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edgeR, Pseudobulk scRNA-seq

Hello-- I am a bit familiar with the preface of pseudobulk differentiall expression analysis, however cannot find succinct tutorials for newbies concerning edgeR for scRNA-seq. I was wondering if anyone was familiar with a tutorial taking a Seurat scRNA-seq object all the way to edgeR analysis-- volcano plots and generating the list of DEGs?

Thank you in advance!

seurat scrna-seq edger

3 answers

See Section 4.10 of the edgeR User's Guide. The Case Study is titled "Single cell RNA-seq differential expression with pseudo-bulking" and it gives complete code for conducting an edgeR pseudo-bulk analysis starting from a Seurat scRNA-seq object, so it seems exactly what you're after:

https://bioconductor.org/packages/3.17/bioc/vignettes/edgeR/inst/doc/edgeRUsersGuide.pdf

Out of interest, would it conceptually be possible to support a sparse matrix such as CsparseMatrix (as commonly used in Seurat and SingleCellExperiment) in estimateDisp rather than expanding it to an ordinary matrix during DGEList creation?

The code in the above edgeR case study already fully supports Seurat sparse matrices. The case study converts the Seurat object directly to pseudo-bulk counts without ever expanding the single-cell data to a full matrix. estimateDisp() is only run on the pseudo-bulk counts.

Note that the case study requires edgeR for Bioconductor 3.17, which will be the official Bioconductor version in a week or two.

OSCA has a great section on this, although it's geared towards the scran/bioconductor universe of scRNA-seq analysis tools.

This is a very good resource single-cell best practices. I find this tutorial provided by in the decoupler package (python) to be good as well.

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