Fig. 5.

The effect of oxidative stress in PON2-deficient MPM on DGAT1 activity. A: MPM lipid peroxide content was measured in the cell (3 × 10⁶) lipid extract of 2-, 3.5-, 5-, and 9-month-old PON2-deficient and control (C57BL/6) mice as described in Materials and Methods. B: MPMs from PON2-deficient mice at the age of 5 months were transfected with pcDNA3.1+ empty plasmid or with pcDNA3.1+ plasmid containing hPON2 for 4 h at 37°C. The cellular lipid peroxides content was determined 48 h after transfection. C: The microsomes from 5-month-old PON2-deficient mice (30 μg protein) were incubated at 37°C for 3 h with increasing concentrations (0–12 μg) of recombinant hPON2, followed by lipid extraction and lipid peroxide determination. D–F: MPMs from PON2-deficient mice at the age of 2 months were incubated overnight with no addition or in the presence of 2.5 mM of the free radical generator AAPH. D: Cells were then washed and the cellular lipid peroxide content was measured in the cells' lipid extract. E: The microsomal fraction was separated from untreated PON2-deficient MPM and from AAPH-treated cells. Microsomal DGAT1 activity was determined as described in Materials and Methods. F: Cellular triglyceride content was measured in the cells' lipid extract. Results are given as mean ± SD of three different experiments. *P < 0.01 versus control MPM; #P < 0.01 versus PON2-deficient MPM transfected with empty plasmid; ^∧P < 0.01 versus 0 concentration, **P < 0.01 versus PON2-deficient MPM.