Host Defense against Viral Infection Involves Interferon Mediated Down-Regulation of Sterol Biosynthesis (original) (raw)
Figure 2
Effect of a coordinated reduction in multiple enzymes on sterol biosynthesis.
(A) Comparison by Western blot analysis of HMGCS1, HMGCR, and SQLE protein levels in mCMV infected (24 hpi) or mock-treated BMDM. Infection was measured by detection of the IE1 mCMV antigen. Intensity values relative to β-actin calculated by densitometry show a decrease of the total amount of protein in the mCMV-infected BMDM compared to the mock-treated samples of 64% for HMGCS1, 50% for HMGCR, and 85% for SQLE. Graphs are representative of two independent experiments with biological duplicates and triplicates, respectively. (B–C) Free cholesterol concentration was determined experimentally by enzymatic assay (Materials and Methods) at 0, 6, 24, 48, and 72 hpi in BMDM (B) and NIH/3T3 cells (C). Cholesterol content is presented as the percentage of free intracellular cholesterol concentration from infected cells compared to mock treatment. Graphs represent the means ± SD of three independent experiments with biological quadruplicates for each experiment. (D) Free cholesterol concentration in BMDM cultures treated with varying concentrations of IFNγ, IFNβ, TNF, IL1β, or IL6. The cholesterol concentration was measured as mentioned above after 48 h post-cytokine treatment. Bars represent means ± SD of two independent experiments with biological quadruplicates for each experiment. *p<0.05, **p<0.01, ***p<0.001, determined with an unpaired Student's t test.