title: Age-related disruption of autophagy in dermal fibroblasts modulates extracellular matrix components.
abstract: Autophagy is an intracellular degradative system that is believed to be involved in the aging process. The contribution of autophagy to age-related changes in the human skin is unclear. In this study, we examined the relationship between autophagy and skin aging. Transmission electron microscopy and immunofluorescence microscopy analyses of skin tissue and cultured dermal fibroblasts derived from women of different ages revealed an increase in the number of nascent double-membrane autophagosomes with age. Western blot analysis showed that the amount of LC3-II, a form associated with autophagic vacuolar membranes, was significantly increased in aged dermal fibroblasts compared with that in young dermal fibroblasts. Aged dermal fibroblasts were minimally affected by inhibition of autophagic activity. Although lipofuscin autofluorescence was elevated in aged dermal fibroblasts, the expression of Beclin-1 and Atg5-genes essential for autophagosome formation-was similar between young and aged dermal fibroblasts, suggesting that the increase of autophagosomes in aged dermal fibroblasts was due to impaired autophagic flux rather than an increase in autophagosome formation. Treatment of young dermal fibroblasts with lysosomal protease inhibitors, which mimic the condition of aged dermal fibroblasts with reduced autophagic activity, altered the fibroblast content of type I procollagen, hyaluronan and elastin, and caused a breakdown of collagen fibrils. Collectively, these findings suggest that the autophagy pathway is impaired in aged dermal fibroblasts, which leads to deterioration of dermal integrity and skin fragility.
authors.affiliation: Skin Research Department, POLA Chemical Industries, Inc., Yokohama, Japan; Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Tashiro
authors.affiliation: Skin Research Department, POLA Chemical Industries, Inc., Yokohama, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shishido
authors.affiliation: Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Organelle Homeostasis Research Center, Kyushu University, Fukuoka, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Hirota
authors.affiliation: Skin Research Department, POLA Chemical Industries, Inc., Yokohama, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Yo
authors.affiliation: Skin Research Department, POLA Chemical Industries, Inc., Yokohama, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Gomi
authors.affiliation: Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Organelle Homeostasis Research Center, Kyushu University, Fukuoka, Japan. Electronic address: tanakay@bioc.phar.kyushu-u.ac.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D001343:Autophagy; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000502:physiology*; D005260:Female; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008875:Middle Aged; D010588:Phagosomes / Q000502:physiology; D046988:Proteasome Endopeptidase Complex / Q000502:physiology; D012867:Skin / Q000166:cytology*; D015595:Skin Aging
chemical_list: C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D020781:Matrix Metalloproteinase 1; D046988:Proteasome Endopeptidase Complex
keywords: Autophagosome; Autophagy; CMA; Dermal fibroblast; Extracellular matrix; LAMP-2A; LC3; MMP-1; chaperone-mediated autophagy; leu; leupeptin; lysosome-associated receptor protein type 2A; matrix metalloproteinase-1; microtubule-associated protein 1 light chain 3; pep; pepstatin A