title: Characterization of Skin Aging-Associated Secreted Proteins (SAASP) Produced by Dermal Fibroblasts Isolated from Intrinsically Aged Human Skin.
abstract: Most molecular hallmarks of cellular senescence have been identified in studies of cells aged in vitro by driving them into replicative or stress-induced senescence. Comparatively, less is known about the characteristic features of cells that have aged in vivo. Here we provide a systematic molecular analysis of normal human dermal fibroblasts (NHDFs) that were isolated from intrinsically aged human skin of young versus middle aged versus old donors. Intrinsically aged NHDFs in culture exhibited more frequently nuclear foci positive for p53 binding protein 1 and promyelocytic leukemia protein reminiscent of 'DNA segments with chromatin alterations reinforcing senescence (DNA-SCARS)'. Formation of such foci was neither accompanied by increased DNA double strand breaks, nor decreased cell viability, nor telomere shortening. However, it was associated with the development of a secretory phenotype, indicating incipient cell senescence. By quantitative analysis of the entire secretome present in conditioned cell culture supernatant, combined with a multiplex cytokine determination, we identified 998 proteins secreted by intrinsically aged NHDFs in culture. Seventy of these proteins exhibited an age-dependent secretion pattern and were accordingly denoted 'skin aging-associated secreted proteins (SAASP)'. Systematic comparison of SAASP with the classical senescence-associated secretory phenotype (SASP) revealed that matrix degradation as well as proinflammatory processes are common aspects of both conditions. However, secretion of 27 proteins involved in the biological processes of 'metabolism' and 'adherens junction interactions' was unique for NHDFs isolated from intrinsically aged skin. In conclusion, fibroblasts isolated from intrinsically aged skin exhibit some, but not all, molecular hallmarks of cellular senescence. Most importantly, they secrete a unique pattern of proteins that is distinct from the canonical SASP and might reflect specific processes of skin aging.
authors: Molecular Proteomics Laboratory, Heinrich-Heine-University, Düsseldorf, Germany; Biomedical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany.
authors: Daniel M
authors: DM
authors: Waldera Lupa
authors: Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany.
authors: Faiza
authors: F
authors: Kalfalah
authors: Hamamatsu Tissue Imaging and Analysis Center, BIOQUANT, Ruprecht-Karls-University, Heidelberg, Germany.
authors: Kai
authors: K
authors: Safferling
authors: German Cancer Research Centre, Heidelberg, Germany.
authors: Petra
authors: P
authors: Boukamp
authors: Molecular Proteomics Laboratory, Heinrich-Heine-University, Düsseldorf, Germany; Biomedical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany.
authors: Gereon
authors: G
authors: Poschmann
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany.
authors: Elena
authors: E
authors: Volpi
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany.
authors: Christine
authors: C
authors: Götz-Rösch
authors: L'Oréal Recherche, Clichy, Paris, France.
authors: Francoise
authors: F
authors: Bernerd
authors: Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany.
authors: Laura
authors: L
authors: Haag
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany.
authors: Ulrike
authors: U
authors: Huebenthal
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany.
authors: Ellen
authors: E
authors: Fritsche
authors: Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany.
authors: Fritz
authors: F
authors: Boege
authors: Hamamatsu Tissue Imaging and Analysis Center, BIOQUANT, Ruprecht-Karls-University, Heidelberg, Germany.
authors: Niels
authors: N
authors: Grabe
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany.
authors: Julia
authors: J
authors: Tigges
authors: Molecular Proteomics Laboratory, Heinrich-Heine-University, Düsseldorf, Germany; Biomedical Research Center (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany.
authors: Kai
authors: K
authors: Stühler
authors: IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Düsseldorf gGmbH, Düsseldorf, Germany; University of Düsseldorf, Medical Faculty, Deanery of Medicine, Düsseldorf, Germany. Electronic address: jean.krutmann@iuf-duesseldorf.de.
authors: Jean
authors: J
authors: Krutmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000235:genetics; D004247:DNA / Q000235:genetics; D020405:Dermis / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D010641:Phenotype; D011506:Proteins / Q000378:metabolism*; D012867:Skin / Q000378:metabolism / Q000473:pathology; D015595:Skin Aging / Q000235:genetics / Q000473:pathology*; D016615:Telomere / Q000235:genetics; D055815:Young Adult
chemical_list: D011506:Proteins; D004247:DNA