Spatial Proximity Sequencing Maps Developmental Dynamics in the Germinal Center.

Area of Science:

• Immunology
• Molecular Biology
• Genomics

Background:

• Spatial protein and interaction profiling is crucial for understanding cellular processes.
• Current methods lack the ability to simultaneously measure proteins, protein complexes, and mRNAs with spatial information.

Purpose of the Study:

• To introduce Spatial Proximity-Sequencing (Sprox-seq), a novel multi-omic technique.
• To simultaneously measure proteins, protein complexes, and mRNAs while recording molecular locations.
• To analyze protein interactions and gene expression in human tonsil tissues and germinal centers.

Main Methods:

• Developed and applied Spatial Proximity-Sequencing (Sprox-seq).
• Profiled 32 proteins, 528 protein interactions, and thousands of mRNAs in human tonsil tissues.
• Mapped protein interactions and correlated them with RNA expression and tissue architecture.

Main Results:

• Sprox-seq successfully mapped protein interactions, recapitulating RNA-defined germinal center architecture.
• Revealed higher protein interaction complexity in the Light zone compared to RNA data.
• Identified distinct B cell maturation pathways based on protein interactions versus RNA.
• Linked spatially-enriched protein complexes to immune regulation and mitotic pathways.
• Captured specific B cell-Follicular Dendritic Cell interactions mediated by VLA-4-VCAM1.

Conclusions:

• Sprox-seq offers a powerful multi-modal view of cell states and molecular interactions within tissues.
• The technique provides a comprehensive tool for studying protein and cellular interactions in spatial contexts.
• Findings advance understanding of B cell development, immune regulation, and tissue organization.