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Shamaprasad P, Nădăban A, Iacovella CR, Gooris GS, Bunge AL, Bouwstra JA, McCabe C. The phase behavior of skin-barrier lipids: A combined approach of experiments and simulations. Biophys J 2024:S0006-3495(24)00477-6. [PMID: 39030908 DOI: 10.1016/j.bpj.2024.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 04/28/2024] [Accepted: 07/15/2024] [Indexed: 07/22/2024] Open
Abstract
Skin barrier function is localized in its outermost layer, the stratum corneum (SC), which is comprised of corneocyte cells embedded in an extracellular lipid matrix containing ceramides (CERs), cholesterol (CHOL), and free fatty acids (FFAs). The unique structure and composition of this lipid matrix are important for skin barrier function. In this study, experiments and molecular dynamics simulation were combined to investigate the structural properties and phase behavior of mixtures containing nonhydroxy sphingosine CER (CER NS), CHOL, and FFA. X-ray scattering for mixtures with varying CHOL levels revealed the presence of the 5.4 nm short periodicity phase in the presence of CHOL. Bilayers in coarse-grained multilayer simulations of the same compositions contained domains with thicknesses of approximately 5.3 and 5.8 nm that are associated with elevated levels, respectively, of CER sphingosine chains with CHOL, and CER acyl chains with FFA chains. The prevalence of the thicker domain increased with decreasing CHOL content. This might correspond to a phase with ∼5.8 nm spacing observed by x-rays (other details unknown) in mixtures with lower CHOL content. Scissoring and stretching frequencies from Fourier transform infrared spectroscopy (FTIR) also indicate interaction between FFA and CER acyl chains and little interaction between CER acyl and CER sphingosine chains, which requires CER molecules to adopt a predominantly extended conformation. In the simulated systems, neighbor preferences of extended CER chains align more closely with the FTIR observations than those of CERs with hairpin ceramide chains. Both FTIR and atomistic simulations of reverse mapped multilayer membranes detect a hexagonal to fluid phase transition between 65 and 80°C. These results demonstrate the utility of a collaborative experimental and simulation effort in gaining a more comprehensive understanding of SC lipid membranes.
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Affiliation(s)
- Parashara Shamaprasad
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee
| | - Andreea Nădăban
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Christopher R Iacovella
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee
| | - Gerrit S Gooris
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Annette L Bunge
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado
| | - Joke A Bouwstra
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Clare McCabe
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee; School of Engineering and Physical Science, Heriot-Watt University, Edinburgh, United Kingdom.
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2
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Fernandes E, Lopes CM, Lúcio M. Lipid Biomimetic Models as Simple Yet Complex Tools to Predict Skin Permeation and Drug-Membrane Biophysical Interactions. Pharmaceutics 2024; 16:807. [PMID: 38931927 PMCID: PMC11207520 DOI: 10.3390/pharmaceutics16060807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
The barrier function of the skin is primarily determined by its outermost layer, the Stratum Corneum (SC). The SC consists of corneocytes embedded in a lipid matrix composed mainly of ceramides, cholesterol, and free fatty acids in equimolar proportions and is organised in a complex lamellar structure with different periodicities and lateral packings. This matrix provides a diffusion pathway across the SC for bioactive compounds that are administered to the skin. In this regard, and as the skin administration route has grown in popularity, there has been an increase in the use of lipid mixtures that closely resemble the SC lipid matrix, either for a deeper biophysical understanding or for pharmaceutical and cosmetic purposes. This review focuses on a systematic analysis of the main outcomes of using lipid mixtures as SC lipid matrix models for pharmaceutical and cosmetic purposes. Thus, a methodical evaluation of the main outcomes based on the SC structure is performed, as well as the main recent developments in finding suitable new in vitro tools for permeation testing based on lipid models.
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Affiliation(s)
- Eduarda Fernandes
- CF-UM-UP—Centro de Física das Universidades do Minho e Porto, Departamento de Física, Universidade do Minho, 4710-057 Braga, Portugal
| | - Carla M. Lopes
- FFP-I3ID—Instituto de Investigação, Inovação e Desenvolvimento, FP-BHS—Biomedical and Health Sciences Research Unit, Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, 4200–150 Porto, Portugal;
- UCIBIO—Applied Molecular Biosciences Unit, MedTech–Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Marlene Lúcio
- CF-UM-UP—Centro de Física das Universidades do Minho e Porto, Departamento de Física, Universidade do Minho, 4710-057 Braga, Portugal
- CBMA—Centro de Biologia Molecular e Ambiental, Departamento de Biologia, Universidade do Minho, 4710-057 Braga, Portugal
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3
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Dwivedi A, Mazumder A, Pullmannová P, Paraskevopoulou A, Opálka L, Kováčik A, Macháček M, Jančálková P, Svačinová P, Peterlik H, Maixner J, Vávrová K. Lipid Monolayer on Cell Surface Protein Templates Functional Extracellular Lipid Assembly. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307793. [PMID: 38243890 DOI: 10.1002/smll.202307793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/18/2023] [Indexed: 01/22/2024]
Abstract
When the ancestors of men moved from aquatic habitats to the drylands, their evolutionary strategy to restrict water loss is to seal the skin surface with lipids. It is unknown how these rigid ceramide-dominated lipids with densely packed chains squeeze through narrow extracellular spaces and how they assemble into their complex multilamellar architecture. Here it is shown that the human corneocyte lipid envelope, a monolayer of ultralong covalently bound lipids on the cell surface protein, templates the functional barrier assembly by partly fluidizing and rearranging the free extracellular lipids in its vicinity during the sculpting of a functional skin lipid barrier. The lipid envelope also maintains the fluidity of the extracellular lipids during mechanical stress. This local lipid fluidization does not compromise the permeability barrier. The results provide new testable hypotheses about epidermal homeostasis and the pathophysiology underlying diseases with impaired lipid binding to corneocytes, such as congenital ichthyosis. In a broader sense, this lipoprotein-mediated fluidization of rigid (sphingo)lipid patches may also be relevant to lipid rafts and cellular signaling events and inspire new functional materials.
