Lipids in the stratum corneum of atopic dermatitis (AD) patients differ substantially in composition from healthy subjects. We hypothesized that hyperactivated type 2 immune response alters AD skin lipid metabolism. We have analyzed stratum corneum lipids from nonlesional and lesional skin of AD subjects and IL-13 skin-specific Tg mice. We also directly examined the effects of IL-4/IL-13 on human keratinocytes in vitro. Mass spectrometric analysis of lesional stratum corneum from AD subjects and IL-13 Tg mice revealed an increased proportion of short-chain (N-14:0 to N-24:0) NS ceramides, sphingomyelins, and 14:0–22:0 lysophosphatidylcholines (14:0–22:0 LPC) with a simultaneous decline in the proportion of corresponding long-chain species (N-26:0 to N-32:0 sphingolipids and 24:0–30:0 LPC) when compared with healthy controls. An increase in short-chain LPC species was also observed in nonlesional AD skin. Similar changes were observed in IL-4/IL-13–driven responses in Ca2+-differentiated human keratinocytes in vitro, all being blocked by STAT6 silencing with siRNA. RNA sequencing analysis performed on stratum corneum of AD as compared with healthy subjects identified decreased expression of fatty acid elongases ELOVL3 and ELOVL6 that contributed to observed changes in atopic skin lipids. IL-4/IL-13 also inhibited ELOVL3 and ELOVL6 expression in keratinocyte cultures in a STAT6-dependent manner. Downregulation of ELOVL3/ELOVL6 expression in keratinocytes by siRNA decreased the proportion of long-chain fatty acids globally and in sphingolipids. Thus, our data strongly support the pathogenic role of type 2 immune activation in AD skin lipid metabolism.
Evgeny Berdyshev, Elena Goleva, Irina Bronova, Nathan Dyjack, Cydney Rios, John Jung, Patricia Taylor, Mingeum Jeong, Clifton F. Hall, Brittany N. Richers, Kathryn A. Norquest, Tao Zheng, Max A. Seibold, Donald Y.M. Leung
Advanced basal cell carcinomas (BCCs) circumvent Smoothened (SMO) inhibition by activating GLI transcription factors to sustain the high levels of Hedgehog (HH) signaling required for their survival. Unfortunately, there is a lack of efficacious therapies. We performed a gene expression–based drug repositioning screen in silico and identified the FDA-approved histone deacetylase (HDAC) inhibitor, vorinostat, as a top therapeutic candidate. We show that vorinostat only inhibits proliferation of BCC cells in vitro and BCC allografts in vivo at high dose, limiting its usefulness as a monotherapy. We leveraged this in silico approach to identify drug combinations that increase the therapeutic window of vorinostat and identified atypical PKC Ɩ/ʎ (aPKC) as a HDAC costimulator of HH signaling. We found that aPKC promotes GLI1-HDAC1 association in vitro, linking two positive feedback loops. Combination targeting of HDAC1 and aPKC robustly inhibited GLI1, lowering drug doses needed in vitro, in vivo, and ex vivo in patient-derived BCC explants. We identified a bioavailable and selective small-molecule aPKC inhibitor, bringing the pharmacological blockade of aPKC and HDAC1 into the realm of clinical possibility. Our findings provide a compelling rationale and candidate drugs for combined targeting of HDAC1 and aPKC in HH-dependent cancers.
Amar N. Mirza, Micah A. Fry, Nicole M. Urman, Scott X. Atwood, Jon Roffey, Gregory R. Ott, Bin Chen, Alex Lee, Alexander S. Brown, Sumaira Z. Aasi, Tyler Hollmig, Mark A. Ator, Bruce D. Dorsey, Bruce R. Ruggeri, Craig A. Zificsak, Marina Sirota, Jean Y. Tang, Atul Butte, Ervin Epstein, Kavita Y. Sarin, Anthony E. Oro
BACKGROUND. Lack of investigatory and diagnostic tools has been a major contributing factor to the failure to mechanistically understand lymphedema and other lymphatic disorders in order to develop effective drug and surgical therapies. One difficulty has been understanding the true changes in lymph vessel pathology from standard 2D tissue sections. METHODS. VIPAR (volume information-based histopathological analysis by 3D reconstruction and data extraction), a light-sheet microscopy–based approach for the analysis of tissue biopsies, is based on digital reconstruction and visualization of microscopic image stacks. VIPAR allows semiautomated segmentation of the vasculature and subsequent nonbiased extraction of characteristic vessel shape and connectivity parameters. We applied VIPAR to analyze biopsies from healthy lymphedematous and lymphangiomatous skin. RESULTS. Digital 3D reconstruction provided a directly visually interpretable, comprehensive representation of the lymphatic and blood vessels in the analyzed tissue volumes. The most conspicuous features were disrupted lymphatic vessels in lymphedematous skin and a hyperplasia (4.36-fold lymphatic vessel volume increase) in the lymphangiomatous skin. Both abnormalities were detected by the connectivity analysis based on extracted vessel shape and structure data. The quantitative evaluation of extracted data revealed a significant reduction of lymphatic segment length (51.3% and 54.2%) and straightness (89.2% and 83.7%) for lymphedematous and lymphangiomatous skin, respectively. Blood vessel length was significantly increased in the lymphangiomatous sample (239.3%). CONCLUSION. VIPAR is a volume-based tissue reconstruction data extraction and analysis approach that successfully distinguished healthy from lymphedematous and lymphangiomatous skin. Its application is not limited to the vascular systems or skin. FUNDING. Max Planck Society, DFG (SFB 656), and Cells-in-Motion Cluster of Excellence EXC 1003.
