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Ruchti F, Zwicky P, Becher B, Dubrac S, LeibundGut-Landmann S. Epidermal barrier impairment predisposes for excessive growth of the allergy-associated yeast Malassezia on murine skin. Allergy 2024. [PMID: 38385963 DOI: 10.1111/all.16062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND The skin barrier is vital for protection against environmental threats including insults caused by skin-resident microbes. Dysregulation of this barrier is a hallmark of atopic dermatitis (AD) and ichthyosis, with variable consequences for host immune control of colonizing commensals and opportunistic pathogens. While Malassezia is the most abundant commensal fungus of the skin, little is known about the host control of this fungus in inflammatory skin diseases. METHODS In this experimental study, MC903-treated mice were colonized with Malassezia spp. to assess the host-fungal interactions in atopic dermatitis. Additional murine models of AD and ichthyosis, including tape stripping, K5-Nrf2 overexpression and flaky tail mice, were employed to confirm and expand the findings. Skin fungal counts were enumerated. High parameter flow cytometry was used to characterize the antifungal response in the AD-like skin. Structural and functional alterations in the skin barrier were determined by histology and transcriptomics of bulk skin. Finally, differential expression of metabolic genes in Malassezia in atopic and control skin was quantified. RESULTS Malassezia grows excessively in AD-like skin. Fungal overgrowth could, however, not be explained by the altered immune status of the atopic skin. Instead, we found that by upregulating key metabolic genes in the altered cutaneous niche, Malassezia acquired enhanced fitness to efficiently colonise the impaired skin barrier. CONCLUSIONS This study provides evidence that structural and metabolic changes in the dysfunctional epidermal barrier environment provide increased accessibility and an altered lipid profile, to which the lipid-dependent yeast adapts for enhanced nutrient assimilation. Our findings reveal fundamental insights into the implication of the mycobiota in the pathogenesis of common skin barrier disorders.
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Affiliation(s)
- Fiorella Ruchti
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Pascale Zwicky
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Burkhard Becher
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Sandrine Dubrac
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Salomé LeibundGut-Landmann
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
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Ruchti F, Tuor M, Mathew L, McCarthy NE, LeibundGut-Landmann S. γδ T cells respond directly and selectively to the skin commensal yeast Malassezia for IL-17-dependent fungal control. PLoS Pathog 2024; 20:e1011668. [PMID: 38215167 PMCID: PMC10810444 DOI: 10.1371/journal.ppat.1011668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/25/2024] [Accepted: 12/16/2023] [Indexed: 01/14/2024] Open
Abstract
Stable microbial colonization of the skin depends on tight control by the host immune system. The lipid-dependent yeast Malassezia typically colonizes skin as a harmless commensal and is subject to host type 17 immunosurveillance, but this fungus has also been associated with diverse skin pathologies in both humans and animals. Using a murine model of Malassezia exposure, we show that Vγ4+ dermal γδ T cells expand rapidly and are the major source of IL-17A mediating fungal control in colonized skin. A pool of memory-like Malassezia-responsive Vγ4+ T cells persisted in the skin, were enriched in draining lymph nodes even after fungal clearance, and were protective upon fungal re-exposure up to several weeks later. Induction of γδT17 immunity depended on IL-23 and IL-1 family cytokine signalling, whereas Toll-like and C-type lectin receptors were dispensable. Furthermore, Vγ4+ T cells from Malassezia-exposed hosts were able to respond directly and selectively to Malassezia-derived ligands, independently of antigen-presenting host cells. The fungal moieties detected were shared across diverse species of the Malassezia genus, but not conserved in other Basidiomycota or Ascomycota. These data provide novel mechanistic insight into the induction and maintenance of type 17 immunosurveillance of skin commensal colonization that has significant implications for cutaneous health.