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Affiliation(s)
- Anupma Dwivedi
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Anisha Mazumder
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Anna Paraskevopoulou
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Lukáš Opálka
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Andrej Kováčik
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Miloslav Macháček
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Pavla Jančálková
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Petra Svačinová
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Herwig Peterlik
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Jaroslav Maixner
- Faculty of Chemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague, 16628, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
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4
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Bouwstra JA, Nădăban A, Bras W, McCabe C, Bunge A, Gooris GS. The skin barrier: An extraordinary interface with an exceptional lipid organization. Prog Lipid Res 2023; 92:101252. [PMID: 37666282 PMCID: PMC10841493 DOI: 10.1016/j.plipres.2023.101252] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/06/2023]
Abstract
The barrier function of the skin is primarily located in the stratum corneum (SC), the outermost layer of the skin. The SC is composed of dead cells with highly organized lipid lamellae in the intercellular space. As the lipid matrix forms the only continuous pathway, the lipids play an important role in the permeation of compounds through the SC. The main lipid classes are ceramides (CERs), cholesterol (CHOL) and free fatty acids (FFAs). Analysis of the SC lipid matrix is of crucial importance in understanding the skin barrier function, not only in healthy skin, but also in inflammatory skin diseases with an impaired skin barrier. In this review we provide i) a historical overview of the steps undertaken to obtain information on the lipid composition and organization in SC of healthy skin and inflammatory skin diseases, ii) information on the role CERs, CHOL and FFAs play in the lipid phase behavior of very complex lipid model systems and how this knowledge can be used to understand the deviation in lipid phase behavior in inflammatory skin diseases, iii) knowledge on the role of both, CER subclasses and chain length distribution, on lipid organization and lipid membrane permeability in complex and simple model systems with synthetic CERs, CHOL and FFAs, iv) similarity in lipid phase behavior in SC of different species and complex model systems, and vi) future directions in modulating lipid composition that is expected to improve the skin barrier in inflammatory skin diseases.
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Affiliation(s)
- Joke A Bouwstra
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
| | - Andreea Nădăban
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Wim Bras
- Chemical Sciences Division, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831, United States of America
| | - Clare McCabe
- School of Engineering & Physical Science, Heriot-Watt University, Edinburgh, Scotland, UK
| | - Annette Bunge
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, United States of America
| | - Gerrit S Gooris
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
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5
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Chen L, Xue S, Dai B, Wang Y, Zhao H. Sucrose Osmotic Self-Oscillation Drives Membrane Permeability. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7557-7565. [PMID: 37133208 DOI: 10.1021/acs.jafc.3c00794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Molecular permeation through phospholipid membranes is a fundamental biological process for small molecules. Sucrose is one of the most widely used sweeteners and a key factor in the pathogenesis of obesity and diabetes, yet a detailed understanding of its mechanism involved in permeability into phospholipid membranes is still lacking. Here, using giant unimolecular vesicles (GUVs) reconstituting membrane properties, we compared the osmotic behavior of sucrose in GUVs and HepG2 cells to explore the effect of sucrose on membrane stability in the absence of protein enhancers. The results suggested that the particle size and potential of GUVs and the cellular membrane potential changed significantly with increasing the sucrose concentration (p < 0.05). In microscopic images of cells containing GUVs and sucrose, the fluorescence intensity of vesicles was 537 ± 17.69 after 15 min, and the value was significantly higher than that of microscopic images of cells without sucrose addition (p < 0.05). These changes suggested that the permeability of the phospholipid membrane became larger under a sucrose environment. This study provides a theoretical basis for better insight on the role of sucrose in the physiological environment.
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Affiliation(s)
- Lichun Chen
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University and Research, 6708 WE Wageningen, Netherlands
| | - Songwen Xue
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Binhao Dai
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Yifei Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Huimin Zhao
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
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6
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Badhe Y, Sharma P, Gupta R, Rai B. Elucidating collective translocation of nanoparticles across the skin lipid matrix: a molecular dynamics study. NANOSCALE ADVANCES 2023; 5:1978-1989. [PMID: 36998645 PMCID: PMC10044770 DOI: 10.1039/d2na00241h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 02/02/2023] [Indexed: 06/19/2023]
Abstract
The top layer of skin, the stratum corneum, provides a formidable barrier to the skin. Nanoparticles are utilized and further explored for personal and health care applications related to the skin. In the past few years, several researchers have studied the translocation and permeation of nanoparticles of various shapes, sizes, and surface chemistry through cell membranes. Most of these studies focused on a single nanoparticle and a simple bilayer system, whereas skin has a highly complex lipid membrane architecture. Moreover, it is highly unlikely that a nanoparticle formulation applied on the skin will not have multiple nanoparticle-nanoparticle and skin-nanoparticle interactions. In this study, we have utilized coarse-grained MARTINI molecular dynamics simulations to assess the interactions of two types (bare and dodecane-thiol coated) of nanoparticles with two models (single bilayer and double bilayer) of skin lipid membranes. The nanoparticles were found to be partitioned from the water layer to the lipid membrane as an individual entity as well as in the cluster form. It was discovered that each nanoparticle reached the interior of both single bilayer and double bilayer membranes irrespective of the nanoparticle type and concentration, though coated particles were observed to efficiently traverse across the bilayer when compared with bare particles. The coated nanoparticles also created a single large cluster inside the membrane, whereas the bare nanoparticles were found in small clusters. Both the nanoparticles exhibited preferential interactions with cholesterol molecules present in the lipid membrane as compared to other lipid components of the membrane. We have also observed that the single membrane model exhibited unrealistic instability at moderate to higher concentrations of nanoparticles, and hence for translocation study, a minimum double bilayer model should be employed.
