In this study we evaluated the role of hyaluronan (HA) in reactive adipogenesis, a local expansion of preadipocytes that provides host defense by release of antimicrobial peptides. We observed that HA accumulated during maturation of adipocytes in vitro and was associated with increased expression of preadipocyte factor 1, zinc finger protein 423, and early B cell factor 1. Although HA is normally abundant in the extracellular matrix, a further increase in HA staining occurred in mice at sites of reactive adipogenesis following injury of colon by dextran sodium sulfate or injury of skin from infection with Staphylococcus aureus. HA also abundantly accumulated around adipocytes seen in the colons of patients with inflammatory bowel disease. This HA was necessary for adipocyte maturation because digestion of HA by administration of soluble hyaluronidase or transgenic expression of hyaluronidase 1 inhibited adipogenesis in vitro and in vivo. Furthermore, hyaluronidase also suppressed inflammation of both skin and colon and decreased antimicrobial peptide expression by developing preadipocytes. This resulted in increased bacterial transit across the epithelial barrier despite decreased tissue injury from inflammation. These observations suggest HA plays an important role in reactive adipogenesis and host defense after injury.
Tatsuya Dokoshi, Ling-juan Zhang, Teruaki Nakatsuji, Christopher A. Adase, James A. Sanford, Rudolph D. Paladini, Hiroki Tanaka, Mikihiro Fujiya, Richard L. Gallo
Alopecia areata (AA) is an autoimmune disease in which cytotoxic T cells specifically target growing hair follicles. We used high-throughput TCR sequencing in the C3H/HeJ mouse model of AA and in human AA patients to gain insight into pathogenic T cell populations and their dynamics, which revealed clonal CD8+ T cell expansions in lesional skin. In the C3H/HeJ model, we observed interindividual sharing of TCRβ chain protein sequences, which strongly supports a model of antigenic drive in AA. The overlap between the lesional TCR repertoire and a population of CD8+NKG2D+ T cells in skin-draining lymph nodes identified this subset as pathogenic effectors. In AA patients, treatment with the oral JAK inhibitor tofacitinib resulted in a decrease in clonally expanded CD8+ T cells in the scalp but also revealed that many expanded lesional T cell clones do not completely disappear from either skin or blood during treatment with tofacitinib, which may explain in part the relapse of disease after stopping treatment.
Annemieke de Jong, Ali Jabbari, Zhenpeng Dai, Luzhou Xing, Dustin Lee, Mei Mei Li, Madeleine Duvic, Maria Hordinsky, David A. Norris, Vera Price, Julian Mackay-Wiggan, Raphael Clynes, Angela M. Christiano
Organ transplant recipients (OTRs) on cyclosporine A (CSA) are prone to catastrophic cutaneous squamous cell carcinoma (SCC). Allograft-sparing, cancer-targeting systemic treatments are unavailable. We have shown increased risk for catastrophic SCC in OTRs via CSA-mediated induction of IL-22. Herein, we found that CSA drives SCC proliferation and tumor growth through IL-22 and JAK/STAT pathway induction. We in turn inhibited SCC growth with an FDA-approved JAK1/2 inhibitor, ruxolitinib. In human SCC cells, the greatest proliferative response to IL-22 and CSA treatment occurred in nonmetastasizing lines. IL-22 treatment upregulated JAK1 and STAT1/3 in A431 SCC cells. JAK/STAT pathway genes were highly expressed in tumors from a cohort of CSA-exposed OTRs and in SCC with high risk for metastasis. Compared with immunocompetent SCC, genes associated with innate immunity, response to DNA damage, and p53 regulation were differentially expressed in SCC from OTRs. In nude mice engrafted with human A431 cells, IL-22 and CSA treatment increased tumor growth and upregulated IL-22 receptor, JAK1, and STAT1/3 expression. Ruxolitinib treatment significantly reduced tumor volume and reversed the accelerated tumor growth. CSA and IL-22 exacerbate aggressive behavior in SCC. Targeting the IL-22 axis via selective JAK/STAT inhibition may reduce the progression of aggressive SCC in OTRs, without compromising immunosuppression.
