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Matera I, Miglionico R, Abruzzese V, Marchese G, Ventola GM, Castiglione Morelli MA, Bisaccia F, Ostuni A. A Regulator Role for the ATP-Binding Cassette Subfamily C Member 6 Transporter in HepG2 Cells: Effect on the Dynamics of Cell-Cell and Cell-Matrix Interactions. Int J Mol Sci 2023; 24:16391. [PMID: 38003580 PMCID: PMC10670978 DOI: 10.3390/ijms242216391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
There is growing evidence that various ATP-binding cassette (ABC) transporters contribute to the growth and development of tumors, but relatively little is known about how the ABC transporter family behaves in hepatocellular carcinoma (HCC), one of the most common cancers worldwide. Cellular model studies have shown that ABCC6, which belongs to the ABC subfamily C (ABCC), plays a role in the cytoskeleton rearrangement and migration of HepG2 hepatocarcinoma cells, thus highlighting its role in cancer biology. Deep knowledge on the molecular mechanisms underlying the observed results could provide therapeutic insights into the tumors in which ABCC6 is modulated. In this study, differential expression levels of mRNA transcripts between ABCC6-silenced HepG2 and control groups were measured, and subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. Real-Time PCR and Western blot analyses confirmed bioinformatics; functional studies support the molecular mechanisms underlying the observed effects. The results provide valuable information on the dysregulation of fundamental cellular processes, such as the focal adhesion pathway, which allowed us to obtain detailed information on the active role that the down-regulation of ABCC6 could play in the biology of liver tumors, as it is involved not only in cell migration but also in cell adhesion and invasion.
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Affiliation(s)
- Ilenia Matera
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (I.M.); (R.M.); (V.A.); (M.A.C.M.)
| | - Rocchina Miglionico
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (I.M.); (R.M.); (V.A.); (M.A.C.M.)
| | - Vittorio Abruzzese
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (I.M.); (R.M.); (V.A.); (M.A.C.M.)
| | - Giovanna Marchese
- Genomix4Life Srl, 84081 Baronissi, Italy; (G.M.); (G.M.V.)
- Genome Research Center for Health—CRGS, 84081 Baronissi, Italy
| | | | | | - Faustino Bisaccia
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (I.M.); (R.M.); (V.A.); (M.A.C.M.)
| | - Angela Ostuni
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (I.M.); (R.M.); (V.A.); (M.A.C.M.)
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2
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Plümers R, Lindenkamp C, Osterhage MR, Knabbe C, Hendig D. Matrix Metalloproteinases Contribute to the Calcification Phenotype in Pseudoxanthoma Elasticum. Biomolecules 2023; 13:672. [PMID: 37189419 PMCID: PMC10135689 DOI: 10.3390/biom13040672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/16/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Ectopic calcification and dysregulated extracellular matrix remodeling are prominent hallmarks of the complex heterogenous pathobiochemistry of pseudoxanthoma elasticum (PXE). The disease arises from mutations in ABCC6, an ATP-binding cassette transporter expressed predominantly in the liver. Neither its substrate nor the mechanisms by which it contributes to PXE are completely understood. The fibroblasts isolated from PXE patients and Abcc6-/- mice were subjected to RNA sequencing. A group of matrix metalloproteinases (MMPs) clustering on human chromosome 11q21-23, respectively, murine chromosome 9, was found to be overexpressed. A real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescent staining confirmed these findings. The induction of calcification by CaCl2 resulted in the elevated expression of selected MMPs. On this basis, the influence of the MMP inhibitor Marimastat (BB-2516) on calcification was assessed. PXE fibroblasts (PXEFs) exhibited a pro-calcification phenotype basally. PXEF and normal human dermal fibroblasts responded with calcium deposit accumulation and the induced expression of osteopontin to the addition of Marimastat to the calcifying medium. The raised MMP expression in PXEFs and during cultivation with calcium indicates a correlation of ECM remodeling and ectopic calcification in PXE pathobiochemistry. We assume that MMPs make elastic fibers accessible to controlled, potentially osteopontin-dependent calcium deposition under calcifying conditions.
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Affiliation(s)
| | | | | | | | - Doris Hendig
- Herz- und Diabeteszentrum Nordrhein-Westfalen, Institut für Laboratoriums- und Transfusionsmedizin, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany
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3
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Kozák E, Bartstra JW, de Jong PA, Mali WPTM, Fülöp K, Tőkési N, Pomozi V, Risseeuw S, Norel JOV, van Leeuwen R, Váradi A, Spiering W. Plasma Level of Pyrophosphate Is Low in Pseudoxanthoma Elasticum Owing to Mutations in the ABCC6 Gene, but It Does Not Correlate with ABCC6 Genotype. J Clin Med 2023; 12:jcm12031047. [PMID: 36769695 PMCID: PMC9917606 DOI: 10.3390/jcm12031047] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/04/2023] [Accepted: 01/22/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE), a monogenic disorder resulting in calcification affecting the skin, eyes and peripheral arteries, is caused by mutations in the ABCC6 gene, and is associated with low plasma inorganic pyrophosphate (PPi). It is unknown how ABCC6 genotype affects plasma PPi. METHODS We studied the association of ABCC6 genotype (192 patients with biallelic pathogenic ABCC6 mutations) and PPi levels, and its association with the severity of arterial and ophthalmological phenotypes. ABCC6 variants were classified as truncating or non-truncating, and three groups of the 192 patients were formed: those with truncating mutations on both chromosomes (n = 121), those with two non-truncating mutations (n = 10), and a group who had one truncating and one non-truncating ABCC6 mutation (n = 61). The hypothesis formulated before this study was that there was a negative association between PPi level and disease severity. RESULTS Our findings confirm low PPi in PXE compared with healthy controls (0.53 ± 0.15 vs. 1.13 ± 0.29 µM, p < 0.01). The PPi of patients correlated with increasing age (β: 0.05 µM, 95% CI: 0.03-0.06 per 10 years) and was higher in females (0.55 ± 0.17 vs. 0.51 ± 0.13 µM in males, p = 0.03). However, no association between PPi and PXE phenotypes was found. When adjusted for age and sex, no association between PPi and ABCC6 genotype was found. CONCLUSIONS Our data suggest that the relationship between ABCC6 mutations and reduced plasma PPi may not be as direct as previously thought. PPi levels varied widely, even in patients with the same ABCC6 mutations, further suggesting a lack of direct correlation between them, even though the ABCC6 protein-mediated pathway is responsible for ~60% of this metabolite in the circulation. We discuss potential factors that may perturb the expected associations between ABCC6 genotype and PPi and between PPi and disease severity. Our findings support the argument that predictions of pathogenicity made on the basis of mutations (or on the structure of the mutated protein) could be misleading.
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Affiliation(s)
- Eszter Kozák
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Jonas W. Bartstra
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Pim A. de Jong
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Willem P. T. M. Mali
- Department of Radiology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Krisztina Fülöp
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Natália Tőkési
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Viola Pomozi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Sara Risseeuw
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | | | - Redmer van Leeuwen
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - András Váradi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Center of Excellence, 1117 Budapest, Hungary
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-7571188
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4
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Mitochondrial Dysfunction and Oxidative Stress in Hereditary Ectopic Calcification Diseases. Int J Mol Sci 2022; 23:ijms232315288. [PMID: 36499615 PMCID: PMC9738718 DOI: 10.3390/ijms232315288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 11/26/2022] [Accepted: 12/01/2022] [Indexed: 12/08/2022] Open
Abstract
Ectopic calcification (EC) is characterized by an abnormal deposition of calcium phosphate crystals in soft tissues such as blood vessels, skin, and brain parenchyma. EC contributes to significant morbidity and mortality and is considered a major health problem for which no effective treatments currently exist. In recent years, growing emphasis has been placed on the role of mitochondrial dysfunction and oxidative stress in the pathogenesis of EC. Impaired mitochondrial respiration and increased levels of reactive oxygen species can be directly linked to key molecular pathways involved in EC such as adenosine triphosphate homeostasis, DNA damage signaling, and apoptosis. While EC is mainly encountered in common diseases such as diabetes mellitus and chronic kidney disease, studies in rare hereditary EC disorders such as pseudoxanthoma elasticum or Hutchinson-Gilford progeria syndrome have been instrumental in identifying the precise etiopathogenetic mechanisms leading to EC. In this narrative review, we describe the current state of the art regarding the role of mitochondrial dysfunction and oxidative stress in hereditary EC diseases. In-depth knowledge of aberrant mitochondrial metabolism and its local and systemic consequences will benefit the research into novel therapies for both rare and common EC disorders.
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Szeri F, Miko A, Navasiolava N, Kaposi A, Verschuere S, Molnar B, Li Q, Terry SF, Boraldi F, Uitto J, van de Wetering K, Martin L, Quaglino D, Vanakker OM, Tory K, Aranyi T. The pathogenic c.1171A>G (p.Arg391Gly) and c.2359G>A (p.Val787Ile) ABCC6 variants display incomplete penetrance causing pseudoxanthoma elasticum in a subset of individuals. Hum Mutat 2022; 43:1872-1881. [PMID: 36317459 PMCID: PMC9772137 DOI: 10.1002/humu.24498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/30/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
ABCC6 promotes ATP efflux from hepatocytes to bloodstream. ATP is metabolized to pyrophosphate, an inhibitor of ectopic calcification. Pathogenic variants of ABCC6 cause pseudoxanthoma elasticum, a highly variable recessive ectopic calcification disorder. Incomplete penetrance may initiate disease heterogeneity, hence symptoms may not, or differently manifest in carriers. Here, we investigated whether incomplete penetrance is a source of heterogeneity in pseudoxanthoma elasticum. By integrating clinical and genetic data of 589 patients, we created the largest European cohort. Based on allele frequency alterations, we identified two incomplete penetrant pathogenic variants, c.2359G>A (p.Val787Ile) and c.1171A>G (p.Arg391Gly), with 6.5% and 2% penetrance, respectively. However, when penetrant, the c.1171A>G (p.Arg391Gly) manifested a clinically unaltered severity. After applying in silico and in vitro characterization, we suggest that incomplete penetrant variants are only deleterious if a yet unknown interacting partner of ABCC6 is mutated simultaneously. The low penetrance of these variants should be contemplated in genetic counseling.