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Affiliation(s)
- Yogesh Badhe
- Physical Science Research Area, Tata Research Development and Design Centre, TCS Research 54B, Hadapsar Industrial Estate Pune - 411013 India +91-20-66086422
| | | | - Rakesh Gupta
- Physical Science Research Area, Tata Research Development and Design Centre, TCS Research 54B, Hadapsar Industrial Estate Pune - 411013 India +91-20-66086422
| | - Beena Rai
- Physical Science Research Area, Tata Research Development and Design Centre, TCS Research 54B, Hadapsar Industrial Estate Pune - 411013 India +91-20-66086422
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7
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Roy S, Ho JCS, Teo DLC, Gupta S, Nallani M. Biomimetic Stratum Corneum Liposome Models: Lamellar Organization and Permeability Studies. MEMBRANES 2023; 13:135. [PMID: 36837639 PMCID: PMC9962386 DOI: 10.3390/membranes13020135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
The stratum corneum (SC), the outer layer of the skin, plays a crucial role as a barrier protecting the underlying cells from external stress. The SC comprises three key components: ceramide (CER), free fatty acid (FFA), and cholesterol, along with small fractions of cholesterol sulfate and cholesterol ester. In order to gain a deeper understanding about the interdependence of the two major components, CER and FFA, on the organizational, structural, and functional properties of the SC layer, a library of SC lipid liposome (SCLL) models was developed by mixing CER (phytosphingosine or sphingosine), FFA (oleic acid, palmitic acid, or stearic acid), cholesterol, and cholesterol sulfate. Self-assembly of the SC lipids into lamellar phases was first confirmed by small-angle X-ray scattering. Short periodicity and long periodicity phases were identified for SCLLs containing phytosphingosines and sphingosine CERs, respectively. Furthermore, unsaturation in the CER acyl and FFA chains reduced the lipid conformational ordering and packing density of the liposomal bilayer, which were measured by differential scanning calorimetry and Fourier transform infrared spectroscopy. The introduction of unsaturation in the CER and/or FFA chains also impacted the lamellar integrity and permeability. This extensive library of SCLL models exhibiting physiologically relevant lamellar phases with defined structural and functional properties may potentially be used as a model system for screening pharmaceuticals or cosmetic agents.
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Affiliation(s)
- Susmita Roy
- Center for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University, Singapore 637553, Singapore
| | - James C. S. Ho
- Center for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University, Singapore 637553, Singapore
| | - Douglas L. C. Teo
- Center for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University, Singapore 637553, Singapore
| | - Shikhar Gupta
- Procter & Gamble International Operations SA SG Branch, Singapore 138547, Singapore
| | - Madhavan Nallani
- Center for Biomimetic Sensor Science, School of Materials Science and Engineering, Nanyang Technological University, Singapore 637553, Singapore
- ACM Biolabs Pte Ltd., Singapore 638075, Singapore
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8
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Liu Y, Ilić T, Pantelic I, Savić S, Lunter DJ. Topically applied lipid-containing emulsions based on PEGylated emulsifiers: Formulation, characterization, and evaluation of their impact on skin properties ex vivo and in vivo. Int J Pharm 2022; 626:122202. [PMID: 36122613 DOI: 10.1016/j.ijpharm.2022.122202] [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: 07/25/2022] [Revised: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 10/14/2022]
Abstract
PEGylated emulsifiers have been largely used in topical formulations for skin research. They have been a continuous study focus in our group as well. According to our previous studies, severe interruptions of the skin barrier were observed with certain types of emulsifiers. To restore the skin barrier function and counteract the effects of emulsifiers, we considered topically delivering lipids into the lipid matrix of the SC. Herein, PEG-20 cetyl ether (C20) -based oil-in-water (O/W) emulsions were developed owing to the stronger interactions of C20 with skin. The lipids containing ceramides (Cers), palmitic acids (PA), and cholesterol with different ratios and combinations were merged into the base emulsion. PEG-40 stearyl ether (S40)-based emulsion was used as a reference as S40 showed negligible impact on SC lipids. The evaluations were conducted ex vivo with confocal Raman spectroscopy (CRS) regarding the SC lipid, SC thickness, and skin penetration properties. In parallel, the in vivo irritation studies were also implemented including the transepidermal-water-loss (TEWL), skin hydration, and erythema index. The results indicated less SC lipid extraction of topically delivered lipids on ex vivo porcine skin with the addition and ratio of incorporated Cers influencing the extent of formulations counteracting the skin interruption by C20. The ex vivo penetration study showed a similar trend in drug penetration depths. In regards to the in vivo studies, TEWL was demonstrated to be suitable for differentiating the impact on skin barrier properties. The in vivo observations were generally correlated with the ex vivo results. The exact findings in this research can lead us to a better selection of applied lipid components and compositions. Future research will elucidate which type of Cer was predominantly extracted by C20, advancing future formulation development.
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Affiliation(s)
- Yali Liu
- Department of Pharmaceutical Technology, Faculty of Science, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Tanja Ilić
- Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Ivana Pantelic
- Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Snežana Savić
- Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Dominique Jasmin Lunter
- Department of Pharmaceutical Technology, Faculty of Science, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
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9
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Nădăban A, Gooris GS, Beddoes CM, Dalgliesh RM, Bouwstra JA. Phytosphingosine ceramide mainly localizes in the central layer of the unique lamellar phase of skin lipid model systems. J Lipid Res 2022; 63:100258. [PMID: 35931203 PMCID: PMC9421324 DOI: 10.1016/j.jlr.2022.100258] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/17/2022] Open
Abstract
Understanding the lipid arrangement within the skin's outermost layer, the stratum corneum (SC), is important for advancing knowledge on the skin barrier function. The SC lipid matrix consists of ceramides (CERs), cholesterol, and free fatty acids, which form unique crystalline lamellar phases, referred to as the long periodicity phase (LPP) and short periodicity phases. As the SC lipid composition is complex, lipid model systems that mimic the properties of native SC are used to study the SC lipid organization and molecular arrangement. In previous studies, such lipid models were used to determine the molecular organization in the trilayer structure of the LPP unit cell. The aim of this study was to examine the location of CER N-(tetracosanoyl)-phytosphingosine (CER NP) in the unit cell of this lamellar phase and compare its position with CER N-(tetracosanoyl)-sphingosine (CER NS). We selected CER NP as it is the most prevalent CER subclass in the human SC, and its location in the LPP is not known. Our neutron diffraction results demonstrate that the acyl chain of CER NP was positioned in the central part of the trilayer structure, with a fraction also present in the outer layers, the same location as determined for the acyl chain of CER NS. In addition, our Fourier transformed infrared spectroscopy results are in agreement with this molecular arrangement, suggesting a linear arrangement for the CER NS and CER NP. These findings provide more detailed insight into the lipid organization in the SC lipid matrix.
