title: 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.
authors.affiliation: Department of Pathology, University of Western Ontario, Schulich School of Medicine, London, Ontario, Canada.
authors.forename: Shali
authors.initials: S
authors.lastname: Chen
authors.forename: Biao
authors.initials: B
authors.lastname: Feng
authors.forename: Biju
authors.initials: B
authors.lastname: George
authors.forename: Rana
authors.initials: R
authors.lastname: Chakrabarti
authors.forename: Megan
authors.initials: M
authors.lastname: Chen
authors.forename: Subrata
authors.initials: S
authors.lastname: Chakrabarti
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000818:Animals; D001011:Aorta / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D004249:DNA Damage / Q000502:physiology; D048909:Diabetes Complications / Q000235:genetics* / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D019332:Endothelin-1 / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000494:pharmacology*; D006657:Histones / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D051381:Rats; D017207:Rats, Sprague-Dawley; D014471:Umbilical Veins / Q000166:cytology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D016326:Extracellular Matrix Proteins; D006657:Histones; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D050880:p300-CBP Transcription Factors; D005947:Glucose