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Iacobazzi D, Convertini P, Todisco S, Santarsiero A, Iacobazzi V, Infantino V. New Insights into NF-κB Signaling in Innate Immunity: Focus on Immunometabolic Crosstalks. Biology (Basel) 2023; 12:776. [PMID: 37372061 DOI: 10.3390/biology12060776] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023]
Abstract
The nuclear factor kappa B (NF-κB) is a family of transcription factors that, beyond their numberless functions in various cell processes, play a pivotal role in regulating immune cell activation. Two main pathways-canonical and non-canonical-are responsible for NF-κB activation and heterodimer translocation into the nucleus. A complex crosstalk between NF-κB signaling and metabolism is emerging in innate immunity. Metabolic enzymes and metabolites regulate NF-κB activity in many cases through post-translational modifications such as acetylation and phosphorylation. On the other hand, NF-κB affects immunometabolic pathways, including the citrate pathway, thereby building an intricate network. In this review, the emerging findings about NF-κB function in innate immunity and the interplay between NF-κB and immunometabolism have been discussed. These outcomes allow for a deeper comprehension of the molecular mechanisms underlying NF-κB function in innate immune cells. Moreover, the new insights are important in order to perceive NF-κB signaling as a potential therapeutic target for inflammatory/immune chronic diseases.
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Affiliation(s)
- Dominga Iacobazzi
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol BS2 8HW, UK
| | - Paolo Convertini
- Department of Science, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Simona Todisco
- Department of Science, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Anna Santarsiero
- Department of Science, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vittoria Infantino
- Department of Science, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
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2
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Infantino V, Pierri CL, Iacobazzi V. Metabolic Routes in Inflammation: The Citrate Pathway and its Potential as Therapeutic Target. Curr Med Chem 2020; 26:7104-7116. [PMID: 29745322 DOI: 10.2174/0929867325666180510124558] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [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: 01/31/2018] [Revised: 04/13/2018] [Accepted: 04/30/2018] [Indexed: 12/21/2022]
Abstract
Significant metabolic changes occur in inflammation to respond to the new energetic needs of cells. Mitochondria are addressed not only to produce ATP, but also to supply substrates, such citrate, to produce pro-inflammatory molecules. In this context, most of the citrate is diverted from Krebs cycle and channeled into the "citrate pathway" leading to the increase in the export of citrate into cytosol by the Mitochondrial Citrate Carrier (CIC) followed by its cleavage into acetyl-CoA and oxaloacetate by ATP Citrate Lyase (ACLY). Acetyl- CoA is used to produce PGE2 and oxaloacetate to make NADPH needed for NO and ROS production. In addition, cytosolic citrate also provides precursors for itaconate synthesis. Citrate- derived itaconate acts as a negative regulator of inflammation by modulating the synthesis of the inflammatory mediators. Inhibition of CIC or ACLY by different synthetic and natural molecules results in the reduction of NO, ROS and PGE2 levels suggesting that the citrate pathway can be a new target to be addressed in inflammation. Beneficial effects can be obtained also in the oxidative stress and inflammatory conditions observed in Down syndrome.
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Affiliation(s)
| | - Ciro Leonardo Pierri
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
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3
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Cianciulli A, Menga A, Ferdinando P, Iacobazzi V. FOXD3 acts as a repressor of the mitochondrial S-adenosylmethionine carrier (SLC25A26) gene expression in cancer cells. Biochimie 2018; 154:25-34. [DOI: 10.1016/j.biochi.2018.07.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 07/30/2018] [Indexed: 01/24/2023]
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4
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Iacobazzi V, Infantino V, Castegna A, Menga A, Palmieri EM, Convertini P, Palmieri F. Mitochondrial carriers in inflammation induced by bacterial endotoxin and cytokines. Biol Chem 2017; 398:303-317. [PMID: 27727142 DOI: 10.1515/hsz-2016-0260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/02/2016] [Indexed: 12/18/2022]
Abstract
Significant metabolic changes occur in the shift from resting to activated cellular status in inflammation. Thus, changes in expression of a large number of genes and extensive metabolic reprogramming gives rise to acquisition of new functions (e.g. production of cytokines, intermediates for biosynthesis, lipid mediators, PGE, ROS and NO). In this context, mitochondrial carriers, which catalyse the transport of solute across mitochondrial membrane, change their expression to transport mitochondrially produced molecules, among which citrate and succinate, to be used as intracellular signalling molecules in inflammation. This review summarises the mitochondrial carriers studied so far that are, directly or indirectly, involved in inflammation.
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Menga A, Palmieri EM, Cianciulli A, Infantino V, Mazzone M, Scilimati A, Palmieri F, Castegna A, Iacobazzi V. SLC25A26 overexpression impairs cell function via mtDNA hypermethylation and rewiring of methyl metabolism. FEBS J 2017; 284:967-984. [PMID: 28118529 DOI: 10.1111/febs.14028] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/01/2016] [Accepted: 01/20/2017] [Indexed: 12/22/2022]
Abstract
Cancer cells down-regulate different genes to give them a selective advantage in invasiveness and/or metastasis. The SLC25A26 gene encodes the mitochondrial carrier that catalyzes the import of S-adenosylmethionine (SAM) into the mitochondrial matrix, required for mitochondrial methylation processes, and is down-regulated in cervical cancer cells. In this study we show that SLC25A26 is down-regulated due to gene promoter hypermethylation, as a mechanism to promote cell survival and proliferation. Furthermore, overexpression of SLC25A26 in CaSki cells increases mitochondrial SAM availability and promotes hypermethylation of mitochondrial DNA, leading to decreased expression of key respiratory complex subunits, reduction of mitochondrial ATP and release of cytochrome c. In addition, increased SAM transport into mitochondria leads to impairment of the methionine cycle with accumulation of homocysteine at the expense of glutathione, which is strongly reduced. All these events concur to arrest the cell cycle in the S phase, induce apoptosis and enhance chemosensitivity of SAM carrier-overexpressing CaSki cells to cisplatin.
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Affiliation(s)
- Alessio Menga
- National Cancer Research Center, Istituto Tumori 'Giovanni Paolo II', Bari, Italy
| | - Erika M Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Italy
| | - Antonia Cianciulli
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Italy
| | | | - Massimiliano Mazzone
- Laboratory of Molecular Oncology and Angiogenesis, Department of Oncology, Vesalius Research Center, KU Leuven, Belgium
| | | | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Italy
| | - Alessandra Castegna
- National Cancer Research Center, Istituto Tumori 'Giovanni Paolo II', Bari, Italy.,Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari 'Aldo Moro', Italy
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6
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Piemontese L, Cerchia C, Laghezza A, Ziccardi P, Sblano S, Tortorella P, Iacobazzi V, Infantino V, Convertini P, Dal Piaz F, Lupo A, Colantuoni V, Lavecchia A, Loiodice F. New diphenylmethane derivatives as peroxisome proliferator-activated receptor alpha/gamma dual agonists endowed with anti-proliferative effects and mitochondrial activity. Eur J Med Chem 2017; 127:379-397. [DOI: 10.1016/j.ejmech.2016.12.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/21/2016] [Accepted: 12/23/2016] [Indexed: 12/18/2022]
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Convertini P, Menga A, Andria G, Scala I, Santarsiero A, Castiglione Morelli MA, Iacobazzi V, Infantino V. The contribution of the citrate pathway to oxidative stress in Down syndrome. Immunology 2016; 149:423-431. [PMID: 27502741 DOI: 10.1111/imm.12659] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [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: 02/07/2016] [Revised: 06/25/2016] [Accepted: 07/29/2016] [Indexed: 12/13/2022] Open
Abstract
Inflammatory conditions and oxidative stress have a crucial role in Down syndrome (DS). Emerging studies have also reported an altered lipid profile in the early stages of DS. Our previous works demonstrate that citrate pathway activation is required for oxygen radical production during inflammation. Here, we find up-regulation of the citrate pathway and down-regulation of carnitine/acylcarnitine carrier and carnitine palmitoyl-transferase 1 genes in cells from children with DS. Interestingly, when the citrate pathway is inhibited, we observe a reduction in oxygen radicals as well as in lipid peroxidation levels. Our preliminary findings provide evidence for a citrate pathway dysregulation, which could be related to some phenotypic traits of people with DS.