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Affiliation(s)
- Fiorella Ruchti
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Meret Tuor
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Liya Mathew
- Centre for Immunobiology, Bart’s and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Neil E McCarthy
- Centre for Immunobiology, Bart’s and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Salomé LeibundGut-Landmann
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
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Ruchti F, LeibundGut-Landmann S. New insights into immunity to skin fungi shape our understanding of health and disease. Parasite Immunol 2023; 45:e12948. [PMID: 36047038 PMCID: PMC10078452 DOI: 10.1111/pim.12948] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/18/2022] [Accepted: 08/25/2022] [Indexed: 01/31/2023]
Abstract
Fungi represent an integral part of the skin microbiota. Their complex interaction network with the host shapes protective immunity during homeostasis. If host defences are breached, skin-resident fungi including Malassezia and Candida, and environmental fungi such as dermatophytes can cause cutaneous infections. In addition, fungi are associated with diverse non-infectious skin disorders. Despite their multiple roles in health and disease, fungi remain elusive and understudied, and the mechanisms underlying the emergence of pathological conditions linked to fungi are largely unclear. The identification of IL-17 as an important antifungal effector mechanism represents a milestone for understanding homeostatic antifungal immunity. At the same time, host-adverse, disease-promoting roles of IL-17 have been delineated, as in psoriasis. Fungal dysbiosis represents another feature of many pathological skin conditions with an unknown causal link of intra- and interkingdom interactions to disease pathogenesis. The emergence of new fungal pathogens such as Candida auris highlights the need for more research into fungal immunology to understand how antifungal responses shape health and diseases. Recent technological advances for genetically manipulating fungi to target immunomodulatory fungal determinants, multi-omics approaches for studying immune cells in the human skin, and novel experimental models open up a promising future for skin fungal immunity.
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Affiliation(s)
- Fiorella Ruchti
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland.,Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Salomé LeibundGut-Landmann
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland.,Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
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Goh J, Ruchti F, Poh SE, Koh WL, Tan KY, Lim YT, Thng ST, Sobota RM, Hoon SS, Liu C, O'Donoghue AJ, LeibundGut-Landmann S, Oon HH, Li H, Dawson TL. S1.3d The human pathobiont Malassezia furfur secreted protease MfSAP1 regulates cell dispersal and exacerbates skin inflammation. Med Mycol 2022. [PMCID: PMC9515860 DOI: 10.1093/mmy/myac072.s1.3d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
S1.3 Malassezia: genetics, genomics, and biology, September 21, 2022, 11:00 AM - 12:30 PM Objectives Malassezia forms the dominant eukaryotic microbial community on the human skin. The Malassezia genus possesses a repertoire of secretory hydrolytic enzymes involved in protein and lipid metabolism which alter the external cutaneous environment. The exact role of most Malassezia secreted enzymes, including those in interaction with the epithelial surface, is not well characterized. Methods and Results In this study, we compared the expression level of secreted proteases, lipases, phospholipases, and sphingomyelinases of M. globosa in healthy subjects and seborrheic dermatitis or atopic dermatitis patients. We observed upregulated gene expression of the previously characterized secretory aspartyl protease MgSAP1 in both the lesional and non-lesional skin sites of affected compared to healthy subjects. To explore the functional roles of MgSAP1 in skin disease, we generated a knockout mutant of the homologous protease MfSAP1 in the genetically tractable M. furfur. We observed the loss of MfSAP1 resulted in dramatic changes in the cell adhesion and dispersal in both culture and a human 3D reconstituted epidermis model. In a murine model of Malassezia colonization, we further demonstrated MfSAP1 contributes to inflammation as observed by reduced edema and myeloid pustule formation with the knockout mutant versus wildtype. Conclusion Taken together, we show that this dominant secretory M. aspartyl protease has an important role in enabling a planktonic cellular state that can potentially aid in colonization and additionally as a virulence factor in barrier-compromised skin, further highlighting the importance of considering the contextual relevance when evaluating the functions of secreted microbial enzymes.
