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Brampton C, Pomozi V, Le Corre Y, Zoll J, Kauffenstein G, Ma C, Hoffmann PR, Martin L, Le Saux O. Bone Marrow-Derived ABCC6 Is an Essential Regulator of Ectopic Calcification In Pseudoxanthoma Elasticum. J Invest Dermatol 2024:S0022-202X(24)00110-6. [PMID: 38367909 DOI: 10.1016/j.jid.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/31/2023] [Accepted: 01/26/2024] [Indexed: 02/19/2024]
Abstract
Physiological calcification of soft tissues is a common occurrence in aging and various acquired and inherited disorders. ABCC6 sequence variations cause the calcification phenotype of pseudoxanthoma elasticum (PXE) as well as some cases of generalized arterial calcification of infancy, which is otherwise caused by defective ENPP1. ABCC6 is primarily expressed in the liver, which has given the impression that the liver is central to the pathophysiology of PXE/generalized arterial calcification of infancy. The emergence of inflammation as a contributor to the calcification in PXE suggested that peripheral tissues play a larger role than expected. In this study, we investigated whether bone marrow-derived ABCC6 contributes to the calcification in PXE. In Abcc6‒/‒ mice, we observed prevalent mineralization in several lymph nodes and surrounding connective tissues and an extensive network of lymphatic vessels within vibrissae, a calcified tissue in Abcc6‒/‒ mice. Furthermore, we found evidence of lymphangiogenesis in patients with PXE and mouse skin, suggesting an inflammatory process. Finally, restoring wild-type bone marrow in Abcc6‒/‒ mice produced a significant reduction of calcification, suggesting that the liver alone is not sufficient to fully inhibit mineralization. With evidence that ABCC6 is expressed in lymphocytes, we suggest that the adaptative immune system and inflammation largely contribute to the calcification in PXE/generalized arterial calcification of infancy.
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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, USA; Bio-Rad Laboratories, Hercules, California, USA
| | - 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 Centre of Excellence, Budapest, Hungary
| | - Yannick Le Corre
- PXE National Reference Center (MAGEC Nord), University Hospital of Angers, Angers, France
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Gilles Kauffenstein
- UMR INSERM 1260, Nano Regenerative Medicine, University of Strasbourg, Strasbourg, France
| | - Chi Ma
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Peter R Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ludovic Martin
- PXE National Reference Center (MAGEC Nord), University Hospital of Angers, Angers, France; CNRS 6015, UMR INSERM U1083, MITOVASC Laboratory, University of Angers, Angers, France
| | - 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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Kauffenstein G, Martin L, Le Saux O. The Purinergic Nature of Pseudoxanthoma Elasticum. Biology (Basel) 2024; 13:74. [PMID: 38392293 PMCID: PMC10886499 DOI: 10.3390/biology13020074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/13/2024] [Accepted: 01/19/2024] [Indexed: 02/24/2024]
Abstract
Pseudoxanthoma Elasticum (PXE) is an inherited disease characterized by elastic fiber calcification in the eyes, the skin and the cardiovascular system. PXE results from mutations in ABCC6 that encodes an ABC transporter primarily expressed in the liver and kidneys. It took nearly 15 years after identifying the gene to better understand the etiology of PXE. ABCC6 function facilitates the efflux of ATP, which is sequentially hydrolyzed by the ectonucleotidases ENPP1 and CD73 into pyrophosphate (PPi) and adenosine, both inhibitors of calcification. PXE, together with General Arterial Calcification of Infancy (GACI caused by ENPP1 mutations) as well as Calcification of Joints and Arteries (CALJA caused by NT5E/CD73 mutations), forms a disease continuum with overlapping phenotypes and shares steps of the same molecular pathway. The explanation of these phenotypes place ABCC6 as an upstream regulator of a purinergic pathway (ABCC6 → ENPP1 → CD73 → TNAP) that notably inhibits mineralization by maintaining a physiological Pi/PPi ratio in connective tissues. Based on a review of the literature and our recent experimental data, we suggest that PXE (and GACI/CALJA) be considered as an authentic "purinergic disease". In this article, we recapitulate the pathobiology of PXE and review molecular and physiological data showing that, beyond PPi deficiency and ectopic calcification, PXE is associated with wide and complex alterations of purinergic systems. Finally, we speculate on the future prospects regarding purinergic signaling and other aspects of this disease.
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Affiliation(s)
- Gilles Kauffenstein
- UMR INSERM 1260, Regenerative Nanomedicine, University of Strasbourg, 67084 Strasbourg, France
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Nord Reference Center for Rare Skin Diseases, Angers University Hospital, 49000 Angers, France
- MITOVASC-UMR CNRS 6015 INSERM 1083, University of Angers, 49000 Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Leftheriotis G, Navasiolava N, Clotaire L, Duranton C, Le Saux O, Bendahhou S, Laurain A, Rubera I, Martin L. Relationships between Plasma Pyrophosphate, Vascular Calcification and Clinical Severity in Patients Affected by Pseudoxanthoma Elasticum. J Clin Med 2022; 11:jcm11092588. [PMID: 35566717 PMCID: PMC9100273 DOI: 10.3390/jcm11092588] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 12/10/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE; OMIM 264800) is an autosomal recessive metabolic disorder characterized by progressive calcification in the skin, the Bruch’s membrane, and the vasculature. Calcification in PXE results from a low level of circulating pyrophosphate (PPi) caused by ABCC6 deficiency. In this study, we used a cohort of 107 PXE patients to determine the pathophysiological relationship between plasma PPi, coronary calcification (CAC), lower limbs arterial calcification (LLAC), and disease severity. Overall, our data showed a deficit in plasma PPi in PXE patients compared to controls. Remarkably, affected females showed higher PPi levels than males, but a lower LLAC. There was a strong correlation between age and PPi in PXE patients (r = 0.423, p < 0.0001) but not in controls (r = 0.059, p = 0.828). A weak correlation was found between PPi and CAC (r = 0.266, p < 0.02); however, there was no statistically significant connection with LLAC (r = 0.068, p = 0.518) or a severity score (r = 0.077, p = 0.429). Surprisingly, we found no significant correlation between plasma alkaline phosphatase activity and PPi (r = 0.113, p = 0.252) or between a 10-year cardiovascular risk score and all other variables. Multivariate analysis confirmed that LLAC and CAC were strongly dependent on age, but not on PPi. Our data showed that arterial calcification is only weakly linked to circulating PPi levels and that time (i.e., age) appears to be the major determinant of disease severity and calcification in PXE. These data are important to better understand the natural history of this disease but also for the follow-up and management of patients, and the design of future clinical trials. Our results also show that PPi is not a good biomarker for the evaluation of disease severity and progression.
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Affiliation(s)
- Georges Leftheriotis
- University Hospital Nice, Vascular Physiology and Medicine Unit, 06000 Nice, France
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
- Correspondence: or
| | - Nastassia Navasiolava
- PXE Reference Center, MAGEC Nord, University Hospital of Angers, 49000 Angers, France; (N.N.); (L.M.)
| | - Laetitia Clotaire
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Christophe Duranton
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA;
| | - Saïd Bendahhou
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Audrey Laurain
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Isabelle Rubera
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Ludovic Martin
- PXE Reference Center, MAGEC Nord, University Hospital of Angers, 49000 Angers, France; (N.N.); (L.M.)
