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Briot J, Pons C, Foucher A, Goudounèche D, Gaudenzio N, Donovan M, Bernard D, Méchin MC, Simon M. Prolyl Endopeptidase Is Involved in Filaggrinolysis and Cornification. J Invest Dermatol 2024:S0022-202X(24)00435-4. [PMID: 38879153 DOI: 10.1016/j.jid.2024.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/18/2024] [Accepted: 04/26/2024] [Indexed: 08/12/2024]
Abstract
FLG is a well-known biomarker of atopic dermatitis and skin dryness. Its full proteolysis (or filaggrinolysis) produces the major constituents of the natural moisturizing factor. Some proteases/peptidases remain to be identified in this multistep process. Mining 16 omics analyses, we identified prolyl endopeptidase (PREP) as a candidate peptidase. Indirect immunofluorescence and confocal analysis demonstrated its localization in the granular and deep cornified layers, where it colocalized with FLG. Tandem mass spectroscopy and fluorescent quenching activity assays showed that PREP cleaved several synthetic peptides derived from the FLG sequence, at the carboxyl side of an internal proline. Deimination of these peptides increased PREP enzymatic efficiency. Specific inhibition of PREP in reconstructed human epidermis using benzyloxycarbonyl-pro-prolinal induced the accumulation of FLG monomers. Downregulation of PREP expression in reconstructed human epidermis using RNA interference confirmed the impact of PREP on FLG metabolism and highlighted a more general role of PREP in keratinocyte differentiation. Indeed, quantitative global proteomic, western blotting, and RT-qPCR analyses showed a strong reduction in the expression of bleomycin hydrolase, known to be involved in filaggrinolysis, and of several other actors of cornification such as loricrin. Consequently, at the functional level, the transepidermal electric resistance was drastically reduced.
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Affiliation(s)
- Julie Briot
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), University of Toulouse, INSERM UMR1291 - CNRS UMR5051, Toulouse, France
| | - Carole Pons
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), University of Toulouse, INSERM UMR1291 - CNRS UMR5051, Toulouse, France
| | - Aude Foucher
- L'Oréal Research & Innovation, Aulnay-sous-Bois, France
| | - Dominique Goudounèche
- Centre de Microscopie Electronique Appliquée à la Biologie (CMEAB), Toulouse III University, Toulouse, France
| | - Nicolas Gaudenzio
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), University of Toulouse, INSERM UMR1291 - CNRS UMR5051, Toulouse, France; Genoskin SAS, Toulouse, France
| | - Mark Donovan
- L'Oréal Research & Innovation, Aulnay-sous-Bois, France
| | | | - Marie-Claire Méchin
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), University of Toulouse, INSERM UMR1291 - CNRS UMR5051, Toulouse, France
| | - Michel Simon
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), University of Toulouse, INSERM UMR1291 - CNRS UMR5051, Toulouse, France.
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Steinbinder J, Sachslehner AP, Holthaus KB, Eckhart L. Comparative genomics of sirenians reveals evolution of filaggrin and caspase-14 upon adaptation of the epidermis to aquatic life. Sci Rep 2024; 14:9278. [PMID: 38653760 PMCID: PMC11039687 DOI: 10.1038/s41598-024-60099-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/18/2024] [Indexed: 04/25/2024] Open
Abstract
The mammalian epidermis has evolved to protect the body in a dry environment. Genes of the epidermal differentiation complex (EDC), such as FLG (filaggrin), are implicated in the barrier function of the epidermis. Here, we investigated the molecular evolution of the EDC in sirenians (manatees and dugong), which have adapted to fully aquatic life, in comparison to the EDC of terrestrial mammals and aquatic mammals of the clade Cetacea (whales and dolphins). We show that the main subtypes of EDC genes are conserved or even duplicated, like late cornified envelope (LCE) genes of the dugong, whereas specific EDC genes have undergone inactivating mutations in sirenians. FLG contains premature stop codons in the dugong, and the ortholog of human CASP14 (caspase-14), which proteolytically processes filaggrin, is pseudogenized in the same species. As FLG and CASP14 have also been lost in whales, these mutations represent convergent evolution of skin barrier genes in different lineages of aquatic mammals. In contrast to the dugong, the manatee has retained functional FLG and CASP14 genes. FLG2 (filaggrin 2) is truncated in both species of sirenians investigated. We conclude that the land-to-water transition of sirenians was associated with modifications of the epidermal barrier at the molecular level.
