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. 2014 Aug 29;19(4):517–526. doi: 10.2478/s11658-014-0208-2

Dysregulation of gene expression in ABCC6 knockdown HepG2 cells

Rocchina Miglionico 1, Maria Francesca Armentano 1, Monica Carmosino 1, Antonella Maria Salvia 1, Flavia Cuviello 1, Faustino Bisaccia 1,✉, Angela Ostuni 1
PMCID: PMC6275862  PMID: 25169437

Abstract

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

Keywords: ABCC6, Knockdown, HepG2 cells, Gene expression, Mineralization, TNAP, NT5E, OPN, Fetuin A

Full Text

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Abbreviations used

ABCC6

ATP-binding cassette, sub-family C, member 6

ACDC

arterial calcifications due to deficiency in CD73

CD73

cluster of differentiation 73

DCC

dystrophic cardiac calcification

Enpp1

ecto-nucleotide pyrophosphatase/phosphodiesterase type I

GACI

generalized arterial calcification of infancy

MRP

multidrug resistance protein

NT5E

ecto-5’-nucleotidase

OPN

osteopontin

PXE

pseudoxanthoma elasticum

TNAP

tissue-nonspecific alkaline phosphatase

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