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cellNexus

Mangiola et al.

Lifecycle:maturing

Introduction

cellNexus extends the functionality of CuratedAtlasQueryR by providing a unified interface for querying and accessing the harmonised, curated, and reannotated CELLxGENE human cell atlas. It enables reproducible, programmatic exploration of large-scale single-cell datasets, supporting data retrieval at the cell, sample, and dataset levels with flexible filtering based on tissue, cell type, experimental condition, and other metadata. Retrieved data are returned in formats ready for downstream analysis.

The package integrates over 44 million human cells processed through a standardised pipeline, including consistent quality control, normalisation, and unified abundance representations (e.g., single-cell, counts-per-million, normalised expression, and pseudobulk). This harmonisation facilitates efficient cross-dataset comparison and integration.

Data are hosted on the ARDC Nectar Research Cloud, and most functions access them via web requests; therefore, an active network connection is required for typical use.

While both cellNexus and CuratedAtlasQueryR rely on precomputed expression layers, cellNexus adopts a more standardised and transparent processing workflow. This includes explicit removal of empty droplets and dead cells, followed by harmonised quality control, normalisation, and multi-layer data generation, ensuring alignment with evolving CELLxGENE releases.

Repositories

R API: here

Python API: here

Article code: here

Query interface

Installation

devtools::install_github("MangiolaLaboratory/cellNexus")

Load the package

library(cellNexus)

Load additional packages

suppressPackageStartupMessages({
  library(ggplot2)
})

Load and explore the metadata

Load the metadata

By default, get_metadata() loads harmonised annotations. Metadata is saved to get_default_cache_dir() unless a custom path is provided via the cache_directory argument. The metadata variable can then be re-used for all subsequent queries.

The unified pseudobulk AnnData object was pre-generated outside of this vignette applying quality control and retaining at least 15,000 intersecting genes across samples and hosted on Zenodo to avoid lengthy recompilation. Download the latest version: pseudobulk_se.h5ad. For all versions: 10.5281/zenodo.22668580.

The following sections demonstrate the metadata, quality control, generation of raw and normalised counts, and pseudobulk construction for the specified query.

metadata <- get_metadata()
metadata
#> # Source:   SQL [?? x 33]
#> # Database: DuckDB 1.4.3 [unknown@Linux 5.14.0-570.123.1.el9_6.x86_64:R 4.5.3/:memory:]
#>    cell_id observation_joinid dataset_id        sample_id donor_id feature_count age_days nFeature_expressed_i…¹ nCount_RNA
#>      <dbl> <chr>              <chr>             <chr>     <chr>            <int>    <int>                  <int>      <dbl>
#>  1    7951 V^DVv&wmix         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                    670      9708.
#>  2     430 bE&g|Ty{lq         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                    576      8940.
#>  3   10537 +P10$OJbtq         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                   1846      9878.
#>  4    4681 `rtxaAa~)4         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                    642      9520.
#>  5   10538 YTZT;WA*H1         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                   1206      9817.
#>  6   11685 q6&?h```1s         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                   1378      9663.
#>  7   10539 {Ij`DT8SD?         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                    929      9834.
#>  8    4682 s1e`j)^y54         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                   2611      9527.
#>  9    4683 0G5XsAaJ&m         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                    517      9318.
#> 10   10540 GPsK`oVmW=         ca46ffe6-0a26-4d… 86fbf754… Hs254            28675    14965                   1218      9649.
#> # ℹ more rows
#> # ℹ abbreviated name: ¹​nFeature_expressed_in_sample
#> # ℹ 24 more variables: empty_droplet <lgl>, cell_type_unified_ensemble <chr>, is_immune <lgl>, subsets_Mito_percent <int>,
#> #   subsets_Ribo_percent <int>, high_mitochondrion <lgl>, high_ribosome <lgl>, alive <lgl>, scDblFinder.class <chr>,
#> #   file_id_cellNexus_single_cell <chr>, file_id_cellNexus_pseudobulk <chr>, count_upper_bound <dbl>,
#> #   nfeature_expressed_threshold <dbl>, inversed_inferred_distribution <chr>, inferred_distribution <chr>,
#> #   cell_annotation_blueprint_singler <chr>, cell_annotation_monaco_singler <chr>, cell_annotation_azimuth_l2 <chr>, …

Quality control

cellNexus metadata applies standardised quality control to filter out empty droplets, dead or damaged cells, doublets, and samples with low gene counts.

metadata <- metadata |>
  keep_quality_cells()

Join Census metadata

Original Census annotations can be retrieved by the function get_census_metadata(), and registered to lazy tibble format by DuckDB

census_metadata <- cellNexus:::get_census_metadata("2024-07-01")
#> ℹ Opening Census version 2024-07-01.
#> ℹ Reading Census obs table.

