Domigan Courtney K, Warren Carmen M, Antanesian Vaspour, Happel Katharina, Ziyad Safiyyah, Lee Sunyoung, Krall Abigail, Duan Lewei, Torres-Collado Antoni X, Castellani Lawrence W, Elashoff David, Christofk Heather R, van der Bliek Alexander M, Potente Michael, Iruela-Arispe M Luisa
Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90024, USA.
Angiogenesis and Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.
J Cell Sci. 2015 Jun 15;128(12):2236-48. doi: 10.1242/jcs.163774. Epub 2015 May 8.
Autocrine VEGF is necessary for endothelial survival, although the cellular mechanisms supporting this function are unknown. Here, we show that--even after full differentiation and maturation--continuous expression of VEGF by endothelial cells is needed to sustain vascular integrity and cellular viability. Depletion of VEGF from the endothelium results in mitochondria fragmentation and suppression of glucose metabolism, leading to increased autophagy that contributes to cell death. Gene-expression profiling showed that endothelial VEGF contributes to the regulation of cell cycle and mitochondrial gene clusters, as well as several--but not all--targets of the transcription factor FOXO1. Indeed, VEGF-deficient endothelium in vitro and in vivo showed increased levels of FOXO1 protein in the nucleus and cytoplasm. Silencing of FOXO1 in VEGF-depleted cells reversed expression profiles of several of the gene clusters that were de-regulated in VEGF knockdown, and rescued both cell death and autophagy phenotypes. Our data suggest that endothelial VEGF maintains vascular homeostasis through regulation of FOXO1 levels, thereby ensuring physiological metabolism and endothelial cell survival.
自分泌血管内皮生长因子(VEGF)对于内皮细胞存活是必需的,尽管支持这一功能的细胞机制尚不清楚。在此,我们表明,即使在内皮细胞完全分化和成熟后,仍需要其持续表达VEGF以维持血管完整性和细胞活力。内皮细胞中VEGF的缺失会导致线粒体碎片化和葡萄糖代谢受抑制,进而导致自噬增加,最终促成细胞死亡。基因表达谱分析表明,内皮VEGF有助于调节细胞周期和线粒体基因簇,以及转录因子FOXO1的几个(但并非全部)靶点。实际上,体外和体内VEGF缺陷的内皮细胞在细胞核和细胞质中FOXO1蛋白水平均升高。在VEGF缺失的细胞中沉默FOXO1可逆转VEGF敲低时几个失调的基因簇的表达谱,并挽救细胞死亡和自噬表型。我们的数据表明,内皮VEGF通过调节FOXO1水平维持血管稳态,从而确保生理代谢和内皮细胞存活。