Lipopolysaccharides (LPS) induce tumor necrosis factor-a (TNF-a) production in cardiomyocytes, which contributes to myocardial depression during sepsis. However, the underlying mechanisms remain not fully understood. This study was undertaken to investigate the contribution of histone deacetylase (HDAC) to TNF-a expression in cardiomyocytes and the signaling mechanism of LPS-induced HDAC activation. Here, we show for the first time that LPS increases HDAC activity and that inhibition of HDAC decreases LPS-stimulated TNF-a expression via the accumulation of NF-¿B/p65 at the TNF-a promoter in cardiomyocytes. Using a positive screen, we have further identified HDAC3 as a specific member of the HDAC family able to regulate TNF-a production. Furthermore, our data reveal that LPS-induced HDAC activity is mediated through reactive oxygen species from mitochondria and c-Src signaling. In summary, this study demonstrates a novel signaling mechanism by which LPS via mitochondrial reactive oxygen species/c-Src/HDAC3 pathways mediate TNF-a expression in cardiomyocytes.

Read more »