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Yamaji M, Ohno Y, Shimada M, Kihara A. Alteration of epidermal lipid composition as a result of deficiency in the magnesium transporter Nipal4. J Lipid Res 2024; 65:100550. [PMID: 38692573 PMCID: PMC11153242 DOI: 10.1016/j.jlr.2024.100550] [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: 02/02/2024] [Revised: 04/23/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024] Open
Abstract
Lipids in the stratum corneum play an important role in the formation of the skin permeability barrier. The causative gene for congenital ichthyosis, NIPAL4, encodes a Mg2+ transporter and is involved in increases in intracellular Mg2+ concentrations that depend on keratinocyte differentiation. However, the role of this increased Mg2+ concentration in skin barrier formation and its effect on the lipid composition of the stratum corneum has remained largely unknown. Therefore, in the present study, we performed a detailed analysis of epidermal lipids in Nipal4 KO mice via TLC and MS. Compared with WT mice, the Nipal4 KO mice showed compositional changes in many ceramide classes (including decreases in ω-O-acylceramides and increases in ω-hydroxy ceramides), together with increases in ω-hydroxy glucosylceramides, triglycerides, and free fatty acids and decreases in ω-O-acyl hydroxy fatty acids containing a linoleic acid. We also found increases in unusual ω-O-acylceramides containing oleic acid or palmitic acid in the KO mice. However, there was little change in levels of cholesterol or protein-bound ceramides. The TLC analysis showed that some unidentified lipids were increased, and the MS analysis showed that these were special ceramides called 1-O-acylceramides. These results suggest that elevated Mg2+ concentrations in differentiated keratinocytes affect the production of various lipids, resulting in the lipid composition necessary for skin barrier formation.
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Affiliation(s)
- Marino Yamaji
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yusuke Ohno
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
| | - Madoka Shimada
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Akio Kihara
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
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2
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Dubot P, Sabourdy F, Levade T. Human genetic defects of sphingolipid synthesis. J Inherit Metab Dis 2024. [PMID: 38706107 DOI: 10.1002/jimd.12745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024]
Abstract
Sphingolipids are ubiquitous lipids, present in the membranes of all cell types, the stratum corneum and the circulating lipoproteins. Autosomal recessive as well as dominant diseases due to disturbed sphingolipid biosynthesis have been identified, including defects in the synthesis of ceramides, sphingomyelins and glycosphingolipids. In many instances, these gene variants result in the loss of catalytic function of the mutated enzymes. Additional gene defects implicate the subcellular localization of the sphingolipid-synthesizing enzyme, the regulation of its activity, or even the function of a sphingolipid-transporter protein. The resulting metabolic alterations lead to two major, non-exclusive types of clinical manifestations: a neurological disease, more or less rapidly progressive, associated or not with intellectual disability, and an ichthyotic-type skin disorder. These phenotypes highlight the critical importance of sphingolipids in brain and skin development and homeostasis. The present article reviews the clinical symptoms, genetic and biochemical alterations, pathophysiological mechanisms and therapeutic options of this relatively novel group of metabolic diseases.
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Affiliation(s)
- Patricia Dubot
- Unité Mixte de Recherche INSERM 1037, CNRS 5071, Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Laboratoire de Biochimie, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
- Centre de Recherches, CHU Sainte-Justine, Université de Montréal, Montréal, Canada
| | - Frédérique Sabourdy
- Unité Mixte de Recherche INSERM 1037, CNRS 5071, Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Laboratoire de Biochimie, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Thierry Levade
- Unité Mixte de Recherche INSERM 1037, CNRS 5071, Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Laboratoire de Biochimie, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
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3
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Kim KP, Shin KO, Lee S, Yun J, Lee T, Cho Y. PNPLA1 knockdown inhibits esterification of γ-linolenic acid to ceramide 1 in differentiated keratinocytes. Biochem Biophys Res Commun 2024; 702:149618. [PMID: 38340658 DOI: 10.1016/j.bbrc.2024.149618] [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: 01/09/2024] [Revised: 01/15/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024]
Abstract
Patatin-like phospholipase domain-containing 1 (PNPLA1) is crucial in the esterification of linoleic acid (LA; 18:2n-6) to ω-hydroxy fatty acids (FA) of ceramide 1 (Cer1), the major barrier lipid of the differentiated epidermis. We previously reported that γ-linolenic acid (GLA; 18:3n-6) as well as LA is esterified to Cer1 subspecies with sphingosine (d18:1) or eicosasphingosine (d20:1) amide-linked to two different ω-hydroxy FA (30wh:0; 32wh:1). Here, we further investigated whether PNPLA1 is also responsible for esterification of GLA to these Cer1 subspecies in normal human keratinocytes (NHK). As late/terminal differentiation was induced in NHK, PNPLA1 and differentiation markers were expressed, and LA-esterified Cer1 subspecies (18:2n-6/C30wh:0 or C32wh:0/d18:1; 18:2n-6/C32wh:0/d20:1) were detected, which were further increased with LA treatment. GLA-esterified Cer1 subspecies (18:3n-6/C30wh:0 or C32wh:0/d18:1; 18:3n-6/C32wh:0/d20:1) were detected only with GLA treatment. Specific small interfering RNA-mediated knockdown of PNPLA1 (KDP) in differentiated NHK decreased levels of these LA-esterified Cer1 subspecies overall and of involucrin (IVL), a terminal differentiation marker. Moreover, KDP resulted in lesser LA/GLA responses as characterized by more significant decreases in IVL and LA/GLA-esterified Cer1 subspecies overall and an accumulation of non-esterified ω-hydroxy ceramides, their putative precursors; the decrease of 18:3n-6/C32wh:0/d18:1, the predominant GLA-esterified Cer1 subspecies, specifically paralleled the increase of C32wh:0/d18:1, its corresponding precursor. PNPLA1 is responsible for NHK terminal differentiation and also for esterification of GLA to the ω-hydroxy FA of Cer1.
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Affiliation(s)
- Kun-Pyo Kim
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-si, Republic of Korea
| | - Kyung-Oh Shin
- Department of Food Science and Nutrition, Hallym University, Chuncheon-si, Republic of Korea
| | - Sangmin Lee
- Department of Genetic Engineering, Kyung Hee University, Yongin-si, Republic of Korea
| | - Jihyeon Yun
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-si, Republic of Korea
| | - Taehoon Lee
- Department of Genetic Engineering, Kyung Hee University, Yongin-si, Republic of Korea
| | - Yunhi Cho
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-si, Republic of Korea.
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4
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Colaço-Gaspar M, Hofer P, Oberer M, Zechner R. PNPLA-mediated lipid hydrolysis and transacylation - At the intersection of catabolism and anabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159410. [PMID: 37951382 DOI: 10.1016/j.bbalip.2023.159410] [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: 07/31/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/14/2023]
Abstract
Patatin-like phospholipase domain containing proteins (PNPLAs) play diverse roles in lipid metabolism. In this review, we focus on the enzymatic properties and predicted 3D structures of PNPLA1-5. PNPLA2-4 exert both catabolic and anabolic functions. Whereas PNPLA1 is predominantly expressed in the epidermis and involved in sphingolipid biosynthesis, PNPLA2 and 4 are ubiquitously expressed and exhibit several enzymatic activities, including hydrolysis and transacylation of various (glycero-)lipid species. This review summarizes known biological roles for PNPLA-mediated hydrolysis and transacylation reactions and highlights open questions concerning their physiological function.
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Affiliation(s)
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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5
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Ohno Y, Nakamura T, Iwasaki T, Katsuyama A, Ichikawa S, Kihara A. Determining the structure of protein-bound ceramides, essential lipids for skin barrier function. iScience 2023; 26:108248. [PMID: 37965138 PMCID: PMC10641502 DOI: 10.1016/j.isci.2023.108248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/04/2023] [Accepted: 10/16/2023] [Indexed: 11/16/2023] Open
Abstract
Protein-bound ceramides, specialized ceramides covalently bound to corneocyte surface proteins, are essential for skin permeability barrier function. However, their exact structure and target amino acid residues are unknown. Here, we found that epoxy-enone (EE) ceramides, precursors of protein-bound ceramides, as well as their synthetic analog, formed stable conjugates only with Cys among nucleophilic amino acids. NMR spectroscopy revealed that the β-carbon of the enone was attached by the thiol group of Cys via a Michael addition reaction. We confirmed the presence of Cys-bound EE ceramides in mouse epidermis by mass spectrometry analysis of protease-digested epidermis samples. EE ceramides were reversibly released from protein-bound ceramides via sulfoxide elimination. We found that protein-bound ceramides with reversible release properties accounted for approximately 60% of total protein-bound ceramides, indicating that Cys-bound EE ceramides are the predominant protein-bound ceramides. Our findings provide clues to the molecular mechanism of skin barrier formation by protein-bound ceramides.
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Affiliation(s)
- Yusuke Ohno
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Tetsuya Nakamura
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Takafumi Iwasaki
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Akira Katsuyama
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Satoshi Ichikawa
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Akio Kihara
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan
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6
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Peña-Corona SI, Gutiérrez-Ruiz SC, Echeverria MDLDC, Cortés H, González-Del Carmen M, Leyva-Gómez G. Advances in the treatment of autosomal recessive congenital ichthyosis, a look towards the repositioning of drugs. Front Pharmacol 2023; 14:1274248. [PMID: 38027029 PMCID: PMC10665491 DOI: 10.3389/fphar.2023.1274248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Autosomal recessive congenital ichthyoses (ARCI) are a skin pathology due to genetic causes characterized by a variable degree of desquamation, accompanied by erythema. The degree of symptoms is variable, different altered genes are involved, and the symptoms drastically affect patients' quality of life. Topical treatments are a first-choice strategy due to their ease of application and cost; however, enteral administration of retinoids offers greater efficacy, although with certain limitations. Despite the treatment alternatives, ARCI will persist throughout life, disabling people. Therefore, the search for new treatments always remains necessary. Especially repositioning drugs could be a short-term alternative to new affordable treatments for patients. Taking advantage of extensive knowledge of known drugs or biologics could ensure more accessible and possibly lower-cost treatments. This review briefly and concisely addresses possible repositioning strategies with drugs and biologics for ichthyosis.
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Affiliation(s)
- Sheila I. Peña-Corona
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | | | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genómica, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de Mexico, Mexico
| | | | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Butala S, Mazereeuw-Hautier J, Paller AS. Ichthyosis: presentation and management. Curr Opin Pediatr 2023; 35:467-474. [PMID: 37345742 DOI: 10.1097/mop.0000000000001264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
PURPOSE OF REVIEW This review focuses on the presentation and management of ichthyoses and highlights recent advances in treatment that hold promise for better targeted therapy. RECENT FINDINGS The ichthyoses are a group of rare genetic diseases with a wide phenotypic spectrum, characterized most often by generalized hyperkeratosis and scaling with variable erythema. The highly visible scaling and frequent itch contribute to decreased quality of life. Management for ichthyosis focuses on symptomatic relief and scale reduction with emollients, keratolytics, and retinoids. Recent advances in immune profiling and genotype-phenotype mapping have increased understanding of ichthyosis and shifted focus to pathogenesis-based targeted therapies with emerging biologics, small molecular inhibitors, and gene therapy. SUMMARY This article discusses clinical assessment and genotyping to make the diagnosis of specific forms of ichthyosis, provides guidance for management, and reviews new treatment options with systemic agents.
