seqFISH Accurately Detects Transcripts in Single Cells and Reveals Robust Spatial Organization in the Hippocampus

Area of Science:

• Neuroscience
• Genomics
• Molecular Biology

Background:

• Previous studies using multiplexed seqFISH mapped spatial heterogeneity in the CA1 region.
• A concurrent paper questioned the spatial organization findings, citing potential bias from high-expression, non-barcoded genes.

Purpose of the Study:

• To address concerns regarding the influence of gene expression levels on previously reported spatial organization in the CA1.
• To validate the robustness of spatial mapping using genes with lower average abundance.

Main Methods:

• Application of multiplexed seqFISH (single-cell, in situ) to profile gene expression.
• Analysis of spatial gene expression patterns using both high and low average abundance genes.
• Comparative analysis to assess the impact of gene selection on observed spatial structures.

Main Results:

• The robust spatial structure of the CA1 region was confirmed even when analyzing only lower average abundance genes measured by barcoded seqFISH.
• Genes with low average abundance were found to be informative of cell states when expressed strongly in specific subpopulations.
• Single-cell in situ analysis effectively resolves cellular and spatial heterogeneities often lost in population-averaged measurements.

Conclusions:

• The spatial organization of the CA1 region is robust and accurately captured by multiplexed seqFISH, irrespective of average gene abundance.
• Low-abundance genes can be critical for defining cell states and spatial organization.
• Single-cell in situ techniques are essential for a comprehensive understanding of tissue heterogeneity.