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Affiliation(s)
- Flora Szeri
- Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College, and The PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA,Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary,Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Agnes Miko
- MTA-SE Lendület Nephrogenetic Laboratory, Budapest, Hungary,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Nastassia Navasiolava
- PXE Consultation Center, MAGEC Nord Reference Center for Rare Skin Diseases, Angers University Hospital, Angers, France
| | - Ambrus Kaposi
- MTA-SE Lendület Nephrogenetic Laboratory, Budapest, Hungary,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Shana Verschuere
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Beatrix Molnar
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Qiaoli Li
- Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College, and The PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College, and The PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College, and The PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Nord Reference Center for Rare Skin Diseases, Angers University Hospital, Angers, France
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy,Interuniversity Consortium for Biotechnologies (CIB), Italy
| | | | - Kalman Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Budapest, Hungary,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Tamas Aranyi
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary,Department of Molecular Biology, Semmelweis University, Budapest, Hungary.,Corresponding author:
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6
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Targeting ABCC6 in Mesenchymal Stem Cells: Impairment of Mature Adipocyte Lipid Homeostasis. Int J Mol Sci 2022; 23:ijms23169218. [PMID: 36012482 PMCID: PMC9409192 DOI: 10.3390/ijms23169218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/12/2022] [Accepted: 08/14/2022] [Indexed: 11/16/2022] Open
Abstract
Mutations in ABCC6, an ATP-binding cassette transporter with a so far unknown substrate mainly expressed in the liver and kidney, cause pseudoxanthoma elasticum (PXE). Symptoms of PXE in patients originate from the calcification of elastic fibers in the skin, eye, and vessels. Previous studies suggested an involvement of ABCC6 in cholesterol and lipid homeostasis. The intention of this study was to examine the influence of ABCC6 deficiency during adipogenic differentiation of human bone marrow-derived stem cells (hMSCs). Induction of adipogenic differentiation goes along with significantly elevated ABCC6 gene expression in mature adipocytes. We generated an ABCC6-deficient cell culture model using clustered regulatory interspaced short palindromic repeat Cas9 (CRISPR–Cas9) system to clarify the role of ABCC6 in lipid homeostasis. The lack of ABCC6 in hMSCs does not influence gene expression of differentiation markers in adipogenesis but results in a decreased triglyceride content in cell culture medium. Protein and gene expression analysis of mature ABCC6-deficient adipocytes showed diminished intra- and extra-cellular lipolysis, release of lipids, and fatty acid neogenesis. Therefore, our results demonstrate impaired lipid trafficking in adipocytes due to ABCC6 deficiency, highlighting adipose tissue and peripheral lipid metabolism as a relevant target for uncovering systemic PXE pathogenesis.
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7
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Szeri F, Corradi V, Niaziorimi F, Donnelly S, Conseil G, Cole SPC, Tieleman DP, van de Wetering K. Mutagenic Analysis of the Putative ABCC6 Substrate-Binding Cavity Using a New Homology Model. Int J Mol Sci 2021; 22:ijms22136910. [PMID: 34199119 PMCID: PMC8267652 DOI: 10.3390/ijms22136910] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/19/2021] [Accepted: 06/23/2021] [Indexed: 12/16/2022] Open
Abstract
Inactivating mutations in ABCC6 underlie the rare hereditary mineralization disorder pseudoxanthoma elasticum. ABCC6 is an ATP-binding cassette (ABC) integral membrane protein that mediates the release of ATP from hepatocytes into the bloodstream. The released ATP is extracellularly converted into pyrophosphate, a key mineralization inhibitor. Although ABCC6 is firmly linked to cellular ATP release, the molecular details of ABCC6-mediated ATP release remain elusive. Most of the currently available data support the hypothesis that ABCC6 is an ATP-dependent ATP efflux pump, an un-precedented function for an ABC transporter. This hypothesis implies the presence of an ATP-binding site in the substrate-binding cavity of ABCC6. We performed an extensive mutagenesis study using a new homology model based on recently published structures of its close homolog, bovine Abcc1, to characterize the substrate-binding cavity of ABCC6. Leukotriene C4 (LTC4), is a high-affinity substrate of ABCC1. We mutagenized fourteen amino acid residues in the rat ortholog of ABCC6, rAbcc6, that corresponded to the residues in ABCC1 found in the LTC4 binding cavity. Our functional characterization revealed that most of the amino acids in rAbcc6 corresponding to those found in the LTC4 binding pocket in bovine Abcc1 are not critical for ATP efflux. We conclude that the putative ATP binding site in the substrate-binding cavity of ABCC6/rAbcc6 is distinct from the bovine Abcc1 LTC4-binding site.
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Affiliation(s)
- Flora Szeri
- Department of Dermatology and Cutaneous Biology and PXE Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA 19107, USA; (F.S.); (F.N.); (S.D.)
- Research Centre for Natural Sciences, Institute of Enzymology, 1117 Budapest, Hungary
| | - Valentina Corradi
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, Calgary, AB T2N 1N4, Canada; (V.C.); (D.P.T.)
| | - Fatemeh Niaziorimi
- Department of Dermatology and Cutaneous Biology and PXE Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA 19107, USA; (F.S.); (F.N.); (S.D.)
| | - Sylvia Donnelly
- Department of Dermatology and Cutaneous Biology and PXE Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA 19107, USA; (F.S.); (F.N.); (S.D.)
| | - Gwenaëlle Conseil
- Department of Pathology and Molecular Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada; (G.C.); (S.P.C.C.)
| | - Susan P. C. Cole
- Department of Pathology and Molecular Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada; (G.C.); (S.P.C.C.)
| | - D. Peter Tieleman
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, Calgary, AB T2N 1N4, Canada; (V.C.); (D.P.T.)
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology and PXE Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA 19107, USA; (F.S.); (F.N.); (S.D.)
- Correspondence: ; Tel.: +1-(215)-503-5701
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8
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Shimada BK, Pomozi V, Zoll J, Kuo S, Martin L, Le Saux O. ABCC6, Pyrophosphate and Ectopic Calcification: Therapeutic Solutions. Int J Mol Sci 2021; 22:ijms22094555. [PMID: 33925341 PMCID: PMC8123679 DOI: 10.3390/ijms22094555] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Pathological (ectopic) mineralization of soft tissues occurs during aging, in several common conditions such as diabetes, hypercholesterolemia, and renal failure and in certain genetic disorders. Pseudoxanthoma elasticum (PXE), a multi-organ disease affecting dermal, ocular, and cardiovascular tissues, is a model for ectopic mineralization disorders. ABCC6 dysfunction is the primary cause of PXE, but also some cases of generalized arterial calcification of infancy (GACI). ABCC6 deficiency in mice underlies an inducible dystrophic cardiac calcification phenotype (DCC). These calcification diseases are part of a spectrum of mineralization disorders that also includes Calcification of Joints and Arteries (CALJA). Since the identification of ABCC6 as the “PXE gene” and the development of several animal models (mice, rat, and zebrafish), there has been significant progress in our understanding of the molecular genetics, the clinical phenotypes, and pathogenesis of these diseases, which share similarities with more common conditions with abnormal calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into inorganic pyrophosphate (PPi) and adenosine by the ectonucleotidases NPP1 and CD73 (NT5E). PPi is a potent endogenous inhibitor of calcification, whereas adenosine indirectly contributes to calcification inhibition by suppressing the synthesis of tissue non-specific alkaline phosphatase (TNAP). At present, therapies only exist to alleviate symptoms for both PXE and GACI; however, extensive studies have resulted in several novel approaches to treating PXE and GACI. This review seeks to summarize the role of ABCC6 in ectopic calcification in PXE and other calcification disorders, and discuss therapeutic strategies targeting various proteins in the pathway (ABCC6, NPP1, and TNAP) and direct inhibition of calcification via supplementation by various compounds.
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Affiliation(s)
- Briana K Shimada
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Sheree Kuo
- Department of Pediatrics, Kapi'olani Medical Center for Women and Children, University of Hawaii, Honolulu, HI 96826, USA
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Reference Center for Rare Skin Diseases, Angers University Hospital, 49100 Angers, France
- BNMI, CNRS 6214/INSERM 1083, University Bretagne-Loire, 49100 Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
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9
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Szeri F, Niaziorimi F, Donnelly S, Orndorff J, van de Wetering K. Generation of fully functional fluorescent fusion proteins to gain insights into ABCC6 biology. FEBS Lett 2021; 595:799-810. [PMID: 33058196 PMCID: PMC7987643 DOI: 10.1002/1873-3468.13957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/04/2020] [Accepted: 09/29/2020] [Indexed: 12/18/2022]
Abstract
ABCC6 mediates release of ATP from hepatocytes into the blood. Extracellularly, ATP is converted into the mineralization inhibitor pyrophosphate. Consequently, inactivating mutations in ABCC6 give low plasma pyrophosphate and underlie the ectopic mineralization disorder pseudoxanthoma elasticum. How ABCC6 mediates cellular ATP release is still unknown. Fluorescent ABCC6 fusion proteins would allow mechanistic studies, but fluorophores attached to the ABCC6 N- or C-terminus result in intracellular retention and degradation. Here we describe that intramolecular introduction of fluorophores yields fully functional ABCC6 fusion proteins. A corresponding ABCC6 variant in which the catalytic glutamate of the second nucleotide binding domain was mutated, correctly routed to the plasma membrane but was inactive. Finally, N-terminal His10 or FLAG tags did not affect activity of the fusion proteins, allowing their purification for biochemical characterization.
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Affiliation(s)
- Flora Szeri
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 19107, Philadelphia (PA), USA
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary (current address)
| | - Fatemeh Niaziorimi
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 19107, Philadelphia (PA), USA
| | - Sylvia Donnelly
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 19107, Philadelphia (PA), USA
| | - Joseph Orndorff
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 19107, Philadelphia (PA), USA
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 19107, Philadelphia (PA), USA
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10
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Veiga-Lopez A, Sethuraman V, Navasiolava N, Makela B, Olomu I, Long R, van de Wetering K, Martin L, Aranyi T, Szeri F. Plasma Inorganic Pyrophosphate Deficiency Links Multiparity to Cardiovascular Disease Risk. Front Cell Dev Biol 2020; 8:573727. [PMID: 33363139 PMCID: PMC7755719 DOI: 10.3389/fcell.2020.573727] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/18/2020] [Indexed: 12/17/2022] Open
Abstract
Epidemiological studies indicate that elevated alkaline phosphatase activity is associated with increased cardiovascular disease risk. Other epidemiological data demonstrate that mothers giving multiple childbirths (multipara) are also at increased risk of developing late-onset cardiovascular disease. We hypothesized that these two associations stem from a common cause, the insufficient plasma level of the ectopic mineralization inhibitor inorganic pyrophosphate, which is a substrate of alkaline phosphatase. As alkaline phosphatase activity is elevated in pregnancy, we hypothesized that pyrophosphate concentrations decrease gestationally, potentially leading to increased maternal vascular calcification and cardiovascular disease risk in multipara. We investigated plasma pyrophosphate kinetics pre- and postpartum in sheep and at term in humans and demonstrated its shortage in pregnancy, mirroring alkaline phosphatase activity. Next, we tested whether multiparity is associated with increased vascular calcification in pseudoxanthoma elasticum patients, characterized by low intrinsic plasma pyrophosphate levels. We demonstrated that these patients had increased vascular calcification when they give birth multiple times. We propose that transient shortages of pyrophosphate during repeated pregnancies might contribute to vascular calcification and multiparity-associated cardiovascular disease risk threatening hundreds of millions of healthy women worldwide. Future trials are needed to assess if gestational pyrophosphate supplementation might be a suitable prophylactic treatment to mitigate maternal cardiovascular disease risk in multiparous women.
