A cell penetrating heme oxygenase protein protects heart graft against ischemia/reperfusion injury.

Ischemia/reperfusion (I/R) injury is an unavoidable barrier that significantly affects outcome of solid organ transplantation. Here, we establish a protein transduction system to extend graft preservation time and to prevent I/R injury in heart transplantation. We generated a recombinant heme oxygenase-1 (HO-1) protein containing a modified protein transduction domain (PTD). PTD could cross cover cell membrane and carry target molecule to parenchymal cells of cold-preserved heart grafts. The newly generated PTD-HO-1 protein localized mainly in subcellular membrane organelle and nucleus after delivery that significantly prolonged cold preservation of heart grafts. This effect was associated with significantly less endothelial cell activation, less neutrophil and macrophage infiltration in PTD-HO-1-transduced heart grafts after reperfusion as compared with controls. In addition, transduction of PTD-HO-1 protein to heart graft significantly suppressed the I/R injury-associated myocardiocyte apoptosis. The infarct areas of heart graft after I/R injury were significantly reduced after PTD-HO-1 protein treatment. We show here for the first time that PTD can maintain its biological activities during cold preservation. Transduction of cell penetrating HO-1 protein significantly prolongs the cold preservation time and protects the graft from the I/R injury. This approach represents a novel method for the improvement of the overall outcome of organ transplantation.