide dehydrogenase (LADH, E3) deficiency is a rare (autosomal, recessive) genetic disorder generally presenting with an onset in the neonatal age and early death; the highest carrier rate has been found among Ashkenazi Jews. Acute clinical episodes usually involve severe metabolic decompensation and lactate acidosis that result in neurological, cardiological, and/or hepatological manifestations. Clinical severity is due to the fact that LADH is a common E3 subunit to the alpha-ketoglutarate, pyruvate, alpha-ketoadipate, and branched-chain alpha-keto acid dehydrogenase complexes, and is also a constituent in the glycine cleavage system, thus a loss in LADH function adversely affects multiple key metabolic routes. However, the severe clinical pictures frequently still do not parallel the LADH activity loss, which implies the involvement of auxiliary biochemical mechanisms; enhanced reactive oxygen species generation as well as affinity loss for multienzyme complexes proved to be key auxiliary exacerbating pathomechanisms. This review provides an overview and an up-to-date molecular insight into the pathomechanisms of this disease in light of the structural conclusions drawn from the first crystal structure of a disease-causing hE3 variant determined recently in our laboratory.
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Affiliation(s)
- Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary.
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Wang X, Wang A, Zhu L, Hua D, Qin J. Altering the sensitivity of Escherichia coli pyruvate dehydrogenase complex to NADH inhibition by structure-guided design. Enzyme Microb Technol 2018; 119:52-7. [PMID: 30243387 DOI: 10.1016/j.enzmictec.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/20/2018] [Accepted: 09/03/2018] [Indexed: 11/22/2022]
Abstract
A sufficient supply of reducing equivalents is essential for obtaining the maximum yield of target products in anaerobic fermentation. The pyruvate dehydrogenase (PDH) complex controls the critical step in pyruvate conversion to acetyl-CoA and NADH. However, in anaerobic Escherichia coli, PDH residing in the dihydrolipoamide dehydrogenase (LPD) component is normally inactive due to inhibition by NADH. In this study, the protein engineering of LPD by structural analysis was explored to eliminate this inhibition. A novel IAA350/351/358VVV triple mutant was successfully verified to be more effective than other LPD mutants reported till date. Notably, PDH activity with the triple mutant at an [NADH]/[NAD+] ratio of 0.15 was still higher than that of the wild-type without NADH addition. The altered enzyme of the PDH complex was also active in the presence of such high NADH levels. This is the first study concerning protein engineering of PDH by structure-guided design. The presence and functional activity of such an NADH-insensitive PDH complex provides a useful metabolic element for fermentation products and has potential for biotechnological application.
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16
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Szabo E, Mizsei R, Wilk P, Zambo Z, Torocsik B, Weiss MS, Adam-Vizi V, Ambrus A. Crystal structures of the disease-causing D444V mutant and the relevant wild type human dihydrolipoamide dehydrogenase. Free Radic Biol Med 2018; 124:214-220. [PMID: 29908278 DOI: 10.1016/j.freeradbiomed.2018.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 01/29/2023]
Abstract
We report the crystal structures of the human (dihydro)lipoamide dehydrogenase (hLADH, hE3) and its disease-causing homodimer interface mutant D444V-hE3 at 2.27 and 1.84 Å resolution, respectively. The wild type structure is a unique uncomplexed, unliganded hE3 structure with the true canonical sequence. Based on the structural information a novel molecular pathomechanism is proposed for the impaired catalytic activity and enhanced capacity for reactive oxygen species generation of the pathogenic mutant. The mechanistic model involves a previously much ignored solvent accessible channel leading to the active site that might be perturbed also by other disease-causing homodimer interface substitutions of this enzyme.
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Affiliation(s)
- Eszter Szabo
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary
| | - Reka Mizsei
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary
| | - Piotr Wilk
- Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany
| | - Zsofia Zambo
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary
| | - Beata Torocsik
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary
| | - Manfred S Weiss
- Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary
| | - Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, H-1094 Budapest, Hungary.
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Ferriero R, Nusco E, De Cegli R, Carissimo A, Manco G, Brunetti-Pierri N. Pyruvate dehydrogenase complex and lactate dehydrogenase are targets for therapy of acute liver failure. J Hepatol 2018; 69:325-335. [PMID: 29580866 PMCID: PMC6057136 DOI: 10.1016/j.jhep.2018.03.016] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/07/2018] [Accepted: 03/10/2018] [Indexed: 01/31/2023]
Abstract
BACKGROUND & AIMS Acute liver failure is a rapidly progressive deterioration of hepatic function resulting in high mortality and morbidity. Metabolic enzymes can translocate to the nucleus to regulate histone acetylation and gene expression. METHODS Levels and activities of pyruvate dehydrogenase complex (PDHC) and lactate dehydrogenase (LDH) were evaluated in nuclear fractions of livers of mice exposed to various hepatotoxins including CD95-antibody, α-amanitin, and acetaminophen. Whole-genome gene expression profiling by RNA-seq was performed in livers of mice with acute liver failure and analyzed by gene ontology enrichment analysis. Cell viability was evaluated in cell lines knocked-down for PDHA1 or LDH-A and in cells incubated with the LDH inhibitor galloflavin after treatment with CD95-antibody. We evaluated whether the histone acetyltransferase inhibitor garcinol or galloflavin could reduce liver damage in mice with acute liver failure. RESULTS Levels and activities of PDHC and LDH were increased in nuclear fractions of livers of mice with acute liver failure. The increase of nuclear PDHC and LDH was associated with increased concentrations of acetyl-CoA and lactate in nuclear fractions, and histone H3 hyper-acetylation. Gene expression in livers of mice with acute liver failure suggested that increased histone H3 acetylation induces the expression of genes related to damage response. Reduced histone acetylation by the histone acetyltransferase inhibitor garcinol decreased liver damage and improved survival in mice with acute liver failure. Knock-down of PDHC or LDH improved viability in cells exposed to a pro-apoptotic stimulus. Treatment with the LDH inhibitor galloflavin that was also found to inhibit PDHC, reduced hepatic necrosis, apoptosis, and expression of pro-inflammatory cytokines in mice with acute liver failure. Mice treated with galloflavin also showed a dose-response increase in survival. CONCLUSION PDHC and LDH translocate to the nucleus, leading to increased nuclear concentrations of acetyl-CoA and lactate. This results in histone H3 hyper-acetylation and expression of damage response genes. Inhibition of PDHC and LDH reduces liver damage and improves survival in mice with acute liver failure. Thus, PDHC and LDH are targets for therapy of acute liver failure. LAY SUMMARY Acute liver failure is a rapidly progressive deterioration of liver function resulting in high mortality. In experimental mouse models of acute liver failure, we found that two metabolic enzymes, namely pyruvate dehydrogenase complex and lactic dehydrogenase, translocate to the nucleus resulting in detrimental gene expression. Treatment with an inhibitor of these two enzymes was found to reduce liver damage and to improve survival.