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Affiliation(s)
- Joleen Goh
- A*STAR Skin Research Labs , Agency for Science, Technology and Research, Singapore , Singapore
| | - Fiorella Ruchti
- Section of Immunology , Vetsuisse Faculty, University of Zürich , Switzerland
| | - Si En Poh
- Molecular Engineering Lab , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Winston L.C. Koh
- Molecular Engineering Lab , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Kiat Yi Tan
- Functional Proteomics Laboratory , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Yan Ting Lim
- Functional Proteomics Laboratory , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Steven T.G. Thng
- National Skin Centre , National Health Group, Singapore , Singapore
| | - Radoslaw M. Sobota
- Functional Proteomics Laboratory , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Shawn S. Hoon
- Molecular Engineering Lab , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
| | - Chenxi Liu
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of California-San Diego, La Jolla , USA
| | - Anthony J. O'Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of California-San Diego, La Jolla , USA
| | | | - Hazel H. Oon
- National Skin Centre , National Health Group, Singapore , Singapore
| | - Hao Li
- Molecular Engineering Lab , Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore , Singapore
- Department of Chemistry , National University of Singapore, Singapore , Singapore
| | - Thomas L. Dawson
- A*STAR Skin Research Labs , Agency for Science, Technology and Research, Singapore , Singapore
- Department of Drug Discovery , School of Pharmacy, Medical University of South Carolina, Charleston , USA
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Zwicky P, Ingelfinger F, Silva de Melo BM, Ruchti F, Schärli S, Puertas N, Lutz M, Phan TS, Kündig TM, Levesque MP, Maul JT, Schlapbach C, LeibundGut-Landmann S, Mundt S, Becher B. IL-12 regulates type 3 immunity through interfollicular keratinocytes in psoriasiform inflammation. Sci Immunol 2021; 6:eabg9012. [PMID: 34678045 DOI: 10.1126/sciimmunol.abg9012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Pascale Zwicky
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Florian Ingelfinger
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Bruno Marcel Silva de Melo
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland.,Center for Research in Inflammatory Diseases, Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirão Preto Sao Paulo, Brazil
| | - Fiorella Ruchti
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland.,Section of Immunology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Stefanie Schärli
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Nicole Puertas
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Mirjam Lutz
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Truong San Phan
- Department of Dermatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Thomas M Kündig
- Department of Dermatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Mitchell P Levesque
- Department of Dermatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Julia-Tatjana Maul
- Department of Dermatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Christoph Schlapbach
- Department of Dermatology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Salomé LeibundGut-Landmann
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland.,Section of Immunology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Sarah Mundt
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
| | - Burkhard Becher
- Institute of Experimental Immunology, University of Zurich, 8057 Zurich, Switzerland
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Abstract
The microbiota plays an integral role in shaping physical and functional aspects of the skin. While a healthy microbiota contributes to the maintenance of immune homeostasis, dysbiosis can result in the development of diverse skin pathologies. This dichotomous feature of the skin microbiota holds true not only for bacteria, but also for fungi that colonize the skin. As such, the yeast Malassezia, which is by far the most abundant component of the skin mycobiota, is associated with a variety of skin disorders, of which some can be chronic and severe and have a significant impact on the quality of life of those affected. Understanding the causative relationship between Malassezia and the development of such skin disorders requires in-depth knowledge of the mechanism by which the immune system interacts with and responds to the fungus. In this review, we will discuss recent advances in our understanding of the immune response to Malassezia and how the implicated cells and cytokine pathways prevent uncontrolled fungal growth to maintain commensalism in the mammalian skin. We also review how the antifungal response is currently thought to affect the development and severity of inflammatory disorders of the skin and at distant sites.
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Affiliation(s)
- Florian Sparber
- Section of Immunology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Fiorella Ruchti
- Section of Immunology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Salomé LeibundGut-Landmann
- Section of Immunology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
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7
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Sparber F, De Gregorio C, Steckholzer S, Ferreira FM, Dolowschiak T, Ruchti F, Kirchner FR, Mertens S, Prinz I, Joller N, Buch T, Glatz M, Sallusto F, LeibundGut-Landmann S. The Skin Commensal Yeast Malassezia Triggers a Type 17 Response that Coordinates Anti-fungal Immunity and Exacerbates Skin Inflammation. Cell Host Microbe 2019; 25:389-403.e6. [PMID: 30870621 DOI: 10.1016/j.chom.2019.02.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/28/2018] [Accepted: 02/05/2019] [Indexed: 12/12/2022]
Abstract
Commensal fungi of the mammalian skin, such as those of the genus Malassezia, are associated with atopic dermatitis and other common inflammatory skin disorders. Understanding of the causative relationship between fungal commensalism and disease manifestation remains incomplete. By developing a murine epicutaneous infection model, we found Malassezia spp. selectively induce IL-17 and related cytokines. This response is key in preventing fungal overgrowth on the skin, as disruption of the IL-23-IL-17 axis compromises Malassezia-specific cutaneous immunity. Under conditions of impaired skin integrity, mimicking a hallmark of atopic dermatitis, the presence of Malassezia dramatically aggravates cutaneous inflammation, which again was IL-23 and IL-17 dependent. Consistently, we found a CCR6+ Th17 subset of memory T cells to be Malassezia specific in both healthy individuals and atopic dermatitis patients, whereby the latter showed enhanced frequency of these cells. Thus, the Malassezia-induced type 17 response is pivotal in orchestrating antifungal immunity and in actively promoting skin inflammation.
