|
|
||||||||
Laboratory of Developmental Biology and Repair and Department of Surgery, New York University Medical Center, New York, New York, 10016
Angiogenesis is essential for the increased delivery of oxygen and nutrients required for the reparative processes of bone healing. Vascular endothelial growth factor (VEGF), a potent angiogenic growth factor, has been implicated in this process. We have previously shown that hypoxia specifically and potently regulates the expression of VEGF by osteoblasts. However, the molecular mechanisms governing this interaction remain unknown. In this study, we hypothesized that the hypoxic regulation of VEGF expression by osteoblasts occurs via an oxygen-sensing mechanism similar to the regulation of the erythropoietin gene (EPO). To test this hypothesis, we examined the kinetics of oxygen concentration on osteoblast VEGF expression. In addition, we analyzed the effects of nickel and cobalt on the expression of VEGF in osteoblastic cells because these metallic ions mimic hypoxia by binding to the heme portion of oxygen-sensing molecules. Our results indicated that hypoxia potently stimulates VEGF mRNA expression. In addition, we found that nickel and cobalt both stimulate VEGF gene expression in a similar time- and dose-dependent manner, suggesting the presence of a hemelike oxygen-sensing mechanism similar to that of the EPO gene. Moreover, actinomycin D, cycloheximide, dexamethasone, and mRNA stabilization studies collectively established that this regulation is predominantly transcriptional, does not require de novo protein synthesis, and is not likely mediated by the transcriptional activator AP-1. These studies demonstrate that hypoxia, nickel, and cobalt regulate VEGF expression in osteoblasts via a similar mechanism, implicating the involvement of a heme-containing oxygen-sensing molecule. This may represent an important mechanism of VEGF regulation leading to increased angiogenesis in the hypoxic microenvironment of healing bone.
bone repair; osteogenesis; angiogenesis
This article has been cited by other articles:
![]() |
J. Sangerman, M. S. Lee, X. Yao, E. Oteng, C.-H. Hsiao, W. Li, S. Zein, S. F. Ofori-Acquah, and B. S. Pace Mechanism for fetal hemoglobin induction by histone deacetylase inhibitors involves {gamma}-globin activation by CREB1 and ATF-2 Blood, November 15, 2006; 108(10): 3590 - 3599. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Jarrahy, W. Huang, G. H. Rudkin, J. M. Lee, K. Ishida, M. D. Berry, M. Sukkarieh, B. M. Wu, D. T. Yamaguchi, and T. A. Miller Osteogenic differentiation is inhibited and angiogenic expression is enhanced in MC3T3-E1 cells cultured on three-dimensional scaffolds Am J Physiol Cell Physiol, August 1, 2005; 289(2): C408 - C414. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Furumatsu, Z. N. Shen, A. Kawai, K. Nishida, H. Manabe, T. Oohashi, H. Inoue, and Y. Ninomiya Vascular Endothelial Growth Factor Principally Acts as the Main Angiogenic Factor in the Early Stage of Human Osteoblastogenesis J. Biochem., May 1, 2003; 133(5): 633 - 639. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Pham, T. Uchida, C. Planes, L. B. Ware, R. Kaner, M. A. Matthay, and C. Clerici Hypoxia upregulates VEGF expression in alveolar epithelial cells in vitro and in vivo Am J Physiol Lung Cell Mol Physiol, November 1, 2002; 283(5): L1133 - L1142. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. F. Abcouwer, P. L. Marjon, R. K. Loper, and D. L. Vander Jagt Response of VEGF Expression to Amino Acid Deprivation and Inducers of Endoplasmic Reticulum Stress Invest. Ophthalmol. Vis. Sci., August 1, 2002; 43(8): 2791 - 2798. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Street, M. Bao, L. deGuzman, S. Bunting, F. V. Peale Jr., N. Ferrara, H. Steinmetz, J. Hoeffel, J. L. Cleland, A. Daugherty, et al. Vascular endothelial growth factor stimulates bone repair by promoting angiogenesis and bone turnover PNAS, July 23, 2002; 99(15): 9656 - 9661. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. S. Gross, N. Akeno, T. L. Clemens, S. Komarova, S. Srinivasan, D. A. Weimer, and S. Mayorov Physiological and Genomic Consequences of Intermittent Hypoxia: Selected Contribution: Osteocytes upregulate HIF-1{alpha} in response to acute disuse and oxygen deprivation J Appl Physiol, June 1, 2001; 90(6): 2514 - 2519. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Shi, X. Le, J. L. Abbruzzese, Z. Peng, C.-N. Qian, H. Tang, Q. Xiong, B. Wang, X.-C. Li, and K. Xie Constitutive Sp1 Activity Is Essential for Differential Constitutive Expression of Vascular Endothelial Growth Factor in Human Pancreatic Adenocarcinoma Cancer Res., May 1, 2001; 61(10): 4143 - 4154. [Abstract] [Full Text] |
||||
![]() |
J. A. Spector, B. J. Mehrara, J. A. Greenwald, P. B. Saadeh, D. S. Steinbrech, P. J. Bouletreau, L. P. Smith, and M. T. Longaker Osteoblast expression of vascular endothelial growth factor is modulated by the extracellular microenvironment Am J Physiol Cell Physiol, January 1, 2001; 280(1): C72 - C80. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |