The activity of the light-oxygen-voltage/helix-turn-helix (LOV-HTH) photoreceptor EL222 is regulated through protein-protein and protein-DNA interactions, both triggered by photo-excitation of its flavin mononucleotide (FMN) cofactor. To gain molecular-level insight into the photocycle of EL222, we applied complementary methods: macromolecular X-ray crystallography (MX), nuclear magnetic resonance (NMR) spectroscopy, optical spectroscopies (infrared and UV-visible), molecular dynamics/metadynamics (MD/metaD) simulations, and protein engineering using noncanonical amino acids. Kinetic experiments provided evidence for two distinct EL222 conformations (lit1 and lit2) that become sequentially populated under illumination. These two lit states were assigned to covalently bound N5 protonated, and noncovalently bound hydroquinone forms of FMN, respectively. Only subtle structural differences were observed between the monomeric forms of all three EL222 species (dark, lit1, and lit2). While the dark state is largely monomeric, both lit states undergo monomer-dimer exchange. Furthermore, molecular modeling revealed differential dynamics and interdomain separation times arising from the three FMN states (oxidized, adduct, and reduced). Unexpectedly, all three EL222 species can associate with DNA, but only upon blue-light irradiation, a high population of stable complexes is obtained. Overall, we propose a model of EL222 activation where photoinduced changes in the FMN moiety shift the population equilibrium toward an open conformation that favors self-association and DNA-binding.
- MeSH
- Bacterial Proteins chemistry metabolism MeSH
- DNA-Binding Proteins chemistry metabolism MeSH
- DNA * chemistry metabolism MeSH
- Flavin Mononucleotide * chemistry metabolism MeSH
- Flavins chemistry metabolism MeSH
- Kinetics MeSH
- Protein Conformation MeSH
- Crystallography, X-Ray MeSH
- Oxidation-Reduction * MeSH
- Molecular Dynamics Simulation MeSH
- Light * MeSH
- Thermosynechococcus metabolism MeSH
- Transcription Factors metabolism chemistry MeSH
- Protein Binding MeSH
- Publication type
- Journal Article MeSH
Skin represents the largest organ in the human body, functioning as a protective barrier against environmental factors while playing a critical role in thermoregulation. Acne vulgaris is recognized as the most common dermatological condition affecting adolescents, and if left untreated, it can result in lasting skin damage and associated psychosocial challenges. This study aims to develop innovative polymeric biomaterials that could effectively support the treatment of acne vulgaris. The synthesis of these biomaterials involves the use of polyethylene glycol 6000, sodium alginate, and the antioxidant protein glutathione (GHS) to create polymeric hydrogels. These hydrogels were generated via a UV-mediated crosslinking process. To enhance the functional properties of the hydrogels, zinc oxide microparticles (ZnO), synthesized through a wet precipitation method, were incorporated into the formulations. Characterization of the ZnO was performed using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), particle sizer analysis, and Scanning Electron Microscopy (SEM). Additionally, the bioactivity of the synthesized materials was evaluated through incubation in media simulating physiological body fluids. The cytotoxic effects of the biomaterials were assessed using an indirect test on mouse fibroblast (L929) cells, in accordance with ISO 10993-5 guidelines. The results of our research indicate that the developed biomaterials exhibit potential as a carrier for active substances, contributing positively to the treatment of acne vulgaris and potentially improving overall skin health.
