Early life stress induces endothelial‐derived HDAC9 and ET‐1 expression

Abstract

Exposure to adverse childhood experiences, also known as early life stress (ELS), is an independent risk factor for the development of cardiovascular disease (CVD) in adulthood. Endothelial dysfunction is a major contributor to the development of CVD and has been linked to childhood adversity induced CVD risk. We previously reported circulating ET‐1 levels are significantly elevated in young adults exposed to childhood adversity in humans. Endothelin‐1 (ET‐1) via the ETA receptor promotes endothelial dysfunction and vascular inflammation. However, the regulation of ET‐1 by ELS and the mechanistic link between elevated ET‐1 levels and ELS‐induced increase in CVD risk remains unknown. In a mouse model of ELS involving maternal separation and early weaning (MSEW), we previously reported that ELS induced elevated plasma ET‐1 as well as increased vascular histone deacetylase 9 (HDAC9) protein expression with no changes in expression of other HDAC isoforms. Moreover, MSEW mice develop endothelial dysfunction in adulthood that is attenuated by a pan‐inhibitor of Class I and class II HDAC proteins, trichostatin A (TSA). HDACs are a family of epigenetic enzymes that regulate transcription through deacetylation of histone and non‐histone proteins. In humans, previous studies have shown SNPs in the HDAC9 gene are prominent in large artery stroke and coronary artery disease and that upregulated HDAC9 expression is localized in endothelial cells of carotid atherosclerotic human tissue suggesting HDAC9 may play an important role in atherogenesis. Therefore, we hypothesized that vascular HDAC9 upregulation promotes endothelial dysfunction in MSEW mice via increased ET‐1. MSEW involves maternal separation 4 h/day (postnatal (PD) 2 to 5) and 8 h/day (PD6 to 16) and weaned at PD17. Normally reared litters weaned at PD21 were used as controls (CON). In adult male CON and MSEW mice, we determined aortic localization of HDAC9 and ET‐1. Immunohistolocalization showed aortic HDAC9 is upregulated specifically in the endothelial cells of MSEW mice (n=5/group). Confocal immunofluorescence imaging revealed aortic ET‐1 expression is also localized in the endothelium of both CON and MSEW mice. To examine the effects of endothelial HDAC9 on ET‐1 expression, we used mouse aortic endothelial cells (MAECs) transfected with control vector or HDAC9 plasmid incubated in the presence or absence of TSA. Cultured MAECs treated with TSA blunted ET‐1 expression (70% decrease from vehicle, p<0.05, n=3/group). Furthermore, HDAC9 over‐expression in cultured MAECs significantly increased ET‐1 expression (relative to control vector group, 1.0±0.08 vs 1.73±0.44 arbitrary units, p<0.05, n=3/group) and TSA reduced the HDAC9‐dependent ET‐1 expression (1.68 fold decrease from control vector vehicle group, p<0.05, n=3/group). Our findings indicate endothelial dysfunction previously observed in our MSEW mouse model may be mediated by HDAC9‐dependent elevated ET‐1 production. In conclusion, this study highlights the importance of ELS in the development of CVD and the implications of an epigenetic pathway as a potential mechanistic link.Support or Funding InformationNIH P01 HLP0169999; NIH K01 DK105038This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.