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

Photoprotective Effects of Epigallocatechin Gallate on Ultraviolet-Induced Zebrafish and Human Skin Fibroblasts Cells

Background

The long-term exposure to ultraviolet radiation (UVR) raises oxidative stress and chronic inflammation levels, which in turn has a series of deleterious effects on skin health, such as sunburn, photoaging, and skin cancer. Hence, our study was determined to investigate the effects and mechanisms of epigallocatechin gallate (EGCG) in zebrafish and human skin fibroblasts (HSF) cells to alleviate ultraviolet-induced photoaging.

Methods

The 4 days postfertilization (dpf) zebrafish larvae and HSF cells were treated with 10 J/cm2 UVA + 30 mJ/cm2 UVB, or 25, or 50 μM EGCG for 72 hr. The indicators involving in oxidative stress, inflammatory, and photoaging were measured by the kits, ELISA Kits and western blot methods.

Results

EGCGs protect against UVR-induced skin damage in zebrafish and HSF cells. EGCG markedly decreased the reactive oxygen species (ROS), malondialdehyde, 8-OHdG levels, increased superoxide dismutase (SOD) activity, and significantly inhibited inflammatory factors levels including tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), interleukin-6 (IL-6) in zebrafish, and HSF cells irradiated with UVR. We found that EGCG could reduce UVR-induced p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation and effectively inhibited the activity of the transcriptional factor nuclear factor-κB (NF-κB), thereby reducing the protein-1 (AP-1), TNF-α, IL-1α, IL-6, and matrix metalloproteinase-1 (MMP-1) expressions, which are critical mediators of skin aging cascade causing the photoaging.

Conclusion

These results validate that EGCG for protection of photoaging in zebrafish and HSF cells induced by UVR, which is closely related to the regulation of p38 MAPK/NF-κB, AP-1 signaling pathway which relieve oxidative stress, inflammation, and collagen degradation.

Exosomes from hypoxic pretreated ADSCs attenuate ultraviolet light-induced skin injury via GLRX5 delivery and ferroptosis inhibition

Accumulation studies have found that adipose-derived stem cell (ADSC) exosomes have anti-oxidant and anti-inflammatory characteristics. The current study verified their therapeutic potential to elucidate mechanisms of ADSC exosome actions in ultraviolet B (UVB) light-induced skin injury. Exosomes were isolated from ADSCs and hypoxic pretreated ADSCs. Next-generation sequencing (NGS) was applied to characterize differential mRNA expression. A UV-induced mice skin injury model was generated to investigate therapeutic effects regarding the exosomes via immunofluorescence and ELISA analysis. Regulatory mechanisms were illustrated using luciferase report analysis and in vitro experiments. The results demonstrated that exosomes from hypoxic pretreated ADSCs (HExos) inhibited UVB light-induced vascular injury by reversing reactive oxygen species, inflammatory factor expression and excessive collagen degradation. NGS showed that HExos inhibits UV-induced skin damage via GLRX5 delivery, while GLRX5 downregulation inhibited the therapeutic effect of HExos on UV-induced skin damage. GLRX5 upregulation increased the protective Exo effect on UV-induced skin and EPC damage by inhibiting ferroptosis, inflammatory cytokine expression and excessive collagen degradation. Therefore, the data indicate that HExos attenuate UV light-induced skin injury via GLRX5 delivery and ferroptosis inhibition.

Neuroprotective effects of Lycium barbarum polysaccharide on light-induced oxidative stress and mitochondrial damage via the Nrf2/HO-1 pathway in mouse hippocampal neurons

Light at night (LAN) induced cognitive impairment associated with oxidative stress in mice has been reported. Lycium barbarum polysaccharide (LBP) exhibits anti-tumor, anti-oxidant and neuroprotective effects, yet the neuroprotective effect on light-induced neuron damage still unclear. Here, mice exposed to LAN displayed cognitive impairment and depressive like behavior, which was reversed by LBP treatment. Meanwhile, LBP alleviated light-induced higher apoptosis and mitochondrial damage in HT-22 cells. Also, LBP prevented the decreased of mitochondrial membrane permeabilization (MMP) level in light-treated cells. Additionally, LBP demonstrated its antioxidant potential by reducing ROS production and malondialdehyde (MDA) level, while simultaneously enhancing the levels of superoxide dismutase (SOD) and glutathione peroxidases (GSH-Px) in both light-treated mice and HT-22 cells. Furthermore, the mRNA and protein expression of Nrf2 (NF-E2-related factor 2), heme oxygenease-1 (HO-1), and NAD(P)H quinone oxidoreductase (NQO1) were decreased in both light-treated mice and cells. Additionally, LBP treatment reversed light-induced the inhibition of Nrf2/HO-1 signaling pathway in both mice and cells. Moreover, Nrf2 antagonist ML385 significantly eliminated the neuroprotection of LBP on cell apoptosis, oxidative stress and mitochondrial damage in light-treated cells. These results indicate that LBP can rescue light-induced neurotoxicity in mice and HT-22 cells by activating the Nrf2/HO-1 signaling pathway.