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Affiliation(s)
- Almudena Veiga-Lopez
- Department of Pathology, The University of Illinois at Chicago, Chicago, IL, United States.,Department of Animal Science, Michigan State University, East Lansing, MI, United States
| | - Visalakshi Sethuraman
- Department of Pediatrics and Human Development, Michigan State University, Lansing, MI, United States.,Department of Pediatrics, Texas Tech University Health Sciences Center, Odessa, TX, United States
| | | | - Barbara Makela
- Department of Animal Science, Michigan State University, East Lansing, MI, United States
| | - Isoken Olomu
- Department of Pediatrics and Human Development, Michigan State University, Lansing, MI, United States
| | - Robert Long
- Department of Obstetrics and Gynecology, Sparrow Hospital, Lansing, MI, United States
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, United States
| | - Ludovic Martin
- Department of Pediatrics, Texas Tech University Health Sciences Center, Odessa, TX, United States
| | - Tamas Aranyi
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary.,Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Flora Szeri
- Department of Dermatology and Cutaneous Biology, PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, United States.,Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,Department of Biochemistry, Semmelweis University, Budapest, Hungary
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11
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Kozák E, Szikora B, Iliás A, Jani PK, Hegyi Z, Matula Z, Dedinszki D, Tőkési N, Fülöp K, Pomozi V, Várady G, Bakos É, Tusnády GE, Kacskovics I, Váradi A. Creation of the first monoclonal antibody recognizing an extracellular epitope of hABCC6. FEBS Lett 2020; 595:789-798. [PMID: 33159684 DOI: 10.1002/1873-3468.13991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/12/2020] [Accepted: 10/16/2020] [Indexed: 11/11/2022]
Abstract
Mutations in the ABCC6 gene result in calcification diseases such as pseudoxanthoma elasticum or Generalized Arterial Calcification of Infancy. Generation of antibodies recognizing an extracellular (EC) epitope of ABCC6 has been hampered by the short EC segments of the protein. To overcome this limitation, we immunized bovine FcRn transgenic mice exhibiting an augmented humoral immune response with Human Embryonic Kidney 293 cells cells expressing human ABCC6 (hABCC6). We obtained a monoclonal antibody recognizing an EC epitope of hABCC6 that we named mEChC6. Limited proteolysis revealed that the epitope is within a loop in the N-terminal half of ABCC6 and probably spans amino acids 338-347. mEChC6 recognizes hABCC6 in the liver of hABCC6 transgenic mice, verifying both specificity and EC binding to intact hepatocytes.
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Affiliation(s)
- Eszter Kozák
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary.,Department of Immunology, Eötvös Loránd University of Budapest, Hungary
| | - Bence Szikora
- Department of Immunology, Eötvös Loránd University of Budapest, Hungary.,ImmunoGenes Ltd., Budakeszi, Hungary
| | - Attila Iliás
- Department of Immunology, Eötvös Loránd University of Budapest, Hungary
| | | | - Zoltán Hegyi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Zsolt Matula
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Dóra Dedinszki
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Natália Tőkési
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Krisztina Fülöp
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Viola Pomozi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - György Várady
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Éva Bakos
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Gabor E Tusnády
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Imre Kacskovics
- Department of Immunology, Eötvös Loránd University of Budapest, Hungary.,ImmunoGenes Ltd., Budakeszi, Hungary
| | - Andras Váradi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
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12
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Verschuere S, Van Gils M, Nollet L, Vanakker OM. From membrane to mineralization: the curious case of the ABCC6 transporter. FEBS Lett 2020; 594:4109-4133. [PMID: 33131056 DOI: 10.1002/1873-3468.13981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/12/2020] [Accepted: 10/16/2020] [Indexed: 12/13/2022]
Abstract
ATP-binding cassette subfamily C member 6 gene/protein (ABCC6) is an ATP-dependent transmembrane transporter predominantly expressed in the liver and the kidney. ABCC6 first came to attention in human medicine when it was discovered in 2000 that mutations in its encoding gene, ABCC6, caused the autosomal recessive multisystemic mineralization disease pseudoxanthoma elasticum (PXE). Since then, the physiological and pathological roles of ABCC6 have been the subject of intense research. In the last 20 years, significant findings have clarified ABCC6 structure as well as its physiological role in mineralization homeostasis in humans and animal models. Yet, several facets of ABCC6 biology remain currently incompletely understood, ranging from the precise nature of its substrate(s) to the increasingly complex molecular genetics. Nonetheless, advances in our understanding of pathophysiological mechanisms causing mineralization lead to several treatment options being suggested or already tested in pilot clinical trials for ABCC6 deficiency. This review highlights current knowledge of ABCC6 and the challenges ahead, particularly the attempts to translate basic science into clinical practice.
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Affiliation(s)
- Shana Verschuere
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Matthias Van Gils
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Lukas Nollet
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Olivier M Vanakker
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
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13
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Ostuni A, Carmosino M, Miglionico R, Abruzzese V, Martinelli F, Russo D, Laurenzana I, Petillo A, Bisaccia F. Inhibition of ABCC6 Transporter Modifies Cytoskeleton and Reduces Motility of HepG2 Cells via Purinergic Pathway. Cells 2020; 9:cells9061410. [PMID: 32517079 PMCID: PMC7349786 DOI: 10.3390/cells9061410] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 12/22/2022] Open
Abstract
ABCC6, belonging to sub-family C of ATP-binding cassette transporter, is an ATP-dependent transporter mainly present in the basolateral plasma membrane of hepatic and kidney cells. Although the substrates transported are still uncertain, ABCC6 has been shown to promote ATP release. The extracellular ATP and its derivatives di- and mono-nucleotides and adenosine by acting on specific receptors activate the so-called purinergic pathway, which in turn controls relevant cellular functions such as cell immunity, inflammation, and cancer. Here, we analyzed the effect of Abcc6 knockdown and probenecid-induced ABCC6 inhibition on cell cycle, cytoskeleton, and motility of HepG2 cells. Gene and protein expression were evaluated by quantitative Reverse Transcription PCR (RT-qPCR) and western blot, respectively. Cellular cycle analysis was evaluated by flow cytometry. Actin cytoskeleton dynamics was evaluated by laser confocal microscopy using fluorophore-conjugated phalloidin. Cell motility was analyzed by in vitro wound-healing migration assay. Cell migration is reduced both in Abcc6 knockdown HepG2 cells and in probenecid treated HepG2 cells by interfering with the extracellular reserve of ATP. Therefore, ABCC6 could contribute to cytoskeleton rearrangements and cell motility through purinergic signaling. Altogether, our findings shed light on a new role of the ABCC6 transporter in HepG2 cells and suggest that its inhibitor/s could be considered potential anti-metastatic drugs.
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Affiliation(s)
- Angela Ostuni
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
- Correspondence: (A.O.); (F.B.); Tel.: +39-0971-205453 (A.O.); Tel.: +39-0971-205462 (F.B.)
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Rocchina Miglionico
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Vittorio Abruzzese
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Fabio Martinelli
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Daniela Russo
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Ilaria Laurenzana
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture, Italy;
| | - Agata Petillo
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
| | - Faustino Bisaccia
- Department of Sciences, University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (R.M.); (V.A.); (F.M.); (D.R.); (A.P.)
- Correspondence: (A.O.); (F.B.); Tel.: +39-0971-205453 (A.O.); Tel.: +39-0971-205462 (F.B.)
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14
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Pseudoxanthoma Elasticum, Kidney Stones and Pyrophosphate: From a Rare Disease to Urolithiasis and Vascular Calcifications. Int J Mol Sci 2019; 20:ijms20246353. [PMID: 31861118 PMCID: PMC6940945 DOI: 10.3390/ijms20246353] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/09/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022] Open
Abstract
Pseudoxanthoma elasticum is a rare disease mainly due to ABCC6 gene mutations and characterized by ectopic biomineralization and fragmentation of elastic fibers resulting in skin, cardiovascular and retinal calcifications. It has been recently described that pyrophosphate (a calcification inhibitor) deficiency could be the main cause of ectopic calcifications in this disease and in other genetic disorders associated to mutations of ENPP1 or CD73. Patients affected by Pseudoxanthoma Elasticum seem also prone to develop kidney stones originating from papillary calcifications named Randall’s plaque, and to a lesser extent may be affected by nephrocalcinosis. In this narrative review, we summarize some recent discoveries relative to the pathophysiology of this mendelian disease responsible for both cardiovascular and renal papillary calcifications, and we discuss the potential implications of pyrophosphate deficiency as a promoter of vascular calcifications in kidney stone formers and in patients affected by chronic kidney disease.
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15
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Pomozi V, Julian CB, Zoll J, Pham K, Kuo S, Tőkési N, Martin L, Váradi A, Le Saux O. Dietary Pyrophosphate Modulates Calcification in a Mouse Model of Pseudoxanthoma Elasticum: Implication for Treatment of Patients. J Invest Dermatol 2018; 139:1082-1088. [PMID: 30468740 DOI: 10.1016/j.jid.2018.10.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/11/2018] [Accepted: 10/25/2018] [Indexed: 12/15/2022]
Abstract
Pseudoxanthoma elasticum is a heritable disease caused by ABCC6 deficiency. Patients develop ectopic calcification in skin, eyes, and vascular tissues. ABCC6, primarily found in liver and kidneys, mediates the cellular efflux of ATP, which is rapidly converted into inorganic pyrophosphate (PPi), a potent inhibitor of calcification. Pseudoxanthoma elasticum patients and Abcc6-/- mice display reduced PPi levels in plasma and peripheral tissues. Pseudoxanthoma elasticum is currently incurable, although some palliative treatments exist. In recent years, we have successfully developed therapeutic methodologies to compensate the PPi deficit in animal models and humans. Here, we inadvertently discovered that modulating dietary PPi can also be an effective approach to reducing calcification in Abcc6-/- mice. Our findings were prompted by a change in institutional rodent diet. The new chow was enriched in PPi, which increased plasma PPi, and significantly reduced mineralization in Abcc6-/- mice. We also found that dietary PPi is readily absorbed in humans. Our results suggest that the consumption of food naturally or artificially enriched in PPi represents a possible intervention to mitigate calcification progression in pseudoxanthoma elasticum, that dietary preferences of patients may explain pseudoxanthoma elasticum heterogeneous manifestations, and that animal chow has the potential to influence data reproducibility.