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Affiliation(s)
| | - Alessio Menga
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, Bari, Italy
| | - Generoso Andria
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Napoli, Italy
| | - Iris Scala
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Napoli, Italy
| | | | | | - Vito Iacobazzi
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, Bari, Italy.
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Abstract
The bidirectional cross talk between nuclear and mitochondrial DNA is essential for cellular homeostasis and proper functioning. Mitochondria depend on nuclear contribution for much of their functionality, but their activities have been recently recognized to control nuclear gene expression as well as cell function in many different ways. Epigenetic mechanisms, which tune gene expression in response to environmental stimuli, are key regulatory events at the interplay between mitochondrial and nuclear interactions. Emerging findings indicate that epigenetic factors can be targets or instruments of mitochondrial-nuclear cross talk. Additionally, the growing interest into mtDNA epigenetic modifications opens new avenues into the interaction mechanisms between mitochondria and nucleus. In this review we summarize the points of mitochondrial and nuclear reciprocal control involving epigenetic factors, focusing on the role of mitochondrial genome and metabolism in shaping epigenetic modulation of gene expression. The relevance of the new findings on the methylation of mtDNA is also highlighted as a new frontier in the complex scenario of mitochondrial-nuclear communication.
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Affiliation(s)
- Alessandra Castegna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro," Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro," Bari, Italy;
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro," Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro," Bari, Italy; CNR Institute of Biomembranes and Bioenergetics, Bari, Italy; and
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Palmieri EM, Spera I, Menga A, Infantino V, Porcelli V, Iacobazzi V, Pierri CL, Hooper DC, Palmieri F, Castegna A. Acetylation of human mitochondrial citrate carrier modulates mitochondrial citrate/malate exchange activity to sustain NADPH production during macrophage activation. Biochim Biophys Acta 2015; 1847:729-38. [PMID: 25917893 DOI: 10.1016/j.bbabio.2015.04.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/27/2015] [Accepted: 04/18/2015] [Indexed: 01/22/2023]
Abstract
The mitochondrial citrate-malate exchanger (CIC), a known target of acetylation, is up-regulated in activated immune cells and plays a key role in the production of inflammatory mediators. However, the role of acetylation in CIC activity is elusive. We show that CIC is acetylated in activated primary human macrophages and U937 cells and the level of acetylation is higher in glucose-deprived compared to normal glucose medium. Acetylation enhances CIC transport activity, leading to a higher citrate efflux from mitochondria in exchange with malate. Cytosolic citrate levels do not increase upon activation of cells grown in deprived compared to normal glucose media, indicating that citrate, transported from mitochondria at higher rates from acetylated CIC, is consumed at higher rates. Malate levels in the cytosol are lower in activated cells grown in glucose-deprived compared to normal glucose medium, indicating that this TCA intermediate is rapidly recycled back into the cytosol where it is used by the malic enzyme. Additionally, in activated cells CIC inhibition increases the NADP+/NADPH ratio in glucose-deprived cells; this ratio is unchanged in glucose-rich grown cells due to the activity of the pentose phosphate pathway. Consistently, the NADPH-producing isocitrate dehydrogenase level is higher in activated glucose-deprived as compared to glucose rich cells. These results demonstrate that, in the absence of glucose, activated macrophages increase CIC acetylation to enhance citrate efflux from mitochondria not only to produce inflammatory mediators but also to meet the NADPH demand through the actions of isocitrate dehydrogenase and malic enzyme.
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Affiliation(s)
- Erika M Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Iolanda Spera
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | | | - Vito Porcelli
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy; CNR Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Ciro L Pierri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Douglas C Hooper
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, USA; Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, USA
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy.
| | - Alessandra Castegna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy.
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10
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Abstract
Citrate is an important substrate in cellular energy metabolism. It is produced in the mitochondria and used in the Krebs cycle or released into cytoplasm through a specific mitochondrial carrier, CIC. In the cytosol, citrate and its derivatives, acetyl-CoA and oxaloacetate, are used in normal and pathological processes. Beyond the classical role as metabolic regulator, recent studies have highlighted that citrate is involved in inflammation, cancer, insulin secretion, histone acetylation, neurological disorders, and non-alcoholic fatty liver disease. Monitoring changes in the citrate levels could therefore potentially be used as diagnostic tool. This review highlights these new aspects of citrate functions.
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11
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Laghezza A, Montanari R, Lavecchia A, Piemontese L, Pochetti G, Iacobazzi V, Infantino V, Capelli D, De Bellis M, Liantonio A, Pierno S, Tortorella P, Conte Camerino D, Loiodice F. On the metabolically active form of metaglidasen: improved synthesis and investigation of its peculiar activity on peroxisome proliferator-activated receptors and skeletal muscles. ChemMedChem 2015; 10:555-65. [PMID: 25641779 DOI: 10.1002/cmdc.201402462] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [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: 10/24/2014] [Indexed: 01/27/2023]
Abstract
Metaglidasen is a fibrate-like drug reported as a selective modulator of peroxisome proliferator-activated receptor γ (PPARγ), able to lower plasma glucose levels in the absence of the side effects typically observed with thiazolidinedione antidiabetic agents in current use. Herein we report an improved synthesis of metaglidasen's metabolically active form halofenic acid (R)-2 and that of its enantiomer (S)-2. The activity of the two stereoisomers was carefully examined on PPARα and PPARγ subtypes. As expected, both showed partial agonist activity toward PPARγ; the investigation of PPARα activity, however, led to unexpected results. In particular, (S)-2 was found to act as a partial agonist, whereas (R)-2 behaved as an antagonist. X-ray crystallographic studies with PPARγ were carried out to gain more insight on the molecular-level interactions and to propose a binding mode. Given the adverse effects provoked by fibrate drugs on skeletal muscle function, we also investigated the capacity of (R)-2 and (S)-2 to block conductance of the skeletal muscle membrane chloride channel. The results showed a more beneficial profile for (R)-2, the activity of which on skeletal muscle function, however, should not be overlooked in the ongoing clinical trials studying its long-term effects.
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Affiliation(s)
- Antonio Laghezza
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", 70126 Bari (Italy)
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Kolukula VK, Sahu G, Wellstein A, Rodriguez OC, Preet A, Iacobazzi V, D'Orazi G, Albanese C, Palmieri F, Avantaggiati ML. SLC25A1, or CIC, is a novel transcriptional target of mutant p53 and a negative tumor prognostic marker. Oncotarget 2015; 5:1212-25. [PMID: 24681808 PMCID: PMC4012738 DOI: 10.18632/oncotarget.1831] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mutations of the p53 gene hallmark many human cancers. Several p53 mutant proteins acquire the capability to promote cancer progression and metastasis, a phenomenon defined as Gain of Oncogenic Function (GOF). The downstream targets by which GOF p53 mutants perturb cellular programs relevant to oncogenesis are only partially known. We have previously demonstrated that SLC25A1 (CIC) promotes tumorigenesis, while its inhibition blunts tumor growth. We now report that CIC is a direct transcriptional target of several p53 mutants. We identify a novel interaction between mutant p53 (mutp53) and the transcription factor FOXO-1 which is responsible for regulation of CIC expression levels. Tumor cells harboring mutp53 display higher CIC levels relative to p53 null or wild-type tumors, and inhibition of CIC activity blunts mutp53-driven tumor growth, partially overcoming GOF activity. CIC inhibition also enhances the chemotherapeutic potential of platinum-based agents. Finally, we found that elevated CIC levels predict poor survival outcome in tumors hallmarked by high frequency of p53 mutations. Our results identify CIC as a novel target of mutp53 and imply that the employment of CIC inhibitors may improve survival rates and reduce chemo-resistance in tumors harboring these types of mutations, which are among the most intractable forms of cancers.