Combined Lycium barbarum Polysaccharides with Plasmon-Activated Water Affect IFN-γ/TNF-α Induced Inflammation in Caco-2 Cells

The effects of Lycium barbarum polysaccharides (LBP) and plasmon-activated water (PAW) against IFN-γ/TNF-α induced inflammation in human colon Caco-2 cells were investigated. Cells were divided into the control, induction, LBP treatment (100-500 μg/mL), and combination groups with PAW. Inflammation was induced 24 h with 10 ng/mL IFN-γ when cell confluency reached >90%, and various doses of LBP with or without PAW were treated for 3 h, and subsequently 50 ng/mL TNF-α was added for another 24 h to provoke inflammation. Combination of LBP with PAW significantly decreased the secretion of IL-6 and IL-8. Cyclooxygenase-2 and inducible NO synthase expression was attenuated in all LBP-treated groups with or without PAW. NLRP3 inflammasome and related protein PYCARD expression were inhibited by LBP at the highest dose (500 μg/mL). All doses of LBP alone significantly decreased p-ERK expression, but combination with PAW increased p-ERK expression compared to those without PAW. Additionally, 250 and 500 μg/mL of LBP with or without PAW inhibited procaspase-3/caspase-3 expression. Therefore, LBP possesses anti-inflammation and anti-apoptosis by inhibiting the secretion of inflammatory cytokines and the expression of NLRP3 inflammasome-related protein. The combination with PAW exerts additive or synergistic effect on anti-inflammation.

Distinct Role of Lycium barbarum L. Polysaccharides in Oxidative Stress-Related Ocular Diseases

Oxidative stress is an imbalance between the increased production of reactive species and reduced antioxidant activity, which can cause a variety of disturbances including ocular diseases. Lycium barbarum polysaccharides (LBPs) are complex polysaccharides isolated from the fruit of L. barbarum, showing distinct roles in antioxidants. Moreover, it is relatively safe and non-toxic. In recent years, the antioxidant activities of LBPs have attracted remarkable attention. In order to illustrate its significance and underlying therapeutic value for vision, we comprehensively review the recent progress on the antioxidant mechanisms of LBP and its potential applications in ocular diseases, including diabetic retinopathy, hypertensive neuroretinopathy, age-related macular degeneration, retinitis pigmentosa, retinal ischemia/reperfusion injury, glaucoma, dry eye syndrome, and diabetic cataract.

Advances in health-promoting effects of natural polysaccharides: Regulation on Nrf2 antioxidant pathway

Natural polysaccharides (NPs) possess numerous health-promoting effects, such as liver protection, kidney protection, lung protection, neuroprotection, cardioprotection, gastrointestinal protection, anti-oxidation, anti-diabetic, and anti-aging. Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway is an important endogenous antioxidant pathway, which plays crucial roles in maintaining human health as its protection against oxidative stress. Accumulating evidence suggested that Nrf2 antioxidant pathway might be one of key regulatory targets for the health-promoting effects of NPs. However, the information concerning regulation of NPs on Nrf2 antioxidant pathway is scattered, and NPs show different regulatory behaviors in their different health-promoting processes. Therefore, in this article, structural features of NPs having regulation on Nrf2 antioxidant pathway are overviewed. Moreover, regulatory effects of NPs on this pathway for health-promoting effects are summarized. Furthermore, structure-activity relationship of NPs for health-promoting effects by regulating the pathway is preliminarily discussed. Otherwise, the prospects on future work for regulation of NPs on this pathway are proposed. This review is beneficial to well-understanding of underlying mechanisms for health-promoting effects of NPs from the view angle of Nrf2 antioxidant pathway, and provides a theoretical basis for the development and utilization of NPs in promoting human health.

