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

Bomi Lee; Hong Namkoong; Yan Yang; Huang Huang; David Heller; Gregory L Szot; Mark M Davis; Sohail Z Husain; Stephen J Pandol; Melena D Bellin; Aida Habtezion

doi:10.1136/gutjnl-2021-324546

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

Gut. 2022 Sep;71(9):1831-1842. doi: 10.1136/gutjnl-2021-324546. Epub 2021 Oct 26.

Authors

Bomi Lee^{1

2}, Hong Namkoong³, Yan Yang⁴, Huang Huang⁵, David Heller⁶, Gregory L Szot⁷, Mark M Davis^{5

8

9}, Sohail Z Husain², Stephen J Pandol¹⁰, Melena D Bellin^{6

11}, Aida Habtezion^{1

5}

Affiliations

¹ Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, Stanford University, Stanford, California, USA bomilee@stanford.edu aidah@stanford.edu.
² Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, School of Medicine, Stanford University, Stanford, California, USA.
³ Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, Stanford University, Stanford, California, USA.
⁴ Stanford Center for Genomics and Personalized Medicine, Stanford University, Stanford, California, USA.
⁵ Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, California, USA.
⁶ Department of Surgery, Schulze Diabetes Institute, University of Minnesota Medical Center, Minneapolis, Minnesota, USA.
⁷ Department of Surgery, Division of Transplantation, University of California San Francisco, San Francisco, California, USA.
⁸ Department of Microbiology and Immunology, Stanford Medicine, Stanford, California, USA.
⁹ Howard Hughes Medical Institute, Stanford University, Stanford, California, USA.
¹⁰ Basic and Translational Pancreatic Research, Cedars Sinai Medical Center, Los Angeles, California, USA.
¹¹ Department of Pediatrics, University of Minnesota Medical Center and Masonic Children's Hospital, Minneapolis, Minnesota, USA.

Abstract

Objective: Chronic 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.

Design: We 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.

Results: Deep 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.

Conclusion: Single-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.

Keywords: RNA expression; T-cell receptor; chronic pancreatitis; immunology; pancreatitis.

Publication types

Research Support, Non-U.S. Gov't
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Adaptive Immunity
CD8-Positive T-Lymphocytes
Chemokine CCL20 / metabolism
Flow Cytometry
Humans
Pancreatitis, Chronic* / genetics
Receptors, CCR6* / genetics
Receptors, CCR6* / metabolism

Substances

CCL20 protein, human
CCR6 protein, human
Chemokine CCL20
Receptors, CCR6

Abstract

Publication types

MeSH terms

Substances

Grants and funding