Quick Start Guide for SigBridgeR

if (!requireNamespace("remotes")) {
  install.packages("remotes")
}
remotes::install_github("WangLabCSU/SigBridgeR")


# # Or install from r-universe:
# install.packages("SigBridgeR", repos = "https://wanglabcsu.r-universe.dev")

library(SigBridgeR)
library(Seurat)

We will start with a simple example.

if (requireNamespace("here", quietly = TRUE)) {
  setwd(here::here())
  knitr::opts_knit$set(root.dir = here::here())
}

library(zeallot) # %<-%
c(mat_exam, bulk_bi, pheno_bi) %<-% LoadRefData(data_type = "binary")

mat_exam is a single-cell RNA expression matrix, bulk_bi is a bulk tissue RNA expression matrix, and pheno_bi is the phenotypic data associated with bulk_bi. When using a binary or continuous phenotype, the reference data is a named vector.

head(pheno_bi)
# TCGA-CA-5256-01 TCGA-AZ-6599-01 TCGA-AA-3655-01 TCGA-A6-6137-01 TCGA-CK-4952-01 TCGA-A6-5657-01
#               1               1               1               1               1               1

By the way, when usinng a survival phenotype, the reference data is a data.frame.

pheno_sur <- LoadRefData(data_type = "survival")[[3]]
head(pheno_sur)
#               time status
# TCGA-69-7978  4.40      0
# TCGA-62-8399 88.57      0
# TCGA-78-7539 25.99      0
# TCGA-73-4658 52.56      1
# TCGA-44-6775 23.16      0
# TCGA-44-2655 43.50      0

The single-cell RNA expression matrix needs to be processed into a Seurat object. We set scale_features to all genes in order to maximize the flexibility of downstream analyses and capture a broader range of biological signals, so as to avoid insignificant results caused by too small a dataset.

seurat_obj <- SCPreProcess(
  mat_exam,
  quality_control.pattern = "^MT-",
  scale_features = rownames(mat_exam),
  dims = 1:20
)

Then we can use these data to screen out phenotype-assoicated cells. Let’s start by trying Scissor.

scissor_res <- Screen(
  bulk_bi,
  seurat_obj,
  pheno_bi,
  phenotype_class = "binary",
  screen_method = "Scissor",
  scissor_alpha = 0.05
)

Other screening methods are also available.

scpas_res <- Screen(
  bulk_bi,
  seurat_obj,
  pheno_bi,
  phenotype_class = "binary",
  screen_method = "scPAS",
  alpha = 0.05
)

Since the screening is performed on the same data, we merge them.

merged_seurat <- MergeResult(
  scissor_res,
  scpas_res
)

Finally, we visualize the screening results.

stacked bar plot:

fraction = ScreenFractionPlot(
  merged_seurat,
  group_by = "seurat_clusters",
  screen_type = c("scissor", "scPAS")
)

knitr::include_graphics("vignettes/example_figures/fraction_q.png")

$fraction_q$

Venn diagram:

c(scissor_pos, scpas_pos) %<-%
  purrr::map(
    c("scissor", "scPAS"),
    ~ colnames(merged_seurat)[
      which(merged_seurat[[.x]] == "Positive")
    ]
  )

all_cells <- colnames(seurat_obj)

pos_venn = list(
  scissor = scissor_pos,
  scpas = scpas_pos,
  all_cells = all_cells
)

set.seed(123)

venn_plot = ggVennDiagram::ggVennDiagram(
  x = pos_venn,
  # * the labels of each group to be shown on the diagram
  category.names = c(
    "Scissor",
    "scPAS",
    "All cells"
  ),
  # * the colors of each group
  set_color = c(
    "#a33333ff",
    "#37ae00ff",
    "#008383ff"
  )
) +
  ggplot2::scale_fill_gradient(low = "white", high = "#ffb6b6ff") +
  ggplot2::ggtitle("Screening Venn Diagram")

knitr::include_graphics("vignettes/example_figures/venn_q.png")

Set plot:

upset <- ScreenUpset(
  merged_seurat,
  screen_type = c("scissor", "scPAS")
)

knitr::include_graphics("vignettes/example_figures/upset_q.png")

2D UMAP:

library(patchwork)
library(randomcoloR)

c(
  scissor_umap,
  scpas_umap
) %<-%
  purrr::map(
    c("scissor", "scPAS"),
    ~ Seurat::DimPlot(
      merged_seurat,
      group.by = .x,
      pt.size = 0.1,
      reduction = "umap",
      cols = c(
        "Neutral" = "#CECECE",
        "Positive" = "#ff3333",
        "Negative" = "#386c9b"
      )
    ) +
      ggplot2::ggtitle(.x)
  )

set.seed(123)
cols = randomcoloR::distinctColorPalette(
  length(unique(merged_seurat$seurat_clusters)),
  runTsne = TRUE
)

cluster_umap <- Seurat::DimPlot(
  merged_seurat,
  group.by = "seurat_clusters",
  pt.size = 0.1,
  reduction = "umap",
  cols = cols
) +
  ggplot2::ggtitle("seurat_clusters")


# * Show
umaps = cluster_umap +
  scissor_umap +
  scpas_umap +
  plot_layout(ncol = 2)

umaps

knitr::include_graphics("vignettes/example_figures/umaps_q.png")

Quick Start Guide for SigBridgeR

2025-09-23

Quick Start Guide for SigBridgeR