Nrf2- and Bach1 May Play a Role in the Modulation of Ultraviolet A-Induced Oxidative Stress by Acetyl-11-Keto-β-Boswellic Acid in Skin Keratinocytes

The Multifaceted Roles of BACH1 in Disease: Implications for Biological Functions and Therapeutic Applications

BTB domain and CNC homolog 1 (BACH1) belongs to the family of basic leucine zipper proteins and is expressed in most mammalian tissues. It can regulate its own expression and play a role in transcriptionally activating or inhibiting downstream target genes. It has a crucial role in various biological processes, such as oxidative stress, cell cycle, heme homeostasis, and immune regulation. Recent research highlights BACH1's significant regulatory roles in a series of conditions, including stem cell pluripotency maintenance and differentiation, growth, senescence, and apoptosis. BACH1 is closely associated with cardiovascular diseases and contributes to angiogenesis, atherosclerosis, restenosis, pathological cardiac hypertrophy, myocardial infarction, and ischemia/reperfusion (I/R) injury. BACH1 promotes tumor cell proliferation and metastasis by altering tumor metabolism and the epithelial-mesenchymal transition phenotype. Moreover, BACH1 appears to show an adverse role in diseases such as neurodegenerative diseases, gastrointestinal disorders, leukemia, pulmonary fibrosis, and skin diseases. Inhibiting BACH1 may be beneficial for treating these diseases. This review summarizes the role of BACH1 and its regulatory mechanism in different cell types and diseases, proposing that precise targeted intervention of BACH1 may provide new strategies for human disease prevention and treatment.

Effect of Boswellic acids on T cell proliferation and activation

Boswellic acids have been recognized as anti-inflammatory and immunomodulatory agents with potentials to control autoimmune and inflammatory diseases. However, their effects on T cell proliferation and activation are not fully elucidated. In this study, we investigated effects of individual compounds including β-Boswellic acids (β-BA), 11-keto-β-Boswellic acid (β-KBA), 3-O-acetyl β-Boswellic acids (β-ABA), and 3-O-acetyl-11-keto-β-Boswellic acid (β-AKBA) on human peripheral blood mononuclear cells (PBMCs) and their potential role in modulating immune responses. We showed that β-BA, KBA, and AKBA at a 0.025 µM concentration significantly reduced T cell proliferation without inducing cytotoxicity, however, ABA showed cytotoxic effects at this concentration. β-BA and KBA showed significantly reduced T cell proliferation at 0.05 µM concentration without cytotoxic effects. Interestingly, we found that AKBA at 0.025 µM concentration significantly reduced CD25 expression on both CD4+ and CD8+ T cells without cytotoxic effects. Additionally, β-BA reduced CD25 expression on both CD4+ and CD8+ T cells at 0.05 µM concentration with no cytotoxicity. In this study, we determined the optimum concentration of each of these compounds that have the potential to reduce T cell activation without cytotoxic effects. Our findings show that both β-BA and AKBA have the ability to inhibit T cell proliferation and activation without inducing cytotoxicity. Further investigations are required to fully understand the mechanisms underlying these effects and the potential therapeutic benefits of these compounds in different autoimmune and inflammatory settings.

The Protective Effect of 11-Keto-β-Boswellic Acid against Diabetic Cardiomyopathy in Rats Entails Activation of AMPK