Antioxidant Activities of Natural Polysaccharides and Their Derivatives for Biomedical and Medicinal Applications

Many chronic diseases such as Alzheimer's disease, diabetes, and cardiovascular diseases are closely related to in vivo oxidative stress caused by excessive reactive oxygen species (ROS). Natural polysaccharides, as a kind of biomacromolecule with good biocompatibility, have been widely used in biomedical and medicinal applications due to their superior antioxidant properties. In this review, scientometric analysis of the highly cited papers in the Web of Science (WOS) database finds that antioxidant activity is the most widely studied and popular among pharmacological effects of natural polysaccharides. The antioxidant mechanisms of natural polysaccharides mainly contain the regulation of signal transduction pathways, the activation of enzymes, and the scavenging of free radicals. We continuously discuss the antioxidant activities of natural polysaccharides and their derivatives. At the same time, we summarize their applications in the field of pharmaceutics/drug delivery, tissue engineering, and antimicrobial food additives/packaging materials. Overall, this review provides up-to-date information for the further development and application of natural polysaccharides with antioxidant activities.

Fermented Dendrobium officinale polysaccharides protect UVA-induced photoaging of human skin fibroblasts

In this study, Fourier transform infrared spectroscopy (FT‐IR), gel permeation chromatograph‐liquid chromatography (GPC‐LC), and scanning electron microscopy (SEM) were used to analyze the molecular characteristics of fermented Dendrobium officinale polysaccharides (FDOP) by Lactobacillus delbrueckii bulgaricus. The characteristic structural peak of FDOP was more prominent, showing a smaller molecular structure, and its porous structure showed better water solubility. The protective effect of FDOP on the damage of human skin fibroblasts (HSF) caused by ultraviolet (UV) radiation was investigated by evaluating its antioxidative and antiaging indices. The results showed that the antioxidant capacity of HSF was improved, and the breakdown of collagen, elastin, and hyaluronic acid was reduced, thus providing effective protection to the skin tissue. The antioxidative property of FDOP was explored using Nf‐E2‐related factor 2‐small interfering RNA‐3 (Nrf2‐siRNA‐3) (Nrf2‐si3) and qRT‐PCR (quantitative reverse transcription polymerase chain reaction), and the antiaging property of FDOP was explored using Western Blot and qRT‐PCR. The results show that FDOP can up‐regulate signal transduction of the Nrf2/Keap1 (Kelch‐like ECH‐associated protein 1) and transforming growth factor‐β (TGF‐β)/Smads pathways to reduce antioxidative damage and antiaging effects. Therefore, this study provides a theoretical basis for FDOP as a novel functional agent that can be used in the cosmetic industry.

Lycium barbarum polysaccharide protects against osteonecrosis of femoral head via regulating Runx2 expression

BACKGROUND

Osteonecrosis of femoral head (ONFH) is a pathological state caused by lack of blood supply in femoral head. This study aimed to explore the function of Lycium barbarum polysaccharide (LBP), an antioxidant agent extracted from L. barbarum, on ONFH.

METHODS

Osteonecrosis rat model was generated using lipopolysaccharide (LPS) and methylprednisolone followed by examination of body weight, blood glucose, morphology, and BMSC osteoblast differentiation. The effect and underlying mechanism of LBP on the proliferation, apoptosis, and osteoblast differentiation of BMSC were determined with or without LPS or hypoxia treatment using CCK-8. Alizarin Red S staining, flow cytometry, and western blot, respectively.

RESULT

LBP could protect against glucocorticoid-induced ONFH in rats, resulting in improved sparse trabecular bone, empty lacunae and bone cell coagulation. Moreover, LBP promoted the proliferation and osteoblast differentiation of bone mesenchymal-derived stem cells (BMSCs) in a dose-dependent manner. Furthermore, LBP enhanced osteoblast differentiation of BMSCs under hypoxia condition. Mechanistically, we found that LBP treatment enhanced Runx2 and ALP expression in BMSCs. LBP restored the expression of Runx2 and ALP under hypoxia, suggesting that LBP might be involved in regulating Runx2/ALP expression and contributed to osteoblast differentiation. Knockdown of Runx2 significantly inhibited BMSCs proliferation, while LBP treatment did not rescue the osteoblast differentiation ability of BMSCs with Runx2 knockdown.

CONCLUSION

Our findings suggested that LBP protects against ONFH via regulating Runx2 expression, which could be utilized to treat patients suffering ONFH.

