3D reconstruction from serial sections of spatial transcriptomics and H&E images¶

In this section, we will guide you through the process of creating a 3D reconstruction from serial sections of spatial transcriptomics (ST) and H&E images using the Spatial Transcriptomics ImgLib2/Imaging Project (STIM, v0.2.0). This reconstruction allows you to gain a comprehensive understanding of your biological samples in three dimensions.

Creation of csv files¶

Use the provided script

openst to_3d_registration --args --metadata=<where_to_write_metadata>

Conversion to n5 format¶

Convert the coordinate and gene expression information of these datasets into the n5 format, which is optimized for efficient image processing, using the st-resave function.

STIMBINS="/home/dleonpe/data/bin"
STIMINFILES="/data/rajewsky/home/dleonpe/projects/openst_paper/data/2_downstream/fc_sts_63/aligned_sections/1_input"
STIMOUTFILES="/data/rajewsky/home/dleonpe/projects/openst_paper/data/2_downstream/fc_sts_63/aligned_sections/2_stim_dataset"
FNAME="stitched_spots_merged_aligned_10px_GAN_segmented.h5ad."

$STIMBINS/st-resave \
    -i "$STIMINFILES/fc_sts_63_2_${FNAME}locations.csv,$STIMINFILES/fc_sts_63_2_${FNAME}genes.csv,fc_sts_63_02" \
    -i "$STIMINFILES/fc_sts_63_3_${FNAME}locations.csv,$STIMINFILES/fc_sts_63_3_${FNAME}genes.csv,fc_sts_63_03" \
    -o "$STIMOUTFILES/fc_sts_63.n5" \
    --normalize

Pairwise alignment¶

Utilize the st-align-pairs function to perform pairwise alignment of three sections below and above each section (r=3). This function creates image channels of gene expression for prespecified genes, aggregated per cell as a Gauss rendering around centroids, parametrized with a smoothness factor.

STIMBINS="/home/dleonpe/data/bin"
STIMOUTFILES="/data/rajewsky/home/dleonpe/projects/openst_paper/data/2_downstream/fc_sts_63/aligned_sections/2_stim_dataset"

# 2. Run pairwise alignment
$STIMBINS/st-align-pairs \
     -i "$STIMOUTFILES/fc_sts_63.n5" \
     --scale 0.03 \
     -r 3 \
     --hidePairwiseRendering \
     --overwrite \
     -sf 4.0 \
     --minNumInliers 15 \
     --numGenes 0 \
     -g 'KRT6A,KRT6B,S100A2,LYZ,CD74,IGKC,IGHG1,IGHA1,JCHAIN,CD74,AMTN'
     #--numGenes 20 \

Feature Filtering and Global Alignment¶

Filter the resulting set of feature matches between pairs of sections using an affine model. Configure the st-align-pairs function with appropriate parameters, such as --minNumInliers 15, --scale 0.03, and -sf 4.0 (smoothness factor).

STIMBINS="/home/dleonpe/data/bin"
STIMOUTFILES="/data/rajewsky/home/dleonpe/projects/openst_paper/data/2_downstream/fc_sts_63/aligned_sections/2_stim_dataset"

$STIMBINS/st-align-global \
     -i "$STIMOUTFILES/fc_sts_63.n5" \
     --skipICP \
     -g 'KRT6A,KRT6B,S100A2,LYZ,CD74,IGHG1,IGHA1,JCHAIN,CD74,AMTN'

Conversion to h5ad Format¶

Convert the n5 container back to the h5ad format for subsequent downstream analyses. This will also transfer the transformation models from the ST alignment onto the preprocessed and background-removed H&E images. This script will output the aligned spatial coordinates and an image volume that can be used for subsequent 3D visualization, of spatial transcriptomics and H&E staining in a common coordinate system.

openst from_3d_registration --args --metadata=<where_to_write_metadata>

You can quickly generate a HTML report to visualize the alignment quality. This will provide, for instance, a volumetric rendering on your browser using the channels (genes) selected for registration. This will also visualize the sections individually, to assess the deformations per section after registration, as well as the deformation fields.

openst report --metadata=<where_to_write_metadata> --output=<path_to_html_file>

With these steps completed, you will have successfully reconstructed a 3D representation of your biological samples, integrating spatial transcriptomics data and H&E images. This 3D reconstruction provides valuable insights into the spatial distribution of gene expression within your samples and enhances your understanding of complex biological structures.

3D visualization with ParaView¶

(explain)