NOX4 and Alzheimer disease: 2010). In a study by Umemoto et al. (2013), pre-exposure of cells to HDL inhibited the translocation of NOX-4 to lipid deposits in the plasma membrane and decreased ROS generation. None of the treatments in our study induced any changes in NOX-4 mRNA or HDL-cholesterol. However, in the AD group, NOX-4 gene expression was positively associated with HDL-cholesterol.