High glucose-induced increased expression of endothelin-1 in human endothelial cells is mediated by activated CCAAT/enhancer-binding proteins

Abstract

High glucose-induced endothelial dysfunction is partially mediated by the down-stream pathophysiological effects triggered by increased expression of endothelin-1 (ET-1). The molecular control mechanisms of ET-1 synthesis are yet to be discovered. Members of the CCAAT/enhancer-binding proteins (C/EBP) family are important regulators of key metabolic processes, cellular differentiation and proinflammatory genes. In this study, we aimed at elucidating the role of C/EBP in mediating the high glucose effect on ET-1 expression in human endothelial cells (EC). Human umbilical vein cells (EAhy926) and primary cultures of human aortic EC were exposed to high levels of glucose (16.5-25 mM). Real-time PCR, Western blot, enzyme-linked immunosorbent assay, ET-1 promoter-luciferase reporter analysis, and chromatin immunoprecipitation assays were employed to investigate ET-1 regulation. High glucose activated C/EBPa, C/EBPb, and C/EBPd in a dosedependent manner. It also promoted significant increases in ET-1 gene and peptide expression. Chemical inhibition of JNK, p38MAPK and ERK1/2 diminished significantly the high glucose-induced nuclear translocation of C/EBP and ET-1 expression. Silencing of C/EBPa, C/EBPb or C/EBPd greatly reduced the high glucose-induced upregulation of ET-1 mRNA, pre-pro-ET-1, and ET-1 secretion. The expression of various C/EBP isoforms was selectively downregulated by siRNA-mediated gene silencing. In silico analysis indicated the existence of typical C/EBP elements within human ET-1 gene promoter. Transient overexpression of C/EBPa, C/EBPb or C/EBPd upregulated the luciferase level controlled by the ET-1 gene promoter. The direct interaction of C/EBPa, C/EBPb or C/EBPd proteins with the ET-1 promoter in high glucose-exposed EC was confirmed by chromatin immunoprecipitation assay. High glucose-induced ET-1 expression is mediated through multiple mechanisms. We present evidence that members of the C/EBP proinflammatory transcription factors are important regulators of ET-1 in high glucose-exposed human endothelial cells. High glucose-induced activation of C/EBP-related signaling pathways may induce excessive ET-1 synthesis, thus promoting vasoconstriction and dysfunction of the vascular wall cells in diabetes.

Endothelin-1 traps potently reduce pathologic markers back to basal levels in an in vitro model of diabetes

“…As previously discussed, ET-1 levels are pathologically elevated in diabetes [10,11]. Research indicates that high glucose (the primary feature of diabetes) can induce ET-1 levels [22]. Hence, it is fitting that our ET-trap construct also has a positive effect on returning ECM protein levels back to basal levels after high glucose treatment ( Figs.…”

Interleukin‐34 mediated by hepatitis B virus X protein via CCAAT/enhancer‐binding protein α contributes to the proliferation and migration of hepatoma cells

“…Previous researches show that multiple signal pathways, including PI3-K, NF-κB, JNK and p38, contribute to the expression of CEBP/α in different cells. [23][24][25] Furthermore, HBX could induce the activation of these pathways to regulate the expression of various cellular factors in HCC cells. 17,41,42 In addition, JNK and NF-κB pathways have been reported to induce the expression of IL-34 in cells with multiple types.…”

“…Current reports showed that CEBP/α expression is mainly mediated by PI3-K, 23 NF-κB, 24 JNK and p38 pathways in different cells. 25 We examined whether HBX was able to promote CEBP/α expression through these pathways. The results showed that HBX could activate PI3-K, NF-κB, JNK and p38 pathways in HCC cells ( Figure 3).…”

Blockade of endothelin B receptor improves the efficacy of levetiracetam in chronic epileptic rats

“…In addition, ET-1 regulates PGP expression and transport activity in isolated, intact rat brain capillaries, but not in rat brain capillary endothelial cell lines [11][12][13][14][15]. In addition, ET-1 activates the p38 mitogen-activated protein kinase (p38MAPK) signaling pathway, which is involved in the regulation of PGP and ET-1 expression [16][17][18][19][20][21][22]. Interestingly, ET B receptor activation potentiates the production and secretion of more ET-1 in an autocrine positive feedback loop [23][24][25][26].…”