Pleiotrophin gene therapy for peripheral ischemia: evaluation of full-length and truncated gene variants

• Published in: PloS one 2013-04, Vol.8 (4), p.e61413
• Main Authors: Fang, Qizhi, Mok, Pamela Y, Thomas, Anila E, Haddad, Daniel J, Saini, Shereen A, Clifford, Brian T, Kapasi, Neel K, Danforth, Olivia M, Usui, Minako, Ye, Weisheng, Luu, Emmy, Sharma, Rikki, Bartel, Maya J, Pathmanabhan, Jeremy A, Ang, Andrew A S, Sievers, Richard E, Lee, Randall J, Springer, Matthew L
• Format: Article
• Language: English
• Subjects: Analysis; Angiogenesis; Animals; Biology; Bone marrow; Cardiology; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Movement; Cell Transformation, Neoplastic - metabolism; Cells, Cultured; Change detection; Coronary Vessels - pathology; Cytokines - genetics; Cytokines - metabolism; Endoplasmic Reticulum - metabolism; Endoplasmic Reticulum Stress; Gene therapy; Gene transfer; Genetic Therapy; Golgi apparatus; Hindlimb - blood supply; Hindlimb - pathology; Human Umbilical Vein Endothelial Cells - physiology; Humans; Hypoxia; Implantation; Internal medicine; Ischemia; Ischemia - therapy; Male; Medical research; Medicine; Mice; Mice, Nude; Mice, SCID; Muscle, Skeletal - blood supply; Muscle, Skeletal - pathology; Muscles; Myoblasts; Myoblasts - metabolism; Myoblasts - transplantation; Myocardium; Myocardium - pathology; Myocytes, Smooth Muscle - physiology; Neovascularization, Physiologic; Peptide Fragments - genetics; Peptide Fragments - metabolism; Perfusion; Pleiotrophin; Reporter gene; Rodents; Secretion; Skeletal muscle; Skin; Stem cells; Tumorigenesis; Tumors; Vascular endothelial growth factor
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0061413

Pleiotrophin (PTN) is a growth factor with both pro-angiogenic and limited pro-tumorigenic activity. We evaluated the potential for PTN to be used for safe angiogenic gene therapy using the full length gene and a truncated gene variant lacking the domain implicated in tumorigenesis. Mouse myoblasts were transduced to express full length or truncated PTN (PTN or T-PTN), along with a LacZ reporter gene, and injected into mouse limb muscle and myocardium. In cultured myoblasts, PTN was expressed and secreted via the Golgi apparatus, but T-PTN was not properly secreted. Nonetheless, no evidence of uncontrolled growth was observed in cells expressing either form of PTN. PTN gene delivery to myocardium, and non-ischemic skeletal muscle, did not result in a detectable change in vascularity or function. In ischemic hindlimb at 14 days post-implantation, intramuscular injection with PTN-expressing myoblasts led to a significant increase in skin perfusion and muscle arteriole density. We conclude that (1) delivery of the full length PTN gene to muscle can be accomplished without tumorigenesis, (2) the truncated PTN gene may be difficult to use in a gene therapy context due to inefficient secretion, (3) PTN gene delivery leads to functional benefit in the mouse acute ischemic hindlimb model.