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Mandal AA, Kushwaha R, Yadav AK, Banerjee S. Metal Complexes for Cancer Sonodynamic Therapy. Chembiochem 2023; 24:e202200597. [PMID: 36385722 DOI: 10.1002/cbic.202200597] [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: 10/18/2022] [Revised: 11/16/2022] [Accepted: 11/16/2022] [Indexed: 11/18/2022]
Abstract
Sonodynamic therapy (SDT) for cancer treatment is gaining attention owing to its non-invasive property and ultrasound's (US) deep tissue penetration ability. In SDT, US activates the sonosensitizer at the target deep-seated tumors to generate reactive oxygen species (ROS), which ultimately damage tumors. However, drawbacks such as insufficient ROS production, aggregation of sonosensitizer, off-target side effects, etc., of the current organic/nanomaterial-based sonosensitizers limit the effectiveness of cancer SDT. Very recently, metal complexes with tunable physiochemical properties (such as sonostability, HOMO to LUMO energy gap, ROS generation ability, aqueous solubility, emission, etc.) have been devised as effective sonosensitizers, which could overcome the limitations of organic/nanomaterial-based sonosensitizers. This concept introduces all the reported metal-based sonosensitizers and delineates the prospects of metal complexes in cancer sonodynamic therapy. This new concept of metal-based sonosensitizer can deliver next-generation cancer drugs.
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Gagné F, Houda H, André C. Altered mitochondria oscillations and circadian changes in NADH levels in freshwaters mussels exposed to cadmium. Comp Biochem Physiol C Toxicol Pharmacol 2022; 260:109420. [PMID: 35902061 DOI: 10.1016/j.cbpc.2022.109420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/27/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Affiliation(s)
- F Gagné
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada.
| | - H Houda
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada
| | - C André
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada
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Duarte M, Ferreira C, Khandpur GK, Flohr T, Zimmermann J, Castro H, Herrmann JM, Morgan B, Tomás AM. Leishmania type II dehydrogenase is essential for parasite viability irrespective of the presence of an active complex I. Proc Natl Acad Sci U S A 2021; 118:e2103803118. [PMID: 34654744 DOI: 10.1073/pnas.2103803118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2021] [Indexed: 11/18/2022] Open
Abstract
Type II NADH dehydrogenases (NDH2) are monotopic enzymes present in the external or internal face of the mitochondrial inner membrane that contribute to NADH/NAD+ balance by conveying electrons from NADH to ubiquinone without coupled proton translocation. Herein, we characterize the product of a gene present in all species of the human protozoan parasite Leishmania as a bona fide, matrix-oriented, type II NADH dehydrogenase. Within mitochondria, this respiratory activity concurs with that of type I NADH dehydrogenase (complex I) in some Leishmania species but not others. To query the significance of NDH2 in parasite physiology, we attempted its genetic disruption in two parasite species, exhibiting a silent (Leishmania infantum, Li) and a fully operational (Leishmania major, Lm) complex I. Strikingly, this analysis revealed that NDH2 abrogation is not tolerated by Leishmania, not even by complex I-expressing Lm species. Conversely, complex I is dispensable in both species, provided that NDH2 is sufficiently expressed. That a type II dehydrogenase is essential even in the presence of an active complex I places Leishmania NADH metabolism into an entirely unique perspective and suggests unexplored functions for NDH2 that span beyond its complex I-overlapping activities. Notably, by showing that the essential character of NDH2 extends to the disease-causing stage of Leishmania, we genetically validate NDH2-an enzyme without a counterpart in mammals-as a candidate target for leishmanicidal drugs.
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Lencina AM, Koepke J, Preu J, Muenke C, Gennis RB, Michel H, Schurig-Briccio LA. Characterization and X-ray structure of the NADH-dependent coenzyme A disulfide reductase from Thermus thermophilus. Biochim Biophys Acta Bioenerg 2019; 1860:148080. [PMID: 31520616 DOI: 10.1016/j.bbabio.2019.148080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/28/2019] [Accepted: 09/08/2019] [Indexed: 11/25/2022]
Abstract
The crystal structure of the enzyme previously characterized as a type-2 NADH:menaquinone oxidoreductase (NDH-2) from Thermus thermophilus has been solved at a resolution of 2.9 Å and revealed that this protein is, in fact, a coenzyme A-disulfide reductase (CoADR). Coenzyme A (CoASH) replaces glutathione as the major low molecular weight thiol in Thermus thermophilus and is maintained in the reduced state by this enzyme (CoADR). Although the enzyme does exhibit NADH:menadione oxidoreductase activity expected for NDH-2 enzymes, the specific activity with CoAD as an electron acceptor is about 5-fold higher than with menadione. Furthermore, the crystal structure contains coenzyme A covalently linked Cys44, a catalytic intermediate (Cys44-S-S-CoA) reduced by NADH via the FAD cofactor. Soaking the crystals with menadione shows that menadione can bind to a site near the redox active FAD, consistent with the observed NADH:menadione oxidoreductase activity. CoADRs from other species were also examined and shown to have measurable NADH:menadione oxidoreductase activity. Although a common feature of this family of enzymes, no biological relevance is proposed. The CoADR from T. thermophilus is a soluble homodimeric enzyme. Expression of the recombinant TtCoADR at high levels in E. coli results in a small fraction that co-purifies with the membrane fraction, which was used previously to isolate the enzyme wrongly identified as a membrane-bound NDH-2. It is concluded that T. thermophilus does not contain an authentic NDH-2 component in its aerobic respiratory chain.
