BACKGROUND. Merkel cell carcinoma (MCC) is an aggressive neuroendocrine (NE) skin cancer caused by severe UV-induced mutations or expression of Merkel cell polyomavirus (MCPyV) large and small T antigens (LT and ST). Despite deep genetic differences between MCPyV-positive and -negative subtypes, current clinical diagnostic markers are indistinguishable between subtypes and the expression profile of MCC tumors is unexplored. METHODS. Here we leveraged bulk and single-cell RNA sequencing of patient-derived tumor biopsies and cell lines to explore the underlying transcriptional diversity of MCC. RESULTS. Strikingly, MCC samples could be separated into transcriptional subtypes that were independent of MCPyV status. Instead, we observed an inverse correlation between a NE gene signature and the Hippo pathway transcription factors Yes1-associated transcriptional regulator (YAP1) and WW domain containing transcriptional regulator (WWTR1). This inverse correlation was present at the transcript and protein levels in the tumor biopsies as well as in established and patient-derived cell lines. Mechanistically, expression of YAP1 or WWTR1 in a MCPyV-positive MCC cell line induced cell-cycle arrest at least in part through TEAD-dependent transcriptional repression of MCPyV LT. CONCLUSION. These findings describe previously unrecognized heterogeneity in NE gene expression within MCC and support the model that YAP1/WWTR1 silencing is essential for the development of MCPyV-positive MCC. FUNDING. US Public Health Service grants R35CA232128, P01CA203655, and P30CA06516.
Thomas C. Frost, Ashley K. Gartin, Mofei Liu, Jingwei Cheng, Harita Dharaneeswaran, Derin B. Keskin, Catherine J. Wu, Anita Giobbie-Hurder, Manisha Thakuria, James A. DeCaprio
BACKGROUND. Acute febrile neutrophilic dermatosis (Sweet syndrome) is a potentially fatal multiorgan inflammatory disease characterized by fever, leukocytosis, and a rash with a neutrophilic infiltrate. Disease pathophysiology remains elusive, and current dogma suggests Sweet syndrome is a “reactive” process to an unknown antigen. Corticosteroids and steroid-sparing agents remain front-line therapies, but refractory cases pose a clinical challenge. METHODS. A 51-year-old woman with multiorgan Sweet syndrome developed serious corticosteroid-related side effects and was refractory to steroid-sparing agents. Blood counts, liver enzymes, and skin histopathology supported the diagnosis. Whole genome sequencing, transcriptomic profiling, and cellular assays of patient’s skin and neutrophils were performed. RESULTS. We identified elevated IL-1 signaling in lesional Sweet syndrome skin caused by a PIK3R1 gain-of-function mutation specifically found in neutrophils. This mutation increased neutrophil migration towards IL-1β and neutrophil respiratory burst. Targeted treatment with an IL-1R1 antagonist in the patient resulted in a dramatic therapeutic response and enabled tapering of corticosteroids. CONCLUSIONS. Dysregulated PI3K-AKT signaling is the first signaling pathway linked to Sweet syndrome and suggests Sweet syndrome may be caused by acquired mutations that modulate neutrophil function. Moreover, integration of molecular data across multiple levels identified a distinct subtype within a heterogenous disease that resulted in a rational and successful clinical intervention. Future cases will benefit from efforts to identify potential mutations. The ability to directly interrogate diseased skin allows this method to be generalizable to other inflammatory diseases and demonstrates a potential personalized medicine approach for challenging patients. FUNDING Berstein Foundation, NIH, VA, Moseley Foundation, and H.T. Leung Foundation.
Shreya Bhattacharya, Sayon Basu, Emily Sheng, Christina M. Murphy, Jenny Wei, Anna E. Kersh, Caroline A. Nelson, Joshua S. Bryer, Hovik A. Ashchyan, Katherine T. Steele, Amy K. Forrestel, John T. Seykora, Robert G. Micheletti, William D. James, Misha Rosenbach, Thomas H. Leung
Human-β-defensin (hBD)-3 exhibits antimicrobial and immunomodulatory activities; however, its contribution to autophagy regulation remains unclear, and the role of autophagy in the regulation of the epidermal barrier in atopic dermatitis (AD) is poorly understood. Here, keratinocyte autophagy was restrained in the skin lesions of patients with AD and murine models of AD. Interestingly, hBD-3 alleviated the interleukin-4- and interleukin-13-mediated impairment of the tight junction (TJ) barrier through keratinocyte autophagy activation, which involved aryl hydrocarbon receptor (AhR) signaling. While autophagy deficiency impaired the epidermal barrier and exacerbated inflammation, hBD-3 attenuated skin inflammation and enhanced the TJ barrier in AD. Importantly, hBD-3-mediated improvement of the TJ barrier was abolished in autophagy-deficient AD mice and in AhR-suppressed AD mice, suggesting a role for hBD-3-mediated autophagy in the regulation of the epidermal barrier and inflammation in AD. Thus, autophagy contributes to the pathogenesis of AD, and hBD-3 could be used for therapeutic purposes.