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Affiliation(s)
- Rosa Ferriero
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Edoardo Nusco
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Annamaria Carissimo
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy,Institute for Applied Mathematics 'Mauro Picone', National Research Council, Naples, Italy
| | - Giuseppe Manco
- Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Translational Medicine, Federico II University of Naples, Naples, Italy.
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18
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Stacpoole PW, Shuster J, Thompson JLPS, Prather RA, Lawson LA, Zou B, Buchsbaum R, Nixon SJ. Development of a novel observer reported outcome tool as the primary efficacy outcome measure for a rare disease randomized controlled trial. Mitochondrion 2017; 42:59-63. [PMID: 29129554 DOI: 10.1016/j.mito.2017.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 06/02/2017] [Revised: 10/20/2017] [Accepted: 11/08/2017] [Indexed: 11/25/2022]
Abstract
We developed an Observer-Reported Outcome (ObsRO) survey instrument to be applied in a multicenter, placebo-controlled, crossover randomized controlled trial of dichloroacetate in children with pyruvate dehydrogenase complex deficiency. The instrument quantifies a subject's at-home level of functionality, as reported by a parent/caregiver, who were instrumental in providing the clinical descriptors and domains that formed the instrument's content. Feasibility testing of the ObsRO tool showed it to be easy to use and comprehensive in capturing the major clinical functional limitations of affected children and requires less than 5min for a parent/caregiver to complete daily.
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Affiliation(s)
- Peter W Stacpoole
- Department of Medicine (Division of Endocrinology, Diabetes and Metabolism) and Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, FL 32610, United States.
| | - Jonathan Shuster
- Department of Health Outcomes and Policy, University of Florida, College of Medicine, Gainesville, FL 32610, United States
| | - John L P Seamus Thompson
- Department of Biostatistics and Neurology, Mailman School of Public Health, Columbia University, New York, NY 10032, United States
| | - Robert A Prather
- Department of Psychiatry (Division of Addiction Research) and Biobehavioral Core, University of Florida, College of Medicine, Gainesville, FL 32610, United States
| | - Lee Ann Lawson
- Department of Medicine (Division of Endocrinology, Diabetes and Metabolism), University of Florida, College of Medicine, Gainesville, FL, United States
| | - Baiming Zou
- Department of Biostatistics, University of Florida, College of Medicine, Gainesville, FL 32610, United States
| | - Richard Buchsbaum
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, United States
| | - Sara Jo Nixon
- Department of Psychiatry (Division of Addiction Research) and Biobehavioral Core, University of Florida, College of Medicine, Gainesville, FL 32610, United States
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Fang A, Luo H, Liu L, Fan H, Zhou Y, Yao Y, Zhang Y. Identification of pyruvate dehydrogenase kinase 1 inhibitors with anti-osteosarcoma activity. Bioorg Med Chem Lett 2017; 27:5450-5453. [PMID: 29150396 DOI: 10.1016/j.bmcl.2017.10.073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 10/05/2017] [Revised: 10/25/2017] [Accepted: 10/28/2017] [Indexed: 02/05/2023]
Abstract
Overexpression of pyruvate dehydrogenase kinases (PDKs), especially PDK1 has been observed in a variety of cancers. Thus, targeting PDK1 offers an attractive opportunity for the development of cancer therapies. In this letter, we reported the identification of two novel PDK1 inhibitors as anti-osteosarcoma agents. We found that TM-1 and TM-2 inhibited PDK1 with the IC50 values of 2.97 and 3.41 μM, respectively. Furthermore, TM-1 and TM-2 dose-dependently reduced phosphorylation of pyruvate dehydrogenase complex in MG-63 osteosarcoma cells. Finally, TM-1 and TM-2 were found to inhibit the proliferation of MG-63 cells with the EC50 values of 14.5, and 11.0 μM, respectively, meaning TM-1 and TM-2 could be promising leads for the discovery of potent PDK1 inhibitors.
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Affiliation(s)
- Aiping Fang
- West China School of Public Health/No. 4 West China Teaching Hospital, Sichuan University, Chengdu 610041, PR China; State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Huiqiang Luo
- West China School of Public Health/No. 4 West China Teaching Hospital, Sichuan University, Chengdu 610041, PR China
| | - Liping Liu
- Department of Hepatobiliary and Pancreas Surgery, The Second Clinical Medical College of Jinan University, (Shenzhen People's Hospital), Shenzhen 518020, Guangdong Province, PR China
| | - Haibo Fan
- Department of Hepatobiliary and Pancreas Surgery, The Second Clinical Medical College of Jinan University, (Shenzhen People's Hospital), Shenzhen 518020, Guangdong Province, PR China
| | - Yaying Zhou
- Department of Hepatobiliary and Pancreas Surgery, The Second Clinical Medical College of Jinan University, (Shenzhen People's Hospital), Shenzhen 518020, Guangdong Province, PR China
| | - Yuqin Yao
- West China School of Public Health/No. 4 West China Teaching Hospital, Sichuan University, Chengdu 610041, PR China; State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Yue Zhang
- Department of Hepatobiliary and Pancreas Surgery, The Second Clinical Medical College of Jinan University, (Shenzhen People's Hospital), Shenzhen 518020, Guangdong Province, PR China.