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Affiliation(s)
- Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Charnelle B Julian
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Kevin Pham
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Sheree Kuo
- Department of Pediatrics Kapi'olani Medical Center for Women and Children and University of Hawaii, John A. Burns School of Medicine, Honolulu, Hawaii, USA
| | - Natália Tőkési
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ludovic Martin
- Université d'Angers, MitoVasc, Le Centre National de la Recherche Scientifique 6015/Institut National de la Santé et de la Recherche Médicale 1083, Angers, France; Centre Hospitalier Universitaire d'Angers, Centre de Référence PXE, Reference Centre for Genetic Dermatologic Diseases, Nord, Angers, France
| | - András Váradi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
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16
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Borst P, Váradi A, van de Wetering K. PXE, a Mysterious Inborn Error Clarified. Trends Biochem Sci 2018; 44:125-140. [PMID: 30446375 DOI: 10.1016/j.tibs.2018.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/07/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022]
Abstract
Ever since Garrod deduced the existence of inborn errors in 1901, a vast array of metabolic diseases has been identified and characterized in molecular terms. In 2018 it is difficult to imagine that there is any uncharted backyard left in the metabolic disease landscape. Nevertheless, it took until 2013 to identify the cause of a relatively frequent inborn error, pseudoxanthoma elasticum (PXE), a disorder resulting in aberrant calcification. The mechanism found was not only biochemically interesting but also points to possible new treatments for PXE, a disease that has remained untreatable. In this review we sketch the tortuous road that led to the biochemical understanding of PXE and to new ideas for treatment. We also discuss some of the controversies still haunting the field.
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Affiliation(s)
- Piet Borst
- Division of Oncogenetics, The Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands.
| | - András Váradi
- Institute of Enzymology, Research Center for Natural Sciences (RCNS), Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology and PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA 19107, USA
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17
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Williams EG, Wu Y, Wolski W, Kim JY, Lan J, Hasan M, Halter C, Jha P, Ryu D, Auwerx J, Aebersold R. Quantifying and Localizing the Mitochondrial Proteome Across Five Tissues in A Mouse Population. Mol Cell Proteomics 2018; 17:1766-1777. [PMID: 29945935 DOI: 10.1074/mcp.ra118.000554] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/17/2018] [Indexed: 12/12/2022] Open
Abstract
We have used SWATH mass spectrometry to quantify 3648 proteins across 76 proteomes collected from genetically diverse BXD mouse strains in two fractions (mitochondria and total cell) from five tissues: liver, quadriceps, heart, brain, and brown adipose (BAT). Across tissues, expression covariation between genes' proteins and transcripts-measured in the same individuals-broadly aligned. Covariation was however far stronger in certain subsets than others: only 8% of transcripts in the lowest expression and variance quintile covaried with their protein, in contrast to 65% of transcripts in the highest quintiles. Key functional differences among the 3648 genes were also observed across tissues, with electron transport chain (ETC) genes particularly investigated. ETC complex proteins covary and form strong gene networks according to tissue, but their equivalent transcripts do not. Certain physiological consequences, such as the depletion of ATP synthase in BAT, are thus obscured in transcript data. Lastly, we compared the quantitative proteomic measurements between the total cell and mitochondrial fractions for the five tissues. The resulting enrichment score highlighted several hundred proteins which were strongly enriched in mitochondria, which included several dozen proteins were not reported in literature to be mitochondrially localized. Four of these candidates were selected for biochemical validation, where we found MTAP, SOAT2, and IMPDH2 to be localized inside the mitochondria, whereas ABCC6 was in the mitochondria-associated membrane. These findings demonstrate the synergies of a multi-omics approach to study complex metabolic processes, and this provides a resource for further discovery and analysis of proteoforms, modified proteins, and protein localization.
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Affiliation(s)
- Evan G Williams
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland.,§Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Yibo Wu
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland.,**Current address: RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho Tsurumi-ku Yokohama City, Kanagawa, 230-0045, Japan
| | - Witold Wolski
- ¶Functional Genomics Center Zurich, ETH Zurich, Zurich CH-8057, Switzerland
| | - Jun Yong Kim
- §Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Jiayi Lan
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland
| | - Moaraj Hasan
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland
| | - Christian Halter
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland
| | - Pooja Jha
- §Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Dongryeol Ryu
- §Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.,‡‡Current address: Healthy Aging-Korean Medical Research Center, Pusan National University, School of Korean Medicine, Yangsan 50612, Republic of Korea
| | - Johan Auwerx
- §Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland;
| | - Ruedi Aebersold
- From the ‡Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland; .,‖Faculty of Science, University of Zurich, Zurich CH-8057, Switzerland
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18
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Kauffenstein G, Yegutkin GG, Khiati S, Pomozi V, Le Saux O, Leftheriotis G, Lenaers G, Henrion D, Martin L. Alteration of Extracellular Nucleotide Metabolism in Pseudoxanthoma Elasticum. J Invest Dermatol 2018; 138:1862-1870. [PMID: 29501384 DOI: 10.1016/j.jid.2018.02.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 02/02/2018] [Accepted: 02/15/2018] [Indexed: 01/06/2023]
Abstract
Pseudoxanthoma elasticum (PXE) is a rare genetic condition primarily caused by hepatic ABCC6 transporter dysfunction. Most clinical manifestations of PXE are due to premature calcification of elastic fibers. However, the vascular impact of PXE is pleiotropic and remains ill defined. ABCC6 expression has recently been associated with cellular nucleotide export. We studied the impact of ABCC6 deficiency on blood levels of adenosine triphosphate and related metabolites and on soluble nucleotidase activities in PXE patients and Abcc6-/- mice. In addition, we investigated the expression of genes encoding ectocellular purinergic signaling proteins in mouse liver and aorta. Plasma adenosine triphosphate and pyrophosphate levels were significantly reduced in PXE patients and in Abcc6-/- mice, whereas adenosine concentration was not modified. Moreover, 5'-nucleotidase/CD73 activity was increased in the serum of PXE patients and Abcc6-/- mice. Consistent with alterations of purinergic signaling, the expression of genes involved in purine and phosphate transport/metabolism was dramatically modified in Abcc6-/- mouse aorta, with much less impact on the liver. ABCC6 deficiency causes impaired vascular homeostasis and tissue perfusion. Our findings suggest that these alterations are linked to changes in extracellular nucleotide metabolism that are remote from the liver. This opens new perspectives for the understanding of PXE pathophysiology.
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Affiliation(s)
- Gilles Kauffenstein
- MITOVASC-UMR CNRS 6015 INSERM U1083, Angers University, France; University Hospital of Angers, Angers, France.
| | - Gennady G Yegutkin
- Department of Microbiology and Immunology, MediCity Research Laboratory, University of Turku, Finland
| | - Salim Khiati
- MITOVASC-UMR CNRS 6015 INSERM U1083, Angers University, France
| | - Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | | | - Guy Lenaers
- MITOVASC-UMR CNRS 6015 INSERM U1083, Angers University, France
| | - Daniel Henrion
- MITOVASC-UMR CNRS 6015 INSERM U1083, Angers University, France
| | - Ludovic Martin
- MITOVASC-UMR CNRS 6015 INSERM U1083, Angers University, France; University Hospital of Angers, Angers, France
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19
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Váradi A, Fülöp K, Arányi T, Szeri F. Tissue-nonspecific alkaline phosphatase: a promising target for pseudoxanthoma elasticum therapy. ANNALS OF TRANSLATIONAL MEDICINE 2017; 5:489. [PMID: 29299451 DOI: 10.21037/atm.2017.10.01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Krisztina Fülöp
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás Arányi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Flóra Szeri
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
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20
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Favre G, Laurain A, Aranyi T, Szeri F, Fulop K, Le Saux O, Duranton C, Kauffenstein G, Martin L, Lefthériotis G. The ABCC6 Transporter: A New Player in Biomineralization. Int J Mol Sci 2017; 18:ijms18091941. [PMID: 28891970 PMCID: PMC5618590 DOI: 10.3390/ijms18091941] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/02/2017] [Accepted: 09/05/2017] [Indexed: 12/16/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is an inherited metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. Since the first description of the disease in 1896, alleging a disease involving the elastic fibers, the concept evolved with the further discoveries of the pivotal role of ectopic mineralization that is preponderant in the elastin-rich tissues of the skin, eyes and blood vessel walls. After discovery of the causative gene of the disease in 2000, the function of the ABCC6 protein remains elusive. More than 300 mutations have been now reported and the concept of a dermal disease has progressively evolved toward a metabolic disorder resulting from the remote effects caused by lack of a circulating anti-mineralization factor. Very recently, evidence has accumulated that this anti-mineralizing factor is inorganic pyrophosphate (PPi). This leads to decreased PPi/Pi (inorganic phosphate) ratio that results from the lack of extracellular ATP release by hepatocytes and probably renal cells harboring the mutant ABCC6 protein. However, the mechanism by which ABCC6 dysfunction causes diminished ATP release remains an enigma. Studies of other ABC transporters, such as ABCC7 or ABCC1 could help our understanding of what ABCC6 exact function is. Data and a hypothesis on the possible roles of ABCC6 in acquired metabolic diseases are also discussed.
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Affiliation(s)
- Guillaume Favre
- FINSERM, U 1081, Aging and Diabetes Team, Institute for Research on Cancer and Aging of Nice (IRCAN), 06107 Nice, France.
- CNRS, UMR7284, Institute for Research on Cancer and Aging of Nice (IRCAN), 06107 Nice, France.
- Faculty of Medicine, University of Nice-Sophia Antipolis, 06107 Nice, France.
- Nephrology Department, University Hospital, 06107 Nice, France.
| | - Audrey Laurain
- Nephrology Department, University Hospital, 06107 Nice, France.
| | - Tamas Aranyi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.
| | - Flora Szeri
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.
| | - Krisztina Fulop
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.
| | - Olivier Le Saux
- Department Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA.
| | - Christophe Duranton
- Laboratory of Physiology and Molecular Medicine (LP2M) UMR CNRS 7073, 06107 Nice, France.
| | - Gilles Kauffenstein
- UMR CNRS 6015-Inserm 1083, School of Medicine, Bretagne Loire University, 49045 Angers, France.