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Roberts FL, Rashdan NA, Phadwal K, Markby GR, Dillon S, Zoll J, Berger J, Milne E, Orriss IR, Karsenty G, Le Saux O, Morton NM, Farquharson C, MacRae VE. Osteoblast-specific deficiency of ectonucleotide pyrophosphatase or phosphodiesterase-1 engenders insulin resistance in high-fat diet fed mice. J Cell Physiol 2021; 236:4614-4624. [PMID: 33305372 PMCID: PMC9665351 DOI: 10.1002/jcp.30194] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 11/14/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022]
Abstract
Supraphysiological levels of the osteoblast-enriched mineralization regulator ectonucleotide pyrophosphatase or phosphodiesterase-1 (NPP1) is associated with type 2 diabetes mellitus. We determined the impact of osteoblast-specific Enpp1 ablation on skeletal structure and metabolic phenotype in mice. Female, but not male, 6-week-old mice lacking osteoblast NPP1 expression (osteoblast-specific knockout [KO]) exhibited increased femoral bone volume or total volume (17.50% vs. 11.67%; p < .01), and reduced trabecular spacing (0.187 vs. 0.157 mm; p < .01) compared with floxed (control) mice. Furthermore, an enhanced ability of isolated osteoblasts from the osteoblast-specific KO to calcify their matrix in vitro compared to fl/fl osteoblasts was observed (p < .05). Male osteoblast-specific KO and fl/fl mice showed comparable glucose and insulin tolerance despite increased levels of insulin-sensitizing under-carboxylated osteocalcin (195% increase; p < .05). However, following high-fat-diet challenge, osteoblast-specific KO mice showed impaired glucose and insulin tolerance compared with fl/fl mice. These data highlight a crucial local role for osteoblast NPP1 in skeletal development and a secondary metabolic impact that predominantly maintains insulin sensitivity.
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Affiliation(s)
- Fiona L. Roberts
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Nabil A. Rashdan
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Kanchan Phadwal
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Greg R. Markby
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Scott Dillon
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Julian Berger
- Department of Genetics and Development, Columbia University Medical Center, New York, New York, USA
| | - Elspeth Milne
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Isabel R. Orriss
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University Medical Center, New York, New York, USA
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Nicholas M. Morton
- Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, UK
| | - Colin Farquharson
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
| | - Vicky E. MacRae
- Functional Genetics and Development, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, UK
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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: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Brampton C, Pomozi V, Chen LH, Apana A, McCurdy S, Zoll J, Boisvert WA, Lambert G, Henrion D, Blanchard S, Kuo S, Leftheriotis G, Martin L, Le Saux O. ABCC6 deficiency promotes dyslipidemia and atherosclerosis. Sci Rep 2021; 11:3881. [PMID: 33594095 PMCID: PMC7887252 DOI: 10.1038/s41598-021-82966-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/25/2021] [Indexed: 02/08/2023] Open
Abstract
ABCC6 deficiency promotes ectopic calcification; however, circumstantial evidence suggested that ABCC6 may also influence atherosclerosis. The present study addressed the role of ABCC6 in atherosclerosis using Ldlr-/- mice and pseudoxanthoma elasticum (PXE) patients. Mice lacking the Abcc6 and Ldlr genes were fed an atherogenic diet for 16 weeks before intimal calcification, aortic plaque formation and lipoprotein profile were evaluated. Cholesterol efflux and the expression of several inflammation, atherosclerosis and cholesterol homeostasis-related genes were also determined in murine liver and bone marrow-derived macrophages. Furthermore, we examined plasma lipoproteins, vascular calcification, carotid intima-media thickness and atherosclerosis in a cohort of PXE patients with ABCC6 mutations and compared results to dysmetabolic subjects with increased cardiovascular risk. We found that ABCC6 deficiency causes changes in lipoproteins, with decreased HDL cholesterol in both mice and humans, and induces atherosclerosis. However, we found that the absence of ABCC6 does not influence overall vascular mineralization induced with atherosclerosis. Decreased cholesterol efflux from macrophage cells and other molecular changes such as increased pro-inflammation seen in both humans and mice are likely contributors for the phenotype. However, it is likely that other cellular and/or molecular mechanisms are involved. Our study showed a novel physiological role for ABCC6, influencing plasma lipoproteins and atherosclerosis in a haploinsufficient manner, with significant penetrance.
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Affiliation(s)
- Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA
- Bio-Rad Laboratories, Inc., Hercules, CA, USA
| | - Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA
| | - Li-Hsieh Chen
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA
| | - Ailea Apana
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA
| | - Sara McCurdy
- Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
- Department of Medicine, University of California San Diego, San Diego, USA
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA
| | - William A Boisvert
- Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Gilles Lambert
- University of La Réunion Medical School (France) INSERM UMR1188 DéTROI, Ste Clotilde, La Réunion, France
| | - Daniel Henrion
- MITOVASC Institute - UMR CNRS 6015 INSERM U1083, University of Angers, Angers, France
| | - Simon Blanchard
- Département d'Immunologie et d'Allergologie, University Hospital of Angers, 49000, Angers, France
- Inserm U1232, CRCINA, University of Angers, 44000, Nantes, France
| | - Sheree Kuo
- Department of Pediatrics Kapi'olani Medical Center for Women and Children, University of Hawaii, Honolulu, HI, USA
| | - Georges Leftheriotis
- Faculty of Medicine, University of Nice-Sophia Antipolis, 06107, Nice, France
- Laboratory of Physiology and Molecular Medicine (LP2M) UMR CNRS 7073, 06107, Nice, France
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Reference Center for Rare Skin Diseases, Angers University Hospital, Angers, France
- BNMI, CNRS 6214/INSERM 1083, University Bretagne-Loire, Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo St. BSB222E, Honolulu, HI, USA.
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Panee J, Pomozi V, Franke AA, Le Saux O, Gerschenson M. Chronic marijuana use moderates the correlations of serum cholesterol with systemic mitochondrial function and fluid cognition. Mitochondrion 2020; 52:135-143. [PMID: 32169611 DOI: 10.1016/j.mito.2020.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/17/2020] [Accepted: 03/09/2020] [Indexed: 11/24/2022]
Abstract
Activating type 1 cannabinoid (CB1) receptor decreases the particle size of high-density lipoprotein (HDL) and inhibits reverse cholesterol transport (RCT). This study examined whether marijuana (MJ) use is associated with changes of RCT, and how the latter is associated with mitochondrial function and fluid cognition. We recruited 19 chronic MJ users and 20 nonusers with matched age, BMI, sex, ethnicity, and education. We measured their fluid cognition, mitochondrial function (basal and max respiration, ATP production) in peripheral blood mononuclear cells, cholesterol content in serum lipoprotein fractions, enterolactone/creatinine ratio in urine as a marker for dietary polyphenol intake, and lipase activity in serum. We found that higher percentage of large HDL cholesterol (HDL-C) correlated positively, while that of small HDL-C correlated inversely, with mitochondrial function among MJ users, but correlations of the opposite directions were found among nonusers. The concentrations of large and intermediate HDL-C correlated positively with mitochondrial function and fluid cognition among MJ users, but not among nonusers. Both percentage and concentration of large HDL-C correlated positively, while those of small HDL-C correlated inversely, with amounts of daily and lifetime MJ use. In all participants, higher urinary enterolactone/creatinine ratio and lower serum lipase activity were associated with higher large HDL-C/small HDL-C ratio, implying greater RCT. This study suggests that high MJ use may compromise RCT, which is strongly associated with mitochondrial function and fluid cognition among MJ users.
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Affiliation(s)
- Jun Panee
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA.
