Plasma-Induced Oxidation Products of (–)-Epigallocatechin Gallate with Digestive Enzymes Inhibitory Effects

(−)-Epigallocatechin gallate (EGCG), the chief dietary constituent in green tea (Camellia sinensis), is relatively unstable under oxidative conditions. This study evaluated the use of non-thermal dielectric barrier discharge (DBD) plasma to improve the anti-digestive enzyme capacities of EGCG oxidation products. Pure EGCG was dissolved in an aqueous solution and irradiated with DBD plasma for 20, 40, and 60 min. The reactant, irradiated for 60 min, exhibited improved inhibitory properties against α-glucosidase and α-amylase compared with the parent EGCG. The chemical structures of these oxidation products 1–3 from the EGCG, irradiated with the plasma for 60 min, were characterized using spectroscopic methods. Among the oxidation products, EGCG quinone dimer A (1) showed the most potent inhibitory effects toward α-glucosidase and α-amylase with IC₅₀ values of 15.9 ± 0.3 and 18.7 ± 0.3 μM, respectively. These values were significantly higher than that of the positive control, acarbose. Compound 1, which was the most active, was the most abundant in the plasma-irradiated reactant for 60 min according to quantitative high-performance liquid chromatography analysis. These results suggest that the increased biological capacity of EGCG can be attributed to the structural changes to EGCG in H₂O, induced by cold plasma irradiation.     

Alterations in β-Cell Sphingolipid Profile Associated with ER Stress and iPLA2β: Another Contributor to β-Cell Apoptosis in Type 1 Diabetes

Type 1 diabetes (T1D) development, in part, is due to ER stress-induced β-cell apoptosis. Activation of the Ca²⁺-independent phospholipase A₂ beta (iPLA₂β) leads to the generation of pro-inflammatory eicosanoids, which contribute to β-cell death and T1D. ER stress induces iPLA₂β-mediated generation of pro-apoptotic ceramides via neutral sphingomyelinase (NSMase). To gain a better understanding of the impact of iPLA₂β on sphingolipids (SLs), we characterized their profile in β-cells undergoing ER stress. ESI/MS/MS analyses followed by ANOVA/Student’s t-test were used to assess differences in sphingolipids molecular species in Vector (V) control and iPLA₂β-overexpressing (OE) INS-1 and Akita (AK, spontaneous model of ER stress) and WT-littermate (AK-WT) β-cells. As expected, iPLA₂β induction was greater in the OE and AK cells in comparison with V and WT cells. We report here that ER stress led to elevations in pro-apoptotic and decreases in pro-survival sphingolipids and that the inactivation of iPLA₂β restores the sphingolipid species toward those that promote cell survival. In view of our recent finding that the SL profile in macrophages—the initiators of autoimmune responses leading to T1D—is not significantly altered during T1D development, we posit that the iPLA₂β-mediated shift in the β-cell sphingolipid profile is an important contributor to β-cell death associated with T1D.     

Synthesis,Stability, and Antidiabetic Activity Evaluation of (−)-Epigallocatechin Gallate (EGCG) Palmitate Derived from Natural Tea Polyphenols

This work describes a novel approach for the synthesis of (−)-epigallocatechin gallate (EGCG) palmitate by a chemical-synthesis method, where the elevated stability of the EGCG derivative is achieved. Various parameters affecting the acylation process, such as the base, solvent, as well as the molar ratio of palmitoyl chloride, have been studied to optimize the acylation procedure. The optimized reaction condition was set as follows: EGCG/palmitoyl chloride/sodium acetate was under a molar ratio of 1:2:2, with acetone as the solvent, and the reaction temperature was 40 °C. Under the optimized condition, the yield reached 90.6%. The EGCG palmitate (PEGCG) was isolated and identified as 4′-O-palmitoyl EGCG. Moreover, the stability of PEGCG under different conditions was proved significantly superior to EGCG. Finally, PEGCG showed better inhibition towards α-amylase and α-glucosidase, which was 4.5 and 52 times of EGCG, respectively. Molecular docking simulations confirmed the in vitro assay results. This study set a novel and practical synthetic approach for the derivatization of EGCG, and suggest that PEGCG may act as an antidiabetic agent.     