Ge Peng, Saya Tsukamoto, Risa Ikutama, Hai Le Thanh Nguyen, Yoshie Umehara, Juan V. Trujillo-Paez, Hainan Yue, Miho Takahashi, Takasuke Ogawa, Ryoma Kishi, Mitsutoshi Tominaga, Kenji Takamori, Jiro Kitaura, Shun Kageyama, Masaaki Komatsu, Ko Okumura, Hideoki Ogawa, Shigaku Ikeda, François Niyonsaba
An extreme chronic wound tissue microenvironment causes epigenetic gene silencing. Unbiased whole-genome methylome was studied in the wound-edge (WE) tissue of chronic wound patients. A total of 4689 differentially methylated regions (DMRs) were identified in chronic WE compared to unwounded (UW) human skin. Hypermethylation was more frequently observed (3661 DMRs) in the chronic WE compared to hypomethylation (1028 DMRs). Twenty-six hypermethylated DMRs were involved in epithelial to mesenchymal transition (EMT). Bisulfite sequencing validated hypermethylation of a predicted specific upstream regulator TP53. RNA sequencing analysis was performed to qualify findings from methylome analysis. Analysis of the downregulated genes identified the TP53 signaling pathway as being significantly silenced. Direct comparison of hypermethylation and downregulated genes identified four genes, ADAM17, NOTCH, TWIST1 and SMURF1, that functionally represent the EMT pathway. Single-cell RNA sequencing studies identified that these effects on gene expression were limited to the keratinocyte cell compartment. Experimental murine studies established that tissue ischemia potently induces WE gene methylation and that 5’-azacytidine, inhibitor of methylation, improved wound closure. To specifically address the significance of TP53 methylation, keratinocyte-specific editing of TP53 methylation at the WE was achieved by a tissue nanotransfection (TNT) based CRISPR/dCas9 approach. This work identified that reversal of methylation-dependent keratinocyte gene-silencing represents a productive therapeutic strategy to improve wound closure.
Kanhaiya Singh, Yashika Rustagi, Ahmed S. Abouhashem, Saba Tabasum, Priyanka Verma, Edward Hernandez, Durba Pal, Dolly K. Khona, Sujit K. Mohanty, Manishekhar Kumar, Rajneesh Srivastava, Poornachander R Guda, Sumit S. Verma, Sanskruti Mahajan, Jackson A. Killian, Logan A. Walker, Subhadip Ghatak, Shomita S. Mathew-Steiner, Kristen Wanczyk, Sheng Liu, Jun Wan, Pearlly Yan, Ralf Bundschuh, Savita Khanna, Gayle M. Gordillo, Michael P. Murphy, Sashwati Roy, Chandan K. Sen
BACKGROUND. Tuberous Sclerosis Complex (TSC) is a neurogenetic syndrome due to loss-of-function mutations in TSC2 or TSC1, characterized by tumors at multiple body sites, including facial angiofibroma (FAF). Here, an ultrasensitive assessment of the extent and range of UV-induced mutations in TSC facial skin was performed. METHODS. A Multiplex High-sensitivity PCR Assay (MHPA) was developed, enabling mutation detection at extremely low (<0.1%) variant allele frequencies (VAF). RESULTS. MHPA assays were developed for both TSC2 and TP53, and applied to 81 samples, including 66 skin biopsies. UV-induced second hit mutation causing inactivation of TSC2 was pervasive in TSC facial skin with an average of 4.8 mutations per 2 mm biopsy at median VAF 0.08%, generating >150,000 incipient facial tumors (subclinical ‘micro-FAFs’) in the average TSC subject. The MHPA analysis also led to the identification of a refined UV-related indel signature and a recurrent complex mutation pattern, consisting of both a single or dinucleotide variant, and a 1-9 nt deletion, in cis. CONCLUSION. TSC facial skin can be viewed as harboring a patchwork of clonal fibroblast proliferations (micro-FAF) with indolent growth, a small proportion of which develop into clinically observable FAF. Our observations also expand the spectrum of UV-related mutation signatures. FUNDING. This work was supported by the TSC Alliance, Engles Family Fund for Research in TSC and LAM, and National Institutes of Health, National Heart, Lung, and Blood Institute [U01HL131022-04; Intramural Research Program].
