scholarly journals Targeted Ablation of the Abcc6 Gene Results in Ectopic Mineralization of Connective Tissues

2005 ◽  
Vol 25 (18) ◽  
pp. 8299-8310 ◽  
Author(s):  
John F. Klement ◽  
Yasushi Matsuzaki ◽  
Qiu-Jie Jiang ◽  
Joseph Terlizzi ◽  
Hae Young Choi ◽  
...  
Keyword(s):  
Complex Disease ◽  
Soft Tissues ◽  
Subcutaneous Tissue ◽  
Pseudoxanthoma Elasticum ◽  
Connective Tissues ◽  
Alizarin Red ◽  
Arterial Blood ◽  
Ectopic Mineralization ◽  
Abcc6 Gene ◽  
Total Body

ABSTRACT Pseudoxanthoma elasticum (PXE), characterized by connective tissue mineralization of the skin, eyes, and cardiovascular system, is caused by mutations in the ABCC6 gene. ABCC6 encodes multidrug resistance-associated protein 6 (MRP6), which is expressed primarily in the liver and kidneys. Mechanisms producing ectopic mineralization as a result of these mutations remain unclear. To elucidate this complex disease, a transgenic mouse was generated by targeted ablation of the mouse Abcc6 gene. Abcc6 null mice were negative for Mrp6 expression in the liver, and complete necropsies revealed profound mineralization of several tissues, including skin, arterial blood vessels, and retina, while heterozygous animals were indistinguishable from the wild-type mice. Particularly striking was the mineralization of vibrissae, as confirmed by von Kossa and alizarin red stains. Electron microscopy revealed mineralization affecting both elastic structures and collagen fibers. Mineralization of vibrissae was noted as early as 5 weeks of age and was progressive with age in Abcc6 −/− mice but was not observed in Abcc6 +/− or Abcc6 +/+ mice up to 2 years of age. A total body computerized tomography scan of Abcc6 −/− mice revealed mineralization in skin and subcutaneous tissue as well as in the kidneys. These data demonstrate aberrant mineralization of soft tissues in PXE-affected organs, and, consequently, these mice recapitulate features of this complex disease.

Pseudoxanthoma elasticum with prominent arterial calcifications evoking CD73 deficiency

2019 ◽  
Vol 24 (5) ◽  
pp. 461-464 ◽  
Author(s):  
Magali Devriese ◽  
Anne Legrand ◽  
Marie-Cécile Courtois ◽  
Xavier Jeunemaitre ◽  
Juliette Albuisson
Keyword(s):  
Vascular Calcification ◽  
Pseudoxanthoma Elasticum ◽  
Arterial Calcification ◽  
Elastic Fibers ◽  
Connective Tissues ◽  
Tibial Arteries ◽  
Ectopic Mineralization ◽  
Abcc6 Gene ◽  
Next Generation Sequencing Ngs ◽  
Eye Lesions

Pseudoxanthoma elasticum (PXE) is a rare disorder characterized by skin, eye, and cardiovascular lesions due to ectopic mineralization and fragmentation of elastic fibers of connective tissues. We present an atypical case of PXE with diffuse vascular calcification and negligible skin and eye lesions. The patient was a 37-year-old man suffering from severe bilateral arterial calcifications in superficial femoral and posterior tibial arteries. Eye fundoscopy and skin examination were first considered normal. This phenotype suggested first the diagnosis of Arterial Calcification due to Deficiency of CD73 (ACDC) characterized by mutations in NT5E gene. However, we found two variants in ABCC6 gene, and no variant in NT5E. Skin reexamination revealed few lateral skin papules confined to the scalp. Phenotypic overlap was described in vascular calcification disorders, between GACI and PXE phenotypes, and we discuss here expansion of this overlap, including ACDC phenotype. Identification of these expanding and overlapping phenotypes was enabled by genetic screening of the corresponding genes, in a systematic approach. We propose to create a calcification next generation sequencing (NGS) panel with NT5E, GGCX, ENPP1, and ABCC6 genes to improve the molecular diagnosis of vascular calcification.

