title: Methallothionein-3 contributes to vascular endothelial growth factor induction in a mouse model of choroidal neovascularization.
abstract: In the present study, we investigated possible roles of the zinc (Zn)-binding protein metallothionein-3 (MT3) and cellular Zn in a mouse model of laser-induced choroidal neovascularization (CNV) using wild-type (WT) and MT3-knockout (KO) mice. Quantitative RT-PCR was used for the detection of MT3 mRNA. CNV was induced in mice between 8 and 12 weeks of age by disrupting the Bruch's membrane using an argon laser. Fundus photography and fluorescein angiography (FA) were performed 2 weeks following laser photocoagulation. The possible connection between MT3 and vascular endothelial growth factor (VEGF) expression was explored by quantifying VEGF levels in WT and MT3-KO mouse retinas by enzyme-linked immunosorbent assay. The role of Zn in VEGF expression was tested in WT and MT3-KO cells treated with pyrithione, with or without additional Zn, using immunoblotting and fluorescence photomicrography. Following laser-treatment, MT3-KO mice exhibited substantially smaller areas of CNV compared to WT mice. In addition, retinal angiograms revealed less severe fluorescein leakage in MT3-KO mice than in WT mice. On day 14 following the induction of CNV, VEGF expression was markedly increased in WT mice, but remained unchanged in MT3-KO mice. Consistent with the possible involvement of Zn released from MT3, raising intracellular Zn levels increased VEGF levels and activated its receptor, Flk-1, in both WT and MT3-KO retinal cells. Present results demonstrated that neural retinal cells express high levels of MT3, which might play a role in the process of CNV development. Moreover, Zn released from MT3 may contribute to VEGF induction.
authors: Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Korea.
authors: Jeong A
authors: JA
authors: Choi
authors: Jong-uk
authors: JU
authors: Hwang
authors: Young Hee
authors: YH
authors: Yoon
authors: Jae-Young
authors: JY
authors: Koh
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D020256:Choroidal Neovascularization / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005451:Fluorescein Angiography; D005786:Gene Expression Regulation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D015151:Immunoblotting; D007834:Lasers; D008297:Male; D000090023:Metallothionein 3; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011859:Radiography; D012160:Retina / Q000378:metabolism / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
chemical_list: C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D000090023:Metallothionein 3; C000715430:Mt3 protein, mouse; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D015032:Zinc