Role of endogenous insulin gene enhancer protein ISL-1 in angiogenesis.

Abstract

OBJECTIVE:

To elucidate the role of insulin gene enhancer protein ISL-1 (Islet-1) in angiogenesis and regulation of vascular endothelial growth factor (VEGF) expression in vitro and in vivo.

METHODS:

siRNA targeting Islet-1 was transfected to human umbilical vein endothelial cell lines (HUVECs). The expression of Islet-1 and VEGF in the cultured cells was measured using real-time PCR and immunoblotting. 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide; thiazolyl blue (MTT) assay was used to analyze the proliferation of HUVECs affected by Islet-1. Wound healing and Transwell assays were conducted to assess the motility of HUVECs. The formation of capillary-like structures was examined using growth factor-reduced Matrigel. siRNA targeting Islet-1 was intravitreally injected into the murine model of oxygen-induced retinopathy (OIR). Retinal neovascularization was evaluated with angiography using fluorescein-labeled dextran and then quantified histologically. Real-time PCR and immunoblotting were used to determine whether local Islet-1 silencing affected the expression of Islet-1 and VEGF in murine retinas.

RESULTS:

The expression of Islet-1 and VEGF in HUVECs was knocked down by siRNA. Reduced endogenous Islet-1 levels in cultured cells greatly inhibited the proliferation, migration, and tube formation in HUVECs in vitro. Retinal neovascularization following injection of Islet-1 siRNA was significantly reduced compared with that of the contralateral control eye. Histological analysis indicated that the neovascular nuclei protruding into the vitreous cavity were decreased. Furthermore, the Islet-1 and VEGF expression levels were downregulated in murine retinas treated with siRNA against Islet-1.

CONCLUSIONS:

Reducing the expression of endogenous Islet-1 inhibits proliferation, migration, and tube formation in vascular endothelial cells in vitro and suppresses retinal angiogenesis in vivo. Endogenous Islet-1 regulates angiogenesis via VEGF.

• Authors: Si-Qi Xiong, Hai-Bo Jiang, Yan-Xiu Li, Hai-Bo Li, Hui-Zhuo Xu, Zhen-Kai Wu, Wei Zheng, Xiao-Bo Xia
• Journal: Molecular vision (Mol Vis) Vol. 22 Pg. 1375-1386 ( 2016) ISSN: 1090-0535 [Electronic] United States
• PMID: 27994436 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Drug Combinations
• LIM-Homeodomain Proteins
• Laminin
• Proteoglycans
• RNA, Small Interfering
• Transcription Factors
• VEGFA protein, human
• Vascular Endothelial Growth Factor A
• insulin gene enhancer binding protein Isl-1
• matrigel
• Collagen

Topics

• Animals
• Animals, Newborn
• Blotting, Western
• Cell Movement
• Cell Proliferation
• Cells, Cultured
• Collagen
• Disease Models, Animal
• Drug Combinations
• Fluorescein Angiography
• Human Umbilical Vein Endothelial Cells
• Humans
• Immunoblotting
• LIM-Homeodomain Proteins (physiology)
• Laminin
• Mice
• Mice, Inbred C57BL
• Neovascularization, Physiologic
• Proteoglycans
• RNA, Small Interfering (genetics)
• Real-Time Polymerase Chain Reaction
• Retinal Neovascularization (diagnosis, metabolism)
• Transcription Factors (physiology)
• Transfection
• Vascular Endothelial Growth Factor A (metabolism)