Hypothalamic delivery of doxycycline-inducible leptin gene allows for reversible transgene expression and physiological responses.
Our purpose was to incorporate regulation into the recombinant adeno-associated virus encoding leptin by introducing a tet-inducible promotor. This system, TET-Ob, allows for control of leptin gene expression via doxycycline in drinking water. F344XBN rats (aged 4 months) were given a hypothalamic injection of TET-Ob or control virus. During 34 days of doxycycline (doxy) administration to all rats (STAGE 1), TET-Ob rats gained 50.7% less mass, ate 10.4% less food, and had a 77.5% reduction in serum leptin as compared with controls. Doxy was then withdrawn from half of the TET-Ob rats for 32 days (TET-Ob-OFF), while half continued to receive doxy (TET-Ob-ON) (stage 2). During stage 2, TET-Ob-ON rats gained 44.8% less mass than TET-Ob-OFF and ate significantly less food than both TET-Ob-OFF and controls. Serum leptin increased to 83.4% of control values in TET-Ob-OFF, but remained very low in the in TET-Ob-ON. At death, visceral adiposity was 14.5% of controls in TET-Ob-ON animals, but had risen to 76.9% of controls in TET-Ob-OFF. A reversible increase in both leptin signal transduction in the hypothalamus and uncoupling protein expression in brown adipose was recorded. This system allows for more precise regulation of gene therapy-mediated fat loss.
Wilsey
J
J
Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center, Gainesville, FL 32608, USA.
Zolotukhin
S
S
Prima
V
V
Shek
E W
EW
Matheny
M K
MK
Scarpace
P J
PJ
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D004318:Doxycycline / Q000494:pharmacology*; D004435:Eating / Q000502:physiology*; D015870:Gene Expression / Q000187:drug effects; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D007031:Hypothalamus / Q000378:metabolism*; D007473:Ion Channels; D020738:Leptin / Q000097:blood / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics; D014162:Transfection / Q000379:methods; D019076:Transgenes; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D007473:Ion Channels; D020738:Leptin; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D015534:Trans-Activators; D000071256:Uncoupling Protein 1; D004318:Doxycycline