con <- dbplyr::remote_con(metadata)

duckdb::duckdb_register_arrow(con, "census_metadata", census_metadata)

metadata <- metadata |>
  dplyr::left_join(tbl(con, "census_metadata") |> 
                   dplyr::select(observation_joinid, dataset_id, tissue,
                                 self_reported_ethnicity, cell_type, assay,
                                 disease, sex))
#> Joining with `by = join_by(observation_joinid, dataset_id)`

Explore tissues

metadata |>
  dplyr::distinct(tissue, cell_type_unified_ensemble)
#> # Source:   SQL [?? x 2]
#> # Database: DuckDB 1.4.3 [unknown@Linux 5.14.0-570.123.1.el9_6.x86_64:R 4.5.3/:memory:]
#>    tissue                  cell_type_unified_ensemble
#>    <chr>                   <chr>                     
#>  1 sigmoid colon           b memory                  
#>  2 sigmoid colon           cdc                       
#>  3 mesenteric lymph node   t cd4                     
#>  4 mesenteric lymph node   b                         
#>  5 upper lobe of left lung pdc                       
#>  6 upper lobe of left lung progenitor                
#>  7 upper lobe of left lung Unknown                   
#>  8 upper lobe of left lung treg                      
#>  9 upper lobe of left lung b naive                   
#> 10 ascending colon         cd4 tcm                   
#> # ℹ more rows

Download single-cell RNA sequencing counts

Query raw counts

single_cell_counts <-
  metadata |>
  dplyr::filter(
    self_reported_ethnicity == "African American" &
      assay == "10x 3' v3" &
      tissue == "breast" &
      cell_type == "T cell"
  ) |>
  get_single_cell_experiment()
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> For native R and reading and writing of H5AD files, an R <AnnData> object, and conversion to <SingleCellExperiment> or
#> <Seurat> objects, check out the anndataR package:
#> ℹ Install it from Bioconductor with `BiocManager::install("anndataR")`
#> ℹ See more at <https://bioconductor.org/packages/anndataR/>
#> 
Reading counts ■■■■                              10% | ETA:  9s
#> 
Reading counts ■■■■■■■                           20% | ETA:  7s
#> 
Reading counts ■■■■■■■■■■                        30% | ETA:  6s
#> 
Reading counts ■■■■■■■■■■■■■                     40% | ETA:  4s
#> 
Reading counts ■■■■■■■■■■■■■■■■                  50% | ETA:  4s
#> 
Reading counts ■■■■■■■■■■■■■■■■■■■               60% | ETA:  3s
#> 
Reading counts ■■■■■■■■■■■■■■■■■■■■■■            70% | ETA:  2s
#> 
Reading counts ■■■■■■■■■■■■■■■■■■■■■■■■■         80% | ETA:  1s
#> 
Reading counts ■■■■■■■■■■■■■■■■■■■■■■■■■■■■      90% | ETA:  1s
#> 
                                                                
#> ℹ Compiling Experiment.
#> 
#> This message is displayed once per session.

single_cell_counts
#> class: SingleCellExperiment 
#> dim: 33145 2794 
#> metadata(0):
#> assays(1): counts
#> rownames(33145): ENSG00000243485 ENSG00000237613 ... ENSG00000277475 ENSG00000268674
#> rowData names(0):
#> colnames(2794): 73_1 74_1 ... 6_10 7_10
#> colData names(39): observation_joinid dataset_id ... sex original_cell_
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

Query counts scaled per million

single_cell_cpm <-
  metadata |>
  dplyr::filter(
    self_reported_ethnicity == "African American" &
      assay == "10x 3' v3" &
      tissue == "breast" &
      cell_type == "T cell"
  ) |>
  get_single_cell_experiment(assays = "cpm")
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> 
Reading cpm ■■■■■■■                           20% | ETA:  5s

Reading cpm ■■■■■■■■■■                        30% | ETA:  4s

Reading cpm ■■■■■■■■■■■■■                     40% | ETA:  4s

Reading cpm ■■■■■■■■■■■■■■■■                  50% | ETA:  3s

Reading cpm ■■■■■■■■■■■■■■■■■■■               60% | ETA:  3s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■            70% | ETA:  2s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■■■■         80% | ETA:  1s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■■■■■■■      90% | ETA:  1sCompiling Experiment.

single_cell_cpm
#> class: SingleCellExperiment 
#> dim: 33145 2794 
#> metadata(0):
#> assays(1): cpm
#> rownames(33145): ENSG00000243485 ENSG00000237613 ... ENSG00000277475 ENSG00000268674
#> rowData names(0):
#> colnames(2794): 1_1 80_1 ... 9_10 10_10
#> colData names(39): observation_joinid dataset_id ... sex original_cell_
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

Query SCT normalised counts

single_cell_sct <-
  metadata |>
  dplyr::filter(
    self_reported_ethnicity == "African American" &
      assay == "10x 3' v3" &
      tissue == "breast" &
      cell_type == "T cell"
  ) |>
  get_single_cell_experiment(assays = "sct")
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> 
Reading sct ■■■■■■■                           20% | ETA:  5s

