Chromatin Immunoprecipitation Assay in Liver Tissue

In short, ChIP was performed as described previously [66 (link)] with minor modifications. Frozen livers (approximately 50 mg per IP) were homogenized in 1% Formaldehyde PBS solution using Ultra-Turrax homogenizer on level 5 for 10 seconds, with following cross-linking at room temperature for 10 minutes. The suspension was quenched by adding 0.125 M glycine and incubating additional 10 minutes at room temperature. Cross-linked cells were washed in PBS, resuspended in lysis buffer (0.1% SDS, 1% Triton X-100, 0.15 M NaCl, 1 mM EDTA, 20 mM TrisHCl [pH 8.0], and BSA 1 mg/ml), and sonicated using Bioruptor (Diagenode) or ME220 Focused-ultrasonicator (Covaris). Chromatin was immunoprecipitated over night at 4 °C using antibodies and Protein A/G agarose beads (Santa Cruz, sc-2003). H3K27Ac ChIP was done with 0.2 μl/IP of H3K27Ac antibody Ab4729 (Abcam). GR ChIP antibody cocktail consisted of 1 μg/IP of MA1-510 (Thermo Fisher), 1 μg/IP of PA1-511a (Thermo Fisher), and 1μg/IP of sc-1004 (Santa Cruz). FOXO1 ChIP was done with 3 μg/IP of sc-11350 (Santa Cruz). Immunocomplexes were washed, and chromatin was eluted (1% SDS with 0.1 M NaHCO₃) and decross-linked over night at 65 °C. DNA was phenol/chloroform purified and ethanol precipitated. Recovery was analyzed by qPCR using primers listed in S2 Table and/or sequenced.