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Affiliation(s)
- Sneha Butala
- Department of Pediatrics, Yale New Haven Health - Bridgeport Site, Bridgeport, Connecticut; Pediatric Healthcare Associates, Shelton, Connecticut, USA
| | - Juliette Mazereeuw-Hautier
- Centre for Rare Skin Diseases, Dermatology Department, Larrey Hospital, Paul Sabatier University, Toulouse, France
| | - Amy S Paller
- Departments of Dermatology and Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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8
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Lulić AM, Katalinić M. The PNPLA family of enzymes: characterisation and biological role. Arh Hig Rada Toksikol 2023; 74:75-89. [PMID: 37357879 PMCID: PMC10291501 DOI: 10.2478/aiht-2023-74-3723] [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: 02/01/2023] [Revised: 02/01/2023] [Accepted: 05/01/2023] [Indexed: 06/27/2023] Open
Abstract
This paper brings a brief review of the human patatin-like phospholipase domain-containing protein (PNPLA) family. Even though it consists of only nine members, their physiological roles and mechanisms of their catalytic activity are not fully understood. However, the results of a number of knock-out and gain- or loss-of-function research models suggest that these enzymes have an important role in maintaining the homeostasis and integrity of organelle membranes, in cell growth, signalling, cell death, and the metabolism of lipids such as triacylglycerol, phospholipids, ceramides, and retinyl esters. Research has also revealed a connection between PNPLA family member mutations or irregular catalytic activity and the development of various diseases. Here we summarise important findings published so far and discuss their structure, localisation in the cell, distribution in the tissues, specificity for substrates, and their potential physiological role, especially in view of their potential as drug targets.
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Affiliation(s)
- Ana-Marija Lulić
- Institute for Medical Research and Occupational Health, Biochemistry and Organic Analytical Chemistry Unit, Zagreb, Croatia
| | - Maja Katalinić
- Institute for Medical Research and Occupational Health, Biochemistry and Organic Analytical Chemistry Unit, Zagreb, Croatia
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9
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Meyer JM, Boeglin WE, Brash AR. Recombinant PNPLA1 catalyzes the synthesis of acylceramides and acyl acids with selective incorporation of linoleic acid. J Lipid Res 2023; 64:100379. [PMID: 37087101 PMCID: PMC10209018 DOI: 10.1016/j.jlr.2023.100379] [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: 03/09/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/24/2023] Open
Abstract
Loss-of-function mutations in patatin-like phospholipase domain-containing protein 1 (PNPLA1) cause autosomal recessive congenital ichthyosis, and altered PNPLA1 activity is implicated in the pathogenesis of atopic dermatitis and other common skin diseases. To examine the hypothesis that PNPLA1 catalyzes the synthesis of acylceramides and acyl acids, we expressed and partially purified a soluble, truncated form of PNPLA1 in Escherichia coli, (PNPLA1trun) along with the related protein PNPLA2 (ATGL, adipose triglyceride lipase) and coactivator CGI-58. Liposomal substrates were incubated with recombinant enzymes for 0.5-24 h and products analyzed by HPLC-UV and LC-MS. Using trilinolein or dilinolein substrates, PNPLA1trun, like ATGLtrun, catalyzed lipolysis and acyltransferase reactions with 2-30% conversion into linoleic acid, monolinolein, and trilinolein. CGI-58 enhanced ATGL-catalyzed lipolysis as previously reported, but transacylase activity was not enhanced with ATGL or PNPLA1. In matching the proposed activity in vivo, PNPLA1 catalyzed acyl transfer from trilinolein and dilinolein donors to omega-hydroxy ceramide, omega-hydroxy glucosylceramide, and omega-hydroxy acid acceptors to form acylceramide, glucosyl-acylceramide, and acyl acid, respectively, albeit with only ∼0.05% conversion of the substrates. Notably, in experiments comparing dilinolein vs. diolein acyl donors, PNPLA1 transferred linoleate with 3:1 selectivity over oleate into acylceramide. These results support the role for PNPLA1 in the synthesis of acylceramides and acyl acids in epidermis and suggest that the enrichment of these lipids with linoleic acid could result from the substrate selectivity of PNPLA1.
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Affiliation(s)
- Jason M Meyer
- Department of Dermatology, Vanderbilt University Medical Center, Nashville, TN, USA; Dermatology Service, Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.
| | - William E Boeglin
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Alan R Brash
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.
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10
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Sassa T, Kihara A. Involvement of ω-O-acylceramides and protein-bound ceramides in oral permeability barrier formation. Cell Rep 2023; 42:112363. [PMID: 37054712 DOI: 10.1016/j.celrep.2023.112363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 01/23/2023] [Accepted: 03/21/2023] [Indexed: 04/15/2023] Open
Abstract
The permeability barrier present in the oral cavity is critical for protection from infection. Although lipids have properties suitable for permeability barrier formation, little is known about their role in oral barrier formation. Here, we show the presence of ω-O-acylceramides (acylceramides) and protein-bound ceramides, which are essential for the formation of permeability barriers in the epidermis, in the oral mucosae (buccal and tongue mucosae), esophagus, and stomach in mice. Conditional knockout of the fatty acid elongase Elovl1, which is involved in the synthesis of ≥C24 ceramides including acylceramides and protein-bound ceramides, in the oral mucosae and esophagus causes increased pigment penetration into the mucosal epithelium of the tongue and enhanced aversive responses to capsaicin-containing water. We find acylceramides in the buccal and gingival mucosae and protein-bound ceramides in the gingival mucosa in humans. These results indicate that acylceramides and protein-bound ceramides are important for oral permeability barrier formation.
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Affiliation(s)
- Takayuki Sassa
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
| | - Akio Kihara
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
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11
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The phospholipase A 2 superfamily as a central hub of bioactive lipids and beyond. Pharmacol Ther 2023; 244:108382. [PMID: 36918102 DOI: 10.1016/j.pharmthera.2023.108382] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/13/2023]
Abstract
In essence, "phospholipase A2" (PLA2) means a group of enzymes that release fatty acids and lysophospholipids by hydrolyzing the sn-2 position of glycerophospholipids. To date, more than 50 enzymes possessing PLA2 or related lipid-metabolizing activities have been identified in mammals, and these are subdivided into several families in terms of their structures, catalytic mechanisms, tissue/cellular localizations, and evolutionary relationships. From a general viewpoint, the PLA2 superfamily has mainly been implicated in signal transduction, driving the production of a wide variety of bioactive lipid mediators. However, a growing body of evidence indicates that PLA2s also contribute to phospholipid remodeling or recycling for membrane homeostasis, fatty acid β-oxidation for energy production, and barrier lipid formation on the body surface. Accordingly, PLA2 enzymes are considered one of the key regulators of a broad range of lipid metabolism, and perturbation of specific PLA2-driven lipid pathways often disrupts tissue and cellular homeostasis and may be associated with a variety of diseases. This review covers current understanding of the physiological functions of the PLA2 superfamily, focusing particularly on the two major intracellular PLA2 families (Ca2+-dependent cytosolic PLA2s and Ca2+-independent patatin-like PLA2s) as well as other PLA2 families, based on studies using gene-manipulated mice and human diseases in combination with comprehensive lipidomics.
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12
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Role of Omega-Hydroxy Ceramides in Epidermis: Biosynthesis, Barrier Integrity and Analyzing Method. Int J Mol Sci 2023; 24:ijms24055035. [PMID: 36902463 PMCID: PMC10003399 DOI: 10.3390/ijms24055035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/19/2023] [Accepted: 02/25/2023] [Indexed: 03/08/2023] Open
Abstract
Attached to the outer surface of the corneocyte lipid envelope (CLE), omega-hydroxy ceramides (ω-OH-Cer) link to involucrin and function as lipid components of the stratum corneum (SC). The integrity of the skin barrier is highly dependent on the lipid components of SC, especially on ω-OH-Cer. Synthetic ω-OH-Cer supplementation has been utilized in clinical practice for epidermal barrier injury and related surgeries. However, the mechanism discussion and analyzing methods are not keeping pace with its clinical application. Though mass spectrometry (MS) is the primary choice for biomolecular analysis, method modifications for ω-OH-Cer identification are lacking in progress. Therefore, finding conclusions on ω-OH-Cer biological function, as well as on its identification, means it is vital to remind further researchers of how the following work should be done. This review summarizes the important role of ω-OH-Cer in epidermal barrier functions and the forming mechanism of ω-OH-Cer. Recent identification methods for ω-OH-Cer are also discussed, which could provide new inspirations for study on both ω-OH-Cer and skin care development.
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13
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Meyer JM, Vávrová K, Radner FPW, Schneider H, Dick A, Mauro TM, Elias PM. ALOX12B and PNPLA1 Have Distinct Roles in Epidermal Lipid Lamellar Organization. J Invest Dermatol 2023; 143:332-335.e4. [PMID: 36116510 DOI: 10.1016/j.jid.2022.07.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 01/27/2023]
Affiliation(s)
- Jason M Meyer
- Dermatology Service, Tennessee Valley Healthcare System, Nashville, Tennesse, USA; Department of Dermatology, Vanderbilt University Medical Center, Nashville, Tennesse, USA.
| | - Kateřina Vávrová
- Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic
| | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Holm Schneider
- Department of Pediatrics, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Angela Dick
- Department of Pediatrics, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Theodora M Mauro
- Dermatology Branch, San Francisco VA Medical Center, San Francisco, California, USA; Department of Dermatology, University of California San Francisco, San Francisco, California, USA
| | - Peter M Elias
- Dermatology Branch, San Francisco VA Medical Center, San Francisco, California, USA; Department of Dermatology, University of California San Francisco, San Francisco, California, USA
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14
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Kleuser B, Bäumer W. Sphingosine 1-Phosphate as Essential Signaling Molecule in Inflammatory Skin Diseases. Int J Mol Sci 2023; 24:ijms24021456. [PMID: 36674974 PMCID: PMC9863039 DOI: 10.3390/ijms24021456] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/04/2023] [Accepted: 01/06/2023] [Indexed: 01/13/2023] Open
Abstract
Sphingolipids are crucial molecules of the mammalian epidermis. The formation of skin-specific ceramides contributes to the formation of lipid lamellae, which are important for the protection of the epidermis from excessive water loss and protect the skin from the invasion of pathogens and the penetration of xenobiotics. In addition to being structural constituents of the epidermal layer, sphingolipids are also key signaling molecules that participate in the regulation of epidermal cells and the immune cells of the skin. While the importance of ceramides with regard to the proliferation and differentiation of skin cells has been known for a long time, it has emerged in recent years that the sphingolipid sphingosine 1-phosphate (S1P) is also involved in processes such as the proliferation and differentiation of keratinocytes. In addition, the immunomodulatory role of this sphingolipid species is becoming increasingly apparent. This is significant as S1P mediates a variety of its actions via G-protein coupled receptors. It is, therefore, not surprising that dysregulation in the signaling pathways of S1P is involved in the pathophysiological conditions of skin diseases. In the present review, the importance of S1P in skin cells, as well as the immune cells of the skin, is elaborated. In particular, the role of the molecule in inflammatory skin diseases will be discussed. This is important because interfering with S1P signaling pathways may represent an innovative option for the treatment of inflammatory skin diseases.
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Affiliation(s)
- Burkhard Kleuser
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, Königin-Luise Str. 2+4, 14195 Berlin, Germany
- Correspondence: (B.K.); (W.B.)
| | - Wolfgang Bäumer
- Department of Veterinary Medicine, Institute of Pharmacology and Toxicology, Freie Universität Berlin, Koserstr. 20, 14195 Berlin, Germany
- Correspondence: (B.K.); (W.B.)