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Affiliation(s)
- Julia Steinbinder
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | | | | | - Leopold Eckhart
- Department of Dermatology, Medical University of Vienna, Vienna, Austria.
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3
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Santoro D, Saridomichelakis M, Eisenschenk M, Tamamoto-Mochizuki C, Hensel P, Pucheu-Haston C. Update on the skin barrier, cutaneous microbiome and host defence peptides in canine atopic dermatitis. Vet Dermatol 2024; 35:5-14. [PMID: 37990608 DOI: 10.1111/vde.13215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/23/2023]
Abstract
BACKGROUND Canine atopic dermatitis (AD) is a complex inflammatory skin disease associated with cutaneous microbiome, immunological and skin barrier alterations. This review summarises the current evidence on skin barrier defects and on cutaneous microbiome dysfunction in canine AD. OBJECTIVE To this aim, online citation databases, abstracts and proceedings from international meetings on skin barrier and cutaneous microbiome published between 2015 and 2023 were reviewed. RESULTS Since the last update on the pathogenesis of canine AD, published by the International Committee on Allergic Diseases of Animals in 2015, 49 articles have been published on skin barrier function, cutaneous/aural innate immunity and the cutaneous/aural microbiome in atopic dogs. Skin barrier dysfunction and cutaneous microbial dysbiosis are essential players in the pathogenesis of canine AD. It is still unclear if such alterations are primary or secondary to cutaneous inflammation, although some evidence supports their primary involvement in the pathogenesis of canine AD. CONCLUSION AND CLINICAL RELEVANCE Although many studies have been published since 2015, the understanding of the cutaneous host-microbe interaction is still unclear, as is the role that cutaneous dysbiosis plays in the development and/or worsening of canine AD. More studies are needed aiming to design new therapeutic approaches to restore the skin barrier, to increase and optimise the cutaneous natural defences, and to rebalance the cutaneous microbiome.
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Affiliation(s)
- Domenico Santoro
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | | | | | - Chie Tamamoto-Mochizuki
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | | | - Cherie Pucheu-Haston
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
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4
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Surbek M, Van de Steene T, Sachslehner AP, Golabi B, Griss J, Eyckerman S, Gevaert K, Eckhart L. Cornification of keratinocytes is associated with differential changes in the catalytic activity and the immunoreactivity of transglutaminase-1. Sci Rep 2023; 13:21550. [PMID: 38057394 PMCID: PMC10700374 DOI: 10.1038/s41598-023-48856-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023] Open
Abstract
Transglutaminase 1 (TGM1) plays an essential role in skin barrier formation by cross-linking proteins in differentiated keratinocytes. Here, we established a protocol for the antibody-dependent detection of TGM1 protein and the parallel detection of TGM activity. TGM1 immunoreactivity initially increased and co-localized with membrane-associated TGM activity during keratinocyte differentiation. TGM activity persisted upon further differentiation of keratinocytes, whereas TGM1 immunoreactivity was lost under standard assay conditions. Pretreatment of tissue sections with the proteases trypsin or proteinase K enabled immunodetection of TGM1 in cornified keratinocytes, indicating that removal of other proteins was a prerequisite for TGM1 immunolabeling after cornification. The increase of TGM activity and subsequent loss of TGM1 immunoreactivity could be replicated in HEK293T cells transfected with TGM1, suggesting that protein cross-linking mediated by TGM1 itself may lead to reduced recognition of TGM1 by antibodies. To screen for proteins potentially regulating TGM1, we performed Virotrap experiments and identified the CAPNS1 subunit of calpain as an interaction partner of TGM1. Treatment of keratinocytes and TGM1-transfected HEK293T cells with chemical inhibitors of calpain suppressed transglutamination. Our findings suggest that calpain contributes to the control of TGM1-mediated transglutamination and proteins cross-linked by transglutamination mask epitopes of TGM1.
