Gene therapy of endothelial nitric oxide synthase and manganese superoxide dismutase restores delayed wound healing in type 1 diabetic mice.
BACKGROUND
Nitric oxide (NO) deficiency contributes to diabetic wound healing impairment. The present study tested the hypothesis that increased cutaneous superoxide (O2-) levels in type 1 diabetic mice cause NO deficiency and delayed wound healing.


RESULTS
Wound healing was markedly delayed in streptozotocin-induced type 1 diabetic mice compared with the normal controls. There were significantly reduced levels of endothelial NO synthase (eNOS) protein and constitutive NOS activity in diabetic wounds, whereas O2- levels were markedly increased. A single regimen of cutaneous gene therapy of eNOS or manganese superoxide dismutase (MnSOD) restored such healing delay, with a concomitant suppression of wound O2- levels and augmentation of both eNOS protein and constitutive NOS activity. Gene therapy of MnSOD also increased cutaneous MnSOD activity. Cutaneous O2- levels were also increased in Ins2(Akita) diabetic mice. In vitro glucose treatment of cutaneous tissues from normal mice for 24 hours increased O2- levels in a concentration-dependent manner. The enhanced cutaneous O2- levels induced by high glucose in both normal and diabetic mice were abolished by the NADPH oxidase inhibitor apocynin and the protein kinase C inhibitor chelerythrine. Furthermore, ex vivo gene transfer of dominant-negative HA-tagged N17Rac1, which inhibits NADPH oxidase subunit Rac1, significantly inhibited cutaneous O2- formation induced by high glucose in both normal and Ins2(Akita) diabetic mice.


CONCLUSIONS
These results indicate that hyperglycemia augments cutaneous O2- levels, at least in part, via NADPH oxidase and protein kinase C pathways, resulting in impaired wound healing in type 1 diabetic mice. Gene therapy strategies aimed at restoring cutaneous NO bioavailability may provide an effective means to ameliorate delayed diabetic wound healing.
Luo
Jian-Dong
JD
Department of Pharmacology, Michigan State University, East Lansing 48824-1317, USA.
Wang
Ying-Ying
YY
Fu
Wei-Ling
WL
Wu
Jun
J
Chen
Alex F
AF
D000098:Acetophenones / Q000494:pharmacology; D000256:Adenoviridae / Q000235:genetics; D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D001682:Biological Availability; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D004790:Enzyme Induction; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000627:therapeutic use*; D005947:Glucose / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000502:physiology*; D009569:Nitric Oxide / Q000172:deficiency / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000032:analysis; D018384:Oxidative Stress; D010617:Phenanthridines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D015398:Signal Transduction; D012867:Skin / Q000737:chemistry / Q000293:injuries; D013482:Superoxide Dismutase / Q000235:genetics / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology*; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000502:physiology
D000098:Acetophenones; D000470:Alkaloids; D053119:Benzophenanthridines; D009573:Nitrites; D010617:Phenanthridines; D011993:Recombinant Fusion Proteins; D013481:Superoxides; D009569:Nitric Oxide; C056165:acetovanillone; C016299:chelerythrine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D011493:Protein Kinase C; C499134:Rac1 protein, rat; D020830:rac1 GTP-Binding Protein; D005947:Glucose