The impact of the MicroRNA-17-3p on the vascular effect of human immunodeficiency virus protein

Abstract

There are growing evidence for an association between human immunodeficiency virus (HIV)-infection and cardiovascular diseases, the pathogenesis of which involves vascular inflammation and endothelial dysfunction. HIV is a RNA-encoded retroviruses encircled with various viral proteins, including glycoprotein Gp-120 and regulatory protein Tat. Both Gp-120 and Tat have been shown to induce inflammatory responses in endothelial cells. One of the regulators of inflammatory responses is microribonucleic acid (microRNA), which is small noncoding RNA with gene silencing function at the post-transcriptional level. In view of the finding that microRNA-17-3p plays a role in modulating endothelial inflammation, the present work aimed to examine whether or not microRNA-17-3p modulated the detrimental effects of HIV-proteins, Gp-120 and Tat, on endothelial function.

Experiments were performed in cultured human aortic endothelial cells (HAECs) and in male C57BL/6J mice of 8 to 12 weeks old. HAECs were transfected with microRNA-17-3p agomir or its negative control (16 ng/ml), and incubated with Gp-120 (40 ng/ml) or Tat (100 ng/ml) for 16 hours. Mice were injected, via tail vein, with microRNA-17-3p agomir or its negative control (1 nmol), and intraperitoneally with HIV-proteins [Gp-120 (40 mg/kg) or Tat (100 mg/kg)] or the vehicle (phosphate-buffered saline), once daily for three days; after the treatment, mice were euthanized and lungs and aortae were isolated. The expression of microRNA-17-3p in HAECs and mouse aortae was measured with quantitative reverse transcription-polymerase chain reaction, and the levels of inflammatory mediators, tumor necrosis factor-alpha (TNF-α), intracellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1), in HAECs and mouse lungs, and the level of endothelial nitric oxide synthase (eNOS; the enzyme producing the major endothelium-derived relaxing factor nitric oxide) in mouse aortae were measured with Western immunoblotting. Vasoactive responses were studied by measuring the isometric tension of isolated aortae with Halpern-Mulvany myographs.

In HAECs, both Gp-120 and Tat increased the levels of TNF-α and ICAM-1, and the increases were suppressed by microRNA-17-3p overexpression. In mice treated with Gp-120 or Tat, the levels of TNF-α, ICAM-1 and MCP-1 in lungs were elevated; the elevation was not observed in mice receiving microRNA-17-3p agomir, which was associated with an increase in microRNA-17-3p level in the aorta.

The level of eNOS in aortae of mice treated with HIV-proteins was significantly decreased compared to those treated with the vehicle or with the HIV-proteins plus microRNA-17-3p agomir. HIV-proteins-treated mice showed a decrease in endothelium-dependent relaxations to acetylcholine, but not in endothelium-independent relaxations to DETA-NONOate; and the endothelium-dependent relaxation was restored by microRNA-17-3p-treatment. Treatment with HIV-proteins also resulted in greater contractions, in the presence of nitric oxide synthase inhibitor in aortae with endothelium, to acetylcholine while contractions to endothelium-independent vasoconstrictor U46619 were not affected. The enhancement of acetylcholine-induced contractions was prevented by concomitant treatment with microRNA-17-3p agomir.

In summary, microRNA-17-3p prevented the HIV-proteins-induced inflammatory responses and impairment of vascular tone regulation by endothelium. Therefore, induced expression of microRNA-17-3p may be a potential approach for preventing the development of cardiovascular diseases in HIV-infected patients.

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