Abstract Booklet Thank you to those who submitted abstracts to the SID 2020 Annual Meeting. With the cancellation of the SID Annual Meeting originally scheduled for May 13 ‐ 16, 2020, in Scottsdale, the meeting has been converted to provide select content in a virtual setting. Abstract presenting authors were contacted to confirm their intent to publish their accepted abstract. On the following pages is a listing of the abstracts that have confirmed publication (as of May 8, 2020). Abstracts will be published in the July 2020 Supplement of the JID. Abstract Table of Contents 04 Adaptive and Auto-Immunity Abstracts 001 - 101 20 Carcinogenesis and Cancer Genetics Abstracts 103 – 155 31 Cell-Cell Interactions in the Skin * Singe-Cell Transcriptomics and Cell-Cell Interactions in the Skin Abstracts 157 - 192 37 Epidermal Structure and Barrier Function Abstracts 195 – 256 48 Genetic Disease, Gene Regulation, and Gene Therapy Abstracts 257 – 307 59 Innate Immunity, Microbiology, and Microbiome Abstracts 309 –365 70 Patient Population Research Abstracts 366 – 486 98 Patient-Targeted Research Abstracts 487 – 557 113 Pharmacology and Drug Development Abstracts 559– 615 124 Photobiology Abstracts 616 – 645 129 Pigmentation and Melanoma Abstracts 646 – 710 140 Skin of Color Abstracts 712 – 743 146 Skin, Appendages, and Stem Cell Biology Abstracts 744 – 789 152 Tissue Regeneration and Wound Healing Abstracts 791 – 832 159 Translational Studies Abstracts 833 - 913 177 Late-Breaking Abstracts 194 Keywords *Category Name Amended (February 2020) Adaptive and Auto-Immunity 001 Lymph node-fibroblastic reticular cells regulate differentiation of CD4 T cells through CD25 D. Kim1, T. Kim1, S. Lee1, K. Shin1, 2, 3 1Biomedical Research Center, KAIST Institute for the Bio-Century, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea (the Republic of), 2Department of Dermatology, Pusan National University Yangsan Hospital, Yangsan, Korea (the Republic of), 3Department of Dermatology, Pusan National University Hospital, Busan, Korea (the Republic of) Lymph node-fibroblastic reticular cells (LN-FRCs) not only provide functional structure to LNs, they also play an important role in the interaction between T cells and antigen-presenting cells. However, their role in the differentiation of naive CD4 T cells remains unclear. Here, we report that of the three distinct subunits of the IL-2 receptor (IL-2R), LN-FRCs express IL-2R alpha chain, CD25, only. LNFRCs provide naive CD4 T cells with IL-2 in a trans-presentation manner through CD25, thereby facilitating early IL-2-mediated signaling and regulating CD4 T cell differentiation. CD25-deficient FRCs exhibited attenuated phosphorylation of STAT5 due to diminished IL-2 signaling in naive CD4 T cells. CD25-deficient FRCs promoted Th17 cell differentiation and induced expression of genes involved in Th17-mediated immune responses. Hence, Th17 cell-mediated inflammatory disease was markedly enhanced in mice lacking CD25 on FRCs. Therefore, our results suggest that CD25 expression on FRCs regulates CD4 T cell differentiation by modulating early IL-2-mediated signaling of neighboring, naive CD4 T cells, and thus influences the overall character of the immune response. 003 Dextran-based acitretin nanoparticle ameliorates imiquimod-induced psoriasis-like skin inflammation J. Lan1, H. Du1, Y. Li2, Y. Zhang1, J. Tao1 1Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China., Wuhan, Hubei, China, 2School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China Acitretin (Act) is one of the first-line treatments for moderate to severe psoriasis, while the systemic side effects caused by Act greatly restrict its clinical application. Herein, we developed the Dextran-based Act nanoparticles (DANPs) and proved their enhanced therapeutic effects in the mice models of imiquimod-induced psoriasis. Dextran and Act molecules were linked by ester bonds to form a spherical nanostructure, and extra free Act molecules were encapsulated. When injected in vivo, free Act will be soon released while the slow dissociation of linked Act will help keep an effective blood concentration for a long time. We treated the psoriasis mice with dextran, acitretin and DANPs by daily intraperitoneal injection for 6 days. Then, the skin lesions were evaluated by Psoriasis Area and Severity Index (PASI) scoring, H&E staining and immunohistochemical staining. Our results in vivo showed a significant reduction of PASI score and epidermal thickness after DANPs (1mg/kg/day) treatment , Ki-67 expression in keratinocytes also decreased (P<0.01). While the psoriasis mice treated with acitretin (1mg/kg/day) or dextran (1mg/kg/day) showed no obvious improvement in skin inflammation. In vitro study showed that the uptake of DANPs by HaCaT cells increased gradually with incubation time and DANPs concentration, reaching a maximum at 4h. Furthermore, we compared the in vitro effect of dextran, acitretin and DANPs on HaCaT cells. Compared to dextran and acitretin groups, DANPs showed more significant cytotoxicity to HaCaT cells (P<0.01) and induced more significant apoptosis of HaCaT cells (P<0.01). Overall, our work provided a new choice for psoriasis systemic treatment, with enhanced therapeutic efficiency and reduced the side effects. 