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Affiliation(s)
- Marta Surbek
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Tessa Van de Steene
- VIB Center for Medical Biotechnology Center, VIB, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | | | - Bahar Golabi
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Johannes Griss
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Sven Eyckerman
- VIB Center for Medical Biotechnology Center, VIB, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology Center, VIB, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Leopold Eckhart
- Department of Dermatology, Medical University of Vienna, Vienna, Austria.
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5
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Baur R, Kashon M, Lukomska E, Weatherly LM, Shane HL, Anderson SE. Exposure to the anti-microbial chemical triclosan disrupts keratinocyte function and skin integrity in a model of reconstructed human epidermis. J Immunotoxicol 2023; 20:1-11. [PMID: 36524471 PMCID: PMC10364087 DOI: 10.1080/1547691x.2022.2148781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/11/2022] [Indexed: 12/23/2022] Open
Abstract
Triclosan is an anti-microbial chemical incorporated into products that are applied to the skin of healthcare workers. Exposure to triclosan has previously been shown to be associated with allergic disease in humans and impact the immune responses in animal models. Additionally, studies have shown that exposure to triclosan dermally activates the NLRP3 inflammasome and disrupts the skin barrier integrity in mice. The skin is the largest organ of the body and plays an important role as a physical barrier and regulator of the immune system. Alterations in the barrier and immune regulatory functions of the skin have been demonstrated to increase the risk of sensitization and development of allergic disease. In this study, the impact of triclosan exposure on the skin barrier and keratinocyte function was investigated using a model of reconstructed human epidermis. The apical surface of reconstructed human epidermis was exposed to triclosan (0.05-0.2%) once for 6, 24, or 48 h or daily for 5 consecutive days. Exposure to triclosan increased epidermal permeability and altered the expression of genes involved in formation of the skin barrier. Additionally, exposure to triclosan altered the expression patterns of several cytokines and growth factors. Together, these results suggest that exposure to triclosan impacts skin barrier integrity and function of human keratinocytes and suggests that these alterations may impact immune regulation.
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Affiliation(s)
- Rachel Baur
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Michael Kashon
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Ewa Lukomska
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Lisa M. Weatherly
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Hillary L. Shane
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Stacey E. Anderson
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
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6
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Moosbrugger-Martinz V, Leprince C, Méchin MC, Simon M, Blunder S, Gruber R, Dubrac S. Revisiting the Roles of Filaggrin in Atopic Dermatitis. Int J Mol Sci 2022; 23:5318. [PMID: 35628125 PMCID: PMC9140947 DOI: 10.3390/ijms23105318] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/03/2022] [Accepted: 05/06/2022] [Indexed: 12/31/2022] Open
Abstract
The discovery in 2006 that loss-of-function mutations in the filaggrin gene (FLG) cause ichthyosis vulgaris and can predispose to atopic dermatitis (AD) galvanized the dermatology research community and shed new light on a skin protein that was first identified in 1981. However, although outstanding work has uncovered several key functions of filaggrin in epidermal homeostasis, a comprehensive understanding of how filaggrin deficiency contributes to AD is still incomplete, including details of the upstream factors that lead to the reduced amounts of filaggrin, regardless of genotype. In this review, we re-evaluate data focusing on the roles of filaggrin in the epidermis, as well as in AD. Filaggrin is important for alignment of keratin intermediate filaments, control of keratinocyte shape, and maintenance of epidermal texture via production of water-retaining molecules. Moreover, filaggrin deficiency leads to cellular abnormalities in keratinocytes and induces subtle epidermal barrier impairment that is sufficient enough to facilitate the ingress of certain exogenous molecules into the epidermis. However, although FLG null mutations regulate skin moisture in non-lesional AD skin, filaggrin deficiency per se does not lead to the neutralization of skin surface pH or to excessive transepidermal water loss in atopic skin. Separating facts from chaff regarding the functions of filaggrin in the epidermis is necessary for the design efficacious therapies to treat dry and atopic skin.