This study examined the protective effect of 11-keto-β-boswellic acid (AKBA) against streptozotocin (STZ)-induced diabetic cardiomyopathy (DC) in rats and examined the possible mechanisms of action. Male rats were divided into 5 groups (n = 8/each): (1) control, AKBA (10 mg/kg, orally), STZ (65 mg/kg, i.p.), STZ + AKBA (10 mg/kg, orally), and STZ + AKBA + compound C (CC/an AMPK inhibitor, 0.2 mg/kg, i.p.). AKBA improved the structure and the systolic and diastolic functions of the left ventricles (LVs) of STZ rats. It also attenuated the increase in plasma glucose, plasma insulin, and serum and hepatic levels of triglycerides (TGs), cholesterol (CHOL), and free fatty acids (FFAs) in these diabetic rats. AKBA stimulated the ventricular activities of phosphofructokinase (PFK), pyruvate dehydrogenase (PDH), and acetyl CoA carboxylase (ACC); increased levels of malonyl CoA; and reduced levels of carnitine palmitoyltransferase I (CPT1), indicating improvement in glucose and FA oxidation. It also reduced levels of malondialdehyde (MDA); increased mitochondria efficiency and ATP production; stimulated mRNA, total, and nuclear levels of Nrf2; increased levels of glutathione (GSH), heme oxygenase (HO-1), superoxide dismutase (SOD), and catalase (CAT); but reduced the expression and nuclear translocation of NF-κB and levels of tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These effects were concomitant with increased activities of AMPK in the LVs of the control and STZ-diabetic rats. Treatment with CC abolished all these protective effects of AKBA. In conclusion, AKBA protects against DC in rats, mainly by activating the AMPK-dependent control of insulin release, cardiac metabolism, and antioxidant and anti-inflammatory effects.

Nrf2/HO-1 Signaling Stimulation through Acetyl-11-Keto-Beta-Boswellic Acid (AKBA) Provides Neuroprotection in Ethidium Bromide-Induced Experimental Model of Multiple Sclerosis

Multiple sclerosis (MS) is a severe immune-mediated neurological disease characterized by neuroinflammation, demyelination, and axonal degeneration in the central nervous system (CNS). This is frequently linked to motor abnormalities and cognitive impairments. The pathophysiological hallmarks of MS include inflammatory demyelination, axonal injury, white matter degeneration, and the development of CNS lesions that result in severe neuronal degeneration. Several studies suggested downregulation of nuclear factor erythroid-2-related factor-2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling is a causative factor for MS pathogenesis. Acetyl-11-keto-β-boswellic acid (AKBA) is an active pentacyclictriterpenoid obtained from Boswellia serrata, possessing antioxidant and anti-inflammatory properties. The present study explores the protective potential of AKBA on behavioral, molecular, neurochemical, and gross pathological abnormalitiesandhistopathological alterations by H&E and LFB staining techniques in an experimental model of multiple sclerosis, emphasizing the increase inNrf2/HO-1 levels in the brain. Moreover, we also examine the effect of AKBA on the intensity of myelin basic protein (MBP) in CSF and rat brain homogenate. Specific apoptotic markers (Bcl-2, Bax, andcaspase-3) were also estimated in rat brain homogenate. Neuro behavioralabnormalities in rats were examined using an actophotometer, rotarod test, beam crossing task (BCT),and Morris water maze (MWM). AKBA 50 mg/kg and 100 mg/kg were given orally from day 8 to 35 to alleviate MS symptoms in the EB-injected rats. Furthermore, cellular, molecular, neurotransmitter, neuroinflammatory cytokine, and oxidative stress markers in rat whole brain homogenate, blood plasma, and cerebral spinal fluid were investigated. This study shows that AKBA upregulates the level of antioxidant proteins such as Nrf2 and HO-1 in the rat brain. AKBA restores altered neurochemical levels, potentially preventing gross pathological abnormalities during MS progression.

Acetyl-11-Keto-Beta Boswellic Acid (AKBA) Protects Lens Epithelial Cells Against H2O2-Induced Oxidative Injury and Attenuates Cataract Progression by Activating Keap1/Nrf2/HO-1 Signaling