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Affiliation(s)
- Andreea Nădăban
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Gerrit S Gooris
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Charlotte M Beddoes
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Robert M Dalgliesh
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, United Kingdom
| | - Joke A Bouwstra
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
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10
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Shamaprasad P, Frame CO, Moore TC, Yang A, Iacovella CR, Bouwstra JA, Bunge AL, McCabe C. Using molecular simulation to understand the skin barrier. Prog Lipid Res 2022; 88:101184. [PMID: 35988796 PMCID: PMC10116345 DOI: 10.1016/j.plipres.2022.101184] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/15/2022]
Abstract
Skin's effectiveness as a barrier to permeation of water and other chemicals rests almost entirely in the outermost layer of the epidermis, the stratum corneum (SC), which consists of layers of corneocytes surrounded by highly organized lipid lamellae. As the only continuous path through the SC, transdermal permeation necessarily involves diffusion through these lipid layers. The role of the SC as a protective barrier is supported by its exceptional lipid composition consisting of ceramides (CERs), cholesterol (CHOL), and free fatty acids (FFAs) and the complete absence of phospholipids, which are present in most biological membranes. Molecular simulation, which provides molecular level detail of lipid configurations that can be connected with barrier function, has become a popular tool for studying SC lipid systems. We review this ever-increasing body of literature with the goals of (1) enabling the experimental skin community to understand, interpret and use the information generated from the simulations, (2) providing simulation experts with a solid background in the chemistry of SC lipids including the composition, structure and organization, and barrier function, and (3) presenting a state of the art picture of the field of SC lipid simulations, highlighting the difficulties and best practices for studying these systems, to encourage the generation of robust reproducible studies in the future. This review describes molecular simulation methodology and then critically examines results derived from simulations using atomistic and then coarse-grained models.
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Affiliation(s)
- Parashara Shamaprasad
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Chloe O Frame
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Timothy C Moore
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Alexander Yang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Christopher R Iacovella
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Joke A Bouwstra
- Division of BioTherapeutics, LACDR, Leiden University, 2333 CC Leiden, the Netherlands
| | - Annette L Bunge
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, United States of America
| | - Clare McCabe
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America; School of Engineering and Physical Science, Heriot-Watt University, Edinburgh, United Kingdom.
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11
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Structural and Functional Analysis of Excised Skins and Human Reconstructed Epidermis with Confocal Raman Spectroscopy and in Microfluidic Diffusion Chambers. Pharmaceutics 2022; 14:pharmaceutics14081689. [PMID: 36015315 PMCID: PMC9415586 DOI: 10.3390/pharmaceutics14081689] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/04/2022] [Accepted: 08/11/2022] [Indexed: 12/02/2022] Open
Abstract
Several ex vivo and in vitro skin models are available in the toolbox of dermatological and cosmetic research. Some of them are widely used in drug penetration testing. The excised skins show higher variability, while the in vitro skins provide more reproducible data. The aim of the current study was to compare the chemical composition of different skin models (excised rat skin, excised human skin and human-reconstructed epidermis) by measurement of ceramides, cholesterol, lactate, urea, protein and water at different depths of the tissues. The second goal was to compile a testing system, which includes a skin-on-a-chip diffusion setup and a confocal Raman spectroscopy for testing drug diffusion across the skin barrier and accumulation in the tissue models. A hydrophilic drug caffeine and the P-glycoprotein substrate quinidine were used in the study as topical cream formulations. The results indicate that although the transdermal diffusion of quinidine is lower, the skin accumulation was comparable for the two drugs. The various skin models showed different chemical compositions. The human skin was abundant in ceramides and cholesterol, while the reconstructed skin contained less water and more urea and protein. Based on these results, it can be concluded that skin-on-a-chip and confocal Raman microspectroscopy are suitable for testing drug penetration and distribution at different skin layers within an exposition window. Furthermore, obese human skin should be treated with caution for skin absorption testing due to its unbalanced composition.
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12
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Chen Y, Liao M, Ma K, Wang Z, Demé B, Penfold J, Lu JR, R P Webster J, Li P. Implications of surfactant hydrophobic chain architecture on the Surfactant-Skin lipid model interaction. J Colloid Interface Sci 2022; 608:405-415. [PMID: 34628313 DOI: 10.1016/j.jcis.2021.09.098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/15/2021] [Accepted: 09/18/2021] [Indexed: 10/20/2022]
Abstract
Although surfactants have been widely used in skin care and other related applications, our knowledge about how surfactants interact with stratum corneum (SC) lipids remains limited. This work reports how surfactants interact with a lipid SC model by neutron diffraction and molecular dynamics (MD) simulations, focusing on examining the impact of surfactant molecular architecture. The surfactant-SC mixed membrane was constructed by an equimolar mixture of ceramide/cholesterol/fatty acids and surfactant at 1% molar ratio of total lipids. The arrangements of water and surfactant molecules in the membrane were obtained through neutron scattering length density (NSLD) profiles via contrast variation method, meanwhile, MD simulation clearly demonstrated the mechanism of hydration change in the surfactant-model SC mixed membrane. No drastic difference was detected in the repeating distance of the short periodicity phase (SPP) upon adding surfactants, however, it significantly enhanced the membrane hydration and reduced the amount of phase separated crystalline cholesterol, showing a strong dependence on surfactant chain length, branching and double bond. This work clearly demonstrates how surfactant architecture affects its interaction with the SC membrane, providing useful guidance for either choosing an existing surfactant or designing a new one for surfactant-based transdermal application.
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Affiliation(s)
- Yao Chen
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Didcot, OXON, UK OX11 0QX
| | - Mingrui Liao
- Department of Physics & Astronomy, the University of Manchester, Manchester M13 9PL, UK
| | - Kun Ma
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Didcot, OXON, UK OX11 0QX
| | - Zi Wang
- School of Science, State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao 266580, China
| | - Bruno Demé
- Institut Laue-Langevin, Grenoble, France
| | - Jeff Penfold
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Didcot, OXON, UK OX11 0QX
| | - Jian R Lu
- Department of Physics & Astronomy, the University of Manchester, Manchester M13 9PL, UK
| | - John R P Webster
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Didcot, OXON, UK OX11 0QX
| | - Peixun Li
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Didcot, OXON, UK OX11 0QX.