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Affiliation(s)
- Verena Moosbrugger-Martinz
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria; (V.M.-M.); (S.B.); (R.G.)
| | - Corinne Leprince
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), Toulouse University, CNRS UMR5051, Inserm UMR1291, UPS, 31059 Toulouse, France; (C.L.); (M.-C.M.); (M.S.)
| | - Marie-Claire Méchin
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), Toulouse University, CNRS UMR5051, Inserm UMR1291, UPS, 31059 Toulouse, France; (C.L.); (M.-C.M.); (M.S.)
| | - Michel Simon
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), Toulouse University, CNRS UMR5051, Inserm UMR1291, UPS, 31059 Toulouse, France; (C.L.); (M.-C.M.); (M.S.)
| | - Stefan Blunder
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria; (V.M.-M.); (S.B.); (R.G.)
| | - Robert Gruber
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria; (V.M.-M.); (S.B.); (R.G.)
| | - Sandrine Dubrac
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria; (V.M.-M.); (S.B.); (R.G.)
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7
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Cracking the Skin Barrier: Liquid-Liquid Phase Separation Shines under the Skin. JID INNOVATIONS 2021; 1:100036. [PMID: 34909733 PMCID: PMC8659386 DOI: 10.1016/j.xjidi.2021.100036] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 12/25/2022] Open
Abstract
Central to forming and sustaining the skin’s barrier, epidermal keratinocytes (KCs) fluxing to the skin surface undergo a rapid and enigmatic transformation into flat, enucleated squames. At the crux of this transformation are intracellular keratohyalin granules (KGs) that suddenly disappear as terminally differentiating KCs transition to the cornified skin surface. Defects in KGs have long been linked to skin barrier disorders. Through the biophysical lens of liquid-liquid phase separation (LLPS), these enigmatic KGs recently emerged as liquid-like membraneless organelles whose assembly and subsequent pH-triggered disassembly drive squame formation. To stimulate future efforts toward cracking the complex process of skin barrier formation, in this review, we integrate the key concepts and foundational work spanning the fields of LLPS and epidermal biology. We review the current progress in the skin and discuss implications in the broader context of membraneless organelles across stratifying epithelia. The discovery of environmentally sensitive LLPS dynamics in the skin points to new avenues for dissecting the skin barrier and for addressing skin barrier disorders. We argue that skin and its appendages offer outstanding models to uncover LLPS-driven mechanisms in tissue biology.
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Key Words
- 3D, three-dimensional
- AD, atopic dermatitis
- CE, cornified envelope
- EDC, epidermal differentiation complex
- ER, endoplasmic reticulum
- IDP, intrinsically-disordered protein
- KC, keratinocyte
- KG, keratohyalin granule
- LCST, lower critical solution temperature
- LLPS, liquid-liquid phase separation
- PTM, post-translational modification
- TG, trichohyalin granule
- UCST, upper critical solution temperature
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8
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Baur R, Gandhi J, Marshall NB, Lukomska E, Weatherly LM, Shane HL, Hu G, Anderson SE. Dermal exposure to the immunomodulatory antimicrobial chemical triclosan alters the skin barrier integrity and microbiome in mice. Toxicol Sci 2021; 184:223-235. [PMID: 34515797 DOI: 10.1093/toxsci/kfab111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Triclosan is an antimicrobial chemical used in healthcare settings that can be absorbed through the skin. Exposure to triclosan has been positively associated with food and aeroallergy and asthma exacerbation in humans and, although not directly sensitizing, has been demonstrated to augment the allergic response in a mouse model of asthma. The skin barrier and microbiome are thought to play important roles in regulating inflammation and allergy and disruptions may contribute to development of allergic disease. To investigate potential connections of the skin barrier and microbiome with immune responses to triclosan, SKH1 mice were exposed dermally to triclosan (0.5-2%) or vehicle for up to 7 consecutive days. Exposure to 2% triclosan for 5-7 days on the skin was shown to increase trans-epidermal water loss levels. Seven days of dermal exposure to triclosan decreased filaggrin 2 and keratin 10 expression, but increased filaggrin and keratin 14 protein along with the danger signal S100a8 and interleukin-4. Dermal exposure to triclosan for 7 days also altered the alpha and beta diversity of the skin and gut microbiome. Specifically, dermal triclosan exposure increased the relative abundance of the Firmicutes family, Lachnospiraceae on the skin but decreased the abundance of Firmicutes family, Ruminococcaceae in the gut. Collectively, these results demonstrate that repeated dermal exposure to the antimicrobial chemical triclosan alters the skin barrier integrity and microbiome in mice, suggesting that these changes may contribute to the increase in allergic immune responses following dermal exposure to triclosan.