| | - Viola Pomozi
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA
| | - Adrian A Franke
- Cancer Biology Program, University of Hawaii Cancer Center, 701 Ilalo Street, Honolulu, HI 96813, USA
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA
| | - Mariana Gerschenson
- Department of Cell and Molecular Biology, John A Burns School of Medicine, University of Hawaii, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA
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De Vilder EYG, Cardoen S, Hosen MJ, Le Saux O, De Zaeytijd J, Leroy BP, De Reuck J, Coucke PJ, De Paepe A, Hemelsoet D, Vanakker OM. Pathogenic variants in the ABCC6 gene are associated with an increased risk for ischemic stroke. Brain Pathol 2019; 28:822-831. [PMID: 29722917 DOI: 10.1111/bpa.12620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/29/2018] [Indexed: 12/11/2022] Open
Abstract
Ischemic stroke causes a high mortality and morbidity worldwide. It results from a complex interplay of incompletely known environmental and genetic risk factors. We investigated the ABCC6 gene as a candidate risk factor for ischemic stroke because of the increased ischemic stroke incidence in the autosomal recessive disorder pseudoxanthoma elasticum, caused by biallelic pathogenic ABCC6 variants, the higher cardiovascular risk in heterozygous carriers and the established role of ABCC6 dysfunction in myocardial ischemia. We established segregation of a known pathogenic ABCC6 variant (p.[Arg1314Gln]) in 11/19 family members of an ischemic stroke patient in a large multigenerational family suffering from ischemic stroke and/or cardiovascular disease at a relatively young age. In an independent case-control study in 424 ischemic stroke patients and 250 healthy controls, pathogenic ABCC6 variants were 4.9 times more frequent (P = 0.036; 95% CI 1.11-21.33) in the ischemic stroke patient cohort. To study cellular consequences of ABCC6 deficiency in the brain, immunostaining of brain sections in Abcc6-deficient mice and wild-type controls were performed. An upregulation of Bmp4 and Eng and a downregulation of Alk2 was identified in Abcc6-/- mice, suggesting an increase in apoptosis and angiogenesis. As both of these processes are induced in ischemia, we propose that a pro-ischemic state may explain the higher risk to suffer from ischemic stroke in patients carrying a pathogenic ABCC6 variant, as this may lower the threshold to develop acute ischemic events in these patients. In conclusion, this study identified heterozygous ABCC6 variants as a risk factor for ischemic stroke. Further, dysregulation of Bmp (Bmp4, Alk2) and Tgfβ (Eng) signaling in the brain of Abcc6-/- mice could lead to a pro-ischemic state, lowering the threshold to develop acute ischemic events. These data demonstrate the importance of a molecular analysis of the ABCC6 gene in patients diagnosed with cryptogenic ischemic stroke.
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Affiliation(s)
- Eva Y G De Vilder
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Ophthalmology, Ghent University Hospital, Ghent, Belgium.,Research Foundation - Flanders, Brussels, Belgium
| | - Stefanie Cardoen
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Mohammad J Hosen
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, The John A. Burns School of Medicine, University of Hawai'i, Honolulu, HI
| | - Julie De Zaeytijd
- Department of Ophthalmology, Ghent University Hospital, Ghent, Belgium
| | - Bart P Leroy
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Ophthalmology, Ghent University Hospital, Ghent, Belgium.,Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Jacques De Reuck
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Paul J Coucke
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Anne De Paepe
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Letavernier E, Kauffenstein G, Huguet L, Navasiolava N, Bouderlique E, Tang E, Delaitre L, Bazin D, de Frutos M, Gay C, Perez J, Verpont MC, Haymann JP, Pomozi V, Zoll J, Le Saux O, Daudon M, Leftheriotis G, Martin L. ABCC6 Deficiency Promotes Development of Randall Plaque. J Am Soc Nephrol 2018; 29:2337-2347. [PMID: 29991491 DOI: 10.1681/asn.2017101148] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/28/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is a genetic disease caused by mutations in the ABCC6 gene that result in low pyrophosphate levels and subsequent progressive soft tissue calcifications. PXE mainly affects the skin, retina, and arteries. However, many patients with PXE experience kidney stones. We determined the prevalence of this pathology in patients with PXE and examined the possible underlying mechanisms in murine models. METHODS We conducted a retrospective study in a large cohort of patients with PXE and analyzed urine samples and kidneys from Abcc6-/- mice at various ages. We used Yasue staining, scanning electron microscopy, electron microscopy coupled to electron energy loss spectroscopy, and Fourier transform infrared microspectroscopy to characterize kidney calcifications. RESULTS Among 113 patients with PXE, 45 (40%) had a past medical history of kidney stones. Five of six computed tomography scans performed showed evidence of massive papillary calcifications (Randall plaques). Abcc6-/- mice spontaneously developed kidney interstitial apatite calcifications with aging. These calcifications appeared specifically at the tip of the papilla and formed Randall plaques similar to those observed in human kidneys. Compared with controls, Abcc6-/- mice had low urinary excretion of pyrophosphate. CONCLUSIONS The frequency of kidney stones and probably, Randall plaque is extremely high in patients with PXE, and Abcc6-/- mice provide a new and useful model in which to study Randall plaque formation. Our findings also suggest that pyrophosphate administration should be evaluated for the prevention of Randall plaque and kidney stones.
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Affiliation(s)
- Emmanuel Letavernier
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France; .,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Tenon, Paris, France
| | - Gilles Kauffenstein
- Institut des maladies mitochondriales, du coeur et des vaisseaux-MITOVASC, Centre National de la Recherche Scientifique 6015, Institut National de la Santé et de la Recherche Médicale U1083, Angers University, Angers, France
| | - Léa Huguet
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Nastassia Navasiolava
- Department of Dermatology, PseudoXanthoma Elasticum Consultation center, Reference Center for rare skin diseases, Angers University Hospital, France
| | - Elise Bouderlique
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Ellie Tang
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Léa Delaitre
- Department of Dermatology, PseudoXanthoma Elasticum Consultation center, Reference Center for rare skin diseases, Angers University Hospital, France
| | - Dominique Bazin
- Unité Mixte de Recherche 8502, Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, Université Paris Sud XI, Orsay, France
| | - Marta de Frutos
- Unité Mixte de Recherche 8502, Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, Université Paris Sud XI, Orsay, France
| | - Clément Gay
- Unité Mixte de Recherche 8502, Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, Université Paris Sud XI, Orsay, France
| | - Joëlle Perez
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Marie-Christine Verpont
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Jean-Philippe Haymann
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Tenon, Paris, France
| | - Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii; and
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii; and
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii; and
| | - Michel Daudon
- Unité Mixte de Recherche S 1155, Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Paris, France.,Unité Mixte de Recherche S 1155, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Tenon, Paris, France
| | - Georges Leftheriotis
- Department of Physiology and Molecular Medicine, Unité Mixte de Recherche 7370, Centre National de la Recherche Scientifique, University of Nice, Nice, France
| | - Ludovic Martin
- Institut des maladies mitochondriales, du coeur et des vaisseaux-MITOVASC, Centre National de la Recherche Scientifique 6015, Institut National de la Santé et de la Recherche Médicale U1083, Angers University, Angers, France.,Department of Dermatology, PseudoXanthoma Elasticum Consultation center, Reference Center for rare skin diseases, Angers University Hospital, France
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11
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Dedinszki D, Szeri F, Kozák E, Pomozi V, Tőkési N, Mezei TR, Merczel K, Letavernier E, Tang E, Le Saux O, Arányi T, van de Wetering K, Váradi A. Oral administration of pyrophosphate inhibits connective tissue calcification. EMBO Mol Med 2018; 9:1463-1470. [PMID: 28701330 PMCID: PMC5666306 DOI: 10.15252/emmm.201707532] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Various disorders including pseudoxanthoma elasticum (PXE) and generalized arterial calcification of infancy (GACI), which are caused by inactivating mutations in ABCC6 and ENPP1, respectively, present with extensive tissue calcification due to reduced plasma pyrophosphate (PPi). However, it has always been assumed that the bioavailability of orally administered PPi is negligible. Here, we demonstrate increased PPi concentration in the circulation of humans after oral PPi administration. Furthermore, in mouse models of PXE and GACI, oral PPi provided via drinking water attenuated their ectopic calcification phenotype. Noticeably, provision of drinking water with 0.3 mM PPi to mice heterozygous for inactivating mutations in Enpp1 during pregnancy robustly inhibited ectopic calcification in their Enpp1−/− offspring. Our work shows that orally administered PPi is readily absorbed in humans and mice and inhibits connective tissue calcification in mouse models of PXE and GACI. PPi, which is recognized as safe by the FDA, therefore not only has great potential as an effective and extremely low‐cost treatment for these currently intractable genetic disorders, but also in other conditions involving connective tissue calcification.
