Increase in nuclear calcium in smooth muscle cells exposed to oxidized low density lipoprotein

Abstract

Vascular smooth muscle cells respond with an increase in intracellular Ca²⁺ within seconds after exposure to oxidized low density lipoprotein (oxLDL). This has been suggested to represent a signaling response that may have implications for gene expression. If so, oxLDL may induce increases in nuclear Ca²⁺ in smooth muscle cells in response to oxLDL. Aortic smooth muscle cells were exposed to 100 μg/ml oxLDL. Large, rapid increases in [Ca²⁺]_i were observed using fluo-3 as an indicator dye to detect intracellular Ca²⁺ on the stage of a confocal micro-scope. This was also confirmed using ratiometric imaging of indo signals. These elevations appeared to be localized to the nuclear region of the cell. DNA staining of the cells confirmed its localization to the nuclear / perinuclear region of the cell. Our data demonstrate that oxLDL induces a nuclear localized elevation in Ca²⁺i that may have important implications for nuclear function.

Keywords:

• nucleus
• atherosclerosis
• inositol trisphosphate
• gene expression
• free radicals