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13
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Cholesterol Sulfate Fluidizes the Sterol Fraction of the Stratum Corneum Lipid Phase and Increases its Permeability. J Lipid Res 2022; 63:100177. [PMID: 35143845 PMCID: PMC8953687 DOI: 10.1016/j.jlr.2022.100177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 12/02/2022] Open
Abstract
Desulfation of cholesterol sulfate (CholS) to cholesterol (Chol) is an important event in epidermal homeostasis and necessary for stratum corneum (SC) barrier function. The CholS/Chol ratio decreases during SC maturation but remains high in pathological conditions, such as X-linked ichthyosis, characterized by dry and scaly skin. The aim of this study was to characterize the influence of the CholS/Chol molar ratio on the structure, dynamics, and permeability of SC lipid model mixtures. We synthesized deuterated CholS and investigated lipid models with specifically deuterated components using 2H solid-state NMR spectroscopy at temperatures from 25°C to 80°C. Although the rigid acyl chains in ceramides and fatty acids remained essentially rigid upon variation of the CholS/Chol ratio, both sterols were increasingly fluidized in lipid models containing higher CholS concentrations. We also show the X-ray repeat distance of the lipid lamellar phase (105 Å) and the orthorhombic chain packing of the ceramide’s acyl chains and long free fatty acids did not change upon the variation of the CholS content. However, the Chol phase separation visible in models with high Chol concentration disappeared at the 50:50 CholS/Chol ratio. This increased fluidity resulted in higher permeabilities to model markers of these SC models. These results reveal that a high CholS/Chol ratio fluidizes the sterol fraction and increases the permeability of the SC lipid phase while maintaining the lamellar lipid arrangement with an asymmetric sterol distribution.
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14
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Ni J, Liu Y, Hong H, Kong X, Han Y, Zhang L, Zhang Y, Zhang Y, Hua C, Wang Q, Wang X, Huang Y, YiKun W, Meili D. A novel fluorescent digitonin derivative for non-invasive skin cholesterol detection: potential application in atherosclerosis screening. RSC Adv 2022; 12:18397-18406. [PMID: 35799936 PMCID: PMC9214714 DOI: 10.1039/d2ra01982e] [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: 03/28/2022] [Accepted: 05/27/2022] [Indexed: 12/03/2022] Open
Abstract
There is a great demand for the rapid and non-invasive atherosclerosis screening method. Cholesterol content in the epidermis of the skin is an early biomarker for atherosclerosis. Risk assessment of atherosclerosis can be achieved by measuring cholesterol in the epidermis. Here, we synthesised a new fluorescent digitonin derivative (FDD) for the non-invasive detection of skin cholesterol. The results of fluorescence spectroscopy studies indicated that the probe exhibited desirable selectivity for cholesterol. The proof-of-concept preclinical study confirmed that FDD can detect different concentrations of skin cholesterol; patients diagnosed with atherosclerotic cardiovascular disease and the at-risk atherosclerosis group exhibited higher skin cholesterol content than the normal group. The area under the ROC curve for distinguishing the normal/disease group was 0.9228 (95% confidence interval, 0.8938 to 0.9518), and the area under the ROC curve for distinguishing the normal/risk group was 0.9422 (95% confidence interval, 0.9178 to 0.9665). We anticipate that this non-invasive skin cholesterol test may be used as a risk assessment tool for atherosclerosis screening in a large population for further examination and intervention in high-risk populations. Digitonin was used to synthesise a fluorescence probe for the non-invasive detection of skin cholesterol. This non-invasive skin cholesterol method may be used as a risk assessment tool for atherosclerosis screening in a large population.![]()
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Affiliation(s)
- Jingshu Ni
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
| | - Yong Liu
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Haiou Hong
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Xiangyong Kong
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Yongsheng Han
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Lei Zhang
- Anhui Provincial Institute for Food and Drug Control, Hefei, 230051, China
| | - Yang Zhang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
| | - Yuanzhi Zhang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Changyi Hua
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Quanfu Wang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Xia Wang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Yao Huang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Wang YiKun
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Dong Meili
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Provincial Engineering Laboratory for Medical Optical Diagnosis &Treatment Technology and Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
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15
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Fujii M. The Pathogenic and Therapeutic Implications of Ceramide Abnormalities in Atopic Dermatitis. Cells 2021; 10:2386. [PMID: 34572035 PMCID: PMC8468445 DOI: 10.3390/cells10092386] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/05/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
Ceramides play an essential role in forming a permeability barrier in the skin. Atopic dermatitis (AD) is a common chronic skin disease associated with skin barrier dysfunction and immunological abnormalities. In patients with AD, the amount and composition of ceramides in the stratum corneum are altered. This suggests that ceramide abnormalities are involved in the pathogenesis of AD. The mechanism underlying lipid abnormalities in AD has not yet been fully elucidated, but the involvement of Th2 and Th1 cytokines is implicated. Ceramide-dominant emollients have beneficial effects on skin barrier function; thus, they have been approved as an adjunctive barrier repair agent for AD. This review summarizes the current understanding of the mechanisms of ceramide abnormalities in AD. Furthermore, the potential therapeutic approaches for correcting ceramide abnormalities in AD are discussed.