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Affiliation(s)
- Dóra Dedinszki
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Flóra Szeri
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Eszter Kozák
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary.,Department of Immunology, ELTE, Budapest, Hungary
| | - Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary.,Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Natália Tőkési
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás Róbert Mezei
- Department of Mathematics and its Applications Central European University, Budapest, Hungary.,Alfréd Rényi Institute of Mathematics, Hungarian Academy of Sciences, Budapest, Hungary
| | - Kinga Merczel
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Emmanuel Letavernier
- Sorbonne Universités, UPMC Univ Paris 06, UMR S 1155, Paris, France.,INSERM, UMR S 1155, Paris, France.,Physiology Unit, AP-HP, Hôpital Tenon, Paris, France
| | - Ellie Tang
- Sorbonne Universités, UPMC Univ Paris 06, UMR S 1155, Paris, France.,INSERM, UMR S 1155, Paris, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Tamás Arányi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary.,MITOVASC, CNRS UMR 6015, Inserm U1083, University of Angers, Angers, France
| | - Koen van de Wetering
- Division of Molecular Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Pomozi V, Brampton C, van de Wetering K, Zoll J, Calio B, Pham K, Owens JB, Marh J, Moisyadi S, Váradi A, Martin L, Bauer C, Erdmann J, Aherrahrou Z, Le Saux O. Pyrophosphate Supplementation Prevents Chronic and Acute Calcification in ABCC6-Deficient Mice. Am J Pathol 2017; 187:1258-1272. [PMID: 28416300 DOI: 10.1016/j.ajpath.2017.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/16/2017] [Indexed: 12/28/2022]
Abstract
Soft tissue calcification occurs in several common acquired pathologies, such as diabetes and hypercholesterolemia, or can result from genetic disorders. ABCC6, a transmembrane transporter primarily expressed in liver and kidneys, initiates a molecular pathway inhibiting ectopic calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into pyrophosphate (PPi), a major calcification inhibitor. Heritable mutations in ABCC6 underlie the incurable calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy. Herein, we determined that the administration of PPi and the bisphosphonate etidronate to Abcc6-/- mice fully inhibited the acute dystrophic cardiac calcification phenotype, whereas alendronate had no significant effect. We also found that daily injection of PPi to Abcc6-/- mice over several months prevented the development of pseudoxanthoma elasticum-like spontaneous calcification, but failed to reverse already established lesions. Furthermore, we found that the expression of low amounts of the human ABCC6 in liver of transgenic Abcc6-/- mice, resulting in only a 27% increase in plasma PPi levels, led to a major reduction in acute and chronic calcification phenotypes. This proof-of-concept study shows that the development of both acute and chronic calcification associated with ABCC6 deficiency can be prevented by compensating PPi deficits, even partially. Our work indicates that PPi substitution represents a promising strategy to treat ABCC6-dependent 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
| | - Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Bianca Calio
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Kevin Pham
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Jesse B Owens
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Joel Marh
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Stefan Moisyadi
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - András Váradi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ludovic Martin
- Université Bretagne-Loire, Integrated Neurovascular and Mitochondrial Biology, National Center for Scientific Research 6214/INSERM 1083, Angers, France; University Hospital Angers, Center for PXE Consultation, Angers, France
| | - Carolin Bauer
- Institut für Integrative und Experimentelle Genomik Universität zu Lübeck, German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany; University Heart Centre Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - Jeanette Erdmann
- Institut für Integrative und Experimentelle Genomik Universität zu Lübeck, German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany; University Heart Centre Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - Zouhair Aherrahrou
- Institut für Integrative und Experimentelle Genomik Universität zu Lübeck, German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany; University Heart Centre Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii.
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15
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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. 0356 : Disseminated arterial calcification and enhanced myogenic response are associated with Abcc6 deficiency in a mouse model of pseudoxanthoma elasticum. Archives of Cardiovascular Diseases Supplements 2015. [DOI: 10.1016/s1878-6480(15)30155-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Leftheriotis G, Kauffenstein G, Hamel JF, Abraham P, Le Saux O, Willoteaux S, Henrion D, Martin L. The contribution of arterial calcification to peripheral arterial disease in pseudoxanthoma elasticum. PLoS One 2014; 9:e96003. [PMID: 24800819 PMCID: PMC4011742 DOI: 10.1371/journal.pone.0096003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/01/2014] [Indexed: 11/30/2022] Open
Abstract
Background and aims The contribution of arterial calcification (AC) in peripheral arterial disease (PAD) and arterial wall compressibility is a matter of debate. Pseudoxanthoma elasticum (PXE), an inherited metabolic disease due to ABCC6 gene mutations, combines elastic fiber fragmentation and calcification in various soft tissues including the arterial wall. Since AC is associated with PAD, a frequent complication of PXE, we sought to determine the role of AC in PAD and arterial wall compressibility in this group of patients. Methods and Results Arterial compressibility and patency were determined by ankle-brachial pressure index (ABI) in a cohort of 71 PXE patients (mean age 48±SD 14 yrs, 45 women) and compared to 30 controls without PAD. Lower limb arterial calcification (LLAC) was determined by non-contrast enhanced helicoidal CT-scan. A calcification score (Ca-score) was computed for the femoral, popliteal and sub-popliteal artery segments of both legs. Forty patients with PXE had an ABI<0.90 and none had an ABI>1.40. LLAC increased with age, significantly more in PXE subjects than controls. A negative association was found between LLAC and ABI (r = −0.363, p = 0.002). The LLAC was independently associated with PXE and age, and ABI was not linked to cardiovascular risk factors. Conclusions The presence of AC was associated with PAD and PXE without affecting arterial compressibility. PAD in PXE patients is probably due to proximal obstructive lesions developing independently from cardiovascular risk factors.
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Affiliation(s)
- Georges Leftheriotis
- PXE Health and Research Center, University Hospital of Angers, Angers, France
- UMR CNRS 6214 - Inserm 1083, School of Medicine, l'UNAM University, Angers, France
- * E-mail:
| | - Gilles Kauffenstein
- UMR CNRS 6214 - Inserm 1083, School of Medicine, l'UNAM University, Angers, France
| | | | - Pierre Abraham
- PXE Health and Research Center, University Hospital of Angers, Angers, France
- UMR CNRS 6214 - Inserm 1083, School of Medicine, l'UNAM University, Angers, France
| | - Olivier Le Saux
- Department Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Serge Willoteaux
- PXE Health and Research Center, University Hospital of Angers, Angers, France
- UPRES 3860, School of Medicine, l'UNAM University, Angers, France
| | - Daniel Henrion
- UMR CNRS 6214 - Inserm 1083, School of Medicine, l'UNAM University, Angers, France
| | - Ludovic Martin
- PXE Health and Research Center, University Hospital of Angers, Angers, France
- UMR CNRS 6214 - Inserm 1083, School of Medicine, l'UNAM University, Angers, France
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Hosen MJ, Coucke PJ, Le Saux O, De Paepe A, Vanakker OM. Perturbation of specific pro-mineralizing signalling pathways in human and murine pseudoxanthoma elasticum. Orphanet J Rare Dis 2014; 9:66. [PMID: 24775865 PMCID: PMC4022264 DOI: 10.1186/1750-1172-9-66] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 04/14/2014] [Indexed: 01/26/2023] Open
Abstract
Background Pseudoxanthoma elasticum (PXE) is characterized by skin (papular lesions), ocular (subretinal neovascularisation) and cardiovascular manifestations (peripheral artery disease), due to mineralization and fragmentation of elastic fibres in the extracellular matrix (ECM). Caused by mutations in the ABCC6 gene, the mechanisms underlying this disease remain unknown. The knowledge on the molecular background of soft tissue mineralization largely comes from insights in vascular calcification, with involvement of the osteoinductive Transforming Growth Factor beta (TGFβ) family (TGFβ1-3 and Bone Morphogenetic Proteins [BMP]), together with ectonucleotides (ENPP1), Wnt signalling and a variety of local and systemic calcification inhibitors. In this study, we have investigated the relevance of the signalling pathways described in vascular soft tissue mineralization in the PXE knock-out mouse model and in PXE patients. Methods The role of the pro-osteogenic pathways BMP2-SMADs-RUNX2, TGFβ-SMAD2/3 and Wnt-MSX2, apoptosis and ER stress was evaluated using immunohistochemistry, mRNA expression profiling and immune-co-staining in dermal tissues and fibroblast cultures of PXE patients and the eyes and whiskers of the PXE knock-out mouse. Apoptosis was further evaluated by TUNEL staining and siRNA mediated gene knockdown. ALPL activity in PXE fibroblasts was studied using ALPL stains. Results We demonstrate the upregulation of the BMP2-SMADs-RUNX2 and TGFβ-2-SMAD2/3 pathway, co-localizing with the mineralization sites, and the involvement of MSX2-canonical Wnt signalling. Further, we show that apoptosis is also involved in PXE with activation of Caspases and BCL-2. In contrast to vascular calcification, neither the other BMPs and TGFβs nor endoplasmic reticulum stress pathways seem to be perturbed in PXE. Conclusions Our study shows that we cannot simply extrapolate knowledge on cell signalling in vascular soft tissue calcification to a multisystem ectopic mineralisation disease as PXE. Contrary, we demonstrate a specific set of perturbed signalling pathways in PXE patients and the knock-out mouse model. Based on our findings and previously reported data, we propose a preliminary cell model of ECM calcification in PXE.