René Hägerling, Dominik Drees, Aaron Scherzinger, Cathrin Dierkes, Silvia Martin-Almedina, Stefan Butz, Kristiana Gordon, Michael Schäfers, Klaus Hinrichs, Pia Ostergaard, Dietmar Vestweber, Tobias Goerge, Sahar Mansour, Xiaoyi Jiang, Peter S. Mortimer, Friedemann Kiefer
BACKGROUND. Programmed death 1 (PD-1) inhibition activates partially exhausted cytotoxic T lymphocytes (peCTLs) and induces tumor regression. We previously showed that the peCTL fraction predicts response to anti–PD-1 monotherapy. Here, we sought to correlate peCTL and regulatory T lymphocyte (Treg) levels with response to combination immunotherapy, and with demographic/disease characteristics, in metastatic melanoma patients. METHODS. Pretreatment melanoma samples underwent multiparameter flow cytometric analysis. Patients were treated with anti–PD-1 monotherapy or combination therapy, and responses determined by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) criteria. peCTL and Treg levels across demographic/disease variables were compared. Low versus high peCTL (≤20% vs. >20%) were defined from a previous study. RESULTS. One hundred and two melanoma patients were identified. The peCTL fraction was higher in responders than nonresponders. Low peCTL correlated with female sex and liver metastasis, but not with lactate dehydrogenase (LDH), tumor stage, or age. While overall response rates (ORRs) to anti–PD-1 monotherapy and combination therapy were similar in high-peCTL patients, low-peCTL patients given combination therapy demonstrated higher ORRs than those who received monotherapy. Treg levels were not associated with these factors nor with response. CONCLUSION. In melanoma, pretreatment peCTL fraction is reduced in women and in patients with liver metastasis. In low-peCTL patients, anti–PD-1 combination therapy is associated with significantly higher ORR than anti–PD-1 monotherapy. Fewer tumor-infiltrating peCTLs may be required to achieve response to combination immunotherapy. TRIAL REGISTRATION. UCSF IRB Protocol 138510 FUNDING. NIH DP2-AR068130, K08-AR062064, AR066821, and Burroughs Wellcome CAMS-1010934 (M.D.R.). Amoroso and Cook Fund, and the Parker Institute for Cancer Immunotherapy (A.I.D.).
Kimberly Loo, Katy K. Tsai, Kelly Mahuron, Jacqueline Liu, Mariela L. Pauli, Priscila M. Sandoval, Adi Nosrati, James Lee, Lawrence Chen, Jimmy Hwang, Lauren S. Levine, Matthew F. Krummel, Alain P. Algazi, Michael D Alvarado, Michael D. Rosenblum, Adil I. Daud
Tristetraprolin (TTP, encoded by the Zfp36 gene) regulates the mRNA stability of several important cytokines. Due to the critical role of this RNA-binding protein in the control of inflammation, TTP deficiency leads to the spontaneous development of a complex inflammatory syndrome. So far, this phenotype has been largely attributed to dysregulated production of TNF and IL‑23 by myeloid cells, such as macrophages or DCs. Here, we generated mice with conditional deletion of TTP in keratinocytes (Zfp36fl/flK14-Cre mice, referred to herein as Zfp36ΔEP mice). Unlike DC-restricted (CD11c-Cre) or myeloid cell–restricted (LysM-Cre) TTP ablation, these mice developed exacerbated inflammation in the imiquimod-induced psoriasis model. Furthermore, Zfp36ΔEP mice progressively developed a spontaneous pathology with systemic inflammation, psoriatic-like skin lesions, and dactylitis. Finally, we provide evidence that keratinocyte-derived TNF production drives these different pathological features. In summary, these findings expand current views on the initiation of psoriasis and related arthritis by revealing the keratinocyte-intrinsic role of TTP.
