Contents

# load required packages
library(spicyR)
library(ggplot2)
library(SingleCellExperiment)

1 Installation

if (!require("BiocManager")) {
  install.packages("BiocManager")
}
BiocManager::install("spicyR")

2 Overview

This guide will provide a step-by-step guide on how mixed effects models can be applied to multiple segmented and labelled images to identify how the localisation of different cell types can change across different conditions. Here, the subject is modelled as a random effect, and the different conditions are modelled as a fixed effect.

3 Example data

Here, we use a subset of the Damond et al 2019 imaging mass cytometry dataset. We will compare the spatial distributions of cells in the pancreatic islets of individuals with early onset diabetes and healthy controls.

diabetesData_SCE is a SingleCellExperiment object containing single-cell data of 160 images from 8 subjects, with 20 images per subjects.

data("diabetesData_SCE")
diabetesData_SCE
#> class: SingleCellExperiment 
#> dim: 0 253777 
#> metadata(0):
#> assays(0):
#> rownames: NULL
#> rowData names(0):
#> colnames: NULL
#> colData names(11): imageID cellID ... group stage
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):

In this data set, cell types include immune cell types (B cells, naive T cells, T Helper cells, T cytotoxic cells, neutrophils, macrophages) and pancreatic islet cells (alpha, beta, gamma, delta).

4 Mixed Effects Modelling

To investigate changes in localisation between two different cell types, we measure the level of localisation between two cell types by modelling with the L-function. Specifically, the mean difference between the obtained function and the theoretical function is used as a measure for the level of localisation. Differences of this statistic between two conditions is modelled using a weighted mixed effects model, with condition as the fixed effect and subject as the random effect.

4.1 Testing for change in localisation for a specific pair of cells

Firstly, we can test whether one cell type tends to be more localised with another cell type in one condition compared to the other. This can be done using the spicy() function, where we include condition, and subject. In this example, we want to see whether or not Delta cells (to) tend to be found around Beta cells (from) in onset diabetes images compared to non-diabetic images.

spicyTestPair <- spicy(
  diabetesData_SCE,
  condition = "stage",
  subject = "case",
  from = "beta",
  to = "delta"
)

topPairs(spicyTestPair)
#>             intercept coefficient     p.value  adj.pvalue from    to
#> beta__delta   179.729   -58.24478 0.000109702 0.000109702 beta delta

We obtain a spicy object which details the results of the mixed effects modelling performed. As the coefficient in spicyTest is positive, we find that Th cells cells are more likely to be found near beta cells in the onset diabetes group compared to the non-diabetic control.

4.2 Test for change in localisation for all pairwise cell combinations

Here, we can perform what we did above for all pairwise combinations of cell types by excluding the from and to parameters from spicy().

spicyTest <- spicy(
  diabetesData_SCE,
  condition = "stage",
  subject = "case"
)

spicyTest
#>         conditionOnset conditionLong-duration 
#>                      0                     15
topPairs(spicyTest)
#>                          intercept coefficient      p.value adj.pvalue
#> beta__delta           1.815458e+02  -48.735693 0.0005033247 0.07169649
#> delta__beta           1.817943e+02  -48.166076 0.0005601288 0.07169649
#> B__unknown            4.327556e-15   11.770938 0.0052338392 0.42051606
#> delta__delta          2.089550e+02  -52.061196 0.0125129422 0.42051606
#> unknown__macrophage   1.007337e+01  -15.826919 0.0207410908 0.42051606
#> unknown__B            0.000000e+00   12.142848 0.0225855404 0.42051606
#> macrophage__unknown   1.004424e+01  -14.471666 0.0244668075 0.42051606
#> B__Th                 3.142958e-15   26.847934 0.0245039854 0.42051606
#> otherimmune__naiveTc -9.292508e+00   33.584755 0.0255812944 0.42051606
#> ductal__ductal        1.481580e+01   -8.632569 0.0266935703 0.42051606
#>                             from         to
#> beta__delta                 beta      delta
#> delta__beta                delta       beta
#> B__unknown                     B    unknown
#> delta__delta               delta      delta
#> unknown__macrophage      unknown macrophage
#> unknown__B               unknown          B
#> macrophage__unknown   macrophage    unknown
#> B__Th                          B         Th
#> otherimmune__naiveTc otherimmune    naiveTc
#> ductal__ductal            ductal     ductal

Again, we obtain a spicy object which outlines the result of the mixed effects models performed for each pairwise combination if cell types.

We can represent this as a heatmap using the signifPlot() function by providing it the spicy object obtained.

signifPlot(
  spicyTest,
  breaks = c(-3, 3, 1),
  marksToPlot = c(
    "alpha", "beta", "gamma", "delta",
    "B", "naiveTc", "Th", "Tc", "neutrophil", "macrophage"
  )
)

