Effect of 7β-hydroxycholesterol on cellular redox status and heat shock protein 70 expression in macrophages

The proatherogenic effects of oxidized low-density lipoproteins are attributed to oxysterols, particularly 7 beta -hydroxycholesterol. In the present study, we have examined the effect of 7 beta -hydroxycholesterol on cellular redox status and heat shock protein70 (hsp70) expression. Murine peritoneal macrophages were incubated for 24 hours with increasing concentrations of 7 beta -hydroxycholesterol (0-25 mug/ml). Intracellular reduced glutathione levels decreased and oxidized glutathione levels increased, thus increasing the redox ratio. Hsp70 expression in macrophages decreased in a dose-dependent fashion. It is suggested that 7 beta -hydroxycholesterol exerts oxidative stress on macrophages and makes them more susceptible to its proatherogenic effects by impairing the cellular defense system consisting of antioxidants and stress proteins. Copyright (C) 2001 S. Karger AG, Basel.