Effect of 7beta-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 7beta-hydroxycholesterol. In the present study, we have examined the effect of 7beta-hydroxycholesterol on cellular redox status and heat shock protein 70 (hsp70) expression. Murine peritoneal macrophages were incubated for 24 hours with increasing concentrations of 7beta-hydroxycholesterol (0-25 microg/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 7beta-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.