title: Noninvasive and quantitative live imaging reveals a potential stress-responsive enhancer in the failing heart.
abstract: Recent advances in genome analysis have enabled the identification of numerous distal enhancers that regulate gene expression in various conditions. However, the enhancers involved in pathological conditions are largely unknown because of the lack of in vivo quantitative assessment of enhancer activity in live animals. Here, we established a noninvasive and quantitative live imaging system for monitoring transcriptional activity and identified a novel stress-responsive enhancer of Nppa and Nppb, the most common markers of heart failure. The enhancer is a 650-bp fragment within 50 kb of the Nppa and Nppb loci. A chromosome conformation capture (3C) assay revealed that this distal enhancer directly interacts with the 5'-flanking regions of Nppa and Nppb. To monitor the enhancer activity in a live heart, we established an imaging system using the firefly luciferase reporter. Using this imaging system, we observed that the novel enhancer activated the reporter gene in pressure overload-induced failing hearts (failing hearts: 5.7±1.3-fold; sham-surgery hearts: 1.0±0.2-fold; P<0.001, repeated-measures ANOVA). This method will be particularly useful for identifying enhancers that function only during pathological conditions.
authors.affiliation: 1Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. asano@cardiology.med.osaka-u.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Asano
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Higo
authors.forename: Osamu
authors.initials: O
authors.lastname: Tsukamoto
authors.forename: Yi
authors.initials: Y
authors.lastname: Yan
authors.forename: Satoru
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuzaki
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Kioka
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Kato
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Uno
authors.forename: Masanori
authors.initials: M
authors.lastname: Asakura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asanuma
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Minamino
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Aburatani
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kitakaze
authors.forename: Issei
authors.initials: I
authors.lastname: Komuro
authors.forename: Seiji
authors.initials: S
authors.lastname: Takashima
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D006333:Heart Failure / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020097:Natriuretic Peptide, Brain / Q000235:genetics*; D020098:Natriuretic Peptide, C-Type / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; C431578:Nppa protein, mouse; D011498:Protein Precursors; D020097:Natriuretic Peptide, Brain; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor; D008156:Luciferases
keywords: in vivo assessment; natriuretic peptide; transcriptional regulation