Mathieu Andrianne, Assiya Assabban, Caroline La, Denis Mogilenko, Delphine Staumont Salle, Sébastien Fleury, Gilles Doumont, Gaëtan Van Simaeys, Sergei A. Nedospasov, Perry J. Blackshear, David Dombrowicz, Stanislas Goriely, Laurye Van Maele
Pemphigus vulgaris (PV) is an epithelial blistering disease caused by autoantibodies to the desmosomal cadherin desmoglein 3 (DSG3). Glucocorticoids improve disease within days by increasing DSG3 gene transcription, although the mechanism for this observation remains unknown. Here, we show that DSG3 transcription in keratinocytes is regulated by Stat3. Treatment of primary human keratinocytes (PHKs) with hydrocortisone or rapamycin, but not the p38 MAPK inhibitor SB202190, significantly increases DSG3 mRNA and protein expression and correspondingly reduces phospho-S727 Stat3. Stat3 inhibition or shRNA-knockdown also significantly increases DSG3 mRNA and protein levels. Hydrocortisone- or rapamycin-treated PHKs demonstrate increased number and length of desmosomes by electron microscopy and are resistant to PV IgG–induced loss of cell adhesion, whereas constitutive activation of Stat3 in PHKs abrogates DSG3 upregulation and inhibits hydrocortisone and rapamycin’s therapeutic effects. Topical hydrocortisone, rapamycin, or Stat3 inhibitor XVIII prevents autoantibody-induced blistering in the PV passive transfer mouse model, correlating with increased epidermal DSG3 expression and decreased phospho-S727 Stat3. Our data indicate that glucocorticoids and rapamycin upregulate DSG3 transcription through inhibition of Stat3. These studies explain how glucocorticoids rapidly improve pemphigus and may also offer novel insights into the physiologic and pathophysiologic regulation of desmosomal cadherin expression in normal epidermis and epithelial carcinomas.
Xuming Mao, Michael Jeffrey T. Cho, Christoph T. Ellebrecht, Eric M. Mukherjee, Aimee S. Payne
Brateil Badal, Alexander Solovyov, Serena Di Cecilia, Joseph Minhow Chan, Li-Wei Chang, Ramiz Iqbal, Iraz T. Aydin, Geena S. Rajan, Chen Chen, Franco Abbate, Kshitij S. Arora, Antoine Tanne, Stephen B. Gruber, Timothy M. Johnson, Douglas R. Fullen, Leon Raskin, Robert Phelps, Nina Bhardwaj, Emily Bernstein, David T. Ting, Georg Brunner, Eric E. Schadt, Benjamin D. Greenbaum, Julide Tok Celebi
Despite the rising incidence of autoimmunity, therapeutic options for patients with autoimmune disease still rely on decades-old immunosuppressive strategies that risk severe and potentially fatal complications. Thus, novel therapeutic approaches for autoimmune diseases are greatly needed in order to minimize treatment-related toxicity. Such strategies would ideally target only the autoreactive immune components to preserve beneficial immunity. Here, we review how several decades of basic, translational, and clinical research on the immunology of pemphigus vulgaris (PV), an autoantibody-mediated skin disease, have enabled the development of targeted immunotherapeutic strategies. We discuss research to elucidate the pathophysiology of PV and how the knowledge afforded by these studies has led to the preclinical and clinical testing of targeted approaches to neutralize autoantibodies, to induce antigen-specific tolerance, and to specifically eliminate autoreactive B cells in PV.
Christoph T. Ellebrecht, Aimee S. Payne
Systemic sclerosis (SSc) is a rare autoimmune disease with the highest case-fatality rate of all connective tissue diseases. Current efforts to determine patient response to a given treatment using the modified Rodnan skin score (mRSS) are complicated by interclinician variability, confounding, and the time required between sequential mRSS measurements to observe meaningful change. There is an unmet critical need for an objective metric of SSc disease severity. Here, we performed an integrated, multicohort analysis of SSc transcriptome data across 7 datasets from 6 centers composed of 515 samples. Using 158 skin samples from SSc patients and healthy controls recruited at 2 centers as a discovery cohort, we identified a 415-gene expression signature specific for SSc, and validated its ability to distinguish SSc patients from healthy controls in an additional 357 skin samples from 5 independent cohorts. Next, we defined the SSc skin severity score (4S). In every SSc cohort of skin biopsy samples analyzed in our study, 4S correlated significantly with mRSS, allowing objective quantification of SSc disease severity. Using transcriptome data from the largest longitudinal trial of SSc patients to date, we showed that 4S allowed us to objectively monitor individual SSc patients over time, as (a) the change in 4S of a patient is significantly correlated with change in the mRSS, and (b) the change in 4S at 12 months of treatment could predict the change in mRSS at 24 months. Our results suggest that 4S could be used to distinguish treatment responders from nonresponders prior to mRSS change. Our results demonstrate the potential clinical utility of a novel robust molecular signature and a computational approach to SSc disease severity quantification.
Shane Lofgren, Monique Hinchcliff, Mary Carns, Tammara Wood, Kathleen Aren, Esperanza Arroyo, Peggie Cheung, Alex Kuo, Antonia Valenzuela, Anna Haemel, Paul J. Wolters, Jessica Gordon, Robert Spiera, Shervin Assassi, Francesco Boin, Lorinda Chung, David Fiorentino, Paul J. Utz, Michael L. Whitfield, Purvesh Khatri
Psoriasis patients are at increased risk of heart attack and stroke and have elevated MRP8/14 levels that predict heart attack. The KC-Tie2 psoriasiform mouse model exhibits elevated MRP8/14 and is prothrombotic.
Yunmei Wang, Jackelyn B. Golden, Yi Fritz, Xiufen Zhang, Doina Diaconu, Maya I. Camhi, Huiyun Gao, Sean M. Dawes, Xianying Xing, Santhi K. Ganesh, Johann E. Gudjonsson, Daniel I. Simon, Thomas S. McCormick, Nicole L. Ward
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