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15
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Almazroea A, Ijaz A, Aziz A, Mushtaq Yasinzai M, Rafiullah R, Rehman FU, Daud S, Shaikh R, Ayub M, Wali A. Identification and In Silico Analysis of a Homozygous Nonsense Variant in TGM1 Gene Segregating with Congenital Ichthyosis in a Consanguineous Family. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:103. [PMID: 36676727 PMCID: PMC9866252 DOI: 10.3390/medicina59010103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/25/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023]
Abstract
Background and Objectives: Lamellar ichthyosis is a rare skin disease characterized by large, dark brown plate-like scales on the entire body surface with minimum or no erythema. This phenotype is frequently associated with a mutation in the TGM1 gene, encoding the enzyme transglutaminase 1 which plays a catalytic role in the formation of the cornified cell envelop. The present study aimed to carry out clinical and genetic characterization of the autosomal recessive lamellar ichthyosis family from Balochistan. Materials and Methods: A consanguineous family with lamellar ichthyosis was enrolled from Balochistan, Pakistan. PCR amplification of all the exons and splice site junctions of the TGM1 gene followed by Sanger sequencing was performed on the genomic DNA. The identified variant was checked by In silico prediction tools to evaluate the effect of the variant on protein. Results: Sanger sequencing identified a homozygous nonsense variant c.131G >A (p.Trp44*) in the TGM1 gene that segregated in the autosomal recessive mode of inheritance in the family. The identified variant results in premature termination of transcribed mRNA and is predicted to cause a truncated or absent translation product transglutaminase-1 (TGase-1) accompanied by loss of catalytic activity, causing a severe clinical phenotype of lamellar ichthyosis in the patients. Conclusions: Here, we report a consanguineous lamellar ichthyosis family with a homozygous nonsense variant in the TGM1 gene. The variant is predicted as pathogenic by different In silico prediction tools.
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Affiliation(s)
- Abdulhadi Almazroea
- Pediatrician, Associate Professor at College of Medicine, Taibah University, Madinah 41477, Saudi Arabia
| | - Ambreen Ijaz
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
- Department of Zoology, SBK Women’s University, Quetta 87500, Pakistan
| | - Abdul Aziz
- Department of Computer Sciences and Bioinformatics, Khushal Khan Khattak University, Karak 27200, Pakistan
| | - Muhammad Mushtaq Yasinzai
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Rafiullah Rafiullah
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Fazal Ur Rehman
- Department of Microbiology, University of Balochistan, Quetta 87550, Pakistan
| | - Shakeela Daud
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Rozeena Shaikh
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Muhammad Ayub
- Institute of Biochemistry, University of Balochistan, Quetta 87550, Pakistan
| | - Abdul Wali
- Department of Biotechnology, Faculty of Life Sciences & Informatics, BUITEMS, Quetta 87300, Pakistan
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16
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Schratter M, Lass A, Radner FPW. ABHD5-A Regulator of Lipid Metabolism Essential for Diverse Cellular Functions. Metabolites 2022; 12:1015. [PMID: 36355098 PMCID: PMC9694394 DOI: 10.3390/metabo12111015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/19/2022] [Accepted: 10/23/2022] [Indexed: 11/12/2023] Open
Abstract
The α/β-Hydrolase domain-containing protein 5 (ABHD5; also known as comparative gene identification-58, or CGI-58) is the causative gene of the Chanarin-Dorfman syndrome (CDS), a disorder mainly characterized by systemic triacylglycerol accumulation and a severe defect in skin barrier function. The clinical phenotype of CDS patients and the characterization of global and tissue-specific ABHD5-deficient mouse strains have demonstrated that ABHD5 is a crucial regulator of lipid and energy homeostasis in various tissues. Although ABHD5 lacks intrinsic hydrolase activity, it functions as a co-activating enzyme of the patatin-like phospholipase domain-containing (PNPLA) protein family that is involved in triacylglycerol and glycerophospholipid, as well as sphingolipid and retinyl ester metabolism. Moreover, ABHD5 interacts with perilipins (PLINs) and fatty acid-binding proteins (FABPs), which are important regulators of lipid homeostasis in adipose and non-adipose tissues. This review focuses on the multifaceted role of ABHD5 in modulating the function of key enzymes in lipid metabolism.
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Affiliation(s)
- Margarita Schratter
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Achim Lass
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, 8010 Graz, Austria
| | - Franz P. W. Radner
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
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17
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Yang F, Chen G. The nutritional functions of dietary sphingomyelin and its applications in food. Front Nutr 2022; 9:1002574. [PMID: 36337644 PMCID: PMC9626766 DOI: 10.3389/fnut.2022.1002574] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Sphingolipids are common structural components of cell membranes and are crucial for cell functions in physiological and pathophysiological conditions. Sphingomyelin and its metabolites, such as sphingoid bases, ceramide, ceramide-1-phosphate, and sphingosine-1-phosphate, play signaling roles in the regulation of human health. The diverse structures of sphingolipids elicit various functions in cellular membranes and signal transduction, which may affect cell growth, differentiation, apoptosis, and maintain biological activities. As nutrients, dietary sphingomyelin and its metabolites have wide applications in the food and pharmaceutical industry. In this review, we summarized the distribution, classifications, structures, digestion, absorption and metabolic pathways of sphingolipids, and discussed the nutritional functioning of sphingomyelin in chronic metabolic diseases. The possible implications of dietary sphingomyelin in the modern food preparations including dairy products and infant formula, skin improvement, delivery system and oil organogels are also evaluated. The production of endogenous sphingomyelin is linked to pathological changes in obesity, diabetes, and atherosclerosis. However, dietary supplementations of sphingomyelin and its metabolites have been shown to maintain cholesterol homeostasis and lipid metabolism, and to prevent or treat these diseases. This seemly paradoxical phenomenon shows that dietary sphingomyelin and its metabolites are candidates for food additives and functional food development for the prevention and treatment of chronic metabolic diseases in humans.
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Affiliation(s)
- Fang Yang
- School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan, China
- *Correspondence: Fang Yang,
| | - Guoxun Chen
- Department of Nutrition, The University of Tennessee, Knoxville, TN, United States
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18
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Lyu Y, Guan Y, Deliu L, Humphrey E, Frontera JK, Yang YJ, Zamler D, Kim KH, Mohanty V, Jin K, Mohanty V, Liu V, Dou J, Veillon LJ, Kumar SV, Lorenzi PL, Chen Y, McAndrews KM, Grivennikov S, Song X, Zhang J, Xi Y, Wang J, Chen K, Nagarajan P, Ge Y. KLF5 governs sphingolipid metabolism and barrier function of the skin. Genes Dev 2022; 36:gad.349662.122. [PMID: 36008138 PMCID: PMC9480852 DOI: 10.1101/gad.349662.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/15/2022] [Indexed: 01/03/2023]
Abstract
Stem cells are fundamental units of tissue remodeling whose functions are dictated by lineage-specific transcription factors. Home to epidermal stem cells and their upward-stratifying progenies, skin relies on its secretory functions to form the outermost protective barrier, of which a transcriptional orchestrator has been elusive. KLF5 is a Krüppel-like transcription factor broadly involved in development and regeneration whose lineage specificity, if any, remains unclear. Here we report KLF5 specifically marks the epidermis, and its deletion leads to skin barrier dysfunction in vivo. Lipid envelopes and secretory lamellar bodies are defective in KLF5-deficient skin, accompanied by preferential loss of complex sphingolipids. KLF5 binds to and transcriptionally regulates genes encoding rate-limiting sphingolipid metabolism enzymes. Remarkably, skin barrier defects elicited by KLF5 ablation can be rescued by dietary interventions. Finally, we found that KLF5 is widely suppressed in human diseases with disrupted epidermal secretion, and its regulation of sphingolipid metabolism is conserved in human skin. Altogether, we established KLF5 as a disease-relevant transcription factor governing sphingolipid metabolism and barrier function in the skin, likely representing a long-sought secretory lineage-defining factor across tissue types.
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Affiliation(s)
- Ying Lyu
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Yinglu Guan
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Lisa Deliu
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Ericka Humphrey
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Joanna K Frontera
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Youn Joo Yang
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Daniel Zamler
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Kun Hee Kim
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Vakul Mohanty
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Kevin Jin
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Rice University, Houston, Texas 77005, USA
| | - Vakul Mohanty
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Rice University, Houston, Texas 77005, USA
| | - Virginia Liu
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Rice University, Houston, Texas 77005, USA
| | - Jinzhuang Dou
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Lucas J Veillon
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Shwetha V Kumar
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Philip L Lorenzi
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Yang Chen
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Kathleen M McAndrews
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Sergei Grivennikov
- Department of Medicine, Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
- Department of Biomedical Sciences, Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
| | - Xingzhi Song
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jianhua Zhang
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Yuanxin Xi
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jing Wang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Ken Chen
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Priyadharsini Nagarajan
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Yejing Ge
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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19
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Inheritance of Monogenic Hereditary Skin Disease and Related Canine Breeds. Vet Sci 2022; 9:vetsci9080433. [PMID: 36006348 PMCID: PMC9412528 DOI: 10.3390/vetsci9080433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/20/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
The plasticity of the genome is an evolutionary factor in all animal species, including canines, but it can also be the origin of diseases caused by hereditary genetic mutation. Genetic changes, or mutations, that give rise to a pathology in most cases result from recessive alleles that are normally found with minority allelic frequency. The use of genetic improvement increases the consanguinity within canine breeds and, on many occasions, also increases the frequency of these recessive alleles, increasing the prevalence of these pathologies. This prevalence has been known for a long time, but mutations differ according to the canine breed. These genetic diseases, including skin diseases, or genodermatosis, which is narrowly defined as monogenic hereditary dermatosis. In this review, we focus on genodermatosis sensu estricto, i.e., monogenic, and hereditary dermatosis, in addition to the clinical features, diagnosis, pathogeny, and treatment. Specifically, this review analyzes epidermolytic and non-epidermolytic ichthyosis, junctional epidermolysis bullosa, nasal parakeratosis, mucinosis, dermoid sinus, among others, in canine breeds, such as Golden Retriever, German Pointer, Australian Shepherd, American Bulldog, Great Dane, Jack Russell Terrier, Labrador Retriever, Shar-Pei, and Rhodesian Ridgeback.
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20
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Hasbani DJ, Hamie L, Eid E, Tamer C, Abbas O, Kurban M. Treatments for Non-Syndromic Inherited Ichthyosis, Including Emergent Pathogenesis-Related Therapy. Am J Clin Dermatol 2022; 23:853-867. [PMID: 35960486 DOI: 10.1007/s40257-022-00718-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2022] [Indexed: 11/27/2022]
Abstract
The term 'inherited ichthyosis' refers to a heterogeneous group of mendelian disorders of cornification that involve the integument with varying degrees of scaling. The management of ichthyosis poses a challenge for most physicians. Treatment options proposed in the literature include moisturizers, topical keratolytics, topical and systemic vitamin D analogues, and topical and systemic retinoids; however, some of these modalities are less reliable than others. Despite the therapeutic impasse imposed by the options above, the emergence of pathogenesis-based treatments along with novel gene therapies appear promising and hold the potential to halt or even revert disorders that arise from single genetic mutations, although research is still quite lacking in this domain. Hence, this review aims to highlight the various treatment modalities available for the management of the cutaneous manifestations of non-syndromic inherited ichthyosis, with an added emphasis on pathogenesis-targeted therapies.