Melody Abikhair Burgo, Nazanin Roudiani, Jie Chen, Alexis L. Santana, Nicole Doudican, Charlotte Proby, Diane Felsen, John A. Carucci
Poorly controlled diabetes leads to comorbidities and enhanced susceptibility to infections. While the immune components involved in wound healing in diabetes have been studied, the components involved in susceptibility to skin infections remain unclear. Here, we examined the effects of the inflammatory lipid mediator leukotriene B4 (LTB4) signaling through its receptor B leukotriene receptor 1 (BLT1) in the progression of methicillin-resistant Staphylococcus aureus (MRSA) skin infection in 2 models of diabetes. Diabetic mice produced higher levels of LTB4 in the skin, which correlated with larger nonhealing lesion areas and increased bacterial loads compared with nondiabetic mice. High LTB4 levels were also associated with dysregulated cytokine and chemokine production, excessive neutrophil migration but impaired abscess formation, and uncontrolled collagen deposition. Both genetic deletion and topical pharmacological BLT1 antagonism restored inflammatory response and abscess formation, followed by a reduction in the bacterial load and lesion area in the diabetic mice. Macrophage depletion in diabetic mice limited LTB4 production and improved abscess architecture and skin host defense. These data demonstrate that exaggerated LTB4/BLT1 responses mediate a derailed inflammatory milieu that underlies poor host defense in diabetes. Prevention of LTB4 production/actions could provide a new therapeutic strategy to restore host defense in diabetes.
Stephanie L. Brandt, Sue Wang, Naiara N. Dejani, Nathan Klopfenstein, Seth Winfree, Luciano Filgueiras, Brian P. McCarthy, Paul R. Territo, C. Henrique Serezani
Epithelial cells are the first line of defense against external dangers, and contribute to induction of adaptive immunity including Th17 responses. However, it is unclear whether specific epithelial signaling pathways are essential for the development of robust IL-17–mediated immune responses. In mice, the development of psoriatic inflammation induced by imiquimod required keratinocyte TRAF6. Conditional deletion of TRAF6 in keratinocytes abrogated dendritic cell activation, IL-23 production, and IL-17 production by γδ T cells at the imiquimod-treated sites. In contrast, hapten-induced contact hypersensitivity and papain-induced IgE production were not affected by loss of TRAF6. Loss of psoriatic inflammation was not solely due to defective imiquimod sensing, as subcutaneous administration of IL-23 restored IL-17 production but did not reconstitute psoriatic pathology in the mutant animals. Thus, TRAF6 was required for the full development of IL-17–mediated inflammation. Therefore, epithelial TRAF6 signaling plays an essential role in both triggering and propagating IL-17–mediated psoriatic inflammation.
Reiko Matsumoto, Teruki Dainichi, Soken Tsuchiya, Takashi Nomura, Akihiko Kitoh, Matthew S. Hayden, Ken J. Ishii, Mayuri Tanaka, Tetsuya Honda, Gyohei Egawa, Atsushi Otsuka, Saeko Nakajima, Kenji Sakurai, Yuri Nakano, Takashi Kobayashi, Yukihiko Sugimoto, Kenji Kabashima
Innate DNA repair mechanisms play a critical role in protecting skin keratinocytes from UV mutagenesis and skin cancer development. We hypothesized that individuals who develop frequent skin cancers may harbor germline defects in DNA repair genes and have increased predisposition to internal malignancies. We enrolled 61 patients with unusually frequent basal cell carcinoma (BCC) development, seen at Stanford Hospital and Clinics from January 2005 until December 2015, for germline analysis of 29 DNA repair genes. In parallel, a case-control retrospective review was performed to interrogate the association of malignancies with frequent BCC development in a large US medical insurance claims database (Truven), which included 13,264 individuals with 6 or more BCCs from 2007 to 2011. 19.7% of the frequent BCC cohort harbored pathogenic mutations in DNA repair genes: APC, BARD1, BRCA1, BRCA2, CDH1, CHEK2, MLH1, MSH2, MSH6, MUTYH, NBN, and PALB2. Individuals with 6 or more BCCs had an increased risk of other malignancies, with a 3.5-fold increase in the frequent BCC cohort and a 3.2-fold increase in the Truven database. Individuals who developed frequent BCCs have an increased prevalence of germline mutations in DNA repair genes and increased malignancy risk. Our data implicate frequent BCC development as an external marker of inherited cancer risk.