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Affiliation(s)
- Masanori Fujii
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
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16
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Petracca B, Nădăban A, Eeman M, Gooris GS, Bouwstra JA. Effects of ozone on stratum corneum lipid integrity and assembly. Chem Phys Lipids 2021; 240:105121. [PMID: 34352254 DOI: 10.1016/j.chemphyslip.2021.105121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/04/2021] [Accepted: 07/30/2021] [Indexed: 10/20/2022]
Abstract
The stratum corneum (SC) acts as the main barrier of the skin against exogenous substances (e.g. air pollutants) and against the loss of endogenous substances such as water. The SC consists of keratin-rich dead cells surrounded by crystalline lamellar lipid regions. The main lipid classes are ceramides (CERs), free fatty acids (FFAs), and cholesterol (CHOL). Tropospheric ozone (O3) is a potent oxidant compound that reacts instantly with biological molecules such as lipids and proteins. Although it has been reported that O3 induces biological responses at the cellular level, to the best of our knowledge, there is no information related to the damages O3 can cause at the level of the SC extracellular lipid matrix. The aim of our work was to investigate which SC lipid subclasses are prone to oxidation when exposed to O3 and how the changes in chemical structures affect the lipid organization in a stratum corneum substitute (SCS) membrane. Ultimately the barrier properties of the SCS were examined. Our studies reveal that O3 induces chemical modifications of the unsaturated bonds in CERs and CHOL. The appearance of carbonyl groups at the headgroup level and the removal of the linoleate moiety of omega acylceramides (CER EOS) impact the lamellar organization of the lipid assembly and to a lesser extent the lateral packing of the lipids. Unexpectedly, the modifications improved the barrier function of the SCS.
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Affiliation(s)
- Benedetta Petracca
- Dow Silicones Belgium SRL, Rue Jules Bordet, Parc Industriel Zone C, B-7180 Seneffe, Belgium; Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Andreea Nădăban
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, the Netherlands
| | - Marc Eeman
- Dow Silicones Belgium SRL, Rue Jules Bordet, Parc Industriel Zone C, B-7180 Seneffe, Belgium.
| | - Gert S Gooris
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, the Netherlands
| | - Joke A Bouwstra
- Division of Biotherapeutics, Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, the Netherlands
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17
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Ni J, Hong H, Zhang Y, Tang S, Han Y, Fang Z, Zhang Y, Zhou N, Wang Q, Liu Y, Li Z, Wang Y, Dong M. Development of a non-invasive method for skin cholesterol detection: pre-clinical assessment in atherosclerosis screening. Biomed Eng Online 2021; 20:52. [PMID: 34074299 PMCID: PMC8170999 DOI: 10.1186/s12938-021-00889-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 05/18/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Establishing a high-accuracy and non-invasive method is essential for evaluating cardiovascular disease. Skin cholesterol is a novel marker for assessing the risk of atherosclerosis and can be used as an independent risk factor of early assessment of atherosclerotic risk. METHODS We propose a non-invasive skin cholesterol detection method based on absorption spectroscopy. Detection reagents specifically bind to skin cholesterol and react with indicator to produce colored products, the skin cholesterol content can be obtained through absorption spectrum information on colored products detected by non-invasive technology. Gas chromatography is used to measure cholesterol extracted from the skin to verify the accuracy and reliability of the non-invasive test method. A total of 342 subjects were divided into normal group (n = 115), disease group (n = 110) and risk group (n = 117). All subjects underwent non-invasive skin cholesterol test. The diagnostic accuracy of the measured value was analyzed by receiver-operating characteristic (ROC) curve. RESULTS The proposed method is able to identify porcine skin containing gradient concentration of cholesterol. The values measured by non-invasive detection method were significantly correlated with gas chromatography measured results (r = 0.9074, n = 73, p < 0.001). Bland-Altman bias was - 72.78 ± 20.03 with 95% limits of agreement - 112.05 to - 33.51, falling within the prespecified clinically non-significant range. We further evaluated the method of patients with atherosclerosis and risk population as well as normal group, patients and risk atherosclerosis group exhibited higher skin cholesterol content than normal group (all P < 0.001). The area under the ROC curve for distinguishing Normal/Disease group was 0.8642 (95% confidence interval, 0.8138 to 0.9146), meanwhile, the area under the ROC curve for distinguishing Normal/Risk group was 0.8534 (95% confidence interval, 0.8034 to 0.9034). CONCLUSIONS The method demonstrated its capability of detecting different concentration of skin cholesterol. This non-invasive skin cholesterol detection system may potentially be used as a risk assessment tool for atherosclerosis screening, especially for a large population.
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Affiliation(s)
- Jingshu Ni
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
| | - Haiou Hong
- Health Management Center, First Affiliated Hospital of University of Science and Technology of China, Hefei, China
| | - Yang Zhang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
| | - Shiqi Tang
- Health Management Center, Renmin Hospital of WuHan University, Wuhan, 430060, China
| | - Yongsheng Han
- Department of Cardiovascular Medicine, First Affiliated Hospital of University of Science and Technology of China, Hefei, 230001, China
| | - Zhaohui Fang
- Department of Endocrinology, The First Affiliated Hospital of Anhui University of Traditional Chinese Medicine, Hefei, 230031, China
| | - Yuanzhi Zhang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Nan Zhou
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Quanfu Wang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Yong Liu
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
- Wanjiang Center for Development of Emerging Industrial Technology, Tongling, 244000, China
| | - Zhongsheng Li
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China
| | - YiKun Wang
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China.
- University of Science and Technology of China, Hefei, 230026, China.
| | - Meili Dong
- Anhui Provincial Engineering Technology Research Center for Biomedical Optical Instrument, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science , Chinese Academy of Sciences, Hefei, 230031, China.
- University of Science and Technology of China, Hefei, 230026, China.
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18
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Schmitt T, Neubert RHH. State of the Art in Stratum Corneum Research. Part II: Hypothetical Stratum Corneum Lipid Matrix Models. Skin Pharmacol Physiol 2020; 33:213-230. [PMID: 32683377 DOI: 10.1159/000509019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/05/2020] [Indexed: 12/31/2022]
Abstract
This review is the second part of a series which presents the state of the art in stratum corneum (SC) lipid matrix (LM) research in depth. In this part, the various hypothetical models which were developed to describe the structure and function of the SC LM as the skin's barrier will be discussed. New as well as a cumulative assortment of older results which change the view on the different models are considered to conclude how well the different models are holding up today. As a final conclusion, a model, factoring in as much of the known data as possible, is concluded, unifying the varying different models into one which can be developed further, as new results are found in the future. So far, the model is described with a single crystalline or gel-like phase with a certain amount of nanocrystallites of concentrated ceramides (CERs) and free fatty acids and more fluid nanodomains caused by a fluidizing effect of the cholesterol. These domains are dynamically resolved and reformed and do not impair the barrier function. The chain conformation is not completely clear yet; however, an equilibrium of fully extended and hairpin-folded CERs with ratios depending on the properties of each individual CER species is proposed as most likely. An overlapping middle layer as described for the tri-layer model in part I of this series would be present for both conformations. The macroscopic broad-narrow-broad layering, observed in electron micrographs, is explained by an external templating by the lipid envelope, and an internal templating by short and long lipid chains each preferentially show a homophilic association, forming thicker and thinner bilayers, respectively. The degree of influence of the very long ω-hydroxy-CERs is discussed as well.
