Dermatology
Abstract
Integrative multiscale imaging bridges the gap between macroscopic organ structures and microscopic cellular processes, enabling holistic visualization of anatomy and function across scales. Photoacoustic imaging (PAI) leverages melanin’s potent contrast for label-free melanoma detection, yet its potential in lung imaging, challenged by air-tissue acoustic impedance mismatch, remains unexplored for melanoma lung metastases (MLMs). We used hierarchical multiscale PAI, transitioning from whole-body macroscale to localized mesoscale and single-cell-resolution microscale. PAI also guided photoablation interventions in the first and second near-infrared windows, requiring only 10.4 pg intracellular melanin/cell. Bioinformatic analysis of human MLM tissues revealed perturbed signaling pathways compared with normal skin and lung tissues, accounting for dysfunctional melanogenesis to enable label-free PAI with high sensitivity and specificity. Malignant MLM lesions in living mice, resected mouse lungs, and human lungs were delineated with margins closely conforming to histology. The high sensitivity allowed visualization of low-cellularity microsatellite foci down to a few tens of cell clusters, with sufficient penetration in the lungs of mice and Bama minipigs. The multiscale imaging methodology streamlines a theranostic workflow and specifically identifies MLM burden in a progressive, label-free manner, which may aid real-time tumor ablation in the future.
Authors
Wei Xing, Yujia Zhou, Katja Haedicke, Chenyixin Wang, Karla Ximena Vazquez-Prada, Hong Wu, Zhijun Lin, Chrysafis Andreou, Qize Zhang, Ke Shang, Ruoyang Hu, Moritz Kircher, Xingdong Ye, Jan Grimm, Jiang Yang
Abstract
Chemotherapy-induced alopecia (CIA) remains one of the most distressing adverse effects of cancer therapy. Yet, no therapy is available to selectively protect healthy hair follicles (HFs) and their epithelial stem cells (eHFSCs) from chemotherapy-induced damage without awarding potential survival benefits to cancer cells. Here, we report how human HFs can be protected against 2 lead CIA-inducing chemotherapeutics by inducing selective transient cell cycle arrest. Pretreating scalp HFs before chemotherapy exposure ex vivo with ALRN-6924, a clinical-stage “stapled peptide” drug that binds with high affinity to key endogenous inhibitors of p53, selectively activated p53 signaling only in cells with wild-type TP53 genotype and upregulated p21. This led to temporary cell cycle arrest in healthy tissues without protecting TP53-mutant cancer cells and mitigated chemotherapy-induced HF damage on multiple levels, including excessive hair matrix apoptosis, premature catagen, pigmentary abnormalities, “mitotic catastrophe,” and micronucleation. It also protected eHFSCs against DNA damage, apoptosis, and pathological epithelial-mesenchymal transition. Notably, even topically applied ALRN-6924 afforded relative chemotherapy protection ex vivo. These results provide proof of principle for a strategy to selectively protect rapidly proliferating healthy epithelial tissues and their stem cells in patients with TP53-mutant cancers, which promises to protect against acute and permanent CIA.
Authors
Jennifer Gherardini, Tara Samra, Tatiana Gomez-Gomez, Aysun Akhundlu, Samantha D. Verling, Kinga Linowiecka, Tongyu C. Wikramanayake, Ulrich Knie, Jose Rodríguez-Feliz, Ramtin Kassir, Wolfgang Funk, Reza P. Azar, D. Allen Annis, Manuel Aivado, Jérémy Chéret, Ralf Paus
Abstract
Neuropathic pain affects over 20 million people in the United States, and painful diabetic neuropathy (PDN), a common complication of diabetes, is among its most prevalent and treatment-resistant forms. Although PDN is characterized by nociceptor dysfunction, the upstream peripheral mechanisms remain incompletely understood. While dorsal root ganglion (DRG) nociceptor hyperexcitability is a hallmark of PDN, emerging evidence suggests that non-neuronal skin cells may modulate nociceptor function. Here, we investigated whether epidermal Langerhans cells (LCs) contribute to neuropathic pain in PDN through neuroimmune signaling. Using a clinically relevant high-fat diet (HFD) mouse model, transgenic LC ablation, behavioral assays, human skin biopsies, and single-cell RNA sequencing of epidermis and DRG, we found that LC density increased in male diabetic mice in parallel with mechanical allodynia. In human PDN skin, LCs exhibited increased volume and dendritic complexity correlating with diabetes duration. Genetic depletion of LCs prevented mechanical allodynia and spontaneous pain-like behavior in male, but not female, HFD mice, revealing a sex-dependent contribution. Single-cell and interactome analyses identified male-specific inflammatory LC programs, including upregulation of chemokine signaling pathways. Consistently, LC secretome profiling showed increased CCL2 release, and local CCR2 blockade reversed allodynia. These findings identify epidermal LCs as peripheral regulators of PDN pain and highlight sex-dependent chemokine-mediated neuron-immune communication at the skin-nerve interface.