Hyunje G. Cho, Karen Y. Kuo, Shufeng Li, Irene Bailey, Sumaira Aasi, Anne Lynn S. Chang, Anthony E. Oro, Jean Y. Tang, Kavita Y. Sarin
Numerous studies of relatively few patients have linked T cell receptor (TCR) genes to psoriasis but have yielded dramatically conflicting results. To resolve these discrepancies, we have chosen to mine RNA-Seq datasets for patterns of TCR gene segment usage in psoriasis. A meta-analysis of 3 existing and 1 unpublished datasets revealed a statistically significant link between the relative expression of TRAJ23 and psoriasis and the psoriasis-associated cytokine IL-17A. TRGV5, a TCR-γ segment, was also associated with psoriasis but correlated instead with IL-36A, other IL-36 family members, and IL-17C (not IL-17A). In contrast, TRAJ39 was strongly associated with healthy skin. T cell diversity measurements and analysis of CDR3 sequences were also conducted, revealing no psoriasis-associated public CDR3 sequences. Finally, in comparison with the expression of TCR-αβ genes, the expression of TCR-γδ genes was relatively low but mildly elevated in psoriatic skin. These results have implications for the development of targeted therapies for psoriasis and other autoimmune diseases. Also, the techniques employed in this study have applications in other fields, such as cancer immunology and infectious disease.
Alexander A. Merleev, Alina I. Marusina, Chelsea Ma, James T. Elder, Lam C. Tsoi, Siba P. Raychauduri, Stephan Weidinger, Elizabeth A. Wang, Iannis E. Adamopoulos, Guillaume Luxardi, Johann E. Gudjonsson, Michiko Shimoda, Emanual Maverakis
The underlying pathology of atopic dermatitis (AD) includes impaired skin barrier function, susceptibility to Staphylococcus aureus skin infection, immune dysregulation, and cutaneous dysbiosis. Our recent investigation into the potential role of Gram-negative skin bacteria in AD revealed that isolates of one particular commensal, Roseomonas mucosa, collected from healthy volunteers (HVs) improved outcomes in mouse and cell culture models of AD. In contrast, isolates of R. mucosa from patients with AD worsened outcomes in these models. These preclinical results suggested that interventions targeting the microbiome could provide therapeutic benefit for patients with AD. As a first test of this hypothesis in humans, 10 adult and 5 pediatric patients were enrolled in an open-label phase I/II safety and activity trial (the Beginning Assessment of Cutaneous Treatment Efficacy for Roseomonas in Atopic Dermatitis trial; BACTERiAD I/II). Treatment with R. mucosa was associated with significant decreases in measures of disease severity, topical steroid requirement, and S. aureus burden. There were no adverse events or treatment complications. We additionally evaluated differentiating bacterial metabolites and topical exposures that may contribute to the skin dysbiosis associated with AD and/or influence future microbiome-based treatments. These early results support continued evaluation of R. mucosa therapy with a placebo-controlled trial.
Ian A. Myles, Noah J. Earland, Erik D. Anderson, Ian N. Moore, Mark D. Kieh, Kelli W. Williams, Arhum Saleem, Natalia M. Fontecilla, Pamela A. Welch, Dirk A. Darnell, Lisa A. Barnhart, Ashleigh A. Sun, Gulbu Uzel, Sandip K. Datta
Heterozygous chromosomal inversions suppress recombination. Therefore, they may potentially influence recombination-associated phenotypes of human diseases, but no studies have verified this hypothesis. Here, we describe a 35-year-old man with severe congenital ichthyosis. Mutation analysis revealed a heterozygous splice-site mutation, c.1374-2A>G (p.Ser458Argfs*120), in KRT10 on 17q21.2. This mutation was previously reported in patients with ichthyosis with confetti type I (IWC-I), a prominent skin disease characterized by the frequent occurrence of recombination-induced reversion of pathogenic mutations. Intriguingly, the number of revertant skin areas in this patient is considerably reduced compared with typical IWC-I cases. G-banded karyotyping revealed that the patient harbors a heterozygous nonpathogenic inversion, inv(17)(p13q12), whose long-arm breakpoint was subsequently refined to chromosomal positions (chr17: 36,544,407–36,639,830) via FISH. Collectively, the only chance of revertant mosaicism through somatic recombination appears to involve recombination between the KRT10 mutation and the inversion breakpoint. Indeed, in the examined revertant spot, the KRT10 mutation was diminished by somatic recombination starting from chromosomal positions (chr17: 36,915,505–37,060,285) on 17q12. This study provides the first evidence to our knowledge implicating chromosomal inversions as a potential modifier of clinical phenotypes. Furthermore, the reduced occurrence of revertant spots in the recombination-suppressed patient suggests that somatic recombination is the main mechanism of revertant mosaicism in IWC-I.
Toshifumi Nomura, Shotaro Suzuki, Toshinari Miyauchi, Masae Takeda, Satoru Shinkuma, Yasuyuki Fujita, Wataru Nishie, Masashi Akiyama, Hiroshi Shimizu
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
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