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Affiliation(s)
- Divina Justina Hasbani
- Department of Dermatology, American University of Beirut Medical Center, Riad El Solh/Beirut 1107 2020, P.O. Box 11-0236, Beirut, Lebanon
| | - Lamiaa Hamie
- Department of Dermatology, Division of Pediatric Dermatology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Edward Eid
- Department of Dermatology, American University of Beirut Medical Center, Riad El Solh/Beirut 1107 2020, P.O. Box 11-0236, Beirut, Lebanon
| | - Christel Tamer
- Department of Radiology, American University of Beirut, Beirut, Lebanon
| | - Ossama Abbas
- Department of Dermatology, American University of Beirut Medical Center, Riad El Solh/Beirut 1107 2020, P.O. Box 11-0236, Beirut, Lebanon
| | - Mazen Kurban
- Department of Dermatology, American University of Beirut Medical Center, Riad El Solh/Beirut 1107 2020, P.O. Box 11-0236, Beirut, Lebanon.
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon.
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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21
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PNPLA1-Mediated Acylceramide Biosynthesis and Autosomal Recessive Congenital Ichthyosis. Metabolites 2022; 12:metabo12080685. [PMID: 35893253 PMCID: PMC9332298 DOI: 10.3390/metabo12080685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/14/2022] [Accepted: 07/21/2022] [Indexed: 02/01/2023] Open
Abstract
The stratum corneum of the epidermis acts as a life-sustaining permeability barrier. Unique heterogeneous ceramides, especially ω-O-acylceramides, are key components for the formation of stable lamellar membrane structures in the stratum corneum and are essential for a vital epidermal permeability barrier. Several enzymes involved in acylceramide synthesis have been demonstrated to be associated with ichthyosis. The function of patatin-like phospholipase domain-containing protein 1 (PNPLA1) was a mystery until the finding that PNPLA1 gene mutations were involved in autosomal-recessive congenital ichthyosis (ARCI) patients, both humans and dogs. PNPLA1 plays an essential role in the biosynthesis of acylceramide as a CoA-independent transacylase. PNPLA1 gene mutations cause decreased acylceramide levels and impaired skin barrier function. More and more mutations in PNPLA1 genes have been identified in recent years. Herein, we describe the structural and functional specificity of PNPLA1, highlight its critical roles in acylceramide synthesis and skin barrier maintenance, and summarize the PNPLA1 mutations currently identified in ARCI patients.
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22
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Catlin NR, Bowman CJ, Campion SN, Lewis EM, Nowland WS, Stethem C, Cappon GD. The postnatal resolution of developmental toxicity induced by pharmacological diacylglycerol acyltransferase 2 (DGAT2) inhibition during gestation in rats. Toxicol Sci 2022; 189:225-236. [PMID: 35866640 DOI: 10.1093/toxsci/kfac077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ervogastat (PF-06865571) is a small molecule diacylglycerol acyltransferase 2 (DGAT2) inhibitor being developed for the oral treatment of non-alcoholic steatohepatitis (NASH) with liver fibrosis. DGAT2 is a key enzyme in triglyceride synthesis in tissues and in regulating energy metabolism. Fertility and developmental toxicity studies with ervogastat were conducted in female rats and rabbits. There were no effects on female rat fertility or rabbit embryo-fetal development. Administration of ervogastat to pregnant rats during organogenesis reduced fetal weight and caused higher incidences of bent bones in fetuses that were shown to resolve by postnatal day 28 and were therefore considered to be transient variations secondary to developmental delay. Extended dosing in rats through the end of gestation and lactation (pre- and post-natal development study) caused impaired skin development, reduced offspring viability and growth retardation. The spectrum of developmental effects in rats is consistent with the intended pharmacology (altered triglyceride metabolism) and the transient nature of the skeletal findings, along with the late gestational window of sensitivity for the effects on skin barrier development, reduce the concern for potential adverse developmental effects following unintended early gestational exposure to ervogastat in humans where treatment can be discontinued once pregnancy is determined.
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Affiliation(s)
- Natasha R Catlin
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
| | - Christopher J Bowman
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
| | - Sarah N Campion
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
| | - Elise M Lewis
- Charles River Laboratories, Inc, Safety Assessment, Horsham, PA, USA
| | - William S Nowland
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
| | - Christine Stethem
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
| | - Gregg D Cappon
- Drug Safety Research, Development, & Medical, Pfizer Worldwide Research & Development, Groton, CT, USA
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23
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Joosten MDW, Clabbers JMK, Jonca N, Mazereeuw-Hautier J, Gostyński AH. New developments in the molecular treatment of ichthyosis: review of the literature. Orphanet J Rare Dis 2022; 17:269. [PMID: 35840979 PMCID: PMC9287901 DOI: 10.1186/s13023-022-02430-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/30/2022] [Indexed: 11/24/2022] Open
Abstract
Ichthyosis covers a wide spectrum of diseases affecting the cornification of the skin. In recent years, new advances in understanding the pathophysiology of ichthyosis have been made. This knowledge, combined with constant development of pathogenesis-based therapies, such as protein replacement therapy and gene therapy, are rather promising for patients with inherited skin diseases. Several ongoing trials are investigating the potency of these new approaches and various studies have already been published. Furthermore, a lot of case series report that biological therapeutics are effective treatment options, mainly for Netherton syndrome and autosomal recessive congenital ichthyosis. It is expected that some of these new therapies will prove their efficacy and will be incorporated in the treatment of ichthyosis.
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Affiliation(s)
- M D W Joosten
- Department of Dermatology, The Netherlands and European Reference Network - Skin, Maastricht University Medical Center, Maastricht, The Netherlands.,GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, P. Debyelaan 25, 6229HX, Maastricht, The Netherlands
| | - J M K Clabbers
- Department of Dermatology, The Netherlands and European Reference Network - Skin, Maastricht University Medical Center, Maastricht, The Netherlands.,GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, P. Debyelaan 25, 6229HX, Maastricht, The Netherlands.,Department of Dermatology, Haga Hospital, The Hague, The Netherlands
| | - N Jonca
- Cell Biology and Cytology Laboratory, CNRS, Inserm, UPS, European Reference Network - Skin, University Hospital Center of Toulouse and Infinity, Federal Biology Institute, Toulouse University, Toulouse, France
| | - J Mazereeuw-Hautier
- Department of Dermatology, European Reference Network - Skin, University Hospital Center of Toulouse, Toulouse, France
| | - A H Gostyński
- Department of Dermatology, The Netherlands and European Reference Network - Skin, Maastricht University Medical Center, Maastricht, The Netherlands. .,GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, P. Debyelaan 25, 6229HX, Maastricht, The Netherlands.
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24
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Patel R, Santoro A, Hofer P, Tan D, Oberer M, Nelson AT, Konduri S, Siegel D, Zechner R, Saghatelian A, Kahn BB. ATGL is a biosynthetic enzyme for fatty acid esters of hydroxy fatty acids. Nature 2022; 606:968-975. [PMID: 35676490 PMCID: PMC9242854 DOI: 10.1038/s41586-022-04787-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 04/21/2022] [Indexed: 12/16/2022]
Abstract
Branched fatty acid (FA) esters of hydroxy FAs (HFAs; FAHFAs) are recently discovered lipids that are conserved from yeast to mammals1,2. A subfamily, palmitic acid esters of hydroxy stearic acids (PAHSAs), are anti-inflammatory and anti-diabetic1,3. Humans and mice with insulin resistance have lower PAHSA levels in subcutaneous adipose tissue and serum1. PAHSA administration improves glucose tolerance and insulin sensitivity and reduces inflammation in obesity, diabetes and immune-mediated diseases1,4-7. The enzyme(s) responsible for FAHFA biosynthesis in vivo remains unknown. Here we identified adipose triglyceride lipase (ATGL, also known as patatin-like phospholipase domain containing 2 (PNPLA2)) as a candidate biosynthetic enzyme for FAHFAs using chemical biology and proteomics. We discovered that recombinant ATGL uses a transacylation reaction that esterifies an HFA with a FA from triglyceride (TG) or diglyceride to produce FAHFAs. Overexpression of wild-type, but not catalytically dead, ATGL increases FAHFA biosynthesis. Chemical inhibition of ATGL or genetic deletion of Atgl inhibits FAHFA biosynthesis and reduces the levels of FAHFA and FAHFA-TG. Levels of endogenous and nascent FAHFAs and FAHFA-TGs are 80-90 per cent lower in adipose tissue of mice in which Atgl is knocked out specifically in the adipose tissue. Increasing TG levels by upregulating diacylglycerol acyltransferase (DGAT) activity promotes FAHFA biosynthesis, and decreasing DGAT activity inhibits it, reinforcing TGs as FAHFA precursors. ATGL biosynthetic transacylase activity is present in human adipose tissue underscoring its potential clinical relevance. In summary, we discovered the first, to our knowledge, biosynthetic enzyme that catalyses the formation of the FAHFA ester bond in mammals. Whereas ATGL lipase activity is well known, our data establish a paradigm shift demonstrating that ATGL transacylase activity is biologically important.
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Affiliation(s)
- Rucha Patel
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Anna Santoro
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Dan Tan
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Andrew T Nelson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla, CA, USA
| | - Srihari Konduri
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla, CA, USA
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla, CA, USA
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Barbara B Kahn
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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25
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Opálka L, Meyer JM, Ondrejčeková V, Svatošová L, Radner FPW, Vávrová K. ω-O-Acylceramides but not ω-hydroxy ceramides are required for healthy lamellar phase architecture of skin barrier lipids. J Lipid Res 2022; 63:100226. [PMID: 35568253 PMCID: PMC9192818 DOI: 10.1016/j.jlr.2022.100226] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 11/29/2022] Open
Abstract
Epidermal omega-O-acylceramides (ω-O-acylCers) are essential components of a competent skin barrier. These unusual sphingolipids with ultralong N-acyl chains contain linoleic acid esterified to the terminal hydroxyl of the N-acyl, the formation of which requires the transacylase activity of patatin-like phospholipase domain containing 1 (PNPLA1). In ichthyosis with dysfunctional PNPLA1, ω-O-acylCer levels are significantly decreased, and ω-hydroxylated Cers (ω-OHCers) accumulate. Here we explore the role of the linoleate moiety in ω-O-acylCers in the assembly of the skin lipid barrier. Ultrastructural studies of skin samples from neonatal Pnpla1+/+ and Pnpla1-/- mice showed that the linoleate moiety in ω-O-acylCers is essential for lamellar pairing in lamellar bodies, as well as for stratum corneum lipid assembly into the long periodicity lamellar phase (LPP). To further study the molecular details of ω-O-acylCer deficiency on skin barrier lipid assembly, we built in vitro lipid models composed of major stratum corneum lipid subclasses containing either ω-O-acylCer (healthy skin model), ω-OHCer (Pnpla1-/- model), or combination of the two. X-ray diffraction, infrared spectroscopy, and permeability studies indicated that ω-OHCers could not substitute for ω-O-acylCers, although in favorable conditions, they form a medium lamellar phase with a 10.8 nm-repeat distance and permeability barrier properties similar to LPP. In the absence of ω-O-acylCers, skin lipids were prone to separation into two phases with diminished barrier properties. The models combining ω-OHCers with ω-O-acylCers indicated that accumulation of ω-OHCers does not prevent ω-O-acylCer-driven lamellar stacking. These data suggest that ω-O-acylCer supplementation may be a viable therapeutic option in patients with PNPLA1 deficiency.
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Affiliation(s)
- Lukáš Opálka
- Charles University, Faculty of Pharmacy in Hradec Králové, Hradec Králové, Czech Republic
| | - Jason M Meyer
- Department of Dermatology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Veronika Ondrejčeková
- Charles University, Faculty of Pharmacy in Hradec Králové, Hradec Králové, Czech Republic
| | - Linda Svatošová
- Charles University, Faculty of Pharmacy in Hradec Králové, Hradec Králové, Czech Republic
| | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Kateřina Vávrová
- Charles University, Faculty of Pharmacy in Hradec Králové, Hradec Králové, Czech Republic.
