title: Aryl Hydrocarbon Receptor Ligands in Cigarette Smoke Induce Production of Interleukin-22 to Promote Pancreatic Fibrosis in Models of Chronic Pancreatitis.
abstract: Cigarette smoke has been identified as an independent risk factor for chronic pancreatitis (CP). Little is known about the mechanisms by which smoking promotes development of CP. We assessed the effects of aryl hydrocarbon receptor (AhR) ligands found in cigarette smoke on immune cell activation in humans and pancreatic fibrosis in animal models of CP.
  
  
  
  We obtained serum samples from patients with CP treated at Stanford University hospital and healthy individuals (controls) and isolated CD4+T cells. Levels of interleukin-22 (IL22) were measured by enzyme-linked immunosorbent assay and smoking histories were collected. T cells from healthy nonsmokers and smokers were stimulated and incubated with AhR agonists (2,3,7,8-tetrachlorodibenzo-p-dioxin or benzo[a]pyrene) or antagonists and analyzed by flow cytometry. Mice were given intraperitoneal injections of caerulein or saline, with or without lipopolysaccharide, to induce CP. Some mice were given intraperitoneal injections of AhR agonists at the start of caerulein injection, with or without an antibody against IL22 (anti-IL22) starting 2 weeks after the first caerulein injection, or recombinant mouse IL22 or vehicle (control) intraperitoneally 4 weeks after the first caerulein injection. Mice were exposed to normal air or cigarette smoke for 6 h/d for 7 weeks and expression of AhR gene targets was measured. Pancreata were collected from all mice and analyzed by histology and quantitative reverse transcription polymerase chain reaction. Pancreatic stellate cells and T cells were isolated and studied using immunoblot, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent analyses.
  
  
  
  Mice given AhR agonists developed more severe pancreatic fibrosis (based on decreased pancreas size, histology, and increased expression of fibrosis-associated genes) than mice not given agonists after caerulein injection. In mice given saline instead of caerulein, AhR ligands did not induce fibrosis. Pancreatic T cells from mice given AhR agonists and caerulein were activated and expressed IL22, but not IL17 or interferon gamma. Human T cells exposed to AhR agonists up-regulated expression of IL22. In mice given anti-IL22, pancreatic fibrosis did not progress, whereas mice given recombinant IL22 had a smaller pancreas and increased fibrosis. Pancreatic stellate cells isolated from mouse and human pancreata expressed the IL22 receptor IL22RA1. Incubation of the pancreatic stellate cells with IL22 induced their expression of the extracellular matrix genes fibronectin 1 and collagen type I α1 chain, but not α2 smooth muscle actin or transforming growth factor-β. Serum samples from smokers had significantly higher levels of IL22 than those from nonsmokers.
  
  
  
  AhR ligands found in cigarette smoke increase the severity of pancreatic fibrosis in mouse models of pancreatitis via up-regulation of IL22. This pathway might be targeted for treatment of CP and serve as a biomarker of disease.
authors: State Key Laboratory of Oncogenes and Related Genes, Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California. Electronic address: jingxue@sjtu.edu.cn.
authors: Jing
authors: J
authors: Xue
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Qinglan
authors: Q
authors: Zhao
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Vishal
authors: V
authors: Sharma
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Linh P
authors: LP
authors: Nguyen
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Yvonne N
authors: YN
authors: Lee
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Kim L
authors: KL
authors: Pham
authors: Cedars-Sinai Medical Center and Department of Veterans Affairs, Los Angeles, California.
authors: Mouad
authors: M
authors: Edderkaoui
authors: Cedars-Sinai Medical Center and Department of Veterans Affairs, Los Angeles, California.
authors: Stephen J
authors: SJ
authors: Pandol
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California.
authors: Walter
authors: W
authors: Park
authors: Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California. Electronic address: aidah@stanford.edu.
authors: Aida
authors: A
authors: Habtezion
mesh_terms: D000199:Actins / Q000235:genetics; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001564:Benzo(a)pyrene / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D002478:Cells, Cultured; D002108:Ceruletide; D024042:Collagen Type I / Q000235:genetics; D000090602:Collagen Type I, alpha 1 Chain; D004195:Disease Models, Animal; D005353:Fibronectins / Q000235:genetics; D005355:Fibrosis; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism; D007378:Interleukins / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D008024:Ligands; D008213:Lymphocyte Activation; D051379:Mice; D010179:Pancreas / Q000473:pathology*; D058954:Pancreatic Stellate Cells / Q000737:chemistry; D050500:Pancreatitis, Chronic / Q000139:chemically induced / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists / Q000037:antagonists & inhibitors; D018123:Receptors, Interleukin / Q000032:analysis; D012906:Smoke; D012907:Smoking / Q000276:immunology; D062789:Tobacco Products; D016212:Transforming Growth Factor beta / Q000235:genetics; D000097043:Interleukin-22
chemical_list: D000199:Actins; D000906:Antibodies; D001564:Benzo(a)pyrene; D002108:Ceruletide; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D005353:Fibronectins; D007371:Interferon-gamma; D020381:Interleukin-17; D007378:Interleukins; D008024:Ligands; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D018123:Receptors, Interleukin; D012906:Smoke; D016212:Transforming Growth Factor beta; D000097043:Interleukin-22; C558396:Acta2 protein, mouse; C067625:FN1 protein, human; C415369:interleukin-22 receptor
keywords: BaP; CP; Immune Regulation; PSC; TCDD