Stabilized HIF‐1α is superior to VEGF for angiogenesis in skeletal muscle via adeno‐associated virus gene transfer

Abstract

Therapeutic angiogenesis provides a potential alternative for the treatment of cardiovascular ischemic diseases. Vascular endothelial growth factor (VEGF) is an important component of the angiogenic response to ischemia. Here we used adeno-associated virus (AAV) gene delivery to skeletal muscle to examine the effects of VEGF vs. a stabilized form of hypoxia-inducible factor-1alpha (HIF-1alpha). The recombinant AAVs were injected into mouse tibialis anterior muscle, and their effects were analyzed by immunohistochemistry and functional assays. These analyses showed that stabilized HIF-1alpha markedly increase capillary sprouting and proliferation, whereas VEGF164 or VEGF120 induced only proliferation of endothelial cells without formation of proper capillary structures. The Evans Blue permeability assay indicated that, unlike VEGF, HIF-1alpha overexpression did not increase vascular leakiness in the transduced muscle. Doppler ultrasound imaging showed that vascular perfusion in the HIF-1alpha treated muscles was significantly enhanced when compared to the controls and not further improved by co-expression of the arteriogenic growth factors angiopoietin-1 or platelet-derived growth factor-B. Our results show that AAV-mediated transduction of a stabilized form of HIF-1alpha can circumvent the problems associated with overexpression of individual angiogenic growth factors. HIF-1alpha should thus offer a potent alternative for pro-angiogenic gene therapy.

Peptide-matrix-mediated gene transfer of an oxygen-insensitive hypoxia-inducible factor-1α variant for local induction of angiogenesis

“…Animals in which wild-type HIF-1␣ was conditionally removed from the endothelium were observed to display a delayed wound healing phenotype, directly suggesting a role in angiogenesis in dermal tissue repair (30). Results from transgenic animals (16), hindlimb (17), and myocardial ischemia (18) models, and skeletal muscle gene delivery morphometric analyses (19) support that a mature angiogenic response may be obtainable through gene therapy with a form of HIF-1␣ that is stable under normoxic conditions.…”

“…In porcine models of myocardial ischemia, HIV-1␣͞VP16 induced improved perfusion and left ventricular function when delivered with an adenoviral vector but not by naked plasmid DNA (18). In skeletal muscle, HIF-1␣͞VP16 was shown to induce a more mature angiogeneic response compared with VEGF when DNA encoding either one was administered with an adeno-associated virus vector (19). These results point to HIF-1␣ being a particularly interesting target protein in angiogenesis, particularly when using a variant form that is stable under normoxia and, thus, is constitutively translocated into the nucleus.…”

HIF-independent regulation of VEGF and angiogenesis by the transcriptional coactivator PGC-1α

“…The generation of fully functional vessels requires the coordinated action of numerous signals, such as PDGF-BB and the angiopoetins 6 . One therapeutic approach to this problem may be to modulate a transcriptional regulator that coordinates these signals appropriately 6,21 . The PGC-1a/ERR-a pathway provides such an opportunity.…”

Synergistic effect of HIF-1α gene therapy and HIF-1-activated bone marrow-derived angiogenic cells in a mouse model of limb ischemia

“…AdCA5, an adenovirus encoding a constitutively active form of HIF-1␣, enhances angiogenesis, arteriogenesis, and the number of circulating angiogenic cells in animal models (4,12,17). Adeno-associated virus transduction of a stabilized form of HIF-1␣ was superior to VEGF in stimulating angiogenesis in skeletal muscle (18). A phase I trial for no-option patients with critical limb ischemia showed no significant adverse effects after administration of adenovirus encoding a HIF-1␣/VP-16 fusion protein (19).…”