Mitochondrial cholesterol transporter, StAR, inhibits human THP-1 monocyte-derived macrophage apoptosis.

Steroidogenic acute regulatory protein (StAR) plays an important role in the maintenance of intracellular lipid homeostasis. Macrophages are the key cellular player in the pathophysiology of atherosclerosis. Imbalance of macrophage lipid homeostasis causes cellular apoptosis, which is the key process in the initiation of atherosclerosis. The present study has investigated the effects of StAR in the apoptotic process of human THP-1 derived macrophages induced by serum withdrawal or Ox-LDL. Overexpression of StAR significantly decreased the number of apoptotic macrophages by decreasing the expression of pro-apoptotic genes Caspase-3 and Bax mRNA and protein levels, as well as through increasing expression of anti-apoptotic gene Bcl-2 mRNA and protein levels in the absence and presence of Ox-LDL. The results indicate that StAR plays an important role in macrophage and foam cell apoptotic processing, which may provide a potential method for preventing atherosclerosis.