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26
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Kato A, Ito M, Sanaki T, Okuda T, Tsuchiya N, Yoshimoto R, Yukioka H. Acsl1 is essential for skin barrier function through the activation of linoleic acid and biosynthesis of ω-O-acylceramide in mice. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159085. [PMID: 34813948 DOI: 10.1016/j.bbalip.2021.159085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/27/2021] [Accepted: 11/14/2021] [Indexed: 10/19/2022]
Abstract
The long-chain acyl-CoA synthase1 (Acsl1) is a major enzyme that converts long-chain fatty acids to acyl-CoAs. The role of Acsl1 in energy metabolism has been elucidated in the adipose tissue, heart, and skeletal muscle. Here, we demonstrate that systemic deficiency of Acsl1 caused severe skin barrier defects, leading to embryonic lethality. Acsl1 mRNA and protein are expressed in the Acsl1+/+ epidermis, which are absent in Acsl1-/- mice. In Acsl1-/- mice, epidermal ceramide [EOS] (Cer[EOS]) containing ω-O-esterified linoleic acid, a lipid essential for the skin barrier, was significantly reduced. Conversely, ω-hydroxy ceramide (Cer[OS]), a precursor of Cer[EOS], was increased. Moreover, the levels of triglyceride (TG) species containing linoleic acids were lower in Acsl1-/- mice, whereas those not containing linoleic acid were comparable to Acsl1+/+ mice. As TG is considered to work as a reservoir of linoleic acid for the biosynthesis of Cer[EOS] from Cer[OS], our results suggest that Acsl1 plays an essential role in ω-O-acylceramide synthesis by providing linoleic acid for ω-O-esterification. Therefore, our findings identified a new biological role of Acsl1 as a regulator of the skin barrier.
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Affiliation(s)
- Ayumi Kato
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan.
| | - Mana Ito
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Takao Sanaki
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Tomohiko Okuda
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Noriko Tsuchiya
- Project Management Department, Shionogi & Co., Ltd, 8F (Reception) / 9F, Nissay Yodoyabashi East, 3-13, Imabashi 3-chome, Chuo-ku, Osaka 541-0042, Japan; Research Planning Department, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Ryo Yoshimoto
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Hideo Yukioka
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825, Japan
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27
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Vietri Rudan M, Watt FM. Mammalian Epidermis: A Compendium of Lipid Functionality. Front Physiol 2022; 12:804824. [PMID: 35095565 PMCID: PMC8791442 DOI: 10.3389/fphys.2021.804824] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
Mammalian epidermis is a striking example of the role of lipids in tissue biology. In this stratified epithelium, highly specialized structures are formed that leverage the hydrophobic properties of lipids to form an impermeable barrier and protect the humid internal environment of the body from the dry outside. This is achieved through tightly regulated lipid synthesis that generates the molecular species unique to the tissue. Beyond their fundamental structural role, lipids are involved in the active protection of the body from external insults. Lipid species present on the surface of the body possess antimicrobial activity and directly contribute to shaping the commensal microbiota. Lipids belonging to a variety of classes are also involved in the signaling events that modulate the immune responses to environmental stress as well as differentiation of the epidermal keratinocytes themselves. Recently, high-resolution methods are beginning to provide evidence for the involvement of newly identified specific lipid molecules in the regulation of epidermal homeostasis. In this review we give an overview of the wide range of biological functions of mammalian epidermal lipids.
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28
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Ahmad F, Ahmed I, Alam Q, Ahmad T, Khan A, Ahmad I, Bilal M, Hayat A, Khan A, Waqas A, Rafeeq MM, Sain ZM, Umair M. Variants in the PNPLA1 Gene in Families with Autosomal Recessive Congenital Ichthyosis Reveal Clinical Significance. Mol Syndromol 2021; 12:351-361. [PMID: 34899144 DOI: 10.1159/000516943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/28/2021] [Indexed: 01/13/2023] Open
Abstract
The term autosomal recessive congenital ichthyosis (ARCI) is the subgroup of ichthyosis, which describes a highly heterogeneous group of genetic disorders of the skin characterized by cornification and defective keratinocytes differentiation associated with mutations in at least 14 genes including PNPLA1. To study the molecular basis of the Pakistani kindreds (A and B) affected by ARCI, whole-exome sequencing (WES) in the DNA samples of affected members was performed followed by Sanger sequencing of the candidate gene to hunt down the disease-causing sequence variant/s. WES data analysis led to the identification of a novel nonsense sequence variant (c.892C>T; p.Arg298*, family A) and a recurrent missense variant (c.102C>A; p.Asp34Glu, family B) in PNPLA1 mapped to the ARCI locus in chromosome 6p21.31. Validation and cosegregation analysis of the variants in the remaining family members of the respective families were confirmed by Sanger sequencing. The current investigation expands the spectrum of PNPLA1 mutations and helps establish the proper clinico-genetic diagnosis and correct genotype-phenotype correlation.
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Affiliation(s)
- Farooq Ahmad
- Department of Chemistry, Women University Swabi, Swabi, Pakistan.,Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University (QAU), Islamabad, Pakistan
| | | | - Qamre Alam
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Science, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Tanveer Ahmad
- Department of Biotechnology, Faculty of Chemical and Life Sciences, Abdul Wali Khan University (AWKUM), Mardan, Pakistan
| | - Ammara Khan
- Department of Chemistry, Women University Swabi, Swabi, Pakistan
| | - Ijaz Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University (QAU), Islamabad, Pakistan
| | - Muhammad Bilal
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University (QAU), Islamabad, Pakistan
| | - Amir Hayat
- Department Biochemistry, Abdul Wali Khan University, Mardan, Pakistan
| | - Amjad Khan
- Laboratoire d'ImmunoRhumatologie Moléculaire, Plateforme GENOMAX, INSERM UMR_S 1109, Faculté de Médecine, Fédération Hospitalo-Universitaire OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), LabEx TRANSPLANTEX, Université de Strasbourg, Strasbourg, France
| | - Ahmed Waqas
- Division of Science and Technology, Department of Zoology, University of Education Lahore, Multan Campus, Multan, Pakistan
| | - Misbahuddin M Rafeeq
- Department of Pharmacology, Faculty of Medicine, Rabigh, King Abduaziz University, Jeddah, Saudi Arabia
| | - Ziaullah M Sain
- Department of Microbiology, Faculty of Medicine, Rabigh, King Abduaziz University, Jeddah, Saudi Arabia
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Science, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia.,Department of Life Sciences, School of Science, University of Management and Technology (UMT), Lahore, Pakistan
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29
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The Linoleic Acid Content of the Stratum Corneum of Ichthyotic Golden Retriever Dogs Is Reduced as Compared to Healthy Dogs and a Significant Part Is Oxidized in Both Free and Esterified Forms. Metabolites 2021; 11:metabo11120803. [PMID: 34940561 PMCID: PMC8704365 DOI: 10.3390/metabo11120803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/17/2021] [Accepted: 11/23/2021] [Indexed: 11/23/2022] Open
Abstract
Golden Retrievers may suffer from Pnpl1-related inherited ichthyosis. Our study shows that in the stratum corneum (SC) of ichthyotic dogs, linoleic acid (LA) is also present in the form of 9-keto-octadecadienoic acid (9-KODE) instead of the acylacid form as in normal dogs. The fatty acids purified from SC strips (LA, acylacids) were characterized by liquid chromatography-tandem mass spectrometry (LC-MS) and atmospheric pressure chemical ionization (APCI). Electrospray ionization (ESI) and MS2(MS/MS Tandem mass spectrum/spectra)/M3 (MS/MS/MS Tandem mass spectrum/spectra) fragmentation indicated the positions of the double bonds in 9-KODE. We showed that ichthyotic dogs have a threefold lower LA content in the form of acylacids. The MS2 fragmentation of acyl acids showed in some peaks the presenceof an ion at the m/z 279, instead of an ion at m/z 293 which is characteristic of LA. The detected variant was identified upon MS3 fragmentation as 9-keto-octadecadienoic acid (9-KODE), and the level of this keto-derivative was increased in ichthyotic dogs. We showed by the APCI that such keto forms of LA are produced from hydroperoxy-octadecadienoic acids (HpODE) upon dehydration. In conclusion, the free form of 9-KODE was detected in ichthyotic SC up to fivefold as compared to unaffected dogs, and analyses by HPLC (High performance liquid chromatography) and ESI-MS (Electrospray Ionization-Mass Spectrometry) indicated its production via dehydration of native 9-HpODE.
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30
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Mauldin EA, Elias PM. Ichthyosis and hereditary cornification disorders in dogs. Vet Dermatol 2021; 32:567-e154. [PMID: 34796560 DOI: 10.1111/vde.13033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/16/2021] [Accepted: 07/17/2021] [Indexed: 12/14/2022]
Abstract
The stratum corneum (SC), the outermost layer of the epidermis, serves a crucial role in maintaining body hydration and protection from environmental insults. When the stratum corneum is injured or when the genetic blueprints are flawed, the body is at risk of dehydration, secondary infections and allergen sensitization. Advancements in veterinary dermatology have revealed a wide gamut of disease from relatively benign to lethal that specifically arise from flawed structural proteins, enzymes or lipids needed to create the corneocytes and lipid bilayers of the SC. Some conditions closely mimic their human counterparts while others are unique to the dog. This review will focus on forms of ichthyosis in the dog.
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Affiliation(s)
- Elizabeth A Mauldin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey St, Philadelphia, PA, 19104, USA
| | - Peter M Elias
- Veterans Affairs Medical Center San Francisco, California, Department of Dermatology, University of California San Francisco, San Franciso, California, 150 Clement Street, Dermatology MS 190, San Francisco, CA, 94121, USA
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31
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Zwara A, Wertheim-Tysarowska K, Mika A. Alterations of Ultra Long-Chain Fatty Acids in Hereditary Skin Diseases-Review Article. Front Med (Lausanne) 2021; 8:730855. [PMID: 34497816 PMCID: PMC8420999 DOI: 10.3389/fmed.2021.730855] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/30/2021] [Indexed: 11/27/2022] Open
Abstract
The skin is a flexible organ that forms a barrier between the environment and the body's interior; it is involved in the immune response, in protection and regulation, and is a dynamic environment in which skin lipids play an important role in maintaining homeostasis. The different layers of the skin differ in both the composition and amount of lipids. The epidermis displays the best characteristics in this respect. The main lipids in this layer are cholesterol, fatty acids (FAs) and ceramides. FAs can occur in free form and as components of complex molecules. The most poorly characterized FAs are very long-chain fatty acids (VLCFAs) and ultra long-chain fatty acids (ULCFAs). VLCFAs and ULCFAs are among the main components of ceramides and are part of the free fatty acid (FFA) fraction. They are most abundant in the brain, liver, kidneys, and skin. VLCFAs and ULCFAs are responsible for the rigidity and impermeability of membranes, forming the mechanically and chemically strong outer layer of cell membranes. Any changes in the composition and length of the carbon chains of FAs result in a change in their melting point and therefore a change in membrane permeability. One of the factors causing a decrease in the amount of VLCFAs and ULCFAs is an improper diet. Another much more important factor is mutations in the genes which code proteins involved in the metabolism of VLCFAs and ULCFAs—regarding their elongation, their attachment to ceramides and their transformation. These mutations have their clinical consequences in the form of inborn errors in metabolism and neurodegenerative disorders, among others. Some of them are accompanied by skin symptoms such as ichthyosis and ichthyosiform erythroderma. In the following review, the structure of the skin is briefly characterized and the most important lipid components of the skin are presented. The focus is also on providing an overview of selected proteins involved in the metabolism of VLCFAs and ULCFAs in the skin.
