title: Down-regulation of a forkhead transcription factor, FOXO3a, accelerates cellular senescence in human dermal fibroblasts.
abstract: The signaling pathway of insulin/insulin-like growth factor/phosphatidylinositol-3 kinase/Akt/forkhead transcription factors is known to control life span and senescence in organisms ranging from yeast to mice. The FOXO family of forkhead transcription factors, FOXO1, FOXO3a, and FOXO4, play a critical role in this signal transduction pathway. However, the impact of FOXO3a activation on life span of primary cultured human dermal fibroblasts (HDFs) is unknown. To investigate the role of FOXO3a in the regulation of cellular senescence, we prepared FOXO3a-siRNA stable HDFs. We found that the down-regulation of FOXO3a RNA and protein in HDFs induced many senescent phenotypes, including changes in cell morphology, increases in population doubling times, senescence-associated beta-galactosidase staining and the cellular reactive oxygen species, and up-regulation of p53/p21 protein expression. Our data provide evidence of the key role of FOXO3a transcription factor as a mediator of cellular senescence in HDFs, and suggest that the mechanism of senescence is conserved in HDFs.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, 317-1 Daemyung-Dong, Daegu 705-717, Republic of Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kyoung Kim
authors.forename: Yu
authors.initials: Y
authors.lastname: Kyoung Kim
authors.forename: In-Hwan
authors.initials: IH
authors.lastname: Song
authors.forename: Suk-Hwan
authors.initials: SH
authors.lastname: Baek
authors.forename: Seung-Rock
authors.initials: SR
authors.lastname: Lee
authors.forename: Jung
authors.initials: J
authors.lastname: Hye Kim
authors.forename: Jae-Ryong
authors.initials: JR
authors.lastname: Kim
mesh_terms: D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D015536:Down-Regulation; D005347:Fibroblasts / Q000502:physiology*; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D006801:Humans; D010641:Phenotype; D034741:RNA, Small Interfering / Q000096:biosynthesis; D012867:Skin / Q000166:cytology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D034741:RNA, Small Interfering; D014157:Transcription Factors