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Affiliation(s)
- Vamsi K Kolukula
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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Menga A, Iacobazzi V, Infantino V, Avantaggiati ML, Palmieri F. The mitochondrial aspartate/glutamate carrier isoform 1 gene expression is regulated by CREB in neuronal cells. Int J Biochem Cell Biol 2015; 60:157-66. [PMID: 25597433 PMCID: PMC4344217 DOI: 10.1016/j.biocel.2015.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 07/17/2014] [Revised: 12/04/2014] [Accepted: 01/06/2015] [Indexed: 12/22/2022]
Abstract
The aspartate/glutamate carrier isoform 1 is an essential mitochondrial transporter that exchanges intramitochondrial aspartate and cytosolic glutamate across the inner mitochondrial membrane. It is expressed in brain, heart and muscle and is involved in important biological processes, including myelination. However, the signals that regulate the expression of this transporter are still largely unknown. In this study we first identify a CREB binding site within the aspartate/glutamate carrier gene promoter that acts as a strong enhancer element in neuronal SH-SY5Y cells. This element is regulated by active, phosphorylated CREB protein and by signal pathways that modify the activity of CREB itself and, most noticeably, by intracellular Ca(2+) levels. Specifically, aspartate/glutamate carrier gene expression is induced via CREB by forskolin while it is inhibited by the PKA inhibitor, H89. Furthermore, the CREB-induced activation of gene expression is increased by thapsigargin, which enhances cytosolic Ca(2+), while it is inhibited by BAPTA-AM that reduces cytosolic Ca(2+) or by STO-609, which inhibits CaMK-IV phosphorylation. We further show that CREB-dependent regulation of aspartate/glutamate carrier gene expression occurs in neuronal cells in response to pathological (inflammation) and physiological (differentiation) conditions. Since this carrier is necessary for neuronal functions and is involved in myelinogenesis, our results highlight that targeting of CREB activity and Ca(2+) might be therapeutically exploited to increase aspartate/glutamate carrier gene expression in neurodegenerative diseases.
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Affiliation(s)
- Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vittoria Infantino
- Department of Science, University of Basilicata, Via N. Sauro 85, 85100 Potenza, Italy
| | - Maria Laura Avantaggiati
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy.
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Palmieri EM, Spera I, Menga A, Infantino V, Iacobazzi V, Castegna A. Glutamine synthetase desensitizes differentiated adipocytes to proinflammatory stimuli by raising intracellular glutamine levels. FEBS Lett 2014; 588:4807-14. [PMID: 25451225 DOI: 10.1016/j.febslet.2014.11.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [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: 09/04/2014] [Revised: 10/09/2014] [Accepted: 11/11/2014] [Indexed: 01/16/2023]
Abstract
The role of glutamine synthetase (GS) during adipocyte differentiation is unclear. Here, we assess the impact of GS on the adipocytic response to a proinflammatory challenge at different differentiation stages. GS expression at the late stages of differentiation desensitized mature adipocytes to bacterial lipopolysaccharide (LPS) by increasing intracellular glutamine levels. Furthermore, LPS-activated mature adipocytes were unable to produce inflammatory mediators; LPS sensitivity was rescued following GS inhibition and the associated drop in intracellular glutamine levels. The ability of adipocytes to differentially respond to LPS during differentiation negatively correlates to GS expression and intracellular glutamine levels. Hence, modulation of intracellular glutamine levels by GS expression represents an endogenous mechanism through which mature adipocytes control the inflammatory response.
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Affiliation(s)
- Erika Mariana Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Iolanda Spera
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | | | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy; CNR Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Alessandra Castegna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.
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Di Noia MA, Todisco S, Cirigliano A, Rinaldi T, Agrimi G, Iacobazzi V, Palmieri F. The human SLC25A33 and SLC25A36 genes of solute carrier family 25 encode two mitochondrial pyrimidine nucleotide transporters. J Biol Chem 2014; 289:33137-48. [PMID: 25320081 DOI: 10.1074/jbc.m114.610808] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown.
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Affiliation(s)
- Maria Antonietta Di Noia
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy, Department of Sciences, University of Basilicata, via N. Sauro 85, 85100 Potenza, Italy
| | - Simona Todisco
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Angela Cirigliano
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology "Charles Darwin," University of Rome La Sapienza, 00185 Rome, Italy, Associazione Gian Franco Lupo "Un Sorriso alla Vita," ASM Azienda Sanitaria Locale di Matera, via Montescaglioso 75100 Matera, Italy, and
| | - Teresa Rinaldi
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology "Charles Darwin," University of Rome La Sapienza, 00185 Rome, Italy
| | - Gennaro Agrimi
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Vito Iacobazzi
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy, Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Ferdinando Palmieri
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy, Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy
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Iacobazzi V, Infantino V, Castegna A, Andria G. Hyperhomocysteinemia: related genetic diseases and congenital defects, abnormal DNA methylation and newborn screening issues. Mol Genet Metab 2014; 113:27-33. [PMID: 25087163 DOI: 10.1016/j.ymgme.2014.07.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [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: 06/03/2014] [Revised: 07/14/2014] [Accepted: 07/14/2014] [Indexed: 01/25/2023]
Abstract
Homocysteine, a sulfur-containing amino acid derived from the methionine metabolism, is located at the branch point of two pathways of the methionine cycle, i.e. remethylation and transsulfuration. Gene abnormalities in the enzymes catalyzing reactions in both pathways lead to hyperhomocysteinemia. Hyperhomocysteinemia is associated with increased risk for congenital disorders, including neural tube closure defects, heart defects, cleft lip/palate, Down syndrome, and multi-system abnormalities in adults. Since hyperhomocysteinemia is known to affect the extent of DNA methylation, it is likely that abnormal DNA methylation during embryogenesis, may be a pathogenic factor for these congenital disorders. In this review we highlight the importance of homocysteinemia by describing the genes encoding for enzymes of homocysteine metabolism relevant to the clinical practice, especially cystathionine-β-synthase and methylenetetrahydrofolate reductase mutations, and the impairment of related metabolites levels. Moreover, a possible correlation between hyperhomocysteine and congenital disorders through the involvement of abnormal DNA methylation during embryogenesis is discussed. Finally, the relevance of present and future diagnostic tools such as tandem mass spectrometry and next generation sequencing in newborn screening is highlighted.
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Affiliation(s)
- Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes and Bioenergetics, Bari, Italy.
| | | | - Alessandra Castegna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Generoso Andria
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Naples, Italy
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17
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Infantino V, Iacobazzi V, Menga A, Avantaggiati ML, Palmieri F. A key role of the mitochondrial citrate carrier (SLC25A1) in TNFα- and IFNγ-triggered inflammation. Biochim Biophys Acta 2014; 1839:1217-1225. [PMID: 25072865 DOI: 10.1016/j.bbagrm.2014.07.013] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/02/2014] [Accepted: 07/18/2014] [Indexed: 12/20/2022]
Abstract
The chronic induction of inflammation underlies multiple pathological conditions, including metabolic, autoimmune disorders and cancer. The mitochondrial citrate carrier (CIC), encoded by the SLC25A1 gene, promotes the export of citrate from the mitochondria to the cytoplasm, a process that profoundly influences energy balance in the cells. We have previously shown that SLC25A1 is a target gene for lipopolysaccharide signaling and promotes the production of inflammatory mediators. We now demonstrate that SLC25A1 is induced at the transcriptional level by two key pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interferon-γ (IFNγ), and such induction involves the activity of the nuclear factor kappa B and STAT1 transcription factors. By studying the down-stream events following SLC25A1 activation during signals that mimic inflammation, we demonstrate that CIC is required for regulating the levels of nitric oxide and of prostaglandins by TNFα or IFNγ. Importantly, we show that the citrate exported from mitochondria via CIC and its downstream metabolic intermediate, acetyl-coenzyme A, are necessary for TNFα or IFNγ to induce nitric oxide and prostaglandin production. These findings provide the first line of evidence that the citrate export pathway, via CIC, is central for cytokine-induced inflammatory signals and shed new light on the relationship between energy metabolism and inflammation.
