Molecular Imaging of RNA Interference Therapy Targeting PHD2 for Treatment of Myocardial Ischemia
Coronary artery disease is the number one cause of morbidity and mortality in the Western world. It typically occurs when heart muscle receives inadequate blood supply due to rupture of atherosclerotic plaques. During ischemia, up-regulation of hypoxia inducible factor-1 alpha (HIF-1α) transcriptional factor can activate several downstream angiogenic genes. However, HIF-1α is naturally degraded by prolyl hydroxylase-2 (PHD2) protein. Recently, we cloned the mouse PHD2 gene by comparing the homolog gene in human and rat. The best candidate shRNA sequence for inhibiting PHD2 was inserted behind H1 promoter, followed by a separate hypoxia response element (HRE)-incorporated promoter driving a firefly luciferase (Fluc) reporter gene. This construct allowed us to monitor gene expression noninvasively and was used to test the hypothesis that inhibition of PHD2 by short hairpin RNA interference (shRNA) can lead to significant improvement in angiogenesis and contractility as revealed by in vitro and in vivo experiments.
Key wordsRNA interference Molecular imaging Hypoxia inducible factor (HIF) Prolyl hydroxylases (PHD) Ischemic heart disease
This work was supported in part by grants from the NIH HL095571 (JCW), NIH HL093172 (JCW), and AHA Western Postdoctoral Fellowship (MH).
- 1.Rosamond, W., Flegal, K., Friday, G., Furie, K., Go, A., Greenlund, K., Haase, N., Ho, M., Howard, V., Kissela, B., Kittner, S., Lloyd-Jones, D., McDermott, M., Meigs, J., Moy, C., Nichol, G., O’Donnell, C. J., Roger, V., Rumsfeld, J., Sorlie, P., Steinberger, J., Thom, T., Wasserthiel-Smoller, S. and Hong, Y. (2007) Heart disease and stroke statistics--2007 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 115, e69–e171.PubMedCrossRefGoogle Scholar
- 6.Luttun, A., Tjwa, M., Moons, L., Wu, Y., Angelillo-Scherrer, A., Liao, F., Nagy, J. A., Hooper, A., Priller, J., De Klerck, B., Compernolle, V., Daci, E., Bohlen, P., Dewerchin, M., Herbert, J. M., Fava, R., Matthys, P., Carmeliet, G., Collen, D., Dvorak, H. F., Hicklin, D. J. and Carmeliet, P. (2002) Revascularization of ischemic tissues by PlGF treatment, and inhibition of tumor angiogenesis, arthritis and atherosclerosis by anti-Flt1. Nat Med 8, 831–840.PubMedGoogle Scholar
- 8.Fukuda, R., Hirota, K., Fan, F., Jung, Y. D., Ellis, L. M. and Semenza, G. L. (2002) Insulin-like growth factor 1 induces hypoxia-inducible factor 1-mediated vascular endothelial growth factor expression, which is dependent on MAP kinase and phosphatidylinositol 3-kinase signaling in colon cancer cells. J Biol Chem 277, 38205–38211.PubMedCrossRefGoogle Scholar
- 21.Cao, F., Lin, S., Xie, X., Ray, P., Patel, M., Zhang, X., Drukker, M., Dylla, S. J., Connolly, A. J., Chen, X., Weissman, I. L., Gambhir, S. S. and Wu, J. C. (2006) In vivo visualization of embryonic stem cell survival, proliferation, and migration after cardiac delivery. Circulation 113, 1005–1014.PubMedCrossRefGoogle Scholar