https://ir.ymlib.yonsei.ac.kr/handle/22282913/168778 2026-07-06T12:46:37Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/212641 Title: Particulate matter exposure induces maternal scalp hair loss after birth in C57/B6 mouse via alteration of inflammatory and apoptotic pathways Authors: Jung, Gee Soo; Lee, Min Jung; Im, Wooseok; Park, Hyemin; Lee, Inha; Lee, Jae Hoon; Ku, Hyeno Ho; Lee, Sang Eun; Cho, SiHyun; Choi, Young Sik Abstract: PM 2.5 exposure is associated with a variety of health effects, including effects on the reproductive and skin. However, the relationship between PM2.5 exposure and postpartum hair loss has not been investigated. In this study, we evaluated the effect of PM2.5 exposure on hair loss after birth in mouse model and analyzed possible associated molecular changes. Female mice were exposed to PM2.5 using nasal inhalation method. After 4 weeks, mating tests were conducted and postpartum scalp tissues from PM2.5-exposed mice and those without exposure were harvested and analyzed. Then, human immortalized keratinocyte cell line (HaCaT cells) and fibroblasts were cultured and treated with PM2.5 for 24 hours. Changes in the inflammatory, apoptotic, fibrotic, and proliferative pathways were evaluated. Postpartum scalp hair loss was evident in PM2.5 exposed mice group with significant morphological changes in scalp tissues. The expression levels of IL-6, IL-1 beta, TNF-alpha and p-NF-kappa B, Caspase-3, the BAX/Bcl-2 ratio, COL1A1, MMP2 and MMP9 were significantly higher in the PM2.5-exposed group than in the control group. The expressions of were elevated in PM2.5 exposed group than the controls, where the expressions of PR-B, PR-A, CD34 and K15 were significantly lower in the exposed group. Histologic analysis showed that PM2.5 exposed postpartum scalp showed thickened stratum corneum, migration of hair follicles deeper into the dermis with a decrease in the number of hair follicles. Increased collagen density in the dermis was also observed in scalp tissues from the PM2.5-exposed group. In vitro experiments showed that PM2.5 exposure significantly increased expressions of p-NF-kappa B/NF-kappa B, p-c-jun/c-jun, p-p53/p53, p27, Caspase-3 and BAX/Bcl-2, where p-ERK/ERK and VEGF expressions were significantly reduced in HaCaT cells and fibroblasts. These findings suggest that PM2.5 exposure induces postpartum hair loss via alterations of inflammatory and apoptotic pathways. PM2.5 exposure induces significant downregulation of progesterone receptors and reduces the hair follicle stem cells (HFSCs) population, which may contribute to the exacerbation of postpartum hair loss. 2026-05-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/211973 Title: mRNA-based allergen-specific immunotherapy to modulate type 2 airway inflammation Authors: Zhang, KeLun; Park, Chang Ook 2026-04-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/212032 Title: Trends in Contact Sensitization Among Korean Patients: A Multicenter 6-Year Retrospective Patch Test Study Authors: Kim, Myoung Shin; Kim, Ho Sung; Park, Eun Joo; Kim, Hye One; Lee, Jungsoo; Lee, Dong Hun; Jung, Joon Min; Chang, Sung Eun; Jung, Hye Jung; Ko, Joo Yeon; Jue, Mihn-Sook; Choi, Sun Young; Jeon, Jiehyun; Kim, Myung Hwa; Cheong, Seung Hyun; Choi, Young-Jun; Lee, Sang Eun; Kim, Ki-Ho; Lee, Ga-Young Abstract: Background Allergic contact dermatitis is influenced by demographic factors. Updated epidemiologic data are needed to optimise patch test panels and preventive strategies.Objectives To evaluate trends and determinants of allergen sensitization in Korean patients undergoing patch testing.Methods Retrospective analysis of patch test records of 2271 patients at 15 university hospitals in Korea between 2019 and 2024. Patch test reactions were interpreted according to International Contact Dermatitis Research Group criteria. Association with age, sex, and body site was assessed.Results Overall, 57.1% of patients exhibited at least one positive reaction; among patients with positive reactions, 48.7% exhibited multi-sensitizations. Most frequent positive patch reactions were to nickel (29.0%), cobalt (18.2%), and chromium (8.2%). Women were more frequently sensitised to nickel and cobalt. Sensitization to fragrance mix I, Myroxylon pereirae resin, and p-phenylenediamine increased with age, whereas sensitization to thimerosal decreased. Facial involvement was associated with higher sensitization to lanolin alcohol; hand involvement with 2-mercaptobenzothiazole, colophonium, 4-tert-butylphenol formaldehyde resin and thimerosal; and scalp involvement with mercapto mix, 4-tert-butylphenol formaldehyde resin, p-phenylenediamine, and lanolin alcohol.Conclusions Metals, particularly nickel and cobalt, remain the predominant sensitizers in Korea. Age, sex, and localization differences underscore the need for targeted screening and public health strategies. 