High Glucose Induces Endothelial COX2 and iNOS Expression via Inhibition of Monomethyltransferase SETD8 Expression

Jie Qi,Qian Cheng,Minmin Zhu,Qichao Wu,Xiangyuan Chen,Changhong Miao

doi:10.1155/2020/2308520

Jie Qi, Qian Cheng + Show 4 more

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https://doi.org/10.1155/2020/2308520

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Abstract

Cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS) overexpression results in endothelial apoptosis, thus mediating vascular endothelial injury in hyperglycaemia. E26 transformation-specific sequence transcription factor-1 (ESE-1), which belongs to the E26 transformation-specific family of transcription factors, has been demonstrated to be involved in COX2 and iNOS gene transcription. Our previous study indicated that SET domain-containing protein 8 (SETD8) downregulation is involved in high glucose-mediated endothelial inflammation in human umbilical vein endothelial cells (HUVECs). Here, we report that SETD8 plays a major role in hyperglycaemia-induced COX2 and iNOS expression. In HUVECs, upregulation of ESE-1 expression was related to high glucose-mediated apoptosis and COX2 and iNOS expression. High glucose inhibited SETD8 expression, and overexpression of SETD8 diminished the effects of high glucose treatment. Consistently, RNA silencing of SETD8 led to the opposite effect. Furthermore, SETD8 was found to interact with specificity protein 1 (SP1). Blockade of SP1 protected against high glucose-mediated endothelial injury. Mechanistically, we showed that H4K20me1, a downstream target of SETD8, and SP1 were enriched at the ESE-1 promoter region by ChIP assay. Luciferase reporter assays indicated that SETD8 overexpression attenuated ESE-1 promoter activity and augmented the inhibitory effect of siSP1 on ESE-1 promoter activity. In general, our data indicate that SETD8 interacts with SP1 to coregulate ESE-1 expression, which is involved in hyperglycaemia-mediated endothelial apoptosis in HUVECs.

Highlights

The prevalence of diabetes has been increasing dramatically for decades, resulting in a growing public health problem worldwide [1]
To determine whether high glucose could mediate endothelial apoptosis in human umbilical vein endothelial cells (HUVECs), cells were subincubated in different types of media: normal glucose (Con, 5 mM, 3 days), osmotic control, and high glucose (HG, 25 mM, 3 days)
The results indicated that high glucose induced cell apoptosis (Figure 1(a)) and increased the expression of cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS) at the protein (Figures 1(b) and 1(c)) and mRNA (Figure 1(d)) levels in HUVECs

Summary

Introduction

The prevalence of diabetes has been increasing dramatically for decades, resulting in a growing public health problem worldwide [1]. Accumulating evidence suggests that endothelial apoptosis is involved in the pathogenesis of cardiovascular complications in diabetic patients [4,5,6]. Proinflammatory enzymes, including cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS), have been reported to participate in hyperglycaemiamediated endothelial apoptosis and the occurrence of diabetes-related complications [7, 8]. ESE-1 expression is increased upon inflammatory stimuli in vascular endothelial cells [10]. ESE-1 has been reported to be involved in the activation of COX2 [11] and iNOS [10] gene expression by modulating transcription, participating in endothelial apoptosis. As an inducer of COX2 and iNOS gene expression [10, 11], ESE-1 may become a potential target for hyperglycaemiamediated endothelial apoptosis and injury

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