Age-related cataract (ARC) is one of the leading blinding eye diseases worldwide. Chronic oxidative stress and the apoptosis of human lens epithelial cells (HLECs) have been suggested to be the mechanism underlying cataract formation. Acetyl-11-keto-β-boswellic acid (AKBA) is a pentacyclic triterpene with antioxidative and antiapoptotic effects. In this study, we investigated the potential effects of AKBA on oxidative-induced HLECs injury and cataract formation. H₂O₂ was used to simulate HLECs oxidative injury in vitro, and Na₂SeO₃ was applied to establish an in vivo cataract model. In our current study, a cell counting kit-8 (CCK-8) assay was performed to evaluate the effects of H₂O₂ and AKBA on cell viability in vitro. Intracellular reactive oxygen species (ROS) levels were measured with the ROS assay to verify the antioxidant capacity of AKBA. Apoptotic cells were detected and measured by TUNEL staining and flow cytometry, and quantitative real-time (qRT)-PCR and Western blotting were applied to examine the transcription and expression of apoptosis-related proteins. Furthermore, immunofluorescence staining was performed to locate factor-erythroid 2-related factor 2 (Nrf2), and the protein levels of Nrf2, kelch-like ECH-associated protein 1 (Keap1) and heme oxygenase-1 (HO-1) were determined by Western blotting. Finally, we observed the degree of lens opacity and performed hematoxylin-eosin (H&E) staining to assess the protective effect of AKBA on cataract formation in vivo. AKBA increased HLECs viability under H₂O₂ stimulation, decreased intracellular ROS levels and alleviated the cell apoptosis rate in vitro. AKBA significantly decreased the expression of caspase-3 and Bax and increased the content of Bcl-2. The results of immunofluorescence and immunohistochemical staining proved that the expression and nuclear translocation of Nrf2 were activated with AKBA treatment in vivo and in vitro. Moreover, computational docking results showed that AKBA could bind specifically to the predicted Keap1/Nrf2 binding sites. After AKBA activation, Nrf2 dissociates from the Nrf2/Keap1 complex, translocates into the nucleus, and subsequently promotes HO-1 expression. In addition, AKBA attenuated lens opacity in selenite-induced cataracts. Overall, these findings indicated that AKBA alleviated oxidative injury and cataract formation by activating the Keap1/Nrf2/HO-1 cascade. Therefore, our current study highlights that AKBA may serve as a promising treatment for ARC progression.

Eriodictyol protects skin cells from UVA irradiation-induced photodamage by inhibition of the MAPK signaling pathway

Solar UVA irradiation-generated reactive oxygen species (ROS) induces the expression of matrix metalloproteinase 1 (MMP-1), leading to photoaging, however the molecular mechanism remains unclear. In the present study, we found that eriodictyol remarkably reduces UVA-mediated ROS generation and protects the skin cells from oxidative damage and the ensuing cell death. Moreover eriodictyol pretreatment significantly down-regulates the UVA-induced MMP-1 expression, and lowers the inflammatory responses within the skin cells. Pretreatment with eriodictyol upregulates the expression of tissue inhibitory metalloproteinase 1 (TIMP-1) and collagen-I (COL-1) at the transcriptional level in a dose-dependent manner. UVA-induced phosphorylation levels of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38 leading to increased MMP-1 expression are significantly reduced in eriodictyol-treated skin cells. In addition, eriodictyol pretreatment significantly suppresses inflammatory cytokines and inhibits the activation of MAPK signaling cascades in skin cells. Taken together, our results demonstrate that eriodictyol has both potent anti-inflammatory and anti-photoaging effects.

Development of Iron Sequester Antioxidant Quercetin@ZnO Nanoparticles with Photoprotective Effects on UVA-Irradiated HaCaT Cells

BACKGROUND

Solar ultraviolet radiation A (UVA, 320-400 nm) is a significant risk factor leading to various human skin conditions such as premature aging or photoaging. This condition is enhanced by UVA-mediated iron release from cellular iron proteins affecting huge populations across the globe.

PURPOSE

Quercetin-loaded zinc oxide nanoparticles (quercetin@ZnO NPs) were prepared to examine its cellular iron sequestration ability to prevent the production of reactive oxygen species (ROS) and inflammatory responses in HaCaT cells.

METHODS

Quercetin@ZnO NPs were synthesized through a homogenous precipitation method, and the functional groups were characterized by Fourier transform infrared (FTIR) spectroscopy, whereas scanning electron microscopy (SEM) described the morphologies of NPs. MTT and qRT-PCR assays were used to examine cell viability and the expression levels of various inflammatory cytokines. The cyclic voltammetry (CV) was employed to evaluate the redox potential of quercetin-Fe3+/quercetin-Fe2+ complexes.

RESULTS

The material characterization results supported the loading of quercetin molecules on ZnO NPs. The CV and redox potential assays gave Fe-binding capability of quercetin at 0.15 mM and 0.3 mM of Fe(NO3)3. Cytotoxicity assays using quercetin@ZnO NPs with human HaCaT cells showed no cytotoxic effects and help regain cell viability loss following UVA (150 kJ/m2).

