Objective: To examine the effects of HDAC inhibitor trichostatin A (TSA) on lipopolysaccharide (LPS) induced genes expression in cultured endothelial cells in order to understand the mechanisms involved in the protection of endothelial cells against vascular endothelium injury during endotoxemia.
Methods: Cultured EAhy926 cells (a cell line with the features of vascular endothelial cells) were treated with LPS at 100 ng/ml [the dose was chosen for minimum impact on cell survival as determined using Methyl thiazolyl tetrazolium (MTT) assay], or LPS and TSA (100 μg/ml). The expressions of toll-like receptor 4 (TLR4) and HDAC2 were measured by Western blotting 3, 6, 9, 12 and 24 hours after the beginning of the treatment.
Results: The expressions of TLR4 (as measured by densitometry) was found significantly higher (P< 0.01) in LPS treated cells (1.01±0.14, 1.25±0.16, 1.20±0.19) 9, 12 and 24 hours after the beginning of the treatment as compared to untreated cells (0.34±0.05); The expression of HDAC2 was also found significantly higher (P< 0.01) after LPS treatment for 12 and 24 hours (1.14±0.10, 1.20±0.04) in comparison with untreated control (0.17±0.02). In LPS+TSA treated cells, TLR4 expression (0.37±0.07) was significantly lower (P< 0.05) after 12 hours of treatment in comparison with its LPS treated counterpart (1.25±0.16), while the level of TLR4 expression stayed unchanged 24 hours after the beginning of the treatment, as compared to the result at 12 hours (0.37±0.10 vs. 1.20±0.19, P> 0.05). No visible HDAC2 expression was detected in the cells treated with LPS+TSA.
Conclusion: LPS stimulated the increase of TLR4 and HDAC2 expression in the vascular endothelial cells studied while TSA suppress the LPS induced TLR4 and HDAC2 expression in these cells.