Kaltner H, Lips K S, Reuter G, Lippert S, Sinowatz F, Gabius H J
Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität, München, Germany.
Histol Histopathol. 1997 Oct;12(4):945-60.
The display of cellular oligosaccharide chains is known to undergo marked developmental changes, as monitored histochemically with plant lectins. In conjunction with endogenous lectins respective ligand structures may have a functional role during fetal development. The assumption of a recognitive, functionally productive interplay prompts the study of the expression of a tissue lectin and of lectin-reactive glycoconjugates concomitantly. Focusing on common beta-galactosides as constituents of oligosaccharide chains and the predominant member of the family of galectins in mammals, namely galectin-1, the question therefore is addressed as to whether expression of lectin and lectin-reactive glycoconjugates exhibits alterations, assessed in three morphologically defined fetal stages and in adult bovine organs. Using a sandwich ELISA, the level of the rather ubiquitous galectin-1 is mostly increased in adult organs relative to respective fetal stages, except for the case of kidney. This developmental course is seen rather seldom, when the amounts of lectin-reactive glycoproteins or glycolipids are quantitated in solid-phase assays after tissue homogenization. Western blotting, combined with probing by labeled galectin-1, discloses primarily quantitative changes in the reactivity of individual glycoproteins. Performing the same assays on extract aliquots with a plant agglutinin, namely the galactoside-binding mistletoe lectin, whose fine specificity is different from galectin-1, its reduced extent of binding in solid-phase assays and the disparate profile of lectin-reactive glycoproteins reveal a non-uniform developmental alteration within the group of structural variants of beta-galactosides. Although sample preparation can affect ligand preservation and/or presentation and thus restricts the comparability of biochemical and histochemical results, especially for soluble reactants, the histochemical studies on frozen and paraffin-embedded sections of bovine heart, kidney and liver demonstrate that the localization of the galectin and of lectin-reactive epitopes can show a similar distribution, as seen in liver and heart, with organ-typical quantitative changes of a rather similar staining profile (heart, kidney) or notable changes in the spatial distribution (liver) in the course of development. This report emphasizes the potential value of combined monitoring of the lectin and its potential in vivo ligands to contribute to eventually unravel organ-related function(s) of a tissue lectin.
已知细胞寡糖链的展示会经历显著的发育变化，这可以通过植物凝集素进行组织化学监测。与内源性凝集素相结合，各自的配体结构可能在胎儿发育过程中发挥功能作用。基于存在识别性、功能上有效的相互作用这一假设，促使人们同时研究一种组织凝集素和凝集素反应性糖缀合物的表达。由于寡糖链的组成成分常见的β - 半乳糖苷以及哺乳动物半乳糖凝集素家族的主要成员——半乳糖凝集素 -1，因此研究的问题是，在三个形态学定义的胎儿阶段以及成年牛器官中，凝集素和凝集素反应性糖缀合物的表达是否会出现变化。使用夹心酶联免疫吸附测定法（ELISA），相对各自的胎儿阶段，相当普遍存在的半乳糖凝集素 -1水平在成年器官中大多会升高，但肾脏情况除外。当在组织匀浆后的固相测定中对凝集素反应性糖蛋白或糖脂的量进行定量时，这种发育过程很少见。蛋白质印迹法结合用标记的半乳糖凝集素 -1进行探测，主要揭示了各个糖蛋白反应性的定量变化。用一种植物凝集素，即具有半乳糖苷结合能力的槲寄生凝集素，对提取物等分试样进行相同的测定，其精细特异性与半乳糖凝集素 -1不同，在固相测定中其结合程度降低以及凝集素反应性糖蛋白的不同图谱表明，β - 半乳糖苷结构变体组内存在不均匀的发育变化。尽管样品制备会影响配体的保存和/或呈现，从而限制了生化和组织化学结果的可比性，尤其是对于可溶性反应物，但对牛心脏、肾脏和肝脏的冷冻切片及石蜡包埋切片进行的组织化学研究表明，半乳糖凝集素和凝集素反应性表位的定位可以呈现相似的分布，如在肝脏和心脏中所见，在发育过程中具有器官典型的定量变化，染色图谱较为相似（心脏、肾脏）或空间分布有显著变化（肝脏）。本报告强调了联合监测凝集素及其体内潜在配体对于最终揭示组织凝集素的器官相关功能的潜在价值。
