475-P: Intermittent Hypoxia Increased the Expression of Intercellular Adhesion Molecule-1 and Endothelial Cell–Specific Molecule-1 in Vascular Endothelial Cells via the Downregulation of MicroRNA-181a1

Abstract

Sleep apnea syndrome (SAS), which is characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]), is a risk factor for vascular dysfunction, as well as hypertension, and insulin resistance/Type 2 diabetes. We have reported correlations between IH and insulin resistance/Type 2 diabetes, and hypertension. However, the question of why vascular dysfunction is induced by IH has remained unanswered. Here, we investigated the effects of IH on the expression of endothelial inflammatory transcripts such as intercellular adhesion molecule-1 (ICAM-1), interleukin (IL)-8, C-C motif chemokine ligand 5 (CCL5), endothelial nitric oxide synthase (NOS3), vascular cell adhesion molecule-1 (VCAM-1), endothelial cell specific molecule 1 (ESM1), and endothelin-1 (EDN-1) using an in vitro IH system. Human and mouse vascular endothelial cells (HUEhT-1 and UV2) were exposed to IH or normoxia for 24 hours. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of ICAM-1 and ESM1 in both HUEhT-1 (P=0.0436 and P=0.0145, respectively) and UV2 cells (P<0.0001 and P=0.0422, respectively). ELISA showed that ICAM-1 and ESM1 were significantly increased (P=0.0105 and P<0.0001, respectively) in the UV2 cell medium by IH. Reporter assays revealed that the promoter activities of ICAM-1 and ESM1 were not increased by IH. The microRNA (miR)-181a1 level of IH-treated cells was significantly decreased relative to that of normoxia-treated cells (P=0.0374). The IH-induced upregulation of ICAM-1 and ESM1 was abolished by the introduction of miR-181a1 mimic, indicating that IH stress increased levels of ICAM-1 and ESM1 via the inhibition of miR-181a1-mediated mRNA degradation, leading SAS patients to develop atherosclerosis. Disclosure S.Takasawa: None. M.Makino: None. A.Yamauchi: None. S.Sakuramoto-tsuchida: None. Y.Takeda: None. T.Uchiyama: None. R.Shobatake: None.