Lycium Barbarum polysaccharide protects HaCaT cells from PM2.5-induced apoptosis via inhibiting oxidative stress, ER stress and autophagy

Objectives: Lycium barbarum polysaccharide (LBP) is a natural polysaccharide extracted from Lycium barbarum that has anti-inflammatory, anti-apoptotic and anti-aging effects, and plays a role in the prevention and treatment of various diseases. In this study, we investigated the therapeutic effect of LBP on particulate matter 2.5 (PM2.5)-induced skin damage.

Methods: Cell viability was analyzed by MTT and LDH assays. Apoptosis was analyzed by Annexin V-FITC/PI staining. Oxidative stress/damage were assessed by intracellular ROS levels, MDA content and SOD activity. The intracellular protein expression was analyzed by Western blot. Mitochondrial damage was assayed by mitochondrial membrane potential with JC-1 probe. LC3-GFP adenovirus was transfected into HaCaT cells to analyze intracellular autophagosome levels.

Results: In PM2.5-treated HaCaT cells, LBP pretreatment reduced PM2.5-induced cytotoxicity, ameliorated cell morphology and reduced cell apoptosis. LBP also inhibited the expression levels of GRP78 and CHOP, reduced the conversion of LC3I to LC3II, inhibited Bax protein and activated Bcl-2 protein. Furthermore, LBP inhibited PM2.5-induced mitochondrial autophagy (mitophagy) and mitochondrial damage. PM2.5-induced autophagy was regulated by endoplasmic reticulum (ER) stress.

Conclusion: LBP protects skin cells from PM2.5-induced cytotoxicity by regulating the oxidative stress-ER stress-autophagy-apoptosis signaling axis, revealing that LBP has a great potential for the skin protection.

Comparative Study of Three Raspberry Cultivar (Rubus idaeus L.) Leaves Metabolites: Metabolome Profiling and Antioxidant Activities

Raspberry (Rubus idaeus L.), known as one of the famous healthy fruits an d are consumed fresh or processed products all over the world. The antioxidation activity of raspberry fruits as well as leaves have been widely investigated. To better understand the metabolite accumulation mechanisms and to develop different functional cultivars, we performed a non-targeted metabolomics analysis using LC-MS/MS to investigate the contents of existing components from three raspberry cultivars, Autumn Britten, Autumn Bliss, and Red Autumn leaves, respectively. The results show multiple differentially accumulated metabolites among three cultivars, especially for the lipids (α-linolenic acid and eicosatetraenoic acid), amino acids and their derivatives (L-cysteine, Phenylalanine), flavonoids (Kaempferol 3-O-rhamnoside-7-O-glucoside, Quercetin 3-glucoside), and vitamins (Biotin, Thiamine, Vitamin K2), etc. The in vitro cellular antioxidant activities of three raspberry cultivars leaves ethanol extracts (RLEE) were also characterized. Through comparison the superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and reactive oxygen species (ROS) levels before or after RLEE protection of L929 fibroblast cells upon excessive UVB exposure, we evaluated the antioxidation potentials for all three cultivar RLEEs. It turns out the raspberry Autumn Britten leaf extract holds the greatest potential for protecting the L929 fibroblast cells from UVB induced damage. Our study provides theoretical support for screening of active metabolites from three raspberry cultivars leaves, spanning metabolites’ accumulation to cell damage protection, which could be used to refine bioactivity assessment for different raspberry cultivars suitable for antioxidant products extraction.

Ethnobotanical Survey on Skin Whitening Prescriptions of Traditional Chinese Medicine in Taiwan

