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Diabetes research and clinical practice

High glucose and/or high insulin affects HIF-1 signaling by regulating AIP1 in human umbilical vein endothelial cells.


PMID 26021979

Abstract

The objective of this study was to explore the effects of high glucose/high insulin on AIP1 expression in HUVECs and the possible regulation of HIF-1α signaling by AIP1. We investigated the expression of AIP1 and HIF-1α signaling in HUVECs at the levels of mRNA and protein following exposure to 30 mmol/L glucose (high glucose), 1 nmol/L insulin (high insulin), and the combination of the two (high glucose/high insulin). We detected changes in HIF-1α and VEGF expression with AIP1 siRNA interference by real-time PCR and western blotting. The CCK8 cell proliferation assay, the scratch/wound-healing assay, and flow cytometry were used to assess cell proliferation, migration and apoptosis, respectively. Matrigel was used to perform a tubule formation assay. Compared with 5.5 mmol/L glucose alone (control), high glucose, high insulin, and the combination of high glucose+high insulin increased AIP1 expression at 24 h at the mRNA and protein levels. High glucose, high insulin, and high glucose+high insulin decreased HIF-1α expression at the mRNA and protein levels. AIP1 knockdown significantly increased HIF-1α and VEGF expression at both the mRNA and protein levels in HUVECs under high glucose conditions. In the presence of high insulin, the effect of high glucose on target gene expression was altered. The downregulation of AIP1 promoted cell proliferation, migration, and tubule formation, and it decreased apoptosis. High glucose increases AIP1 expression and decreases the expression of HIF-1α and downstream molecules. Decreased HIF-1α signaling may be regulated by increased AIP1 under high glucose.