Reading sct ■■■■■■■■■■                        30% | ETA:  4s

Reading sct ■■■■■■■■■■■■■                     40% | ETA:  4s

                                                             
! The number of cells in the SingleCellExperiment will be less than the number of cells you have selected from the metadata. Are cell IDs duplicated? Or, do cell IDs correspond to the counts file?
#> Reading sct ■■■■■■■■■■■■■                     40% | ETA:  4s

Reading sct ■■■■■■■■■■■■■■■■                  50% | ETA:  3s

                                                             
! The number of cells in the SingleCellExperiment will be less than the number of cells you have selected from the metadata. Are cell IDs duplicated? Or, do cell IDs correspond to the counts file?
#> Reading sct ■■■■■■■■■■■■■■■■                  50% | ETA:  3s

Reading sct ■■■■■■■■■■■■■■■■■■■               60% | ETA:  3s

Reading sct ■■■■■■■■■■■■■■■■■■■■■■            70% | ETA:  2s

Reading sct ■■■■■■■■■■■■■■■■■■■■■■■■■         80% | ETA:  1s

Reading sct ■■■■■■■■■■■■■■■■■■■■■■■■■■■■      90% | ETA:  1s

                                                             
! cellNexus says: 1601 cell(s) from your metadata are absent from the SCT assay across 2 file(s). This is expected: SCT normalisation is run per sample and may fail for samples with very few cells or extreme count distributions. The returned object contains only cells from samples where SCT succeeded. Affected sample_id(s): 765554078ca8d1eaf2712000c0df0d6f, 8940e0767e7eca1b72d37b4138be2276, a79912cb9aaa8d8c0b1a3cdcc9294f8c.
#> ℹ Compiling Experiment.

single_cell_sct
#> class: SingleCellExperiment 
#> dim: 33145 1193 
#> metadata(0):
#> assays(1): sct
#> rownames(33145): ENSG00000243485 ENSG00000237613 ... ENSG00000277475 ENSG00000268674
#> rowData names(0):
#> colnames(1193): 80_1 81_1 ... 6_10 7_10
#> colData names(39): observation_joinid dataset_id ... sex original_cell_
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

Query pseudobulk

pseudobulk_counts <-
  metadata |>
  dplyr::filter(
    assay == "10x 5' v1" &
      tissue == "lung" &
      cell_type == "classical monocyte"
  ) |>
  get_pseudobulk()
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> 
Reading counts ■■■■■                             14% | ETA:  9s

Reading counts ■■■■■■■■■■                        29% | ETA:  9s

Reading counts ■■■■■■■■■■■■■■                    43% | ETA:  8s

Reading counts ■■■■■■■■■■■■■■■■■■                57% | ETA:  6s

Reading counts ■■■■■■■■■■■■■■■■■■■■■■            71% | ETA:  4s

Reading counts ■■■■■■■■■■■■■■■■■■■■■■■■■■■       86% | ETA:  2s

                                                                
! cellNexus says: Not all genes completely overlap across the provided objects. Counts are generated by genes intersection.
#> ℹ Compiling Experiment.

pseudobulk_counts
#> class: SingleCellExperiment 
#> dim: 15888 146 
#> metadata(0):
#> assays(1): counts
#> rownames(15888): ENSG00000177757 ENSG00000225880 ... ENSG00000160307 ENSG00000160310
#> rowData names(0):
#> colnames(146): 2e8c9911c9bfbffc07288adef93d3cf2___cd14 mono 0d874636bc714a8d0146dfa0cbacadc5___cd14 mono ...
#>   1c7e90df93b48acabb013c8202830df5___cd14 mono 1c7e90df93b48acabb013c8202830df5___monocytic
#> colData names(31): sample_id cell_type_unified_ensemble ... sex sample_identifier
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

Download cell communication metadata

Cell communication metadata was generated based on post-QC cells per sample using CellChat v2 method. It uses our harmonised cell type annotation (cell_type_unified_ensemble) to infer the communication. It captures inferred communication at both the ligand–receptor pair level and the signalling pathway level.

  • interaction_count: The number of inferred interactions between each pair of cell groups.

  • interaction_weight: The aggregated communication strength between each pair of cell groups.

For definitions of additional annotations, please refer to the CellChat v2 documentation: https://github.com/jinworks/CellChat.