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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. Am J Pathol 2014; 184:159-70. [PMID: 24479134 PMCID: PMC3873484 DOI: 10.1016/j.ajpath.2013.09.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Prunier F, Terrien G, Le Corre Y, Apana ALY, Bière L, Kauffenstein G, Furber A, Bergen AAB, Gorgels TGMF, Le Saux O, Leftheriotis G, Martin L. Pseudoxanthoma elasticum: cardiac findings in patients and Abcc6-deficient mouse model. PLoS One 2013; 8:e68700. [PMID: 23935882 PMCID: PMC3720798 DOI: 10.1371/journal.pone.0068700] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/31/2013] [Indexed: 01/01/2023] Open
Abstract
Background Pseudoxanthoma elasticum (PXE), caused by mutations in the ABCC6 gene, is a rare multiorgan disease characterized by the mineralization and fragmentation of elastic fibers in connective tissue. Cardiac complications reportedly associated with PXE are mainly based on case reports. Methods A cohort of 67 PXE patients was prospectively assessed. Patients underwent physical examination, electrocardiogram, transthoracic echocardiography, cardiac magnetic resonance imaging (CMR), treadmill testing, and perfusion myocardial scintigraphy (SPECT). Additionally, the hearts of a PXE mouse models (Abcc6−/−) and wild-type controls (WT) were analyzed. Results Three patients had a history of proven coronary artery disease. In total, 40 patients underwent exercise treadmill tests, and 28 SPECT. The treadmill tests were all negative. SPECT showed mild perfusion abnormalities in two patients. Mean left ventricular (LV) dimension and function values were within the normal range. LV hypertrophy was found in 7 (10.4%) patients, though the hypertrophy etiology was unknown for 3 of those patients. Echocardiography revealed frequent but insignificant mitral and tricuspid valvulopathies. Mitral valve prolapse was present in 3 patients (4.5%). Two patients exhibited significant aortic stenosis (3.0%). While none of the functional and histological parameters diverged significantly between the Abcc6−/− and WT mice groups at age of 6 and 12 months, the 24-month-old Abcc6−/− mice developed cardiac hypertrophy without contractile dysfunction. Conclusions Despite sporadic cases, PXE does not appear to be associated with frequent cardiac complications. However, the development of cardiac hypertrophy in the 24-month-old Abcc6−/− mice suggests that old PXE patients might be prone to developing late cardiopathy.
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Pomozi V, Le Saux O, Brampton C, Apana A, Iliás A, Szeri F, Martin L, Monostory K, Paku S, Sarkadi B, Szakács G, Váradi A. ABCC6 is a basolateral plasma membrane protein. Circ Res 2013; 112:e148-51. [PMID: 23625951 DOI: 10.1161/circresaha.111.300194] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE ABCC6 plays a crucial role in ectopic calcification; mutations of the gene cause pseudoxanthoma elasticum and general arterial calcification of infancy. To elucidate the role of ABCC6 in cellular physiology and disease, it is crucial to establish the exact subcellular localization of the native ABCC6 protein. OBJECTIVE In a recent article in Circulation Research, ABCC6 was reported to localize to the mitochondria-associated membrane and not the plasma membrane. As the suggested mitochondrial localization is inconsistent with published data and the presumed role of ABCC6, we performed experiments to determine the cellular localization of ABCC6 in its physiological environment. METHODS AND RESULTS We performed immunofluorescent labeling of frozen mouse and human liver sections, as well as primary hepatocytes. We used several different antibodies recognizing human and mouse ABCC6. Our results unequivocally show that ABCC6 is in the basolateral membrane of hepatocytes and is not associated with the mitochondria, mitochondria-associated membrane, or the endoplasmic reticulum. CONCLUSIONS Our findings support the model that ABCC6 is in the basolateral membrane, mediating the sinusoidal efflux of a metabolite from the hepatocytes to systemic circulation.
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Affiliation(s)
- Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
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Arányi T, Bacquet C, de Boussac H, Ratajewski M, Pomozi V, Fülöp K, Brampton CN, Pulaski L, Le Saux O, Váradi A. Transcriptional regulation of the ABCC6 gene and the background of impaired function of missense disease-causing mutations. Front Genet 2013; 4:27. [PMID: 23483032 PMCID: PMC3593682 DOI: 10.3389/fgene.2013.00027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 02/20/2013] [Indexed: 12/11/2022] Open
Abstract
The human ATP-binding cassette family C member 6 (ABCC6) gene encodes an ABC transporter protein expressed primarily in the liver and to a lesser extent in the kidneys and the intestines. We review here the mechanisms of this restricted tissue-specific expression and the role of hepatocyte nuclear factor 4α which is responsible for the expression pattern. Detailed analyses uncovered further regulators of the expression of the gene pointing to an intronic primate-specific regulator region, an activator of the expression of the gene by binding CCAAT/enhancer-binding protein beta, which interacts with other proteins acting in the proximal promoter. This regulatory network is affected by various environmental stimuli including oxidative stress and the extracellular signal-regulated protein kinases 1 and 2 pathway. We also review here the structural and functional consequences of disease-causing missense mutations of ABCC6. A significant clustering of the missense disease-causing mutations was found at the domain–domain interfaces. This clustering means that the domain contacts are much less permissive to amino acid replacements than the rest of the protein. We summarize the experimental methods resulting in the identification of mutants with preserved transport activity but failure in intracellular targeting. These mutants are candidates for functional rescue by chemical chaperons. The results of such research can provide the basis of future allele-specific therapy of ABCC6-mediated disorders like pseudoxanthoma elasticum or the generalized arterial calcification in infancy.
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Affiliation(s)
- Tamás Arányi
- Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Budapest, Hungary
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Lefthériotis G, Omarjee L, Le Saux O, Henrion D, Abraham P, Prunier F, Willoteaux S, Martin L. The vascular phenotype in Pseudoxanthoma elasticum and related disorders: contribution of a genetic disease to the understanding of vascular calcification. Front Genet 2013; 4:4. [PMID: 23408347 PMCID: PMC3569880 DOI: 10.3389/fgene.2013.00004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/04/2013] [Indexed: 01/28/2023] Open
Abstract
Vascular calcification is a complex and dynamic process occurring in various physiological conditions such as aging and exercise or in acquired metabolic disorders like diabetes or chronic renal insufficiency. Arterial calcifications are also observed in several genetic diseases revealing the important role of unbalanced or defective anti- or pro-calcifying factors. Pseudoxanthoma elasticum (PXE) is an inherited disease (OMIM 264800) characterized by elastic fiber fragmentation and calcification in various soft conjunctive tissues including the skin, eyes, and arterial media. The PXE disease results from mutations in the ABCC6 gene, encoding an ATP-binding cassette transporter primarily expressed in the liver, kidneys suggesting that it is a prototypic metabolic soft-tissue calcifying disease of genetic origin. The clinical expression of the PXE arterial disease is characterized by an increased risk for coronary (myocardial infarction), cerebral (aneurysm and stroke), and lower limb peripheral artery disease. However, the structural and functional changes in the arterial wall induced by PXE are still unexplained. The use of a recombinant mouse model inactivated for the Abcc6 gene is an important tool for the understanding of the PXE pathophysiology although the vascular impact in this model remains limited to date. Overlapping of the PXE phenotype with other inherited calcifying diseases could bring important informations to our comprehension of the PXE disease.
