Comparative analyses of genome methylation in monocytes trained by cholesterol and LPS

We performed comparative studies of monocytes trained by either PBS, cholesterol or varying dosages of LPS, in order to examine the differential innate responses to stress signals. Differentially trained monocytes were subjected to whole genome methylation array analyses. Our data reveal that monocytes trained by either cholesterol or very low dose LPS preferentially clustered together in terms of their genome methylation profiles, separate from the naïve PBS treated monocytes or monocytes trained by high dose LPS. Our findings suggest that monocytes may similarly respond to the generic membrane stress signals caused by either very low dose LPS or cholesterol, in contrast to the exhausted state induced by high dose LPS. Genome-wide DNA methylation profiling was performed using Infinium Mouse Methylation BeadChip arrays. Based on variability observed in previous studies, a minimum of 4 biological replicates was determined to be sufficient for most BMMC culture experiments, which is sufficiently powered to detect differences in 5mC as low as 5%. All experiments were performed on at least two separate days and with mice from at least 3 separate litters.