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Affiliation(s)
- Thomas Schmitt
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Reinhard H H Neubert
- Institute of Applied Dermatopharmacy at the Martin Luther University Halle-Wittenberg (IADP), Halle/Saale, Germany, .,Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany,
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19
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Badhe Y, Gupta R, Rai B. Development and application of coarse-grained MARTINI model of skin lipid ceramide [AP]. J Mol Model 2020; 26:182. [PMID: 32583227 DOI: 10.1007/s00894-020-04435-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 06/02/2020] [Indexed: 01/10/2023]
Abstract
Stratum corneum (SC), the outermost layer of the skin, contains large variety of lipids, endowing them with the amphiphilic properties, needed to fulfil their key role in skin's barrier function. The individual role of lipid types in the barrier function is difficult to understand due to the immense heterogeneity and complexity of the lipid's organization within the SC. The lipid organization is being explored using both computational (molecular dynamics simulations) and experimental (neutron diffraction) techniques. Even though atomistic simulations provide unprecedented atomic level details, the major limitation is time and length scale that can be achieved with decent computational facility. Alternatively, coarse-grain (CG) models are currently being used to capture physics at bigger time and length scale without losing essential underlined structural information. In this study, a CG model of α-hydroxy phytosphingosines (CER[AP]) is developed based on philosophy of MARTINI force field. At first, the model is validated with various atomistic simulations and available experimental data. Later on, the model's compatibility with other major skin lipids, cholesterol, and free fatty acid (palmitic acid) is checked by simulating a mixture of lipid multilayer in presence and absence of water. The developed model of CER[AP] is able to predict key structural properties within the acceptable error limits. The phenomena of ceramide conformation transformation, cholesterol flip-flop, and specificity of lipid arrangement within the multilayered systems is observed during the simulation. This signifies the importance of model in capturing higher order structural transformations.
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Affiliation(s)
- Yogesh Badhe
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India
| | - Rakesh Gupta
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India.
| | - Beena Rai
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India
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20
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Kováčik A, Pullmannová P, Pavlíková L, Maixner J, Vávrová K. Behavior of 1-Deoxy-, 3-Deoxy- and N-Methyl-Ceramides in Skin Barrier Lipid Models. Sci Rep 2020; 10:3832. [PMID: 32123227 PMCID: PMC7051948 DOI: 10.1038/s41598-020-60754-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/13/2020] [Indexed: 11/21/2022] Open
Abstract
Ceramides (Cer) are essential components of the skin permeability barrier. To probe the role of Cer polar head groups involved in the interfacial hydrogen bonding, the N-lignoceroyl sphingosine polar head was modified by removing the hydroxyls in C-1 (1-deoxy-Cer) or C-3 positions (3-deoxy-Cer) and by N-methylation of amide group (N-Me-Cer). Multilamellar skin lipid models were prepared as equimolar mixtures of Cer, lignoceric acid and cholesterol, with 5 wt% cholesteryl sulfate. In the 1-deoxy-Cer-based models, the lipid species were separated into highly ordered domains (as found by X-ray diffraction and infrared spectroscopy) resulting in similar water loss but 4–5-fold higher permeability to model substances compared to control with natural Cer. In contrast, 3-deoxy-Cer did not change lipid chain order but promoted the formation of a well-organized structure with a 10.8 nm repeat period. Yet both lipid models comprising deoxy-Cer had similar permeabilities to all markers. N-Methylation of Cer decreased lipid chain order, led to phase separation, and improved cholesterol miscibility in the lipid membranes, resulting in 3-fold increased water loss and 10-fold increased permeability to model compounds compared to control. Thus, the C-1 and C-3 hydroxyls and amide group, which are common to all Cer subclasses, considerably affect lipid miscibility and chain order, formation of periodical nanostructures, and permeability of the skin barrier lipid models.
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Affiliation(s)
- Andrej Kováčik
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005, Hradec Králové, Czech Republic
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005, Hradec Králové, Czech Republic
| | - Ludmila Pavlíková
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005, Hradec Králové, Czech Republic
| | - Jaroslav Maixner
- University of Chemistry and Technology in Prague, Faculty of Chemical Technology, Technická 5, 166 28, Prague, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 50005, Hradec Králové, Czech Republic.
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21
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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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22
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Wenzel T, Carvajal Berrio DA, Daum R, Reisenauer C, Weltmann KD, Wallwiener D, Brucker SY, Schenke-Layland K, Brauchle EM, Weiss M. Molecular Effects and Tissue Penetration Depth of Physical Plasma in Human Mucosa Analyzed by Contact- and Marker-Independent Raman Microspectroscopy. ACS APPLIED MATERIALS & INTERFACES 2019; 11:42885-42895. [PMID: 31657892 DOI: 10.1021/acsami.9b13221] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Noninvasive epithelial tissue treatment with cold atmospheric plasma (CAP) is a promising option for local treatment of chronic inflammatory and precancerous lesions as well as various mucosal cancer diseases. Atmospheric pressure plasma jets (APPJ) are well-characterized and medically approved plasma sources. There are numbers of medically approved plasma sources for the treatment of epithelial diseases; however, little is known about the biochemical effects of CAP at the plasma-tissue interface. Furthermore, the actual penetration depth of CAP into tissue is currently unclear. Noninvasive and marker-independent Raman microspectroscopy was employed to assess the molecular effects of CAP on single cells and primary human cervical tissue samples. CAP treatment showed immediate and persisting changes of specific molecular tissue components determined by multivariate analysis. Raman imaging identified CAP-dependent changes in the morphology of the tissue, as well as molecular tissue components. The expression of the different components was not significantly altered within 24 h of incubation. DNA and lipids showed the strongest changes upon CAP treatment, which were traced to the basal cell layer of cervical epithelium, corresponding to an average functional plasma penetration depth of roughly 270 μm. In this study, Raman microspectroscopy is shown to be a promising method for molecular single-cell and solid tissue characterization. Regarding CAP treatment of tissues, Raman microspectroscopy could be suitable for the screening of biological mechanisms as well as for future contact- and marker-independent monitoring of plasma tissue effects.