CONCLUSION

Quercetin@ZnO NPs showed that efficient quercetin release action is UV-controlled, and the released quercetin molecules have excellent antioxidant, anti-inflammatory, and iron sequestration potential. Quercetin@ZnO NPs have superior biocompatibility to provide UVA protection and medication at once for antiphotoaging therapeutics.

Effect of ultraviolet radiation on the Nrf2 signaling pathway in skin cells

PURPOSE

Excessive exposure of skin to solar radiation is associated with greatly increased production of reactive oxygen and nitrogen species (ROS, RNS) resulting in oxidative stress (OS), inflammation, immunosuppression, the production of matrix metalloproteinase, DNA damage and mutations. These events lead to increased incidence of various skin disorders including photoaing and both non-melanoma and melanoma skin cancers. The ultraviolet (UV) part of sunlight, in particular, is responsible for structural and cellular changes across the different layers of the skin. Among other effects, UV photons stimulate oxidative damage to biomolecules via the generation of unstable and highly reactive compounds. In response to oxidative damage, cytoprotective pathways are triggered. One of these is the pathway driven by the nuclear factor erythroid-2 related factor 2 (Nrf2). This transcription factor translocates to the nucleus and drives the expression of numerous genes, among them various detoxifying and antioxidant enzymes. Several studies concerning the effects of UV radiation on Nrf2 activation have been published, but different UV wavelengths, skin cells or tissues and incubation periods were used in the experiments that complicate the evaluation of UV radiation effects.

CONCLUSIONS

This review summarizes the effects of UVB (280-315 nm) and UVA (315-400 nm) radiation on the Nrf2 signaling pathway in dermal fibroblasts and epidermal keratinocytes and melanocytes. The effects of natural compounds (pure compounds or mixtures) on Nrf2 activation and level as well as on Nrf2-driven genes in UV irradiated human skin fibroblasts, keratinocytes and melanocytes are briefly mentioned as well.HighlightsUVB radiation is a rather poor activator of the Nrf2-driven pathway in fibroblastsUVA radiation stimulates Nrf2 activation in dermal fibroblastsEffects of UVA on the Nrf2 pathway in keratinocytes and melanocytes remain unclearLong-term Nrf2 activation in keratinocytes disturbs their normal differentiationPharmacological activation of Nrf2 in the skin needs to be performed carefully.

Expression of nuclear factor erythroid-2-related factor 2, broad complex-tramtrack-bric a brac and Cap'n'collar homology 1 and γ-glutamic acid cysteine synthase in peripheral blood of patients with chronic obstructive pulmonary disease and its clinical significance

The purpose of the present study was to explore the relationship between nuclear factor erythroid 2-related factor 2 (Nrf2)/BTB-CNC allogeneic 1 (Bach1)/γ-glutamic acid cysteine synthase (γ-GCS) and chronic obstructive pulmonary disease (COPD). The expression of Nrf2, Bach1, γ-GCS mRNA and protein in the peripheral blood mononuclear cells (PBMCs) of 80 COPD patients and 40 healthy volunteers were studied. Then, the correlation between Nrf2, Bach1, γ-GCS and lung function, inflammation and oxidative stress indicators was analyzed. Compared with healthy controls, Nrf2, Bach1 mRNA and protein levels were significantly increased in the PBMCs of COPD patients, while γ-GCS mRNA and protein levels were significantly decreased. Nrf2 and Bach1 protein levels in the nucleus were significantly elevated in acute exacerbation COPD patients compared with patients with a stable stage of COPD, while γ-GCS mRNA levels were significantly reduced. In addition, it was found that Nrf2 nuclear protein levels were significantly reduced in COPD patients compared with the control group, while Bach1 nuclear protein levels were significantly increased. Correlation analysis in COPD group demonstrated that γ-GCS mRNA was positively correlated with Nrf2 nuclear protein level, but negatively correlated with Bach1 nuclear protein level. Further analysis demonstrated that γ-GCS mRNA and Nrf2 protein in the nucleus was positively correlated with forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC)% and FEV₁% predicted, and Bach1 protein in the nucleus was negatively correlated with FEV₁/FVC% and FEV₁% predicted. Additionally, the expression levels of Nrf2, Bach1 and γ-GCS were also associated with smoking. The expression of Nrf2, Bach1 and γ-GCS in peripheral blood mononuclear cells of patients with COPD was dysregulated and related to lung function, which provides a new basis for exploring further the pathogenesis of COPD.