Authors
Paola Pacifico, Dale George, Nirupa D. Jayaraj, Dongjun Ren, James S. Coy-Dibley, Abdelhak A. Belmadani, Sofia Veronesi, Mirna Andelic, Daniele Cartelli, Grazia Devigili, Raffaella Lombardi, Giuseppe Lauria Pinter, Amy S. Paller, Richard J. Miller, Daniela M. Menichella
Abstract
Lysine-specific demethylase 1 (LSD1; KDM1A) orchestrates context-dependent chromatin programs, yet its role in epithelial immunity remains largely unknown. Here, we identify LSD1 as a central brake on retinoid- and AP-1–driven enhancer activation in epidermis and demonstrate that its inhibition induces anti-tumor immunity. While epidermal LSD1 is required during development, acute loss or topical inhibition in adult skin is tolerated and triggers coordinated expression of retinoic acid signaling, lipid remodeling, and chemokine induction pathways. CUT&RUN profiling reveals that LSD1 occupies enhancer regions enriched for AP-1 motifs at retinoid metabolism, lipid homeostasis, and immune genes. LSD1 loss increases H3K4me1/2 and gene activation at these sites, licensing a poised AP-1–retinoid program. Single-cell spatial analyses show that discrete keratinocyte subsets initiate retinoid signaling to recruit dendritic cells and activate CD4+ T cell responses. Topical LSD1 inhibition suppresses cutaneous squamous cell carcinoma in two models while amplifying keratinocyte–immune crosstalk. Functional perturbations reveal that retinoid signaling partially contributes, whereas CD4+ T cells are essential for tumor control. These findings define LSD1 as a master repressor of epithelial immune competence and nominate LSD1 inhibition as a therapeutic strategy to activate retinoid–AP-1 enhancer circuits and drive CD4-dependent tumor immunity in skin cancer.
Authors
Nina Kuprasertkul, Alyssa F. Moore, Carina A. D'souza, Julia Chini, Eun-Kyung Ko, Sijia Huang, Shuo Zhang, Ashley S. Anderson, Shaun Egolf, Laura V. Pinheiro, Alison Jaccard, Claudia T. Magahis, Lydia Bao, Yann Aubert, Cyria R. Olingou, Stephen M. Prouty, Donna Brennan-Crispi, David A. Hill, John T. Seykora, Kathryn E. Wellen, Brian C. Capell
Abstract
Ceramides are essential skin lipids for maintaining the mammalian skin permeability barrier, which protects against external stimuli. The precursor of epidermal ceramides, glucosylceramides (GlcCer), is synthesized within granular keratinocytes while its precise cellular transport mechanisms remain poorly characterized. Here, we identified three pathogenic variants in the GLTP gene, which encodes glycolipid transfer protein, in five unrelated families with nonsyndromic epidermal differentiation disorder presenting with generalized skin scaling. The biallelic GLTP variants resulted in loss of competent GLTP expression. CRISPR/Cas9-generated Gltp knockout mice exhibited lethal barrier defects, partially recapitulating the clinical features of our patients. We demonstrated that GLTP facilitated GlcCer transport in differentiated keratinocytes, with its deficiency causing impaired GlcCer trafficking and consequent aberrant retention in lysosomes, thereby disrupted lysosome function. The lysosomal dysfunction impaired autophagy flux, resulting in delayed keratinocyte terminal differentiation, which is expected to compromise the skin barrier integrity and ultimate abnormal scaling. Pharmaceutical inhibition of GlcCer synthesis effectively rescued both autophagy and keratinocyte differentiation defects. Our findings establish GLTP as a novel underlying gene for nonsyndromic epidermal differentiation disorders and unravel its essential role in maintaining skin homeostasis during terminal differentiation by mediating epidermal GlcCer transport.
Authors
Zeqiao Zhang, Shimiao Huang, Adam Jackson, Elizabeth A. Jones, Siddharth Banka, Chao Yang, Sisi Zhao, Kunlun Lv, Sha Peng, Zhimiao Lin, Huijun Wang
Abstract
Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by a type 2 immune response that is not fully understood. Single-cell RNA sequencing (scRNA-seq) of human AD skin and murine models of type 2 inflammation identified transcriptionally distinct fibroblast clusters, revealing unique, IL-4Rɑ-dependent populations of immune-acting fibroblasts. These unbiased findings prompted further investigation into the role of dermal fibroblasts during allergic inflammation. These studies demonstrated that, in an inflammatory environment including TNFɑ, IL-1β and IL-17A, IL-4 and IL-13 stimulate both mouse and human fibroblasts to produce multiple chemokines, including Ccl8, which activates Ccr3 to attract T-cells. In the skin, fibroblasts are the primary source of many of these chemokines, and targeted deletion of IL--4rɑ in mouse fibroblasts reduces T-cell infiltration in a mouse model of AD. Additionally, pharmacologic inhibition of Ccr3, the receptor shared by many chemokines produced by fibroblasts, decreases T-cell infiltration and skin inflammation in AD mouse models. These findings demonstrate that dermal fibroblasts are more than passive structural cells; they actively participate in the type 2 immune response and contribute to AD by producing chemokines that increase inflammation. Targeting the functions of immune-acting fibroblasts could offer an alternative therapeutic approach for AD.