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Ambrus A, Adam-Vizi V. Human dihydrolipoamide dehydrogenase (E3) deficiency: Novel insights into the structural basis and molecular pathomechanism. Neurochem Int 2017; 117:5-14. [PMID: 28579060 DOI: 10.1016/j.neuint.2017.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [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: 02/20/2017] [Revised: 05/22/2017] [Accepted: 05/30/2017] [Indexed: 11/18/2022]
Abstract
This review summarizes our present view on the molecular pathogenesis of human (h) E3-deficiency caused by a variety of genetic alterations with a special emphasis on the moonlighting biochemical phenomena related to the affected (dihydro)lipoamide dehydrogenase (LADH, E3, gene: dld), in particular the generation of reactive oxygen species (ROS). E3-deficiency is a rare autosomal recessive genetic disorder frequently presenting with a neonatal onset and premature death; the highest carrier rate of a single pathogenic dld mutation (1:94-1:110) was found among Ashkenazi Jews. Patients usually die during acute episodes that generally involve severe metabolic decompensation and lactic acidosis leading to neurological, cardiological, and/or hepatological manifestations. The disease owes its severity to the fact that LADH is the common E3 subunit of the alpha-ketoglutarate (KGDHc), pyruvate (PDHc), and branched-chain α-keto acid dehydrogenase complexes and is also part of the glycine cleavage system, hence the malfunctioning of LADH simultaneously incapacitates several central metabolic pathways. Nevertheless, the clinical pictures are usually not unequivocally portrayed through the loss of LADH activities and imply auxiliary mechanisms that exacerbate the symptoms and outcomes of this disorder. Enhanced ROS generation by disease-causing hE3 variants as well as by the E1-E2 subcomplex of the hKGDHc likely contributes to selected pathogeneses of E3-deficiency, which could be targeted by specific drugs or antioxidants; lipoic acid was demonstrated to be a potent inhibitor of ROS generation by hE3 in vitro. Flavin supplementation might prove to be beneficial for those mutations triggering FAD loss in the hE3 component. Selected pathogenic hE3 variants lose their affinity for the E2 component of the hPDHc, a mechanism which warrants scrutiny also for other E3-haboring complexes.
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Affiliation(s)
- Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, Hungary.
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, Hungary.
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Lecarpentier Y, Claes V, Vallée A, Hébert JL. Thermodynamics in cancers: opposing interactions between PPAR gamma and the canonical WNT/beta-catenin pathway. Clin Transl Med 2017; 6:14. [PMID: 28405929 DOI: 10.1186/s40169-017-0144-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/20/2017] [Indexed: 01/03/2023] Open
Abstract
Cancer cells are the site of numerous metabolic and thermodynamic abnormalities. We focus this review on the interactions between the canonical WNT/beta-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR gamma) in cancers and their implications from an energetic and metabolic point of view. In numerous tissues, PPAR gamma activation induces inhibition of beta-catenin pathway, while the activation of the canonical WNT/beta-catenin pathway inactivates PPAR gamma. In most cancers but not all, PPAR gamma is downregulated while the WNT/beta-catenin pathway is upregulated. In cancer cells, upregulation of the WNT/beta-catenin signaling induces dramatic changes in key metabolic enzymes that modify their thermodynamic behavior. This leads to activation of pyruvate dehydrogenase kinase1 (PDK-1) and monocarboxylate lactate transporter. Consequently, phosphorylation of PDK-1 inhibits the pyruvate dehydrogenase complex (PDH). Thus, a large part of pyruvate cannot be converted into acetyl-coenzyme A (acetyl-CoA) in mitochondria and only a part of acetyl-CoA can enter the tricarboxylic acid cycle. This leads to aerobic glycolysis in spite of the availability of oxygen. This phenomenon is referred to as the Warburg effect. Cytoplasmic pyruvate is converted into lactate. The WNT/beta-catenin pathway induces the transcription of genes involved in cell proliferation, i.e., MYC and CYCLIN D1. This ultimately promotes the nucleotide, protein and lipid synthesis necessary for cell growth and multiplication. In cancer, activation of the PI3K-AKT pathway induces an increase of the aerobic glycolysis. Moreover, prostaglandin E2 by activating the canonical WNT pathway plays also a role in cancer. In addition in many cancer cells, PPAR gamma is downregulated. Moreover, PPAR gamma contributes to regulate some key circadian genes. In cancers, abnormalities in the regulation of circadian rhythms (CRs) are observed. CRs are dissipative structures which play a key-role in far-from-equilibrium thermodynamics. In cancers, metabolism, thermodynamics and CRs are intimately interrelated.
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Abstract
The family of 2-oxoacid dehydrogenase complexes (2-OADC), typified by the pyruvate dehydrogenase multi-enzyme complex (PDC) as its most prominent member, are massive molecular machines (Mr, 4-10 million) controlling key steps in glucose homeostasis (PDC), citric acid cycle flux (OGDC, 2-oxoglutarate dehydrogenase) and the metabolism of the branched-chain amino acids, leucine, isoleucine and valine (BCOADC, branched-chain 2-OADC). These highly organised mitochondrial arrays, composed of multiple copies of three separate enzymes, have been widely studied as paradigms for the analysis of enzyme cooperativity, substrate channelling, protein-protein interactions and the regulation of activity by phosphorylation . This chapter will highlight recent advances in our understanding of the structure-function relationships, the overall organisation and the transport and assembly of PDC in particular, focussing on both native and recombinant forms of the complex and their individual components or constituent domains. Biophysical approaches, including X-ray crystallography (MX), nuclear magnetic resonance spectroscopy (NMR), cryo-EM imaging, analytical ultracentrifugation (AUC) and small angle X-ray and neutron scattering (SAXS and SANS), have all contributed significant new information on PDC subunit organisation, stoichiometry, regulatory mechanisms and mode of assembly. Moreover, the recognition of specific genetic defects linked to PDC deficiency, in combination with the ability to analyse recombinant PDCs housing both novel naturally-occurring and engineered mutations, have all stimulated renewed interest in these classical metabolic assemblies. In addition, the role played by PDC, and its constituent proteins, in certain disease states will be briefly reviewed, focussing on the development of new and exciting areas of medical and immunological research.