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Affiliation(s)
- Florian Sparber
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich 8057, Switzerland
| | - Corinne De Gregorio
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona 6500, Switzerland
| | - Simone Steckholzer
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich 8057, Switzerland
| | - Filipa M Ferreira
- Institute of Laboratory Animal Science, University of Zürich, Schlieren 8952, Switzerland
| | - Tamas Dolowschiak
- Institute of Experimental Immunology, University of Zürich, Zürich 8057, Switzerland
| | - Fiorella Ruchti
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich 8057, Switzerland
| | - Florian R Kirchner
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich 8057, Switzerland
| | - Sarah Mertens
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich 8057, Switzerland
| | - Immo Prinz
- Institute of Immunology, Hannover Medical School, Hannover 30625, Germany
| | - Nicole Joller
- Institute of Experimental Immunology, University of Zürich, Zürich 8057, Switzerland
| | - Thorsten Buch
- Institute of Laboratory Animal Science, University of Zürich, Schlieren 8952, Switzerland
| | - Martin Glatz
- Department of Dermatology, University and University Hospital of Zürich, Zürich 8091, Switzerland
| | - Federica Sallusto
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona 6500, Switzerland; Institute of Microbiology, ETH Zürich, Zürich 8093, Switzerland
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Tan HTT, Hagner S, Ruchti F, Radzikowska U, Tan G, Altunbulakli C, Eljaszewicz A, Moniuszko M, Akdis M, Akdis CA, Garn H, Sokolowska M. Tight junction, mucin, and inflammasome-related molecules are differentially expressed in eosinophilic, mixed, and neutrophilic experimental asthma in mice. Allergy 2019; 74:294-307. [PMID: 30267575 DOI: 10.1111/all.13619] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/16/2018] [Accepted: 08/29/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Asthma is a chronic respiratory disease with marked clinical and pathophysiological heterogeneity. Specific pathways are thought to be involved in the pathomechanisms of different inflammatory phenotypes of asthma; however, direct in vivo comparison has not been performed. METHODS We developed mouse models representing three different phenotypes of allergic airway inflammation-eosinophilic, mixed, and neutrophilic asthma via different methods of house dust mite sensitization and challenge. Transcriptomic analysis of the lungs, followed by the RT-PCR, western blot, and confocal microscopy, was performed. Primary human bronchial epithelial cells cultured in air-liquid interface were used to study the mechanisms revealed in the in vivo models. RESULTS By whole-genome transcriptome profiling of the lung, we found that airway tight junction (TJ), mucin, and inflammasome-related genes are differentially expressed in these distinct phenotypes. Further analysis of proteins from these families revealed that Zo-1 and Cldn18 were downregulated in all phenotypes, while increased Cldn4 expression was characteristic for neutrophilic airway inflammation. Mucins Clca1 (Gob5) and Muc5ac were upregulated in eosinophilic and even more in neutrophilic phenotype. Increased expression of inflammasome-related molecules such as Nlrp3, Nlrc4, Casp-1, and IL-1β was characteristic for neutrophilic asthma. In addition, we showed that inflammasome/Th17/neutrophilic axis cytokine-IL-1β-may transiently impair epithelial barrier function, while IL-1β and IL-17 increase mucin expressions in primary human bronchial epithelial cells. CONCLUSION Our findings suggest that differential expression of TJ, mucin, and inflammasome-related molecules in distinct inflammatory phenotypes of asthma may be linked to pathophysiology and might reflect the differences observed in the clinic.