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Affiliation(s)
- Georges Lefthériotis
- PXE Health and Research Centre, University Hospital of Angers Angers, France ; L'UNAM, UMR CNRS 6214 - Inserm 1083, Medical School of Angers Angers, France
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Le Saux O, Martin L, Aherrahrou Z, Leftheriotis G, Váradi A, Brampton CN. The molecular and physiological roles of ABCC6: more than meets the eye. Front Genet 2012; 3:289. [PMID: 23248644 PMCID: PMC3520154 DOI: 10.3389/fgene.2012.00289] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 11/23/2012] [Indexed: 12/30/2022] Open
Abstract
Abnormal mineralization occurs in the context of several common conditions, including advanced age, diabetes, hypercholesterolemia, chronic renal failure, and certain genetic conditions. Metabolic, mechanical, infectious, and inflammatory injuries promote ectopic mineralization through overlapping yet distinct molecular mechanisms of initiation and progression. The ABCC6 protein is an ATP-dependent transporter primarily found in the plasma membrane of hepatocytes. ABCC6 exports unknown substrates from the liver presumably for systemic circulation. ABCC6 deficiency is the primary cause for chronic and acute forms of ectopic mineralization described in diseases such as pseudoxanthoma elasticum (PXE), β-thalassemia, and generalized arterial calcification of infancy (GACI) in humans and dystrophic cardiac calcification (DCC) in mice. These pathologies are characterized by mineralization of cardiovascular, ocular, and dermal tissues. PXE and to an extent GACI are caused by inactivating ABCC6 mutations, whereas the mineralization associated with β-thalassemia patients derives from a liver-specific change in ABCC6 expression. DCC is an acquired phenotype resulting from cardiovascular insults (ischemic injury or hyperlipidemia) and secondary to ABCC6 insufficiency. Abcc6-deficient mice develop ectopic calcifications similar to both the human PXE and mouse DCC phenotypes. The precise molecular and cellular mechanism linking deficient hepatic ABCC6 function to distal ectopic mineral deposition is not understood and has captured the attention of many research groups. Our previously published work along with that of others show that ABCC6 influences other modulators of calcification and that it plays a much greater physiological role than originally thought.
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Affiliation(s)
- Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii Honolulu, HI, USA
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Le Corre Y, Le Saux O, Froeliger F, Libouban H, Kauffenstein G, Willoteaux S, Leftheriotis G, Martin L. Quantification of the calcification phenotype of Abcc6-deficient mice with microcomputed tomography. Am J Pathol 2012; 180:2208-13. [PMID: 22469843 DOI: 10.1016/j.ajpath.2012.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 01/27/2012] [Accepted: 02/02/2012] [Indexed: 11/29/2022]
Abstract
Pseudoxanthoma elasticum in humans and dystrophic cardiac calcification in mice are heritable disorders characterized by dystrophic calcification of soft connective tissues related to the defective function of the ABCC6 (human)/Abcc6 (mouse) transporter. Of particular interest is the finding of calcified vibrissae in Abcc6(-/-) mice, which facilitates the study of dystrophic calcification by histological techniques. We aimed to determine whether mice prone to dystrophic cardiac calcification (C3H/HeOuJ and DBA/2J strains) presented similar vibrissae changes and to evaluate the value of microcomputed tomography to quantify the extent of mystacial vibrissae calcifications. These calcifications were absent in DBA/2J and C57BL/6J control mice. In both Abcc6(-/-) and C3H/HeOuJ mice, calcifications progressed in a caudal-rostral direction with aging. However, the calcification process was delayed in C3H/HeOuJ mice, indicating an incomplete expression of the calcification phenotype. We also found that the calcification process in the cephalic region was not limited to mystacial vibrissae but was also present in other periorbital sensorial vibrissae. The vibrissae calcification was circular and encompassed the medial region of the vibrissae capsule, adjacent to the ring and cavernous sinuses (the areas adjacent to blood and lymphatic vessels). Collectively, our findings confirm that Abcc6 acts as an inhibitor of spontaneous chronic mineralization and that microcomputed tomography is a valuable noninvasive tool for the assessment of the calcification phenotype in Abcc6-deficient mice.
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Affiliation(s)
- Yannick Le Corre
- Integrated Neurovascular and Mitochondrial Biology, Angers School of Medicine, LUNAM University, Angers, France
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Lefthériotis G, Abraham P, Le Corre Y, Le Saux O, Henrion D, Ducluzeau PH, Prunier F, Martin L. Relationship between ankle brachial index and arterial remodeling in pseudoxanthoma elasticum. J Vasc Surg 2011; 54:1390-4. [PMID: 21723076 DOI: 10.1016/j.jvs.2011.04.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/14/2011] [Accepted: 04/14/2011] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Pseudoxanthoma elasticum (PXE) is an inherited metabolic disease characterized by elastic fiber fragmentation and calcification in the cutaneous, ophthalmologic, and vascular tissues. Cardiovascular manifestations such as peripheral arterial disease (PAD) are frequent in PXE. Because of the changes in the elastic properties and medial calcification of the arterial wall in PXE, the impact of the arterial remodeling on the ankle brachial index (ABI), a well-established diagnostic method for the detection and follow-up of PAD, remains to be determined in this disease. METHODS This was a cross-sectional, comparative, open study, which took place at the PXE Consultation Center, University Hospital of Angers. The subjects were 53 patients (mean age, 49 ± 14 years; 35 females) with PXE clinically proven on the basis of established criteria (skin changes, angioid streaks, and skin biopsy). The ABI at rest, symptoms of intermittent claudication (IC), carotid intima-media thickness (IMT), carotid-femoral pulse wave velocity (c-f PWV), compliance (CC), and β stiffness index were measured in a single-center cohort. RESULTS Forty-five percent of the PXE patients had an ABI ≤0.90, but only one patient had an ABI >1.40. IC was found in 23% of the patients with an ABI ≤0.90. There were no significant differences between the patients with a low and normal ABI in terms of IMT (P = .566) or β stiffness index (P = .194), but differences were significant for c-f PWV (P = .010) and CC (P = .011). Adjusted multivariate linear regression for the Framingham-Laurier score showed that patients with a low ABI had less compliant carotid arteries (B = 0.318, P = .039). CONCLUSIONS PAD detected by a low ABI is very frequent in PXE, although with limited prevalence of symptomatic claudication. Unexpectedly, ABI was low in such calcifying PAD and associated with lower CC, independently of atherosclerosis risk factors. These findings demonstrate that PXE represents a unique monogenic model of PAD in which the specific arterial wall remodeling could change the diagnostic value of the ABI to detect PAD.
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Brampton C, Yamaguchi Y, Vanakker O, Van Laer L, Chen LH, Thakore M, De Paepe A, Pomozi V, Szabó PT, Martin L, Váradi A, Le Saux O. Vitamin K does not prevent soft tissue mineralization in a mouse model of pseudoxanthoma elasticum. Cell Cycle 2011; 10:1810-20. [PMID: 21597330 DOI: 10.4161/cc.10.11.15681] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a heritable disease characterized by calcified elastic fibers in cutaneous, ocular, and vascular tissues. PXE is caused by mutations in ABCC6, which encodes a protein of the ATP-driven organic anion transporter family. The inability of this transporter to secrete its substrate into the circulation is the likely cause of PXE. Vitamin K plays a role in the regulation of mineralization processes as a co-factor in the carboxylation of calcification inhibitors such as Matrix Gla Protein (MGP). Vitamin K precursor or a conjugated form has been proposed as potential substrate(s) for ABCC6. We investigated whether an enriched diet of vitamin K1 or vitamin K2 (MK4) could stop or slow the disease progression in Abcc6 (-/-) mice. Abcc6 (-/-) mice were placed on a diet of either vitamin K1 or MK4 at 5 or 100 mg/kg at prenatal, 3 weeks or 3 months of age. Disease progression was quantified by measuring the calcium content of one side of the mouse muzzle skin and histological staining for calcium of the opposing side. Raising the vitamin K1 or MK4 content of the diet increased the concentration of circulating MK4 in the serum. However, this increase did not significantly affect the MGP carboxylation status or reduce its abnormal abundance, the total calcium content or the pathologic calcification in the whiskers of the 3 treatment groups compared to controls. Our findings showed that raising the dietary intake of vitamin K1 or MK4 was not beneficial in the treatment of PXE and suggested that the availability of vitamin K may not be a limiting factor in this pathology.
