In drisso/scRNAseq: Collection of Public Single-Cell RNA-Seq Datasets

library(BiocStyle)
knitr::opts_chunk$set(error=FALSE, message=FALSE, warning=FALSE)

Download the data

We obtain a single-cell RNA sequencing dataset of the human PBMCs from @mair2020targeted. Counts for endogenous genes and antibody-derived tags are available from the Gene Expression Omnibus using the accession number GSE13525. Of particular interest are the *Combined_PBMC_AbSeq*.csv.gz files that contain the data for Figure 3A.

library(BiocFileCache)
bfc <- BiocFileCache("raw_data", ask = FALSE)
base.url <- file.path("ftp://ftp.ncbi.nlm.nih.gov/geo/samples/",
    "GSM4005nnn/GSM4005486/suppl/")
Abseq_1 <- count.file <- bfcrpath(bfc, file.path(base.url,
    "GSM4005486_Combined_PBMC_AbSeq_1_DBEC_MolsPerCell_with_SampleTag.csv.gz"))

base.url <- file.path("ftp://ftp.ncbi.nlm.nih.gov/geo/samples/",
    "GSM4005nnn/GSM4005487/suppl/")
Abseq_2 <- count.file <- bfcrpath(bfc, file.path(base.url,
    "GSM4005487_Combined_PBMC_AbSeq_2_DBEC_MolsPerCell_with_SampleTag.csv.gz"))

Processing the data

We set up a function to process each of these files. This breaks up the data frame into the two matrices (RNA and ADT) as well as the sample-level metadata; it also harvests some row-level metadata from the feature names.

library(S4Vectors)
ingester <- function(fname) {
    df <- read.csv(fname, row.names = 1, check.names = FALSE)
    meta <- df[,tail(colnames(df), 2)]
    mat <- t(as.matrix(df[,head(colnames(df), -2)]))

    is.protein <- grepl("pAbO", rownames(mat))
    P <- mat[is.protein,]
    RNA <- mat[!is.protein,]

    rna.rowdata <- strsplit(rownames(RNA), "\\|")
    rna.rowdata <- DataFrame(do.call(rbind, rna.rowdata))
    colnames(rna.rowdata) <- c("Symbol", "RefSeq", "Type")
    rownames(RNA) <- with(rna.rowdata, paste0(Symbol, "_", ifelse(Type=="PolyA_1", Type, "RNA")))

    p.rowdata <- strsplit(rownames(P), "\\|")
    p.rowdata <- DataFrame(do.call(rbind, p.rowdata))[,1:3]
    colnames(p.rowdata) <- c("Symbol", "Alternative", "ID")
    rownames(P) <- with(p.rowdata, paste0(Symbol, "_", Alternative))

    list(rna.mat=RNA, rna.rowdata=rna.rowdata, 
        p.mat=P, p.rowdata=p.rowdata, 
        coldata=DataFrame(meta))
}

We run the ingester on each of the two files.

ingested1 <- ingester(Abseq_1)
dim(ingested1$rna.mat)
dim(ingested1$p.mat)
ingested1$coldata

ingested2 <- ingester(Abseq_2)
dim(ingested2$rna.mat)
dim(ingested2$p.mat)
ingested2$coldata

We check that the row metadata is consistent across both files.

stopifnot(identical(ingested1$rna.rowdata, ingested2$rna.rowdata))
stopifnot(identical(ingested1$p.rowdata, ingested2$p.rowdata))
stopifnot(identical(colnames(ingested1$coldata), colnames(ingested2$coldata)))
ingested1$p.rowdata
ingested1$rna.rowdata

We then combine all of the pieces of information into one matrix per set of features and a common sample metadata dataframe.

final.p.mat <- cbind(ingested1$p.mat, ingested2$p.mat)
dim(final.p.mat)

final.rna.mat <- cbind(ingested1$rna.mat, ingested2$rna.mat)
dim(final.rna.mat)

final.coldata <- rbind(ingested1$coldata, ingested2$coldata)
final.coldata$Cartridge <- rep(as.character(1:2), 
    c(nrow(ingested1$coldata), nrow(ingested2$coldata)))
final.coldata

stopifnot(identical(nrow(final.coldata), ncol(final.p.mat)))
stopifnot(identical(nrow(final.coldata), ncol(final.rna.mat)))

We also coerce all sample names to the same set of values to avoid later confusion.

final.names <- paste0(colnames(final.p.mat), "-", final.coldata$Cartridge)
rownames(final.coldata) <- colnames(final.p.mat) <- colnames(final.rna.mat) <- final.names
head(final.names)

Save for upload

We now save all of the relevant components to file for upload to r Biocpkg("ExperimentHub"). Note that it doesn't matter which row data we use, as they should be the same.

repath <- file.path("scRNAseq", "mair-pbmc", "2.4.0")
dir.create(repath, showWarnings=FALSE, recursive=TRUE)
saveRDS(final.coldata, file=file.path(repath, "coldata.rds"))

saveRDS(ingested1$rna.rowdata, file=file.path(repath, "rowdata-rna.rds"))
saveRDS(final.rna.mat, file=file.path(repath, "counts-rna.rds"))

saveRDS(ingested1$p.rowdata, file=file.path(repath, "rowdata-adt.rds"))
saveRDS(final.p.mat, file=file.path(repath, "counts-adt.rds"))