Single-cell sequencing unveils distinct immune microenvironments with CCR6-CCL20 crosstalk in human chronic pancreatitis

Abstract

ObjectiveChronic pancreatitis (CP) is a potentially fatal disease of the exocrine pancreas, with no specific or effective approved therapies. Due to difficulty in accessing pancreas tissues, little is known about local immune responses or pathogenesis in human CP. We sought to characterise pancreatic immune responses using tissues derived from patients with different aetiologies of CP and non-CP organ donors in order to identify key signalling molecules associated with human CP.DesignWe performed single-cell level cellular indexing of transcriptomes and epitopes by sequencing and T-cell receptor (TCR) sequencing of pancreatic immune cells isolated from organ donors, hereditary and idiopathic patients with CP who underwent total pancreatectomy. We validated gene expression data by performing flow cytometry and functional assays in a second patient with CP cohort.ResultsDeep single-cell sequencing revealed distinct immune characteristics and significantly enriched CCR6+ CD4+ T cells in hereditary compared with idiopathic CP. In hereditary CP, a reduction in T-cell clonality was observed due to the increased CD4+ T (Th) cells that replaced tissue-resident CD8+ T cells. Shared TCR clonotype analysis among T-cell lineages also unveiled unique interactions between CCR6+ Th and Th1 subsets, and TCR clustering analysis showed unique common antigen binding motifs in hereditary CP. In addition, we observed a significant upregulation of the CCR6 ligand (CCL20) expression among monocytes in hereditary CP as compared with those in idiopathic CP. The functional significance of CCR6 expression in CD4+ T cells was confirmed by flow cytometry and chemotaxis assay.ConclusionSingle-cell sequencing with pancreatic immune cells in human CP highlights pancreas-specific immune crosstalk through the CCR6-CCL20 axis, a signalling pathway that might be leveraged as a potential future target in human hereditary CP.

Single-Cell Transcriptomic Analysis of the Mouse Pancreas: Characteristic Features of Pancreatic Ductal Cells in Chronic Pancreatitis

“…In contrast, an enormous immune cell population was detected in the CP group, including B cells, T cells, plasma cells, macrophages, and neutrophils. According to Lee et al’s study, T cells are the major immune cell type in the pancreas of CP patients [ 14 ]. The overabundant B cells and plasma cells in the CP group could be caused by species differences or modeling methods.…”

“…Recently, Tosti et al utilized single nuclear RNA sequencing (snRNA-seq) to generate transcriptome profiles of the pancreas from healthy neonates, healthy adults, and CP patients [ 12 ]. Single-cell analyses by Blobner et al demonstrated two unique clusters of acinar cells in human CP [ 13 ], and Lee et al’s study revealed distinct immune microenvironments in human hereditary and idiopathic CP [ 14 ]. These findings contribute to our understanding of the complex pancreatic genomic landscape and the cellular foundations of CP.…”

CCR6 as a Potential Target for Therapeutic Antibodies for the Treatment of Inflammatory Diseases

“…CCR6 has also been related to chronic pancreatitis in a single-cell sequencing analysis with pancreatic immune cells. Single-cell sequencing revealed that the CCR6/CCL20 axis is upregulated in hereditary chronic pancreatitis when compared with idiopathic chronic pancreatitis; therefore, this signaling pathway could be a potential target in human hereditary chronic pancreatitis [ 69 ].…”

Research progress on application of single-cell TCR/BCR sequencing technology to the tumor immune microenvironment, autoimmune diseases, and infectious diseases

“…Single-cell sequencing of pancreatic immune cells isolated from hereditary and idiopathic chronic pancreatitis (CP) patients undergoing total pancreatectomy has revealed reduced T-cell clonicity in hereditary CP, and C-C motif chemokine receptor 6 (CCR6) ligand (CCL20) expression is significantly upregulated in monocytes of hereditary CP. The CCR6-CCL20 signaling pathway may be used as a potential therapeutic target for human inherited CP ( 34 ). The detection of TCR+ macrophages, proliferative macrophages, and natural killer dendritic cells in peritoneal fluid of endometriosis by single-cell sequencing suggests that immune dysfunction occurs in the peritoneal fluid of endometriosis and provides a valuable tool for the future development of immunotherapy ( 35 ).…”