Effect of UVA radiation on the Nrf2 signalling pathway in human skin cells

The harmful effects of low energy UVA photons (315-400 nm) are associated with the massive production of reactive oxygen species resulting in oxidative stress. In response to oxidative damage, NF-E2-related factor 2 (Nrf2) is translocated to the nucleus and drives the expression of detoxication and antioxidant enzymes. UVA's effect on Nrf2 has been quite well characterised in dermal fibroblasts. However, there is a dearth of such information for keratinocytes. This study aimed to evaluate and compare the effect of UVA radiation on the Nrf2 pathway and oxidative stress related proteins in primary human dermal fibroblasts (NHDF), epidermal keratinocytes (NHEK) and human keratinocyte cell line HaCaT. NHDF were exposed to doses of 2.5-7.5 J/cm², NHEK and HaCaT to 10-20 J/cm² using a solar simulator. Effects on Nrf2 translocation were evaluated after 1, 3 and 6 h and Nrf2-controlled proteins (heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione reductase (GSR), glutathione-S-transferase (GST), interleukine-6 (IL-6), and matrix metalloproteinases (MMP-1, MMP-2)) after 3, 6 and 24 h. The results showed the fastest Nrf2 translocation was in UVA-irradiated HaCaT (1 h), persisting until the subsequent time interval (3 h), while in primary keratinocytes the effect of radiation was minimal. In NHDF, UVA-stimulated Nrf2 translocation was conspicuous 3 h after UVA treatment. In NHDF, most of the studied proteins (NQO1, HO-1, GSR, GSTM1 and MMP-1) showed the highest level 24 h after UVA exposure, except for MMP-2 and IL-6 which had their highest level at a shorter time incubation interval (3 h). In NHEK, NQO1, HO-1 and GST were increased 6 h after UVA exposure, GSR and MMP-2 level was slightly below or above the control level, and MMP-1 and IL-6 increased at shorter time intervals. When comparing NHEK and HaCaT, these cells displayed contrary responses in most of the Nrf2-controlled proteins. Thus, primary keratinocytes cannot be replaced with HaCaT when studying cell signalling such as the Nrf2 driven pathway and Nrf2-controlled proteins.

Resveratrol protects against CIH-induced myocardial injury by targeting Nrf2 and blocking NLRP3 inflammasome activation

The prominent feature of obstructive sleep apnea (OSA) is chronic intermittent hypoxia (CIH). Given the strong antioxidant ability of resveratrol against oxidative stress, we evaluated the potential protective effects of resveratrol on myocardial injury induced by CIH. Twenty-four rats were divided into normal control group, CIH group, CIH plus resveratrol treated (CIH + Res) group, and resveratrol treated control (Res) group. We proved that CIH impaired cardiac structure and function with an increase in oxidative stress, endoplasmic reticulum (ER) stress and NOD-like receptors (NLRP3) inflammasome induction in heart, which was attenuated after resveratrol administration. NLRP3 inflammasome blockade by resveratrol appeared to be mediated by activating AMP-activated Protein Kinase (AMPK), which could restrain mTOR/TTP/NLRP3 mRNA signalling. Furthermore, resveratrol attenuated CIH-induced oxidative stress through elevation antioxidant molecules expression via NF-E2-related factor-2 (Nrf2). Moreover, AMPK may play a role in Nrf2/HO-1 signalling by resveratrol. These results expand our understanding of the myocardial protective mechanism of resveratrol during CIH and suggest that resveratrol treatment may be useful to counteract OSA-associated cardiac injury.