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Affiliation(s)
- Olwyn Byron
- School of Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - John Gordon Lindsay
- Institute of Molecular, Cell and Systems Biology, Davidson Building, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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Maeda S, Shimizu K, Kihira C, Iwabu Y, Kato R, Sugimoto M, Fukiya S, Wada M, Yokota A. Pyruvate dehydrogenase complex regulator (PdhR) gene deletion boosts glucose metabolism in Escherichia coli under oxygen-limited culture conditions. J Biosci Bioeng 2016; 123:437-443. [PMID: 28007420 DOI: 10.1016/j.jbiosc.2016.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/11/2016] [Indexed: 10/20/2022]
Abstract
Pyruvate dehydrogenase complex regulator (PdhR) is a transcriptional regulator that negatively regulates formation of pyruvate dehydrogenase complex (PDHc), NADH dehydrogenase (NDH)-2, and cytochrome bo3 oxidase in Escherichia coli. To investigate the effects of a PdhR defect on glucose metabolism, a pdhR deletion mutant was derived from the wild-type E. coli W1485 strain by λ Red-mediated recombination. While no difference in the fermentation profiles was observed between the two strains under oxygen-sufficient conditions, under oxygen-limited conditions, the growth level of the wild-type strain was significantly decreased with retarded glucose consumption accompanied by by-production of substantial amounts of pyruvic acid and acetic acid. In contrast, the mutant grew and consumed glucose more efficiently than did the wild-type strain with enhanced respiration, little by-production of pyruvic acid, less production yield and rates of acetic acid, thus displaying robust metabolic activity. As expected, increased activities of PDHc and NDH-2 were observed in the mutant. The increased activity of PDHc may explain the loss of pyruvic acid by-production, probably leading to decreased acetic acid formation, and the increased activity of NDH-2 may explain the enhanced respiration. Measurement of the intracellular NAD+/NADH ratio in the mutant revealed more oxidative or more reductive intracellular environments than those in the wild-type strain under oxygen-sufficient and -limited conditions, respectively, suggesting another role of PdhR: maintaining redox balance in E. coli. The overall results demonstrate the biotechnological advantages of pdhR deletion in boosting glucose metabolism and also improve our understanding of the role of PdhR in bacterial physiology.
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Affiliation(s)
- Soya Maeda
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Kumiko Shimizu
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Chie Kihira
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Yuki Iwabu
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Ryuichi Kato
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Makoto Sugimoto
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Satoru Fukiya
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Masaru Wada
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| | - Atsushi Yokota
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
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Zhou J, Wang D, Wang C, Gu J, Kim CH, Shi J, Jiang B, Wang M, Hao J. The Role of the Pyruvate Acetyl-CoA Switch in the Production of 1,3-Propanediol by Klebsiella pneumoniae. Appl Biochem Biotechnol 2017; 181:1199-210. [PMID: 27734285 DOI: 10.1007/s12010-016-2278-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 10/04/2016] [Indexed: 10/20/2022]
Abstract
Pyruvate dehydrogenase-complex (AcoABCD) and pyruvate formate-lyase (PFL) are two pathways responsible for synthesis of acetyl-CoA from pyruvate (pyruvate acetyl-CoA switch). The two pathways were individually deleted in Klebsiella pneumoniae, and the role of the pyruvate acetyl-CoA switch in 1,3-propanediol production was investigated. Fermentation results showed that the two pathways were both active in the wild-type strain. Acetyl-CoA formation between the two pathways was equal in the wild-type strain. The pflB mutant produced high level of lactic acid, and deletion of ldhA eliminated lactic acid synthesis. The conversion ratio of glycerol to 1,3-propanediol in the pflB-ldhA mutant reached 0.541 g/g, which was 9.4 % higher than that of the wild-type strain. However, the productivity of 1,3-propanediol was decreased in the pflB-ldhA mutant. In contrast, the productivity of 1,3-propanediol was increased by 19 % in the acoABCD mutant, with the disadvantage of lower substrate conversion ratio. Regulating the pyruvate acetyl-CoA switch presents a novel way to improve the conversion ratio or productivity of 1,3-propanediol produced by K. pneumoniae.
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Perez-Siles G, Ly C, Grant A, Drew AP, Yiu EM, Ryan MM, Chuang DT, Tso SC, Nicholson GA, Kennerson ML. Pathogenic mechanisms underlying X-linked Charcot-Marie-Tooth neuropathy (CMTX6) in patients with a pyruvate dehydrogenase kinase 3 mutation. Neurobiol Dis 2016; 94:237-44. [PMID: 27388934 DOI: 10.1016/j.nbd.2016.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/22/2016] [Accepted: 07/03/2016] [Indexed: 10/21/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy. An X-linked form of CMT (CMTX6) is caused by a missense mutation (R158H) in the pyruvate dehydrogenase kinase isoenzyme 3 (PDK3) gene. PDK3 is one of 4 isoenzymes that negatively regulate the activity of the pyruvate dehydrogenase complex (PDC) by reversible phosphorylation of its first catalytic component pyruvate dehydrogenase (designated as E1). Mitochondrial PDC catalyses the oxidative decarboxylation of pyruvate to acetyl CoA and links glycolysis to the energy-producing Krebs cycle. We have previously shown the R158H mutation confers PDK3 enzyme hyperactivity. In this study we demonstrate that the increased PDK3 activity in patient fibroblasts (PDK3(R158H)) leads to the attenuation of PDC through hyper-phosphorylation of E1 at selected serine residues. This hyper-phosphorylation can be reversed by treating the PDK3(R158H) fibroblasts with the PDK inhibitor dichloroacetate (DCA). In the patient cells, down-regulation of PDC leads to increased lactate, decreased ATP and alteration of the mitochondrial network. Our findings highlight the potential to develop specific drug targeting of the mutant PDK3 as a therapeutic approach to treating CMTX6.
