DEPTOR Deficiency-Mediated mTORc1 Hyperactivation in Vascular Endothelial Cells Promotes Angiogenesis

• Published in: Cellular physiology and biochemistry Vol. 46; no. 2; pp. 520 - 531
• Main Authors: Ding, Yan, Shan, Lanlan, Nai, Wenqing, Lin, Xiaojun, Zhou, Ling, Dong, Xiaoying, Wu, Hongyuan, Xiao, Min, Zhou, Xuejuan, Wang, Linlin, Li, Ting, Fu, You, Lin, Yijun, Jia, Chunhong, Dai, Meng, Bai, Xiaochun
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2018; Cell Physiol Biochem Press GmbH & Co KG
• Subjects: Aging; Angiogenesis; Animals; Aorta - metabolism; Aorta - pathology; Biotechnology; Cancer; Cell cycle; Cell growth; DEPTOR; Diabetic retinopathy; Down-Regulation - drug effects; Heart; HIF-1α; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Immunoglobulins; Infrared imaging systems; Intracellular Signaling Peptides and Proteins - antagonists & inhibitors; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Kidney - metabolism; Kidney - pathology; Kidneys; Kinases; Liver - metabolism; Liver - pathology; Mechanistic Target of Rapamycin Complex 1 - antagonists & inhibitors; Mechanistic Target of Rapamycin Complex 1 - metabolism; Metabolism; Mice; Mice, Knockout; mTORC1; Neovascularization, Physiologic - drug effects; Original Paper; Physiology; Platelet Endothelial Cell Adhesion Molecule-1 - metabolism; Proteins; RNA Interference; RNA, Small Interfering - metabolism; Rodents; Signal Transduction - drug effects; Sirolimus - pharmacology; Stem cells; Up-Regulation - drug effects; Vascular endothelial cell; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; Vascular Endothelial Growth Factor Receptor-2 - metabolism; VEGF; Wound healing; United States > US; China; Germany; Angiogenesis; Vascular endothelial cell; HIF-1α; DEPTOR; mTORC1; VEGF
• ISSN: 1015-8987; 1421-9778
• DOI: 10.1159/000488619

Background/Aims: The mechanistic target of rapamycin (mTOR) signaling pathway is essential for angiogenesis and embryonic development. DEP domain-containing mTOR-interacting protein (DEPTOR) is an mTOR binding protein that functions to inhibit the mTOR pathway In vitro experiments suggest that DEPTOR is crucial for vascular endothelial cell (EC) activation and angiogenic responses. However, knowledge of the effects of DEPTOR on angiogenesis in vivo is limited. This study aimed to determine the role of DEPTOR in tissue angiogenesis and to elucidate the molecular mechanisms. Methods: Cre/loxP conditional gene knockout strategy was used to delete the Deptor gene in mouse vascular ECs. The expression or distribution of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) were detected by immunohistochemical staining or western blot. Tube formation assay was used to measure angiogenesis in vitro. Results: Deptor knockdown led to increased expression of CD31, VEGF and HIF-1α in heart, liver, kidney and aorta. After treatment with rapamycin, their expression was significantly down regulated. In vitro, human umbilical vein endothelial cells (HUVECs) were transfected with DEPTOR-specific small interfering RNA (siRNA), which resulted in a significant increase in endothelial tube formation and migration rates. In contrast, DEPTOR overexpression markedly reduced the expression of CD31, VEGF and HIF-1α. Conclusions: Our findings demonstrated that deletion of the Deptor gene in vascular ECs resulted in upregulated expression of CD31 and HIF-1α, and further stimulated the expression of VEGF which promoted angiogenesis, indicating that disruption of normal angiogenic pathways may occur through hyperactivation of the mTORC1/HIF-1α/VEGF signaling pathway.