- MeSH
- Acne Vulgaris drug therapy MeSH
- Alginates chemistry MeSH
- Biocompatible Materials chemistry pharmacology MeSH
- Cell Line MeSH
- Fibroblasts drug effects metabolism MeSH
- Glutathione * metabolism MeSH
- Hydrogels * chemistry MeSH
- Skin * drug effects metabolism MeSH
- Humans MeSH
- Mice MeSH
- Drug Carriers chemistry MeSH
- Zinc Oxide * chemistry pharmacology MeSH
- Regeneration drug effects MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
This study summarizes the response of cyanobacterium Spirulina subsalsa HKAR-19 under simulated light conditions of photosynthetically active radiation (PAR), PAR+UV-A (PA), and PAR+UV-A+UV-B (PAB). Exposure to UV radiation caused a significant (P < 0.05) decrease in chlorophyll a, phycocyanin, and total protein. In contrast, total carotene content increased significantly (P < 0.05) under PA and PAB with increasing irradiation time. The photosynthetic efficiency of photosystem II also decreased significantly in PA and PAB radiation. We have also recorded a decrease in the fluorescence emission intensity of phycocyanin under PA and PAB exposure. The phycocyanin fluorescence shifted towards shorter wavelengths (blue-shift) after 72 h of PA and PAB exposure. Intracellular reactive oxygen species (ROS) levels increased significantly in PA and PAB. Fluorescence microscopic images showed an increase in green fluorescence, indicating ROS generation in UV radiation. We have also quantified ROS generation using green and red fluorescence ratio represented as G/R ratio. A 2-6-fold increase in antioxidative enzymes activity was observed to overcome the damaging effects caused by UV stress as compared to untreated control cultures. The lipid peroxidation was assessed in terms of malondialdehyde content which increases significantly (P < 0.05) as the duration of exposure increases. These results suggest that a combined effect of PAR, UV-A, and UV-B was more deleterious than an individual one.
- MeSH
- Antioxidants * metabolism MeSH
- Chlorophyll A metabolism MeSH
- Chlorophyll * metabolism MeSH
- Photosynthesis * radiation effects MeSH
- Photosystem II Protein Complex metabolism MeSH
- Phycocyanin * metabolism MeSH
- Carotenoids metabolism MeSH
- Lipid Peroxidation radiation effects MeSH
- Reactive Oxygen Species * metabolism MeSH
- Spirulina * radiation effects metabolism MeSH
- Ultraviolet Rays * MeSH
- Publication type
- Journal Article MeSH
Restoring the structures and functions of tissues along with organs in human bodies is a topic gathering attention nowadays. These issues are widely discussed in the context of regenerative medicine. Excipients/delivery systems play a key role in this topic, guaranteeing a positive impact on the effectiveness of the drugs or therapeutic substances supplied. Advances in materials engineering, particularly in the development of hydrogel biomaterials, have influenced the idea of creating an innovative material that could serve as a carrier for active substances while ensuring biocompatibility and meeting all the stringent requirements imposed on medical materials. This work presents the preparation of a natural polymeric material based on pullulan modified with silymarin, which belongs to the group of flavonoids and derives from a plant called Silybum marianum. Under UV light, matrices with a previously prepared composition were crosslinked. Before proceeding to the next stage of the research, the purity of the composition of the matrices was checked using Fourier-transform infrared (FT-IR) spectroscopy. Incubation tests lasting 19 days were carried out using incubation fluids such as simulated body fluid (SBF), Ringer's solution, and artificial saliva. Changes in pH, electrolytic conductivity, and weight were observed and then used to determine the sorption capacity. During incubation, SBF proved to be the most stable fluid, with a pH level of 7.6-7.8. Sorption tests showed a high sorption capacity of samples incubated in both Ringer's solution and artificial saliva (approximately 350%) and SBF (approximately 300%). After incubation, the surface morphology was analyzed using an optical microscope for samples demonstrating the greatest changes over time. The active substance, silymarin, was released using a water bath, and then the antioxidant capacity was determined using the Folin-Ciocâlteu test. The tests carried out proved that the material produced is active and harmless, which was shown by the incubation analysis. The continuous release of the active ingredient increases the biological value of the biomaterial. The material requires further research, including a more detailed assessment of its balance; however, it demonstrates promising potential for further experiments.
