TY - JOUR
T1 - NOD-Like Receptor Protein 3 Inflammasome Priming and Activation in Barrett's Epithelial Cells
AU - Nadatani, Yuji
AU - Huo, Xiaofang
AU - Zhang, Xi
AU - Yu, Chunhua
AU - Cheng, Edaire
AU - Zhang, Qiuyang
AU - Dunbar, Kerry B.
AU - Theiss, Arianne
AU - Pham, Thai H.
AU - Wang, David H.
AU - Watanabe, Toshio
AU - Fujiwara, Yasuhiro
AU - Arakawa, Tetsuo
AU - Spechler, Stuart J.
AU - Souza, Rhonda F.
N1 - Funding Information:
Funding Supported by Merit Review Award BX002666 from the US Department of Veterans Affairs Biomedical Laboratory Research Program (S.J.S.), the National Institutes of Health (R01-DK63621 to R.F.S. and S.J.S., K12 HD-068369-01 and K08-DK099383 to E.C., and R01-DK097340 to D.H.W.). This material is the result of work supported with resources and the use of facilities at the Dallas VA Medical Center. The contents do not represent the views of the US Department of Veterans Affairs or the United States Government.
Publisher Copyright:
© 2016 The Authors.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - Background & Aims: Microbial molecular products incite intestinal inflammation by activating Toll-like receptors (TLRs) and inflammasomes of the innate immune system. This system's contribution to esophageal inflammation is not known. Gram-negative bacteria, which dominate the esophageal microbiome in reflux esophagitis, produce lipopolysaccharide (LPS), a TLR4 ligand. TLR4 signaling produces pro-interleukin (IL)1β, pro-IL18, and NOD-like receptor protein 3 (NLRP3), which prime the NLRP3 inflammasome. Subsequent NLRP3 inflammasome activation cleaves caspase-1, inducing secretion of proinflammatory cytokines and pyroptosis (inflammatory cell death). We explored LPS effects on NLRP3 inflammasome priming and activation in esophageal cells. Methods: We exposed esophageal squamous and Barrett's epithelial cells to LPS and measured the following: (1) TLR4, pro-IL1β, pro-IL18, and NLRP3 expression; (2) caspase-1 activity; (3) tumor necrosis factor-α, IL8, IL1β, and IL18 secretion; (4) lactate dehydrogenase (LDH) release (a pyroptosis marker); and (5) mitochondrial reactive oxygen species (ROS). As inhibitors, we used acetyl-Tyr-Val-Ala-Asp-CHO for caspase-1, small interfering RNA for NLRP3, and (2-(2,2,6,6,-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride for mitochondrial ROS. Results: Squamous and Barrett's cells expressed similar levels of TLR4, but LPS induced TLR4 signaling that increased tumor necrosis factor-α and IL8 secretion only in Barrett's cells. Barrett's cells treated with LPS showed increased expression of pro-IL18, pro-IL1β, and NLRP3, and increased mitochondrial ROS levels, caspase-1 activity, IL1β and IL18 secretion, and LDH release. Acetyl-Tyr-Val-Ala-Asp-CHO, NLRP3 small interfering RNA, and Mito-TEMPO all blocked LPS-induced IL1β and IL18 secretion and LDH release. Conclusions: In Barrett's cells, LPS both primes and activates the NLRP3 inflammasome, causing secretion of proinflammatory cytokines and pyroptosis. By triggering molecular events promoting inflammation, the esophageal microbiome might contribute to inflammation-mediated carcinogenesis in Barrett's esophagus.
AB - Background & Aims: Microbial molecular products incite intestinal inflammation by activating Toll-like receptors (TLRs) and inflammasomes of the innate immune system. This system's contribution to esophageal inflammation is not known. Gram-negative bacteria, which dominate the esophageal microbiome in reflux esophagitis, produce lipopolysaccharide (LPS), a TLR4 ligand. TLR4 signaling produces pro-interleukin (IL)1β, pro-IL18, and NOD-like receptor protein 3 (NLRP3), which prime the NLRP3 inflammasome. Subsequent NLRP3 inflammasome activation cleaves caspase-1, inducing secretion of proinflammatory cytokines and pyroptosis (inflammatory cell death). We explored LPS effects on NLRP3 inflammasome priming and activation in esophageal cells. Methods: We exposed esophageal squamous and Barrett's epithelial cells to LPS and measured the following: (1) TLR4, pro-IL1β, pro-IL18, and NLRP3 expression; (2) caspase-1 activity; (3) tumor necrosis factor-α, IL8, IL1β, and IL18 secretion; (4) lactate dehydrogenase (LDH) release (a pyroptosis marker); and (5) mitochondrial reactive oxygen species (ROS). As inhibitors, we used acetyl-Tyr-Val-Ala-Asp-CHO for caspase-1, small interfering RNA for NLRP3, and (2-(2,2,6,6,-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride for mitochondrial ROS. Results: Squamous and Barrett's cells expressed similar levels of TLR4, but LPS induced TLR4 signaling that increased tumor necrosis factor-α and IL8 secretion only in Barrett's cells. Barrett's cells treated with LPS showed increased expression of pro-IL18, pro-IL1β, and NLRP3, and increased mitochondrial ROS levels, caspase-1 activity, IL1β and IL18 secretion, and LDH release. Acetyl-Tyr-Val-Ala-Asp-CHO, NLRP3 small interfering RNA, and Mito-TEMPO all blocked LPS-induced IL1β and IL18 secretion and LDH release. Conclusions: In Barrett's cells, LPS both primes and activates the NLRP3 inflammasome, causing secretion of proinflammatory cytokines and pyroptosis. By triggering molecular events promoting inflammation, the esophageal microbiome might contribute to inflammation-mediated carcinogenesis in Barrett's esophagus.
KW - Cytokine
KW - Esophageal squamous cell
KW - GERD
KW - IL1β
KW - Pyroptosis
UR - http://www.scopus.com/inward/record.url?scp=84975311521&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84975311521&partnerID=8YFLogxK
U2 - 10.1016/j.jcmgh.2016.03.006
DO - 10.1016/j.jcmgh.2016.03.006
M3 - Article
C2 - 27777967
AN - SCOPUS:84975311521
SN - 2352-345X
VL - 2
SP - 439
EP - 453
JO - CMGH
JF - CMGH
IS - 4
ER -