For demonstration purpose, read cell communication metadata from a demo file here. Users do not need to specify cloud_metadata argument in this case.

get_cell_communication_strength(cloud_metadata = get_metadata_url("cellNexus_lr_signaling_pathway_strength_DEMO.parquet"))
#> # Source:   SQL [?? x 16]
#> # Database: DuckDB 1.4.3 [unknown@Linux 5.14.0-570.123.1.el9_6.x86_64:R 4.5.3/:memory:]
#>   source    target ligand receptor   lr_prob lr_pval interaction_name   interaction_name_2 pathway_name annotation evidence
#>   <chr>     <chr>  <chr>  <chr>        <dbl>   <dbl> <chr>              <chr>              <chr>        <chr>      <chr>   
#> 1 b         b      TGFB1  TGFbR1_R2 0.000116    1    TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> 2 b memory  b      TGFB1  TGFbR1_R2 0.000865    1    TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> 3 b naive   b      TGFB1  TGFbR1_R2 0.000696    0.99 TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> 4 cd14 mono b      TGFB1  TGFbR1_R2 0.00240     0.81 TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> 5 cd4 naive b      TGFB1  TGFbR1_R2 0.000957    1    TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> 6 cd4 tem   b      TGFB1  TGFbR1_R2 0.00242     0.76 TGFB1_TGFBR1_TGFB… TGFB1 - (TGFBR1+T… TGFb         Secreted … KEGG: h…
#> # ℹ 5 more variables: pathway_prob <dbl>, pathway_pval <dbl>, sample_id <chr>, interaction_count <dbl>,
#> #   interaction_weight <dbl>

Extract only a subset of genes

This is helpful if just few genes are of interest (e.g ENSG00000134644 (PUM1)), as they can be compared across samples. cellNexus uses ENSEMBL gene ID(s).

single_cell_cpm <-
  metadata |>
  dplyr::filter(
    self_reported_ethnicity == "African American" &
      assay == "10x 3' v3" &
      tissue == "breast" &
      cell_type == "T cell"
  ) |>
  get_single_cell_experiment(assays = "cpm", features = "ENSG00000134644")
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> 
Reading cpm ■■■■■■■                           20% | ETA:  9s

Reading cpm ■■■■■■■■■■                        30% | ETA:  7s

Reading cpm ■■■■■■■■■■■■■                     40% | ETA:  5s

Reading cpm ■■■■■■■■■■■■■■■■                  50% | ETA:  4s

Reading cpm ■■■■■■■■■■■■■■■■■■■               60% | ETA:  3s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■            70% | ETA:  2s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■■■■         80% | ETA:  2s

Reading cpm ■■■■■■■■■■■■■■■■■■■■■■■■■■■■      90% | ETA:  1sCompiling Experiment.

single_cell_cpm
#> class: SingleCellExperiment 
#> dim: 1 2794 
#> metadata(0):
#> assays(1): cpm
#> rownames(1): ENSG00000134644
#> rowData names(0):
#> colnames(2794): 76_1 77_1 ... 7_10 12_10
#> colData names(39): observation_joinid dataset_id ... sex original_cell_
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

Extract the counts as a Seurat object

This convert the H5 SingleCellExperiment to Seurat so it might take long time and occupy a lot of memory depending on how many cells you are requesting.

seurat_counts <-
  metadata |>
  dplyr::filter(
    self_reported_ethnicity == "African American" &
      assay == "10x 3' v3" &
      tissue == "breast" &
      cell_type == "T cell"
  ) |>
  get_seurat()
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> 
Reading counts ■■■■■■■                           20% | ETA:  5s

Reading counts ■■■■■■■■■■                        30% | ETA:  4s

Reading counts ■■■■■■■■■■■■■                     40% | ETA:  4s

Reading counts ■■■■■■■■■■■■■■■■                  50% | ETA:  3s

Reading counts ■■■■■■■■■■■■■■■■■■■               60% | ETA:  2s

Reading counts ■■■■■■■■■■■■■■■■■■■■■■            70% | ETA:  2s

Reading counts ■■■■■■■■■■■■■■■■■■■■■■■■■         80% | ETA:  1s

Reading counts ■■■■■■■■■■■■■■■■■■■■■■■■■■■■      90% | ETA:  1sCompiling Experiment.

seurat_counts
#> An object of class Seurat 
#> 33145 features across 2794 samples within 1 assay 
#> Active assay: counts (33145 features, 0 variable features)
#>  2 layers present: counts, data

By default, data is downloaded to get_default_cache_dir() output. If memory is a concern, users can specify a custom path to metadata and counts cache_directory argument. For example, get_metadata(cache_directory = "your_own_path") and get_single_cell_experiment(cache_directory = "your_own_path").

Same strategy can be applied for functions get_pseuodbulk() and get_seurat().

Save your SingleCellExperiment

The returned SingleCellExperiment can be saved with three modalities, as .rds or as HDF5 or as H5AD.

Saving as RDS (fast saving, slow reading)

Saving as .rds has the advantage of being fast, and the .rds file occupies very little disk space as it only stores the links to the files in your cache.

However it has the disadvantage that for big SingleCellExperiment objects, which merge a lot of HDF5 from your get_single_cell_experiment, the display and manipulation is going to be slow. In addition, an .rds saved in this way is not portable: you will not be able to share it with other users.

single_cell_counts |>
  saveRDS("single_cell_counts.rds")

Saving as HDF5 (slow saving, fast reading)

Saving as .hdf5 executes any computation on the SingleCellExperiment and writes it to disk as a monolithic HDF5. Once this is done, operations on the SingleCellExperiment will be comparatively very fast. The resulting .hdf5 file will also be totally portable and sharable.

However this .hdf5 has the disadvantage of being larger than the corresponding .rds as it includes a copy of the count information, and the saving process is going to be slow for large objects.

# ! IMPORTANT if you save 200K+ cells
HDF5Array::setAutoBlockSize(size = 1e+09)

single_cell_counts |>
  HDF5Array::saveHDF5SummarizedExperiment(
    "single_cell_counts",
    replace = TRUE,
    as.sparse = TRUE,
    verbose = TRUE
  )

Saving as H5AD (slow saving, fast reading)

Saving as .h5ad executes any computation on the SingleCellExperiment and writes it to disk as a monolithic H5AD. The H5AD format is the HDF5 disk representation of the AnnData object and is well-supported in Python.

However this .h5ad saving strategy has a bottleneck of handling columns with only NA values of a SingleCellExperiment metadata.

single_cell_counts |>
  anndataR::write_h5ad("single_cell_counts.h5ad",
    compression = "gzip",
    verbose = TRUE
  )

Visualise gene transcription

We can gather all CD14 monocytes cells and plot the distribution of ENSG00000085265 (FCN1) across all tissues

# Plots with styling
counts <- metadata |>

  # Filter and subset
  dplyr::filter(cell_type_unified_ensemble == "cd14 mono") |>

  # Get counts per million for FCN1 gene
  get_single_cell_experiment(assays = "cpm", features = "ENSG00000085265") |>
  suppressMessages() |>

  # Add feature to table
  tidySingleCellExperiment::join_features("ENSG00000085265", shape = "wide") |>

  # Rank x axis
  tibble::as_tibble() |>

  # Rename to gene symbol
  dplyr::rename(FCN1 = ENSG00000085265)

# Plot by disease
counts |>
  dplyr::with_groups(disease, ~ .x |>
    dplyr::mutate(median_count = median(`FCN1`, rm.na = TRUE))) |>

  # Plot
  ggplot(aes(forcats::fct_reorder(disease, median_count, .desc = TRUE), `FCN1`, color = dataset_id)) +
  geom_jitter(shape = ".") +

  # Style
  guides(color = "none") +
  scale_y_log10() +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 60, vjust = 1, hjust = 1)) +
  xlab("Disease") +
  ggtitle("FCN1 in CD14 monocytes by disease. Coloured by datasets")
#> Warning in scale_y_log10(): log-10 transformation introduced infinite values.

plot of chunk plot-fcn1-disease

plot of chunk plot-fcn1-disease
# Plot by tissue
counts |>
  dplyr::with_groups(tissue, ~ .x |>
    dplyr::mutate(median_count = median(`FCN1`, rm.na = TRUE))) |>

  # Plot
  ggplot(aes(
    forcats::fct_reorder(tissue,
      median_count,
      .desc = TRUE
    ),
    `FCN1`,
    color = dataset_id
  )) +
  geom_jitter(shape = ".") +

  # Style
  guides(color = "none") +
  scale_y_log10() +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 60, vjust = 1, hjust = 1)) +
  xlab("Tissue") +
  ggtitle("FCN1 in CD14 monocytes by tissue. Colored by datasets") +
  theme(legend.position = "none", axis.text.x = element_text(size = 6.5))
#> Warning in scale_y_log10(): log-10 transformation introduced infinite values.

plot of chunk plot-fcn1-tissue

plot of chunk plot-fcn1-tissue

Integrate cloud and local metadata

cellNexus not only enables users to query our metadata but also allows integration with your local metadata. Additionally, users can integrate with your metadata stored in the cloud.

To enable this feature, users must include file_id_cellNexus_single_cell and atlas_id (e.g cellxgene/dd-mm-yy) columns in the metadata. See metadata structure in cellNexus::pbmc3k_sce

# Set up local cache and paths
local_cache <- tempdir()
layer <- "counts"
meta_path <- file.path(local_cache, "pbmc3k_metadata.parquet")
data(pbmc3k_sce)

# Extract and prepare metadata
pbmc3k_metadata <- pbmc3k_sce |>
  S4Vectors::metadata() |>
  purrr::pluck("data") |>
  dplyr::mutate(
    counts_directory = file.path(tempdir(), atlas_id, layer),
    sce_path = file.path(counts_directory, file_id_cellNexus_single_cell)
  )

# Get unique paths
counts_directory <- pbmc3k_metadata |>
  dplyr::pull(counts_directory) |>
  unique()

sce_path <- pbmc3k_metadata |>
  dplyr::pull(sce_path) |>
  unique()

# Create directory structure
dir.create(counts_directory, recursive = TRUE, showWarnings = FALSE)

# Save data to disk
pbmc3k_sce |>
  S4Vectors::metadata() |>
  purrr::pluck("data") |>
  arrow::write_parquet(meta_path)

# Save SCE object
pbmc3k_sce |>
  anndataR::write_h5ad(sce_path, compression = "gzip", mode = "w")
# A cellNexus file
file_id_from_cloud <- "e52795dec7b626b6276b867d55328d9f___1.h5ad"
file_id_local <- basename(sce_path)

get_metadata(
  cloud_metadata = cellNexus::SAMPLE_DATABASE_URL,
  local_metadata = meta_path,
  cache_directory = local_cache
) |>
  # For illustration purpose, only filter a selected cloud metadata and the saved metadata
  dplyr::filter(file_id_cellNexus_single_cell %in% c(file_id_from_cloud, file_id_local)) |>
  dplyr::select(cell_id, sample_id, dataset_id, cell_type_unified_ensemble, atlas_id, file_id_cellNexus_single_cell) |>
  get_single_cell_experiment(cache_directory = local_cache)
#> ℹ Downloading 1 file, totalling 0 GB
#> ℹ Downloading https://object-store.rc.nectar.org.au/v1/AUTH_06d6e008e3e642da99d806ba3ea629c5/cellNexus-metadata/sample_hca2024_v2.4.0.parquet to /vast/scratch/users/shen.m/tmp/RtmpUOaoJG/sample_hca2024_v2.4.0.parquet
#> ℹ Realising metadata.
#> ℹ Synchronising files
#> ℹ Reading files.
#> ℹ Compiling Experiment.
#> # A SingleCellExperiment-tibble abstraction: 500 × 7
#> # �[90mFeatures=13132 | Cells=500 | Assays=counts�[0m
#>    .cell            sample_id dataset_id cell_type_unified_ensemble atlas_id          file_id_cellNexus_si…¹ original_cell_
#>    <chr>            <chr>     <chr>      <chr>                      <chr>             <chr>                  <chr>         
#>  1 AAACATACAACCAC_1 pbmc3k    pbmc3k     Memory CD4 T               cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACATACAACCAC
#>  2 AAACATTGAGCTAC_1 pbmc3k    pbmc3k     B                          cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACATTGAGCTAC
#>  3 AAACATTGATCAGC_1 pbmc3k    pbmc3k     Memory CD4 T               cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACATTGATCAGC
#>  4 AAACCGTGCTTCCG_1 pbmc3k    pbmc3k     CD14+ Mono                 cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACCGTGCTTCCG
#>  5 AAACCGTGTATGCG_1 pbmc3k    pbmc3k     NK                         cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACCGTGTATGCG
#>  6 AAACGCACTGGTAC_1 pbmc3k    pbmc3k     Memory CD4 T               cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACGCACTGGTAC
#>  7 AAACGCTGACCAGT_1 pbmc3k    pbmc3k     CD8 T                      cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACGCTGACCAGT
#>  8 AAACGCTGGTTCTT_1 pbmc3k    pbmc3k     CD8 T                      cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACGCTGGTTCTT
#>  9 AAACGCTGTAGCCA_1 pbmc3k    pbmc3k     Naive CD4 T                cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACGCTGTAGCCA
#> 10 AAACGCTGTTTCTG_1 pbmc3k    pbmc3k     FCGR3A+ Mono               cellxgene/03-10-… 67e196a3c4e145151fc9e… AAACGCTGTTTCTG
#> # ℹ 490 more rows
#> # ℹ abbreviated name: ¹​file_id_cellNexus_single_cell

Cell metadata

The complete metadata dictionary for the harmonised fields is available on the documentation site: cellNexus documentation.

Annotational annotations

Optionally, you can explore CELLxGENE metadata to retrieve additional information, such as the CELLxGENE URL (explorer_url), published paper title (title), published date (published at), and other dataset-level, file-level, or collection-level annotations.

This information can be joined with cellNexus metadata when needed. Note that these additional annotations are not used to produce this vignette.

For example, to explore CELLxGENE dataset-level annotations.