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Affiliation(s)
- Gonzalo Perez-Siles
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
| | - Carolyn Ly
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia
| | - Adrienne Grant
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia
| | - Alexander P Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia
| | - Eppie M Yiu
- Department of Neurology, Royal Children's Hospital, Flemington Road, Parkville, VIC, Australia; Neuroscience Research, Murdoch Childrens Research Institute, Melbourne, VIC, Australia; Department of Pediatrics, The University of Melbourne, VIC, Australia
| | - Monique M Ryan
- Department of Neurology, Royal Children's Hospital, Flemington Road, Parkville, VIC, Australia; Neuroscience Research, Murdoch Childrens Research Institute, Melbourne, VIC, Australia; Department of Pediatrics, The University of Melbourne, VIC, Australia
| | - David T Chuang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shih-Chia Tso
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Garth A Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia; Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Concord, NSW, Australia; Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
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Battello N, Zimmer AD, Goebel C, Dong X, Behrmann I, Haan C, Hiller K, Wegner A. The role of HIF-1 in oncostatin M-dependent metabolic reprogramming of hepatic cells. Cancer Metab 2016; 4:3. [PMID: 26889381 PMCID: PMC4756539 DOI: 10.1186/s40170-016-0141-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/17/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Hypoxia and inflammation have been identified as hallmarks of cancer. A majority of hepatocellular carcinomas are preceded by hepatitis B- or C-related chronic infections suggesting that liver cancer development is promoted by an inflammatory microenvironment. The inflammatory cytokine oncostatin M (OSM) was shown to induce the expression of hypoxia-inducible factor-1 α (HIF-1 α) under normoxic conditions in hepatocytes and hepatoma cells. HIF-1 α is known to orchestrate the expression of numerous genes, many of which code for metabolic enzymes that play key roles in the adaptation of cellular metabolism to low oxygen tension. RESULTS Here, we show that OSM-induced upregulation of HIF-1 α reprograms cellular metabolism in three clones of the human hepatocyte cell line PH5CH (PH5CH1, PH5CH7, and PH5CH8) towards a hypoxia-like metabolic phenotype but has no significant effect on cellular metabolism of HepG2 and JHH-4 hepatoma cells. Although we observed only minor changes in glucose uptake and lactate secretion in PH5CH8 upon OSM treatment, we identified more pronounced changes in intracellular fluxes based on stable isotope labeling experiments. In particular, glucose oxidation in the tricarboxylic acid (TCA) cycle is reduced through pyruvate dehydrogenase kinase 1 (PDK1)-mediated inhibition of the pyruvate dehydrogenase complex, thereby reducing the oxidative TCA cycle flux. As a result of the impaired mitochondrial glucose and glutamine oxidation, the reductive isocitrate dehydrogenase flux was increased. CONCLUSIONS We provide evidence that connects the inflammatory mediator OSM to a hypoxia-like metabolic phenotype. In the human hepatocyte cell line PH5CH, OSM-mediated upregulation of HIF-1 α and PDK1 can induce hypoxia-like metabolic changes, although to a lesser extent than hypoxia itself. Since PDK1 is overexpressed in several cancers, it might provide a causal link between chronic inflammation and malignant cellular transformation.
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Affiliation(s)
- Nadia Battello
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Avenue des Hauts-Fourneaux 7, Esch-Belval, L-4362 Luxembourg
| | - Andreas David Zimmer
- Life Sciences Research Unit, University of Luxembourg, Avenue de la Fäincerie 162a, Luxembourg, 1511 Luxembourg
| | - Carole Goebel
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Avenue des Hauts-Fourneaux 7, Esch-Belval, L-4362 Luxembourg
| | - Xiangyi Dong
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Avenue des Hauts-Fourneaux 7, Esch-Belval, L-4362 Luxembourg
| | - Iris Behrmann
- Life Sciences Research Unit, University of Luxembourg, Avenue de la Fäincerie 162a, Luxembourg, 1511 Luxembourg
| | - Claude Haan
- Life Sciences Research Unit, University of Luxembourg, Avenue de la Fäincerie 162a, Luxembourg, 1511 Luxembourg
| | - Karsten Hiller
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Avenue des Hauts-Fourneaux 7, Esch-Belval, L-4362 Luxembourg
| | - Andre Wegner
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Avenue des Hauts-Fourneaux 7, Esch-Belval, L-4362 Luxembourg
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27
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Ambrus A, Nemeria NS, Torocsik B, Tretter L, Nilsson M, Jordan F, Adam-Vizi V. Formation of reactive oxygen species by human and bacterial pyruvate and 2-oxoglutarate dehydrogenase multienzyme complexes reconstituted from recombinant components. Free Radic Biol Med 2015; 89:642-50. [PMID: 26456061 PMCID: PMC4684775 DOI: 10.1016/j.freeradbiomed.2015.10.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 09/18/2015] [Accepted: 10/03/2015] [Indexed: 01/25/2023]
Abstract
Individual recombinant components of pyruvate and 2-oxoglutarate dehydrogenase multienzyme complexes (PDHc, OGDHc) of human and Escherichia coli (E. coli) origin were expressed and purified from E. coli with optimized protocols. The four multienzyme complexes were each reconstituted under optimal conditions at different stoichiometric ratios. Binding stoichiometries for the highest catalytic efficiency were determined from the rate of NADH generation by the complexes at physiological pH. Since some of these complexes were shown to possess 'moonlighting' activities under pathological conditions often accompanied by acidosis, activities were also determined at pH 6.3. As reactive oxygen species (ROS) generation by the E3 component of hOGDHc is a pathologically relevant feature, superoxide generation by the complexes with optimal stoichiometry was measured by the acetylated cytochrome c reduction method in both the forward and the reverse catalytic directions. Various known affectors of physiological activity and ROS production, including Ca(2+), ADP, lipoylation status or pH, were investigated. The human complexes were also reconstituted with the most prevalent human pathological mutant of the E3 component, G194C and characterized; isolated human E3 with the G194C substitution was previously reported to have an enhanced ROS generating capacity. It is demonstrated that: i. PDHc, similarly to OGDHc, is able to generate ROS and this feature is displayed by both the E. coli and human complexes, ii. Reconstituted hPDHc generates ROS at a significantly higher rate as compared to hOGDHc in both the forward and the reverse reactions when ROS generation is calculated for unit mass of their common E3 component, iii. The E1 component or E1-E2 subcomplex generates significant amount of ROS only in hOGDHc; iv. Incorporation of the G194C variant of hE3, the result of a disease-causing mutation, into reconstituted hOGDHc and hPDHc indeed leads to a decreased activity of both complexes and higher ROS generation by only hOGDHc and only in its reverse reaction.
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Affiliation(s)
- Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Natalia S Nemeria
- Department of Chemistry, Rutgers, the State University, Newark, NJ 07102, USA
| | - Beata Torocsik
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Laszlo Tretter
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Mattias Nilsson
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Frank Jordan
- Department of Chemistry, Rutgers, the State University, Newark, NJ 07102, USA
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary.
