Dysregulation of gene expression in ABCC6 knockdown HepG2 cells

Miglionico, Rocchina; Armentano, Maria Francesca; Carmosino, Monica; Salvia, Antonella Maria; Cuviello, Flavia; Bisaccia, Faustino; Ostuni, Angela

doi:10.2478/s11658-014-0208-2

Cited by 30 publications

(52 citation statements)

References 26 publications

(31 reference statements)

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“…We performed all experiments in stable ABCC6 knockdown HepG2 cells that had been previously generated and studied [20]. Unexpectedly, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

ABCC6 knockdown in HepG2 cells induces a senescent-like cell phenotype

et al. 2017

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BackgroundPseudoxanthoma elasticum (PXE) is characterized by progressive ectopic mineralization of elastic fibers in dermal, ocular and vascular tissues. No effective treatment exists. It is caused by inactivating mutations in the gene encoding for the ATP-binding cassette, sub-family C member 6 transporter (ABCC6), which is mainly expressed in the liver. The ABCC6 substrate (s) and the PXE pathomechanism remain unknown. Recent studies have shown that overexpression of ABCC6 in HEK293 cells results in efflux of ATP, which is rapidly converted into nucleoside monophosphates and pyrophosphate (PPi). Since the latter inhibits mineralization, it was proposed that the absence of circulating PPi in PXE patients results in the characteristic ectopic mineralization. These studies also demonstrated that the presence of ABCC6 modifies cell secretory activity and suggested that ABCC6 can change the cell phenotype.MethodsStable ABCC6 knockdown HepG2 clones were generated using small hairpin RNA (shRNA) technology. The intracellular glutathione and ROS levels were determined. Experiments using cell cycle analysis, real-time PCR and western blot were performed on genes involved in the senescence phenotype.ResultsTo shed light on the physiological role of ABCC6, we focused on the phenotype of HepG2 cells that lack ABCC6 activity. Interestingly, we found that ABCC6 knockdown HepG2 cells show: 1) intracellular reductive stress; 2) cell cycle arrest in G1 phase; 3) upregulation of p21Cip p53 independent; and 4) downregulation of lamin A/C.ConclusionsThese findings show that the absence of ABCC6 profoundly changes the HepG2 phenotype, suggesting that the PXE syndrome is a complex metabolic disease that is not exclusively related to the absence of pyrophosphate in the bloodstream.

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“…We performed all experiments in stable ABCC6 knockdown HepG2 cells that had been previously generated and studied [20]. Unexpectedly, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

ABCC6 knockdown in HepG2 cells induces a senescent-like cell phenotype

et al. 2017

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“…delivery. Indeed, ABCC6 knockdown causes an increase of TNAP in an in vitro model, 42 and there was a possibility that this could also happen in vivo and affect PPi clearance in mice. We found that a 112 mmol/kg (50 mg/kg) injection produced after 5 minutes a plasma concentration of approximately 14 mmol/L, which corresponds to a bioavailability of approximately 0.5%.…”

Section: Ppi Administrationmentioning

confidence: 99%

Pyrophosphate Supplementation Prevents Chronic and Acute Calcification in ABCC6-Deficient Mice

Pomozi

Brampton

Wetering

et al. 2017

The American Journal of Pathology

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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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“…Considering the inheritable calcification syndromes resulting from dysfunctional ABCC6, this transporter is now viewed as a key player in ectopic mineralization pathologies, but it is unclear how ABCC6 contributes to this process. Nonetheless, the latest studies indicate that loss of ABCC6 alters gene expression profiles in a way that mineralization-promoting genes (tissue-nonspecific alkaline phosphatase ( TNAP ), bone morphogenetic protein ( BMP )) are upregulated while the expression of genes with the opposite effect (ecto-5′-nucleotidase ( NT5E ), Fetuin A and Osteopontin ) is decreased both in vitro [ 81 ] and in vivo [ 82 ]. Moreover, recent in silico studies have suggested new substrate candidates for ABCC6 that hopefully will be evaluated experimentally in vitro and in vivo in the near future [ 83 ].…”

Section: Abc Transporters In the Regulation Of Endothelial Functiomentioning

confidence: 99%

ABC Transport Proteins in Cardiovascular Disease—A Brief Summary

Schumacher

Benndorf

2017

Molecules

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Adenosine triphosphate (ATP)-binding cassette (ABC) transporters may play an important role in the pathogenesis of atherosclerotic vascular diseases due to their involvement in cholesterol homeostasis, blood pressure regulation, endothelial function, vascular inflammation, as well as platelet production and aggregation. In this regard, ABC transporters, such as ABCA1, ABCG5 and ABCG8, were initially found to be responsible for genetically-inherited syndromes like Tangier diseases and sitosterolemia. These findings led to the understanding of those transporter’s function in cellular cholesterol efflux and thereby also linked them to atherosclerosis and cardiovascular diseases (CVD). Subsequently, further ABC transporters, i.e., ABCG1, ABCG4, ABCB6, ABCC1, ABCC6 or ABCC9, have been shown to directly or indirectly affect cellular cholesterol efflux, the inflammatory response in macrophages, megakaryocyte proliferation and thrombus formation, as well as vascular function and blood pressure, and may thereby contribute to the pathogenesis of CVD and its complications. Furthermore, ABC transporters, such as ABCB1, ABCC2 or ABCG2, may affect the safety and efficacy of several drug classes currently in use for CVD treatment. This review will give a brief overview of ABC transporters involved in the process of atherogenesis and CVD pathology. It also aims to briefly summarize the role of ABC transporters in the pharmacokinetics and disposition of drugs frequently used to treat CVD and CVD-related complications.

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Dysregulation of gene expression in ABCC6 knockdown HepG2 cells

Cited by 30 publications

References 26 publications

ABCC6 knockdown in HepG2 cells induces a senescent-like cell phenotype

ABCC6 knockdown in HepG2 cells induces a senescent-like cell phenotype

Pyrophosphate Supplementation Prevents Chronic and Acute Calcification in ABCC6-Deficient Mice

ABC Transport Proteins in Cardiovascular Disease—A Brief Summary

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