cellNexus:::get_cellxgene_metadata("dataset") |>
  dplyr::select(dplyr::where(~ !is.list(.x)))
#> # A tibble: 2,100 × 17
#>    dataset_id             dataset_version_id collection_id cell_count citation default_embedding explorer_url feature_count
#>    <chr>                  <chr>              <chr>              <int> <chr>    <chr>             <chr>                <int>
#>  1 6cda3b13-7257-45b9-ac… 9349c6fb-758d-483… db468083-041…      59605 Publica… X_tsne            https://cel…         32383
#>  2 42b6a476-c51d-4f8b-b6… a4a32eaa-9828-417… db468083-041…      11243 Publica… X_tsne            https://cel…         32383
#>  3 ebc2e1ff-c8f9-466a-ac… 687c09ff-731a-4e3… 8f126edf-540…     836148 Publica… <NA>              https://cel…         36306
#>  4 60a29d0b-1a37-4447-ac… b6da1a8e-2d81-42e… 4cbb929b-b03…      97125 Publica… X_umap            https://cel…         36030
#>  5 09b518f9-da64-44cc-ae… a14c154d-b867-486… 4cbb929b-b03…      37717 Publica… X_umap_Spectral_… https://cel…         35475
#>  6 3de0ad6d-4378-4f62-b3… b1ba366b-d63b-4fd… 625f6bf4-2f3…      46500 Publica… <NA>              https://cel…         25799
#>  7 30cd5311-6c09-46c9-94… 73024e1c-c5e4-48d… ed9185e3-5b8…     125117 Publica… <NA>              https://cel…         30000
#>  8 21d3e683-80a4-4d9b-bc… e6ef9f09-bf7f-49b… ed9185e3-5b8…     246964 Publica… <NA>              https://cel…         30000
#>  9 3f32121d-126b-4e8d-9f… cece25a7-9d37-475… 7651ac1a-f94…      36359 Publica… X_umap            https://cel…         32383
#> 10 3a8aec06-3309-4d37-b7… 281bf7bb-c74a-4da… c2879de0-aff…      26499 Dataset… <NA>              https://cel…         27986
#> # ℹ 2,090 more rows
#> # ℹ 9 more variables: mean_genes_per_cell <dbl>, primary_cell_count <int>, raw_data_location <chr>, schema_version <chr>,
#> #   title <chr>, tombstone <lgl>, x_approximate_distribution <chr>, published_at <date>, revised_at <date>

RNA abundance

The counts assay represents RNA abundance on the positive real scale, without non-linear transformations (e.g., log or square root). In the original CELLxGENE data, values were provided using a mix of scales and transformations. The method required to invert these transformations is recorded in inverse_transform column.

The cpm assay includes counts per million.

The sct assay includes normalised counts by sctranform.

Other representations

The rank assay is the representation of each cell’s gene expression profile where genes are ranked by expression intensity using singscore.

The pseudobulk assay includes aggregated RNA abundance for sample and cell type combination.

The detailed documentation for RNA abundance is available on the documentation site: cellNexus documentation.

