Therapeutic Targeting of CD47 to Modulate Tissue Responses to Ischemia and RadiationDavid R. Soto-Pantoja1, Jeff S. Isenberg2 and David D. Roberts1*
- *Corresponding Author:
- David D. Roberts
NIH, Building 10 Room 2A33
10 Center Drive, Bethesda
E-mail: [email protected]
Received date: August 27, 2011; Accepted date:September 22, 2011; Published date: September 26, 2011
Citation: Soto-Pantoja DR, Isenberg JS, Roberts DD (2011) Therapeutic Targeting of CD47 to Modulate Tissue Responses to Ischemia and Radiation. J Genet Syndr Gene Ther 2:105. doi:10.4172/2157-7412.1000105
Copyright: © 2011 Soto-Pantoja DR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
CD47 is a widely expressed cell surface receptor that serves as a counter-receptor for signal regulatory protein-? and as a receptor for the secreted matricellular protein thrombospondin-1. Thrombospondin-1 signaling through CD47 regulates cellular signaling pathways that control cell survival, growth, motility, mitochondrial biogenesis, arterial vasoactive responses to physiologic vasodilators and blood flow, and responsiveness to growth factors. Studies employing mice lacking either thrombospondin-1 or CD47 have revealed an important role for this receptorligand interaction in tissue responses to injury and stress. These null mice show enhanced recovery from soft tissue fixed ischemic injuries, ischemia reperfusion injuries, and radiation injuries. These studies have led to development of antisense strategies to locally or globally suppress CD47 gene expression. A translation-blocking CD47 morpholino improves tissue survival in skin flap and hindlimb fixed ischemia models, full thickness skin grafts, and a liver ischemia/reperfusion model of organ transplantation in mice. Furthermore, the benefits of morpholino treatment extend to aged mice and mice with dysregulated fat metabolism that characteristically exhibit impaired recovery from ischemic injuries. Activity of the morpholino was also demonstrated for treatment of ischemic injury in miniature pigs. Treatment with the CD47 morpholino protects mice from major effects of ionizing radiation including alopecia, deterioration of muscle function, soft tissue and cutaneous fibrosis, and loss of hematopoietic stem cells in bone marrow. Remarkably, the same treatment does not protect tumors but instead enhances their ablation by irradiation. We discuss prospects for further development of CD47 antisense therapeutics for clinical applications including reconstructive surgery, organ transplantation, angioplasty, and cancer.