Site-specific (18)F-labeling of the protein hormone leptin using a general two-step ligation procedure.
The protein hormone leptin acts to regulate body fat and energy expenditure. Resistance to this hormone is implicated in human obesity and its pathophysiological consequences. In order to gain insight into the mechanism of leptin resistance, an (18)F-labeled derivative was developed to study the biodistribution of the hormone using positron emission tomography (PET). A two-step, site specific ligation approach was developed for this purpose, in which an aminooxy-reactive group was incorporated at the C-terminus of leptin using expressed protein ligation (EPL), which was subsequently derivatized with [ (18)F]fluorobenzaldehyde using an aniline-accelerated radiochemical oximation reaction. The modified hormone was shown to be biologically active in vitro and in vivo, and it was applied to PET imaging in ob/ ob mice. These protocols will allow for the routine production of site-specifically (18)F radiolabeled leptin, as well as other proteins, for use in PET imaging in systems from mouse to man.
Laboratory of Synthetic Protein Chemistry, Laboratory of Molecular Genetics, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065, USA.
Robert R
RR
Flavell
Paresh
P
Kothari
Maya
M
Bar-Dagan
Michael
M
Synan
Shankar
S
Vallabhajosula
Jeffrey M
JM
Friedman
Tom W
TW
Muir
Giovanni
G
Ceccarini
D000818:Animals; D001547:Benzaldehydes / Q000737:chemistry; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D007553:Isotope Labeling / Q000379:methods; D007672:Kidney Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D020738:Leptin / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D051379:Mice; D008820:Mice, Obese; D010091:Oximes / Q000737:chemistry; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000493:pharmacokinetics
D001547:Benzaldehydes; D005462:Fluorine Radioisotopes; D020738:Leptin; D010091:Oximes; D019275:Radiopharmaceuticals; C516422:4-fluorobenzaldehyde