004 Localized administration of methotrexate regulates psoriasis-like skin inflammation and protects from secondary sensitization at a distant site H. Du1, J. Lan1, P. Liu2, J. Zhu2, J. Tao1 1Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China, 2School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China Methotrexate (MTX), a first-line systemic agent for the therapy of psoriasis, is often associated with adverse effects. Localized transdermal delivery of MTX using dissolving microneedles (MNs) was demonstrated to be both more efficacious and better tolerated than oral administration in our previous work. This study aims to elucidate the detailed therapeutic mechanism of MTX-loaded MNs and to explore whether topical MTX treatment can affect the formation of skin lesion at distant parts of the body while attenuating local inflammation. In vitro experiments suggested that MTX effectively reduced the production of proinflammatory cytokines in IL-17A-treated HaCaT cells and imiquimod (IMQ)-treated mouse bone marrow-derived dendritic cells (P<0.001). Psoriasiform dermatitis was then induced on the left ear skin of mice by topical IMQ application. Histological and immunohistochemical (Ki67, CD11c and CD3) examinations showed much milder epidermal hyperplasia and inflammatory infiltration upon MTX-loaded MNs treatment. We also found that MTX-loaded MNs substantially downregulated leukocyte chemotaxis and migration, T cell proliferation and activation as well as the development and keratinization of epidermis by RNA sequencing. Additionally, flow cytometric analysis indicated that the accumulation of IL-17A-producing Vγ4+ γδT cells in MNs-treated left ear skin and the draining lymph nodes were both significantly inhibited (P<0.001). Furthermore, the subsequent generation of psoriatic phenotype on the right ears by IMQ rechallenge was markedly restrained compared with untreated mice. In conclusion, MTX-loaded MNs can not only ameliorate local skin inflammation by regulating immune and stromal components but also show a concomitant antipsoriatic effect against recurrent immune disorders at a distant site, emerging as a potential alternative topical treatment for psoriasis. 005 Respiratory activity in psoriatic circulating T cells predicts the efficacy of apremilast H. Koguchi-Yoshioka1, 2, R. Watanabe2, Y. Matsumura2, T. Matsuzaka3, H. Shimano3, M. Fujimoto1, 2 1Dermatology , Osaka University, Suita, Osaka, Japan, 2Dermatology, University of Tsukuba, Tsukuba, Japan, 3Internal Medicine, Metabolism and Endocrinology, University of Tsukuba, Tsukuba, Japan While psoriasis is a Th17-mediated disease related with metabolic skews, the relation between T-cell reactivity and cellular metabolism has not been fully evaluated in psoriasis. In this research, the metabolic condition of blood T cells were evaluated in 35 psoriatic patients by use of an extracellular flux analyzer. The impact of apremilast on cellular metabolic condition was also investigated in total 71 patients with psoriasis both in vivo and in vitro. The oxygen consumption rate (OCR) was significantly higher in blood T cells of psoriasis patients compared to healthy controls (p = 0.0014), and the patients with higher OCR achieved higher % PASI improvement by apremilast (r = 0.6182, p = 0.0478). The increase of cAMP is regarded to upregulate the mitochondrial activity via activation of protein kinase A. However, apremilast paradoxically decreased the T-cell OCR (p = 0.0322). The decrease of OCR was presumably attributed to the reactive oxygen species (ROS) because the cellular ROS level was higher in psoriatic blood T cells compared to healthy controls (p = 0.0022) and the in vitro inhibition or elimination of ROS led to the decline of cellular OCR. The superoxide dismutase was also upregulated by co-culturing the psoriatic blood T cells with apremilast (p = 0.0313). Of note, the T-cell OCR showed a mild correlation with the serum level of LDH in the patients with psoriasis (r = 0.3454, p = 0.0454), and the patients with