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Affiliation(s)
- Vittoria Infantino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy.,Department of Science, University of Basilicata, via N. Sauro 85, 85100 Potenza, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Maria Laura Avantaggiati
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy
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18
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Infantino V, Convertini P, Menga A, Iacobazzi V. MEF2C exon α: Role in gene activation and differentiation. Gene 2013; 531:355-62. [DOI: 10.1016/j.gene.2013.08.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 08/06/2013] [Accepted: 08/12/2013] [Indexed: 12/20/2022]
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19
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Infantino V, Iacobazzi V, Palmieri F, Menga A. ATP-citrate lyase is essential for macrophage inflammatory response. Biochem Biophys Res Commun 2013; 440:105-11. [DOI: 10.1016/j.bbrc.2013.09.037] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/06/2013] [Indexed: 12/16/2022]
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20
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Iacobazzi V, Castegna A, Infantino V, Andria G. Mitochondrial DNA methylation as a next-generation biomarker and diagnostic tool. Mol Genet Metab 2013; 110:25-34. [PMID: 23920043 DOI: 10.1016/j.ymgme.2013.07.012] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [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: 06/03/2013] [Revised: 07/12/2013] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
Abstract
Recent expansion of our knowledge on epigenetic changes strongly suggests that not only nuclear DNA (nDNA), but also mitochondrial DNA (mtDNA) may be subjected to epigenetic modifications related to disease development, environmental exposure, drug treatment and aging. Thus, mtDNA methylation is attracting increasing attention as a potential biomarker for the detection and diagnosis of diseases and the understanding of cellular behavior in particular conditions. In this paper we review the current advances in mtDNA methylation studies with particular attention to the evidences of mtDNA methylation changes in diseases and physiological conditions so far investigated. Technological advances for the analysis of epigenetic variations are promising tools to provide insights into methylation of mtDNA with similar resolution levels as those reached for nDNA. However, many aspects related to mtDNA methylation are still unclear. More studies are needed to understand whether and how changes in mtDNA methylation patterns, global and gene specific, are associated to diseases or risk factors.
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Affiliation(s)
- Vito Iacobazzi
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, via Orabona 4, 70125 Bari, Italy.
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21
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Menga A, Infantino V, Iacobazzi F, Convertini P, Palmieri F, Iacobazzi V. Insight into mechanism of in vitro insulin secretion increase induced by antipsychotic clozapine: role of FOXA1 and mitochondrial citrate carrier. Eur Neuropsychopharmacol 2013; 23:978-87. [PMID: 22959654 DOI: 10.1016/j.euroneuro.2012.08.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/03/2012] [Accepted: 08/20/2012] [Indexed: 12/13/2022]
Abstract
The use of clozapine and other antipsychotic drugs is known to be associated with a number of adverse metabolic side effects, including diabetes mellitus. These side effects could be, at least in part, the result of impaired islet cell function and abnormal insulin secretion, although the underlying mechanisms are unknown. The aim of this study is the identification of targets for clozapine related to the abnormal insulin secretion. We identify a specific activation of the transcriptional factor FOXA1, but not FOXA2 and FOXA3, by clozapine in HepG2 cells. Clozapine enhances FOXA1 DNA-binding and its transcriptional activity, increasing mitochondrial citrate carrier gene expression, which contains a FOXA1 site in its promoter. Haloperidol, a conventional antipsychotic drug, does not determine any increase of FOXA1 gene expression. We also demonstrate that clozapine upregulates FOXA1 and CIC gene expression in INS-1 cells only at basal glucose concentration. In addition, we find that abnormal insulin secretion in basal glucose conditions could be completely abolished by FOXA1 silencing in INS-1 cells treated with clozapine. The identification of FOXA1 as a novel target for clozapine may shed more light to understand molecular mechanism of abnormal insulin secretion during clozapine treatment.
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Affiliation(s)
- A Menga
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, Via Orabona 4, 70125 Bari, Italy
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22
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Abstract
The 2-oxoglutarate carrier (OGC) belongs to the mitochondrial carrier protein family whose members are responsible for the exchange of metabolites, cofactors and nucleotides between the cytoplasm and mitochondrial matrix. Initially, OGC was characterized by determining substrate specificity, kinetic parameters of transport, inhibitors and molecular probes that form covalent bonds with specific residues. It was shown that OGC specifically transports oxoglutarate and certain carboxylic acids. The substrate specificity combination of OGC is unique, although many of its substrates are also transported by other mitochondrial carriers. The abundant recombinant expression of bovine OGC in Escherichia coli and its ability to functionally reconstitute into proteoliposomes made it possible to deduce the individual contribution of each and every residue of OGC to the transport activity by a complete set of cys-scanning mutants. These studies give experimental support for a substrate binding site constituted by three major contact points on the even-numbered α-helices and identifies other residues as important for transport function through their crucial positions in the structure for conserved interactions and the conformational changes of the carrier during the transport cycle. The results of these investigations have led to utilize OGC as a model protein for understanding the transport mechanism of mitochondrial carriers.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences, Biotechnology and Pharmacological Sciences, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via E. Orabona 4, 70125 Bari, Italy.
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23
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Bonofiglio D, Santoro A, Martello E, Vizza D, Rovito D, Cappello AR, Barone I, Giordano C, Panza S, Catalano S, Iacobazzi V, Dolce V, Andò S. Mechanisms of divergent effects of activated peroxisome proliferator-activated receptor-γ on mitochondrial citrate carrier expression in 3T3-L1 fibroblasts and mature adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1027-36. [PMID: 23370576 DOI: 10.1016/j.bbalip.2013.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 01/16/2013] [Accepted: 01/18/2013] [Indexed: 12/14/2022]
Abstract
The citrate carrier (CIC), a nuclear-encoded protein located in the mitochondrial inner membrane, plays an important metabolic role in the transport of acetyl-CoA from the mitochondrion to the cytosol in the form of citrate for fatty acid and cholesterol synthesis. Citrate has been reported to be essential for fibroblast differentiation into fat cells. Because peroxisome proliferator-activated receptor-gamma (PPARγ) is known to be one of the master regulators of adipogenesis, we aimed to study the regulation of CIC by the PPARγ ligand rosiglitazone (BRL) in 3T3-L1 fibroblasts and in adipocytes. We demonstrated that BRL up-regulated CIC mRNA and protein levels in fibroblasts, while it did not elicit any effects in mature adipocytes. The enhancement of CIC levels upon BRL treatment was reversed using the PPARγ antagonist GW9662, addressing how this effect was mediated by PPARγ. Functional experiments using a reporter gene containing rat CIC promoter showed that BRL enhanced CIC promoter activity. Mutagenesis studies, electrophoretic-mobility-shift assay and chromatin-immunoprecipitation analysis revealed that upon BRL treatment, PPARγ and Sp1 are recruited on the Sp1-containing region within the CIC promoter, leading to an increase in CIC expression. In addition, mithramycin, a specific inhibitor for Sp1-DNA binding activity, abolished the PPARγ-mediated up-regulation of CIC in fibroblasts. The stimulatory effects of BRL disappeared in mature adipocytes in which PPARγ/Sp1 complex recruited SMRT corepressor to the Sp1 site of the CIC promoter. Taken together, our results contribute to clarify the molecular mechanisms by which PPARγ regulates CIC expression during the differentiation stages of fibroblasts into mature adipocytes.
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Affiliation(s)
- Daniela Bonofiglio
- Dept. Pharmacy, Health Sciences and Nutritional, University of Calabria, Cosenza, Italy
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24
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Laghezza A, Pochetti G, Lavecchia A, Fracchiolla G, Faliti S, Piemontese L, Di Giovanni C, Iacobazzi V, Infantino V, Montanari R, Capelli D, Tortorella P, Loiodice F. New 2-(aryloxy)-3-phenylpropanoic acids as peroxisome proliferator-activated receptor α/γ dual agonists able to upregulate mitochondrial carnitine shuttle system gene expression. J Med Chem 2012; 56:60-72. [PMID: 23171045 DOI: 10.1021/jm301018z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The preparation of a series of 2-(aryloxy)-3-phenylpropanoic acids, resulting from the introduction of different substituents into the biphenyl system of the previously reported peroxisome proliferator-activated receptor α/γ (PPARα/γ) dual agonist 1, allowed the identification of new ligands with higher potency on PPARα and fine-tuned moderate PPARγ activity. For the most promising stereoisomer (S)-16, X-ray and calorimetric studies in PPARγ revealed, at high ligand concentration, the presence of two molecules simultaneously bound to the receptor. On the basis of these results and docking experiments in both receptor subtypes, a molecular explanation was provided for its different behavior as a full and partial agonist of PPARα and PPARγ, respectively. The effects of (S)-16 on mitochondrial acylcarnitine carrier and carnitine-palmitoyl-transferase 1 gene expression, two key components of the carnitine shuttle system, were also investigated, allowing the hypothesis of a more beneficial pharmacological profile of this compound compared to the less potent PPARα agonist fibrates currently used in therapy.