The increasing interest and demand for skin whitening products globally, particularly in Asia, have necessitated rapid advances in research on skin whitening products used in traditional Chinese medicine (TCM). Herein, we investigated 74 skin whitening prescriptions sold in TCM pharmacies in Taiwan. Commonly used medicinal materials were defined as those with a relative frequency of citation (RFC) > 0.2 and their characteristics were evaluated. Correlation analysis of commonly used medicinal materials was carried out to identify the core component of the medicinal materials. Of the purchased 74 skin whitening prescriptions, 36 were oral prescriptions, 37 were external prescriptions, and one prescription could be used as an oral or external prescription. After analysis, 90 traditional Chinese medicinal materials were obtained. The Apiaceae (10%; 13%) and Leguminosae (9%; 11%) were the main sources of oral and external medicinal materials, respectively. Oral skin whitening prescriptions were found to be mostly warm (46%) and sweet (53%), while external skin whitening prescriptions included cold (43%) and bitter (29%) medicinal materials. Additionally, mainly tonifying and replenishing effects of the materials were noted. Pharmacological analysis indicated that these medicinal materials may promote wound healing, treat inflammatory skin diseases, or anti-hyperpigmentation. According to the Spearman correlation analysis on interactions among medicinal materials with an RFC > 0.2 in the oral skin whitening prescriptions, Paeonia lactiflora Pall. (white) and Atractylodes macrocephala Koidz. showed the highest correlation (confidence score = 0.93), followed by Ziziphus jujuba Mill. (red) and Astragalus propinquus Schischkin (confidence score = 0.91). Seven medicinal materials in external skin whitening prescriptions with an RFC > 0.2, were classified as Taiwan qī bái sàn (an herbal preparation), including Angelica dahurica (Hoffm.) Benth. & Hook. f. ex Franch. & Sav., Wolfiporia extensa (Peck) Ginns, Bletilla striata (Thunb.) Rchb. f., Atractylodes macrocephala Koidz., Ampelopsis japonica (Thunb.) Makino, Paeonia lactiflora Pall. (white), and Bombyx mori Linnaeus. Skin whitening prescriptions included multiple traditional Chinese medicinal materials. Despite the long history of use, there is a lack of studies concerning skin whitening products, possibly due to the complex composition of traditional Chinese medicine. Further studies are required to assess the efficacy and safety of these traditional Chinese medicinal materials for inclusion in effective, safe, and functional pharmacological products.

Lycium barbarum polysaccharide protects rats and cardiomyocytes against ischemia/reperfusion injury via Nrf2 activation through autophagy inhibition

The irreversible loss of cardiomyocytes is mainly the result of ischemic/reperfusion (I/R) myocardial injury, leading to persistent heart dysfunction and heart failure. It has been reported that Lycium barbarum polysaccharide (LBP) has protective effects on cardiomyocytes, but the specific mechanism is still not completely understood. The present study examined the protective role of LBP in myocardial I/R injury. Rats were subjected to myocardial I/R injury and LBP treatment. Moreover, rat myocardial H9C2 cells exposed to hypoxia/reoxygenation (H/R) were used to simulate cardiac injury during myocardial I/R process and were exposed to LBP, rapamycin (an autophagy activator) or nuclear factor-erythroid factor 2-related factor 2 (Nrf2) transfection. Morphological examination, histopathological examination and echocardiography were used to determine the cardiac injury after I/R injury. Cell viability and apoptosis were determined via MTT and flow cytometry assays, respectively. The levels of lactate dehydrogenase (LDH), creatine kinase (CK), cardiac troponin T (cTnT), IL-1β, IL-6, TNF-α, malondialdehyde (MDA) and superoxidase dismutase (SOD) in rat serum, hearts and/or cells were assessed using ELISAs. The expression levels of Beclin 1, LC3II/LC3I, P62 and Nrf2 were analyzed via reverse transcription-quantitative PCR and western blotting. The results demonstrated that LBP improved heart function and repaired cardiomyocyte damage in I/R model rats, as well as reduced the production of cTnT, CK, LDH, IL-1β, IL-6 and TNF-α. The in vitro study results indicated that LBP increased cell viability, the apoptosis rate, and the levels of SOD and P62, as well as reduced the levels of LDH, CK, IL-1β, IL-6, TNF-α, MDA, Beclin 1 and LC3-II/LC3-I in H/R-injured H9C2 cells. Moreover, LBP promoted Nrf2 nuclear translocation, but decreased Nrf2 expression in the cytoplasm. Rapamycin exacerbated the aforementioned effects in H/R injured H9C2 cells, and partially reversed LBP-induced effects. Overexpressing Nrf2 counteracted I/R-induced effects and partially resisted rapamycin-induced effects. These findings demonstrated that LBP exhibited a cardiac protective effect on the ischemic myocardium of rats after reperfusion and attenuated myocardial I/R injury via autophagy inhibition-induced Nrf2 activation.

