{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T12:07:43Z","timestamp":1785154063035,"version":"3.55.0"},"reference-count":40,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T00:00:00Z","timestamp":1785110400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"departmental research funds"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Targeted phototherapy using 308-nm excimer light (EL-308) is widely employed to treat localized skin diseases, such as psoriasis and vitiligo. Although its immunomodulatory effects are well established, tissue-level epidermal responses to EL-308 in human skin explants have not been fully characterized in a controlled ex vivo setting. Therefore, the present study examined dose- and time-dependent changes in keratinocyte proliferation, apoptosis, and differentiation markers in a human organ-cultured skin model without systemic immune inputs (i.e., without circulation-dependent immune-cell recruitment). Human organ-cultured skin samples were irradiated with EL-308 at 300, 400, or 600 mJ\/cm2 and analyzed on days 2, 5, and 7 using immunohistochemical markers, including Ki-67, TUNEL, CK10, CK16, involucrin, and integrin \u03b21. RNA sequencing was performed 24 h after irradiation with 600 mJ\/cm2, followed by KEGG and GO enrichment analyses. EL-308 exposure was associated with dose- and time-dependent changes in Ki-67 and TUNEL labeling and with altered expression of differentiation-related markers (integrin \u03b21, CK16, CK10, and involucrin). Transcriptomic analyses revealed enrichment of metabolic and epidermis-related gene sets, including keratinization and epidermal development terms, consistent with a tissue-level response to UVB exposure. These findings provide descriptive data on epidermal marker dynamics and associated transcriptional programs after EL-308 irradiation in human organ-cultured skin and may inform future studies designed to evaluate early damage markers and functional outcomes.<\/jats:p>","DOI":"10.3390\/ijms27156698","type":"journal-article","created":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T11:54:26Z","timestamp":1785153266000},"page":"6698","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Direct Effects of 308-nm Excimer Light on Keratinocyte Proliferation and Differentiation in Human Organ-Cultured Skin"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6475-0586","authenticated-orcid":false,"given":"Ayaka","family":"Okazaki","sequence":"first","affiliation":[{"name":"Department of Dermatology, Graduate School of Medicine, Osaka City University, Osaka 5458585, Japan"},{"name":"Department of Dermatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka 5458585, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6930-5521","authenticated-orcid":false,"given":"Hisayoshi","family":"Imanishi","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka 5458585, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-6925-089X","authenticated-orcid":false,"given":"Hiroyuki","family":"Kunimoto","sequence":"additional","affiliation":[{"name":"Department of Immunology, Graduate School of Medicine, Osaka Metropolitan University, Osaka 5458585, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daisuke","family":"Tsuruta","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka 5458585, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1016\/j.jaad.2020.04.095","article-title":"Role of phototherapy in the era of biologics","volume":"84","author":"Torres","year":"2021","journal-title":"J. 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