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Abstract
Impaired glucose homeostasis is one of the risk factors for causing metabolic diseases including obesity, type 2 diabetes, and cancers. In glucose metabolism, pyruvate dehydrogenase complex (PDC) mediates a major regulatory step, an irreversible reaction of oxidative decarboxylation of pyruvate to acetyl-CoA. Tight control of PDC is critical because it plays a key role in glucose disposal. PDC activity is tightly regulated using phosphorylation by pyruvate dehydrogenase kinases (PDK1 to 4) and pyruvate dehydrogenase phosphatases (PDP1 and 2). PDKs and PDPs exhibit unique tissue expression patterns, kinetic properties, and sensitivities to regulatory molecules. During the last decades, the up-regulation of PDKs has been observed in the tissues of patients and mammals with metabolic diseases, which suggests that the inhibition of these kinases may have beneficial effects for treating metabolic diseases. This review summarizes the recent advances in the role of specific PDK isoenzymes on the induction of metabolic diseases and describes the effects of PDK inhibition on the prevention of metabolic diseases using pharmacological inhibitors. Based on these reports, PDK isoenzymes are strong therapeutic targets for preventing and treating metabolic diseases.
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Affiliation(s)
- Nam Ho Jeoung
- Department of Pharmaceutical Science and Technology, Catholic University of Daegu College of Medical Sciences, Gyeongsan, Korea
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29
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He JB, He HF, Zhao LL, Zhang L, You GY, Feng LL, Wan J, He HW. Synthesis and antifungal activity of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives as pyruvate dehydrogenase complex E1 inhibitors. Bioorg Med Chem 2015; 23:1395-401. [PMID: 25766628 DOI: 10.1016/j.bmc.2015.02.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [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: 12/22/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
Abstract
To identify new antifungal lead compound based on inhibitors of pyruvate dehydrogenase complex E1, a series of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives 3 were prepared and evaluated for their Escherichia coli PDHc-E1 inhibitory activity and antifungal activity. The in vitro bioassay for the PDHc-E1 inhibition indicated all the compounds exhibited significant inhibition against E. coli PDHc-E1 (IC50<21μM), special compound 3g showed the most potent inhibitory activity (IC50=4.21±0.11μM) and was demonstrated to act as a competitive inhibitor of PDHc-E1. Meanwhile, inhibitor 3g exhibited very good enzyme-selective inhibition of PDHc-E1 between pig heart and E. coli. The assay of antifungal activity showed compounds 3e, 3g, and 3n exhibited fair to good activity against Rhizoctonia solani and Botrytis cinerea even at 12.5μg/mL. Especially compound 3n (EC50=5.4μg/mL; EC90=21.1μg/mL) exhibited almost 5.50 times inhibitory potency against B. cinerea than that of pyrimethanil (EC50=29.6μg/mL; EC90=113.4μg/mL). Therefore, in this study, compound 3n was found to be a novel lead compound for further optimization to find more potent antifungal compounds as microbial PDHc-E1 inhibitors.
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Affiliation(s)
- Jun-Bo He
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China; College of Food Science & Engineering, Wuhan Polytechnic University, Wuhan 430023, China; Hubei Collaborative Innovation Center for Processing of Agricultural Products, Wuhan 430023, China
| | - Hai-Feng He
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Lu-Lu Zhao
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Li Zhang
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Ge-Yun You
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Ling-Ling Feng
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Jian Wan
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China.
| | - Hong-Wu He
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, Department of Chemistry, Central China Normal University, Wuhan 430079, China.
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30
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Igamberdiev AU, Lernmark U, Gardeström P. Activity of the mitochondrial pyruvate dehydrogenase complex in plants is stimulated in the presence of malate. Mitochondrion 2014; 19 Pt B:184-90. [PMID: 24747677 DOI: 10.1016/j.mito.2014.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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: 02/11/2014] [Revised: 03/31/2014] [Accepted: 04/04/2014] [Indexed: 11/20/2022]
Abstract
The effect of malate on the steady-state activity of the pea (Pisum sativum L.) and barley (Hordeum vulgare L.) leaf pyruvate dehydrogenase complex (PDC) has been studied in isolated mitochondria. The addition of malate was found to be stimulatory for the mitochondrial PDC, however there was no stimulation of chloroplast PDC. The stimulation was saturated below 1mM malate and was apparently related to а partially activated complex, which activity increased in the presence of malate by about twofold. Malate also reversed the reduction of PDC activity in the presence of glycine. Based on the obtained kinetic data, we suggest that the effect of malate is rather not a direct activation of PDC but involves the establishment of NAD-malate dehydrogenase equilibrium, decreasing concentration of NADH and relieving its inhibitory effect of PDC.
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Affiliation(s)
- Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
| | - Ulrikа Lernmark
- Umeå Plant Science Centre, Department of Plant Physiology, University of Umeå, SE-901 87 Umeå, Sweden
| | - Per Gardeström
- Umeå Plant Science Centre, Department of Plant Physiology, University of Umeå, SE-901 87 Umeå, Sweden.
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31
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Jordan F, Nemeria NS. Progress in the experimental observation of thiamin diphosphate-bound intermediates on enzymes and mechanistic information derived from these observations. Bioorg Chem 2014; 57:251-262. [PMID: 25228115 DOI: 10.1016/j.bioorg.2014.08.002] [Citation(s) in RCA: 18] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/11/2014] [Indexed: 11/26/2022]
Abstract
Thiamin diphosphate (ThDP), the vitamin B1 coenzyme is an excellent representative of coenzymes, which carry out electrophilic catalysis by forming a covalent complex with their substrates. The function of ThDP is to greatly increase the acidity of two carbon acids by stabilizing their conjugate bases, the ylide/carbene/C2-carbanion of the thiazolium ring and the C2α-carbanion/enamine, once the substrate binds to ThDP. In recent years, several ThDP-bound intermediates on such pathways have been characterized by both solution and solid-state methods. Prominent among these advances are X-ray crystallographic results identifying both oxidative and non-oxidative intermediates, rapid chemical quench followed by NMR detection of several intermediates which are stable under acidic conditions, solid-state NMR and circular dichroism detection of the states of ionization and tautomerization of the 4'-aminopyrimidine moiety of ThDP in some of the intermediates. These methods also enabled in some cases determination of the rate-limiting step in the complex series of steps. This review is an update of a review with the same title published by the authors in 2005 in this Journal. Much progress has been made in the intervening decade in the identification of the intermediates and their application to gain additional mechanistic insight.
