Barrett's esophagus (BE) is the replacement of the normal squamous esophageal epithelium with an intestinalized columnar epithelium. It occurs in response to chronic acid and bile reflux and is an important risk factor for the development of esophageal adenocarcinoma (EAC). BE is thought to be an adaptive response to chronic tissue injury and the release of pro-inflammatory prostaglandins and cytokines. However, the mechanisms underpinning BE pathogenesis remain poorly understood in part due to the paucity of experimental animal models. The development of innovative, genetically based and physiologically relevant mouse models for BE is an important long-term objective of my lab. Cox-1 and Cox-2 are the rate-limiting enzymes in prostaglandin biosynthesis. Cox-2 expression is induced in the esophagus by acid reflux, and the inhibition of Cox-2 reduces the progression to BE and cancer in a rat bile reflux model. Cox-2 is also known to increase intracellular oxidative stress and damage DNA. Nevertheless, a role for Cox-2 in the pathogenesis of BE and EAC has not been tested. We have utilized a novel 3D in vitro cell culture system to model BE pathogenesis. When we express Cox-2 in normal human esophageal keratinocytes we observe the development of intestinal mucin-filled cysts. This suggests that Cox-2 expression is sufficient to induce an altered cell lineage from keratinocytes, one that has mucin-secretory features consistent with BE cells. We therefore hypothesize that Cox-2 expression in the murine esophagus results in a chronic esophagitis that models GERD esophagitis by provoking oxidative stress, DNA damage, and the development of metaplasia and dysplasia. The rationale for the proposed research is that while a role for Cox-2 in the pathogenesis of Barrett's esophagus is suggested by clinical observational data, this has not been proven in animal models. Once it is established, greater consideration can be given to pharmacological approaches to prevent the onset of BE and limit progression to cancer. Guided by strong preliminary data, this hypothesis will be tested by the following inter-related Specific Aims: 1) Does chronic Cox-2 activity in the esophagus of K14-Cox2 mice result in inflammation, oxidative stress, DNA damage, and the adoption of an altered differentiation program? 2) Can a diminished antioxidant response or defective DNA repair synergize with esophageal Cox-2 expression to accelerate the onset of DNA damage, metaplasia, and dysplasia? Summary BE is an increasingly common precancerous condition and an emerging U.S. health problem. Our studies are significant because they mechanistically explore the contributions of Cox2 to BE pathogenesis, and we anticipate our approaches will yield improved mouse models for BE. Additionally, as a Midcareer Investigator Award, this study will provide an outstanding focus for the PI to: 1) advance his skills in mouse pathobiology research and comprehensive phenotyping;2) serve as a basis for mentoring of junior investigators in these areas;and 3) Conduct state-of-the-art biomedical research in mouse pathobiology.

Public Health Relevance

The proposed research is relevant to public health because Barrett's metaplasia is a condition in humans in which the normal squamous esophageal mucosa is replaced with an intestinalized columnar epithelium. It is an increasingly common precancerous condition and an emerging health problem in the US. Barrett's esophagus is associated with chronic acid reflux, and at present there is little known about the mechanisms giving rise Barrett's metaplasia. This proposal describes approaches to mechanistically explore the contributions of Cox-2, oxidative stress and DNA damage, inflammation, bile reflux, and to BE pathogenesis using a novel mouse transgenic model. We anticipate our approaches will yield improved mouse models and novel therapeutic and preventive strategies that will improve patient care for this important clinical condition. Thus, tis proposed research is relevant to the part of NIH's mission that pertains to developing fundamental knowledge that will help to reduce the burdens of human diseases through the power of mouse pathobiology.

Agency
National Institute of Health (NIH)
Institute
Office of The Director, National Institutes of Health (OD)
Type
Midcareer Investigator Award in Biomedical and Behavioral Research (K26)
Project #
1K26OD012097-01A1
Application #
8509309
Study Section
Special Emphasis Panel (ZTR1-CM-6 (01))
Program Officer
Mirochnitchenko, Oleg
Project Start
2013-06-13
Project End
2018-03-31
Budget Start
2013-06-13
Budget End
2014-03-31
Support Year
1
Fiscal Year
2013
Total Cost
$147,306
Indirect Cost
$10,912
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Fecteau, Ryan E; Kong, Jianping; Kresak, Adam et al. (2016) Association Between Germline Mutation in VSIG10L and Familial Barrett Neoplasia. JAMA Oncol 2:1333-1339
Kong, Jianping; Whelan, Kelly A; Laczkó, Dorottya et al. (2016) Autophagy levels are elevated in barrett's esophagus and promote cell survival from acid and oxidative stress. Mol Carcinog 55:1526-1541
Pattison, Amanda M; Blomain, Erik S; Merlino, Dante J et al. (2016) Intestinal Enteroids Model Guanylate Cyclase C-Dependent Secretion Induced by Heat-Stable Enterotoxins. Infect Immun 84:3083-91
Nakagawa, Hiroshi; Whelan, Kelly; Lynch, John P (2015) Mechanisms of Barrett's oesophagus: intestinal differentiation, stem cells, and tissue models. Best Pract Res Clin Gastroenterol 29:3-16
Kong, Jianping; Sai, Hong; Crissey, Mary Ann S et al. (2015) Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia. Oncotarget 6:32980-3005
Abrams, Julian A; Appelman, Henry D; Beer, David G et al. (2014) Barrett's Esophagus Translational Research Network (BETRNet): the pivotal role of multi-institutional collaboration in esophageal adenocarcinoma research. Gastroenterology 146:1586-90
Hartman, Kira G; Bortner Jr, James D; Falk, Gary W et al. (2014) Modeling human gastrointestinal inflammatory diseases using microphysiological culture systems. Exp Biol Med (Maywood) 239:1108-23
Vega, Maria E; Giroux, Véronique; Natsuizaka, Mitsuteru et al. (2014) Inhibition of Notch signaling enhances transdifferentiation of the esophageal squamous epithelium towards a Barrett's-like metaplasia via KLF4. Cell Cycle 13:3857-66
Hartman, Kira G; Bortner, James D; Falk, Gary W et al. (2013) Modeling inflammation and oxidative stress in gastrointestinal disease development using novel organotypic culture systems. Stem Cell Res Ther 4 Suppl 1:S5
Magness, Scott T; Puthoff, Brent J; Crissey, Mary Ann et al. (2013) A multicenter study to standardize reporting and analyses of fluorescence-activated cell-sorted murine intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 305:G542-51

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