Angiogenesis is induced in a rabbit model of hindlimb ischemia by naked DNA encoding an HIF-1alpha/VP16 hybrid transcription factor.
BACKGROUND
Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription factor that regulates expression of genes involved in O(2) homeostasis, including vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis. We sought to exploit this native adaptive response to hypoxia as a treatment for chronic ischemia.


RESULTS
A hybrid protein consisting of DNA-binding and dimerization domains from the HIF-1alpha subunit and the transactivation domain from herpes simplex virus VP16 protein was constructed to create a strong, constitutive transcriptional activator. After transfection into HeLa, C6, and Hep3B cells, this chimeric transcription factor was shown to activate expression of the endogenous VEGF gene, as well as several other HIF-1 target genes in vitro. The bioactivity of HIF-1alpha/VP16 hybrid gene transfer in vivo was examined in a rabbit model of hindlimb ischemia. Administration of HIF-1alpha/VP16 was associated with significant improvements in calf blood pressure ratio, angiographic score, resting and maximal regional blood flow, and capillary density (all P:<0.01).


CONCLUSIONS
The HIF-1alpha/VP16 hybrid transcription factor is able to promote significant improvement in perfusion of an ischemic limb. These results confirm the feasibility of a novel approach for therapeutic angiogenesis in which neovascularization may be achieved indirectly by use of a transcriptional regulatory strategy.
Vincent
K A
KA
Genzyme Corp, Framingham, MA, USA.
Shyu
K G
KG
Luo
Y
Y
Magner
M
M
Tio
R A
RA
Jiang
C
C
Goldberg
M A
MA
Akita
G Y
GY
Gregory
R J
RJ
Isner
J M
JM
D000792:Angiography; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002460:Cell Line; D003097:Collateral Circulation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000627:therapeutic use; D016228:Endothelial Growth Factors / Q000378:metabolism; D004921:Erythropoietin / Q000096:biosynthesis; D005240:Feasibility Studies; D015316:Genetic Therapy / Q000379:methods; D006400:Hematocrit; D017405:Herpes Simplex Virus Protein Vmw65 / Q000235:genetics; D006614:Hindlimb / Q000098:blood supply* / Q000000981:diagnostic imaging; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007273:Injections, Intramuscular; D007511:Ischemia / Q000628:therapy*; D008222:Lymphokines / Q000378:metabolism; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics / Q000627:therapeutic use; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000627:therapeutic use*; D012039:Regional Blood Flow / Q000187:drug effects; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000627:therapeutic use; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection; D019444:Vaccines, DNA / Q000008:administration & dosage*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; D017405:Herpes Simplex Virus Protein Vmw65; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008222:Lymphokines; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D019444:Vaccines, DNA; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D004921:Erythropoietin