Supplement of tetrahydrobiopterin by a gene transfer of GTP cyclohydrolase I cDNA improves vascular dysfunction in insulin-resistant rats.
Deficiency of tetrahydrobiopterin (BH4) in the vascular tissue contributes to endothelial dysfunction in the insulin-resistant state. We intended to develop a new gene transfer method by overexpression of its biosynthetic enzyme, GTP cyclohydrolase I (GTP-CH1). The GTP-CH1 cDNA was inserted into a pCAGGS vector, and then plasmid DNA was mixed with atelocollagen, and the aliquot was injected into thigh muscles of insulin-resistant Zucker fatty rats. After 4 weeks, pteridine derivative levels, superoxide anion (O2-), activity of endothelial nitric oxide synthase (eNOS), and endothelium-dependent relaxation were evaluated in the aortas obtained from Zucker lean or fatty rats. The BH4 contents and GTP-CH1 activity in Zucker fatty rats were 50%-55% less than those of Zucker lean rats. However, those impairments were significantly improved by a plasmid DNA injection, and aortic BH4 content reached more than 80% of the level of Zucker lean rats. Increased A23187-stimulated O2- production as well as decreased eNOS activity and endothelial function in insulin-resistant Zucker fatty rats were improved by a plasmid DNA injection to a level similar to that in Zucker lean rats. These findings suggest that intramuscular GTP-CH1 gene transfer using atelocollagen serves as a useful method of long-term systemic delivery of BH4 and the treatment of endothelial dysfunction.
Shinozaki
Kazuya
K
Department of Pharmacology, Shiga University of Medical Science, Otsu, Japan.
Nishio
Yoshihiko
Y
Yoshida
Yuichi
Y
Koya
Daisuke
D
Ayajiki
Kazuhide
K
Masada
Masahiro
M
Kashiwagi
Atsunori
A
Okamura
Tomio
T
D000273:Adipose Tissue / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D001708:Biopterins / Q000031:analogs & derivatives* / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D018076:DNA, Complementary / Q000235:genetics*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology*; D006136:GTP Cyclohydrolase / Q000235:genetics* / Q000378:metabolism; D018014:Gene Transfer Techniques; D066298:In Vitro Techniques; D007273:Injections, Intramuscular; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D051381:Rats; D011924:Rats, Zucker; D013481:Superoxides / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
D018076:DNA, Complementary; D013481:Superoxides; D001708:Biopterins; D052250:Nitric Oxide Synthase Type III; D006136:GTP Cyclohydrolase; C003402:sapropterin