Fast Metabolic Glycan Labeling for Click-Labeling and Imaging of Sialoglycans in Living Acute Brain Slices from Mice and Human Patients
Xiaoqian Xia, De‐en Sun, Qi Tang, Xianyu Liu, Xinqi Fan, Yi Wan, Shiyong Cui, Xu Zhang, Qingzhu Liu, Yuwu Jiang, Ye Wu, Bo Cheng, Xing Chen
Abstract
Living acute brain slices provide a practical platform for imaging sialylation in human brain pathology. However, the limited lifespan of acute brain slices has impeded the use of metabolic glycan labeling (MGL), which requires long-term incubation of clickable unnatural sugars such as N -azidoacetylmannosamine (ManNAz) to metabolically incorporate azides into sialoglycans. Here, we report a fast variant of MGL (fMGL), in which ManNAz-6-phosphate enables efficient azidosugar incorporation within 12 h by bypassing the bottleneck step in the sialic acid biosynthesis pathway, followed by click-labeling with fluorophores and imaging of sialoglycans in acute brain slices from mice and human patients. In the clinical samples of ganglioglioma, fMGL-based imaging reveals specific upregulation of sialylation in astrocyte-like but not neuron-like tumor cells. In addition, fMGL is integrated with click-expansion microscopy for high-resolution imaging of sialoglycans in brain slices. The fMGL strategy should find broad applications in the tissue imaging of glycans and surgical pathology.