5 sessionInfo()

sessionInfo()
#> R version 4.3.1 (2023-06-16)
#> Platform: x86_64-pc-linux-gnu (64-bit)
#> Running under: Ubuntu 22.04.3 LTS
#> 
#> Matrix products: default
#> BLAS:   /home/biocbuild/bbs-3.17-bioc/R/lib/libRblas.so 
#> LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.10.0
#> 
#> locale:
#>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
#>  [3] LC_TIME=en_GB              LC_COLLATE=C              
#>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
#>  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
#>  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
#> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
#> 
#> time zone: America/New_York
#> tzcode source: system (glibc)
#> 
#> attached base packages:
#> [1] stats4    stats     graphics  grDevices utils     datasets  methods  
#> [8] base     
#> 
#> other attached packages:
#>  [1] SingleCellExperiment_1.22.0 SummarizedExperiment_1.30.2
#>  [3] Biobase_2.60.0              GenomicRanges_1.52.0       
#>  [5] GenomeInfoDb_1.36.2         IRanges_2.34.1             
#>  [7] S4Vectors_0.38.1            BiocGenerics_0.46.0        
#>  [9] MatrixGenerics_1.12.3       matrixStats_1.0.0          
#> [11] ggplot2_3.4.3               spicyR_1.12.2              
#> [13] BiocStyle_2.28.0           
#> 
#> loaded via a namespace (and not attached):
#>   [1] RColorBrewer_1.1-3          jsonlite_1.8.7             
#>   [3] MultiAssayExperiment_1.26.0 magrittr_2.0.3             
#>   [5] spatstat.utils_3.0-3        magick_2.7.5               
#>   [7] farver_2.1.1                nloptr_2.0.3               
#>   [9] rmarkdown_2.24              zlibbioc_1.46.0            
#>  [11] vctrs_0.6.3                 minqa_1.2.5                
#>  [13] spatstat.explore_3.2-1      DelayedMatrixStats_1.22.6  
#>  [15] RCurl_1.98-1.12             rstatix_0.7.2              
#>  [17] htmltools_0.5.6             S4Arrays_1.0.6             
#>  [19] broom_1.0.5                 Rhdf5lib_1.22.0            
#>  [21] rhdf5_2.44.0                sass_0.4.7                 
#>  [23] bslib_0.5.1                 plyr_1.8.8                 
#>  [25] cachem_1.0.8                lifecycle_1.0.3            
#>  [27] pkgconfig_2.0.3             Matrix_1.6-1               
#>  [29] R6_2.5.1                    fastmap_1.1.1              
#>  [31] GenomeInfoDbData_1.2.10     digest_0.6.33              
#>  [33] numDeriv_2016.8-1.1         colorspace_2.1-0           
#>  [35] tensor_1.5                  dqrng_0.3.0                
#>  [37] ggpubr_0.6.0                beachmat_2.16.0            
#>  [39] labeling_0.4.3              fansi_1.0.4                
#>  [41] spatstat.sparse_3.0-2       polyclip_1.10-4            
#>  [43] abind_1.4-5                 mgcv_1.9-0                 
#>  [45] compiler_4.3.1              withr_2.5.0                
#>  [47] backports_1.4.1             BiocParallel_1.34.2        
#>  [49] carData_3.0-5               highr_0.10                 
#>  [51] HDF5Array_1.28.1            ggforce_0.4.1              
#>  [53] R.utils_2.12.2              ggsignif_0.6.4             
#>  [55] MASS_7.3-60                 concaveman_1.1.0           
#>  [57] DelayedArray_0.26.7         rjson_0.2.21               
#>  [59] tools_4.3.1                 goftest_1.2-3              
#>  [61] R.oo_1.25.0                 glue_1.6.2                 
#>  [63] nlme_3.1-163                rhdf5filters_1.12.1        
#>  [65] grid_4.3.1                  ClassifyR_3.4.9            
#>  [67] reshape2_1.4.4              generics_0.1.3             
#>  [69] gtable_0.3.4                spatstat.data_3.0-1        
#>  [71] R.methodsS3_1.8.2           tidyr_1.3.0                
#>  [73] data.table_1.14.8           car_3.1-2                  
#>  [75] utf8_1.2.3                  XVector_0.40.0             
#>  [77] spatstat.geom_3.2-4         pillar_1.9.0               
#>  [79] stringr_1.5.0               limma_3.56.2               
#>  [81] splines_4.3.1               dplyr_1.1.2                
#>  [83] tweenr_2.0.2                lattice_0.21-8             
#>  [85] survival_3.5-7              deldir_1.0-9               
#>  [87] tidyselect_1.2.0            locfit_1.5-9.8             
#>  [89] scuttle_1.10.2              knitr_1.43                 
#>  [91] bookdown_0.35               edgeR_3.42.4               
#>  [93] xfun_0.40                   DropletUtils_1.20.0        
#>  [95] pheatmap_1.0.12             scam_1.2-14                
#>  [97] stringi_1.7.12              yaml_2.3.7                 
#>  [99] boot_1.3-28.1               evaluate_0.21              
#> [101] codetools_0.2-19            tibble_3.2.1               
#> [103] BiocManager_1.30.22         cli_3.6.1                  
#> [105] munsell_0.5.0               jquerylib_0.1.4            
#> [107] Rcpp_1.0.11                 spatstat.random_3.1-5      
#> [109] parallel_4.3.1              sparseMatrixStats_1.12.2   
#> [111] bitops_1.0-7                lme4_1.1-34                
#> [113] SpatialExperiment_1.10.0    lmerTest_3.1-3             
#> [115] scales_1.2.1                purrr_1.0.2                
#> [117] crayon_1.5.2                rlang_1.1.1