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Affiliation(s)
- Rachel Baur
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV.,Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV
| | - Jasleen Gandhi
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV
| | - Nikki B Marshall
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
| | - Ewa Lukomska
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
| | - Lisa M Weatherly
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
| | - Hillary L Shane
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
| | - Gangqing Hu
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV.,WVU Cancer Institute, West Virginia University, Morgantown, WV, 26506, USA
| | - Stacey E Anderson
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV
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9
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Shinkai Y, Kuramochi M, Miyafusa T. New Family Members of FG Repeat Proteins and Their Unexplored Roles During Phase Separation. Front Cell Dev Biol 2021; 9:708702. [PMID: 34322491 PMCID: PMC8311347 DOI: 10.3389/fcell.2021.708702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/17/2021] [Indexed: 12/26/2022] Open
Abstract
The condensation and compartmentalization of biomacromolecules in the cell are driven by the process of phase separation. The main effectors of phase separation are intrinsically disordered proteins, which include proteins with a phenylalanine-glycine (FG) repeat domain. Our understanding of the biological function of FG repeat proteins during phase separation has been mainly derived from recent research on a member of the nuclear pore complex proteins, nucleoporins containing FG repeat domain (FG-NUPs). FG-NUPs form meshwork structures by inter- and intra-molecular FG domain interactions, which confine the nucleo-cytoplasmic exchange. Whereas FG-NUPs localize in the nuclear membrane, other FG repeat proteins reside in the cytoplasm and the nucleoplasm, and the biological function of the FG repeat domain of these proteins is not well described. In the present review, we list the FG repeat proteins that are known to phase separate in the cell, and review their biological functions. We extract the unraveled features of FG repeat proteins as an activator of barrier formation and homotypic cell-cell interactions. Understanding the regulatory mechanisms of FG repeat proteins will provide a potential delivery tool for therapeutic reagents.
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Affiliation(s)
- Yoichi Shinkai
- Molecular Neurobiology Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
| | - Takamitsu Miyafusa
- Bio-System Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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10
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Igawa S, Ohzono A, Pham P, Wang Z, Nakatsuji T, Dokoshi T, Di Nardo A. Sphingosine 1-Phosphate Receptor 2 Is Central to Maintaining Epidermal Barrier Homeostasis. J Invest Dermatol 2021; 141:1188-1197.e5. [PMID: 33197483 PMCID: PMC9801230 DOI: 10.1016/j.jid.2020.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 09/04/2020] [Accepted: 09/11/2020] [Indexed: 02/07/2023]
Abstract
The outer layer of the epidermis composes the skin barrier, a sophisticated filter constituted by layers of corneocytes in a lipid matrix. The matrix lipids, especially the ceramide-generated sphingosine 1-phosphate, are the messengers that the skin barrier uses to communicate with the basal layer of the epidermis where replicating keratinocytes are located. Sphingosine 1-phosphate is a bioactive sphingolipid mediator involved in various cellular functions through S1PR1‒5, expressed by keratinocytes. We discovered that the S1pr2 absence is linked to an impairment in the skin barrier function. Although S1pr2-/- mouse skin has no difference in its phenotype and barrier function compared with that of wild-type mouse, after tape stripping, S1pr2-/- mouse showed significantly higher transepidermal water loss and required another 24 hours to normalize their transepidermal water loss levels. Moreover, after epicutaneous Staphylococcus aureus application, impaired S1pr2-/- mouse epidermal barrier function allowed deeper bacterial penetration and denser neutrophil infiltration in the dermis. Microarray and RNA sequence of S1pr2-/- mouse epidermis linked the barrier dysfunction with a decrease in FLG2 and tight junction components. In conclusion, S1pr2-/- mice have compromised skin barrier function and increased bacteria permeability, making them a suitable model for diseases that present similar characteristics, such as atopic dermatitis.