Katarzyna Klonowska, Joannes M. Grevelink, Krinio Giannikou, Barbara A. Ogorek, Zachary T. Herbert, Aaron R. Thorner, Thomas N. Darling, Joel Moss, David J. Kwiatkowski
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer that frequently carries an integrated Merkel cell polyomavirus (MCPyV) genome and expresses viral transforming antigens (TAgs). MCC tumor cells also express signature genes detected in skin-resident, post-mitotic Merkel cells, including Atoh1, which is required for Merkel cell development from epidermal progenitors. We now report the use of in vivo cellular reprogramming, using ATOH1, to drive MCC development from murine epidermis. We generated mice that conditionally expressed MCPyV TAgs and ATOH1 in epidermal cells, yielding microscopic collections of proliferating MCC-like cells arising from hair follicles. Immunostaining of these nascent tumors revealed p53 accumulation and apoptosis, and targeted deletion of Trp53 led to development of gross skin tumors with classic MCC histology and marker expression. Global transcriptome analysis confirmed the close similarity of mouse and human MCCs, and hierarchical clustering showed conserved upregulation of signature genes. Our data establish that expression of MCPyV TAgs, in ATOH1-reprogrammed epidermal cells and their neuroendocrine progeny, initiates hair follicle-derived MCC tumorigenesis in adult mice. Moreover, progression to full-blown MCC in this model requires loss of p53, mimicking the functional inhibition of p53 reported in human MCPyV-positive MCCs.
Monique E. Verhaegen, Paul W. Harms, Julia J. Van Goor, Jacob Arche, Matthew T. Patrick, Dawn Wilbert, Haley Zabawa, Marina Grachtchouk, Chia-Jen Liu, Kevin Hu, Michael C. Kelly, Ping Chen, Thomas L. Saunders, Stephan Weidinger, Li-Jyun Syu, John S. Runge, Johann E. Gudjonsson, Sunny Y. Wong, Isaac Brownell, Marcin Cieslik, Aaron M. Udager, Arul M. Chinnaiyan, Lam C. Tsoi, Andrzej A. Dlugosz
Desmoglein 1 (Dsg1) is a cadherin restricted to stratified tissues of terrestrial vertebrates, which serve as essential physical and immune barriers. Dsg1 loss-of-function mutations in humans result in skin lesions, multiple allergies, and isolated patient keratinocytes exhibit increased pro-allergic cytokine expression. However, the mechanism by which genetic deficiency of Dsg1 causes chronic inflammation is unknown. To determine the systemic response to Dsg1 loss, we deleted the three tandem Dsg1 genes in mice. Whole transcriptome analysis of embryonic Dsg1-/- skin showed a delay in expression of adhesion/differentiation/keratinization genes at E17.5, a subset of which recovered or increased by E18.5. Comparing epidermal transcriptomes from Dsg1-deficient mice and humans revealed a shared IL-17-skewed inflammatory signature. Although the impaired intercellular adhesion observed in Dsg1-/- mice resembles that resulting from anti-Dsg1 pemphigus foliaceus antibodies, pemphigus skin lesions exhibit a weaker IL-17 signature. Consistent with the clinical importance of these findings, treatment of two Dsg1-deficient patients with an IL-12/IL-23 antagonist originally developed for psoriasis resulted in improvement of skin lesions. Thus, beyond impairing the physical barrier, loss of Dsg1 function through gene mutation results in a psoriatic-like inflammatory signature before birth and treatment with a targeted therapy markedly improved skin lesions in patients.
Lisa M. Godsel, Quinn R. Roth-Carter, Jennifer L. Koetsier, Lam C. Tsoi, Amber L. Huffine, Joshua A. Broussard, Gillian N. Fitz, Sarah M. Lloyd, Junghun Kweon, Hope E. Burks, Marihan Hegazy, Saki Amagai, Paul W. Harms, Xianying Xing, Joseph Kirma, Jodi L. Johnson, Gloria Urciuoli, Lynn T. Doglio, William R. Swindell, Rajeshwar Awatramani, Eli Sprecher, Xiaomin Bao, Eran Cohen-Barak, Caterina Missero, Johann E. Gudjonsson, Kathleen J. Green
Impaired wound healing associated with recurrent Staphylococcus aureus infection and unresolved inflammation are hallmarks of non-healing diabetic foot ulcers (DFU). Perforin-2, an innate immunity molecule against intracellular bacteria, limits cutaneous infection and dissemination of S. aureus in mice. Here we report the intracellular accumulation of S. aureus in the epidermis of DFU with no clinical signs of infection due to marked suppression of Perforin-2. S. aureus residing within the epidermis of DFU triggers AIM2-inflammasome activation and pyroptosis. These findings were corroborated in mice lacking Perforin-2. The effects of pyroptosis on DFU clinical outcomes were further elucidated in a 4-week longitudinal clinical study in DFU patients undergoing standard of care. Increased AIM2-inflammasome and ASC-pyroptosome coupled with induction of IL-1β were found in non-healing when compared to healing DFU. Our findings reveal novel mechanism that includes Perforin-2 suppression, intracellular S. aureus accumulation and associated induction of pyroptosis that contribute to healing inhibition and prolonged inflammation in patients with DFU.
