Lacking cytokine production in ES cells and ES-cell-derived vascular cells stimulated by TNF-α is rescued by HDAC inhibitor trichostatin A

Abstract

Inflammation and TNF-α signaling play a central role in most of the pathological conditions where cell transplantation could be applied. As shown by initial experiments, embryonic stem (ES) cells and ES-cell derived vascular cells express very low levels of TNF-α receptor I (TNFRp55) and thus do not induce cytokine expression in response to TNF-α stimulation. Transient transfection analysis of wild-type or deletion variants of the TNFRp55 gene promoter showed a strong activity for a 250-bp fragment in the upstream region of the gene. This activity was abolished by mutations targeting the Sp1/Sp3 or AP1 binding sites. Moreover, treatment with trichostatin A (TSA) led to a pronounced increase in TNFRp55 mRNA and promoter activity. Overexpression of Sp1 or c- fos further enhanced the TSA-induced luciferase activity, and this response was attenuated by Sp3 or c- jun coexpression. Additional experiments revealed that TSA did not affect the Sp1/Sp3 ratio but caused transcriptional activation of the c- fos gene. Thus, we provide the first evidence that ES and ES-cell-derived vascular cells lack cytokine expression in response to TNF-α stimulation due to low levels of c- fos and transcriptional activation of Sp1 that can be regulated by inhibition of histone deacetylase activity.