Analysis of Angiopoietin-related growth factor (AGF) as a potential target for the pharmacological drugs to treat atherosclerotic disease

我们之前报道过过表达血管生成素相关生长因子（AGF）的转基因小鼠通过AGF激活内皮细胞的迁移表现出增强的血管生成，这表明AGF可能是缺血性疾病的一个有吸引力的药物靶点。在此，我们在小鼠后肢缺血模型中确定AGF是否诱导血管生成和改善血流，并确定内皮细胞中AGF信号传导的分子机制。与接受表达gfp的腺病毒的对照组小鼠相比，向缺血肢体肌内注射表达AGF的腺病毒增加了AGF的产生、血管生成和血流量，减少了截肢的必要性。体外分析表明，暴露于AGF的人静脉内皮细胞（HUVECs）通过激活ERK1/2-eNOS信号通路增加NO的产生。此外，agf刺激的eNOS磷酸化、NO的产生和内皮细胞的趋化活性被特异性MEK…More I/2抑制剂（U0126和PD98059）所抑制。最后，在eNOS敲除小鼠的后肢缺血模型中，AGF没有增加血流量，这表明AGF介导的NO上调需要eNOS活性。总的来说，这项研究确定了AGF刺激血管生成的信号机制。这一途径可能在药理学上为缺血性疾病患者的治疗干预提供了希望。此外，我们发现大多数（约80%）AGF缺陷小鼠在胚胎第13天死亡，而存活的AGF缺陷小鼠则出现明显的肥胖、骨骼肌和肝脏的脂质积累以及胰岛素抵抗，同时与对照组相比，能量消耗减少。与此同时，靶向激活AGF的小鼠由于能量消耗增加而表现出瘦弱和胰岛素敏感性增加。它们也免受高脂肪饮食引起的肥胖、胰岛素抵抗和非脂肪组织脂肪变性的影响。通过腺病毒转导的AGF肝脏过度表达，导致血清AGF浓度增加约2.5倍，导致高脂肪饮食小鼠体重显著减轻并增加胰岛素敏感性。本研究确定了AGF作为一种新的肝细胞来源的循环因子，可以抵消肥胖和相关的胰岛素抵抗。少

We previously reported that transgenic mice overexpressing angiopoietin-related growth factor (AGF) exhibit enhanced angiogenesis through AGF-activated migration of endothelial cells, suggesting that AGF might be an attractive drug target in ischemic disease. Here we determine whether AGF induces angiogenesis and ameliorates blood flow in a mouse hind-limb ischemia model and define molecular mechanisms underlying AGF signaling in endothelial cells. Intramuscular injection of adenovirus expressing AGF into the ischemic limb increased AGF production, angiogenesis, and blood flow compared to control mice receiving GFP-expressing adenovirus, decreasing the necessity for limb amputation. In vitro analysis showed that exposure of human venous endothelial cells (HUVECs) to AGF increased NO production by activating the ERK1/2-eNOS signaling pathway. Furthermore, AGF-stimulated phosphorylation of eNOS, production of NO, and chemotactic activity of endothelial cells was abolished by specific MEK … More I/2 inhibitors (U0126 and PD98059). Finally, AGF did not increase blood flow in a hind-limb ischemia model in eNOS knockout mice, indicating that eNOS activity is required for AGF-mediated NO upregulation. Overall this study identifies a signaling mechanism whereby AGF stimulates angiogenesis. This pathway may prove pharmacologically promising for therapeutic interventions for patients with ischemic disease. Furthermore, we show that most (>80%) of the AGF deficient mice die at about embryonic day 13, whereas the surviving AGF-deficient mice develop marked obesity, lipid accumulation in skeletal muscle and liver, and insulin resistance accompanied by reduced energy expenditure relative to controls. In parallel, mice with targeted activation of AGF show leanness and increased insulin sensitivity due to increased energy expenditure. They are also protected from high-fat diet-induced obesity, insulin resistance, and nonadipose tissue steatosis. Hepatic overexpression of AGF by adenoviral transduction, which leads to an approximately 2.5-fold increase in serum AGF concentrations, results in a significant body weight loss and increases insulin sensitivity in mice fed a high-fat diet. This study establishes AGF as a novel hepatocyte-derived circulating factor that counteracts obesity and related insulin resistance. Less