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Affiliation(s)
- Andrea M Lencina
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA
| | - Juergen Koepke
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany
| | - Julia Preu
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany
| | - Cornelia Muenke
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA
| | - Hartmut Michel
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany.
| | - Lici A Schurig-Briccio
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA.
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Teanphonkrang S, Ernst A, Janke S, Chaiyen P, Sucharitakul J, Suginta W, Khunkaewla P, Schuhmann W, Schulte A, Ruff A. Amperometric Detection of the Urinary Disease Biomarker p-HPA by Allosteric Modulation of a Redox Polymer-Embedded Bacterial Reductase. ACS Sens 2019; 4:1270-1278. [PMID: 30968691 DOI: 10.1021/acssensors.9b00144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report an amperometric biosensor for the urinary disease biomarker para-hydroxyphenylacetate ( p-HPA) in which the allosteric reductase component of a bacterial hydroxylase, C1-hpah, is electrically wired to glassy carbon electrodes through incorporation into a low-potential Os-complex modified redox polymer. The proposed biosensing strategy depends on allosteric modulation of C1-hpah by the binding of the enzyme activator and analyte p-HPA, stimulating oxidation of the cofactor NADH. The pronounced concentration-dependence of allosteric C1-hpah modulation in the presence of a constant concentration of NADH allowed sensitive quantification of the target, p-HPA. The specific design of the immobilizing redox polymer with suitably low working potential allowed biosensor operation without the risk of co-oxidation of potentially interfering substances, such as uric acid or ascorbic acid. Optimized sensors were successfully applied for p-HPA determination in artificial urine, with good recovery rates and reproducibility and sub-micromolar detection limits. The proposed application of the allosteric enzyme C1-hpah for p-HPA trace electroanalysis is the first successful example of simple amperometric redox enzyme/redox polymer biosensing in which the analyte acts as an effector, modulating the activity of an immobilized biocatalyst. A general advantage of the concept of allosterically modulated biosensing is its ability to broaden the range of approachable analytes, through the move from substrate to effector detection.
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Affiliation(s)
- Somjai Teanphonkrang
- School of Chemistry, Institute of Science, Biochemistry - Electrochemistry Research Unit (BECRU), Suranaree University of Technology, 30000 Nakhon Ratchasima, Thailand
| | - Andrzej Ernst
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Salome Janke
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 21210 Rayong, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, 10330 Bangkok, Thailand
| | - Wipa Suginta
- School of Chemistry, Institute of Science, Biochemistry - Electrochemistry Research Unit (BECRU), Suranaree University of Technology, 30000 Nakhon Ratchasima, Thailand
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 21210 Rayong, Thailand
| | - Panida Khunkaewla
- School of Chemistry, Institute of Science, Biochemistry - Electrochemistry Research Unit (BECRU), Suranaree University of Technology, 30000 Nakhon Ratchasima, Thailand
| | - Wolfgang Schuhmann
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Albert Schulte
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 21210 Rayong, Thailand
| | - Adrian Ruff
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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Heras A, Vulcano F, Garoz-Ruiz J, Porcelli N, Terzi F, Colina A, Seeber R, Zanardi C. A Flexible Platform of Electrochemically Functionalized Carbon Nanotubes for NADH Sensors. Sensors (Basel) 2019; 19:s19030518. [PMID: 30691171 PMCID: PMC6386930 DOI: 10.3390/s19030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 01/14/2023]
Abstract
A flexible electrode system entirely constituted by single-walled carbon nanotubes (SWCNTs) has been proposed as the sensor platform for β-nicotinamide adenine dinucleotide (NADH) detection. The performance of the device, in terms of potential at which the electrochemical process takes place, significantly improves by electrochemical functionalization of the carbon-based material with a molecule possessing an o-hydroquinone residue, namely caffeic acid. Both the processes of SWCNT functionalization and NADH detection have been studied by combining electrochemical and spectroelectrochemical experiments, in order to achieve direct evidence of the electrode modification by the organic residues and to study the electrocatalytic activity of the resulting material in respect to functional groups present at the electrode/solution interface. Electrochemical measurements performed at the fixed potential of +0.30 V let us envision the possible use of the device as an amperometric sensor for NADH detection. Spectroelectrochemistry also demonstrates the effectiveness of the device in acting as a voltabsorptometric sensor for the detection of this same analyte by exploiting this different transduction mechanism, potentially less prone to the possible presence of interfering species.