Heme Oxygenases: Cellular Multifunctional and Protective Molecules against UV-Induced Oxidative Stress

Ultraviolet (UV) irradiation can be considered as a double-edged sword: not only is it a crucial environmental factor that can cause skin-related disorders but it can also be used for phototherapy of skin diseases. Inducible heme oxygenase-1 (HO-1) in response to a variety of stimuli, including UV exposure, is vital to maintain cell homeostasis. Heme oxygenase-2 (HO-2), another member of the heme oxygenase family, is constitutively expressed. In this review, we discuss how heme oxygenase (HO), a vital rate-limiting enzyme, participates in heme catabolism and cytoprotection. Phylogenetic analysis showed that there may exist a functional differentiation between HO-1 and HO-2 during evolution. Furthermore, depending on functions in immunomodulation and antioxidation, HO-1 participates in disease progression, especially in pathogenesis of skin diseases, such as vitiligo and psoriasis. To further investigate the particular role of HO-1 in diseases, we summarized the profile of the HO enzyme system and its related signaling pathways, such as Nrf2 and endoplasmic reticulum crucial signaling, both known to regulate HO-1 expression. Furthermore, we report on a C-terminal truncation of HO-1, which is generally considered as a signal molecule. Also, a newly identified alternative splice isoform of HO-1 not only provides us a novel perspective on comprehensive HO-1 alternative splicing but also offers us a basis to clarify the relationship between HO-1 transcripts and oxidative diseases. To conclude, the HO system is not only involved in heme catabolism but also involved in biological processes related to the pathogenesis of certain diseases, even though the mechanism of disease progression still remains sketchy. Further understanding the role of the HO system and its relationship to UV is helpful for revealing the HO-related signaling networks and the pathogenesis of many diseases.

UV-responsive AKBA@ZnO nanoparticles potential for polymorphous light eruption protection and therapy

Polymorphous light eruption (PLE) is one of the acquired idiopathic photodermatosis mainly induced by immoderate UV radiation. In order to realize UV protection and medicine administration simultaneously for polymorphous light eruption protection and therapy, Acetyl-11-keto-β-boswellic acid (AKBA) loaded Zinc Oxide (ZnO) nanoparticles of which drug release behavior is UV-controlled has been successfully synthesized. Such nanoparticles can not only reflect UV but also transfer the energy to release AKBA which presents an excellent antioxidant and anti-inflammatory effects. In addition, they are biocompatible to HaCaT cells. As a result, they have a great potential in combining UV protection and medicine administration simultaneously for PLE protection and therapy.

Atopic Patients Show Increased Interleukin 4 Plasma Levels but the Degree of Elevation Is Not Sufficient to Upregulate Interleukin-4-Sensitive Genes

BACKGROUND

Atopic diseases constitute a major health challenge for industrialized countries, and elevated levels of interleukin 4 (IL-4) frequently characterize these disorders. Previous in vitroanalyses have indicated that IL-4 strongly upregulates the expression of IL-4-sensitive genes in human monocytes.

OBJECTIVE

To explore whether similar expression alterations may contribute to the pathomechanisms of atopic diseases in vivo we carried out a small-scale case-control clinical study (n = 43), in which we quantified the plasma levels of IgE and IL-4 as well as the expression of selected IL-4-sensitive genes in blood leukocytes.

METHODS

34 allergic patients suffering from allergic rhinitis (n = 11), atopic eczema (n = 11) and allergic asthma (n = 12) as well as 9 healthy control individuals were recruited. IgE and IL-4 plasma levels were determined by ELISA, and the expression of selected IL-4-sensitive gene products in blood leukocytes was quantified by qRT-PCR. In addition, the fatty acid oxygenase activity of isolated monocytes was measured by RP-HPLC analysis of the arachidonic acid oxygenation products (ex vivo activity assays).

RESULTS

We found that plasma levels of IgE and IL-4 were significantly elevated in atopic patients but the degree of elevation was not sufficient to upregulate the expression of the selected IL-4-sensitive genes in circulating leukocytes. Moreover, the arachidonic acid oxygenase activity of blood monocytes was not significantly altered in atopic patients.

CONCLUSION

Our data suggest that the IL-4 plasma levels of atopic patients are not high enough to impact the expression of IL-4-sensitive genes.