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Affiliation(s)
- A Laghezza
- Dipartimento di Farmacia-Scienze del Farmaco and ‡Laboratorio di Biochimica e Biologia Molecolare, Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", 70126 Bari, Italy
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25
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Monné M, Miniero DV, Iacobazzi V, Bisaccia F, Fiermonte G. Erratum to: The mitochondrial oxoglutarate carrier: from identification to mechanism. J Bioenerg Biomembr 2012. [DOI: 10.1007/s10863-012-9487-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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26
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Indiveri C, Iacobazzi V, Tonazzi A, Giangregorio N, Infantino V, Convertini P, Console L, Palmieri F. The mitochondrial carnitine/acylcarnitine carrier: Function, structure and physiopathology. Mol Aspects Med 2011; 32:223-33. [DOI: 10.1016/j.mam.2011.10.008] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 10/11/2011] [Indexed: 01/01/2023]
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27
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Infantino V, Convertini P, Iacobazzi F, Pisano I, Scarcia P, Iacobazzi V. Identification of a novel Sp1 splice variant as a strong transcriptional activator. Biochem Biophys Res Commun 2011; 412:86-91. [PMID: 21798247 DOI: 10.1016/j.bbrc.2011.07.047] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 07/11/2011] [Indexed: 02/03/2023]
Abstract
The transcription factor Sp1 regulates expression of numerous genes involved in many cellular processes. Different post-transcriptional modifications can influence the transcriptional control activity and stability of Sp1. In addition to these modifications, alternative splicing isoforms may also be the basis of its distinct functional activities. In this study, we identified a novel alternative splice isoform of Sp1 named Sp1c. This variant is generated by exclusion of a short domain, which we designate α, through alternative splice acceptor site usage in the exon 3. The existence of this new isoform was confirmed in vivo by Western blotting analysis. Although at very low levels, Sp1c is ubiquitously expressed, as seen in its full-length Sp1. A preliminary characterization of Sp1c shows that: (a) Sp1c works as stronger activator of transcription than full-length Sp1; (b) percentage of HEK293 Sp1c-overexpressing cells is higher in G1 phase and lower in S phase than percentage of HEK293 Sp1-overexpressing cells.
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Affiliation(s)
- Vittoria Infantino
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy
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28
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Infantino V, Castegna A, Iacobazzi F, Spera I, Scala I, Andria G, Iacobazzi V. Impairment of methyl cycle affects mitochondrial methyl availability and glutathione level in Down's syndrome. Mol Genet Metab 2011; 102:378-82. [PMID: 21195648 DOI: 10.1016/j.ymgme.2010.11.166] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 11/25/2010] [Accepted: 11/25/2010] [Indexed: 11/23/2022]
Abstract
In Down's syndrome there is evidence that increased gene expression coding for specific cystathionine beta-synthase translates directly into biochemical aberrations, which result in a biochemical and metabolic imbalance of the methyl status. This event is destined to impact mitochondrial function since methylation is a necessary event in mitochondria and relies on the availability and uptake of the methyl donor S-adenosylmethionine. Indeed mitochondrial dysfunctions have been widely described in Down's syndrome, but they have never been correlated to a possible mitochondrial methyl unbalance. In the present study we find that the mitochondrial levels of S-adenosylmethionine are reduced in Down's syndrome compared to control cells demonstrating the effect of the methyl unbalance on mitochondria. The possible role of methylation in mitochondria is discussed and some preliminary results on a possible methylation target are presented.
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Iacobazzi V, Infantino V, Convertini P, Vozza A, Agrimi G, Palmieri F. Transcription of the mitochondrial citrate carrier gene: Identification of a silencer and its binding protein ZNF224. Biochem Biophys Res Commun 2009; 386:186-91. [DOI: 10.1016/j.bbrc.2009.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 11/30/2022]
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30
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Iacobazzi V, Infantino V, Bisaccia F, Castegna A, Palmieri F. Role of FOXA in mitochondrial citrate carrier gene expression and insulin secretion. Biochem Biophys Res Commun 2009; 385:220-4. [PMID: 19445897 DOI: 10.1016/j.bbrc.2009.05.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 05/11/2009] [Indexed: 11/30/2022]
Abstract
In this study, we have investigated the transcriptional role of the FOXA site present in the promoter of the mitochondrial citrate carrier (CIC) gene. We have shown that wild-type (but not mutated) CIC FOXA site cloned in front of the luciferase promoter confers transcriptional activation of the gene reporter, particularly in cells overexpressing FOXA1. We have also demonstrated that overexpression and silencing of FOXA increases and reduces CIC transcript and protein levels, respectively. In addition, FOXA1 silencing in INS-1 cells decreases not only CIC mRNA and protein but also the amount of citrate in the cytosol and glucose-stimulated insulin secretion. These results show that FOXA plays a role in the transcriptional regulation of CIC and in insulin secretion.
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Affiliation(s)
- Vito Iacobazzi
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy
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31
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Iacobazzi V, Infantino V, Palmieri F. Epigenetic mechanisms and Sp1 regulate mitochondrial citrate carrier gene expression. Biochem Biophys Res Commun 2008; 376:15-20. [DOI: 10.1016/j.bbrc.2008.08.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 08/06/2008] [Indexed: 01/05/2023]
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32
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De Lucas JR, Indiveri C, Tonazzi A, Perez P, Giangregorio N, Iacobazzi V, Palmieri F. Functional characterization of residues within the carnitine/acylcarnitine translocase RX2PANAAXF distinct motif. Mol Membr Biol 2008; 25:152-63. [PMID: 18307102 DOI: 10.1080/09687680701697476] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The mitochondrial carnitine/acylcarnitine carrier (CAC) is characterized by the presence of a distinct motif, RXXPANAAXF, within its sixth transmembrane alpha-helix. In this study, we analysed the role of the amino acids of this motif in the structure-function relationships of the human CAC by using two complementary approaches. First, we performed functional analysis in the model fungus Aspergillus nidulans of selected mutations with structural and functional relevance. Second, similar mutant human CACs were biochemically characterized after their reconstitution into liposomes. Both analyses have provided relevant information on the importance and role of the CAC motif residues in the activity and metabolic function of CAC. Only the two adjacent alanines, Ala281 and Ala282 in the human CAC, have been found not to be crucial for transport activity and in vivo function. Results obtained from amino acid substitutions of residues Arg275, Asn280 and Phe284 of human CAC together with structural analysis using molecular modelling of the carrier suggest that R275, N280 and F284 are involved in substrate binding during acylcarnitine/carnitine translocation. Furthermore, functional analysis of mutations of residues Pro278 and Ala279 in A. nidulans, together with kinetic data in reconstituted liposomes, suggest a predominant structural role for these amino acids.
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Affiliation(s)
- J Ramon De Lucas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Universitario, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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33
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Infantino V, Iacobazzi V, De Santis F, Mastrapasqua M, Palmieri F. Transcription of the mitochondrial citrate carrier gene: role of SREBP-1, upregulation by insulin and downregulation by PUFA. Biochem Biophys Res Commun 2007; 356:249-54. [PMID: 17350599 DOI: 10.1016/j.bbrc.2007.02.114] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 02/22/2007] [Indexed: 11/16/2022]
Abstract
In this study we investigated the transcriptional role of the sterol regulatory element (SRE) present in the promoter of the mitochondrial citrate carrier (CIC). We show that wild-type (but not mutated) CIC SRE cloned in front of the luciferase promoter confers transcriptional activation of the gene reporter. We also demonstrate that insulin activates, and polyunsaturated fatty acids (PUFA) inhibit, the gene reporter activity driven by the CIC promoter containing wild-type (but not mutated) SRE. Finally, both insulin treatment and overexpression of SRE binding protein (SREBP-1) increase the CIC transcript and protein levels, whereas PUFA have an opposite effect. These results show that SRE/SREBP-1 play a role in the transcriptional regulation of CIC by insulin and PUFA.
