7β-Hydroxycholesterol induces Ca2+ oscillations, MAP kinase activation and apoptosis in human aortic smooth muscle cells

Mikko P.S. Ares, M. Isabella Pörn-Ares, Sara Moses, Johan Thyberg, Lisa Juntti-Berggren, Per Olof Berggren, Anna Hultgårdh-Nilsson, Bengt Kallin, Jan Nilsson

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

In the present study, we characterize the early cytotoxic effects of 7β-hydroxycholesterol, a major cytotoxin in oxidized LDL, in human aortic smooth muscle cells. Within a few minutes after addition, 7β-hydroxycholesterol induced Ca2+ oscillations with a frequency of ~0.3-0.4 min-1. A few hours later, thapsigargin-sensitive Ca2+ pools were depleted, indicating that 7β-hydroxycholesterol perturbs intracellular Ca2+ homeostasis. The mitogen-activated protein kinases (MAPKs) ERK1 and ERK2 (but not JNK) were activated within 5 min after addition of 7β-hydroxycholesterol. The side-chain hydroxylated oxysterols 25-hydroxycholesterol and 27-hydroxycholesterol were more potent in inducing apoptosis than 7β-hydroxycholesterol and cholesterol-5α,6α-epoxide, as determined by TUNEL staining. Addition of TNFα (10 ng/ml) and IFNγ (20 ng/ml) enhanced the cytotoxicity of oxysterols and potentiated apoptosis. The cytokines alone were not toxic to smooth muscle cells at these concentrations. 25-Hydroxycholesterol and 7β-hydroxycholesterol but not cholesterol inhibited protein synthesis at 4-8 h as determined by [35S]methionine incorporation assay. Morphologically, oxysterol-induced cell death was characterized by disorganization of the ER and Golgi membranes. The Ca2+ and ERK signals preceded the ultrastructural changes induced by 7β-hydroxycholesterol. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)23-35
Number of pages13
JournalAtherosclerosis
Volume153
Issue number1
DOIs
StatePublished - Oct 30 2000

Keywords

  • 7β-Hydroxycholesterol
  • Ca oscillations
  • MAP kinase activation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of '7β-Hydroxycholesterol induces Ca<sup>2+</sup> oscillations, MAP kinase activation and apoptosis in human aortic smooth muscle cells'. Together they form a unique fingerprint.

Cite this