Lycium barbarum polysaccharides in ageing and its potential use for prevention and treatment of osteoarthritis: a systematic review

BACKGROUND

Lycium barbarum polysaccharide (LBP), the most abundant functional component of wolfberry, is considered a potent antioxidant and an anti-ageing substance. This review aims to outline the hallmarks of ageing in the pathogenesis of osteoarthritis (OA), followed by the current understanding of the senolytic effect of LBP and its potential use in the prevention and treatment of OA. This will be discussed through the lens of molecular biology and herbal medicine.

METHODS

A literature search was performed from inception to March 2020 using following keywords: "Lycium barbarum polysaccharide", "DNA damage", antioxidant, anti-apoptosis, anti-inflammation, anti-ageing, osteoarthritis, chondrocytes, fibroblasts, osteoblasts, osteoclasts, and "bone mesenchymal stem cell". The initial search yielded 2287 papers, from which 35 studies were selected for final analysis after screening for topic relevancy by the authors.

RESULTS

In literature different in vitro and in vivo ageing models are used to demonstrate LBP's ability to reduce oxidative stress, restore mitochondrial function, mitigate DNA damage, and prevent cellular senescence. All the evidence hints that LBP theoretically attenuates senescent cell accumulation and suppresses the senescence-associated secretory phenotype as observed by the reduction in pro-inflammatory cytokines, like interleukin-1beta, and matrix-degrading enzymes, such as MMP-1 and MMP-13. However, there remains a lack of evidence on the disease-modifying effect of LBP in OA, although its chondroprotective, osteoprotective and anti-inflammatory effects were reported.

CONCLUSION

Our findings strongly support further investigations into the senolytic effect of LBP in the context of age-related OA.

Polysaccharide-rich hydrogel formulation combined with photobiomodulation repairs UV-induced photodamage in mice skin

Prolonged skin exposure to ultraviolet radiation (UVR) induces premature aging in both the epidermis and the dermis. Chronic exposure to UVR induces the activation of mitogen-activated protein kinase (MAPK) signaling pathway, activating c-Jun, c-Fos expression, and transcription factor of AP-1 activating protein. AP-1 activation results in the positive induction of matrix metalloproteinase (MMP) synthesis, which degrade skin collagen fibers. Polysaccharides from the fruit of Lycium barbarum (LBP fraction) have a range of activities and have been demonstrate to repair the photodamage. In different approaches, laser application aims to recover the aged skin without destroying the epidermis, promoting a modulation, called photobiomodulation (PBM), which leads to protein synthesis and cell proliferation, favoring tissue repair. Here we developed a topical hydrogel formulation from a polysaccharide-rich fraction of Lycium barbarum fruits (LBP). This formulation was associated with PBM (red laser) to evaluate whether the isolated and combined treatments would reduce the UVR-mediated photodamage in mice skin. Hairless mice were photoaged for 6 weeks and then treated singly or in combination with LBP and PBM. Histological, immunohistochemistry, and immunofluorescence analyses were used to investigate the levels of c-Fos, c-Jun, MMP-1, -2, and -9, collagen I, III, and FGF2. The combined regimen inhibited UVR-induced skin thickening, decreased the expression of c-Fos and c-Jun, as well as MMP-1, -2, and -9 and concomitantly increased the levels of collagen I, III, and FGF2. The PBM in combination with LBP treatment is a promising strategy for the repair of photodamaged skin, presenting potential clinical application in skin rejuvenation.

Asiaticoside inhibits TGF-β1-induced mesothelial-mesenchymal transition and oxidative stress via the Nrf2/HO-1 signaling pathway in the human peritoneal mesothelial cell line HMrSV5

Background

Peritoneal fibrosis (PF) is a frequent complication caused by peritoneal dialysis (PD). Peritoneal mesothelial cells (PMCs), the first barrier of the peritoneum, play an important role in maintaining structure and function in the peritoneum during PD. Mesothelial-mesenchymal transition (MMT) and oxidative stress of PMCs are two key processes of PF.

Purpose

To elucidate the efficacy and possible mechanism of asiaticoside inhibition of MMT and ROS generation in TGF-β1-induced PF in human peritoneal mesothelial cells (HPMCs).

Methods

MMT and ROS generation of HPMCs were induced by TGF-β1. To explain the anti-MMT and antioxidant role of asiaticoside, varied doses of asiaticoside, oxygen radical scavenger (NAC), TGF-β receptor kinase inhibitor (LY2109761) and Nrf2 inhibitor (ML385) were used separately. Immunoblots were used to detect the expression of signaling associated proteins. DCFH-DA was used to detect the generation of ROS. Transwell migration assay and wound healing assay were used to verify the capacity of asiaticoside to inhibit MMT. Immunofluorescence assay was performed to observe the subcellular translocation of Nrf2 and expression of HO-1.

