Aims: Cells undergo apoptosis in stressed status such as in intracellular calcium overload or extracellular calcium/magnesium deficiency. The mechanisms of how deficiency of the divalent metal ions induces apoptosis remain to be defined. Scavenger receptor BI (SR-BI) is a high density lipoprotein (HDL) receptor. Recent studies demonstrated that SR-BI is a stress response molecule which induces apoptosis upon serum deprivation. In this study, we assessed our hypothesis that the deficiency of calcium/magnesium induces apoptosis via SR-BI apoptotic pathway. Main methods: We employed CHO cell lines expressing vector and SR-BI to test the effect of SR-BI on apoptosis induced by deficiency of calcium, magnesium and zinc in culture medium. The regain of different metal ions in deficient medium was also performed, respectively. Cell death was detected by morphological changes and quantified by LDH cytotoxicity assay. Apoptosis was also assessed by DNA ladder assay and DNA condensation assay. The SR-BIC323G mutant cells which lack the apoptotic activity of SR-BI were employed to verify the SR-BI-dependent effect on calcium/magnesium induced apoptosis. Key findings: The deficiency of calcium/magnesium induced cell apoptosis in CHO-SR-BI cells, but not in CHO-vector cells. Moreover, no apoptotic cell death was observed in SR-BIC323G mutant cells, indicating that the deficiency of divalent metal ions induces apoptosis in a SR-BI-dependent manner. Furthermore, the restoration of calcium or magnesium, but not zinc, protected CHO-SR-BI cells from apoptotic cell death, in a dose-dependent fashion. Significance: These findings extend our understanding about how calcium and magnesium deficiency induces apoptosis.
|Number of pages
|Published - Mar 28 2011
Bibliographical noteFunding Information:
We thank the members of the Kentucky Pediatric Research Institute for invaluable advice and assistance. This work was supported by grants to XAL from American Heart Association (0530241 N), NIH (R01GM085231 and 3R01GM085231-02 S1) and Children's Miracle Network.
- Scavenger receptor BI
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology (all)
- Pharmacology, Toxicology and Pharmaceutics (all)