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Affiliation(s)
- Agata Zwara
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | | | - Adriana Mika
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland
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32
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Miao H, Dong R, Zhang S, Yang L, Liu Y, Wang T. Hereditäre Ichthyose und Pilzinfektion: aktuelle Daten zu Pathogenese und Behandlungsstrategien. J Dtsch Dermatol Ges 2021; 19:341-351. [PMID: 33709589 DOI: 10.1111/ddg.14389_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/04/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Huilei Miao
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ruijia Dong
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Shiyu Zhang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lu Yang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuehua Liu
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Wang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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33
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Meyer JM, Crumrine D, Schneider H, Dick A, Schmuth M, Gruber R, Radner FPW, Grond S, Wakefield JS, Mauro TM, Elias PM. Unbound Corneocyte Lipid Envelopes in 12R-Lipoxygenase Deficiency Support a Specific Role in Lipid-Protein Cross-Linking. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:921-929. [PMID: 33607042 DOI: 10.1016/j.ajpath.2021.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 12/15/2022]
Abstract
Loss-of-function mutations in arachidonate lipoxygenase 12B (ALOX12B) are an important cause of autosomal recessive congenital ichthyosis (ARCI). 12R-lipoxygenase (12R-LOX), the protein product of ALOX12B, has been proposed to covalently bind the corneocyte lipid envelope (CLE) to the proteinaceous corneocyte envelope, thereby providing a scaffold for the assembly of barrier-providing, mature lipid lamellae. To test this hypothesis, an in-depth ultrastructural examination of CLEs was performed in ALOX12B-/- human and Alox12b-/- mouse epidermis, extracting samples with pyridine to distinguish covalently attached CLEs from unbound (ie, noncovalently bound) CLEs. ALOX12B--/- stratum corneum contained abundant pyridine-extractable (ie, unbound) CLEs, compared with normal stratum corneum. These unbound CLEs were associated with defective post-secretory lipid processing, and were specific to 12R-LOX deficiency, because they were not observed with deficiency of the related ARCI-associated proteins, patatin-like phospholipase 1 (Pnpla1) or abhydrolase domain containing 5 (Abhd5). These results suggest that 12R-LOX contributes specifically to CLE-corneocyte envelope cross-linking, which appears to be a prerequisite for post-secretory lipid processing, and provide insights into the pathogenesis of 12R-LOX deficiency in this subtype of ARCI, as well as other conditions that display a defective CLE.
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Affiliation(s)
- Jason M Meyer
- San Francisco Veterans Affairs Medical Center, Dermatology Service and UC San Francisco Department of Dermatology, San Francisco, California.
| | - Debra Crumrine
- San Francisco Veterans Affairs Medical Center, Dermatology Service, San Francisco, California
| | - Holm Schneider
- Department of Pediatrics, University of Erlangen-Nürnberg, Nürnberg, Germany
| | - Angela Dick
- Department of Pediatrics, University of Erlangen-Nürnberg, Nürnberg, Germany
| | - Matthias Schmuth
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Robert Gruber
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Susanne Grond
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Joan S Wakefield
- San Francisco Veterans Affairs Medical Center, Dermatology Service and UC San Francisco Department of Dermatology, San Francisco, California
| | - Theodora M Mauro
- San Francisco Veterans Affairs Medical Center, Dermatology Service and UC San Francisco Department of Dermatology, San Francisco, California
| | - Peter M Elias
- San Francisco Veterans Affairs Medical Center, Dermatology Service and UC San Francisco Department of Dermatology, San Francisco, California
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34
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hiPSC-Derived Epidermal Keratinocytes from Ichthyosis Patients Show Altered Expression of Cornification Markers. Int J Mol Sci 2021; 22:ijms22041785. [PMID: 33670118 PMCID: PMC7916893 DOI: 10.3390/ijms22041785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited ichthyoses represent a large heterogeneous group of skin disorders characterised by impaired epidermal barrier function and disturbed cornification. Current knowledge about disease mechanisms has been uncovered mainly through the use of mouse models or human skin organotypic models. However, most mouse lines suffer from severe epidermal barrier defects causing neonatal death and human keratinocytes have very limited proliferation ability in vitro. Therefore, the development of disease models based on patient derived human induced pluripotent stem cells (hiPSCs) is highly relevant. For this purpose, we have generated hiPSCs from patients with congenital ichthyosis, either non-syndromic autosomal recessive congenital ichthyosis (ARCI) or the ichthyosis syndrome trichothiodystrophy (TTD). hiPSCs were successfully differentiated into basal keratinocyte-like cells (hiPSC-bKs), with high expression of epidermal keratins. In the presence of higher calcium concentrations, terminal differentiation of hiPSC-bKs was induced and markers KRT1 and IVL expressed. TTD1 hiPSC-bKs showed reduced expression of FLG, SPRR2B and lipoxygenase genes. ARCI hiPSC-bKs showed more severe defects, with downregulation of several cornification genes. The application of hiPSC technology to TTD1 and ARCI demonstrates the successful generation of in vitro models mimicking the disease phenotypes, proving a valuable system both for further molecular investigations and drug development for ichthyosis patients.
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35
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Wertz PW. Lipid Metabolic Events Underlying the Formation of the Corneocyte Lipid Envelope. Skin Pharmacol Physiol 2021; 34:38-50. [PMID: 33567435 DOI: 10.1159/000513261] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/22/2020] [Indexed: 11/19/2022]
Abstract
Cornified cells of the stratum corneum have a monolayer of an unusual lipid covalently attached to the outer surface. This is referred to as the corneocyte lipid envelope (CLE). It consists of a monolayer of ω-hydroxyceramides covalently attached to the outer surface of the cornified envelope. The CLE is essential for proper barrier function of the skin and is derived from linoleate-rich acylglucosylceramides synthesized in the viable epidermis. Biosynthesis of acylglucosylceramide and its conversion to the cornified envelope is complex. Acylglucosylceramide in the bounding membrane of the lamellar granule is the precursor of the CLE. The acylglucosylceramide in the limiting membrane of the lamellar granule may be oriented with the glucosyl moiety on the inside. Conversion of the acylglucosylceramide to the CLE requires removal of the glucose by action of a glucocerebrosidase. The ester-linked fatty acid may be removed by an as yet unidentified esterase, and the resulting ω-hydroxyceramide may become ester linked to the outer surface of the cornified envelope through action of transglutaminase 1. Prior to removal of ester-linked fatty acids, linoleate is oxidized to an epoxy alcohol through action of 2 lipoxygenases. This can be further oxidized to an epoxy-enone, which can spontaneously attach to the cornified envelope through Schiff's base formation. Mutations of genes coding for enzymes involved in biosynthesis of the CLE result in ichthyosis, often accompanied by neurologic dysfunction. The CLE is recognized as essential for barrier function of skin, but many questions about details of this essentiality remain. What are the relative roles of the 2 mechanisms of lipid attachment? What is the orientation of acylglucosylceramide in the bounding membrane of lamellar granules? Some evidence supports a role for CLE as a scaffold upon which intercellular lamellae unfold, but other evidence does not support this role. There is also controversial evidence for a role in stratum corneum cohesion. Evidence is presented to suggest that covalently bound ω-hydroxyceramides serve as a reservoir for free sphingosine that can serve in communicating with the viable epidermis and act as a potent broad-acting antimicrobial at the skin surface. Many questions remain.
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36
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Yamamoto M, Sassa T, Kyono Y, Uemura H, Kugo M, Hayashi H, Imai Y, Yamanishi K, Kihara A. Comprehensive stratum corneum ceramide profiling reveals reduced acylceramides in ichthyosis patient with CERS3 mutations. J Dermatol 2021; 48:447-456. [PMID: 33492757 DOI: 10.1111/1346-8138.15725] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/04/2020] [Accepted: 11/23/2020] [Indexed: 11/27/2022]
Abstract
The stratum corneum (SC) of the epidermis acts as a skin permeability barrier, and abnormalities in SC formation lead to several skin disorders. Lipids, especially the epidermis-specific ceramide classes ω-O-acylceramides (acylceramides) and protein-bound ceramides, are essential for skin barrier formation. Ceramide synthase 3 (CERS3) is involved in the synthesis of acylceramides and protein-bound ceramides, and CERS3 mutations cause autosomal recessive congenital ichthyosis. In the present study, we measured ceramide synthase activity and performed comprehensive SC ceramide profiling in an ichthyosis patient with compound heterozygous CERS3 mutations: nonsense mutation p.Arg75* and missense mutation p.Arg229His. The activity of p.Arg75* and p.Arg229His mutant CERS3 proteins was reduced to 4% and 56%, respectively, of the wild-type protein. In the patient's SC, acylceramide levels were greatly reduced, but the levels of protein-bound ceramides remained almost unchanged. Non-acylated ceramide levels were also affected in the patient; in particular, the levels of ceramides composed of sphingosine and non-hydroxy or α-hydroxy fatty acid were substantially higher than in healthy controls. These results suggest that a reduction in acylceramide levels alone leads to ichthyosis. Although protein-bound ceramides are synthesized from acylceramides, levels of acylceramides and protein-bound ceramides are not necessarily correlated.
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Affiliation(s)
- Moe Yamamoto
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Takayuki Sassa
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yuki Kyono
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyasu Uemura
- Department of Pediatrics, Japanese Red Cross Society Himeji Hospital, Himeji, Japan
| | - Masaaki Kugo
- Department of Pediatrics, Japanese Red Cross Society Himeji Hospital, Himeji, Japan
| | - Hideki Hayashi
- Department of Dermatology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yasutomo Imai
- Department of Dermatology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Kiyofumi Yamanishi
- Department of Dermatology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Akio Kihara
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Miao H, Dong R, Zhang S, Yang L, Liu Y, Wang T. Inherited ichthyosis and fungal infection: an update on pathogenesis and treatment strategies. J Dtsch Dermatol Ges 2021; 19:341-350. [PMID: 33448147 DOI: 10.1111/ddg.14389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/04/2020] [Indexed: 12/30/2022]
Abstract
Inherited ichthyoses are a group of genodermatoses classified as either nonsyndromic or syndromic. Nonsyndromic ichthyoses and keratitis, ichthyosis and deafness (KID) syndrome predispose to fungal infection. The diagnosis and treatment of fungal infections underlying ichthyoses are challenging. In this review, we summarize reported cases of ichthyosis with fungal infection over the past 50 years. Atypical manifestations such as alopecia, papules and brittle nails occurred in patients with ichthyosis combined with fungal infection. Various pathogenic mechanisms have been implicated, including mutations of ichthyosis-related genes leading to disruption of the skin barrier via multiple pathways. Host immune disorders, including atopy and abnormal innate immunity also contribute to susceptibility. Specific fungi may escape the immune response. Extensive and recurrent fungal infections are not uncommon in patients with ichthyosis, making a cure more difficult and increasing the need for systemic antifungal therapy. Traditional and new ichthyosis treatments aiming to improve skin barrier function could help prevent fungal infection. In conclusion, the close relationship between ichthyosis and fungal infection is of vital importance in clinical practice and requires more attention from physicians. More studies are required to investigate the mechanisms and explore useful treatment strategies.