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Affiliation(s)
- Aranzazu Heras
- Department of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain.
| | - Fabio Vulcano
- Department of Chemical and Geological Sciences, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.
- Institute of Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), via P. Gobetti 101, 40129 Bologna, Italy.
| | - Jesus Garoz-Ruiz
- Department of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain.
| | - Nicola Porcelli
- Department of Chemical and Geological Sciences, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.
| | - Fabio Terzi
- Department of Chemical and Geological Sciences, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.
| | - Alvaro Colina
- Department of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain.
| | - Renato Seeber
- Department of Chemical and Geological Sciences, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.
- Institute of Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), via P. Gobetti 101, 40129 Bologna, Italy.
| | - Chiara Zanardi
- Department of Chemical and Geological Sciences, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.
- Institute of Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), via P. Gobetti 101, 40129 Bologna, Italy.
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Vodenicarovova M, Skalska H, Holecek M. Deproteinization is Necessary for the Accurate Determination of Ammonia Levels by Glutamate Dehydrogenase Assay in Blood Plasma From Subjects With Liver Injury. Lab Med 2018; 48:339-345. [PMID: 29126300 DOI: 10.1093/labmed/lmx053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Objective To determine the effect of presence of high concentrations of nicotinamide adenine dinucleotide (NADH)- and nicotinamide adenine dinucleotide phosphate (NADPH)-consuming enzymes on the accuracy of glutamate dehydrogenase (GLDH) assay for ammonia. Methods We measured ammonia concentrations using GLDH and NADH or NADPH in blood-plasma specimens and specimens deproteinized by sulfosalicylic acid from CCl4-treated or control rats. The nonspecific oxidation of NADH and NADPH was measured in mixtures without GLDH. Results We observed a gradual decrease (~0.5%) in absorbance in the plasma of controls after the addition of NADH but not after adding NADPH. The decrease in absorbance in plasma of CCl4-treated animals was 13.2% and 5.2% after the addition of NADH and NADPH, respectively. The decrease in absorbance was not detected in deproteinized specimens. The values of ammonia concentration were higher in the plasma specimens compared with the deproteinized ones. Conclusion Deproteinization is necessary for accurate measurement of ammonia using GLDH assay in the blood plasma of subjects with liver injury.
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Affiliation(s)
- Melita Vodenicarovova
- Department of Physiology, Charles University, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Hana Skalska
- Department of Informatics and Quantitative Methods, Faculty of Informatics and Management, University of Hradec Kralove, Czech Republic
| | - Milan Holecek
- Department of Physiology, Charles University, Faculty of Medicine in Hradec Kralove, Czech Republic
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Koochana PK, Mohanty A, Das S, Subhadarshanee B, Satpati S, Dixit A, Sabat SC, Behera RK. Releasing iron from ferritin protein nanocage by reductive method: The role of electron transfer mediator. Biochim Biophys Acta Gen Subj 2018; 1862:1190-1198. [PMID: 29471025 DOI: 10.1016/j.bbagen.2018.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ferritin detoxifies excess of free Fe(II) and concentrates it in the form of ferrihydrite (Fe2O3·xH2O) mineral. When in need, ferritin iron is released for cellular metabolic activities. However, the low solubility of Fe(III) at neutral pH, its encapsulation by stable protein nanocage and presence of dissolved O2 limits in vitro ferritin iron release. METHODS Physiological reducing agent, NADH (E1/2 = -330 mV) was inefficient in releasing the ferritin iron (E1/2 = +183 mV), when used alone. Thus, current work investigates the role of low concentration (5-50 μM) of phenazine based electron transfer (ET) mediators such as FMN, PYO - a redox active virulence factor secreted by Pseudomonas aeruginosa and PMS towards iron mobilization from recombinant frog M ferritin. RESULTS The presence of dissolved O2, resulting in initial lag phase and low iron release in FMN, had little impact in case of PMS and PYO, reflecting their better ET relay ability that facilitates iron mobilization. The molecular modeling as well as fluorescence studies provided further structural insight towards interaction of redox mediators on ferritin surface for electron relay. CONCLUSIONS Reductive mobilization of iron from ferritin is dependent on the relative rate of NADH oxidation, dissolved O2 consumption and mineral core reduction, which in turn depends on E1/2 of these mediators and their interaction with ferritin. GENERAL SIGNIFICANCE The current mechanism of in vitro iron mobilization from ferritin by using redox mediators involves different ET steps, which may help to understand the iron release pathway in vivo and to check microbial growth.