- PXE Health and Research Center, University Hospital of Angers, 49045 Angers, France.
| | - Ludovic Martin
- UMR CNRS 6015-Inserm 1083, School of Medicine, Bretagne Loire University, 49045 Angers, France.
- PXE Health and Research Center, University Hospital of Angers, 49045 Angers, France.
| | - Georges Lefthériotis
- Faculty of Medicine, University of Nice-Sophia Antipolis, 06107 Nice, France.
- Laboratory of Physiology and Molecular Medicine (LP2M) UMR CNRS 7073, 06107 Nice, France.
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21
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Ziegler SG, Ferreira CR, MacFarlane EG, Riddle RC, Tomlinson RE, Chew EY, Martin L, Ma CT, Sergienko E, Pinkerton AB, Millán JL, Gahl WA, Dietz HC. Ectopic calcification in pseudoxanthoma elasticum responds to inhibition of tissue-nonspecific alkaline phosphatase. Sci Transl Med 2017; 9:eaal1669. [PMID: 28592560 PMCID: PMC5606141 DOI: 10.1126/scitranslmed.aal1669] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/10/2017] [Accepted: 04/25/2017] [Indexed: 12/26/2022]
Abstract
Biallelic mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a disease characterized by calcification in the skin, eyes, and blood vessels. The function of ATP-binding cassette C6 (ABCC6) and the pathogenesis of PXE remain unclear. We used mouse models and patient fibroblasts to demonstrate genetic interaction and shared biochemical and cellular mechanisms underlying ectopic calcification in PXE and related disorders caused by defined perturbations in extracellular adenosine 5'-triphosphate catabolism. Under osteogenic culture conditions, ABCC6 mutant cells calcified, suggesting a provoked cell-autonomous defect. Using a conditional Abcc6 knockout mouse model, we excluded the prevailing pathogenic hypothesis that singularly invokes failure of hepatic secretion of an endocrine inhibitor of calcification. Instead, deficiency of Abcc6 in both local and distant cells was necessary to achieve the early onset and penetrant ectopic calcification observed upon constitutive gene targeting. ABCC6 mutant cells additionally had increased expression and activity of tissue-nonspecific alkaline phosphatase (TNAP), an enzyme that degrades pyrophosphate, a major inhibitor of calcification. A selective and orally bioavailable TNAP inhibitor prevented calcification in ABCC6 mutant cells in vitro and attenuated both the development and progression of calcification in Abcc6-/- mice in vivo, without the deleterious effects on bone associated with other proposed treatment strategies.
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Affiliation(s)
- Shira G Ziegler
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Carlos R Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Elena Gallo MacFarlane
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Baltimore Veterans Administrations Medical Center, Baltimore, MD 21201, USA
| | - Ryan E Tomlinson
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Emily Y Chew
- National Eye Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Ludovic Martin
- PXE Reference Center and MitoVasc Institute, Angers University Hospital, Angers, France
| | - Chen-Ting Ma
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Eduard Sergienko
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | | | - José Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Harry C Dietz
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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22
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Paththinige CS, Sirisena ND, Dissanayake V. Genetic determinants of inherited susceptibility to hypercholesterolemia - a comprehensive literature review. Lipids Health Dis 2017; 16:103. [PMID: 28577571 PMCID: PMC5457620 DOI: 10.1186/s12944-017-0488-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/17/2017] [Indexed: 02/08/2023] Open
Abstract
Hypercholesterolemia is a strong determinant of mortality and morbidity associated with cardiovascular diseases and a major contributor to the global disease burden. Mutations in four genes (LDLR, APOB, PCSK9 and LDLRAP1) account for the majority of cases with familial hypercholesterolemia. However, a substantial proportion of adults with hypercholesterolemia do not have a mutation in any of these four genes. This indicates the probability of having other genes with a causative or contributory role in the pathogenesis of hypercholesterolemia and suggests a polygenic inheritance of this condition. Here in, we review the recent evidence of association of the genetic variants with hypercholesterolemia and the three lipid traits; total cholesterol (TC), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C), their biological pathways and the associated pathogenetic mechanisms. Nearly 80 genes involved in lipid metabolism (encoding structural components of lipoproteins, lipoprotein receptors and related proteins, enzymes, lipid transporters, lipid transfer proteins, and activators or inhibitors of protein function and gene transcription) with single nucleotide variants (SNVs) that are recognized to be associated with hypercholesterolemia and serum lipid traits in genome-wide association studies and candidate gene studies were identified. In addition, genome-wide association studies in different populations have identified SNVs associated with TC, HDL-C and LDL-C in nearly 120 genes within or in the vicinity of the genes that are not known to be involved in lipid metabolism. Over 90% of the SNVs in both these groups are located outside the coding regions of the genes. These findings indicates that there might be a considerable number of unrecognized processes and mechanisms of lipid homeostasis, which when disrupted, would lead to hypercholesterolemia. Knowledge of these molecular pathways will enable the discovery of novel treatment and preventive methods as well as identify the biochemical and molecular markers for the risk prediction and early detection of this common, yet potentially debilitating condition.
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Affiliation(s)
- C S Paththinige
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, 00800, Sri Lanka.
| | - N D Sirisena
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, 00800, Sri Lanka
| | - Vhw Dissanayake
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, 00800, Sri Lanka
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23
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Abstract
Pseudoxanthoma elasticum (PXE) is a genetic metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. The lack of functional ABCC6 protein leads to ectopic mineralization that is most apparent in the elastic tissues of the skin, eyes and blood vessels. The clinical prevalence of PXE has been estimated at between 1 per 100,000 and 1 per 25,000, with slight female predominance. The first clinical sign of PXE is almost always small yellow papules on the nape and sides of the neck and in flexural areas. The papules coalesce, and the skin becomes loose and wrinkled. The mid-dermal elastic fibers are short, fragmented, clumped and calcified. Dystrophic calcification of Bruch's membrane, revealed by angioid streaks, may trigger choroidal neovascularization and, ultimately, loss of central vision and blindness in late-stage disease. Lesions in small and medium-sized artery walls may result in intermittent claudication and peripheral artery disease. Cardiac complications (myocardial infarction, angina pectoris) are thought to be relatively rare but merit thorough investigation. Ischemic strokes have been reported. PXE is a metabolic disease in which circulating levels of an anti-mineralization factor are low. There is good evidence to suggest that the factor is inorganic pyrophosphate (PPi), and that the circulating low levels of PPi and decreased PPi/Pi ratio result from the lack of ATP release by hepatocytes harboring the mutant ABCC6 protein. However, the substrate(s) bound, transported or modulated by the ABCC6 protein remain unknown. More than 300 sequence variants of the ABCC6 gene have been identified. There is no cure for PXE; the main symptomatic treatments are vascular endothelial growth factor inhibitor therapy (for ophthalmic manifestations), lifestyle, lipid-lowering and dietary measures (for reducing vascular risk factors), and vascular surgery (for severe cardiovascular manifestations). Future treatment options may include gene therapy/editing and pharmacologic chaperone therapy.
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Affiliation(s)
- Dominique P Germain
- Division of Medical Genetics, University of Versailles - Saint Quentin en Yvelines, Paris-Saclay University, 2 avenue de la source de la Bièvre, F-78180, Montigny, France.
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Thakkar N, Slizgi JR, Brouwer KLR. Effect of Liver Disease on Hepatic Transporter Expression and Function. J Pharm Sci 2017; 106:2282-2294. [PMID: 28465155 DOI: 10.1016/j.xphs.2017.04.053] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 12/27/2022]
Abstract
Liver disease can alter the disposition of xenobiotics and endogenous substances. Regulatory agencies such as the Food and Drug Administration and the European Medicines Evaluation Agency recommend, if possible, studying the effect of liver disease on drugs under development to guide specific dose recommendations in these patients. Although extensive research has been conducted to characterize the effect of liver disease on drug-metabolizing enzymes, emerging data have implicated that the expression and function of hepatobiliary transport proteins also are altered in liver disease. This review summarizes recent developments in the field, which may have implications for understanding altered disposition, safety, and efficacy of new and existing drugs. A brief review of liver physiology and hepatic transporter localization/function is provided. Then, the expression and function of hepatic transporters in cholestasis, hepatitis C infection, hepatocellular carcinoma, human immunodeficiency virus infection, nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, and primary biliary cirrhosis are reviewed. In the absence of clinical data, nonclinical information in animal models is presented. This review aims to advance the understanding of altered expression and function of hepatic transporters in liver disease and the implications of such changes on drug disposition.
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Affiliation(s)
- Nilay Thakkar
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Jason R Slizgi
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599.
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Pomozi V, Brampton C, Szeri F, Dedinszki D, Kozák E, van de Wetering K, Hopkins H, Martin L, Váradi A, Le Saux O. Functional Rescue of ABCC6 Deficiency by 4-Phenylbutyrate Therapy Reduces Dystrophic Calcification in Abcc6 -/- Mice. J Invest Dermatol 2016; 137:595-602. [PMID: 27826008 DOI: 10.1016/j.jid.2016.10.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 12/16/2022]
Abstract
Soft-tissue calcification is associated with aging, common conditions such as diabetes or hypercholesterolemia, and with certain genetic disorders. ABCC6 is an efflux transporter primarily expressed in liver facilitating the release of adenosine triphosphate from hepatocytes. Within the liver vasculature, adenosine triphosphate is converted into pyrophosphate, a major inhibitor of ectopic calcification. ABCC6 mutations thus lead to reduced plasma pyrophosphate levels, resulting in the calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy. Most mutations in ABCC6 are missense, and many preserve transport activity but are retained intracellularly. We have previously shown that the chemical chaperone 4-phenylbutyrate (4-PBA) promotes the maturation of ABCC6 mutants to the plasma membrane. In a humanized mouse model of pseudoxanthoma elasticum, we investigated whether 4-PBA treatments could rescue the calcification inhibition potential of selected ABCC6 mutants. We used the dystrophic cardiac calcification phenotype of Abcc6-/- mice as an indicator of ABCC6 function to quantify the effect of 4-PBA on human ABCC6 mutants transiently expressed in the liver. We showed that 4-PBA administrations restored the physiological function of ABCC6 mutants, resulting in enhanced calcification inhibition. This study identifies 4-PBA treatment as a promising strategy for allele-specific therapy of ABCC6-associated calcification disorders.
