Transient receptor potential vanilloid 4 (TRPV4) silencing in Helicobacter pylori-infected human gastric epithelium.
BACKGROUND
Helicobacter pylori (HP) infection induces methylation silencing of specific genes in gastric epithelium. Various stimuli activate the nonselective cation channel TRPV4, which is expressed in gastric epithelium where it detects mechanical stimuli and promotes ATP release. As CpG islands in TRPV4 are methylated in HP-infected gastric epithelium, we evaluated HP infection-dependent changes in TRPV4 expression in gastric epithelium.


METHODS
Human gastric biopsy samples, a human gastric cancer cell line (AGS), and a normal gastric epithelial cell line (GES-1) were used to detect TRPV4 mRNA and protein expression by RT-PCR and Western blotting, respectively. Ca2+imaging was used to evaluate TRPV4 ion channel activity. TRPV4 methylation status was assessed by methylation-specific PCR (MSP). ATP release was measured by a luciferin-luciferase assay.


RESULTS
TRPV4 mRNA and protein were detected in human gastric biopsy samples and in GES-1 cells. MSP and demethylation assays showed TRPV4 methylation silencing in AGS cells. HP coculture directly induced methylation silencing of TRPV4 in GES-1 cells. In human samples, HP infection was associated with TRPV4 methylation silencing that recovered after HP eradication in a time-dependent manner.


CONCLUSIONS
HP infection-dependent DNA methylation suppressed TRPV4 expression in human gastric epithelia, suggesting that TRPV4 methylation may be involved in HP-associated dyspepsia.
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.|Center for Medical Education and Career Development, University of Toyama, Toyama, Japan.
Hiroshi
H
Mihara
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Nobuhiro
N
Suzuki
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.|Department of Biological and Biomedical Sciences, Faculty of Health Sciences, The Aga Khan University, Karachi, Pakistan.
Jibran Sualeh
JS
Muhammad
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Sohachi
S
Nanjo
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Takayuki
T
Ando
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Haruka
H
Fujinami
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Shinya
S
Kajiura
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Ayumu
A
Hosokawa
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Toshiro
T
Sugiyama
D000255:Adenosine Triphosphate / Q000032:analysis; D000328:Adult; D000368:Aged; D001706:Biopsy; D015153:Blotting, Western; D002118:Calcium / Q000032:analysis; D002460:Cell Line; D019175:DNA Methylation; D004848:Epithelium / Q000382:microbiology* / Q000502:physiology*; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000502:physiology; D020869:Gene Expression Profiling; D020868:Gene Silencing; D016480:Helicobacter pylori / Q000254:growth & development*; D054884:Host-Pathogen Interactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D060888:Real-Time Polymerase Chain Reaction; D050916:TRPV Cation Channels / Q000096:biosynthesis* / Q000235:genetics
D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; D000255:Adenosine Triphosphate; D002118:Calcium

Helicobacter pylori
; TRPV4; gastric epithelium; methylation silencing; transient receptor potential vanilloid 4
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