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Lefthériotis G, Vanakker O, Le Saux O, Martin L. Reply to the article of C. Markello et al. entitled "Vascular pathology of medial arterial calcifications in NT5E deficiency: Implications for the role of adenosine in pseudoxanthoma elasticum". Mol Genet Metab 2011; 103:199-200. [PMID: 21497121 PMCID: PMC5542055 DOI: 10.1016/j.ymgme.2011.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 03/14/2011] [Indexed: 11/20/2022]
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Martin L, Douet V, VanWart CM, Heller MB, Le Saux O. A mouse model of β-thalassemia shows a liver-specific down-regulation of Abcc6 expression. Am J Pathol 2011; 178:774-83. [PMID: 21281810 DOI: 10.1016/j.ajpath.2010.10.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/25/2010] [Accepted: 10/05/2010] [Indexed: 01/14/2023]
Abstract
β-Thalassemia and pseudoxanthoma elasticum (PXE) are distinct genetic disorders. Yet, a dystrophic mineralization phenotype similar to PXE has frequently been associated with β-thalassemia or sickle cell anemia patients of Mediterranean descent. These calcifications are clinically and structurally identical to inherited PXE. As we previously excluded the presence of PXE-causing mutations in the ABCC6 gene of β-thalassemia patients with PXE manifestations, we hypothesized that a molecular mechanism independent of gene mutations either altered the ABCC6 gene expression or disrupted the biologic properties of its product in the liver or kidneys, which are the tissues with the highest levels of expression. To test this possibility, we investigated Abcc6 synthesis in the liver and kidneys of a β-thalassemia mouse model (Hbb(th3/+)). We found a progressive liver-specific down-regulation of the Abcc6 gene expression and protein levels by quantitative PCR, Western blotting, and immunofluorescence. The levels of Abcc6 protein decreased significantly at 6 months of age and stabilized at 10 months and older ages at ∼25% of the wild-type protein levels. We studied the transcriptional regulation of the Abcc6 gene in wild-type and Hbb(th3/+) mice, and we identified the erythroid transcription factor NF-E2 as the main cause of the transcriptional down-regulation using transcription factor arrays and chromatin immunoprecipitation. The Hbb(th3/+) mice did not develop spontaneous calcification as seen in the Abcc6(-/-) mice probably because the Abcc6 protein decrease occurred late in life and was probably insufficient to promote mineralization in the Hbb(th3/+) mouse C57BL/6J genetic background. Nevertheless, our result suggested that a similar decrease of ABCC6 expression occurs in the liver of β-thalassemia patients and may be responsible for their frequent PXE-like manifestations.
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Affiliation(s)
- Ludovic Martin
- Department of Dermatology, University Hospital of Angers, Angers, France
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Le Saux O, Teeters K, Choi JW, Starcher B, Davis EC, Jourdan Le Saux C. The role of caveolin-1 in pulmonary matrix remodeling. Matrix Biol 2008. [DOI: 10.1016/j.matbio.2008.09.234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Martin L, Maître F, Bonicel P, Daudon P, Verny C, Bonneau D, Le Saux O, Chassaing N. Heterozygosity for a Single Mutation in the ABCC6 Gene May Closely Mimic PXE. ACTA ACUST UNITED AC 2008; 144:301-6. [DOI: 10.1001/archderm.144.3.301] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Douet V, Heller MB, Le Saux O. DNA methylation and Sp1 binding determine the tissue-specific transcriptional activity of the mouse Abcc6 promoter. Biochem Biophys Res Commun 2006; 354:66-71. [PMID: 17214963 PMCID: PMC1876782 DOI: 10.1016/j.bbrc.2006.12.151] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 12/15/2006] [Indexed: 11/20/2022]
Abstract
The gene encoding the ABCC6 protein, an ABC transporter of the multidrug resistance-associated protein (MRP), is mainly expressed in liver and kidney. Mutations in ABCC6 are responsible for the development of the pseudoxanthoma elasticum (PXE) phenotype. PXE is a recessive disease characterized by the calcification of elastic fibers resulting in dermal, vascular, and ocular clinical manifestations. The physiological function of ABCC6 and the rodent orthologs Abcc6 is unknown and their precise relationship to elastic fibers is only a matter of speculation. Despite several studies focused on the transcriptional regulation of ABCC6/Abcc6, the molecular signals conferring the tissue-specificity to the ABCC6/Abcc6 expression are not well defined. In this report, we determined the level of the mouse Abcc6 promoter methylation in tissues with low level of expression (tail extremity and skin), intermediate (kidney), and high level of expression (liver). We observed that high and moderate levels of methylation correlated with low levels of Abcc6 expression. Moreover, we determined that CpG methylation of the Abcc6 proximal promoter region was interfering with the binding of the Sp1 transcription factor thereby inhibiting Sp1-dependent transactivation. Thus, our data provide the first direct evidence that an epigenetic mechanism regulates the binding of transcription factor Sp1 to the proximal promoter and participates in the tissue-specific expression control of the mouse Abcc6 gene.
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Affiliation(s)
- Vanessa Douet
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
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Douet V, VanWart CM, Heller MB, Reinhard S, Le Saux O. HNF4alpha and NF-E2 are key transcriptional regulators of the murine Abcc6 gene expression. ACTA ACUST UNITED AC 2006; 1759:426-36. [PMID: 16997394 PMCID: PMC1876778 DOI: 10.1016/j.bbaexp.2006.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 08/04/2006] [Accepted: 08/06/2006] [Indexed: 12/30/2022]
Abstract
Mutations in an ABC transporter gene called ABCC6 are responsible for pseudoxanthoma elasticum (PXE), a rare heritable disease characterized by elastic fiber calcification in skin, ocular and vascular tissues. The presumed function of this ABC transporter is to export metabolites from polarized cells. However, the endogenous substrate(s) are unknown and the exact relationship with elastic fibers is unclear. As ABCC6 is only expressed at high level in liver and kidneys, tissues seemingly unrelated to the PXE phenotype, we explored the transcriptional regulation of the murine Abcc6 gene to define the transcriptional signal conferring tissue specificity and to gather clues on its possible biological function. We cloned 2.9 kb of the mAbcc6 5'-flanking region and several deletion constructs linked to a luciferase reporter gene. We delineated a proximal promoter and a liver-specific enhancer region. We also demonstrated that the proximal region is a TATA-less promoter requiring an intact CCAAT-box and Sp1 binding for its basal activity. By using reporter assays and chromatin immunoprecipitations, we showed that HNF4alpha and surprisingly, NF-E2, enhanced the mAbcc6 promoter activity. The involvement of both HNF4alpha and NF-E2 in the mAbcc6 gene regulation suggests that Abcc6 might be involved in a detoxification processes related to hemoglobin or heme.
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Affiliation(s)
- Vanessa Douet
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, BSB 222, Honolulu, HI 96813, USA
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Le Saux O, Bunda S, VanWart CM, Douet V, Got L, Martin L, Hinek A. Serum factors from pseudoxanthoma elasticum patients alter elastic fiber formation in vitro. J Invest Dermatol 2006; 126:1497-505. [PMID: 16543900 PMCID: PMC5540375 DOI: 10.1038/sj.jid.5700201] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pseudoxanthoma elasticum (PXE) is a heritable disorder mainly characterized by calcified elastic fibers in cutaneous, ocular, and vascular tissues. PXE is caused by mutations in ABCC6, a gene encoding an ABC transporter predominantly expressed in liver and kidneys. The functional relationship between ABCC6 and elastic fiber calcification is unknown. We speculated that ABCC6 deficiency in PXE patients induces a persistent imbalance in circulating metabolite(s), which may impair the synthetic abilities of normal elastoblasts or specifically alter elastic fiber assembly. Therefore, we compared the deposition of elastic fiber proteins in cultures of fibroblasts derived from PXE and unaffected individuals. PXE fibroblasts cultured with normal human serum expressed and deposited increased amounts of proteins, but structurally normal elastic fibers. Interestingly, normal and PXE fibroblasts as well as normal smooth muscle cells deposited abnormal aggregates of elastic fibers when maintained in the presence of serum from PXE patients. The expression of tropoelastin and other elastic fiber-associated genes was not significantly modulated by the presence of PXE serum. These results indicated that certain metabolites present in PXE sera interfered with the normal assembly of elastic fibers in vitro and suggested that PXE is a primary metabolic disorder with secondary connective tissue manifestations.