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Affiliation(s)
- Vittoria Infantino
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy
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Palmieri F, Agrimi G, Blanco E, Castegna A, Di Noia MA, Iacobazzi V, Lasorsa FM, Marobbio CMT, Palmieri L, Scarcia P, Todisco S, Vozza A, Walker J. Identification of mitochondrial carriers in Saccharomyces cerevisiae by transport assay of reconstituted recombinant proteins. Biochim Biophys Acta 2006; 1757:1249-62. [PMID: 16844075 DOI: 10.1016/j.bbabio.2006.05.023] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 05/12/2006] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
The inner membranes of mitochondria contain a family of carrier proteins that are responsible for the transport in and out of the mitochondrial matrix of substrates, products, co-factors and biosynthetic precursors that are essential for the function and activities of the organelle. This family of proteins is characterized by containing three tandem homologous sequence repeats of approximately 100 amino acids, each folded into two transmembrane alpha-helices linked by an extensive polar loop. Each repeat contains a characteristic conserved sequence. These features have been used to determine the extent of the family in genome sequences. The genome of Saccharomyces cerevisiae contains 34 members of the family. The identity of five of them was known before the determination of the genome sequence, but the functions of the remaining family members were not. This review describes how the functions of 15 of these previously unknown transport proteins have been determined by a strategy that consists of expressing the genes in Escherichia coli or Saccharomyces cerevisiae, reconstituting the gene products into liposomes and establishing their functions by transport assay. Genetic and biochemical evidence as well as phylogenetic considerations have guided the choice of substrates that were tested in the transport assays. The physiological roles of these carriers have been verified by genetic experiments. Various pieces of evidence point to the functions of six additional members of the family, but these proposals await confirmation by transport assay. The sequences of many of the newly identified yeast carriers have been used to characterize orthologs in other species, and in man five diseases are presently known to be caused by defects in specific mitochondrial carrier genes. The roles of eight yeast mitochondrial carriers remain to be established.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via E. Orabona 4, 70125 Bari, Italy.
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Iacobazzi V, Infantino V, Costanzo P, Izzo P, Palmieri F. Functional analysis of the promoter of the mitochondrial phosphate carrier human gene: identification of activator and repressor elements and their transcription factors. Biochem J 2006; 391:613-21. [PMID: 15984930 PMCID: PMC1276962 DOI: 10.1042/bj20050776] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The phosphate carrier (PiC) catalyses the import of phosphate into mitochondria where it is needed for ATP synthesis. We have analysed the 5'-flanking region of the human PiC gene and found that it has a single transcriptional initiation site and lacks a TATA box. Through deletion analysis of the -1213/-25 nt region, we identified an activation domain (-223/-25) and an inhibition domain (-1017/-814). The most effective promoter activity in transfected HeLa cells corresponded to the region containing putative binding sites for Sp1 (-163/-142; where Sp1 stands for stimulating protein-1) and CREB (-138/-116; where CREB stands for cAMP-response-element-binding protein). These DNA sequences were active in gel-shift assays in the presence of HeLa cell nuclear extracts or recombinant Sp1 and CREB respectively. Forskolin increased PiC promoter activity via the CREB site. Both footprinting and transfection of deletion constructs of the inhibition region (-1017/-814) showed that PiC silencer activity extends over 25 nt (-943/-919), which specifically binds two proteins present in HeLa cell nuclear extracts. These transcription factors were purified by DNA affinity, analysed by MS and identified as p54(nrb)/NonO (nuclear RNA binding protein) and PSF (protein-associated splicing factor). The PiC silencer region cloned in front of the ferritin promoter conferred a strong inhibition to the heterologous promoter. These findings may provide insight into control of PiC gene expression in different cell types and under different growth conditions. To our knowledge, this is the first study to analyse the regulation of the PiC gene expression in any cell.
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Affiliation(s)
- Vito Iacobazzi
- *Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vittoria Infantino
- *Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Paola Costanzo
- †Department of Biochemistry and Medical Biotechnology, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Paola Izzo
- †Department of Biochemistry and Medical Biotechnology, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Ferdinando Palmieri
- *Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Via Orabona 4, 70125 Bari, Italy
- ‡Institute of Biomembranes and Bioenergetics, CNR (Consiglio Nazionale delle Ricerche), Via Orabona 4, 70125 Bari, Italy
- To whom correspondence should be addressed (email )
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Iacobazzi V, Invernizzi F, Baratta S, Pons R, Chung W, Garavaglia B, Dionisi-Vici C, Ribes A, Parini R, Huertas MD, Roldan S, Lauria G, Palmieri F, Taroni F. Molecular and functional analysis of SLC25A20 mutations causing carnitine-acylcarnitine translocase deficiency. Hum Mutat 2005; 24:312-20. [PMID: 15365988 DOI: 10.1002/humu.20085] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The enzyme carnitine-acylcarnitine translocase (CACT) is involved in the transport of long-chain fatty acids into mitochondria. CACT deficiency is a life-threatening, recessively inherited disorder of lipid beta-oxidation which manifests in early infancy with hypoketotic hypoglycemia, cardiomyopathy, liver failure, and muscle weakness. We report here the clinical, biochemical, and molecular features of six CACT-deficient patients from Italy, Spain, and North America who exhibited significant clinical heterogeneity. In five patients (Patients 1, 2, 4, 5, and 6) the disease manifested in the neonatal period, while the remaining patient (Patient 3), the younger sibling of an infant who had died with clinical suspicion of fatty acid oxidation defect, has been treated since birth and was clinically asymptomatic at 4.5 years of age. Patients 1 and 4 were deceased within 6 months from the onset of this study, while the remaining four are still alive at 8, 4.5, 3.5, and 2 years, respectively. Sequence analysis of the CACT gene (SLC25A20) disclosed five novel mutations and three previously reported mutations. Three patients were homozygous for the identified mutations. Two of the novel mutations (c.718+1G>C and c.843+4_843+50del) altered the donor splice site of introns 7 and 8, respectively. The 47-nt deletion in intron 8 caused both skipping of exon 8 only and skipping of exons 6-8. Four mutations [[c.159dupT;c.163delA] ([p.Gly54Trp;p.Thr55Ala]) c.397C>T (p.Arg133Trp), c.691G>C (p.Asp231His), and c.842C>T (p.Ala281Val)] resulted in amino acid substitutions affecting evolutionarily conserved regions of the protein. Interestingly, one of these exonic mutations (p.Ala281Val) was associated with a splicing defect also characterized by skipping of exons 6-8. The deleterious effect of the p.Arg133Trp substitution was demonstrated by measuring CACT activity upon expression of the normal and the mutant protein in E. coli and functional reconstitution into liposomes. Combined analysis of clinical, biochemical, and molecular data failed to indicate a correlation between the phenotype and the genotype.
