title: Genetic evidence for a protective role of heat shock factor 1 against irritant-induced gastric lesions.
abstract: Gastric lesions result from an imbalance between aggressive and defensive factors. Indirect lines of evidence suggest that heat shock proteins (HSPs) induced by various aggressive factors provide a major protective mechanism. In this study, we compared gastric ulcerogenic response in wild-type mice and in those lacking heat shock factor 1 (HSF1), a transcription factor for hsp genes. The severity of gastric lesions induced by ethanol or hydrochloric acid was worsened in HSF1-null mice. Immunoblotting, real-time reverse transcription-polymerase chain reaction, immunohistochemical analysis, and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay revealed that the ethanol administration up-regulated gastric mucosal HSPs, in particular HSP70, in an HSF1-dependent manner, and more apoptotic cells were observed in the gastric mucosa of HSF1-null mice than in wild-type mice. In contrast, other parameters governing the gastric ulcerogenic response, including gastric acid secretion, gastric mucosal blood flow, and prostaglandin E(2) levels, were not significantly affected by the absence of the hsf1 gene. Geranylgeranylacetone (GGA), a clinically used antiulcer drug with HSP-inducing activity, suppressed ethanol-induced gastric lesions in wild-type mice but not in heat shock factor 1 (HSF1)-null mice. The results suggest that the aggravation of irritant-induced gastric lesions in HSF1-null mice is due to their inability to up-regulate HSPs, leading to apoptosis. It is also suggested that the HSP-inducing activity of GGA contributes to the drug's antiulcer activity. This study provides direct genetic evidence that HSPs, after their HSF1-dependent up-regulation, confer gastric protection against the irritant-induced lesions.
authors.affiliation: Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan.
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Tanaka
authors.forename: Shinji
authors.initials: S
authors.lastname: Tsutsumi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Arai
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hoshino
authors.forename: Keitarou
authors.initials: K
authors.lastname: Suzuki
authors.forename: Eiichi
authors.initials: E
authors.lastname: Takaki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ito
authors.forename: Koji
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Akira
authors.initials: A
authors.lastname: Nakai
authors.forename: Tohru
authors.initials: T
authors.lastname: Mizushima
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics*; D004224:Diterpenes / Q000494:pharmacology / Q000627:therapeutic use; D000431:Ethanol / Q000494:pharmacology; D005753:Gastric Mucosa / Q000473:pathology; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000032:analysis / Q000187:drug effects; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D013276:Stomach Ulcer / Q000139:chemically induced; D014157:Transcription Factors / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D004268:DNA-Binding Proteins; D004224:Diterpenes; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C490017:Hsf1 protein, mouse; D014157:Transcription Factors; D000431:Ethanol; D006851:Hydrochloric Acid; C031049:geranylgeranylacetone