New CRISPR-Spatial Method Maps Gene Networks in Living Tissues

Scientists have created a powerful new tool called Perturb-FISH that revolutionizes how we study gene function by preserving the spatial context of cells within tissues. Traditional CRISPR screening methods, while effective at identifying gene functions, lose crucial information about how cells interact with their neighbors when tissues are dissociated for analysis.

The research team combined CRISPR gene editing with advanced spatial transcriptomics, allowing them to simultaneously map which genes are turned on or off and identify which specific genes have been targeted by CRISPR—all while maintaining the original tissue architecture. They achieved this by engineering guide RNAs with special amplification sequences that can be detected and decoded directly within intact tissue samples.

Testing their method on immune cells responding to bacterial toxins, the researchers found that Perturb-FISH results closely matched traditional single-cell RNA sequencing approaches, with correlation coefficients above 75-90% for key immune pathway genes. Importantly, the spatial approach revealed additional insights that were missed by conventional methods, including how cell density affects immune responses and how neighboring cells influence each other's genetic programs.

The team demonstrated the method's versatility by studying autism spectrum disorder risk genes in human brain cells derived from stem cells, successfully linking genetic perturbations to both calcium signaling defects and gene expression changes. They also applied Perturb-FISH to three-dimensional tumor models, revealing how genetic modifications in cancer cells affect interactions with infiltrating immune cells.

This advancement could accelerate drug discovery and our understanding of complex diseases by revealing how genetic networks operate within their natural cellular neighborhoods, rather than in isolation.