Results

Asiaticoside inhibited TGF-β1-induced MMT and suppressed Smad signaling in a dose-dependent manner. Migration and invasion activities of HPMCs were decreased by asiaticoside. Asiaticoside decreased TGF-β1-induced ROS, especially in a high dose (150 μM) for 6 h. Furthermore, ML385 partly abolished the inhibitory effect of asiaticoside on MMT, ROS and p-Smad2/3.

Conclusions

Asiaticoside inhibited the TGF-β1-induced MMT and ROS via Nrf2 activation, thus protecting the peritoneal membrane and preventing PF.

Nrf2 Overexpression for the Protective Effect of Skin-Derived Precursors against UV-Induced Damage: Evidence from a Three-Dimensional Skin Model

Background

Skin photodamage is associated with ultraviolet- (UV-) induced reactive oxygen species (ROS) overproduction and nuclear factor erythroid 2-related factor 2 (Nrf2) inactivation. In our previous study, skin-derived precursors (SKPs) were shown to ameliorate a UV-induced damage in mice, probably through Nrf2 activation and ROS scavenging.

Objective

To clarify the mechanism underlying the photoprotective effect of SKPs against UV-induced damage in a three-dimensional (3D) skin model.

Methods

The Nrf2 gene in SKPs was modified using lentiviral infection, and 3D skin models were reconstructed with keratinocytes and fibroblasts on the basis of type I collagen. Subsequently, these models were divided into the following six groups: normal, model, overexpressed, control, silenced, and negative control groups. Prior to irradiation, respective SKPs were injected into the last four groups. Next, all groups except the normal group were exposed to UVA+UVB. Lastly, the pathological and molecular-biological techniques were employed to determine the parameters. Additionally, LY294002, a PI3K inhibitor, was used to investigate the roles of PI3K/Akt and Nrf2/hemeoxygenase-1 (HO-1) in SKP photoprotection.

Results

Normal 3D skin models appeared as milky-white analogs with a clear, well-arranged histological structure. After the skin was exposed to irradiation, it exhibited cell swelling and a disorganized structure and developed nuclear condensation with numerous apoptotic cells. The expressions of cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins remarkably decreased, which were accompanied by increased oxidative stress and decreased antioxidants (P < 0.05). However, these phenomena were reversed by nrf2-overexpressing SKPs. The 3D skin in the overexpressed group showed mild swelling, neatly arranged cells, and few apoptotic cells. Cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins were highly expressed, and the oxidative biomarkers were remarkably ameliorated (P < 0.05). Nevertheless, the expression of these proteins decreased after LY294002 pretreatment regardless of SKP treatment or not. Meanwhile, there were increases in both UV-induced apoptotic cells and ROS level accompanied with SOD and GPX decrease in the presence of LY294002.

Conclusions

Evidence from the 3D skin model demonstrates that the protection of SKPs against UV-mediated damage is primarily via the PI3K/Akt-mediated activation of the Nrf2/HO-1 pathway, indicating that SKPs may be a promising candidate for the treatment of photodermatoses.

Extraction, Structural Characterization, and Biological Functions of Lycium Barbarum Polysaccharides: A Review

Lycium barbarum polysaccharides (LBPs), as bioactive compounds extracted from L. barbarum L. fruit, have been widely explored for their potential health properties. The extraction and structural characterization methods of LBPs were reviewed to accurately understand the extraction method and structural and biological functions of LBPs. An overview of the biological functions of LBPs, such as antioxidant function, antitumor activity, neuroprotective effects, immune regulating function, and other functions, were summarized. This review provides an overview of LBPs and a theoretical basis for further studying and extending the applications of LBPs in the fields of medicine and food.

