Laube Markus, Kniess Torsten, Neuber Christin, Haase-Kohn Cathleen, Pietzsch Jens
Department of Radiopharmaceutical and Chemical Biology, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany.
Department of GMP Radiopharmaceuticals Production, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany.
Methods Mol Biol. 2019;1929:461-485. doi: 10.1007/978-1-4939-9030-6_29.
The interaction of S100 proteins (S100s), a multigenic family of Ca-binding and Ca-modulated proteins, with pattern recognition receptors, e.g., Toll-like receptors (TLRs), the receptor for advanced glycation end products (RAGE), or scavenger receptors (SR), is hypothesized to be of high relevance in the pathogenesis of various diseases. This includes chronic inflammatory conditions, atherosclerosis, cardiomyopathies, neurodegeneration, and progression of cancers. However, data concerning the role of circulating S100s in these pathologies are scarce. One reason for this is the shortage of suitable radiolabeling methods for direct assessment of the metabolic fate of circulating S100s in vivo. We report a radiotracer approach using radiolabeling of recombinant human S100s with the positron emitter fluorine-18 (F) by conjugation with N-succinimidyl 4-[F]fluorobenzoate ([F]SFB). The methodological radiochemical part focuses on an optimized and automated synthesis of [F]SFB comprising HPLC purification to achieve higher chemical purity. The respective radioligands, [F]fluorobenzoylated S100s ([F]FB-S100s), were obtained with appropriate radiochemical purities, yields, and effective molar activities. Biological applications comprise cell and tissue binding experiments in vitro, biodistribution and metabolite studies in rodents in vivo/ex vivo, and dynamic positron emission tomography studies using dedicated small animal PET systems. Radiolabeling of S100s with F and, particularly, the use of small animal PET provide novel probes to delineate both their metabolic fate and the functional expression of their specific receptors under normal and pathophysiological conditions in rodent models of disease.
S100蛋白（S100s）是一个多基因家族的钙结合和钙调节蛋白，它与模式识别受体相互作用，例如Toll样受体（TLRs）、晚期糖基化终产物受体（RAGE）或清道夫受体（SR），据推测，这在各种疾病的发病机制中具有高度相关性。这包括慢性炎症性疾病、动脉粥样硬化、心肌病、神经退行性变以及癌症进展。然而，关于循环S100s在这些病理过程中作用的数据却很少。造成这种情况的一个原因是缺乏合适的放射性标记方法来直接评估循环S100s在体内的代谢命运。我们报告了一种放射性示踪方法，即通过与N - 琥珀酰亚胺基4 - [F]氟苯甲酸酯（[F]SFB）偶联，用正电子发射体氟 - 18（F）对重组人S100s进行放射性标记。方法学的放射化学部分重点在于[F]SFB的优化和自动化合成，包括通过高效液相色谱（HPLC）纯化以实现更高的化学纯度。相应的放射性配体，即[F]氟苯甲酰化的S100s（[F]FB - S100s），以适当的放射化学纯度、产率和有效摩尔活性获得。生物学应用包括体外细胞和组织结合实验、体内/体外啮齿动物的生物分布和代谢物研究，以及使用专用小动物正电子发射断层扫描（PET）系统进行的动态正电子发射断层扫描研究。用F对S100s进行放射性标记，特别是使用小动物PET，提供了新的探针，以描绘它们在正常和病理生理条件下在啮齿动物疾病模型中的代谢命运及其特定受体的功能表达。
