New and more efficient multivalent glyco-ligands for asialoglycoprotein receptor of mammalian hepatocytes

Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
Bioorganic & medicinal chemistry (Impact Factor: 2.79). 03/2011; 19(8):2494-500. DOI: 10.1016/j.bmc.2011.03.027
Source: PubMed


New multi-valent, carbohydrate ligands that contain terminal N-acetylgalactosamine (GalNAc) or lactose (Lac) were prepared using a nitrilotriacetic acid (NTA) derivative of L-lysine as scaffold. Tri-valent structures were prepared by attaching an ω-amino glycoside of GalNAc or Lac to each of the three carboxyl groups of N(ε)-protected N(α)-dicarboxymethyl-L-lysine. In addition, a hexa-valent lactoside was synthesized by attaching N(ε)-deprotected trivalent lactoside to each of the carboxyl group of N(α)-(trifluoroacetamido)hexanoyl L-aspartic acid. Tri-valent GalNAc glycosides and the hexa-valent lactoside had high affinity (dissociation constants approaching nM) for rat hepatocytes. The hexa-valent lactoside, after de-N(ε)-protection, was modified with a chelator, diethylenetriaminepentaacetic acid (DTPA), through which a fluorescent or radioactive tag, such as europium or indium, can be firmly attached. Intravenous infusion of (111)Indium-tagged hexa-valent lactoside to rats and mice resulted in nearly exclusive accumulation of radioactivity in the liver.

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    • "In-HL) as an imaging marker of ASGPR. Its physical and chemical properties have been published previously [20] [21]. "
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    ABSTRACT: The asialoglycoprotein receptor on hepatocyte membranes recognizes the galactose residues of glycoproteins. We investigated the specificity, accuracy and threshold value of asialoglycoprotein receptor imaging for estimating liver reserve via scintigraphy using (111)In-hexavalent lactoside in mouse models. (111)In-hexavalent lactoside scintigraphy for asialoglycoprotein receptor imaging was performed on groups of normal mice, orthotopic SK-HEP-1-bearing mice, subcutaneous Hep G2-bearing mice, mice with 20-80% partial hepatectomy and mice with acute hepatitis induced by acetaminophen. Liver reserve was measured by relative liver uptake and compared with normal mice. Asialoglycoprotein receptor blockade was performed via an in vivo asialofetuin competitive binding assay. A total of 73.64±7.11% of the injection dose accumulated in the normal liver tissue region, and radioactivity was barely detected in the hepatoma region. When asialoglycoprotein receptor was blocked using asialofetuin, less than 0.41±0.04% of the injection dose was detected as background in the liver. Asialoglycoprotein receptor imaging data revealed a linear correlation between (111)In-hexavalent lactoside binding and residual liver mass (R(2)=0.8548) in 20-80% of partially hepatectomized mice, demonstrating the accuracy of (111)In-hexavalent lactoside imaging for measuring the functional liver mass. Asialoglycoprotein receptor imaging data in mice with liver failure induced using 600 mg/kg acetaminophen revealed 19-45% liver reserve relative to normal mice and a fatal threshold value of 25% liver reserve. The (111)In-hexavalent lactoside imaging method appears to be a good, specific visual and quantitative predictor of functional liver reserve. The diagnostic threshold for survival was at 25% liver reserve in mice. Copyright © 2015. Published by Elsevier B.V.
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