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Affiliation(s)
- Huilei Miao
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ruijia Dong
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Shiyu Zhang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lu Yang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuehua Liu
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Wang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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38
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Flora P, Ezhkova E. Regulatory mechanisms governing epidermal stem cell function during development and homeostasis. Development 2020; 147:147/22/dev194100. [PMID: 33191273 DOI: 10.1242/dev.194100] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cell divisions and cell-fate decisions require stringent regulation for proper tissue development and homeostasis. The mammalian epidermis is a highly organized tissue structure that is sustained by epidermal stem cells (ESCs) that balance self-renewal and cell-fate decisions to establish a protective barrier, while replacing dying cells during homeostasis and in response to injury. Extensive work over past decades has provided insights into the regulatory mechanisms that control ESC specification, self-renewal and maintenance during different stages of the lifetime of an organism. In this Review, we discuss recent findings that have furthered our understanding of key regulatory features that allow ESCs to establish a functional barrier during development and to maintain tissue homeostasis in adults.
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Affiliation(s)
- Pooja Flora
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Elena Ezhkova
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
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39
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Murakami M, Sato H, Taketomi Y. Updating Phospholipase A 2 Biology. Biomolecules 2020; 10:E1457. [PMID: 33086624 PMCID: PMC7603386 DOI: 10.3390/biom10101457] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/09/2020] [Accepted: 10/15/2020] [Indexed: 12/30/2022] Open
Abstract
The phospholipase A2 (PLA2) superfamily contains more than 50 enzymes in mammals that are subdivided into several distinct families on a structural and biochemical basis. In principle, PLA2 has the capacity to hydrolyze the sn-2 position of glycerophospholipids to release fatty acids and lysophospholipids, yet several enzymes in this superfamily catalyze other reactions rather than or in addition to the PLA2 reaction. PLA2 enzymes play crucial roles in not only the production of lipid mediators, but also membrane remodeling, bioenergetics, and body surface barrier, thereby participating in a number of biological events. Accordingly, disturbance of PLA2-regulated lipid metabolism is often associated with various diseases. This review updates the current state of understanding of the classification, enzymatic properties, and biological functions of various enzymes belonging to the PLA2 superfamily, focusing particularly on the novel roles of PLA2s in vivo.
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Affiliation(s)
- Makoto Murakami
- Laboratory of Microenvironmental and Metabolic Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan; (H.S.); (Y.T.)
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40
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Takeichi T, Hirabayashi T, Miyasaka Y, Kawamoto A, Okuno Y, Taguchi S, Tanahashi K, Murase C, Takama H, Tanaka K, Boeglin WE, Calcutt MW, Watanabe D, Kono M, Muro Y, Ishikawa J, Ohno T, Brash AR, Akiyama M. SDR9C7 catalyzes critical dehydrogenation of acylceramides for skin barrier formation. J Clin Invest 2020; 130:890-903. [PMID: 31671075 DOI: 10.1172/jci130675] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
The corneocyte lipid envelope, composed of covalently bound ceramides and fatty acids, is important to the integrity of the permeability barrier in the stratum corneum, and its absence is a prime structural defect in various skin diseases associated with defective skin barrier function. SDR9C7 encodes a short-chain dehydrogenase/reductase family 9C member 7 (SDR9C7) recently found mutated in ichthyosis. In a patient with SDR9C7 mutation and a mouse Sdr9c7-KO model, we show loss of covalent binding of epidermal ceramides to protein, a structural fault in the barrier. For reasons unresolved, protein binding requires lipoxygenase-catalyzed transformations of linoleic acid (18:2) esterified in ω-O-acylceramides. In Sdr9c7-/- epidermis, quantitative liquid chromatography-mass spectometry (LC-MS) assays revealed almost complete loss of a species of ω-O-acylceramide esterified with linoleate-9,10-trans-epoxy-11E-13-ketone; other acylceramides related to the lipoxygenase pathway were in higher abundance. Recombinant SDR9C7 catalyzed NAD+-dependent dehydrogenation of linoleate 9,10-trans-epoxy-11E-13-alcohol to the corresponding 13-ketone, while ichthyosis mutants were inactive. We propose, therefore, that the critical requirement for lipoxygenases and SDR9C7 is in producing acylceramide containing the 9,10-epoxy-11E-13-ketone, a reactive moiety known for its nonenzymatic coupling to protein. This suggests a mechanism for coupling of ceramide to protein and provides important insights into skin barrier formation and pathogenesis.
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Affiliation(s)
- Takuya Takeichi
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuya Hirabayashi
- Laboratory of Biomembrane, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yuki Miyasaka
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akane Kawamoto
- Biological Science Research Laboratories, Kao Corporation, Haga, Tochigi, Japan
| | - Yusuke Okuno
- Medical Genomics Center, Nagoya University Hospital, Nagoya, Japan
| | - Shijima Taguchi
- Division of Dermatology, Mito Kyodo General Hospital, Mito, Ibaraki, Japan
| | - Kana Tanahashi
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Chiaki Murase
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroyuki Takama
- Department of Dermatology, Aichi Medical University, Nagakute, Japan
| | - Kosei Tanaka
- Analytical Science Research Laboratories, Kao Corporation, Haga, Tochigi, Japan
| | | | - M Wade Calcutt
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Daisuke Watanabe
- Department of Dermatology, Aichi Medical University, Nagakute, Japan
| | - Michihiro Kono
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshinao Muro
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Junko Ishikawa
- Biological Science Research Laboratories, Kao Corporation, Haga, Tochigi, Japan
| | - Tamio Ohno
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Alan R Brash
- Departments of Pharmacology and Biochemistry and
| | - Masashi Akiyama
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Akiyama M. Acylceramide is a key player in skin barrier function: insight into the molecular mechanisms of skin barrier formation and ichthyosis pathogenesis. FEBS J 2020. [DOI: 10.1111/febs.15497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masashi Akiyama
- Department of Dermatology Nagoya University Graduate School of Medicine Nagoya Japan
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Molecular Mechanism of Epidermal Barrier Dysfunction as Primary Abnormalities. Int J Mol Sci 2020; 21:ijms21041194. [PMID: 32054030 PMCID: PMC7072774 DOI: 10.3390/ijms21041194] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/08/2020] [Accepted: 02/09/2020] [Indexed: 02/07/2023] Open
Abstract
Epidermal barrier integrity could be influenced by various factors involved in epidermal cell differentiation and proliferation, cell–cell adhesion, and skin lipids. Dysfunction of this barrier can cause skin disorders, including eczema. Inversely, eczema can also damage the epidermal barrier. These interactions through vicious cycles make the mechanism complicated in connection with other mechanisms, particularly immunologic responses. In this article, the molecular mechanisms concerning epidermal barrier abnormalities are reviewed in terms of the following categories: epidermal calcium gradients, filaggrin, cornified envelopes, desquamation, and skin lipids. Mechanisms linked to ichthyoses, atopic dermatitis without exacerbation or lesion, and early time of experimental irritation were included. On the other hand, the mechanism associated with epidermal barrier abnormalities resulting from preceding skin disorders was excluded. The molecular mechanism involved in epidermal barrier dysfunction has been mostly episodic. Some mechanisms have been identified in cultured cells or animal models. Nonetheless, research into the relationship between the causative molecules has been gradually increasing. Further evidence-based systematic data of target molecules and their interactions would probably be helpful for a better understanding of the molecular mechanism underlying the dysfunction of the epidermal barrier.
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Skin permeability barrier formation by the ichthyosis-causative gene FATP4 through formation of the barrier lipid ω- O-acylceramide. Proc Natl Acad Sci U S A 2020; 117:2914-2922. [PMID: 31974308 DOI: 10.1073/pnas.1917525117] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The epidermis-specific lipid acylceramide plays a pivotal role in the formation of the permeability barrier in the skin; abrogation of its synthesis causes the skin disorder ichthyosis. However, the acylceramide synthetic pathway has not yet been fully elucidated: Namely, the acyl-CoA synthetase (ACS) involved in this pathway remains to be identified. Here, we hypothesized it to be encoded by FATP4/ACSVL4, the causative gene of ichthyosis prematurity syndrome (IPS). In vitro experiments revealed that FATP4 exhibits ACS activity toward an ω-hydroxy fatty acid (FA), an intermediate of the acylceramide synthetic pathway. Fatp4 knockout (KO) mice exhibited severe skin barrier dysfunction and morphological abnormalities in the epidermis. The total amount of acylceramide in Fatp4 KO mice was reduced to ∼10% of wild-type mice. Decreased levels and shortening of chain lengths were observed in the saturated, nonacylated ceramides. FA levels were not decreased in the epidermis of Fatp4 KO mice. The expression levels of the FA elongase Elovl1 were reduced in Fatp4 KO epidermis, partly accounting for the reduction and shortening of saturated, nonacylated ceramides. A decrease in acylceramide levels was also observed in human keratinocytes with FATP4 knockdown. From these results, we conclude that skin barrier dysfunction observed in IPS patients and Fatp4 KO mice is caused mainly by reduced acylceramide production. Our findings further elucidate the molecular mechanism governing acylceramide synthesis and IPS pathology.
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44
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Li L, Liu W, Xu Y, Li M, Tang Q, Yu B, Cai R, Liu S. Targeted regions sequencing identified four novel PNPLA1 mutations in two Chinese families with autosomal recessive congenital ichthyosis. Mol Genet Genomic Med 2019; 8:e1076. [PMID: 31833240 PMCID: PMC7005637 DOI: 10.1002/mgg3.1076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/05/2019] [Accepted: 11/15/2019] [Indexed: 02/02/2023] Open
Abstract
Background Autosomal recessive congenital ichthyosis (ARCI) is a rare genetically heterogeneous cutaneous disease predominantly characterized by erythroderma, generalized abnormal scaling of the whole body and a collodion membrane at birth. Numerous causative genes have been demonstrated to be responsible for ARCI including PNPLA1 which can cause ARCI type 10. The objectives of this study are to describe clinical features of three ARCI patients from two Chinese unrelated families and to identify the underlying causative mutations. Methods Genomic DNA was extracted from peripheral venous blood obtained from the two Chinese ARCI families in Shandong province. Subsequently, targeted regions sequencing (TRS) followed by Sanger sequencing was conducted to identify and validate the likely pathogenic mutations of the ARCI families. Results Genetic analyses revealed four novel PNPLA1 variants that are predicted to be probably to lead to ARCI in three patients of two families. Patient 1 in one family was in compound heterozygous status for c.604delC/p.Arg202Glyfs*27 and c.820dupC/p.Arg274Profs*15, whereas c.738_742delinsCCCACAGATCCTGC/ p.Gly247_Tyr248delinsProGlnIleLeuHis, and c.816dupC/p.Arg274Profs*15 were found in patient 2 and 3 of the other family. In addition, these variants cosegregate in the two pedigrees and are all within highly conserved regions of the PNPLA1 protein, which indicate that the four mutations are likely pathogenic. Conclusion Our findings not only broaden the mutational spectrum of PNPLA1, but also contribute to establishing genotype–phenotype correlations for different forms of ARCI.