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Affiliation(s)
- Thomas Wenzel
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
| | | | - Ruben Daum
- Natural and Medical Sciences Institute (NMI) , Reutlingen , Germany
| | - Christl Reisenauer
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
| | | | - Diethelm Wallwiener
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
| | - Sara Y Brucker
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
| | - Katja Schenke-Layland
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
- Natural and Medical Sciences Institute (NMI) , Reutlingen , Germany
- Department of Medicine/Cardiology , University of California Los Angeles (UCLA) , Los Angeles , United States
| | - Eva-Maria Brauchle
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
- Natural and Medical Sciences Institute (NMI) , Reutlingen , Germany
| | - Martin Weiss
- Department of Women's Health Tübingen , Calwerstraße 7 , 72076 Tübingen , Germany
- Natural and Medical Sciences Institute (NMI) , Reutlingen , Germany
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23
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Čuříková-Kindlová BA, Diat O, Štěpánek F, Vávrová K, Zbytovská J. Probing the interactions among sphingosine and phytosphingosine ceramides with non- and alpha-hydroxylated acyl chains in skin lipid model membranes. Int J Pharm 2019; 563:384-394. [PMID: 30959237 DOI: 10.1016/j.ijpharm.2019.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 11/26/2022]
Abstract
Ceramides (Cers) are significant constituents of the stratum corneum (SC), the uppermost skin layer responsible for skin barrier properties. Cers are a heterogeneous group of lipids whose mutual interactions are still unclear. To better understand these interactions, we characterized model membranes containing stearic acid, cholesterol, cholesterol sulfate and one or more of the following ceramides: N-stearoyl-sphingosine (CerNS), N-stearoyl-phytosphingosine (CerNP) and N-(2-hydroxy)stearoyl-phytosphingosine (CerAP). Small angle X-ray scattering and FTIR spectroscopy were used to study lipid arrangement, phase separation and thermotropic behaviour. In the one-Cer systems, the membranes with CerNP showed strong hydrogen bonding and significant phase separation, even after phase transition, while the systems containing CerAP and CerNS had increased lipid miscibility. The multi-Cer systems exhibited different behaviour. In particular, the membrane containing all three Cers was a highly miscible system with narrow one-step phase transition, which, of all the studied samples, occurred at the lowest temperatures. Our results show that even a small variation in Cer structure results in substantially different phase behaviour, which is further affected by the presence of other Cer subclasses. Interestingly, the phase behaviour of the most complex three-Cer system was simpler than that of the others, highlighting the importance of lipid diversity in real SC.
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Affiliation(s)
- Barbora Amélie Čuříková-Kindlová
- University of Chemistry and Technology Prague, Faculty of Chemical Technology, Department of Organic Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Olivier Diat
- Institute de Chimie Séparative de Marcoule, ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Bagnols-sur-Cèze, France
| | - František Štěpánek
- University of Chemistry and Technology Prague, Faculty of Chemical Engineering, Department of Chemical Engineering, Technická 5, 166 28 Prague, Czech Republic
| | - Kateřina Vávrová
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Jarmila Zbytovská
- University of Chemistry and Technology Prague, Faculty of Chemical Technology, Department of Organic Technology, Technická 5, 166 28 Prague, Czech Republic; Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
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24
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Pullmannová P, Ermakova E, Kováčik A, Opálka L, Maixner J, Zbytovská J, Kučerka N, Vávrová K. Long and very long lamellar phases in model stratum corneum lipid membranes. J Lipid Res 2019; 60:963-971. [PMID: 30885924 PMCID: PMC6495169 DOI: 10.1194/jlr.m090977] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/25/2019] [Indexed: 11/20/2022] Open
Abstract
Membrane models of the stratum corneum (SC) lipid barrier, either healthy or affected by recessive X-linked ichthyosis, constructed from ceramide [Cer; nonhydroxyacyl sphingosine N-tetracosanoyl-d-erythro-sphingosine (CerNS24) alone or with omega-O-acylceramide N-(32-linoleyloxy)dotriacontanoyl-d-erythro-sphingosine (CerEOS)], FFAs(C16-24), cholesterol (Chol), and sodium cholesteryl sulfate (CholS) were investigated. X-ray diffraction (XRD) revealed a previously unreported polymorphism of the membranes. In the absence of CerEOS, the membranes formed a short lamellar phase (SLP; the repeat distance d = 5.3 nm), a medium lamellar phase (MLP; d = 10.6 nm), or very long lamellar phases (VLLP; d = 15.9 and 21.2 nm). An increased CholS-to-Chol ratio modulated the membrane polymorphism, although the CholS phase separated at ≥ 7 weight% (of total lipids). The presence of CerEOS led to the stable long lamellar phase (LLP) with d = 12.2 nm and prevented VLLP formation. Our XRD results agree well with recently published cryo-electron microscopy data for vitreous skin sections, while also revealing new structures. Thus, lamellar phases with long repeat distances (MLP and VLLP) may be formed in the absence of omega-O-acylceramide, whereas these ultralong Cer species likely stabilize the final SC lipid architecture of LLP by riveting the adjacent lipid layers.
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Affiliation(s)
- Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic.
| | - Elena Ermakova
- Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - Andrej Kováčik
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic
| | - Lukáš Opálka
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic
| | - Jaroslav Maixner
- University of Chemistry and Technology Prague 166 28 Prague, Czech Republic
| | - Jarmila Zbytovská
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic; University of Chemistry and Technology Prague 166 28 Prague, Czech Republic
| | - Norbert Kučerka
- Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research, Dubna 141980, Russia; Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, 832 32 Bratislava, Slovak Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic
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