Human Brain Spatially-Resolved Transcriptomics Leonardo Collado Torres, LIBD Investigator + Asst. Prof. Johns Hopkins Biostatistics Spatial Biology West Coast US 2024 December 5th 2024 Slides available at speakerdeck.com/lcolladotor
- A slide contains 4 capture areas, each full of thousands of 55um-wide “spots” (often containing 1-10 cells) - Unique barcodes in each spot bind to particular genes; after sequencing, gene expression can be tied back to exact spots, forming a spatial map Kristen R. Maynard 5
other tools) • DropletUtils::read10xVisium() → spatialLIBD::read10xVisiumWrapper() • Spot QC ◦ Drop high mitochondria % spots? ◦ Drop spots with low UMI counts? ▪ Biological vs technical reasons • Spot clustering (spatially-aware) and/or manual annotation • Choosing a spot clustering resolution ◦ Can be guided by spatially cluster registration
other tools) • DropletUtils::read10xVisium() → spatialLIBD::read10xVisiumWrapper() • Spot QC ◦ Drop high mitochondria % spots? ◦ Drop spots with low UMI counts?
other tools) • DropletUtils::read10xVisium() → spatialLIBD::read10xVisiumWrapper() • Spot QC ◦ Drop high mitochondria % spots? ◦ Drop spots with low UMI counts? ▪ Biological vs technical reasons
neighbors based on spatial coordinates ◦ Use neighborhood to calculate z-score for the QC metric (library size, detected genes, mito rate) ◦ Identity outlier spots based on z-score Fig 1: An overview of SpotSweeper SpotSweeper by Totty, Hicks, Guo 10.1101/2024.06.06.597765
low library size driven by barcode biases. • 6 barcodes in Visium slides have low library sizes across datasets • Synthetic barcodes at these spots may be responsible for downstream quality issues ◦ Certain k-mers show bias towards larger or smaller library sizes SpotSweeper by Totty, Hicks, Guo 10.1101/2024.06.06.597765
other tools) • DropletUtils::read10xVisium() → spatialLIBD::read10xVisiumWrapper() • Spot QC ◦ Drop high mitochondria % spots? ◦ Drop spots with low UMI counts? ▪ Biological vs technical reasons • Spot clustering (spatially-aware) and/or manual annotation • Choosing a spot clustering resolution ◦ Can be guided by spatially cluster registration
data • Immediately make them after running SpaceRanger • Update them as we generate more results • Share them with the publication of the results • spatial.libd.org/spatialLIBD/ • research.libd.org/spatialDLPFC/#interactive-websites • research.libd.org/Visium_SPG_AD/#interactive-websites • …
bins, not spots, at 3 different resolutions - 8μm bin size is recommended for analysis by 10x Genomics - Compare to 100μm distance between spots! - ~700k bins, compared to ~5k spots! - 2μm bin size is subcellular, and can be combined with segmentation to form cells “Bin level”: 8μm bins “Cell level”: Individual cells from combining 2μm bins 16μm bin border 8μm bin border 2μm bin border cell
aim to use the best methods 47 Moses, L., Pachter, L. Museum of spatial transcriptomics. Nat Methods 19, 534–546 (2022). https://doi.org/10.1038/s41592-022-01409-2
Run time (per sample) Required memory (per sample, GB) Integrates well with SpatialExperiment Operates on multiple samples simultaneously Uses GPU Documentation quality Authors responsive bin2cell Yes 30 min < 32 Yes No No Good Yes FICTURE Yes 3 hours < 64 No No No Okay Yes SEraster Yes 20 min < 64 Yes No No Good Yes MERINGUE Sort of 1 day > 400 Yes No No Okay Yes Giotto Yes Varied Varied Yes Yes No Needs improvement Banksy Yes 3 hours > 250 Yes Yes No Okay HERGAST Yes Okay ENACT @Nick-Eagles Nicholas J. Eagles #RStats and #PyStats https://github.com/LieberInstitute/jhpce_module_source
Weber @stephaniehicks Stephanie C Hicks @abspangler Abby Spangler @martinowk Keri Martinowich @CerceoPage Stephanie C Page @kr_maynard Kristen R Maynard @lcolladotor Leonardo Collado-Torres @Nick-Eagles Nicholas J Eagles Kelsey D Montgomery Sang Ho Kwon Image Analysis Expression Analysis Data Generation Thomas M Hyde @lahuuki Louise A Huuki-Myers @BoyiGuo Boyi Guo @mattntran Matthew N Tran @sowmyapartybun Sowmya Parthiban Slides available at speakerdeck.com /lcolladotor + Many more LIBD, JHU, and external collaborators @mgrantpeters Melissa Grant-Peters @prashanthi-ravichandran (GH) Prashanthi Ravichandran