Chao-Cheng Huang1,2, Hsiao-Mei Kuo3,4, Pei-Chang Wu5, Shih-Hsuan Cheng1,6, Tzu-Ting Chang4,7, Yi-Chen Chang8,9, Mei-Lang Kung10, Deng-Chyang Wu11,6, Jiin-Haur Chuang12, Ming-Hong Tai13,14,15,16,17,18,19. 1. Biobank and Tissue Bank and Department of Pathology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan. 2. Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Kaohsiung, Taiwan. 3. Center for Neuroscience, National Sun Yat-Sen University, Kaohsiung, Taiwan. 4. Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan. 5. Departments of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan. 6. Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 7. Institute of Chemistry, Academia Sinica, Taipei, Taiwan. 8. Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan. 9. Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei, Taiwan. 10. Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan. 11. Center for Stem Cell Research, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 12. Division of Pediatric Surgery, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 833, Taiwan. jhchuang@adm.cgmh.org.tw. 13. Center for Neuroscience, National Sun Yat-Sen University, Kaohsiung, Taiwan. minghongtai@gmail.com. 14. Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan. minghongtai@gmail.com. 15. Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan. minghongtai@gmail.com. 16. Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei, Taiwan. minghongtai@gmail.com. 17. Center for Stem Cell Research, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. minghongtai@gmail.com. 18. Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. minghongtai@gmail.com. 19. Institute of Biomedical Sciences, National Sun Yat-Sen University, 70 Lien-Hai Rd, Kaohsiung, 804, Taiwan. minghongtai@gmail.com.
Abstract
AIM: Delta-like 1 homolog (DLK1) is a non-canonical ligand of Notch signaling, which plays a pivotal role in vascular development and tumor angiogenesis. This study aimed to elucidate the function and mechanism of DLK1 in angiogenesis. METHODS AND RESULTS: By using in situ hybridization and immunohistochemical studies, expression analysis revealed a unique vascular tropism of DLK1 in vasculature of neuroblastoma and vascular tumors. Thus, it was hypothesized that DLK1 may be cleaved and then bound to endothelial cells, thereby regulating the endothelial function. To test such hypothesis, soluble DLK1 encompassing DLK1 extracellular domain (DLK1-EC) was generated and validated by its inhibitory function in adipogenesis assay. Recombinant DLK1-EC exhibited the preferential binding capability toward endothelial cells and stimulated the microvessels sprouting in aorta rings. Above all, implantation of DLK1-EC dose-dependently elicited the cornea neovascularization in rats. By using various angiogenesis assays, it was delineated that DLK1-EC stimulated the angiogenesis by promoting the proliferation, motility and tube formation of endothelial cells. By immunoblot and luciferase analysis, it was elucidated that DLK1-EC enhanced the expression and activities of Notch1/Akt/eNOS/Hes-1 signaling in dose- and time-dependent manners. Pharmaceutical blockage of Notch signaling using γ-secretase inhibitor DAPT abrogated the DLK1-EC-induced endothelial migration and Hes-1-driven luciferase activities. Furthermore, Notch1 inactivation by neutralizing antibodies or RNA interference reversed the DLK1-EC-induced angiogenesis. CONCLUSIONS: The present study unveils the pro-angiogenic function and mechanism of soluble DLK1 through activation of Notch1 signaling in endothelial cells.
AIM: Delta-like 1 homolog (DLK1) is a non-canonical ligand of Notch signaling, which plays a pivotal role in vascular development and tumor angiogenesis. This study aimed to elucidate the function and mechanism of DLK1 in angiogenesis. METHODS AND RESULTS: By using in situ hybridization and immunohistochemical studies, expression analysis revealed a unique vascular tropism of DLK1 in vasculature of neuroblastoma and vascular tumors. Thus, it was hypothesized that DLK1 may be cleaved and then bound to endothelial cells, thereby regulating the endothelial function. To test such hypothesis, soluble DLK1 encompassing DLK1 extracellular domain (DLK1-EC) was generated and validated by its inhibitory function in adipogenesis assay. Recombinant DLK1-EC exhibited the preferential binding capability toward endothelial cells and stimulated the microvessels sprouting in aorta rings. Above all, implantation of DLK1-EC dose-dependently elicited the cornea neovascularization in rats. By using various angiogenesis assays, it was delineated that DLK1-EC stimulated the angiogenesis by promoting the proliferation, motility and tube formation of endothelial cells. By immunoblot and luciferase analysis, it was elucidated that DLK1-EC enhanced the expression and activities of Notch1/Akt/eNOS/Hes-1 signaling in dose- and time-dependent manners. Pharmaceutical blockage of Notch signaling using γ-secretase inhibitor DAPT abrogated the DLK1-EC-induced endothelial migration and Hes-1-driven luciferase activities. Furthermore, Notch1 inactivation by neutralizing antibodies or RNA interference reversed the DLK1-EC-induced angiogenesis. CONCLUSIONS: The present study unveils the pro-angiogenic function and mechanism of soluble DLK1 through activation of Notch1 signaling in endothelial cells.
Authors: Jorge Lopez-Tello; Zoe Schofield; Amanda N Sferruzzi-Perri; Lindsay J Hall; Raymond Kiu; Matthew J Dalby; Douwe van Sinderen; Gwénaëlle Le Gall Journal: Cell Mol Life Sci Date: 2022-06-28 Impact factor: 9.207