- MeSH
- Glucans * chemistry MeSH
- Hydrogen-Ion Concentration MeSH
- Drug Delivery Systems methods MeSH
- Humans MeSH
- Drug Carriers * chemistry MeSH
- Polyethylene Glycols * chemistry MeSH
- Silymarin * chemistry MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
PURPOSE: The aim of this study was to evaluate the antibacterial efficacy of surface-treated hernia implants modified by a hybrid nanolayer with incorporated Ag, Cu, and Zn cations using the sol-gel method. METHODS: The materials (polypropylene, polyester, and polyvinylidene difluoride) were activated by vacuum plasma treatment or UV C radiation, then modified and tested for bacterial strains of Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive). The AATCC 100 (2019) method for quantitative and the ISO 20645 agar plate propagation method for qualitative evaluation of microbiological efficacy were used. The gradual release of incorporated ions was monitored over time in simulated body fluids (blood plasma, peritoneal fluid) and physiological saline using an inductively coupled plasma mass spectrometer. The thickness and the homogeneity of the layers were measured for individual random samples with scanning electron microscope analysis (SEMA) and evaluated with an elemental analysis. RESULTS: Qualitative and quantitative microbiological tests clearly show the great suitability of vacuum plasma and UV C with sol AD30 (dilution 1:1) surface treatment of the implants. The absolute concentration of Ag, Cu, and Zn cations in leachates was very low. SEMA showed a high degree of homogeneity of the layer and only very rare nanocracks by all tested materials appear after mechanical stress. CONCLUSION: This study confirms that surface treatment of meshes using the sol-gel method significantly increases the antibacterial properties. The nanolayers are sufficiently mechanically resistant and stable and pose no threat to health.
- Publication type
- Journal Article MeSH
β-Lactamases (EC 3.5.2.6) confer resistance against β-lactam group-containing antibiotics in bacteria and higher eukaryotes, including humans. Pathogenic bacterial resistance against β-lactam antibiotics is a primary concern for potential therapeutic developments and drug targets. Here, we report putative β-lactamase activity, sulbactam binding (a β-lactam analogue) in the low μM affinity range, and site-specific interaction studies of a 14 kDa UV- and dark-inducible protein (abbreviated as UVI31+, a BolA homologue) from Chlamydomonas reinhartii. Intriguingly, the solution NMR structure of UVI31 + bears no resemblance to other known β-lactamases; however, the sulbactam binding is found at two sites rich in positively charged residues, mainly at the L2 loop regions and the N-terminus. Using NMR spectroscopy, ITC and MD simulations, we map the ligand binding sites in UVI31 + providing atomic-level insights into its β-lactamase activity. Current study is the first report on β-lactamase activity of UVI31+, a BolA analogue, from C. reinhartii. Furthermore, our mutation studies reveal that the active site serine-55 is crucial for β-lactamase activity.
