Department of Bioengineering, University of Illinois, Urbana, Illinois 61801, USA.
Am J Physiol Heart Circ Physiol. 2013 Apr 15;304(8):H1085-93. doi: 10.1152/ajpheart.00514.2012. Epub 2013 Feb 1.
VEGF receptor (VEGFR) cell surface localization plays a critical role in transducing VEGF signaling toward angiogenic outcomes, and quantitative characterization of these parameters is critical to advancing computational models for predictive medicine. However, studies to this point have largely examined intact muscle; thus, essential data on the cellular localization of the receptors within the tissue are currently unknown. Therefore, our aims were to quantitatively analyze VEGFR localization on endothelial cells (ECs) from mouse hindlimb skeletal muscles after the induction of hindlimb ischemia, an established model for human peripheral artery disease. Flow cytometry was used to measure and compare the ex vivo surface localization of VEGFR1 and VEGFR2 on CD31(+)/CD34(+) ECs 3 and 10 days after unilateral ligation of the femoral artery. We determined that 3 days after hindlimb ischemia, VEGFR2 surface levels were decreased by 80% compared with ECs from the nonischemic limb; 10 days after ischemia, we observed a twofold increase in surface levels of the modulatory receptor, VEGFR1, along with increased proliferating cell nuclear antigen, urokinase plasminogen activator, and urokinase plasminogen activator receptor mRNA expression compared with the nonischemic limb. The significant upregulation of VEGFR1 surface levels indicates that VEGFR1 indeed plays a critical role in the ischemia-induced perfusion recovery process, a process that includes both angiogenesis and arteriogenesis. The quantification of these dissimilarities, for the first time ex vivo, provides insights into the balance of modulatory (VEGFR1) and proangiogenic (VEGFR2) receptors in ischemia and lays the foundation for systems biology approaches toward therapeutic angiogenesis.
血管内皮生长因子受体 (VEGFR) 的细胞表面定位在转导 VEGF 信号向血管生成结果中起着关键作用，定量描述这些参数对于推进预测医学的计算模型至关重要。然而，到目前为止，这些研究主要集中在完整的肌肉上；因此，目前尚不清楚受体在组织中的细胞定位的基本数据。因此，我们的目的是定量分析在诱导后，来自小鼠后肢骨骼肌的内皮细胞 (EC) 中 VEGFR 的细胞内定位。使用流式细胞术测量和比较 3 天和 10 天后股动脉单侧结扎后，CD31(+) / CD34(+) EC 上 VEGFR1 和 VEGFR2 的体外表面定位。我们发现，与非缺血肢体的 EC 相比，后肢缺血 3 天后，VEGFR2 的表面水平降低了 80%；缺血 10 天后，与非缺血肢体相比，调节性受体 VEGFR1 的表面水平增加了两倍，同时增殖细胞核抗原、尿激酶型纤溶酶原激活物和尿激酶型纤溶酶原激活物受体 mRNA 表达增加。VEGFR1 表面水平的显著上调表明，VEGFR1 确实在缺血诱导的灌注恢复过程中发挥关键作用，这个过程包括血管生成和血管生成。这些差异的定量分析，首次在体外提供了关于调节性 (VEGFR1) 和促血管生成 (VEGFR2) 受体在缺血中的平衡的见解，并为治疗性血管生成的系统生物学方法奠定了基础。
