title: Serum amyloid A1 secreted from UV-irradiated keratinocytes induces matrix metalloproteinase-1 in fibroblasts through toll-like receptor 4.
abstract: Ultraviolet (UV) irradiation on skin triggers photoageing-related phenotypes such as formation of wrinkles. UV ray upregulates matrix metalloproteinase-1 (MMP-1), which in turn degrades extracellular matrix proteins, mostly collagens. Serum amyloid A1 (SAA1) is an acute-phase protein of which plasma concentration increases in response to inflammation. Although the expression of SAA1 in the skin was reported, its function in the skin is yet to be studied. In this research, we found that the expression of SAA1 was increased in acute UV-irradiated buttock skin and photoaged forearm skin in vivo. UV irradiation also increased SAA1 in normal human epidermal keratinocytes (NHEK), and treatment of recombinant human SAA1 (rhSAA1) induced MMP-1 in normal human dermal fibroblasts (NHDF) but not in NHEK. Next, we demonstrated that NHDF treated with UV-irradiated keratinocyte-conditioned media showed the increased MMP-1 expression; however, this increase of MMP-1 in NHDF was inhibited by knockdown of SAA1 in NHEK. In addition, knockdown of Toll-like receptor 4 (TLR4) inhibited rhSAA1-induced MMP-1 expression in NHDF. Taken together, our data showed that UV-induced SAA1 production in NHEK, and this secreted SAA1 induced MMP-1 expression in NHDF in a paracrine manner through TLR4 signalling pathway. Therefore, our results suggest that SAA1 can be a potential mediator for UV-induced MMP-1 expression in human skin.
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sangbum
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Seon-Pil
authors.initials: SP
authors.lastname: Jin
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Jang-Hee
authors.initials: JH
authors.lastname: Oh
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Seo
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Chi-Hyun
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University Boramae Hospital, Seoul, Republic of Korea.
authors.forename: Hyun-Sun
authors.initials: HS
authors.lastname: Yoon
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Dong Hun
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea.|Institute on Aging, Seoul National University, Seoul, Republic of Korea.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Chung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005347:Fibroblasts / Q000378:metabolism*; D064368:Healthy Volunteers; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D008875:Middle Aged; D000685:Serum Amyloid A Protein / Q000378:metabolism*; D015398:Signal Transduction; D015595:Skin Aging / Q000528:radiation effects*; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: C521404:SAA1 protein, human; D000685:Serum Amyloid A Protein; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1
keywords: Toll-like receptor 4; matrix metalloproteinase-1; photoageing; serum amyloid A1; ultraviolet