ATRA protects skin fibroblasts against UV‑induced oxidative damage through inhibition of E3 ligase Hrd1

All-trans retinoic acid (ATRA) can protect fibroblasts against ultraviolet (UV)-induced oxidative damage, however, its underlying molecular mechanism is still unclear. The present study aimed to investigate the role of 3-hydroxy-3-methylglutaryl reductase degradation (Hrd1) in the protective effect of ATRA on human skin fibroblasts exposed to UV. The expression of Hrd1 in human or mice skin was assessed by immunohistochemistry (IHC) staining and western blot analysis. Hrd1 siRNA (si-Hrd1) and Hrd1 recombinant adenoviruses (Ad-Hrd1) were used to downregulate and upregulate Hrd1 expression in fibroblasts, respectively. The interaction between Hrd1 and NF-E2-related factor 2 (Nrf2) was assessed by co-immunoprecipitation (co-IP) and immunofluorescence analysis. The results revealed that Hrd1 expression was increased but Nrf2 expression was decreased in UV-exposed human skin fibroblasts. In addition, ATRA could reverse the increase of Hrd1 expression induced by UV radiation in vivo and in vitro. ATRA or knockdown of Hrd1 could increase Nrf2 expression in fibroblasts exposed to UV radiation, and Hrd1 could directly interact with Nrf2 in skin fibroblasts. Notably, overexpression of Hrd1 abolished the protective effect of ATRA on the UV-induced decrease of Nrf2 expression, the production of reactive oxygen species (ROS) and the decrease of cell viability. In conclusion, the present data demonstrated that ATRA protected skin fibroblasts against UV-induced oxidative damage through inhibition of E3 ligase Hrd1.

Comparison of Functional Components and Antioxidant Activity of Lycium barbarum L. Fruits from Different Regions in China

The fruit of Lycium barbarum L. (FLB) has been used as medicines and functional foods for more than 2000 years in East Asia. In this study, carotenoid, phenolic, flavonoid, and polysaccharide contents as well as the antioxidant activities of FLB from 13 different regions in China from a total of 78 samples were analyzed. The results showed that total carotenoid contents ranged from 12.93 to 25.35 mg β-carotene equivalents/g DW. Zeaxanthin dipalmitate was the predominant carotenoid (4.260–10.07 mg/g DW) in FLB. The total phenolic, total flavonoid, and total polysaccharide contents ranged from 6.899 to 8.253 mg gallic acid equivalents/g DW, 3.177 to 6.144 mg rutin equivalents/g DW, and 23.62 to 42.45 mg/g DW, respectively. Rutin content ranged from 0.1812 to 0.4391 mg/g DW, and ferulic acid content ranged from 0.0994 to 0.1726 mg/g DW. All of these FLB could be divided into two clusters with PCA analysis, and both individual carotenoids and total carotenoid contents could be used as markers for regional characterization. The phenolic components were the main substance for the antioxidant activity of FLB. Considering the functional component and antioxidant activities, FLB produced in Guyuan of Ningxia was the closest to Daodi herbs (Zhongwei of Ningxia), which is commercially available high quality FLB. The results of this study could provide guidance for comprehensive applications of FLB production in different regions.

Lycium barbarum polysaccharide reduces hyperoxic acute lung injury in mice through Nrf2 pathway

INTRODUCTION

The disruption of the balance between antioxidants and oxidants plays a vital role in the pathogenesis of acute lung injury (ALI). Evidence has shown that Lycium barbarum polysaccharide (LBP) has antioxidant feature. We examined the efficacy and mechanisms of LBP on hyperoxia-induced acute lung injury (ALI) in the present study.

MATERIALS AND METHODS

C57BL/6 wild-type (WT) mice and nuclear factor erythroid 2-related factor 2 (Nrf2)-deficient (Nrf2^-/-) mice were used in the present study. LBP was fed by gavages once daily for 1 week. Then, the mice were exposed to hyperoxia or room air for 72 h. Additional dosage of LBP was given per 24 h.

RESULTS

Reactive oxygen species production was increased in WT mice exposed to hyperoxia. Inflammatory cytokines including interleukin (IL)-1β as well as IL-6, and inflammatory cells were increased infiltration in the lung after 3 days hyperoxia exposure. Hyperoxia exposure also induced pulmonary edema and histopathological changes. These hyperoxia-induced changes were improved in LBP treated group. Moreover, elevated activities of heme oxygenase-1 and glutathione peroxidase and enhanced activation of Nrf2 were observed in mice treated with LBP. However, the benefit of LBP on hyperoxic ALI was abolished in Nrf2^-/- mice. Moreover, our cell study showed that the LBP-induced activation of Nrf2 was dampened in pulmonary microvascular endothelial cells when the AMPK signal was inhibited by siRNA.

CONCLUSIONS

LBP improves hyperoxic ALI via Nrf2-dependent manner. The LBP-induced activation of Nrf2 is mediated, at least in part, by AMPK pathway.