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Affiliation(s)
- Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Flóra Szeri
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dóra Dedinszki
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Eszter Kozák
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Koen van de Wetering
- Division of Molecular Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Hi'ilani Hopkins
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ludovic Martin
- University of Angers, Angers, France; CHU Angers, Centre de consultation PXE, Angers, France
| | - András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
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26
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Rasmussen MR, Nielsen KL, Laursen MR, Nielsen CB, Svendsen P, Dimke H, Christensen EI, Johannsen M, Moestrup SK. Untargeted Metabolomics Analysis of ABCC6-Deficient Mice Discloses an Altered Metabolic Liver Profile. J Proteome Res 2016; 15:4591-4600. [PMID: 27758107 DOI: 10.1021/acs.jproteome.6b00669] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Loss-of-function mutations in the transmembrane ABCC6 transport protein cause pseudoxanthoma elasticum (PXE), an ectopic, metabolic mineralization disorder that affects the skin, eye, and vessels. ABCC6 is assumed to mediate efflux of one or several small molecule compounds from the liver cytosol to the circulation. Untargeted metabolomics using liquid chromatography-mass spectrometry was employed to inspect liver cytosolic extracts from mice with targeted disruption of the Abcc6 gene. Absence of the ABCC6 protein induced an altered profile of metabolites in the liver causing accumulation of compounds as more features were upregulated than downregulated in ABCC6-deficient mice. However, no differences of the identified metabolites in liver could be detected in plasma, whereas urine reflected some of the changes. Of note, N-acetylated amino acids and pantothenic acid (vitamin B5), which is involved in acetylation reactions, were accumulated in the liver. None of the identified metabolites seems to explain mineralization in extrahepatic tissues, but the present study now shows that abrogated ABCC6 function does cause alterations in the metabolic profile of the liver in accordance with PXE being a metabolic disease originating from liver disturbance. Further studies of these changes and the further identification of yet unknown metabolites may help to clarify the liver-related pathomechanism of PXE.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Søren K Moestrup
- Department of Clinical Biochemistry, Pharmacology, Odense University Hospital , Odense 5000, Denmark
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27
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Füredi A, Tóth S, Szebényi K, Pape VF, Türk D, Kucsma N, Cervenak L, Tóvári J, Szakács G. Identification and Validation of Compounds Selectively Killing Resistant Cancer: Delineating Cell Line–Specific Effects from P-Glycoprotein–Induced Toxicity. Mol Cancer Ther 2016; 16:45-56. [DOI: 10.1158/1535-7163.mct-16-0333-t] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/14/2016] [Accepted: 10/06/2016] [Indexed: 11/16/2022]
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28
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Li Q, Arányi T, Váradi A, Terry SF, Uitto J. Research Progress in Pseudoxanthoma Elasticum and Related Ectopic Mineralization Disorders. J Invest Dermatol 2016; 136:550-556. [PMID: 26902123 PMCID: PMC4765001 DOI: 10.1016/j.jid.2015.10.065] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Heritable ectopic mineralization disorders represent a phenotypically diverse group of conditions characterized by deposition of calcium phosphate complexes in soft connective tissues. The prototype of such conditions is pseudoxanthoma elasticum, and related conditions with overlapping clinical features include generalized arterial calcification of infancy and arterial calcification due to CD73 deficiency. Molecular genetic investigations have revealed mutations in the genes physiologically involved in generation of inorganic pyrophosphate and inorganic phosphate, and the findings suggest a unifying pathomechanism relating to reduced inorganic pyrophosphate/inorganic phosphate ratio. This hypothesis is based on the notion that inorganic pyrophosphate serves as a powerful inhibitor of mineralization, whereas inorganic phosphate is a promineralization factor, and an appropriate inorganic pyrophosphate/inorganic phosphate ratio is critical for prevention of ectopic mineralization under homeostatic conditions.
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Affiliation(s)
- Qiaoli Li
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Tamás Arányi
- Institute of Enzymology, RCNS, Hungarian Academy of Science, Budapest, Hungary
| | - András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Science, Budapest, Hungary
| | | | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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29
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Abstract
PURPOSE The aim of this study was to characterize peau d'orange and angioid streaks, characteristic findings in eyes of patients with pseudoxanthoma elasticum, by examining fundus photography and optical coherence tomography imaging. METHODS Color photographs were evaluated directly as were the component red and green channels. Optical coherence tomography images were evaluated for reflectivity pattern of the band corresponding to the retinal pigment epithelium-Bruch membrane complex. RESULTS Eighteen eyes of 9 patients with a mean age of 48.7 years (range, 31-61 years) were examined; 7 of them were women. Color photographs showed areas of yellowish opacification that obscured visualization of the underlying choroid. At the outer edges of this confluent area, opacification were nonconfluent changes with similar appearance and these regions were typical peau d'orange. Angioid streaks occurred within and extended up to the outer border of the confluent opacification. Underlying choroidal details could be seen through the regions of peau d'orange and through the gaps in angioid streaks. The red channel image showed increased reflectivity from the confluent deposit and improved visualization of the choroidal vasculature, except where the confluent opacification was located. Optical coherence tomography imaging showed increased reflectivity from the outer border of the retinal pigment epithelium-Bruch membrane complex. CONCLUSION The findings suggest that the confluent region is the relevant lesion, not the subconfluent zone known as peau d'orange. Imaging characteristics of the confluent area of opacity are consistent with diffuse infiltration with calcium, a chief histologic abnormality of pseudoxanthoma elasticum. The name coquille d'oeuf was suggested for the confluent area of opacity as a consequence.
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30
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Vanakker O, Callewaert B, Malfait F, Coucke P. The Genetics of Soft Connective Tissue Disorders. Annu Rev Genomics Hum Genet 2015; 16:229-55. [DOI: 10.1146/annurev-genom-090314-050039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Bert Callewaert
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Fransiska Malfait
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Paul Coucke
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
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31
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De Vilder EYG, Hosen MJ, Vanakker OM. The ABCC6 Transporter as a Paradigm for Networking from an Orphan Disease to Complex Disorders. BIOMED RESEARCH INTERNATIONAL 2015; 2015:648569. [PMID: 26356190 PMCID: PMC4555454 DOI: 10.1155/2015/648569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/15/2015] [Accepted: 06/23/2015] [Indexed: 01/16/2023]
Abstract
The knowledge on the genetic etiology of complex disorders largely results from the study of rare monogenic disorders. Often these common and rare diseases show phenotypic overlap, though monogenic diseases generally have a more extreme symptomatology. ABCC6, the gene responsible for pseudoxanthoma elasticum, an autosomal recessive ectopic mineralization disorder, can be considered a paradigm gene with relevance that reaches far beyond this enigmatic orphan disease. Indeed, common traits such as chronic kidney disease or cardiovascular disorders have been linked to the ABCC6 gene. While during the last decade the awareness of the wide ramifications of ABCC6 has increased significantly, the gene itself and the transmembrane transporter it encodes have not unveiled all of the mysteries that surround them. To gain more insights, multiple approaches are being used including next-generation sequencing, computational methods, and various "omics" technologies. Much effort is made to place the vast amount of data that is gathered in an integrated system-biological network; the involvement of ABCC6 in common disorders provides a good view on the wide implications and potential of such a network. In this review, we summarize the network approaches used to study ABCC6 and the role of this gene in several complex diseases.
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Affiliation(s)
- Eva Y. G. De Vilder
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Ophthalmology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Mohammad Jakir Hosen
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
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32
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Jin L, Jiang Q, Wu Z, Shao C, Zhou Y, Yang L, Uitto J, Wang G. Genetic heterogeneity of pseudoxanthoma elasticum: the Chinese signature profile of ABCC6 and ENPP1 mutations. J Invest Dermatol 2015; 135:1294-1302. [PMID: 25615550 PMCID: PMC4402129 DOI: 10.1038/jid.2015.10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 12/09/2014] [Accepted: 12/16/2014] [Indexed: 12/28/2022]
Abstract
Pseudoxanthoma elasticum (PXE), an autosomal recessive disorder characterized by ectopic mineralization, is caused by mutations in the ABCC6 gene. We examined clinically 29 Chinese PXE patients from unrelated families, so far the largest cohort of Asian PXE patients. In a subset of 22 patients, we sequenced ABCC6 and another candidate gene, ENPP1, and conducted pathogenicity analyses for each variant. We identified a total of 17 distinct mutations in ABCC6, 15 of them being, to our knowledge, previously unreported, including 5 frameshift and 10 missense variants. In addition, a missense mutation in combination with a recurrent nonsense mutation in ENPP1 was discovered in a pediatric PXE case. No cases with p.R1141X or del23-29 mutations, common in Caucasian patient populations, were identified. The 10 missense mutations in ABCC6 were expressed in the mouse liver via hydrodynamic tail-vein injections. One mutant protein showed cytoplasmic accumulation indicating abnormal subcellular trafficking, while the other nine mutants showed correct plasma membrane location. These nine mutations were further investigated for their pathogenicity using a recently developed zebrafish mRNA rescue assay. Minimal rescue of the morpholino-induced phenotype was achieved with eight of the nine mutant human ABCC6 mRNAs tested, implying pathogenicity. This study demonstrates that the Chinese PXE population harbors unique ABCC6 mutations. These genetic data have implications for allele-specific therapy currently being developed for PXE.
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Affiliation(s)
- Liang Jin
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Qiujie Jiang
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Zhengsheng Wu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Changxia Shao
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Yong Zhou
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Department of Dermatology, PLA General Hospital, Beijing, China
| | - Luting Yang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
| | - Gang Wang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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33
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Blazquez-Medela AM, Guihard PJ, Yao J, Jumabay M, Lusis AJ, Boström KI, Yao Y. ABCC6 deficiency is associated with activation of BMP signaling in liver and kidney. FEBS Open Bio 2015; 5:257-63. [PMID: 25893161 PMCID: PMC4398664 DOI: 10.1016/j.fob.2015.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/05/2015] [Accepted: 03/18/2015] [Indexed: 12/02/2022] Open
Abstract
ABCC6 deficiency stimulates BMP signaling in multiple organs. ABCC6 deficiency causes tissue-specific induction of BMP-related genes. Tissue-specific targeting of BMP signaling may be needed in ABCC deficiency.
Mutations in ABCC6 (ATP-binding cassette, subfamily C, member 6), an orphan transporter expressed in the liver, are the cause of pseudoxanthoma elasticum. Since ABCC6 was reported to affect matrix Gla protein (MGP), an inhibitor of bone morphogenetic proteins (BMPs), we studied BMP signaling and expression in various tissues of mice with and without functional ABCC. Enhanced BMP signaling was found in all examined tissues in the absence of ABCC6. Despite this, the expression of particular BMP proteins varied widely between tissues. Interestingly, the expression of most BMP proteins in the liver moved in the opposite direction to the same BMP proteins in kidneys in response to ABCC6 alterations. Thus, ABCC6 deficiency stimulates BMP signaling by acting on the expression of multiple BMPs.