scholarly journals Structural and Functional Characterization of the ABCC6 Transporter in Hepatic Cells: Role on PXE, Cancer Therapy and Drug Resistance

2021 ◽  
Vol 22 (6) ◽  
pp. 2858
Author(s):  
Faustino Bisaccia ◽  
Prashant Koshal ◽  
Vittorio Abruzzese ◽  
Maria Antonietta Castiglione Morelli ◽  
Angela Ostuni
Keyword(s):  
Cancer Therapy ◽  
Functional Characterization ◽  
Physiological Role ◽  
Pseudoxanthoma Elasticum ◽  
Connective Tissues ◽  
Functional Studies ◽  
Extracellular Milieu ◽  
Hepatic Cells ◽  
Ectopic Mineralization ◽  
Anti Cancer

Pseudoxanthoma elasticum (PXE) is a complex autosomal recessive disease caused by mutations of ABCC6 transporter and characterized by ectopic mineralization of soft connective tissues. Compared to the other ABC transporters, very few studies are available to explain the structural components and working of a full ABCC6 transporter, which may provide some idea about its physiological role in humans. Some studies suggest that mutations of ABCC6 in the liver lead to a decrease in some circulating factor and indicate that PXE is a metabolic disease. It has been reported that ABCC6 mediates the efflux of ATP, which is hydrolyzed in PPi and AMP; in the extracellular milieu, PPi gives potent anti-mineralization effect, whereas AMP is hydrolyzed to Pi and adenosine which affects some cellular properties by modulating the purinergic pathway. Structural and functional studies have demonstrated that silencing or inhibition of ABCC6 with probenecid changed the expression of several genes and proteins such as NT5E and TNAP, as well as Lamin, and CDK1, which are involved in cell motility and cell cycle. Furthermore, a change in cytoskeleton rearrangement and decreased motility of HepG2 cells makes ABCC6 a potential target for anti-cancer therapy. Collectively, these findings suggested that ABCC6 transporter performs functions that modify both the external and internal compartments of the cells.

scholarly journals Dysregulation of gene expression in ABCC6 knockdown HepG2 cells

2014 ◽  
Vol 19 (4) ◽  
Author(s):  
Rocchina Miglionico ◽  
Maria Armentano ◽  
Monica Carmosino ◽  
Antonella Salvia ◽  
Flavia Cuviello ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Autosomal Recessive ◽  
Pseudoxanthoma Elasticum ◽  
Arterial Calcification ◽  
Elastic Fibers ◽  
Ectopic Calcification ◽  
Ectopic Mineralization ◽  
Abcc6 Gene ◽  
Basolateral Plasma Membrane

AbstractABCC6 protein is an ATP-dependent transporter that is mainly found in the basolateral plasma membrane of hepatocytes. ABCC6 deficiency is the primary cause of several forms of ectopic mineralization syndrome. Mutations in the human ABCC6 gene cause pseudoxanthoma elasticum (PXE), an autosomal recessive disease characterized by ectopic calcification of the elastic fibers in dermal, ocular and vascular tissues. Mutations in the mouse ABCC6 gene were also associated with dystrophic cardiac calcification. Reduced levels of ABCC6 protein were found in a β-thalassemic mouse model. Moreover, some cases of generalized arterial calcification in infancy are due to ABCC6 mutations. In order to study the role of ABCC6 in the pathogenesis of ectopic mineralization, the expressions of genes involved in this process were evaluated in HepG2 cells upon stable knockdown of ABCC6 by small hairpin RNA (shRNA) technology. ABCC6 knockdown in HepG2 cells causes a significant upregulation of the genes promoting mineralization, such as TNAP, and a parallel downregulation of genes with anti-mineralization activity, such as NT5E, Fetuin A and Osteopontin. Although the absence of ABCC6 has been already associated with ectopic mineralization syndromes, this study is the first to show a direct relationship between reduced ABCC6 levels and the expression of pro-mineralization genes in hepatocytes.

scholarly journals Therapeutics Development for Pseudoxanthoma Elasticum and Related Ectopic Mineralization Disorders: Update 2020

