Triggering receptor expressed on myeloid cells-1 (TREM-1) expression on gastric epithelium: implication for a role of TREM-1 in Helicobacter pylori infection.
In Helicobacter pylori gastritis gastric epithelium plays a central role in the innate immunity to H. pylori. However, epithelial receptors interacting with H. pylori have been poorly characterized so far. Recently a new triggering receptor expressed on myeloid cells-1 (TREM-1) has been identified on human neutrophils and monocytes. On these cells TREM-1 triggers innate immunity by stimulating the secretion of interleukin (IL)-8 and tumour necrosis factor (TNF)-alpha and thus amplifies bacterial-induced inflammation. In this study expression and function of TREM-1 in gastric epithelium exposed to H. pylori has been investigated. TREM-1 mRNA and protein were expressed on gastric epithelial cell lines as demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence activated cell sorter analysis. Gastric epithelial TREM-1 expression was up-regulated directly by H. pylori and was independent of epithelial IL-8 induced by H. pylori. Immunohistochemistry and tissue RT-PCR demonstrated significantly stronger TREM-1 expression in H. pylori gastritis compared with the non-inflamed gastric mucosa supporting in vivo that epithelial TREM-1 is up-regulated during H. pylori infection. Stimulation of gastric epithelial TREM-1 receptor resulted in IL-8 up-regulation on mRNA and protein level, as shown by real-time PCR and immunoassay. This is the first study localizing TREM-1 on gastric epithelium. Functional data suggest that TREM-1 expressed on gastric epithelium amplifies inflammation of the underlying gastric mucosa by up-regulation of IL-8.
Schmausser
B
B
Institut für Pathologie der Universität Würzburg, Würzburg, Germany.
Endrich
S
S
Beier
D
D
Moran
A P
AP
Burek
C J
CJ
Rosenwald
A
A
Rieckmann
P
P
Müller-Hermelink
H-K
HK
Eck
M
M
D002460:Cell Line; D004847:Epithelial Cells / Q000276:immunology; D005753:Gastric Mucosa / Q000276:immunology*; D005756:Gastritis / Q000276:immunology / Q000382:microbiology; D015870:Gene Expression / Q000276:immunology; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori; D006801:Humans; D007113:Immunity, Innate; D016209:Interleukin-8 / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D000073871:Triggering Receptor Expressed on Myeloid Cells-1; D015854:Up-Regulation / Q000276:immunology
D016209:Interleukin-8; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; C408842:TREM1 protein, human; D000073871:Triggering Receptor Expressed on Myeloid Cells-1