{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T02:45:51Z","timestamp":1788576351113,"version":"build-2803163510"},"reference-count":44,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2020,6,5]],"date-time":"2020-06-05T00:00:00Z","timestamp":1591315200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005006","name":"Asan Institute for Life Sciences, Asan Medical Center","doi-asserted-by":"publisher","award":["2019-415"],"award-info":[{"award-number":["2019-415"]}],"id":[{"id":"10.13039\/501100005006","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Epidermal keratinocytes are considered as the most important neighboring cells that modify melanogenesis. Our previous study used microarray to show that guanine deaminase (GDA) gene expression is highly increased in melasma lesions. Hence, we investigated the role of GDA in skin pigmentation. We examined GDA expression in post-inflammatory hyperpigmentation (PIH) lesions, diagnosed as Riehl\u2019s melanosis. We further investigated the possible role of keratinocyte-derived GDA in melanogenesis by quantitative PCR, immunofluorescence staining, small interfering RNA-based GDA knockdown, and adenovirus-mediated GDA overexpression. We found higher GDA positivity in the hyperpigmentary lesional epidermis than in the perilesional epidermis. Both UVB irradiation and stem cell factor (SCF) plus endothelin-1 (ET-1) were used, which are well-known melanogenic stimuli upregulating GDA expression in both keratinocyte culture alone and keratinocyte and melanocyte coculture. GDA knockdown downregulated melanin content, while GDA overexpression promoted melanogenesis in the coculture. When melanocytes were treated with UVB-exposed keratinocyte-conditioned media, the melanin content was increased. Also, GDA knockdown lowered SCF and ET-1 expression levels in keratinocytes. GDA in epidermal keratinocytes may promote melanogenesis by upregulating SCF and ET-1, suggesting its role in skin hyperpigmentary disorders.<\/jats:p>","DOI":"10.3390\/molecules25112637","type":"journal-article","created":{"date-parts":[[2020,6,9]],"date-time":"2020-06-09T08:49:11Z","timestamp":1591692551000},"page":"2637","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Guanine Deaminase in Human Epidermal Keratinocytes Contributes to Skin Pigmentation"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3432-8306","authenticated-orcid":false,"given":"Joon Min","family":"Jung","sequence":"first","affiliation":[{"name":"Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tai Kyung","family":"Noh","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soo Youn","family":"Jo","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Su Yeon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6268-5223","authenticated-orcid":false,"given":"Youngsup","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Young-Hoon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sung Eun","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1111\/bjd.15651","article-title":"Paracrine regulation of melanogenesis","volume":"178","author":"Yuan","year":"2018","journal-title":"Br. 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