2020 ◽  
Vol 10 (1) ◽  
pp. 114
Author(s):  
Hongbin Luo ◽  
Qiaoli Li ◽  
Yi Cao ◽  
Jouni Uitto
Keyword(s):  
Plasma Levels ◽  
Autosomal Recessive Disorder ◽  
Pseudoxanthoma Elasticum ◽  
Calcium Hydroxyapatite ◽  
The Elderly ◽  
Arterial Calcification ◽  
Inorganic Pyrophosphate ◽  
Treatment Development ◽  
Arterial Blood ◽  
Ectopic Mineralization

Pseudoxanthoma elasticum (PXE), the prototype of heritable ectopic mineralization disorders, manifests with deposition of calcium hydroxyapatite crystals in the skin, eyes and arterial blood vessels. This autosomal recessive disorder, due to mutations in ABCC6, is usually diagnosed around the second decade of life. In the spectrum of heritable ectopic mineralization disorders are also generalized arterial calcification of infancy (GACI), with extremely severe arterial calcification diagnosed by prenatal ultrasound or perinatally, and arterial calcification due to CD73 deficiency (ACDC) manifesting with arterial and juxta-articular mineralization in the elderly; the latter disorders are caused by mutations in ENPP1 and NT5E, respectively. The unifying pathomechanistic feature in these three conditions is reduced plasma levels of inorganic pyrophosphate (PPi), a powerful endogenous inhibitor of ectopic mineralization. Several on-going attempts to develop treatments for these conditions, either with the goal to normalize PPi plasma levels or by means of preventing calcium hydroxyapatite deposition independent of PPi, are in advanced preclinical levels or in early clinical trials. This overview summarizes the prospects of treatment development for ectopic mineralization disorders, with PXE, GACI and ACDC as the target diseases, from the 2020 vantage point.

scholarly journals ABCC6, Pyrophosphate and Ectopic Calcification: Therapeutic Solutions

2021 ◽  
Vol 22 (9) ◽  
pp. 4555
Author(s):  
Briana K. Shimada ◽  
Viola Pomozi ◽  
Janna Zoll ◽  
Sheree Kuo ◽  
Ludovic Martin ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Genetic Disorders ◽  
Pseudoxanthoma Elasticum ◽  
Arterial Calcification ◽  
Ectopic Calcification ◽  
Direct Inhibition ◽  
Inorganic Pyrophosphate ◽  
Cardiovascular Tissues ◽  
Ectopic Mineralization

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.

scholarly journals Administration of vitamin K does not counteract the ectopic mineralization of connective tissues inAbcc6-/-mice, a model for pseudoxanthoma elasticum

Cell Cycle ◽  
2011 ◽  
Vol 10 (4) ◽  
pp. 701-707 ◽  
Author(s):  
Qiujie Jiang ◽  
Qiaoli Li ◽  
Alix E. Grand-Pierre ◽  
Leon J. Schurgers ◽  
Jouni Uitto
Keyword(s):  
Vitamin K ◽  
Pseudoxanthoma Elasticum ◽  
Connective Tissues ◽  
Ectopic Mineralization

A Comparative Study of the in vivo Distribution of 32P-Polyphosphates and 32P-Orthophosphate

1972 ◽  
Vol 11 (01) ◽  
pp. 70-78
Author(s):  
Esther Miller ◽  
Leopoldo Anghileri
Keyword(s):  
Radiation Dose ◽  
Comparative Study ◽  
Soft Tissues ◽  
Tumor Bearing ◽  
In Vivo Distribution ◽  
The Cross ◽  
Total Body

SummaryThe distribution of 32P-polyphosphates (lineal and cross-linked) and 32Porthophosphate in normal and tumor bearing animals has been studied. Differences between the cross-linked and the lineal form are related to a different degree of susceptibility to the hydrolysis by the phosphatases. In contrast to orthophosphate, the polyphosphates showed a lower accumulation in soft tissues which gives an advantageous reduction of the total body radiation dose.

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