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Affiliation(s)
| | - Abhinav Mohanty
- Department of Chemistry, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Suman Das
- Department of Chemistry, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Biswamaitree Subhadarshanee
- Department of Chemistry, National Institute of Technology, Rourkela 769008, Odisha, India; KIIT School of Biotechnology, KIIT University, Bhubaneswar 751024, Odisha, India
| | - Suresh Satpati
- Institute of Life Sciences, Bhubaneswar 751023, Odisha, India
| | - Anshuman Dixit
- Institute of Life Sciences, Bhubaneswar 751023, Odisha, India
| | | | - Rabindra K Behera
- Department of Chemistry, National Institute of Technology, Rourkela 769008, Odisha, India.
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Lorencova L, Bertok T, Dosekova E, Holazova A, Paprckova D, Vikartovska A, Sasinkova V, Filip J, Kasak P, Jerigova M, Velic D, Mahmoud KA, Tkac J. Electrochemical performance of Ti 3C 2T x MXene in aqueous media: towards ultrasensitive H2O2 sensing. Electrochim Acta 2017; 235:471-479. [PMID: 29109588 DOI: 10.1016/j.electacta.2017.03.073] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An extensive characterization of pristine and oxidized Ti3C2Tx (T: =O, -OH, -F) MXene showed that exposure of MXene to an anodic potential in the aqueous solution oxidizes the nanomaterial forming TiO2 layer or TiO2 domains with subsequent TiO2 dissolution by F- ions, making the resulting nanomaterial less electrochemically active compared to the pristine Ti3C2Tx. The Ti3C2Tx could be thus applied for electrochemical reactions in a cathodic potential window i.e. for ultrasensitive detection of H2O2 down to nM level with a response time of approx. 10 s. The manuscript also shows electrochemical behavior of Ti3C2Tx modified electrode towards oxidation of NADH and towards oxygen reduction reactions.
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Affiliation(s)
- Lenka Lorencova
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Tomas Bertok
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Erika Dosekova
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Alena Holazova
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Darina Paprckova
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Alica Vikartovska
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Vlasta Sasinkova
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
| | - Jaroslav Filip
- Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Peter Kasak
- Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Monika Jerigova
- Department of Physical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, Bratislava, 84215, Slovak Republic.,International Laser Centre, Ilkovi9cova 3, Bratislava 84104, Slovak Republic
| | - Dusan Velic
- Department of Physical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, Bratislava, 84215, Slovak Republic.,International Laser Centre, Ilkovi9cova 3, Bratislava 84104, Slovak Republic
| | - Khaled A Mahmoud
- Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), P.O. Box 5825, Doha, Qatar
| | - Jan Tkac
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 845 38, Slovak Republic
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Abstract
The Barth syndrome (BTHS) is caused by an inborn error of metabolism that manifests characteristic phenotypic features including altered mitochondrial membrane phospholipids, lactic acidosis, organic acid-uria, skeletal muscle weakness and cardiomyopathy. The underlying cause of BTHS has been definitively traced to mutations in the tafazzin (TAZ) gene locus on chromosome X. TAZ encodes a phospholipid transacylase that promotes cardiolipin acyl chain remodeling. Absence of tafazzin activity results in cardiolipin molecular species heterogeneity, increased levels of monolysocardiolipin and lower cardiolipin abundance. In skeletal muscle and cardiac tissue mitochondria these alterations in cardiolipin perturb the inner membrane, compromising electron transport chain function and aerobic respiration. Decreased electron flow from fuel metabolism via NADH ubiquinone oxidoreductase activity leads to a buildup of NADH in the matrix space and product inhibition of key TCA cycle enzymes. As TCA cycle activity slows pyruvate generated by glycolysis is diverted to lactic acid. In turn, Cori cycle activity increases to supply muscle with glucose for continued ATP production. Acetyl CoA that is unable to enter the TCA cycle is diverted to organic acid waste products that are excreted in urine. Overall, reduced ATP production efficiency in BTHS is exacerbated under conditions of increased energy demand. Prolonged deficiency in ATP production capacity underlies cell and tissue pathology that ultimately is manifest as dilated cardiomyopathy.
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Affiliation(s)
- Nikita Ikon
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA, 94609, USA
| | - Robert O Ryan
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA, 94609, USA.
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