Goyal Atul, Gubbiotti Maria A, Chery Daphney R, Han Lin, Iozzo Renato V
From the Department of Pathology, Anatomy, and Cell Biology and the Cancer Cell Biology and Signaling Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and.
the School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104.
J Biol Chem. 2016 Sep 9;291(37):19245-56. doi: 10.1074/jbc.M116.740266. Epub 2016 Jul 19.
Endorepellin, the C-terminal domain of perlecan, is an angiostatic molecule that acts as a potent inducer of autophagy via its interaction with VEGFR2. In this study, we examined the effect of endorepellin on endothelial cells using atomic force microscopy. Soluble endorepellin caused morphological and biophysical changes such as an increase in cell surface roughness and cell height. Surprisingly, these changes were not accompanied by alterations in the endothelial cell elastic modulus. We discovered that endorepellin-induced autophagic flux led to co-localization of mammalian target of rapamycin with LC3-positive autophagosomes. Endorepellin functioned upstream of AMP-activated kinase α, as compound C, an inhibitor of AMP-activated kinase α, abrogated endorepellin-mediated activation and co-localization of Beclin 1 and LC3, thereby reducing autophagic progression. Functionally, we discovered that both endorepellin and Torin 1, a canonical autophagic inducer, blunted ex vivo angiogenesis. We conclude that autophagy is a novel mechanism by which endorepellin promotes angiostasis independent of nutrient deprivation.
内源性血管生成抑制素是基底膜聚糖的C末端结构域，是一种血管生成抑制分子，通过与血管内皮生长因子受体2（VEGFR2）相互作用，作为自噬的有效诱导剂。在本研究中，我们使用原子力显微镜研究了内源性血管生成抑制素对内皮细胞的影响。可溶性内源性血管生成抑制素引起形态和生物物理变化，如细胞表面粗糙度和细胞高度增加。令人惊讶的是，这些变化并未伴随内皮细胞弹性模量的改变。我们发现内源性血管生成抑制素诱导的自噬通量导致雷帕霉素靶蛋白与LC3阳性自噬体共定位。内源性血管生成抑制素在AMP活化蛋白激酶α上游发挥作用，因为AMP活化蛋白激酶α抑制剂化合物C消除了内源性血管生成抑制素介导的Beclin 1和LC3的活化及共定位，从而减少自噬进程。在功能上，我们发现内源性血管生成抑制素和典型自噬诱导剂托瑞米芬均能抑制体外血管生成。我们得出结论，自噬是内源性血管生成抑制素促进血管生成抑制的一种新机制，与营养剥夺无关。