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Affiliation(s)
- Ana M Blazquez-Medela
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States
| | - Pierre J Guihard
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States
| | - Jiayi Yao
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States
| | - Medet Jumabay
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States
| | - Aldons J Lusis
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States ; Molecular Biology Institute, UCLA, United States
| | - Kristina I Boström
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States ; Molecular Biology Institute, UCLA, United States
| | - Yucheng Yao
- Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, United States
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34
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Miglionico R, Armentano MF, Carmosino M, Salvia AM, Cuviello F, Bisaccia F, Ostuni A. Dysregulation of gene expression in ABCC6 knockdown HepG2 cells. Cell Mol Biol Lett 2014; 19:517-26. [PMID: 25169437 PMCID: PMC6275862 DOI: 10.2478/s11658-014-0208-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 08/20/2014] [Indexed: 01/31/2023] Open
Abstract
ABCC6 protein is an ATP-dependent transporter that is mainly found in the basolateral plasma membrane of hepatocytes. ABCC6 deficiency is the primary cause of several forms of ectopic mineralization syndrome. Mutations in the human ABCC6 gene cause pseudoxanthoma elasticum (PXE), an autosomal recessive disease characterized by ectopic calcification of the elastic fibers in dermal, ocular and vascular tissues. Mutations in the mouse ABCC6 gene were also associated with dystrophic cardiac calcification. Reduced levels of ABCC6 protein were found in a β-thalassemic mouse model. Moreover, some cases of generalized arterial calcification in infancy are due to ABCC6 mutations. In order to study the role of ABCC6 in the pathogenesis of ectopic mineralization, the expressions of genes involved in this process were evaluated in HepG2 cells upon stable knockdown of ABCC6 by small hairpin RNA (shRNA) technology. ABCC6 knockdown in HepG2 cells causes a significant upregulation of the genes promoting mineralization, such as TNAP, and a parallel downregulation of genes with anti-mineralization activity, such as NT5E, Fetuin A and Osteopontin. Although the absence of ABCC6 has been already associated with ectopic mineralization syndromes, this study is the first to show a direct relationship between reduced ABCC6 levels and the expression of pro-mineralization genes in hepatocytes.
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Affiliation(s)
- Rocchina Miglionico
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | | | - Monica Carmosino
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | - Antonella Maria Salvia
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | - Flavia Cuviello
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | - Faustino Bisaccia
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | - Angela Ostuni
- Department of Sciences, University of Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
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Erdei Z, Lőrincz R, Szebényi K, Péntek A, Varga N, Likó I, Várady G, Szakács G, Orbán TI, Sarkadi B, Apáti A. Expression pattern of the human ABC transporters in pluripotent embryonic stem cells and in their derivatives. CYTOMETRY PART B-CLINICAL CYTOMETRY 2014; 86:299-310. [PMID: 24729538 DOI: 10.1002/cyto.b.21168] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND ATP-binding cassette (ABC) transporters have key roles in various physiological functions as well as providing chemical defense and stress tolerance in human tissues. In this study, we have examined the expression pattern of all ABC proteins in pluripotent human embryonic stem cells (hESCs) and in their differentiated progenies. We paid special attention to the cellular expression and localization of multidrug transporter ABC proteins. METHODS Stem cell differentiation was carried out without chemical induction or cell sorting, and specialized cell types were separated mechanically. Cellular features regarding pluripotency and tissue identity, as well as ABC transporter expression were studied by flow cytomtery, immuno-microscopy, and qPCR-based low-density arrays. RESULTS Pluripotent hESCs and differentiated cell types (cardiomyocytes, neuronal cells, and mesenchymal stem cells) were distinguished by morphology, immunostaining markers, and selected mRNA expression patterns. We found that the mRNA expression levels of the 48 human ABC proteins also clearly distinguished the pluripotent and the respective differentiated cell types. When multidrug and lipid transporter ABC protein expression was examined by using well characterized specific antibodies by flow cytometry and confocal microscopy, the protein expression data corresponded well to the mRNA expression results. Moreover, the cellular localization of these important human ABC transporter proteins could be established in the pluripotent and differentiated hESC derived samples. CONCLUSIONS These studies provide valuable information regarding ABC protein expression in human stem cells and their differentiated offspring. The results may also help to obtain further information concerning the specialized cellular functions of selected ABC transporters.
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Affiliation(s)
- Zsuzsa Erdei
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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Affiliation(s)
- Friedrich C Luft
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine), Berlin, Germany,
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37
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Abstract
This review centers on updating the active research area of vascular calcification. This pathology underlies substantial cardiovascular morbidity and mortality, through adverse mechanical effects on vascular compliance, vasomotion, and, most likely, plaque stability. Biomineralization is a complex, regulated process occurring widely throughout nature. Decades ago, its presence in the vasculature was considered a mere curiosity and an unregulated, dystrophic process that does not involve biological mechanisms. Although it remains controversial whether the process has any adaptive value or past evolutionary advantage, substantial advances have been made in understanding the biological mechanisms driving the process. Different types of calcific vasculopathy, such as inflammatory versus metabolic, have parallel mechanisms in skeletal bone calcification, such as intramembranous and endochondral ossification. Recent work has identified important regulatory roles for inflammation, oxidized lipids, elastin, alkaline phosphatase, osteoprogenitor cells, matrix γ-carboxyglutamic acid protein, transglutaminase, osteoclastic regulatory factors, phosphate regulatory hormones and receptors, apoptosis, prelamin A, autophagy, and microvesicles or microparticles similar to the matrix vesicles of skeletal bone. Recent work has uncovered fascinating interactions between matrix γ-carboxyglutamic acid protein, vitamin K, warfarin, and transport proteins. And, lastly, recent breakthroughs in inherited forms of calcific vasculopathy have identified the genes responsible as well as an unexpected overlap of phenotypes. Until recently, vascular calcification was considered a purely degenerative, unregulated process. Since then, investigative groups around the world have identified a wide range of causative mechanisms and regulatory pathways, and some of the recent developments are highlighted in this review.
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Affiliation(s)
- Linda L. Demer
- Department of Medicine (Cardiology), University of California, Los Angeles Los Angeles, CA 90095-1679
- Department of Physiology and Bioengineering, University of California, Los Angeles Los Angeles, CA 90095-1679
| | - Yin Tintut
- Department of Medicine (Cardiology), University of California, Los Angeles Los Angeles, CA 90095-1679
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Kauffenstein G, Pizard A, Le Corre Y, Vessières E, Grimaud L, Toutain B, Labat C, Mauras Y, Gorgels TG, Bergen AA, Le Saux O, Lacolley P, Lefthériotis G, Henrion D, Martin L. Disseminated arterial calcification and enhanced myogenic response are associated with abcc6 deficiency in a mouse model of pseudoxanthoma elasticum. Arterioscler Thromb Vasc Biol 2014; 34:1045-56. [PMID: 24675664 DOI: 10.1161/atvbaha.113.302943] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Pseudoxanthoma elasticum is an inherited metabolic disorder resulting from ABCC6 gene mutations. It is characterized by progressive calcification and fragmentation of elastic fibers in the skin, retina, and the arterial wall. Despite calcium accumulation in the arteries of patients with pseudoxanthoma elasticum, functional consequences remain unknown. In the present study, we investigated arterial structure and function in Abcc6(-/-) mice, a model of the human disease. APPROACH AND RESULTS Arterial calcium accumulation was evaluated using alizarin red stain and atomic absorption spectrometry. Expression of genes involved in osteochondrogenic differentiation was measured by polymerase chain reaction. Elastic arterial properties were evaluated by carotid echotracking. Vascular reactivity was evaluated using wire and pressure myography and remodeling using histomorphometry. Arterial calcium accumulation was 1.5- to 2-fold higher in Abcc6(-/-) than in wild-type mice. Calcium accumulated locally leading to punctuate pattern. Old Abcc6(-/-) arteries expressed markers of both osteogenic (Runx2, osteopontin) and chondrogenic lineage (Sox9, type II collagen). Abcc6(-/-) arteries displayed slight increase in arterial stiffness and vasoconstrictor tone in vitro tended to be higher in response to phenylephrine and thromboxane A2. Pressure-induced (myogenic) tone was significantly higher in Abcc6(-/-) arteries than in wild type. Arterial blood pressure was not significantly changed in Abcc6(-/-), despite higher variability. CONCLUSIONS Scattered arterial calcium depositions are probably a result of osteochondrogenic transdifferentiation of vascular cells. Lower elasticity and increased myogenic tone without major changes in agonist-dependent contraction evidenced in aged Abcc6(-/-) mice suggest a reduced control of local blood flow, which in turn may alter vascular homeostasis in the long term.
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Affiliation(s)
- Gilles Kauffenstein
- From the CNRS UMR 6214, INSERM U1083, l'UNAM (G.K., Y.L.C., E.V., L.G., B.T., G.L., D.H., L.M.) and Laboratoire de Pharmacologie-Toxicologie, l'UNAM, Université d'Angers (Y.M.), University Hospital Angers, Angers, France; INSERM, U1116 (A.P., C.L., P.L.), Université de Lorraine, Vandoeuvre-lès-Nancy, France; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI (O.L.S.); Molecular Ophthalmogenetics, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands (T.G.G., A.A.B.); and Departments of Ophthalmology (A.A.B.) and Clinical Genetics (A.A.B.), Academic Medical Center, Amsterdam, The Netherlands
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Brampton C, Aherrahrou Z, Chen LH, Martin L, Bergen AA, Gorgels TG, Erdfdi J, Schunkert H, Szabó Z, Váradi A, Le Saux O. The level of hepatic ABCC6 expression determines the severity of calcification after cardiac injury. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:159-70. [PMID: 24479134 PMCID: PMC3873484 DOI: 10.1016/j.ajpath.2013.09.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/18/2013] [Indexed: 12/22/2022]
Abstract
Because vascular or cardiac mineralization is inversely correlated with morbidity and long-term survival, we investigated the role of ABCC6 in the calcification response to cardiac injury in mice. By using two models of infarction, nonischemic cryoinjury and the pathologically relevant coronary artery ligation, we confirmed a large propensity to acute cardiac mineralization in Abcc6−/− mice. Furthermore, when the expression of ABCC6 was reduced to approximately 38% of wild-type levels in Abcc6+/− mice, no calcium deposits in injured cardiac tissue were observed. In addition, we used a gene therapy approach to deliver a functional human ABCC6 via hydrodynamic tail vein injection to approximately 13% of mouse hepatocytes, significantly reducing the calcification response to cardiac cryoinjury. We observed that the level and distribution of known regulators of mineralization, such as osteopontin and matrix Gla protein, but not osteocalcin, were concomitant to the level of hepatic expression of human and mouse ABCC6. We notably found that undercarboxylated matrix Gla protein precisely colocalized within areas of mineralization, whereas osteopontin was more diffusely distributed in the area of injury, suggesting a prominent association for matrix Gla protein and osteopontin in ABCC6-related dystrophic cardiac calcification. This study showed that the expression of ABCC6 in liver is an important determinant of calcification in cardiac tissues in response to injuries and is associated with changes in the expression patterns of regulators of mineralization.