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Affiliation(s)
- Hern-Tze Tina Tan
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
- Department of Immunology; School of Medical Sciences; Universiti Sains Malaysia; Kubang Kerian Malaysia
| | - Stefanie Hagner
- Institute of Laboratory Medicine and Pathobiochemistry; Molecular Diagnostics; Marburg Germany
- Member of the German Center for Lung Research; Marburg Germany
| | - Fiorella Ruchti
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
| | - Urszula Radzikowska
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
- Department of Regenerative Medicine and Immune Regulation; Medical University of Bialystok; Bialystok Poland
| | - Ge Tan
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
- Functional Genomics Center Zurich; ETH Zurich/University of Zurich; Zurich Switzerland
| | - Can Altunbulakli
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
| | - Andrzej Eljaszewicz
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
- Department of Regenerative Medicine and Immune Regulation; Medical University of Bialystok; Bialystok Poland
| | - Marcin Moniuszko
- Department of Regenerative Medicine and Immune Regulation; Medical University of Bialystok; Bialystok Poland
| | - Mübeccel Akdis
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
| | - Cezmi A. Akdis
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
| | - Holger Garn
- Institute of Laboratory Medicine and Pathobiochemistry; Molecular Diagnostics; Marburg Germany
- Member of the German Center for Lung Research; Marburg Germany
| | - Milena Sokolowska
- Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
- Christine Kühne-Center for Allergy Research and Education; Davos Switzerland
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9
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García-Ramírez JJ, Ruchti F, Huang H, Simmen K, Angulo A, Ghazal P. Dominance of virus over host factors in cross-species activation of human cytomegalovirus early gene expression. J Virol 2001; 75:26-35. [PMID: 11119570 PMCID: PMC113894 DOI: 10.1128/jvi.75.1.26-35.2001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Human cytomegalovirus (HCMV) exhibits a highly restricted host range. In this study, we sought to examine the relative significance of host and viral factors in activating early gene expression of the HCMV UL54 (DNA polymerase) promoter in murine cells. Appropriate activation of the UL54 promoter at early times is essential for viral DNA replication. To study how the HCMV UL54 promoter is activated in murine cells, a transgenesis system based on yeast artificial chromosomes (YACs) was established for HCMV. A 178-kb YAC, containing a subgenomic fragment of HCMV encompassing the majority of the unique long (UL) region, was constructed by homologous recombination in yeast. This HCMV YAC backbone is defective for viral growth and lacks the major immediate-early (IE) gene region, thus permitting the analysis of essential cis-acting sequences when complemented in trans. To quantitatively measure the level of gene expression, we generated HCMV YACs containing a luciferase reporter gene inserted downstream of either the UL54 promoter or, as a control for late gene expression, the UL86 promoter, which directs expression of the major capsid protein. To determine the early gene activation pathway, point mutations were introduced into the inverted repeat 1 (IR1) element of the UL54 promoter of the HCMV YAC. In the transgenesis experiments, HCMV YACs and derivatives generated in yeast were introduced into NIH 3T3 murine cells by polyethylene glycol-mediated fusion. We found that infection of YAC, but not plasmid, transgenic lines with HCMV was sufficient to fully recapitulate the UL54 expression program at early times of infection, indicating the importance of remote regulatory elements in influencing regulation of the UL54 promoter. Moreover, YACs containing a mutant IR1 in the UL54 promoter led to reduced ( approximately 30-fold) reporter gene expression levels, indicating that HCMV major IE gene activation of the UL54 promoter is fully permissive in murine cells. In comparison with HCMV, infection of YAC transgenic NIH 3T3 lines with murine cytomegalovirus (MCMV) resulted in lower (more than one order of magnitude) efficiency in activating UL54 early gene expression. MCMV is therefore not able to fully activate HCMV early gene expression, indicating the significance of virus over host determinants in the cross-species activation of key early gene promoters. Finally, these studies show that YAC transgenesis can be a useful tool in functional analysis of viral proteins and control of gene expression for large viral genomes.
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Affiliation(s)
- J J García-Ramírez
- Departments of Immunology and Molecular Biology, Division of Virology, The Scripps Research Institute, La Jolla, California 92037, USA
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Streblow DN, Soderberg-Naucler C, Vieira J, Smith P, Wakabayashi E, Ruchti F, Mattison K, Altschuler Y, Nelson JA. The human cytomegalovirus chemokine receptor US28 mediates vascular smooth muscle cell migration. Cell 1999; 99:511-20. [PMID: 10589679 DOI: 10.1016/s0092-8674(00)81539-1] [Citation(s) in RCA: 334] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Human cytomegalovirus (HCMV) infection of smooth muscle cells (SMCs) in vivo has been linked to a viral etiology of vascular disease. In this report, we demonstrate that HCMV infection of primary arterial SMCs results in significant cellular migration. Ablation of the chemokine receptor, US28, abrogates SMC migration, which is rescued only by expression of the viral homolog and not a cellular G protein-coupled receptor (GPCR). Expression of US28 in the presence of CC chemokines including RANTES or MCP-1 was sufficient to promote SMC migration by both chemokinesis and chemotaxis, which was inhibited by protein tyrosine kinase inhibitors. US28-mediated SMC migration provides a molecular basis for the correlative evidence that links HCMV to the acceleration of vascular disease.