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Affiliation(s)
- Vito Iacobazzi
- Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Bari, Italy
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37
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Garavaglia S, Cambria MT, Miglio M, Ragusa S, Iacobazzi V, Palmieri F, D'Ambrosio C, Scaloni A, Rizzi M. The Structure of Rigidoporus lignosus Laccase Containing a Full Complement of Copper Ions, Reveals an Asymmetrical Arrangement for the T3 Copper Pair. J Mol Biol 2004; 342:1519-31. [PMID: 15364578 DOI: 10.1016/j.jmb.2004.07.100] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 06/30/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
Laccase is a multicopper blue oxidase that couples the four-electron reduction of oxygen with the oxidation of a broad range of organic substrates, including phenols and arylamines. The enzyme is the object of intense biotechnological research, due to its employment in bioremediation of soils and water as well as in other biotechnological applications. We report here the cDNA and protein sequences, the post-translational modifications, the crystallization and X-ray structure determination of a laccase from the white-rot fungus Rigidoporus lignosus. The amino acid residues sequence deduced from cDNA clearly identified a pre-sequence of 21 residues representing the signal for extra-cellular localization. Mass spectrometry analysis performed on the salvage enzyme, confirmed the deduced sequence and precisely mapped two glycosylation sites at Asn337 and Asn435, determining the nature of the bound glycosidic moieties. The crystal structure was determined at 1.7A resolution from perfectly hemihedrally twinned crystals, by molecular replacement technique. While the overall structure closely resembled those reported for other fungal laccases, the analysis of the T2/T3 trinuclear cluster revealed an unprecedented coordination sphere for the T3 copper pair. No bridging oxygen ligand was present between the two T3 copper ions, which were no longer symmetrically coordinated. The observed structure could represent an intermediate along the process of four-electron reduction of oxygen to water taking place at the trinuclear copper cluster.
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Affiliation(s)
- Silvia Garavaglia
- DiSCAFF-INFM, University of Piemonte Orientale A. Avogadro, 28100 Novara, Italy
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38
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Iacobazzi V, Pasquali M, Singh R, Matern D, Rinaldo P, Amat di San Filippo C, Palmieri F, Longo N. Response to therapy in carnitine/acylcarnitine translocase (CACT) deficiency due to a novel missense mutation. Am J Med Genet A 2004; 126A:150-5. [PMID: 15057979 DOI: 10.1002/ajmg.a.20573] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Deficiency of carnitine/acylcarnitine translocase (CACT) is an autosomal recessive disorder of the carnitine cycle resulting in the inability to transfer fatty acids across the inner mitochondrial membrane. Only a limited number of affected patients have been reported and the effect of therapy on this condition is still not well defined. Here, we report a new patient with this disorder and follow the response to therapy. Our patient was the product of a consanguineous marriage. He presented shortly after birth with cardiac myopathy and arrhythmia coupled with severe non-ketotic hypoglycemia. Initial metabolic studies indicated severe non-ketotic C6-C10 dicarboxylic aciduria, plasma carnitine deficiency, and a characteristic elevation of plasma C:16:0, C18:1, and C18:2 acylcarnitine species. Enzyme assay confirmed deficiency of CACT activity. Molecular studies indicated that this child was homozygous, and both parents heterozygous, for a single bp change converting glutamine 238 to arginine (Q238R). Therapy with a formula providing most of the fat via medium chain triglycerides (MCT) and carnitine supplementation reduced the concentration of long-chain acylcarnitines and reversed cardiac symptoms and the hypoglycemia. These results suggest that carnitine and MCT may be effective in treating this defect of long-chain fatty acid oxidation.
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Affiliation(s)
- Vito Iacobazzi
- Dipartimento Farmaco-Biologico, University of Bari, Italy
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Indiveri C, Giangregorio N, Iacobazzi V, Palmieri F. Site-directed mutagenesis and chemical modification of the six native cysteine residues of the rat mitochondrial carnitine carrier: implications for the role of cysteine-136. Biochemistry 2002; 41:8649-56. [PMID: 12093282 DOI: 10.1021/bi012183n] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
By use of site-directed mutagenesis in combination with chemical modification of mutated proteins, the role of the six Cys residues in the transport function of the rat mitochondrial carnitine carrier (CAC) was studied. Several CAC mutants, in which one or more Cys residues had been replaced with Ser, were overexpressed in Escherichia coli, purified, and reconstituted in liposomes. The efficiency of incorporation into liposomes of the reconstituted proteins was lower for all constructs lacking Cys-23. Single, double, and quadruple replacement mutants showed V(max) comparable to that of the wild type. On the basis of the values of internal and external transport affinities (K(m)) for carnitine and of their comparison with those measured in mitochondria, the recombinant CAC is oriented unidirectionally in the liposomes, right side out compared to mitochondria. Substitution of Cys-136 with Ser caused a nearly complete loss of sensitivity of the CAC to N-ethylmaleimide, (2-aminoethyl)methanethiosulfonate hydrobromide (MTSES), and other hydrophilic SH reagents but not to the very hydrophobic N-phenylmaleimide. The wild-type CAC and the mutants containing Cys-136 showed substrate protection against NEM and MTSES inhibition and against NEM labeling. The data show that none of the native cysteines is essential for the transport mechanism and that Cys-136 is the major target of SH reagents and raise the hypothesis that Cys-136 is accessible from the external medium and is located at, or near, the substrate binding site. A model of the CAC is proposed in which the matrix hydrophilic loop containing Cys-136 protrudes into the membrane between the transmembrane domains of the protein.
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Affiliation(s)
- Cesare Indiveri
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, 70125 Bari, Italy
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40
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Iacobazzi V, Ventura M, Fiermonte G, Prezioso G, Rocchi M, Palmieri F. Genomic organization and mapping of the gene (SLC25A19) encoding the human mitochondrial deoxynucleotide carrier (DNC). Cytogenet Cell Genet 2001; 93:40-2. [PMID: 11474176 DOI: 10.1159/000056945] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The deoxynucleotide carrier (DNC) transports deoxynucleotides into mitochondria and is therefore essential for mtDNA synthesis. The human DNC gene (SLC25A19) spans about 16.5 kb and consists of nine exons with the translation start site in exon 4. It is located on chromosome 17q25.3. Three transcripts, which differ in their 5' ends and are generated by alternative splicing, have been identified.
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Affiliation(s)
- V Iacobazzi
- Department of Pharmaco-Biology, University of Bari, via Orabona 4, 70125 Bari, Italy
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41
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Hsu BY, Iacobazzi V, Wang Z, Harvie H, Chalmers RA, Saudubray JM, Palmieri F, Ganguly A, Stanley CA. Aberrant mRNA splicing associated with coding region mutations in children with carnitine-acylcarnitine translocase deficiency. Mol Genet Metab 2001; 74:248-55. [PMID: 11592821 DOI: 10.1006/mgme.2001.3235] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This report describes three infants with genetic defects of carnitine-acylcarnitine translocase (CACT), an inner mitochondrial membrane carrier that is essential for long-chain fatty acid oxidation. Two of the patients were of European and Chinese origin; the third was from consanguineous Turkish parents. CACT activity was totally deficient in cultured skin fibroblasts from all three patients. Patient 1 was heterozygous for a paternal frameshift mutation (120 del T in exon 1) and a maternal lariat branch point mutation (-10 T --> G in intron 2). Patient 2 was heterozygous for the same lariat branch point (-10T --> G intron 2) mutation, derived from the father, and a maternal frameshift mutation (362 del G in exon 3). Patient 3 was homozygous for a frameshift mutation (306 del C in exon 3). All of the three frameshift mutations give rise to the same stop codon at amino acid residue 127 which is predicted to cause premature protein truncation. In addition, cDNA transcript analysis showed that these coding sequence mutations also increase the amount of aberrant mRNA splicing and exon skipping at distances up to 7.7 kb nucleotides from mutation sites. The data suggest that the stability of mRNA transcripts is decreased or the frequency of aberrant splicing is increased in the presence of CACT coding sequence mutations. These results confirm that CACT is the genetic locus of the recessive mutations responsible for the fatal defects of fatty acid metabolism previously associated with deficiency of translocase activity in these three cases.