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Affiliation(s)
- Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Zouhair Aherrahrou
- Institute for Integrative and Experimental Genomics, German Centre for Cardiovascular Research, partner site Lübeck/Hamburg/Kiel, University of Luebeck, Luebeck, Germany
| | - Li-Hsieh Chen
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Ludovic Martin
- Integrated Neurovascular and Mitochondrial Biology, L’UNAM University, UMR CNRS/INSERM, Angers School of Medicine, Angers, France
| | - Arthur A.B. Bergen
- Department of Molecular Ophthalmogenetics, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands
- Department of Ophthalmology, Academic Medical Center, Amsterdam, the Netherlands
| | - Theo G.M.F. Gorgels
- Department of Molecular Ophthalmogenetics, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Jeannette Erdfdi
- Institute for Integrative and Experimental Genomics, German Centre for Cardiovascular Research, partner site Lübeck/Hamburg/Kiel, University of Luebeck, Luebeck, Germany
| | - Heribert Schunkert
- German Heart Center Munich, German Centre for Cardiovascular Research, partner site Munich Heart Alliance, Munich, Germany
| | - Zalán Szabó
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
| | - András Váradi
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
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Reyes JF, Rey NL, Bousset L, Melki R, Brundin P, Angot E. Alpha-synuclein transfers from neurons to oligodendrocytes. Glia 2013; 62:387-98. [PMID: 24382629 DOI: 10.1002/glia.22611] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 11/13/2013] [Accepted: 11/15/2013] [Indexed: 01/13/2023]
Abstract
The origin of α-synuclein (α-syn)-positive glial cytoplasmic inclusions found in oligodendrocytes in multiple system atrophy (MSA) is enigmatic, given the fact that oligodendrocytes do not express α-syn mRNA. Recently, neuron-to-neuron transfer of α-syn was suggested to contribute to the pathogenesis of Parkinson's disease. In this study, we explored whether a similar transfer of α-syn might occur from neurons to oligodendrocytes, which conceivably could explain how glial cytoplasmic inclusions are formed. We studied oligodendrocytes in vitro and in vivo and examined their ability to take up different α-syn assemblies. First, we treated oligodendrocytes with monomeric, oligomeric, and fibrillar forms of α-syn proteins and investigated whether α-syn uptake is dynamin-dependent. Second, we injected the same α-syn species into the mouse cortex to assess their uptake in vivo. Finally, we monitored the presence of human α-syn within rat oligodendroglial cells grafted in the striatum of hosts displaying Adeno-Associated Virus-mediated overexpression of human α-syn in the nigro-striatal pathway. Here, we show that oligodendrocytes take up recombinant α-syn monomers, oligomers and, to a lesser extent, fibrils in vitro in a concentration and time-dependent manner, and that this process is inhibited by dynasore. Further, we demonstrate in our injection model that oligodendrocytes also internalize α-syn in vivo. Finally, we provide the first direct evidence that α-syn can transfer to grafted oligodendroglial cells from host rat brain neurons overexpressing human α-syn. Our findings support the hypothesis of a neuron-to-oligodendrocyte transfer of α-syn, a mechanism that may play a crucial role in the progression and pathogenesis of MSA.
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Affiliation(s)
- Juan F Reyes
- Neuronal Survival Unit, BMC B11, Department of Experimental Medical Science, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
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Pomozi V, Brampton C, Fülöp K, Chen LH, Apana A, Li Q, Uitto J, Le Saux O, Váradi A. Analysis of pseudoxanthoma elasticum-causing missense mutants of ABCC6 in vivo; pharmacological correction of the mislocalized proteins. J Invest Dermatol 2013; 134:946-953. [PMID: 24352041 PMCID: PMC3962510 DOI: 10.1038/jid.2013.482] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/26/2013] [Accepted: 09/06/2013] [Indexed: 01/10/2023]
Abstract
Mutations in the ABCC6 gene cause soft-tissue calcification in pseudoxanthoma elasticum (PXE) and, in some patients, generalized arterial calcification of infancy (GACI). PXE is characterized by late onset and progressive mineralization of elastic fibers in dermal, ocular, and cardiovascular tissues. GACI patients present a more severe, often prenatal arterial calcification. We have tested 10 frequent disease-causing ABCC6 missense mutants for the transport activity by using Sf9 (Spodoptera frugiperda) cells, characterized the subcellular localization in MDCKII (Madin-Darby canine kidney (cell line)) cells and in mouse liver, and tested the phenotypic rescue in zebrafish. We aimed at identifying mutants with preserved transport activity but with improper plasma membrane localization for rescue by the chemical chaperone 4-phenylbutyrate (4-PBA). Seven of the mutants were transport-competent but mislocalized in mouse liver. The observed divergence in cellular localization of mutants in MDCKII cells versus mouse liver underlined the limitations of this 2D in vitro cell system. The functionality of ABCC6 mutants was tested in zebrafish, and minimal rescue of the morpholino-induced phenotype was found. However, 4-PBA, a drug approved for clinical use, restored the plasma membrane localization of four ABCC6 mutants (R1114P, S1121W, Q1347H, and R1314W), suggesting that allele-specific therapy may be useful for selected patients with PXE and GACI.
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Affiliation(s)
- Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Christopher Brampton
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Krisztina Fülöp
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Li-Hsieh Chen
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ailea Apana
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Qiaoli Li
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary.
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Ferré M, Reynier P, Chevrollier A, Prunier-Mirebeau D, Lefthériotis G, Henrion D, Bonneau D, Procaccio V, Martin L. Is ABCC6 a genuine mitochondrial protein? BMC Res Notes 2013; 6:427. [PMID: 24152371 PMCID: PMC4015885 DOI: 10.1186/1756-0500-6-427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 10/11/2013] [Indexed: 12/02/2022] Open
Abstract
Background A recent article in Circulation Research suggests that the protein ABCC6, which when defective is responsible for pseudoxanthoma elasticum, an inherited condition with skin, eye and cardiovascular manifestations, is associated with dysfunction in mitochondria – Martin et al.: ABCC6 Localizes to the Mitochondria-Associated Membrane.Circ Res 2012, 111:516–520. We present complementary information based on a bioinformatics analysis, which was not performed in the article cited, to examine the suggestion that ABCC6 is localized to mitochondria. Results All the computational strategies and integrative approaches that constitute references in the field indicate that ABCC6 is localized outside of mitochondria. Conclusion Our computational and integrative results, including both experimental and predictive data, show that there is no support in favor of the localization of ABCC6 in mitochondria.
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Affiliation(s)
- Marc Ferré
- CNRS 6214/INSERM 1083, Angers University, Angers, France.
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43
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Vanakker OM, Hosen MJ, Paepe AD. The ABCC6 transporter: what lessons can be learnt from other ATP-binding cassette transporters? Front Genet 2013; 4:203. [PMID: 24137173 PMCID: PMC3797522 DOI: 10.3389/fgene.2013.00203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 09/23/2013] [Indexed: 01/31/2023] Open
Abstract
ABC transporters represent a large family of ATP-driven transmembrane transporters involved in uni- or bidirectional transfer of a large variety of substrates. Divided in seven families, they represent 48 transporter proteins, several of which have been associated with human disease. Among the latter is ABCC6, a unidirectional exporter protein primarily expressed in liver and kidney. ABCC6 deficiency has been shown to cause the ectopic mineralization disorder pseudoxanthoma elasticum (PXE), characterized by calcification and fragmentation of elastic fibers, resulting in oculocutaneous and cardiovascular symptoms. Unique in the group of connective tissue disorders, the pathophysiological relation between the ABCC6 transporter and ectopic mineralization in PXE remains enigmatic, not in the least because of lack of knowledge on the substrate(s) of ABCC6 and its unusual expression pattern. Because many features, including structure and transport mechanism, are shared by many ABC transporters, it is worthwhile to evaluate if and to what extent the knowledge on the physiology and pathophysiology of these other transporters may provide useful clues toward understanding the (patho)physiological role of ABCC6 and how its deficiency may be dealt with.
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Li Q, Jiang Q, Uitto J. Ectopic mineralization disorders of the extracellular matrix of connective tissue: molecular genetics and pathomechanisms of aberrant calcification. Matrix Biol 2013; 33:23-8. [PMID: 23891698 DOI: 10.1016/j.matbio.2013.06.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 01/07/2023]
Abstract
Ectopic mineralization of connective tissues is a complex process leading to deposition of calcium phosphate complexes in the extracellular matrix, particularly affecting the skin and the arterial blood vessels and common in age-associated disorders. A number of initiating and contributing metabolic and environmental factors are linked to aberrant mineralization in these diseases, making the identification of precise pathomechanistic pathways exceedingly difficult. However, there has been significant recent progress in understanding the ectopic mineralization processes through study of heritable single-gene disorders, which have allowed identification of discrete pathways and contributing factors leading to aberrant connective tissue mineralization. These studies have provided support for the concept of an intricate mineralization/anti-mineralization network present in peripheral connective tissues, providing a perspective to development of pharmacologic approaches to limit the phenotypic consequences of ectopic mineralization. This overview summarizes the current knowledge of ectopic heritable mineralization disorders, with accompanying animal models, focusing on pseudoxanthoma elasticum and generalized arterial calcification of infancy, two autosomal recessive diseases manifesting with extensive connective tissue mineralization in the skin and the cardiovascular system.
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Affiliation(s)
- Qiaoli Li
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, 233 S. 10th Street, Philadelphia, PA, United States
| | - Qiujie Jiang
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, 233 S. 10th Street, Philadelphia, PA, United States
| | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, 233 S. 10th Street, Philadelphia, PA, United States.
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Martin LJ, Lau E, Singh H, Vergnes L, Tarling EJ, Mehrabian M, Mungrue I, Xiao S, Shih D, Castellani L, Ping P, Reue K, Stefani E, Drake TA, Bostrom K, Lusis AJ. Response to Pomozi et al's research commentary. Circ Res 2013; 112:e152-3. [PMID: 23625949 DOI: 10.1161/circresaha.113.301666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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