Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan.
Int J Mol Sci. 2020 May 21;21(10):3635. doi: 10.3390/ijms21103635.
Aberrant angiogenesis is a pathological feature of a number of diseases and arises from the uncoordinated expression of angiogenic factors as response to different cellular stresses. Age-related macular degeneration (AMD), a leading cause of vision loss, can result from pathological angiogenesis. As a mutation in the mitochondrial ferritin (FTMT) gene has been associated with AMD, its possible role in modulating angiogenic factors and angiogenesis was investigated. FTMT is an iron-sequestering protein primarily expressed in metabolically active cells and tissues with high oxygen demand, including retina. In this study, we utilized the human retinal pigment epithelial cell line ARPE-19, both as undifferentiated and differentiated cells. The effects of proinflammatory cytokines, FTMT knockdown, and transient and stable overexpression of FTMT were investigated on expression of pro-angiogenic vascular endothelial growth factor (VEGF) and anti-angiogenic pigment epithelial-derived factor (PEDF). Proinflammatory cytokines induced FTMT and VEGF expression, while NF-κB inhibition significantly reduced FTMT expression. VEGF protein and mRNA expression were significantly increased in FTMT-silenced ARPE-19 cells. Using an in vitro angiogenesis assay with endothelial cells, we showed that conditioned media from FTMT-overexpressing cells had significant antiangiogenic effects. Collectively, our findings indicate that increased levels of FTMT inhibit angiogenesis, possibly by reducing levels of VEGF and increasing PEDF expression. The cellular models developed can be used to investigate if increased FTMT may be protective in angiogenic diseases, such as AMD.
异常血管生成是许多疾病的病理特征，是对不同细胞应激的血管生成因子的不协调表达所致。年龄相关性黄斑变性（AMD）是导致视力丧失的主要原因，可能源于病理性血管生成。由于线粒体铁蛋白（FTMT）基因突变与 AMD 相关，因此研究了其在调节血管生成因子和血管生成中的可能作用。FTMT 是一种主要在代谢活跃的细胞和组织中表达的铁结合蛋白，这些细胞和组织具有高氧需求，包括视网膜。在这项研究中，我们利用人视网膜色素上皮细胞系 ARPE-19，包括未分化细胞和分化细胞，来研究促炎细胞因子、FTMT 敲低以及 FTMT 的瞬时和稳定过表达对促血管生成血管内皮生长因子（VEGF）和抗血管生成色素上皮衍生因子（PEDF）表达的影响。促炎细胞因子诱导 FTMT 和 VEGF 表达，而 NF-κB 抑制则显著降低 FTMT 表达。沉默 ARPE-19 细胞中的 FTMT 可显著增加 VEGF 蛋白和 mRNA 的表达。通过内皮细胞体外血管生成试验，我们表明 FTMT 过表达细胞的条件培养基具有显著的抗血管生成作用。总之，我们的研究结果表明，FTMT 水平升高可抑制血管生成，可能是通过降低 VEGF 水平和增加 PEDF 表达来实现的。所开发的细胞模型可用于研究 FTMT 是否可在血管生成性疾病（如 AMD）中起保护作用。
