Hypoxia-inducible vascular endothelial growth factor gene therapy using the oxygen-dependent degradation domain in myocardial ischemia.
OBJECTIVE
A hypoxia-inducible VEGF expression system with the oxygen-dependent degradation (ODD) domain was constructed and tested to be used in gene therapy for ischemic myocardial disease.


METHODS
Luciferase and VEGF expression vector systems were constructed with or without the ODD domain: pEpo-SV-Luc (or pEpo-SV-VEGF) and pEpo-SV-Luc-ODD (or pEpo-SV-VEGF-ODD). In vitro gene expression efficiency of each vector type was evaluated in HEK 293 cells under both hypoxic and normoxic conditions. The amount of VEGF protein was estimated by ELISA. The VEGF expression vectors with or without the ODD domain were injected into ischemic rat myocardium. Fibrosis, neovascularization, and cardiomyocyte apoptosis were assessed using Masson's trichrome staining, α-smooth muscle actin (α-SMA) immunostaining, and the TUNEL assay, respectively.


RESULTS
The plasmid vectors containing ODD significantly improved the expression level of VEGF protein in hypoxic conditions. The enhancement of VEGF protein production was attributed to increased protein stability due to oxygen deficiency. In a rat model of myocardial ischemia, the pEpo-SV-VEGF-ODD group exhibited less myocardial fibrosis, higher microvessel density, and less cardiomyocyte apoptosis compared to the control groups (saline and pEpo-SV-VEGF treatments).


CONCLUSIONS
An ODD-mediated VEGF expression system that facilitates VEGF-production under hypoxia may be useful in the treatment of ischemic heart disease.
Kim
Hyun Ah
HA
Department of Bioengineering, College of Engineering, Hanyang University, Seoul 133-791, Korea.
Lim
Soyeon
S
Moon
Hyung-Ho
HH
Kim
Sung Wan
SW
Hwang
Ki-Chul
KC
Lee
Minhyung
M
Kim
Sun Hwa
SH
Choi
Donghoon
D
D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D004921:Erythropoietin / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008156:Luciferases / Q000235:genetics; D008297:Male; D017202:Myocardial Ischemia / Q000473:pathology / Q000628:therapy*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D010100:Oxygen / Q000378:metabolism*; D010957:Plasmids; D055550:Protein Stability; D051381:Rats; D017207:Rats, Sprague-Dawley; D013539:Simian virus 40 / Q000235:genetics; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics*
C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D004921:Erythropoietin; D008156:Luciferases; D010100:Oxygen