Dehydroabietic Acid Induces Regeneration of Collagen Fibers in Ultraviolet B-Irradiated Human Dermal Fibroblasts and Skin Equivalents

BACKGROUND/AIMS

Dehydroabietic acid (DAA) is a natural phytochemical found in red pine trees and herbal plants. While DAA and its derivatives are known for improving diabetes and hyperlipidemia, the antiaging effect and its underlying mechanisms of DAA on skin have not been fully examined. Here, we assessed the antiaging effects of DAA on human dermal fibroblasts and skin equivalents.

METHODS

We investigated the effect of DAA on the secretion of type I procollagen and matrix metalloproteinase-1 (MMP-1) in ultraviolet B (UVB)-irradiated neonatal normal human dermal fibroblasts (NHDFn). Using nonlinear optical imaging techniques, we visualized quantitative and qualitative changes of collagen fibers by DAA treatment in human skin equivalent models.

RESULTS

DAA induces increases in type I procollagen secretion when treated on UVB-irradiated NHDFn. DAA also downregulates secretion of MMP-1 through the inhibition of the JNK signaling pathway. In human skin equivalent models, we successfully visualized the spatial distribution of collagen fibers in the dermis and found that quantity, diameter, and arrangement of collagen fibers in the dermis were significantly improved by DAA treatment.

CONCLUSION

Our results suggest that DAA could be a useful agent for improving skin photoaging through the protection and regeneration of collagen fibers in skin.

Label-free electrochemical sensor to investigate the effect of tocopherol on generation of superoxide ions following UV irradiation

Background

Generation of reactive oxygen species (ROS), triggered by ultraviolet radiation (UVR), is associated with carcinogenesis of the skin. UV irradiation induced superoxide anion (O2^•−) is the key ROS involved in the cellular damage. The cytoprotective efficacy of an unknown anti-oxidant compound can be evaluated by analyzing the production of O2^•− from treated cells.

Methods

In this study, a glass carbon electrode functionalized with nanotube@DNA-Mn3(PO4)2 composite was applied to quantitative determination of generation of highly unstable O2^•− from the melanoma A375 cell line following UVR(UV, UVA and UVB). In addition, the cytoprotective efficacy of anti-oxidant α-tocopherol was evaluated by quantifying the production of O2^•−.

Results

The results showed that, UVR triggers generation of O2^•− in melanoma A375 cells, and α-tocopherol is effective in diminishing the production of O2^•− following UV irradiation. By comparing the conventional cell-survival assays results, we found that our simple and quick electrochemical sensing method can quantify O2^•− generation through the biological activity of an anti-oxidant compound (α-tocopherol).

Conclusion

Our label-free electrochemical quantification method for ROS (O2^•− major) in cells facing UVR stress demonstrates its potential application for high-throughput screening of anti-oxidation compounds.

Lycium barbarum polysaccharide protects HSF cells against ultraviolet-induced damage through the activation of Nrf2

Background

Lycium barbarum polysaccharide (LBP) is considered an antioxidant agent. NF-E2-related factor-2 (Nrf2) is an important regulator for protection against UV damage. In this study, we verified the performance of LBP and the correlation between LBP and Nrf2.

Methods

HSF cells were treated with LBP to determine dose and time dependencies. An antioxidant response element (ARE) reporter was designed to monitor the activity of the Nrf2 antioxidant pathway.

Results

For HSF cells, the optimal LBP treatment was 300 μg/ml for 3 h. The ARE-reporter assay showed that LBP could increase the robustness of p-Nrf2. Treatments with genistein and LY294002 reduced of nuclear p-Nrf2 after 24 h. LBP increased the level of nuclear Nrf2, which functions by both phosphorylation and nuclear translocation. Silencing Nrf2 led to increased reactive oxygen species (ROS) levels, lower cell viability, and decreased superoxide dismutase (SOD) and glutathione peroxidase (GSP-PX) levels. This induced a higher level of lipid peroxide (LPO). However, LBP could decrease the levels of ROS and LPO and enhance the levels of SOD and GSP-PX.

Conclusion

LBP protects HSF cells against UV damage via the regulation of Nrf2.