Serum amyloid A1 secreted from UV‐irradiated keratinocytes induces matrix metalloproteinase‐1 in fibroblasts through toll‐like receptor 4 |
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| Authors: | Sangbum Han Seon‐Pil Jin Jang‐Hee Oh Eun‐Young Seo Chi‐Hyun Park Hyun‐Sun Yoon Dong Hun Lee Jin Ho Chung |
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| Affiliation: | 1. Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea;2. Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea;3. Institute of Human‐Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea;4. Department of Dermatology, Seoul National University Boramae Hospital, Seoul, Republic of Korea;5. Institute on Aging, Seoul National University, Seoul, Republic of Korea |
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| 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. |
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| Keywords: | matrix metalloproteinase‐1 photoageing serum amyloid A1 Toll‐like receptor 4 ultraviolet |
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