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Affiliation(s)
- 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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Abstract
A significant number of patients diagnosed with beta-thalassaemia develop clinical and histopathological manifestations similar to those of an inherited disorder called Pseudoxanthoma elasticum (PXE). The inherited PXE is caused by mutations in the ATP-binding cassette, subfamily C (CFTR/MRP), member 6 (ABCC6) gene and is characterized by mineralized elastic fibres in dermal, vascular and ocular tissues. As no disease-causing variant was found in the ABCC6 gene of 10 beta-thalassaemia patients with a PXE-like phenotype, the present study suggests that the PXE-like symptoms in these beta-thalassaemic patients are not related to ABCC6 mutations.
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Affiliation(s)
- Naomi Hamlin
- Pacific Biomedical Research Center, University of Hawai'i, Honolulu, HI 96822, USA
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Beck K, Hayashi K, Nishiguchi B, Le Saux O, Hayashi M, Boyd CD. The distribution of Abcc6 in normal mouse tissues suggests multiple functions for this ABC transporter. J Histochem Cytochem 2003; 51:887-902. [PMID: 12810839 DOI: 10.1177/002215540305100704] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We have studied the tissue distribution of Abcc6, a member of the ABC transmembrane transporter subfamily C, in normal C57BL/6 mice. RNase protection assays revealed that although almost all tissues studied contained detectable levels of the mRNA encoding Abcc6, the highest levels of Abcc6 mRNA were found in the liver. In situ hybridization (ISH) demonstrated abundant Abcc6 mRNA in epithelial cells from a variety of tissues, including hepatic parenchymal cells, bile duct epithelia, kidney proximal tubules, mucosa and gland cells of the stomach, intestine, and colon, squamous epithelium of the tongue, corneal epithelium of the eye, keratinocytes of the skin, and tracheal and bronchial epithelium. Furthermore, we detected Abcc6 mRNA in arterial endothelial cells, smooth muscle cells of the aorta and myocardium, in circulating leukocytes, lymphocytes in the thymus and lymph nodes, and in neurons of the brain, spinal cord, and the specialized neurons of the retina. Immunohistochemical analysis using a polyclonal Abcc6 rabbit antibody confirmed the tissue distribution of Abcc6 suggested by our ISH studies and revealed the cellular localization of Abcc6 in the basolateral plasma membrane in the epithelial cells of proximal convoluted tubules in the kidney. Although the function of Abcc6 is unknown, mutations in the human ABCC6 gene result in a heritable disorder of connective tissue called pseudoxanthoma elasticum (PXE). Our results demonstrating the presence of Abcc6 in epithelial and endothelial cells in a variety of tissues, including those tissues affected in PXE patients, suggest a possible role for Abcc6 in the normal assembly of extracellular matrix components. However, the presence of Abcc6 in neurons and leukocytes, two cell populations not associated with connective tissue, also suggests a more complex multifunctional role for Abcc6.
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Affiliation(s)
- Konstanze Beck
- Lab of Matrix Pathobiology, The Pacific Biomedical Research Center, University of Hawai'i, 1993 East-West Road, Honolulu, HI 96822, USA
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Le Saux O, Beck K, Sachsinger C, Treiber C, Göring HHH, Curry K, Johnson EW, Bercovitch L, Marais AS, Terry SF, Viljoen DL, Boyd CD. Evidence for a founder effect for pseudoxanthoma elasticum in the Afrikaner population of South Africa. Hum Genet 2002; 111:331-8. [PMID: 12384774 DOI: 10.1007/s00439-002-0808-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2002] [Accepted: 07/08/2002] [Indexed: 10/27/2022]
Abstract
Pseudoxanthoma elasticum (PXE) is a heritable elastic tissue disorder recently shown to be attributable to mutations in the ABCC6 ( MRP6) gene. Whereas PXE has been identified in all ethnic groups studied to date, the prevalence of this disease in various populations is uncertain, although often assumed to be similar. A notable exception however is the prevalence of PXE among South African Afrikaners. A previous report has suggested that a founder effect may explain the higher prevalence of PXE in Afrikaners, a European-derived population that first settled in South Africa in the 17th century. To investigate this hypothesis, we performed haplotype and mutational analysis of DNA from 24 South African families of Afrikaner, British and Indian descent. Among the 17 Afrikaner families studied, three common haplotypes and six different disease-causing variants were identified. Three of these mutant alleles were missense variants, two were nonsense mutations and one was a single base-pair insertion. The most common variant accounted for 53% of the PXE alleles, whereas other mutant alleles appeared at lower frequencies ranging from 3% to 12%. Haplotype analysis of the Afrikaner families showed that the three most frequent mutations were identical-by-descent, indicating a founder origin of PXE in this population.
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Affiliation(s)
- Olivier Le Saux
- Pacific Biomedical Research Center, University of Hawai'i, Honolulu, Hawaii, USA
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Iliás A, Urbán Z, Seidl TL, Le Saux O, Sinkó E, Boyd CD, Sarkadi B, Váradi A. Loss of ATP-dependent transport activity in pseudoxanthoma elasticum-associated mutants of human ABCC6 (MRP6). J Biol Chem 2002; 277:16860-7. [PMID: 11880368 DOI: 10.1074/jbc.m110918200] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the ABCC6 (MRP6) gene cause pseudoxanthoma elasticum (PXE), a rare heritable disorder resulting in the calcification of elastic fibers. In the present study a cDNA encoding a full-length normal variant of ABCC6 was amplified from a human kidney cDNA library, and the protein was expressed in Sf9 insect cells. In isolated membranes ATP binding as well as ATP-dependent active transport by ABCC6 was demonstrated. We found that glutathione conjugates, including leukotriene C(4) and N-ethylmaleimide S-glutathione (NEM-GS), were actively transported by human ABCC6. Organic anions (probenecid, benzbromarone, indomethacin), known to interfere with glutathione conjugate transport of human ABCC1 and ABCC2, inhibited the ABCC6-mediated NEM-GS transport in a specific manner, indicating that ABCC6 has a unique substrate specificity. We have also expressed three missense mutant forms of ABCC6, which have recently been shown to cause PXE. MgATP binding was normal in these proteins; ATP-dependent NEM-GS or leukotriene C(4) transport, however, was abolished. Our data indicate that human ABCC6 is a primary active transporter for organic anions. In the three ABCC6 mutant forms examined, the loss of transport activity suggests that these mutations result in a PXE phenotype through a direct influence on the transport activity of this ABC transporter.
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Affiliation(s)
- Attila Iliás
- Institute of Enzymology, Hungarian Academy of Sciences, 1113 Budapest, Hungary
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Le Saux O, Pope M, Urban Z, Csiszar K, Struk B, Terry S, Bercovitch L, Magro C, Lebwohl M, Uitto J, Lindpaintner K, Boyd CD. Pseudoxanthsoma elasticum: A sib pair and haplotype analysis at 16p reveals a largely dominant disorder with variable penetrance in unrelated families from the United Kingdom and North America. J Dermatol Sci 1998. [DOI: 10.1016/s0923-1811(98)83896-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Le Saux O, Urban Z, Csiszar K, Struk B, Terry S, Bercovitch L, Magro C, Pope M, Lebwohl M, Uitto J, Lindpaintner K, Boyd CD. Pseudoxanthoma elasticum: Confirmation of linkage to 16p13.1 and demonstration of a largely recessive inheritance in unrelated families from the United Kingdom and North America. J Dermatol Sci 1998. [DOI: 10.1016/s0923-1811(98)83849-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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