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Affiliation(s)
- Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
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32
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Kankotia S, Stacpoole PW. Dichloroacetate and cancer: new home for an orphan drug? Biochim Biophys Acta Rev Cancer 2014; 1846:617-29. [PMID: 25157892 DOI: 10.1016/j.bbcan.2014.08.005] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [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: 06/13/2014] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 02/06/2023]
Abstract
We reviewed the anti-cancer effects of DCA, an orphan drug long used as an investigational treatment for various acquired and congenital disorders of mitochondrial intermediary metabolism. Inhibition by DCA of mitochondrial pyruvate dehydrogenase kinases and subsequent reactivation of the pyruvate dehydrogenase complex and oxidative phosphorylation is the common mechanism accounting for the drug's anti-neoplastic effects. At least two fundamental changes in tumor metabolism are induced by DCA that antagonize tumor growth, metastases and survival: the first is the redirection of glucose metabolism from glycolysis to oxidation (reversal of the Warburg effect), leading to inhibition of proliferation and induction of caspase-mediated apoptosis. These effects have been replicated in both human cancer cell lines and in tumor implants of diverse germ line origin. The second fundamental change is the oxidative removal of lactate, via pyruvate, and the co-incident buffering of hydrogen ions by dehydrogenases located in the mitochondrial matrix. Preclinical studies demonstrate that DCA has additive or synergistic effects when used in combination with standard agents designed to modify tumor oxidative stress, vascular remodeling, DNA integrity or immunity. These findings and limited clinical results suggest that potentially fruitful areas for additional clinical trials include 1) adult and pediatric high grade astrocytomas; 2) BRAF-mutant cancers, such as melanoma, perhaps combined with other pro-oxidants; 3) tumors in which resistance to standard platinum-class drugs alone may be overcome with combination therapy; and 4) tumors of endodermal origin, in which extensive experimental research has demonstrated significant anti-proliferative, pro-apoptotic effects of DCA, leading to improved host survival.
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Affiliation(s)
- Shyam Kankotia
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Florida College of Medicine, Gainesville, FL, United States
| | - Peter W Stacpoole
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Florida College of Medicine, Gainesville, FL, United States; Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, United States.
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33
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Kikuchi D, Minamishima YA, Nakayama K. Prolyl-hydroxylase PHD3 interacts with pyruvate dehydrogenase (PDH)-E1β and regulates the cellular PDH activity. Biochem Biophys Res Commun 2014; 451:288-94. [PMID: 25088999 DOI: 10.1016/j.bbrc.2014.07.114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 07/24/2014] [Indexed: 01/25/2023]
Abstract
Cells are frequently exposed to hypoxia in physiological and pathophysiological conditions in organisms. Control of energy metabolism is one of the critical functions of the hypoxic response. Hypoxia-Inducible Factor (HIF) is a central transcription factor that regulates the hypoxic response. HIF prolyl-hydroxylase PHDs are the enzymes that hydroxylate the α subunit of HIF and negatively regulate its expression. To further understand the physiological role of PHD3, proteomics were used to identify PHD3-interacting proteins, and pyruvate dehydrogenase (PDH)-E1β was identified as such a protein. PDH catalyzes the conversion of pyruvate to acetyl-coA, thus playing a key role in cellular energy metabolism. PDH activity was significantly decreased in PHD3-depleted MCF7 breast cancer cells and PHD3(-/-) MEFs. PHD3 depletion did not affect the expression of the PDH-E1α, E1β, and E2 subunits, or the phosphorylation status of E1α, but destabilized the PDH complex (PDC), resulting in less functional PDC. Finally, PHD3(-/-) cells were resistant to cell death in prolonged hypoxia with decreased production of ROS. Taken together, the study reveals that PHD3 regulates PDH activity in cells by physically interacting with PDC.
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Affiliation(s)
- Daisuke Kikuchi
- Oxygen Biology Laboratory, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yoji Andrew Minamishima
- Department of Biochemistry, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan; Japan Science and Technology Agency (JST), Exploratory Research for Advanced Technology (ERATO), Suematsu Gas Biology Project, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Koh Nakayama
- Oxygen Biology Laboratory, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan.
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Eikmanns BJ, Blombach B. The pyruvate dehydrogenase complex of Corynebacterium glutamicum: an attractive target for metabolic engineering. J Biotechnol 2014; 192 Pt B:339-45. [PMID: 24486441 DOI: 10.1016/j.jbiotec.2013.12.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [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: 11/04/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 11/18/2022]
Abstract
The pyruvate dehydrogenase complex (PDHC) catalyzes the oxidative thiamine pyrophosphate-dependent decarboxylation of pyruvate to acetyl-CoA and CO2. Since pyruvate is a key metabolite of the central metabolism and also the precursor for several relevant biotechnological products, metabolic engineering of this multienzyme complex is a promising strategy to improve microbial production processes. This review summarizes the current knowledge and achievements on metabolic engineering approaches to tailor the PDHC of Corynebacterium glutamicum for the bio-based production of l-valine, 2-ketosiovalerate, pyruvate, succinate and isobutanol and to improve l-lysine production.
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Affiliation(s)
- Bernhard J Eikmanns
- Institute of Microbiology and Biotechnology, University of Ulm, 89069 Ulm, Germany
| | - Bastian Blombach
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany.
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Fisher-Wellman KH, Gilliam LAA, Lin CT, Cathey BL, Lark DS, Darrell Neufer P. Mitochondrial glutathione depletion reveals a novel role for the pyruvate dehydrogenase complex as a key H2O2-emitting source under conditions of nutrient overload. Free Radic Biol Med 2013; 65:1201-1208. [PMID: 24056031 PMCID: PMC3965186 DOI: 10.1016/j.freeradbiomed.2013.09.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 08/26/2013] [Accepted: 09/13/2013] [Indexed: 11/25/2022]
Abstract
Once regarded as a "by-product" of aerobic metabolism, the production of superoxide/H2O2 is now understood to be a highly specialized and extensively regulated process responsible for exerting control over a vast number of thiol-containing proteins, collectively referred to as the redox-sensitive proteome. Although disruptions within this process, secondary to elevated peroxide exposure, have been linked to disease, the sources and mechanisms regulating increased peroxide burden remain poorly defined and as such are difficult to target using pharmacotherapy. Here we identify the pyruvate dehydrogenase complex (PDC) as a key source of H2O2 within skeletal muscle mitochondria under conditions of depressed glutathione redox buffering integrity. Treatment of permeabilized myofibers with varying concentrations of the glutathione-depleting agent 1-chloro-2,4-dinitrobenzene led to a dose-dependent increase in pyruvate-supported JH2O2 emission (the flux of H2O2 diffusing out of the mitochondrial matrix into the surrounding assay medium), with emission rates eventually rising to exceed those of all substrate combinations tested. This striking sensitivity to glutathione depletion was observed in permeabilized fibers prepared from multiple species and was specific to PDC. Physiological oxidation of the cellular glutathione pool after high-fat feeding in rodents was found to elevate PDC JH2O2 emission, as well as increasing the sensitivity of the complex to GSH depletion. These findings reveal PDC as a potential major site of H2O2 production that is extremely sensitive to mitochondrial glutathione redox status.
