Background and Aims: Primary sclerosing cholangitis (PSC) is a cholangiopathy of unknown etiology featuring
peribiliary infiltration and fibrosis. To identify novel PSC pathways, we analyzed
liver explants using spatial and single-nuclei transcriptomics (snRNA-seq) and compared
differential expressed genes (DEGs) across biliary regions in early and advanced PSC.
Methods: Fresh-frozen liver explants from PSC patients (4 recurrent cholangitis, 7 dysplasia,12
cirrhotic) and cirrhotic controls (4 ALD, 3 MASH) were analyzed by spatial transcriptomics
(Visium,10X Genomics). Sixteen of the same explants (12 PSC, 4 controls) were assessed
by snRNA-seq (Chromium 3’, 10X Genomics). Spatial and snRNA-seq transcripts were clustered
using Seurat v5.0.0 (Satija Lab, Broad Institute/MIT) and all DEGs reported reached
statistical significance (P-adj<0.001).
Results: To identify unique PSC pathways, we first classified liver regions as early or advanced
disease using histology features and fibrosis markers detected by spatial transcriptomics
(COL1A1/2+COL3A1, COL6A2). Local profiling of biliary regions (KRT19+FXYD2+) by spatial
transcriptomics revealed robust expression of metallothionein genes MT1E, MT1G and
MT1H (14.9-fold) and inflammatory SAA1 and SAA2 (8.4-fold) by peribiliary hepatocytes
at the interface between early and advanced PSC compared to controls. snRNA-seq identified
9 distinct liver cell types and showed highest metallothionein expression in PSC hepatocytes.
Moreover, elevated metallothionein correlated with features of liver decompensation
and cholestasis, including decreased serum sodium and elevated serum bilirubin.
Conclusions: Metallothionein is highly overrepresented in peribiliary regions at all stages of
PSC suggesting that metallothionein may be triggered by early cholangiopathy in PSC
livers.