title: Differential regulation of Krüppel-like factor family transcription factor expression in neonatal rat cardiac myocytes: effects of endothelin-1, oxidative stress and cytokines.
abstract: Krüppel-like transcription factors (Klfs) modulate fundamental cell processes. Cardiac myocytes are terminally-differentiated, but hypertrophy in response to stimuli such as endothelin-1. H2O2 or cytokines promote myocyte apoptosis. Microarray studies of neonatal rat myocytes identified several Klfs as endothelin-1-responsive genes. We used quantitative PCR for further analysis of Klf expression in neonatal rat myocytes. In response to endothelin-1, Klf2 mRNA expression was rapidly increased ( approximately 9-fold; 15-30 min) with later increases in expression of Klf4 and Klf6 ( approximately 5-fold; 30-60 min). All were regulated as immediate early genes (cycloheximide did not inhibit the increases in expression). Klf5 expression was increased at 1-2 h ( approximately 13-fold) as a second phase response (cycloheximide inhibited the increase). These increases were transient and attenuated by U0126. H2O2 increased expression of Klf2, Klf4 and Klf6, but interleukin-1beta or tumor necrosis factor alpha downregulated Klf2 expression with no effect on Klf4 or Klf6. Of the Klfs which repress transcription, endothelin-1 rapidly downregulated expression of Klf3, Klf11 and Klf15. The dynamic regulation of expression of multiple Klf family members in cardiac myocytes suggests that, as a family, they are actively involved in regulating phenotypic responses (hypertrophy and apoptosis) to extracellular stimuli.
authors.affiliation: National Heart and Lung Institute (NHLI) Division, Faculty of Medicine, Imperial College London, Flowers Building (4th Floor), Armstrong Road, London SW7 2AZ, UK.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Cullingford
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Butler
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Marshall
authors.forename: El Li
authors.initials: el L
authors.lastname: Tham
authors.forename: Peter H
authors.initials: PH
authors.lastname: Sugden
authors.forename: Angela
authors.initials: A
authors.lastname: Clerk
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000494:pharmacology*; D005786:Gene Expression Regulation; D006861:Hydrogen Peroxide / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D019332:Endothelin-1; D053583:Interleukin-1beta; C000715469:Klf4 protein, rat; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D016877:Oxidants; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide