Electron paramagnetic resonance (EPR) spectroscopy represents an established tool to study properties of microenvironments, e.g. to investigate the structure and dynamics of biological and artificial membranes. In this study, the partitioning of the spin probe 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in ex vivo human abdominal and breast skin, ex vivo porcine abdominal and ear skin as well as normal and inflammatory in vitro skin equivalents was investigated by EPR spectroscopy. Furthermore, the stratum corneum (SC) lipid composition (as determined by high-performance thin-layer chromatography), SC lipid chain order (probed by infrared spectroscopy) and the SC thickness (investigated by histology) were determined in the skin models. X-band EPR measurements have shown that TEMPO partitions in the lipophilic and hydrophilic microenvironment in varying ratios in different ex vivo and in vitro skin models. Ex vivo human abdominal skin exhibited the highest amount of TEMPO in the lipophilic microenvironment. In contrast, the lowest amount of TEMPO in the lipophilic microenvironment was determined in ex vivo human breast skin and the inflammatory in vitro skin equivalents. Individual EPR spectra of epidermis including SC and dermis indicated that the lipophilic microenvironment of TEMPO mainly corresponds to the most lipophilic part of the epidermis, the SC. The amount of TEMPO in the lipophilic microenvironment was independent of the SC lipid composition and the SC lipid chain order but correlated with the SC thickness. In conclusion, EPR spectroscopy could be a novel technique to determine differences in the SC thickness, thus suitably complementing existing methods.
- MeSH
- břicho MeSH
- buněčné mikroprostředí MeSH
- chromatografie na tenké vrstvě MeSH
- cyklické N-oxidy chemie MeSH
- dospělí MeSH
- elektronová paramagnetická rezonance MeSH
- epidermis chemie MeSH
- kůže chemie cytologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- lipidy chemie MeSH
- mladý dospělý MeSH
- prasata MeSH
- prsy MeSH
- senioři MeSH
- spektrofotometrie infračervená MeSH
- spinové značení MeSH
- tloušťka kožní řasy MeSH
- zevní ucho MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Dermal fibroblasts seem critical for epidermal maturation and differentiation and recent work demonstrated that diseased fibroblasts may drive pathophysiological processes. Nevertheless, still very little is known about the actual crosstalk between epidermal keratinocytes and dermal fibroblasts and the impact of dermal fibroblasts on epidermal maturation and differentiation. Aiming for a more fundamental understanding of the impact of the cellular crosstalk between keratinocytes and fibroblasts on the skin homeostasis, we generated full-thickness skin equivalents with and without fibroblasts and subsequently analysed them for the expression of skin differentiation markers, their barrier function, skin lipid content and epidermal cell signalling. Skin equivalents without fibroblasts consistently showed an impaired differentiation and dysregulated expression of skin barrier and tight junction proteins, increased skin permeability, and a decreased skin lipid/protein ratio. Most interestingly, impaired Ras/Raf/ERK/MEK signalling was evident in skin equivalents without fibroblasts. Our data clearly indicate that the epidermal-dermal crosstalk between keratinocytes and fibroblasts is critical for adequate skin differentiation and that fibroblasts orchestrate epidermal differentiation processes.
- MeSH
- buněčná diferenciace MeSH
- epidermální buňky metabolismus patologie MeSH
- epidermis metabolismus MeSH
- fibroblasty metabolismus MeSH
- homeostáza genetika fyziologie MeSH
- keratinocyty metabolismus patologie MeSH
- kožní absorpce MeSH
- kůže metabolismus patologie MeSH
- lidé MeSH
- permeabilita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mutations in the gene encoding for filaggrin (FLG) are major predisposing factors for atopic dermatitis (AD). Besides genetic predisposition, immunological dysregulations considerably contribute to its pathophysiology. For example, thymic stromal lymphopoietin (TSLP) is highly expressed in lesional atopic skin and significantly contributes to the pathogenesis of AD by activating dendritic cells that then initiate downstream effects on, for example, T cells. However, little is known about the direct interplay between TSLP, filaggrin-deficient skin and other immune cells such as T lymphocytes. In the present study, FLG knockdown skin equivalents, characterised by intrinsically high TSLP levels, were exposed to activated CD4+ T cells. T cell exposure resulted in an inflammatory phenotype of the skin equivalents. Furthermore, a distinct shift from a Th1/Th17 to a Th2/Th22 profile was observed following exposure of T cells to filaggrin-deficient skin equivalents. Interestingly, TSLP directly stimulated T cell migration exclusively in filaggrin-deficient skin equivalents even in the absence of dendritic cells, indicating a hitherto unknown role of TSLP in the pathogenesis of AD.
- MeSH
- aktivace lymfocytů MeSH
- buňky Th17 imunologie metabolismus MeSH
- CD4-pozitivní T-lymfocyty imunologie metabolismus MeSH
- cytokiny metabolismus MeSH
- dendritické buňky imunologie metabolismus MeSH
- exprese genu MeSH
- kůže imunologie metabolismus MeSH
- lidé MeSH
- metabolismus lipidů MeSH
- pohyb buněk imunologie MeSH
- proteiny intermediálních filament nedostatek MeSH
- proteiny těsného spoje genetika metabolismus MeSH
- T-lymfocyty - podskupiny imunologie metabolismus MeSH
- Th1 buňky imunologie metabolismus MeSH
- Th2 buňky imunologie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Therapeutic options for atopic dermatitis mostly address the symptoms but causal therapies are still missing. Peroxisome proliferator activated receptor (PPAR) agonists exert beneficial effects in patients suffering this disease, whereas the stimulation of PPARα and γ seemed most promising. OBJECTIVES: To elucidate the effects of the PPARα specific agonist WY14643, the PPARγ agonist ciglitazone, and the dual PPARα+γ agonist docosahexaenoic acid (DHA) on the homeostasis and barrier function of filaggrin deficient skin. METHODS: The effects of the PPAR agonists on skin differentiation were evaluated via qPCR, Western blot, histological or immunofluorescence staining. Skin lipid organization was determined by ATR-FTIR and lipid composition was analyzed by HPTLC. Ultimately, the skin barrier function was assessed by skin absorption studies using the radioactively labeled compound testosterone. RESULTS: Significant upregulation of filaggrin after DHA and WY14643 supplementation, but no effect of ciglitazone, on protein and mRNA level was detected. DHA and WY14643, but not ciglitazone, normalized the molar ratio of the main skin barrier lipids to 1:1:1 (free fatty acids:ceramides:cholesterol). Furthermore, DHA and WY14643 supplementation normalized the skin lipid profile in filaggrin deficient skin, but only WY14643 significantly improved the skin barrier function. CONCLUSION: Supplementation particularly with the PPARα agonist WY14643 improved the homeostasis and barrier function of filaggrin deficient skin models by normalization of the free fatty acid profile underlining the potential of PPAR agonists for the treatment of filaggrin-associated skin diseases.
- MeSH
- časové faktory MeSH
- fenotyp MeSH
- fibroblasty účinky léků metabolismus MeSH
- genotyp MeSH
- kožní absorpce účinky léků MeSH
- kultivované buňky MeSH
- kůže účinky léků metabolismus MeSH
- kyseliny dokosahexaenové farmakologie MeSH
- kyseliny mastné neesterifikované metabolismus MeSH
- lidé MeSH
- membránové proteiny genetika metabolismus MeSH
- metabolismus lipidů účinky léků MeSH
- permeabilita MeSH
- PPAR alfa agonisté metabolismus MeSH
- PPAR gama agonisté metabolismus MeSH
- proteinové prekurzory genetika metabolismus MeSH
- proteiny intermediálních filament nedostatek genetika MeSH
- pyrimidiny farmakologie MeSH
- RNA interference MeSH
- signální transdukce účinky léků MeSH
- testosteron metabolismus MeSH
- thiazolidindiony farmakologie MeSH
- transfekce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hyaluronic acid (HA) hydrogels are interesting delivery systems for topical applications. Besides moisturizing the skin and improving wound healing, HA facilitates topical drug absorption and is highly compatible with labile biomacromolecules. Hence, in this study we investigated the influence of HA hydrogels with different molecular weights (5 kDa, 100 kDa, 1 MDa) on the skin absorption of the model protein bovine serum albumin (BSA) using fluorescence lifetime imaging microscopy (FLIM). To elucidate the interactions of HA with the stratum corneum and the skin absorption of HA itself, we combined FLIM and Fourier-transform infrared (FTIR) spectroscopy. Our results revealed distinct formulation and skin-dependent effects. In barrier deficient (tape-stripped) skin, BSA alone penetrated into dermal layers. When BSA and HA were applied together, however, penetration was restricted to the epidermis. In normal skin, penetration enhancement of BSA into the epidermis was observed when applying low molecular weight HA (5 kDa). Fluorescence resonance energy transfer analysis indicated close interactions between HA and BSA under these conditions. FTIR spectroscopic analysis of HA interactions with stratum corneum constituents showed an α-helix to β-sheet interconversion of keratin in the stratum corneum, increased skin hydration, and intense interactions between 100 kDa HA and the skin lipids resulting in a more disordered arrangement of the latter. In conclusion, HA hydrogels restricted the delivery of biomacromolecules to the stratum corneum and viable epidermis in barrier deficient skin, and therefore seem to be potential topical drug vehicles. In contrast, HA acted as an enhancer for delivery in normal skin, probably mediated by a combination of cotransport, increased skin hydration, and modifications of the stratum corneum properties.
- MeSH
- aplikace kožní MeSH
- kožní absorpce MeSH
- kůže metabolismus MeSH
- kyselina hyaluronová chemie MeSH
- prasata MeSH
- sérový albumin hovězí chemie metabolismus MeSH
- skot MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- techniky in vitro MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
