Stability and time course of epigenetic changes by S-/N-alkylating substances: Stabilität und Zeitverlauf epigenetischer Veränderungen durch S-/N-alkylierende Substanzen

Wilhelm Bloch, Thilo Simons, Dirk Steinritz, Annette Schmidt, Birgit Bölck

Publication: Chapter in Book/Report/Conference proceedingConference contribution - Published abstract for conference with selection processResearchpeer-review

Abstract

Sulfur mustard (SM: 2,2´dichlorodiethyl sulfide) and nitrogen mustards (N-Lost) are alkylating agents that affect DNA and other molecules in the body. SM was widely used in military conflicts, the last being the Iran-Iraq war with more than 100.000 Iranians exposed, one third of whom are still suffering from late effects. Skin xerosis or ulceration, pigmentation disorders and scars are among the most long-term skin lesions after contact with SM. During the wound healing process endothelial stem and precursor cells (hEPC = human endothelial progenitor cells) play a central role. For S- and N-Lost only less is known about their long-term effects on precursor cells (EPC), stem cells and endothelial cells. The based epigenetic modifications could be responsible for observed long term tissue damage after S-Lost intoxication. Therefore the influence of sulfur mustard and the nitrogen mustard such as Chlorambucil on MACS, adult hEPC and HUVEC has been checked.
After the treatments with sulfur mustard / Chlorambucil for 24 hrs, the cells were cultured either in the time series (24, 48, 72, 96 hrs post treatment) or in long-term experiments over several cell passages. Subsequently, the cells were examined for changes in epigenetic markers such as the global methylation status (5'-methylcytosine (5-mC) and 5'-hydroxy-methylcytosine (5-hmC)) as well as for concentration-/ time-dependent changes in histone modifications were analyzed.
S- Lost and Chlorambucil lead to a very complex epigenetic damage, which can already be seen after 24 hrs. Following S-Lost or Chlorambucil treatment complex time-, passage- and concentration-dependent changes were detected in 5-mC as well as 5-hmC status. Often the observed effects on methylation status increased in addition during the time series or during the subsequent passaging. The findings show, that some epigenetic changes are sometimes very stable. Furthermore, differential and long-term histone modifications (such as histone deacetylation or methylation) are important means for the transcriptional repression of genes and were also detected.
All this finding suggests epigenetic long-term modulations of endothelial cells by alkylating agents. S- and N-Lost cause also growth and differentiation damage of endothelial and endothelial precursor cells which leads to a damage of vessel formation. Protection of these cells against S- and N-Lost induced damage could upgrade the vessel formation. For this reason, we have searched after specific epigenetic modulators to inhibit epigenetic damages on the endothelial cells. In the present study, we investigated the treatments with 5-Aza-2'-deoxycytidine (decitabine; DAC), an inhibitor of DNA methyltransferase, as well as the anesthetic procaine on methylation status of the Chlorambucil-damaged MACS cells. In these time series we observed, that the treatment with DAC (5 µM) or also with procaine (5 mM) for 24 hrs. led to demethylations.
The observation clearly show, that besides structural DNA changing also epigenetic modifications could be the reason for long term tissue damage after S-Lost intoxication and explain why the tissue damage can still exist after years. Reverse, these epigenetic observations could consequently become a new therapeutic target.
Original languageGerman
Title of host publicationUmsetzung experimenteller Forschungsergebnisse zur Verbesserung der Therapie bei Vergiftung durch chemische Kampfstoffe
Number of pages1
Publication date22.04.2015
Publication statusPublished - 22.04.2015
EventMedical Chemical Defence Conference - München, Germany
Duration: 22.04.201523.04.2015
Conference number: 16

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