Transcriptional coactivator p300 regulates glucose-induced gene expression in endothelial cells

Abstract

Sustained hyperglycemia in diabetes causes alteration of a large number of transcription factors and mRNA transcripts, leading to tissue damage. We investigated whether p300, a transcriptional coactivator with histone acetyl transferase activity, regulates glucose-induced activation of transcription factors and subsequent upregulation of vasoactive factors and extracellular matrix (ECM) proteins in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated in varied glucose concentrations and were studied after p300 small interfering RNA (siRNA) transfection, p300 overexpression, or incubation with the p300 inhibitor curcumin. Histone H2AX phosphorylation and lysine acetylation were examined for oxidative DNA damage and p300 activation. Screening for transcription factors was performed with the Luminex system. Alterations of selected transcription factors were validated. mRNA expression of p300, endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and fibronectin (FN) and its splice variant EDB(+)FN and FN protein production were analyzed. HUVECs in 25 mmol/l glucose showed increased p300 production accompanied by increased binding of p300 to ET-1 and FN promoters, augmented histone acetylation, H2AX phosphorylation, activation of multiple transcription factors, and increased mRNA expression of vasoactive factors and ECM proteins. p300 overexpression showed a glucose-like effect on the mRNA expression of ET-1, VEGF, and FN. Furthermore, siRNA-mediated p300 blockade or chemical inhibitor of p300 prevented such glucose-induced changes. Similar mRNA upregulation was also seen in the organ culture of vascular tissues, which was prevented by p300 siRNA transfection. Data from these studies suggest that glucose-induced p300 upregulation is an important upstream epigenetic mechanism regulating gene expression of vasoactive factors and ECM proteins in endothelial cells and is a potential therapeutic target for diabetic complications.

Transcriptional Alterations of ET-1 Axis and DNA Damage in Lung Tissue of a Rat Obesity Model

“…Our findings are in line with the observation that human umbilical vein endothelial cells grown at high-glucose concentrations exhibited a greater number of g-H2AX-positive nuclei than cells grown at normal glucose levels, this being the consequence of overproduction of the p300 transcriptional coactivator together with its increased binding to ET-1 (Chen et al, 2010). …”

miR-200b Mediates Endothelial-to-Mesenchymal Transition in Diabetic Cardiomyopathy

“…However, miR-200b also regulates p300 production (8). As shown in this and our previous reports, a large number of molecules that cause EndMT may further be regulated through p300-dependant histone acetylation (8,10,15,25). Further experiments are needed to decipher the specific contribution of each pathway.…”

Genetic and environmental factors associated with type 2 diabetes and diabetic vascular complications

“…Histone modifications (altered acetylation, methylation, phosphorylation, and/or sumoylation) control transcription expression, cell cycle regulation, and cellular differentiation [132,133]. In vitro studies in endothelial cell lines demonstrated that cells exposed to hyperglycemia underwent histone modification, activation of multiple transcription factors [134], increased H3K4 methylation at the NF-κB-p65 promoter, enhanced expression of NF-κB-p65, and increased NF-κB-driven pro-inflammatory gene expression [135].…”