Phenolic Compounds from Mori Cortex Ameliorate Sodium Oleate-Induced Epithelial–Mesenchymal Transition and Fibrosis in NRK-52e Cells through CD36

Lipid deposition in the kidney can cause serious damage to the kidney, and there is an obvious epithelial–mesenchymal transition (EMT) and fibrosis in the late stage. To investigate the interventional effects and mechanisms of phenolic compounds from Mori Cortex on the EMT and fibrosis induced by sodium oleate-induced lipid deposition in renal tubular epithelial cells (NRK-52e cells), and the role played by CD36 in the adjustment process, NRK-52e cells induced by 200 μmol/L sodium oleate were given 10 μmoL/L moracin-P-2″-O-β-d-glucopyranoside (Y-1), moracin-P-3′-O-β-d-glucopyranoside (Y-2), moracin-P-3′-O-α-l-arabinopyranoside (Y-3), and moracin-P-3′-O-[β-glucopyranoside-(1→2)arabinopyranoside] (Y-4), and Oil Red O staining was used to detect lipid deposition. A Western blot was used to detect lipid deposition-related protein CD36, inflammation-related protein (p-NF-κB-P65, NF-κB-P65, IL-1β), oxidative stress-related protein (NOX1, Nrf2, Keap1), EMT-related proteins (CD31, α-SMA), and fibrosis-related proteins (TGF-β, ZEB1, Snail1). A qRT-PCR test detected inflammation, EMT, and fibrosis-related gene mRNA levels. The TNF-α levels were detected by ELISA, and the colorimetric method was used to detects SOD and MDA levels. The ROS was measured by flow cytometry. A high-content imaging analysis system was applied to observe EMT and fibrosis-related proteins. At the same time, the experiment silenced CD36 and compared the difference between before and after drug treatment, then used molecular docking technology to predict the potential binding site of the active compounds with CD36. The research results show that sodium oleate can induce lipid deposition, inflammation, oxidative stress, and fibrosis in NRK-52e cells. Y-1 and Y-2 could significantly ameliorate the damage caused by sodium oleate, and Y-2 had a better ameliorating effect, while there was no significant change in Y-3 or Y-4. The amelioration effect of Y-1 and Y-2 disappeared after silencing CD36. Molecular docking technology showed that the Y-1 and Y-2 had hydrogen bonds to CD36 and that, compared with Y-1, Y-2 requires less binding energy. In summary, moracin-P-2″-O-β-d-glucopyranoside and moracin-P-3′-O-β-d-glucopyranoside from Mori Cortex ameliorated lipid deposition, EMT, and fibrosis induced by sodium oleate in NRK-52e cells through CD36.     

The Effect of α-Tocopherol on the Reduction of Inflammatory Processes and the Negative Effect of Acrylamide

Our research aimed to show acrylamide’s influence on inflammatory processes, the oxidative stress it causes in the cholinergic system, and the possibility of reducing inflammation via supplementation with α-tocopherol. For this purpose, an in ovo model was used where the embryos were exposed to acrylamide, α-tocopherol and a cocktail of these substances. After 48 h of exposure, we collected brain samples and performed biochemical assays to examine the effect of the chosen substances on oxidative stress (malondialdehyde-MDA and reduced glutathione-GSH) and acetylcholinesterase activity (AChE). The results showed that acrylamide decreased AChE activity in the examined brain samples by about 25% in comparison to the control group, and this effect was decreased by administering α-tocopherol. The concentration of malondialdehyde significantly increased in the group given acrylamide, while, in the group with α-tocopherol, the observed concentration was lower in comparison to the control group. Moreover, a decrease in glutathione concentration was observed after the administration of acrylamide; however, the protective effect of α-tocopherol was only slightly visible in this case. In conclusion, α-tocopherol minimizes the harmful effects of acrylamide on AchE, and it can minimize the concentration of MDA.     

Polyphenols isolated from Broussonetia kazinoki prevent cytokine-induced β-cell damage and the development of type 1 diabetes