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Affiliation(s)
- Satomi Igawa
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA,Department of Dermatology, Asahikawa Medical University, Asahikawa, Japan
| | - Ayaka Ohzono
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Phoebe Pham
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Zhenping Wang
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Teruaki Nakatsuji
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Tatsuya Dokoshi
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Anna Di Nardo
- Department of Dermatology, School of Medicine, University of California, San Diego, La Jolla, USA,Corresponding author: Anna Di Nardo, Department of Dermatology, School of Medicine, University of California, San Diego, 9500 Gilman Drive #0869, La Jolla, CA 92093, Tel: 858-822-6712, Fax: 858-822-6985,
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11
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Abstract
Human filaggrin (FLG) plays a key role in epidermal barrier function, and loss-of-function mutations of its gene are primarily responsible for the development of human atopic dermatitis (AD). FLG expression is also reduced in the epidermis of atopic patients, due to the transcriptional effect of Th2 type cytokines. Canine atopic dermatitis (CAD) is a prevalent skin disease that shares many clinical and pathogenic features with its human homologue. The aim of this review is discuss current knowledge on canine filaggrin (Flg) in both healthy and atopic dogs, as compared to the human protein. Although the molecular structures of the two proteins, as deduced from the sequences of their gene, are different, their sites of expression and their proteolytic processing in the normal epidermis are similar. Concerning the expression of Flg in CAD, conflicting results have been published at the mRNA level and little accurate information is available at the protein level. It derives from a large precursor, named profilaggrin (proFLG), formed by several FLG units and stored in keratohyalin granules of the stratum granulosum. Canine and human proFLG sequences display little amino acid similarity (33% as shown using the Basic Local Alignment Search Tool (BLAST)) except at the level of the S100 homologous part of the N-terminus (75%). Genetic studies in the dog are at an early stage and are limited by the variety of breeds and the small number of cases included. Many questions remain unanswered about the involvement of Flg in CAD pathogenesis.
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Affiliation(s)
- Daniel Combarros
- UDEAR, Université de Toulouse, INSERM UPS, Toulouse, France.,Université de Toulouse, ENVT, Toulouse, France
| | - Marie-Christine Cadiergues
- UDEAR, Université de Toulouse, INSERM UPS, Toulouse, France.,Université de Toulouse, ENVT, Toulouse, France
| | - Michel Simon
- UDEAR, Université de Toulouse, INSERM UPS, Toulouse, France
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Briot J, Simon M, Méchin MC. Deimination, Intermediate Filaments and Associated Proteins. Int J Mol Sci 2020; 21:E8746. [PMID: 33228136 PMCID: PMC7699402 DOI: 10.3390/ijms21228746] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 02/07/2023] Open
Abstract
Deimination (or citrullination) is a post-translational modification catalyzed by a calcium-dependent enzyme family of five peptidylarginine deiminases (PADs). Deimination is involved in physiological processes (cell differentiation, embryogenesis, innate and adaptive immunity, etc.) and in autoimmune diseases (rheumatoid arthritis, multiple sclerosis and lupus), cancers and neurodegenerative diseases. Intermediate filaments (IF) and associated proteins (IFAP) are major substrates of PADs. Here, we focus on the effects of deimination on the polymerization and solubility properties of IF proteins and on the proteolysis and cross-linking of IFAP, to finally expose some features of interest and some limitations of citrullinomes.