Authors
Tomofumi Numata, Michael Shia, Yoshiyuki Nakamura, Fengwu Li, Hung Chan, Teruaki Nakatsuji, Kellen J. Cavagnero, Jared Simmons, Henry Li, Aaroh Anand Joshi, Marta Palomo-Irigoyen, Richard L. Gallo
Abstract
Authors
Ching-Ni Njauw, Zhenyu Ji, David I. Latoni, Jose Mari Villa-Gonzalez, Shelley McCormick, Raj Kumar, Dmitrii Usoltsev, Mykyta Artomov, Boyi Gan, Hensin Tsao
Abstract
Over 15% of cancers worldwide are caused by viruses. Merkel cell polyomavirus (MCPyV) is the most recently discovered human oncovirus and is the only polyomavirus that drives malignant tumors in humans. Here, we show that MCPyV+ Merkel cell carcinoma is defined by neuroendocrine-lineage core regulatory (CR) transcription factors (TFs) (ATOH1, INSM1, ISL1, LHX3, POU4F3, and SOX2) that were essential for tumor survival and that co-bound chromatin with the viral small T antigen at super enhancers. Moreover, MCPyV integration sites were enriched at these neuroendocrine super enhancers. We further discovered that the MCPyV noncoding control region contained a homeodomain binding motif absent in other polyomaviruses that bound ISL1 and LHX3 and depended on them for T antigen expression. To therapeutically target the CR factors, we used histone deacetylase (HDAC) inhibitors to collapse the chromatin architecture and induce topological blurring of superenhancer loops, abrogating core TF expression and halting tumor growth. To our knowledge, our study presents the first example of oncogenic cross-regulation between viral and human epigenomic circuitry to generate interlocking and essential transcriptional feedback circuits that explain why MCPyV causes neuroendocrine cancer and represent a tumor dependency that can be targeted therapeutically.
Authors
Lingling Miao, David Milewski, Amy Coxon, Tara Gelb, Khalid A. Garman, Jadon Porch, Arushi Khanna, Loren Collado, Natasha T. Hill, Kenneth Daily, Serena Vilasi, Danielle Reed, Tiffany Alexander, Gabriel J. Starrett, Maharshi Chakraborty, Young Song, Rachel Choi, Vineela Gangalapudi, Josiah Seaman, Andrew Morton, Klaus J. Busam, Christopher R. Vakoc, Daniel J. Urban, Min Shen, Matthew D. Hall, Richard Sallari, Javed Khan, Berkley E. Gryder, Isaac Brownell
Abstract
The role of CARD9 in the pathogenesis of various chronic fungal infections has been established; however, the precise mechanisms underlying the pathobiology of these infections remain unclear. We aimed to investigate the specific cellular mechanisms by which CARD9 deficiency contributes to the pathogenesis of chronic fungal infections. Using single-cell RNA sequencing (scRNA-seq), we analyzed the immune cell profiles in skin lesions from both murine and human samples. We focused on macrophage differentiation and signaling pathways influenced by CARD9 deficiency. We found that CARD9 deficiency promotes the differentiation of TREM2high macrophages following fungal stimulation, impairing their antifungal functions and inducing exhaustion-like T helper 1 (Th1) cells. Mechanistically, the NF-κB pathway activation was restricted in CARD9-deficient macrophages, leading to enhanced CREB activation, which in turn exerted a positive regulatory effect on Trem2 expression by activating C/EBPβ. Notably, targeting TREM2 enhanced the antifungal immune response in vivo and in vitro, thereby alleviating the severity of CARD9-deficient subcutaneous dematiaceous fungal infection. Our findings highlight the important role of CARD9 in regulating cutaneous antifungal immunity and identify potential targets for immunotherapy in chronic dematiaceous fungal infections.
Authors
Lu Zhang, Zhichun Tang, Yi Zhang, Wenjie Liu, Haitao Jiang, Li Yu, Kexin Lei, Yubo Ma, Yang-xin Fu, Ruoyu Li, Wenyan Wang, Fan Bai, Xiaowen Wang
Abstract
Authors
Kristy Tefft, Amy Wang, Zachary Z. Reinstein, Yue Zhang, Arundhati Pillai, Sunghee Hwang, Spencer Ng, Raymond J. Cho, Jeffrey B. Cheng, Fei Li Kuang, Brett King, Jaehyuk Choi
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)