2026-04-01T00:00:00Z https://ir.ymlib.yonsei.ac.kr/handle/22282913/212594 Title: Unanchored by two hits: interferon-γ and mechanical stress synergize to undermine melanocyte adhesion and promote vitiligo Authors: Lee, Eun Jung; Kwon, Il Joo; Kim, Ji Young; Park, Seohyun; Han, Hui-ting; Hwang, Shinwon; Bae, Yu Jeong; Kim, A. Ram; Alqahtani, Jamal Mohammed; Kim, Dong Hyun; Lee, Jinu; Lee, Si-Hyung; Oh, Sang Ho; 권일주 Abstract: Background Vitiligo is a chronic depigmentation disorder caused by selective melanocyte loss. Autoreactive CD8+ T cells are known contributors, but impaired melanocyte-keratinocyte adhesion due to E-cadherin dysfunction has also been implicated.Objectives To identify the key adhesion molecules mediating melanocyte-basement membrane interactions and to investigate their modulation in response to vitiligo-associated factors, including interferon (IFN)-gamma and mechanical stress.Methods Primary human epidermal melanocytes and ex vivo human skin tissues were exposed to IFN-gamma and mechanical stress. To identify key molecules involved in melanocyte adhesion, we integrated RNA sequencing data from prior studies with antibody array profiling. The involvement of focal adhesion-associated proteins in melanocyte-basement membrane attachment was further assessed by confocal imaging of skin from patients with vitiligo, revealing a reduction in these molecules.Results Exposure to IFN-gamma and mechanical stress reduced focal adhesion kinase (FAK) and integrin beta 1 (ITG beta 1) expression in melanocytes and ex vivo human skin, increasing melanocyte detachment. Both molecules were also decreased in basal keratinocytes and melanocytes from the skin of patients with vitiligo compared with healthy controls. Pretreatment with the Janus kinase inhibitor baricitinib, used in vitiligo therapy, reduced melanocyte detachment through a cathepsin L (CTSL)-dependent mechanism.Conclusions IFN-gamma and mechanical stress contribute to melanocyte detachment from the basement membrane via CTSL, FAK and ITG beta 1 regulation. These findings highlight the importance of melanocyte-basement membrane adhesion in vitiligo pathogenesis and offer insight into the Koebner phenomenon in disease progression. Vitiligo is a persistent condition that affects the pigmentation (colour) of skin. Areas of skin become very pale or white. This is caused by the loss of skin cells called melanocytes. These cells produce a pigment called melanin. Melanin is responsible for skin, hair and eye colour.In vitiligo, melanocytes are mistakenly attacked by the body's own immune system. Melanocytes can be destroyed altogether or damaged, so that they no longer function correctly.We studied whether melanocyte damage is caused by a molecule called 'interferon gamma'. We combined this molecule with mechanical stress. Mechanical stress involved repeatedly stretching the skin cells in the lab. We found that the combination of interferon gamma and mechanical stress reduced the ability of melanocytes to work properly. The cells also produced fewer of the molecules they need to attach to skin ('attachment molecules'). When this was reversed, the melanocytes were able to attach properly.In conclusion, interferon gamma and mechanical stress may be important in vitiligo. This finding could help us develop new treatment strategies for vitiligo. Interferon-gamma and mechanical stress reduce focal adhesion between melanocytes and the basement membrane. This finding not only advances our understanding of vitiligo pathogenesis, but also highlights a novel therapeutic avenue and provides mechanistic insight into the Koebner phenomenon. 2026-04-01T00:00:00Z