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Affiliation(s)
- D N Streblow
- Department of Molecular Microbiology and Immunology and The Vaccine and Gene Therapy Institute Oregon Health Sciences University, Portland 97201, USA
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Jault FM, Jault JM, Ruchti F, Fortunato EA, Clark C, Corbeil J, Richman DD, Spector DH. Cytomegalovirus infection induces high levels of cyclins, phosphorylated Rb, and p53, leading to cell cycle arrest. J Virol 1995; 69:6697-704. [PMID: 7474079 PMCID: PMC189579 DOI: 10.1128/jvi.69.11.6697-6704.1995] [Citation(s) in RCA: 233] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Human cytomegalovirus (HCMV) infection stimulates cellular DNA synthesis and causes chromosomal damage. Because such events likely affect cellular proliferation, we investigated the impact of HCMV infection on key components of the cell cycle. Early after infection, HCMV induced elevated levels of cyclin E, cyclin E-associated kinase activity, and two tumor suppressor proteins, p53 and the retinoblastoma gene product (Rb). The steady-state concentration of Rb continued to rise throughout the infection, with most of the protein remaining in the highly phosphorylated form. At early times, HCMV infection also induced cyclin B accumulation, which was associated with a significant increase in mitosis-promoting factor activity as the infection progresses. In contrast, the levels of cyclin A and cyclin A-associated kinase activity increased only at late times in the infection, and the kinetics were delayed relative to those for cyclins E and B. Analysis of the cellular DNA content in the infected cells by flow cytometry showed a progressive shift of the cells from the G1 to the S and G2/M phases of the cell cycle, leading to an accumulation of aneuploid cells at late times. We propose that these HCMV-mediated perturbations result in cell cycle arrest in G2/M.
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Affiliation(s)
- F M Jault
- Department of Biology, University of California, San Diego, La Jolla 92093-0357, USA
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Altmann M, Müller PP, Wittmer B, Ruchti F, Lanker S, Trachsel H. A Saccharomyces cerevisiae homologue of mammalian translation initiation factor 4B contributes to RNA helicase activity. EMBO J 1993; 12:3997-4003. [PMID: 8404865 PMCID: PMC413682 DOI: 10.1002/j.1460-2075.1993.tb06077.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The TIF3 gene of Saccharomyces cerevisiae was cloned and sequenced. The deduced amino acid sequence shows 26% identity with the sequence of mammalian translation initiation factor eIF-4B. The TIF3 gene is not essential for growth; however, its disruption results in a slow growth and cold-sensitive phenotype. In vitro translation of total yeast RNA in an extract from a TIF3 gene-disrupted strain is reduced compared with a wild-type extract. The translational defect is more pronounced at lower temperatures and can be corrected by the addition of wild-type extract or mammalian eIF-4B, but not by addition of mutant extract. In vivo translation of beta-galactosidase reporter mRNA with varying degree of RNA secondary structure in the 5' leader region in a TIF3 gene-disrupted strain shows preferential inhibition of translation of mRNA with more stable secondary structure. This indicates that Tif3 protein is an RNA helicase or contributes to RNA helicase activity in vivo.
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Affiliation(s)
- M Altmann
- Institute of Biochemistry and Molecular Biology, University of Berne, Switzerland
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Abstract
The range of hepatitis A virus (HAV) particles generated during persistent infection of different cell lines was studied. Buoyant density and sedimentation analyses of cell extracts revealed a uniform profile of particles in all cell lines analysed except for BS-C-1 cells. The virion itself usually represented less than 50% of the total mass of virus antigen. A major portion of the antigen was associated with non-infectious, empty particles, which banded at 1.305 g/ml and 1.20 g/ml CsCl, and sedimented in sucrose gradients at 76S and 59S. Empty HAV particles were similar to those of poliovirus with respect to their physical stability and had the characteristic capsid protein content (VP0, VP1 and VP3). An additional RNA-containing particle, probably the provirion, represented only a minor species characterized by a buoyant density of 1.32 g/ml in CsCl and sedimenting at 130S.
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Affiliation(s)
- F Ruchti
- Institute of Medical Microbiology, University of Bern, Switzerland
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