Macrophage signaling associates with fibrogenic program activation in periductal fibroblasts in pediatric primary sclerosing cholangitis.

Abstract

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic cholestatic liver disease characterized by inflammation and fibrosis of the bile ducts, yet the cellular crosstalk driving periductal fibrosis remains poorly defined. This study applied a multi-omics approach integrating spatial transcriptomics, RNA-seq, and proteomics to characterize fibrotic periductal regions and their cell-cell communications. Macrophages (MP) subsets, including monocyte-drived-(Mo)MP and lipid-associated-macrophage (LAM)-like, co-localized with cholangiocytes, lymphocytes, and hepatic stellate cells (HSC1). Cell niche analysis identified periductal regions with elevated fibrotic signals, where cell-cell communication analysis revealed potential MP-HSC interactions involving 17 fibrotic driver genes in MP, including ITGB2, GRN, and CCL21, and 6 fibrotic effector genes in HSC. In validation analyses, bulk RNA-seq data showed higher driver and effector gene expression in PSC with established fibrosis compared to early-stage PSC or healthy control (HC). Plasma proteins encoded by MP driver genes were elevated in PSC and in patients with elevated (≥3.29 kPa) liver stiffness on MR elastography. Furthermore, immunofluorescence and SHG imaging showed enrichment of CD68+/CD18+(ITGB2) macrophages in fibrotic regions of PSC liver biopsies. These findings revealed enrichment of MoMP and LAM-like macrophages in fibrotic regions and suggest that they likely contribute to fibrotic activation of nearby HSCs in PSC.