Session Info

sessionInfo()
#> R version 4.5.3 (2026-03-11)
#> Platform: x86_64-pc-linux-gnu
#> Running under: Red Hat Enterprise Linux 9.6 (Plow)
#> 
#> Matrix products: default
#> BLAS:   /stornext/System/data/software/rhel/9/base/tools/R/4.5.3/lib64/R/lib/libRblas.so 
#> LAPACK: /stornext/System/data/software/rhel/9/base/tools/R/4.5.3/lib64/R/lib/libRlapack.so;  LAPACK version 3.12.1
#> 
#> locale:
#>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
#>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                 
#>  [9] LC_ADDRESS=C               LC_TELEPHONE=C             LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
#> 
#> time zone: Australia/Melbourne
#> tzcode source: system (glibc)
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] RcppSpdlog_0.0.28 ggplot2_4.0.2     dplyr_1.2.1       cellNexus_0.99.34
#> 
#> loaded via a namespace (and not attached):
#>   [1] fs_2.0.1                        matrixStats_1.5.0               spatstat.sparse_3.1-0          
#>   [4] fontawesome_0.5.3               httr_1.4.8                      RColorBrewer_1.1-3             
#>   [7] tools_4.5.3                     sctransform_0.4.3               backports_1.5.1                
#>  [10] utf8_1.2.6                      R6_2.6.1                        DT_0.34.0                      
#>  [13] HDF5Array_1.38.0                lazyeval_0.2.3                  uwot_0.2.4                     
#>  [16] rhdf5filters_1.22.0             withr_3.0.2                     sp_2.2-1                       
#>  [19] gridExtra_2.3                   nanoarrow_0.8.0                 progressr_0.19.0               
#>  [22] cli_3.6.6                       Biobase_2.70.0                  spatstat.explore_3.8-0         
#>  [25] fastDummies_1.7.5               sass_0.4.10                     Seurat_5.5.0.9002              
#>  [28] arrow_23.0.1.2                  S7_0.2.1-1                      spatstat.data_3.1-9            
#>  [31] ggridges_0.5.7                  pbapply_1.7-4                   commonmark_2.0.0               
#>  [34] parallelly_1.46.1               rstudioapi_0.18.0               generics_0.1.4                 
#>  [37] ica_1.0-3                       spatstat.random_3.4-5           Matrix_1.7-4                   
#>  [40] fansi_1.0.7                     S4Vectors_0.49.1-1              rclipboard_0.2.1               
#>  [43] abind_1.4-8                     lifecycle_1.0.5                 yaml_2.3.12                    
#>  [46] SummarizedExperiment_1.40.0     rhdf5_2.54.1                    SparseArray_1.10.10            
#>  [49] Rtsne_0.17                      grid_4.5.3                      blob_1.3.0                     
#>  [52] promises_1.5.0                  dir.expiry_1.18.0               miniUI_0.1.2                   
#>  [55] lattice_0.22-9                  cowplot_1.2.0                   pillar_1.11.1                  
#>  [58] knitr_1.51                      GenomicRanges_1.62.1            future.apply_1.20.2            
#>  [61] codetools_0.2-20                glue_1.8.0                      spatstat.univar_3.1-7          
#>  [64] tiledb_0.33.1                   data.table_1.18.2.1             tidySingleCellExperiment_1.20.1
#>  [67] vctrs_0.7.3                     png_0.1-9                       spam_2.11-3                    
#>  [70] gtable_0.3.6                    aws.s3_0.3.22                   assertthat_0.2.1               
#>  [73] cachem_1.1.0                    xfun_0.57                       S4Arrays_1.10.1                
#>  [76] mime_0.13                       Seqinfo_1.0.0                   survival_3.8-6                 
#>  [79] SingleCellExperiment_1.32.0     ellipsis_0.3.3                  fitdistrplus_1.2-6             
#>  [82] ROCR_1.0-12                     nlme_3.1-168                    tiledbsoma_2.1.2               
#>  [85] RcppCCTZ_0.2.14                 bit64_4.6.0-1                   filelock_1.0.3                 
#>  [88] RcppAnnoy_0.0.23                GenomeInfoDb_1.46.2             rprojroot_2.1.1                
#>  [91] bslib_0.10.0                    irlba_2.3.7                     KernSmooth_2.23-26             
#>  [94] otel_0.2.0                      BiocGenerics_0.56.0             DBI_1.3.0                      
#>  [97] zellkonverter_1.20.1            duckdb_1.4.3                    tidyselect_1.2.1               
#> [100] processx_3.8.7                  cellxgene.census_1.16.1         bit_4.6.0                      
#> [103] compiler_4.5.3                  curl_7.0.0                      rjsoncons_1.3.2                
#> [106] h5mread_1.2.1                   xml2_1.5.2                      nanotime_0.3.13                
#> [109] DelayedArray_0.36.1             plotly_4.12.0                   bookdown_0.46                  
#> [112] checkmate_2.3.4                 scales_1.4.0                    lmtest_0.9-40                  
#> [115] callr_3.7.6                     spdl_0.0.5                      stringr_1.6.0                  
#> [118] anndataR_1.3.1                  digest_0.6.39                   goftest_1.2-3                  
#> [121] spatstat.utils_3.2-2            rmarkdown_2.31                  basilisk_1.22.0                
#> [124] XVector_0.50.0                  htmltools_0.5.9                 pkgconfig_2.0.3                
#> [127] base64enc_0.1-6                 MatrixGenerics_1.22.0           dbplyr_2.5.2                   
#> [130] fastmap_1.2.0                   rlang_1.2.0                     htmlwidgets_1.6.4              
#> [133] UCSC.utils_1.6.1                shiny_1.13.0                    farver_2.1.2                   
#> [136] jquerylib_0.1.4                 zoo_1.8-15                      jsonlite_2.0.0                 
#> [139] magrittr_2.0.5                  dotCall64_1.2                   patchwork_1.3.2                
#> [142] Rhdf5lib_1.32.0                 Rcpp_1.1.1-1                    reticulate_1.46.0              
#> [145] stringi_1.8.7                   brio_1.1.5                      MASS_7.3-65                    
#> [148] plyr_1.8.9                      parallel_4.5.3                  listenv_0.10.1                 
#> [151] ggrepel_0.9.8                   forcats_1.0.1                   deldir_2.0-4                   
#> [154] splines_4.5.3                   tensor_1.5.1                    ps_1.9.2                       
#> [157] cellxgenedp_1.14.0              igraph_2.2.3                    spatstat.geom_3.7-3            
#> [160] RcppHNSW_0.6.0                  reshape2_1.4.5                  stats4_4.5.3                   
#> [163] evaluate_1.0.5                  ttservice_0.5.3                 SeuratObject_5.4.0             
#> [166] BiocManager_1.30.27             httpuv_1.6.17                   RANN_2.6.2                     
#> [169] tidyr_1.3.2                     purrr_1.2.2                     polyclip_1.10-7                
#> [172] future_1.70.0                   scattermore_1.2                 xtable_1.8-8                   
#> [175] RSpectra_0.16-2                 later_1.4.8                     viridisLite_0.4.3              
#> [178] tibble_3.3.1                    memoise_2.0.1                   aws.signature_0.6.0            
#> [181] IRanges_2.44.0                  cluster_2.1.8.2                 shinyWidgets_0.9.1             
#> [184] globals_0.19.1                  BiocStyle_2.38.0

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cellNexus: Quality control, annotation, aggregation and analytical layers for the Human Cell Atlas data

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