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Affiliation(s)
- Liangshan Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China.,Department of Clinical Laboratory, Medical College of Qingdao University, Qingdao, China
| | - Wenmiao Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yinglei Xu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Miaomiao Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Qian Tang
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Bo Yu
- Dermatological department, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Renmei Cai
- Prenatal Diagnosis Center, Qingdao Municipal Hospital, Qingdao, China
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
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45
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Murase Y, Takeichi T, Kawamoto A, Tanahashi K, Okuno Y, Takama H, Shimizu E, Ishikawa J, Ogi T, Akiyama M. Reduced stratum corneum acylceramides in autosomal recessive congenital ichthyosis with a NIPAL4 mutation. J Dermatol Sci 2019; 97:50-56. [PMID: 31836270 DOI: 10.1016/j.jdermsci.2019.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/25/2019] [Accepted: 12/01/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND NIPAL4, encoding the NIPA-like domain containing 4 protein (NIPAL4), is one of the causative genes of autosomal recessive congenital ichthyosis (ARCI). The physiological role of NIPAL4 and the pathogenetic mechanisms of ARCI caused by NIPAL4 mutations remain unclear. OBJECTIVE To clarify the changes of ceramide components in the lesional stratum corneum (SC) and the gene expression profile in the lesional skin of an ARCI patient with a novel frameshift mutation in NIPAL4. METHODS We performed ultrastructural and immunohistochemical analyses of the skin. We used RNA sequencing to determine the mRNA expression in the skin of the patient and healthy individuals. We investigated ceramide components using tape stripped SC samples from the patient. RESULTS mRNA expression profiling in the patient's skin showed significant upregulation of IL-17/TNFα-related genes (IL17C, IL36A, IL36G, S100A7A, S100A9) and psoriasis hallmark genes (VNN3, LCE3D, PLA2G4D), and significant downregulation of lipid-associated genes (GAL, HAO2, FABP7). Ceramide analysis in the patient's SC revealed amounts of CER[NS] with carbon chain-length (C) 32-52 were increased, while amounts of most acylceramide with C66:2 - C72:2 were reduced relatively to those in healthy individuals. After the retinoid treatment, CER[NS] with carbon chains C46-54, CER[EOH] and CER[EOP] increased. CONCLUSION IL-17C and IL-36 family cytokines might be involved in the pathogenetic process of ARCI with NIPAL4 mutations. Reduced amounts of the acylceramides in the SC are associated with the skin phenotype due to NIPAL4 mutations. Efficacy of the oral retinoid treatment might be due to restored amounts of CER[EOH] and CER[EOP] in the SC.
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Affiliation(s)
- Yuya Murase
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takuya Takeichi
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Akane Kawamoto
- Biological Science Research Laboratories, Kao Corporation, Haga, Japan
| | - Kana Tanahashi
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yusuke Okuno
- Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Japan
| | - Hiroyuki Takama
- Department of Dermatology, Aichi Medical University, Nagakute, Japan
| | - Eri Shimizu
- Analytical Science Research Laboratories, Kao Corporation, Haga, Tochigi, Japan
| | - Junko Ishikawa
- Biological Science Research Laboratories, Kao Corporation, Haga, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Masashi Akiyama
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Helder RWJ, Boiten WA, van Dijk R, Gooris GS, El Ghalbzouri A, Bouwstra JA. The effects of LXR agonist T0901317 and LXR antagonist GSK2033 on morphogenesis and lipid properties in full thickness skin models. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158546. [PMID: 31678517 DOI: 10.1016/j.bbalip.2019.158546] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 11/24/2022]
Abstract
Full thickness models (FTMs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). However, their stratum corneum (SC) lipid composition differs from NHS causing a reduced skin barrier. The most pronounced differences in lipid composition are a reduction in lipid chain length and increased monounsaturated lipids. The liver-X-receptor (LXR) activates the monounsaturated lipid synthesis via stearoyl-CoA desaturase-1 (SCD-1). Therefore, the aim was to improve the SC lipid synthesis of FTMs by LXR deactivation. This was achieved by supplementing culture medium with LXR antagonist GSK2033. LXR agonist T0901317 was added for comparison. Subsequently, epidermal morphogenesis, lipid composition, lipid organization and the barrier functionality of these FTMs were assessed. We demonstrate that LXR deactivation resulted in a lipid composition with increased overall chain lengths and reduced levels of monounsaturation, whereas LXR activation increased the amount of monounsaturated lipids and led to a reduction in the overall chain length. However, these changes did not affect the barrier functionality. In conclusion, LXR deactivation led to the development of FTMs with improved lipid properties, which mimic the lipid composition of NHS more closely. These novel findings may contribute to design interventions to normalize SC lipid composition of atopic dermatitis patients.
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Affiliation(s)
- Richard W J Helder
- Division of Biotherapeutics, LACDR, Leiden University, Leiden, the Netherlands.
| | - Walter A Boiten
- Division of Biotherapeutics, LACDR, Leiden University, Leiden, the Netherlands.
| | - Rianne van Dijk
- Division of Biotherapeutics, LACDR, Leiden University, Leiden, the Netherlands.
| | - Gerrit S Gooris
- Division of Biotherapeutics, LACDR, Leiden University, Leiden, the Netherlands.
| | | | - Joke A Bouwstra
- Division of Biotherapeutics, LACDR, Leiden University, Leiden, the Netherlands.
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47
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Boiten W, van Smeden J, Bouwstra J. The Cornified Envelope-Bound Ceramide Fraction Is Altered in Patients with Atopic Dermatitis. J Invest Dermatol 2019; 140:1097-1100.e4. [PMID: 31629701 DOI: 10.1016/j.jid.2019.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/29/2019] [Accepted: 09/30/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Walter Boiten
- Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Jeroen van Smeden
- Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands; Centre for Human Drug Research, Leiden, The Netherlands
| | - Joke Bouwstra
- Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
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48
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The RIPK4-IRF6 signalling axis safeguards epidermal differentiation and barrier function. Nature 2019; 574:249-253. [PMID: 31578523 DOI: 10.1038/s41586-019-1615-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/29/2019] [Indexed: 01/30/2023]
Abstract
The integrity of the mammalian epidermis depends on a balance of proliferation and differentiation in the resident population of stem cells1. The kinase RIPK4 and the transcription factor IRF6 are mutated in severe developmental syndromes in humans, and mice lacking these genes display epidermal hyperproliferation and soft-tissue fusions that result in neonatal lethality2-5. Our understanding of how these genes control epidermal differentiation is incomplete. Here we show that the role of RIPK4 in mouse development requires its kinase activity; that RIPK4 and IRF6 expressed in the epidermis regulate the same biological processes; and that the phosphorylation of IRF6 at Ser413 and Ser424 primes IRF6 for activation. Using RNA sequencing (RNA-seq), histone chromatin immunoprecipitation followed by sequencing (ChIP-seq) and assay for transposase-accessible chromatin using sequencing (ATAC-seq) of skin in wild-type and IRF6-deficient mouse embryos, we define the transcriptional programs that are regulated by IRF6 during epidermal differentiation. IRF6 was enriched at bivalent promoters, and IRF6 deficiency caused defective expression of genes that are involved in the metabolism of lipids and the formation of tight junctions. Accordingly, the lipid composition of the stratum corneum of Irf6-/- skin was abnormal, culminating in a severe defect in the function of the epidermal barrier. Collectively, our results explain how RIPK4 and IRF6 function to ensure the integrity of the epidermis and provide mechanistic insights into why developmental syndromes that are characterized by orofacial, skin and genital abnormalities result when this axis goes awry.
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Lin MH, Hsu FF, Crumrine D, Meyer J, Elias PM, Miner JH. Fatty acid transport protein 4 is required for incorporation of saturated ultralong-chain fatty acids into epidermal ceramides and monoacylglycerols. Sci Rep 2019; 9:13254. [PMID: 31519952 PMCID: PMC6744566 DOI: 10.1038/s41598-019-49684-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/29/2019] [Indexed: 01/15/2023] Open
Abstract
Fatty acid transport protein 4 (FATP4) is an acyl-CoA synthetase that is required for normal permeability barrier in mammalian skin. FATP4 (SLC27A4) mutations cause ichthyosis prematurity syndrome, a nonlethal disorder. In contrast, Fatp4-/- mice die neonatally from a defective barrier. Here we used electron microscopy and lipidomics to characterize defects in Fatp4-/- mice. Mutants showed lamellar body, corneocyte lipid envelope, and cornified envelope abnormalities. Lipidomics identified two lipids previously speculated to be present in mouse epidermis, sphingosine β-hydroxyceramide and monoacylglycerol; mutants displayed decreased proportions of these and the two ceramide classes that carry ultralong-chain, amide-linked fatty acids (FAs) thought to be critical for barrier function, unbound ω-O-acylceramide and bound ω-hydroxyceramide, the latter constituting the major component of the corneocyte lipid envelope. Other abnormalities included elevated amounts of sphingosine α-hydroxyceramide, phytosphingosine non-hydroxyceramide, and 1-O-acylceramide. Acyl chain length alterations in ceramides also suggested roles for FATP4 in esterifying saturated non-hydroxy and β-hydroxy FAs with at least 25 carbons and saturated or unsaturated ω-hydroxy FAs with at least 30 carbons to CoA. Our lipidomic analysis is the most thorough such study of the Fatp4-/- mouse skin barrier to date, providing information about how FATP4 can contribute to barrier function by regulating fatty acyl moieties in various barrier lipids.
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Affiliation(s)
- Meei-Hua Lin
- Division of Nephrology, Washington University School of Medicine, 4523 Clayton Ave., St. Louis, MO, 63110, United States
| | - Fong-Fu Hsu
- Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, 4523 Clayton Ave., St. Louis, MO, 63110, United States
| | - Debra Crumrine
- Dermatology Service, VA Medical Center and Department of Dermatology, University of California-San Francisco, 4150 Clement St., San Francisco, CA, 94121, United States
| | - Jason Meyer
- Dermatology Service, VA Medical Center and Department of Dermatology, University of California-San Francisco, 4150 Clement St., San Francisco, CA, 94121, United States
| | - Peter M Elias
- Dermatology Service, VA Medical Center and Department of Dermatology, University of California-San Francisco, 4150 Clement St., San Francisco, CA, 94121, United States
| | - Jeffrey H Miner
- Division of Nephrology, Washington University School of Medicine, 4523 Clayton Ave., St. Louis, MO, 63110, United States.
- Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, 4523 Clayton Ave., St. Louis, MO, 63110, United States.
- Department of Cell Biology and Physiology, Washington University School of Medicine, 4523 Clayton Ave., St. Louis, MO, 63110, United States.
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Severe Skin Permeability Barrier Dysfunction in Knockout Mice Deficient in a Fatty Acid ω-Hydroxylase Crucial to Acylceramide Production. J Invest Dermatol 2019; 140:319-326.e4. [PMID: 31356814 DOI: 10.1016/j.jid.2019.07.689] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/08/2019] [Accepted: 07/22/2019] [Indexed: 12/20/2022]
Abstract
The skin permeability barrier is indispensable for maintaining water inside the body and preventing the invasion of pathogens and allergens; abnormalities lead to skin disorders such as atopic dermatitis and ichthyosis. Acylceramide is an essential lipid for skin barrier formation, and CYP4F22 is a fatty acid ω-hydroxylase involved in its synthesis. Mutations in CYP4F22 cause autosomal recessive congenital ichthyosis, although the symptoms vary among mutation sites and types. Here, we generated knockout mice deficient in Cyp4f39, the mouse ortholog of human CYP4F22, to investigate the effects of completely abrogating the function of the fatty acid ω-hydroxylase involved in acylceramide production on skin barrier formation. Cyp4f39 knockout mice died within 8 hours of birth. Large increases in transepidermal water loss and penetration of a dye from outside the body were observed, indicating severe skin barrier dysfunction. Histologic analyses of the epidermis revealed impairment of lipid lamella formation, accumulation of corneodesmosomes in the stratum corneum, and persistence of periderm. In addition, lipid analyses by mass spectrometry showed almost complete loss of acylceramide and its precursor ω-hydroxy ceramide. In conclusion, our findings provide clues to the molecular mechanisms of skin barrier abnormalities and the pathogenesis of ichthyosis caused by Cyp4f39 and CYP4F22 by association.
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