- MeSH
- beta-Lactamases * chemistry metabolism MeSH
- Chlamydomonas reinhardtii * enzymology MeSH
- Magnetic Resonance Spectroscopy methods MeSH
- Nuclear Magnetic Resonance, Biomolecular methods MeSH
- Plant Proteins chemistry metabolism MeSH
- Amino Acid Sequence MeSH
- Molecular Dynamics Simulation MeSH
- Sulbactam chemistry pharmacology MeSH
- Protein Binding MeSH
- Binding Sites MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Venotonics are a class of therapeutically active molecules that have vaso-protective effects. They are used to alleviate venous diseases and disorders, particularly venous insufficiency. We compared the composition of prescription versus over-the-counter (OTC) venotonics using high-performance liquid chromatography with UV detection (HPLC-DAD) and simulating their digestion using a static digestive model. METHODS: From each drug, five tablets were weighed. A homogenate was prepared, and 25 mg of crushed homogenized tablets were weighed into 25 ml volumetric flasks. Dissolved in MeOH and added two drops of saturated NaOH solution. The samples were filtered into vials (Teflon, 0.45 μm) and used for analysis. An Ultimate 3000 HPLC system (Thermo Fisher Scientific, Waltham, MA, USA) consisting of a quaternization pump, autosampler, column thermostat and DAD (UV/VIS detector) was used. The composition of the mobile phase proceeded in a linear gradient from 30% methanol and 70% phosphoric acid (0.15%) in water at time t=0 min. to 80% methanol and 20% phosphoric acid (0.15%) at time t=15 min., at a constant mobile phase flow rate of 1.2 mL/min. Detection was performed using a DAD detector in the 190-450 nm wavelength range. The content of monitored flavonoids was calculated from peaks at a wavelength of 277 nm, in which both flavonoids have their absorption maxima. The static digestive model was used to simulate the digestive phase from the oral cavity to the corresponding intestinal phase. RESULTS: The content of diosmin and hesperidin (mg per table) for a prescription drug: Detralex: 480 mg, 26 mg. The content of diosmin and hesperidin (mg per tablet) for OTC drugs: Venostop: 502 mg, 48 mg, Diosminol: 520 mg, 50 mg, Devenal: 496 mg, 49 mg, Diohes: 493 mg, 46 mg. Digestion did not affect the solubility of all tested drugs. The active substances could not be determined in the non-alkalized sample. After alkalization, part of the insoluble matter was visibly dissolved and converted to a yellow flavonoid complex. Neither diosmin nor hesperidin could be identified afterwards. CONCLUSIONS: Our experimental results show that the contents of both listed active substances, diosmin and hesperidin, met the declared amounts in all tested medicaments. Digestion simulation showed identical behaviour in prescription and OTC venotonics. The active substances could not be determined in the non-alkalized sample. Digestion did not affect the solubility of the tested drugs.
- MeSH
- Models, Biological MeSH
- Diosmin analysis MeSH
- Hesperidin analysis MeSH
- Nonprescription Drugs * chemistry MeSH
- Prescription Drugs analysis chemistry MeSH
- Humans MeSH
- Tablets MeSH
- Chromatography, High Pressure Liquid MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
The chronic exposure of skin to ultraviolet (UV) radiation causes adverse dermal reactions, such as erythema, sunburn, photoaging, and cancer, by altering several signalling pathways associated with oxidative stress, inflammation, and DNA damage. One of the possible UV light protection strategies is the use of dermal photoprotective preparations. The plant hormone kinetin (N6-furfuryladenine; KIN) exhibits antioxidant and anti-senescent effects in human cells. Topically applied KIN also reduced some of the clinical signs of photodamaged skin. To improve the biological activities of KIN, several derivatives have been recently prepared and their beneficial effects on cell viability of skin cells exposed to UVA and UVB light were screened. Two potent candidates, 6-(tetrahydrofuran-2-yl)methylamino-9-(tetrahydrofuran-2-yl)purine (HEO) and 6-(thiophen-2-yl)methylamino-9-(tetrahydrofuran-2-yl)purine (HEO6), were identified. Here the effects of KIN, its N9-substituted derivatives the tetrahydropyran-2-yl derivative of KIN (THP), tetrahydrofuran-2-yl KIN (THF), HEO and HEO6 (both THF derivatives) on oxidative stress, apoptosis and inflammation in UVA- or UVB-exposed skin cell was investigated. Human primary dermal fibroblasts and human keratinocytes HaCaT pre-treated with the tested compounds were then exposed to UVA/UVB light using a solar simulator. All compounds effectively prevented UVA-induced ROS generation and glutathione depletion in both cells. HEO6 was found to be the most potent. All compounds also reduced UVB-induced caspase-3 activity and interleukin-6 release. THP and THF exhibited the best UVB protection. In conclusion, our results demonstrated the UVA- and UVB-photoprotective potential of KIN and its derivatives. From this point of view, they seem to be useful agents for full UV spectrum protective dermatological preparations.