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Affiliation(s)
| | | | - Marie-Claire Méchin
- UDEAR, Institut National de la Santé Et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Université Fédérale de Toulouse Midi-Pyrénées, U1056, 31059 Toulouse, France; (J.B.); (M.S.)
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Donovan M, Salamito M, Thomas-Collignon A, Simonetti L, Desbouis S, Rain JC, Formstecher E, Bernard D. Filaggrin and filaggrin 2 processing are linked together through skin aspartic acid protease activation. PLoS One 2020; 15:e0232679. [PMID: 32437351 PMCID: PMC7241785 DOI: 10.1371/journal.pone.0232679] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 04/21/2020] [Indexed: 12/16/2022] Open
Abstract
Skin aspartic acid protease (SASPase) is believed to be a key enzyme involved in filaggrin processing during epidermal terminal differentiation. Since little is known about the regulation of SASPase function, the aim of this study was to identify involved protein partners in the process. Yeast two hybrid analyses using SASPase as bait against a human reconstructed skin library identified that the N-terminal domain of filaggrin 2 binds to the N-terminal fragment of SASPase. This interaction was confirmed in reciprocal yeast two hybrid screens and by Surface Plasmon Resonance analyses. Immunohistochemical studies in human skin, using specific antibodies to SASPase and the N-terminal domain of filaggrin 2, showed that the two proteins partially co-localized to the stratum granulosum. In vitro enzymatic assays showed that the N-terminal domain of filaggrin 2 enhanced the autoactivation of SASPase to its 14 kDa active form. Taken together, the data suggest that the N-terminal domain of filaggrin 2 regulates the activation of SASPase that may be a key event upstream of filaggrin processing to natural moisturizing factors in the human epidermis.
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Affiliation(s)
- Mark Donovan
- L’Oréal Research & Innovation, Aulnay-sous-Bois, France
- * E-mail:
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Méchin MC, Takahara H, Simon M. Deimination and Peptidylarginine Deiminases in Skin Physiology and Diseases. Int J Mol Sci 2020; 21:ijms21020566. [PMID: 31952341 PMCID: PMC7014782 DOI: 10.3390/ijms21020566] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 01/06/2023] Open
Abstract
Deimination, also known as citrullination, corresponds to the conversion of the amino acid arginine, within a peptide sequence, into the non-standard amino acid citrulline. This post-translational modification is catalyzed by a family of calcium-dependent enzymes called peptidylarginine deiminases (PADs). Deimination is implicated in a growing number of physiological processes (innate and adaptive immunity, gene regulation, embryonic development, etc.) and concerns several human diseases (rheumatoid arthritis, neurodegenerative diseases, female infertility, cancer, etc.). Here, we update the involvement of PADs in both the homeostasis of skin and skin diseases. We particularly focus on keratinocyte differentiation and the epidermal barrier function, and on hair follicles. Indeed, alteration of PAD activity in the hair shaft is responsible for two hair disorders, the uncombable hair syndrome and a particular form of inflammatory scarring alopecia, mainly affecting women of African ancestry.
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Affiliation(s)
- Marie-Claire Méchin
- UDEAR, Institut National de la Santé Et de la Recherche Médicale, Université Paul Sabatier, Université de Toulouse Midi-Pyrénées, U1056, 31059 Toulouse, France;
| | - Hidenari Takahara
- University of Ibaraki, School of Agriculture, Ibaraki 300-0393, Japan;
| | - Michel Simon
- UDEAR, Institut National de la Santé Et de la Recherche Médicale, Université Paul Sabatier, Université de Toulouse Midi-Pyrénées, U1056, 31059 Toulouse, France;
- Correspondence: ; Tel.: +33-5-6115-8427
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