State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, PR China.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, PR China.
Anal Chim Acta. 2018 Dec 18;1039:108-115. doi: 10.1016/j.aca.2018.07.040. Epub 2018 Jul 19.
Exosomal surface glycans play important roles in microvesicle protein sorting and exosome-cell interactions, and also provide promising biomarkers for various diseases. However, in situ detection techniques for exosomal glycans are largely lacking. In this work, an exosomal array is fabricated for probing cancer-related exosomal glycan signatures by lectin recognition-mediated in situ rolling circle assembly of fluorophore-labeled DNA. Different from commonly used lectin array, the proposed strategy enables the direct and amplified conversion of glycan recognition signals to fluorescence detection signals. Focusing on tumor-associated glycans including sialic acids, fucose and truncated O-glycans, the method has been used not only to compare glycan patterns between exosomes with different origins, but also to reveal the specific exosomal glycan characteristics compared to their parent cells. The limits of detection were identified to be 5.4 × 10 and 1.3 × 10 particles mL for HeLa and PANC-1 exosomes, respectively. The dynamic ranges were 4.7 × 10 to 4.7 × 10, 4.7 × 10 to 4.7 × 10 for HeLa exosomes, and 4.7 × 10 to 1.2 × 10, 1.2 × 10 to 4.7 × 10 particles mL for PANC-1 exosomes. The remodeling of exosomal glycans can also be monitored as demonstrated on the cleavage of sialic acids under sialidase treatment. It could be anticipated that this strategy would become a powerful tool for development of exosome-based glyco-biomarkers and elucidation of biological significance of exosomal glycans.
外泌体表面糖基在微泡蛋白分选和外泌体-细胞相互作用中发挥着重要作用，并且也为各种疾病提供了有前途的生物标志物。然而，外泌体糖基的原位检测技术在很大程度上仍然缺乏。在这项工作中，通过凝集素识别介导的荧光标记 DNA 的原位滚环扩增，构建了外泌体阵列来探测与癌症相关的外泌体糖基特征。与常用的凝集素阵列不同，所提出的策略能够直接且放大地将糖基识别信号转换为荧光检测信号。该方法针对包括唾液酸、岩藻糖和截断的 O-聚糖在内的肿瘤相关糖基，不仅用于比较不同来源的外泌体之间的糖型模式，而且用于揭示与亲本细胞相比外泌体的特定糖基特征。该方法对 HeLa 和 PANC-1 外泌体的检测限分别为 5.4×10 和 1.3×10 个颗粒/mL。动态范围分别为 4.7×10 到 4.7×10，4.7×10 到 4.7×10 用于 HeLa 外泌体，4.7×10 到 1.2×10，1.2×10 到 4.7×10 个颗粒/mL 用于 PANC-1 外泌体。在外泌体糖基的切割实验中，如唾液酸酶处理下的唾液酸切割，也可以监测到外泌体糖基的重塑。可以预期，该策略将成为基于外泌体糖基生物标志物的开发和外泌体糖基生物学意义阐明的有力工具。
