Magnetic resonance imaging of inducible E-selectin expression in human endothelial cell culture.
Covalent conjugates of the cross-linked iron oxide nanoparticles (CLIO) and high-affinity (K(d)(app) = 8.5 nM) anti-human E-selectin (CD62E) F(ab')(2) fragments were prepared and tested in vitro to establish feasibility of endothelial proinflammatory marker magnetic resonance (MR) imaging. The conjugates were obtained by using thiol-disulfide exchange reaction between 3-(2-pyridyl)propionyl-CLIO and S-acetylthioacetate-modified F(ab')(2) fragments. The purified CLIO-F(ab')(2) conjugates (average hydrodynamic diameter 40.6 nm) were used in experiments with the live human endothelial umbilical vein cells (HUVEC). Cells treated with IL-1 beta expressed E-selectin and showed a 100-200 times higher binding of CLIO particles (83-104 ng iron/million cells) than control cells. The binding resulted in a high superparamagnetism of HUVEC with the transverse water proton relaxation time (T2) decrease to 30-40 ms in cell precipitates. Cells did not bind/internalize CLIO-F(ab')(2) conjugates prepared using a control fragment or nonconjugated iron oxide particles before or after treatment with IL-1 beta. MR imaging of cells showed a highly specific T2-weighted signal darkening associated with cells treated with IL-1 beta and incubated with anti-E selectin. Demonstration of MR imaging of E-selectin expression justifies further development of MR-targeted agents for monitoring tumor vascular endothelial proliferation, angiogenesis, and atherosclerosis.
Kang
Hye Won
HW
Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA.
Josephson
Lee
L
Petrovsky
Alexander
A
Weissleder
Ralph
R
Bogdanov
Alexei
A
D002478:Cells, Cultured; D003432:Cross-Linking Reagents; D019040:E-Selectin / Q000096:biosynthesis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005290:Ferric Compounds; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry; D007202:Indicators and Reagents; D007375:Interleukin-1 / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D010316:Particle Size
D003432:Cross-Linking Reagents; D019040:E-Selectin; D005290:Ferric Compounds; D007140:Immunoglobulin Fab Fragments; D007202:Indicators and Reagents; D007375:Interleukin-1; C000499:ferric oxide