Automation of Multiplexed RNAscope Single-Molecule Fluorescent In Situ Hybridization and Immunohistochemistry for Spatial Tissue Mapping.

In situ transcriptomic methods hold immense promise for spatially resolved mapping of cell types across human tissues. Here, we describe a protocol for automated single-molecule fluorescent in situ hybridization (smFISH) on standard histology sections at high throughput. We focus on the RNAscope smFISH assay that combines branched DNA amplification with tyramide signal amplification (TSA) to obtain high signal-to-noise ratio for tissue imaging. We describe the use of the robotic Leica BOND RX system for automation of liquid handling and the combination of the RNAscope assay with TSA-based immunohistochemistry without the need for specialized demultiplexed imaging.