Irena Pastar, Andrew P. Sawaya, Jelena Marjanovic, Jamie L. Burgess, Natasa Strbo, Katelyn E. Rivas, Tongyu C. Wikramanayake, Cheyanne R. Head, Rivka C. Stone, Ivan Jozic, Olivera Stojadinovic, Eran Y. Kornfeld, Robert S. Kirsner, Hadar Lev-Tov, Marjana Tomic-Canic
Inflammatory disorders of the skin are frequently associated with inflammatory bowel diseases (IBDs). To explore mechanisms by which these organs communicate, we performed single-cell RNA-Seq analysis on fibroblasts from humans and mice with IBD. This analysis revealed that intestinal inflammation promoted differentiation of a subset of intestinal stromal fibroblasts into preadipocytes with innate antimicrobial host defense activity. Furthermore, this process of reactive adipogenesis was exacerbated if mouse skin was inflamed as a result of skin wounding or infection. Since hyaluronan (HA) catabolism is activated during skin injury and fibroblast-to-adipocyte differentiation is dependent on HA, we tested the hypothesis that HA fragments could alter colon fibroblast function by targeted expression of human hyaluronidase-1 in basal keratinocytes from mouse skin. Hyaluronidase expression in the skin activated intestinal stromal fibroblasts, altered the fecal microbiome, and promoted excessive reactive adipogenesis and increased inflammation in the colon after challenge with dextran sodium sulfate. The response to digested HA was dependent on expression of TLR4 by preadipocytes. Collectively, these results suggest that the association between skin inflammation and IBD may be due to recognition by mesenchymal fibroblasts in the colon of HA released during inflammation of the skin.
Tatsuya Dokoshi, Jason S. Seidman, Kellen J. Cavagnero, Fengwu Li, Marc C. Liggins, Bryn C. Taylor, Jocelyn Olvera, Rob Knight, John T. Chang, Nita H. Salzman, Richard L. Gallo
BACKGROUND. The loss of insulin-like growth factor-1 (IGF-1) expression in senescent dermal fibroblasts during aging is associated with an increased risk of non-melanoma skin cancer (NMSC). We tested how IGF-1 signaling can influence photocarcinogenesis during chronic UVB exposure to determine if fractionated laser resurfacing (FLR) of aged skin which upregulates dermal IGF-1 levels can prevent the occurrence of actinic keratosis (AK) and NMSC. METHODS. A human skin/immunodeficient mouse xenografting model was used to test the effects of a small molecule inhibitor of the IGF-1 receptor on chronic UVB radiation. Subsequently, the durability of FLR treatment was tested on a cohort of human subjects aged ≥65. Finally, 48 subjects aged 60 and older with considerable actinic damage were enrolled in a prospective randomized clinical trial in which they underwent a single unilateral FLR treatment of one lower arm. Numbers of AKs/NMSCs were recorded on both extremities for up to 36 months in blinded fashion. RESULTS. Xenografting studies revealed chronic UVB treatment with a topical IGF-1R inhibitor resulted in a pro-carcinogenic response. A single FLR treatment was durable in restoring appropriate UVB response in geriatric skin for at least two years. FLR resulted in sustained reduction in numbers of AKs and decreased numbers of NMSC in the treated (24) versus untreated (2) arms. INTERPRETATION. The elimination of senescent fibroblasts via FLR reduced the pro-carcinogenic UVB response of aged skin. Thus, wounding therapies are potentially effective prophylaxis for managing high-risk populations. TRIAL REGISTRATION. ClinicalTrials.gov NCT03906253. FUNDING. National Institutes of Health, Veterans Administration.
Dan F. Spandau, Roy Chen, Jeffrey J. Wargo, Craig A. Rohan, David Southern, Angela Zhang, Mathew Loesch, Jonathan Weyerbacher, Sunil S. Tholpady, Davina Anne Lewis, Matthew Kuhar, Kenneth Y. Tsai, Amber J. Castellanos, Michael G. Kemp, Michael Markey, Elizabeth Cates, Amy R. Williams, Christina Knisely, Sabina Bashir, Ryan Gabbard, Robert Hoopes, Jeffrey B. Travers