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Affiliation(s)
- Kelsey H Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Physiology, East Carolina University, Greenville, NC 27858, USA.
| | - Laura A A Gilliam
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Physiology, East Carolina University, Greenville, NC 27858, USA
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Physiology, East Carolina University, Greenville, NC 27858, USA
| | - Brook L Cathey
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Physiology, East Carolina University, Greenville, NC 27858, USA
| | - Daniel S Lark
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Kinesiology, East Carolina University, Greenville, NC 27858, USA
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA; Department of Physiology, East Carolina University, Greenville, NC 27858, USA; Department of Kinesiology, East Carolina University, Greenville, NC 27858, USA
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Holness MJ, Zariwala G, Walker CG, Sugden MC. Adipocyte pyruvate dehydrogenase kinase 4 expression is associated with augmented PPARγ upregulation in early-life programming of later obesity. FEBS Open Bio 2012; 2:32-6. [PMID: 23650578 DOI: 10.1016/j.fob.2012.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 01/08/2023] Open
Abstract
We studied adipocytes from 8-week-old control rat offspring (CON) or rat offspring subjected to maternal low (8%) protein (MLP) feeding during pregnancy/lactation, a procedure predisposing to obesity. Acute exposure to isoproterenol or adenosine enhanced PDK4 and PPARγ mRNA gene expression in CON and MLP adipocytes. Enhanced adipocyte Pdk4 expression correlated with increased PPARγ expression. Higher levels of PDK4 and PPARγ were observed in MLP adipocytes. SCD1 is a PPARγ target. Isoproterenol enhanced adipocyte PDK4 and SCD1 gene expression in parallel. This could reflect augmented PPARγ expression together with enhanced lipolytic stimulation to supply endogenous PPARγ ligands, allowing enhanced adipocyte PDK4 and SCD1 expression via PPARγ activation. In contrast, the effect of adenosine to increase PDK4 expression is independent of stimulation of lipolysis and, as SCD1 expression was unaffected by adenosine, unlikely to reflect PPARγ activation. Increased adipocyte expression of both PDK4 and SCD1 in the MLP model could participate as components of a "thrifty" phenotype, favouring the development of obesity.
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Key Words
- ADO, adenosine
- Adipose tissue
- BSA, bovine serum albumin
- CON, control
- HSL, hormone-sensitive lipase
- ISO, isoproterenol
- KRHB, Krebs–Ringer HEPES buffer
- Lipogenesis
- MLP, maternal low protein
- NEFA, non-esterified fatty acid
- PC, pyruvate carboxylase
- PDC, pyruvate dehydrogenase complex
- PDK, pyruvate dehydrogenase kinase
- PEPCK, phosphoenolpyruvate carboxykinase
- PPAR, peroxisome proliferator-activated receptor
- Programming
- Pyruvate dehydrogenase complex
- SCD, stearoyl-CoA desaturase
- TAG, triacylglycerol
- WAT, white adipose tissue
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Abstract
In the well-fed state a relatively high activity of the pyruvate dehydrogenase complex (PDC) reduces blood glucose levels by directing the carbon of pyruvate into the citric acid cycle. In the fasted state a relatively low activity of the PDC helps maintain blood glucose levels by conserving pyruvate and other three carbon compounds for gluconeogenesis. The relative activities of the pyruvate dehydrogenase kinases (PDKs) and the opposing pyruvate dehydrogenase phosphatases determine the activity of PDC in the fed and fasted states. Up regulation of PDK4 is largely responsible for inactivation of PDC in the fasted state. PDK4 knockout mice have lower fasting blood glucose levels than wild type mice, proving that up regulation of PDK4 is important for normal glucose homeostasis. In type 2 diabetes, up regulation of PDK4 also inactivates PDC, which promotes gluconeogenesis and thereby contributes to the hyperglycemia characteristic of this disease. When fed a high fat diet, wild type mice develop fasting hyperglycemia but PDK4 knockout mice remain euglycemic, proving that up regulation of PDK4 contributes to hyperglycemia in diabetes. These finding suggest PDK4 inhibitors might prove useful in the treatment of type 2 diabetes.
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Affiliation(s)
- Nam Ho Jeoung
- Department of Fundamental Medical and Pharmaceutical Sciences, Catholic University of Daegu, Gyeongsan, Korea
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Braun S, Berg C, Buck S, Gregor M, Klein R. Catalytic domain of PDC-E2 contains epitopes recognized by antimitochondrial antibodies in primary biliary cirrhosis. World J Gastroenterol 2010; 16:973-81. [PMID: 20180236 PMCID: PMC2828602 DOI: 10.3748/wjg.v16.i8.973] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To search for further immunodominant peptides of the pyruvate dehydrogenase complex E2-component (PDC-E2) recognized by antimitochondrial antibodies (AMA) in primary biliary cirrhosis (PBC).
METHODS: Sera from 95 patients with PBC were tested by enzyme-linked immunosorbent assay against 33 synthetic overlapping peptides (25 amino acids; aa) covering the entire length of the E2-subunit of PDC-E2. Furthermore, the inner lipoyl peptide 167-184 was used in an unlipoylated and a lipoylated form as well as coupled to ovalbumin. Sera from 11 AMA negative/ANA positive PBC patients, 63 patients with other liver disorders and 22 healthy blood donors served as controls.
RESULTS: Of the 95 PBC-sera, 74% reacted with the peptide 475-499 and 58% with the peptide 407-431 located within the catalytic domain of PDC-E2. Patients with other disorders or healthy controls were positive in only up to 18%. Antibodies to the unlipoylated and lipoylated peptide 167-184 within the inner lipoyl domain were found in only 5% and 11% of the PBC sera, respectively; using ovalbumin-coupled peptides, the incidence increased up to 57% (unlipoylated form).
CONCLUSION: Peptides within the catalytic site of PDC-E2 rather than the previously reported lipoyl binding peptide 167-184 may represent major immunodominant epitopes recognized by AMA in PBC.
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