- MeSH
- Antioxidants pharmacology MeSH
- Keratinocytes * metabolism MeSH
- Kinetin metabolism pharmacology MeSH
- Skin * radiation effects MeSH
- Humans MeSH
- Ultraviolet Rays adverse effects MeSH
- Inflammation metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Solar radiation can cause damage to the skin, leading to various adverse effects such as sunburn, reactive oxygen species production, inflammation, DNA damage, and photoaging. To study the potential of photoprotective agents, full-thickness skin models are increasingly being used as in vitro tools. One promising approach to photoprotection involves targeting the redox-sensitive transcription factor Nrf2, which is responsible for regulating various cellular defense mechanisms, including the antioxidant response, inflammatory signaling, and DNA repair. Obacunone, a natural triterpenoid, has been identified as a potent Nrf2 agonist. The present study aims to evaluate the relevance of full-thickness (FT) skin models in photoprotection studies and to explore the potential photoprotective effects of obacunone on those models and in human keratinocytes. Phenion® full-thickness skin models and keratinocytes were incubated with increasing concentrations of obacunone and irradiated with solar-simulated radiation (SSR). Various photodamage markers were evaluated, including histological integrity, oxidative stress, apoptosis, inflammation, photoaging-related dermal markers, and photocarcinogenesis markers. Increasing doses of SSR were found to modulate various biomarkers related to sun damage in the FT skin models. However, obacunone attenuated cytotoxicity, inflammation, oxidative stress, sunburn reaction, photoaging, and photocarcinogenesis in both keratinocytes and full thickness skin models exposed to SSR. These results suggest that obacunone may have potential as a photoprotective agent for preventing the harmful effects of solar radiation on the skin.
- MeSH
- NF-E2-Related Factor 2 genetics MeSH
- Keratinocytes MeSH
- Skin pathology MeSH
- Humans MeSH
- Radiation-Protective Agents * pharmacology MeSH
- Sunburn * MeSH
- Ultraviolet Rays adverse effects MeSH
- Inflammation prevention & control pathology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
The ultraviolet (UV) part of solar radiation can permanently affect skin tissue. UVA photons represent the most abundant UV component and stimulate the formation of intracellular reactive oxygen species (ROS), leading to oxidative damage to various biomolecules. Several plant-derived polyphenols are known as effective photoprotective agents. This study evaluated the potential of quercetin (QE) and its structurally related flavonoid taxifolin (TA) to reduce UVA-caused damage to human primary dermal fibroblasts (NHDF) and epidermal keratinocytes (NHEK) obtained from identical donors. Cells pre-treated with QE or TA (1 h) were then exposed to UVA light using a solar simulator. Both flavonoids effectively prevented oxidative damage, such as ROS generation, glutathione depletion, single-strand breaks formation and caspase-3 activation in NHDF. These protective effects were accompanied by stimulation of Nrf2 nuclear translocation, found in non-irradiated and irradiated NHDF and NHEK, and expression of antioxidant proteins, such as heme oxygenase-1, NAD(P)H:quinone oxidoreductase 1 and catalase. For most parameters, QE was more potent than TA. On the other hand, TA demonstrated protection within the whole concentration range, while QE lost its protective ability at the highest concentration tested (75 μM), suggesting its pro-oxidative potential. In summary, QE and TA demonstrated UVA-protective properties in NHEK and NHDF obtained from identical donors. However, due to the in vitro phototoxic potential of QE, published elsewhere and discussed herein, further studies are needed to evaluate QE safety in dermatological application for humans as well as to confirm our results on human skin ex vivo and in clinical trials.
- MeSH
- Fibroblasts MeSH
- Flavonoids * metabolism MeSH
- Keratinocytes MeSH
- Skin metabolism MeSH
- Humans MeSH
- Oxidative Stress MeSH
- Quercetin * analogs & derivatives pharmacology MeSH
- Ultraviolet Rays MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
