Conclusions Our data demonstrate an important role of histone modifications, including histone H3 acetylation and H3K4, H3K9 and H3K27 methylation state, in LPS-mediated IL-8 gene activation in intestinal epithelial cells. In particular we demonstrate that H3-acetyl, H3K4me2 and H3K9me2 changes are early, transient and correlate with the modulation of IL-8 transcriptional activity. Conversely, increase of H3K27me3 levels at IL-8 gene occurs later and is long lasting. Our data
provide novel insights into the epigenetic mechanisms that control transcription and gene expression in LPS response. Methods Cell culture Selleck ALK inhibitor The human colon cell lines HT-29 were grown in Dulbecco’s Modified Eagle’s Medium supplemented with 10% fetal bovine serum (Life Technologies), 2 mM glutamine, penicillin (25 U/mL) and streptomycin (25 μg/mL) in a 5% CO2 atmosphere at 37°C. Cells were pretreated with Human interferon-γ (INF-γ) (Roche Applied Science, Germany) 10 ng/ml for 12 hours or control medium, washed, and then stimulated with LPS 50 ng/ml. LPS (Escherichia coli, O55:B5) were purchased from Sigma-Aldrich GW-572016 order (St. Louis, MO) and reconstituted in endotoxin-free water. 5-aza-2-deoxyazacytidine (ICN Biomedical Inc.) treatments were performed
at 5 μM and 50 μM final concentration while trichostatin (TSA) (Sigma Aldrich) was used at 25 and 100 nM. Western Blot Analysis Cell extracts were prepared in Nonidet P40 lysis buffer with 1 mM PMSF and Complete™ protease inhibitors mix (Roche, Indianapolis, IN, USA). 50 μg of proteins were resolved by electrophoresis using 10% SDS-PAGE gels and transferred to BA 85 0.45 μm PROTAN nitrocellulose filters (Schleicher & Schnell, Inc., Dassel, Germany). The blots were incubated with rabbit anti-IκB-α
antibodies (Santa Cruz Biotechnology, Santa Cruz, CA, USA) and mouse anti-γ-tubulin antibodies (Sigma-Aldrich Corp. St. Louis, MO, USA) as a control for protein loading. Immunoblots were stained with correspondent secondary antibodies IgG (Amersham Pharmacia Biotech, Buckinghamshire, UK), and revealed Clomifene with the enhanced chemiluminescence detection system IgG (ECL, Amersham Pharmacia Biotech, Buckinghamshire, UK). Western blot analyses of each sample were performed more than three times. Protein levels were quantified using the software Quantity One (Bio-Rad). Quantitative and semiquantitative RT-PCR analysis Total RNA was isolated with RNeasy extraction kit see more QIAGEN (Qiagen,GmBh) according to the manufacturer instructions. The integrity of the RNA was assessed by denaturing agarose gel electrophoresis (presence of sharp 28S, 18S and 5S bands) and spectrophotometry.