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Affiliation(s)
- B Y Hsu
- Division of Endocrinology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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42
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IJlst L, van Roermund CW, Iacobazzi V, Oostheim W, Ruiter JP, Williams JC, Palmieri F, Wanders RJ. Functional analysis of mutant human carnitine acylcarnitine translocases in yeast. Biochem Biophys Res Commun 2001; 280:700-6. [PMID: 11162577 DOI: 10.1006/bbrc.2000.4178] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long chain fatty acids are translocated as carnitine esters across the mitochondrial inner membrane by carnitine acylcarnitine translocase (CACT). We report functional studies on the mutant CACT proteins from a severe and a mild patient with CACT deficiency. CACT activities in fibroblasts of both patients were markedly deficient with some residual activity (<1%) in the milder patient. Palmitate oxidation activity in cells from the severe patient was less than 5% but in the milder patient approximately 27% residual activity was found. Sequencing of the CACT cDNAs revealed a c.241G>A (G81R) in the severe and a c.955insC mutation (C-terminal extension of 21 amino acids (CACT(+21aa)) in the milder patient. The effect of both mutations on the protein was studied in a sensitive expression system based on the ability of human CACT to functionally complement a CACT-deletion strain of yeast. Expression in this strain revealed significant residual activity for CACT(+21aa), while the CACT(G81R) was inactive.
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Affiliation(s)
- L IJlst
- Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, 1100 DE Amsterdam, The Netherlands
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Piccininni S, Iacobazzi V, Lauria G, Rocchi M, Palmieri F. Assignment of the oxoglutarate carrier gene (SLC20A4) to human chromosome 17p13.3. Cytogenet Cell Genet 2000; 83:256-7. [PMID: 10072597 DOI: 10.1159/000015198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- S Piccininni
- Istituto di Genetica, Università di Bari, Bari, Italy
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Abstract
The mitochondrial carrier protein for carnitine has been identified in Saccharomyces cerevisiae. It is encoded by the gene CRC1 and is a member of the family of mitochondrial transport proteins. The protein has been over-expressed with a C-terminal His-tag in S. cerevisiae and isolated from mitochondria by nickel affinity chromatography. The purified protein has been reconstituted into proteoliposomes and its transport characteristics established. It transports carnitine, acetylcarnitine, propionylcarnitine and to a much lower extent medium- and long-chain acylcarnitines.
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Affiliation(s)
- L Palmieri
- Department of Pharmaco-Biology, University of Bari, Italy
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Iacobazzi V, Naglieri MA, Stanley CA, Wanders RJ, Palmieri F. The structure and organization of the human carnitine/acylcarnitine translocase (CACT1) gene2. Biochem Biophys Res Commun 1998; 252:770-4. [PMID: 9837782 DOI: 10.1006/bbrc.1998.9738] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The carnitine/acylcarnitine translocase (CACT) transports acylcarnitines into mitochondria in exchange for free carnitine and it is, therefore, essential for the fatty acid beta-oxidation pathway. We have determined the exon-intron structure of the human CACT gene, which is responsible for a genetic disorder of fatty acid oxidation called CACT deficiency. The gene spans about 16.5 kb and consists of nine exons with the translation start site in exon 1. All the splice acceptor and donor sites conform to the AG/GT rules. All the introns except one are located at the level of the sequences coding for the extramembranous loops of CACT. We have designed a series of intronic oligonucleotide primers for amplifying each of the CACT exons together with their flanking intronic sequences, in segments well suited to detect mutations that would affect splicing of mRNA as well as the coding sequence itself.
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Affiliation(s)
- V Iacobazzi
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Italy
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Indiveri C, Iacobazzi V, Giangregorio N, Palmieri F. Bacterial overexpression, purification, and reconstitution of the carnitine/acylcarnitine carrier from rat liver mitochondria. Biochem Biophys Res Commun 1998; 249:589-94. [PMID: 9731180 DOI: 10.1006/bbrc.1998.9197] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The carnitine/acylcarnitine carrier from rat liver mitochondria was overexpressed in Escherichia coli. The expressed protein, recovered as inclusion bodies, was solubilized with sarkosyl and purified by Sephadex G-200 and celite chromatography. A yield of 15 mg of purified transport protein per liter of cell culture was obtained. Upon reconstitution into liposomes, the purified carrier catalyzed a [3H]carnitine/carnitine exchange inhibited by maleimides, mercurials, and sulfobetaines. Carnitine esters of various lengths were also transported. The Km for carnitine uptake was 0.47 +/- 0.11 mM, the Vmax of the exchange was 0.78 +/- 0.24 mmol/min per gram of protein, and the Ki for octanoylcarnitine was 13.5 +/- 4.3 microM. The transport properties of the recombinant carrier were virtually identical to those of the native transporter. These studies represent the first overexpression of the functionally active mitochondrial carnitine/acylcarnitine carrier, thus enabling structure/function analysis of this protein by site-directed mutagenesis.
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Affiliation(s)
- C Indiveri
- Department of Pharmaco-Biology, University of Bari, Italy
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47
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Huizing M, Wendel U, Ruitenbeek W, Iacobazzi V, IJlst L, Veenhuizen P, Savelkoul P, van den Heuvel LP, Smeitink JA, Wanders RJ, Trijbels JM, Palmieri F. Carnitine-acylcarnitine carrier deficiency: identification of the molecular defect in a patient. J Inherit Metab Dis 1998; 21:262-7. [PMID: 9686371 DOI: 10.1023/a:1005324323401] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- M Huizing
- University Hospital, Department of Pediatrics, Nijmegen, The Netherlands
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Huizing M, Ruitenbeek W, van den Heuvel LP, Dolce V, Iacobazzi V, Smeitink JA, Palmieri F, Trijbels JM. Human mitochondrial transmembrane metabolite carriers: tissue distribution and its implication for mitochondrial disorders. J Bioenerg Biomembr 1998; 30:277-84. [PMID: 9733094 DOI: 10.1023/a:1020501021222] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondrial transmembrane carrier deficiencies are a recently discovered group of disorders, belonging to the so-called mitochondriocytopathies. We examined the human tissue distribution of carriers which are involved in the process of oxidative phosphorylation (adenine nucleotide translocator, phosphate carrier, and voltage-dependent anion channel) and some mitochondrial substrate carriers (2-oxoglutarate carrier, carnitine-acylcarnitine carrier, and citrate carrier). The tissue distribution on mRNA level of mitochondrial transport proteins appears to be roughly in correlation with the dependence of these tissues on mitochondrial energy production capacity. In general the main mRNA expression of carriers involved in mitochondrial energy metabolism occurs in skeletal muscle and heart. Expression in liver and pancreas differs between carriers. Expression in brain, placenta, lung, and kidney is lower than in the other tissues. Western and Northern blotting experiments show a comparable HVDAC1 protein and mRNA distribution for the tested tissues. Patient's studies showed that cultured skin fibroblasts may not be a reliable alternative for skeletal muscle in screening for human mitochondrial carrier defects.
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Affiliation(s)
- M Huizing
- Department of Pediatrics, University Hospital, Nijmegen, The Netherlands
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49
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Viggiano L, Iacobazzi V, Marzella R, Cassano C, Rocchi M, Palmieri F. Assignment of the carnitine/acylcarnitine translocase gene (CACT) to human chromosome band 3p21.31 by in situ hybridization. Cytogenet Cell Genet 1998; 79:62-3. [PMID: 9533014 DOI: 10.1159/000134684] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- L Viggiano
- Istituto di Genetica, Università di Bari, Italy
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50
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Huizing M, Iacobazzi V, Ijlst L, Savelkoul P, Ruitenbeek W, van den Heuvel L, Indiveri C, Smeitink J, Trijbels F, Wanders R, Palmieri F. Cloning of the human carnitine-acylcarnitine carrier cDNA and identification of the molecular defect in a patient. Am J Hum Genet 1997; 61:1239-45. [PMID: 9399886 PMCID: PMC1716087 DOI: 10.1086/301628] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The carnitine-acylcarnitine carrier (CAC) catalyzes the translocation of long-chain fatty acids across the inner mitochondrial membrane. We cloned and sequenced the human CAC cDNA, which has an open reading frame of 903 nucleotides. Northern blot studies revealed different expression levels of CAC in various human tissues. Furthermore, mutation analysis was performed for a CAC-deficient infant. Direct sequencing of the patient's cDNA revealed a homozygous cytosine nucleotide insertion. This insertion provokes a frameshift and an extension of the open reading frame with 23 novel codons. This is the first report documenting a mutation, in the CAC cDNA, responsible for mitochondrial beta-oxidation impairment.
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Affiliation(s)
- M Huizing
- University Hospital Nijmegen, Department of Pediatrics, The Netherlands
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