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Saha, S.* ; Bornstein, S.R.* ; Graessler, J.* ; Kopprasch, S.*

Very-low-density lipoprotein mediates transcriptional regulation of aldosterone synthase in human adrenocortical cells through multiple signaling pathways.

Cell Tissue Res. 348, 71-80 (2012)
DOI Verlagsversion bestellen
Diabetic dyslipidemia is characterized by increased circulatory very-low-density lipoprotein (VLDL) levels. Aldosterone, apart from its role in fluid and electrolyte homeostasis, has also been implicated in insulin resistance and myocardial fibrosis. The impact of VLDL as a potential risk factor for aldosterone-mediated cardiovascular injury in diabetes mellitus, however, remains to be investigated. We have therefore studied native and modified VLDL-mediated steroidogenesis and its underlying molecular mechanisms in human adrenocortical carcinoma cells, NCI H295R. Native VLDL (natVLDL), isolated from healthy volunteers, was subjected to in vitro modification with glucose (200 mmol/l) or sodium hypochlorite (1.5 mmol/l) for preparation of glycoxidized and oxidized VLDL, respectively. VLDL treatment induced steroidogenesis in both a concentration- and time-dependent manner. Native and glycoxidized VLDL (50 μg/ml) were almost two-fold more potent in adrenocortical aldosterone release than angiotensin II (100 nmol/l). These forms of VLDL significantly augmented transcriptional regulation of aldosterone synthase (Cyp11B2), partially through scavenger receptor class B type I, as evident from the effect of BLT-1. In contrast to glycoxidized VLDL, oxidized VLDL significantly attenuated the stimulatory effect of natVLDL on adrenocortical hormone synthesis. Moreover, treatment with specific pharmacological inhibitors (H89, U0126, AG490) provided supporting evidence that VLDL, irrespective of modification, presumably recruited PKA, ERK1/2 and Jak-2 for steroid hormone release through modulation of Cyp11B2 mRNA level. In conclusion, this study demonstrates a novel insight into intracellular mechanism of VLDL-mediated aldosterone synthesis through transcriptional regulation of steroidogenic acute regulatory protein (StAR) and Cyp11B2 expression in human adrenocortical carcinoma cell line.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
ISSN (print) / ISBN 0044-3794
e-ISSN 1432-0878
Quellenangaben Band: 348, Heft: 1, Seiten: 71-80 Artikelnummer: , Supplement: ,
Verlag Springer
Begutachtungsstatus Peer reviewed
Institut(e) Institute for Pancreatic Beta Cell Research (IPI)