N-Hydroxy-7-(2-naphthylthio) Heptanomide Inhibits Retinal and Choroidal Angiogenesis

Abstract

Histone deacetylase (HDAC) is a key enzyme regulating gene expression, including angiogenic cytokine expression. We have previously identified a novel synthetic HDAC inhibitor, known as N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA), with antitumor properties. Here, we investigated the antiangiogenic properties of this small synthetic molecule both in vitro and in vivo. HNHA inhibited nuclear HDAC enzyme activity in human umbilical endothelial cells (HUVECs), an effect accompanied by histone hyperacetylation, p21 upregulation, and cell cycle arrest. HNHA also inhibited vascular endothelial growth factor-induced tube formation and migration of HUVECs, in the absence of any detectable cellular toxicity. Intravitreous injection of HNHA into mice inhibited retinal neovascularization associated with oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV), as determined through fluorescence angiography and vessel counting. Retinas from HNHA-treated animals had a normal histological appearance without any detectable increase in terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells, showing that this compound did not induce retinal toxicity. These findings indicate that HNHA has direct antiangiogenic effects and may be an effective strategy for inhibiting the pathological retinal and choroidal neovascularization underlying blinding eye diseases.

The inhibition of retinal neovascularization by gold nanoparticles via suppression of VEGFR-2 activation

“…OIR was induced as described by Smith et al [7], with some modifications [20-22]. Briefly, newborn mice were randomly assigned to experimental and control groups.…”

“…As we noted in our previous description [20-22], at P17, deeply anesthetized mice were perfused through the tail vein with fluorescein-conjugated dextran (molecular weight 500,000; Sigma) dissolved in phosphate-buffered saline (PBS; 137mM NaCl, 10mM phosphate, 2.7mM KCl, pH 7.4). After 1 h of perfusion, the eyes were enucleated and fixed in 4% paraformaldehyde for 2 h. The retinas were dissected, flat-mounted in Dako mounting medium (DakoCytomation, Glostrup, Denmark), and viewed by fluorescence microscopy (BX50; Olympus, Tokyo, Japan) at a magnification of 4×.…”

“…As we noted in our previous description [20-22], at P17, the eyes were removed, fixed in 4% paraformaldehyde for 24 h, and embedded in paraffin. Sagittal sections of 5 µm, each 30 µm apart, were cut through the cornea parallel to the optic nerve.…”

How to overcome retinal neuropathy: The fight against angiogenesisrelated blindness

“…That is, VEGF is involved in both angiogenesis and breakdown of the blood-retinal barrier. We repeatedly observed VEGF-induced increases in tube formation, migration (Kim et al, 2009a(Kim et al, , 2009b, and permeability of retinal endothelial cells (Kim et al, 2009a(Kim et al, , 2010. VEGF-mediated inner BRB breakdown might be mediated by VEGFR-2 activation (Kim et al, 2009a).…”

“…According to our previous reports, downregulation and destabilization of HIF-1α protein induced decreases in expression of the VEGF gene (Kim et al, 2001;Oh et al, 2007), leading to inhibition of retinal and choroidal neovascularization (Kim et al, 2008(Kim et al, , 2009b.…”