The axis of nuclear factor κB (NF-κB)-inducible NO synthase (iNOS)-nitric oxide plays a key role in cytokine- and streptozotocin-mediated pancreatic β-cell damage. In this study, we investigated the effects of kazinol C and isokazinol D isolated from Broussonetia kazinoki on the β-cell viability and function. RINm5F cells and primary islets were used for in vitro and ex vivo cytokine toxicity experiments, respectively. For type 1 diabetes induction, mice were injected with multiple low-dose streptozotocin (MLDS). Cytokine-induced toxicity was completely abolished in both RINm5F cells and islets that were pretreated with either kazinol C or isokazinol D. Both kazinols inhibited the NF-κB signaling pathway, thereby inhibiting cytokine-mediated iNOS induction, nitric oxide production, apoptotic cell death and defects in insulin secretion. Moreover, the occurrence of diabetes in MLDS-treated mice was efficiently attenuated in kazinol-pretreated mice. Immunohistochemical analysis revealed that the numbers of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive apoptotic cells and nuclear p65-positive cells were significantly decreased in kazinol-pretreated mice. Our results suggest that kazinol C and isokazinol D block the NF-κB pathway, thus reducing the extent of β-cell damage. Therefore, kazinol C and isokazinol D may have therapeutic value in delaying pancreatic β-cell damage in type 1 diabetes.     

Sulfuretin protects against cytokine-induced ��-cell damage and prevents streptozotocin-induced diabetes

NF-κB activation has been implicated as a key signaling mechanism for pancreatic β-cell damage. Sulfuretin is one of the main flavonoids produced by Rhus verniciflua, which is reported to inhibit the inflammatory response by suppressing the NF-κB pathway. Therefore, we isolated sulfuretin from Rhus verniciflua and evaluated if sulfuretin could inhibit cytokine- or streptozotocin-induced β-cell damage. Rat insulinoma RINm5F cells and isolated rat islets were treated with IL-1β and IFN-γ to induce cytotoxicity. Incubation of cells and islets with sulfuretin resulted in a significant reduction of cytokine-induced NF-κB activation and its downstream events, iNOS expression, and nitric oxide production. The cytotoxic effects of cytokines were completely abolished when cells or islets were pretreated with sulfuretin. The protective effect of sulfuretin was further demonstrated by normal insulin secretion of cytokine-treated islets in response to glucose. Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by immunohistochemical staining of islets. However, the diabetogenic effects of streptozotocin were completely prevented when mice were pretreated with sulfuretin. The anti-diabetogenic effects of sulfuretin were also mediated by suppression of NF-κB activation. Collectively, these results indicate that sulfuretin may have therapeutic value in preventing β-cell damage.     

Antibacterial Mechanisms of Zinc Oxide Nanoparticle against Bacterial Food Pathogens Resistant to Beta-Lactam Antibiotics

The increase in β-lactam-resistant Gram-negative bacteria is a severe recurrent problem in the food industry for both producers and consumers. The development of nanotechnology and nanomaterial applications has transformed many features in food science. The antibacterial activity of zinc oxide nanoparticles (ZnO NPs) and their mechanism of action on β-lactam-resistant Gram-negative food pathogens, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Klebsiella pneumoniae, and Proteus mirabilis, are investigated in the present paper. The study results demonstrate that ZnO NPs possesses broad-spectrum action against these β-lactamase-producing strains. The minimal inhibitory and minimal bactericidal concentrations vary from 0.04 to 0.08 and 0.12 to 0.24 mg/mL, respectively. The ZnO NPs elevate the level of reactive oxygen species (ROS) and malondialdehyde in the bacterial cells as membrane lipid peroxidation. It has been confirmed from the transmission electron microscopy image of the treated bacterial cells that ZnO NPs diminish the permeable membrane, denature the intracellular proteins, cause DNA damage, and cause membrane leakage. Based on these findings, the action of ZnO NPs has been attributed to the fact that broad-spectrum antibacterial action against β-lactam-resistant Gram-negative food pathogens is mediated by Zn²⁺ ion-induced oxidative stress, actions via lipid peroxidation and membrane damage, subsequently resulting in depletion, leading to β-lactamase enzyme inhibition, intracellular protein inactivation, DNA damage, and eventually cell death. Based on the findings of the present study, ZnO NPs can be recommended as potent broad-spectrum antibacterial agents against β-lactam-resistant Gram-negative pathogenic strains.     

Carnosic Acid Protects INS-1 β-Cells against Streptozotocin-Induced Damage by Inhibiting Apoptosis and Improving Insulin Secretion and Glucose Uptake

Carnosic acid (CA), a natural polyphenolic diterpene derived from Rosmarinus officinalis, has been proven to possess a broad spectrum of medicinal properties. Nevertheless, no studies on its impact on pancreatic β-cells have been conducted to date. Herein, clonal rat INS-1 (832/13) cells were pretreated with CA for 24 h and then incubated with streptozotocin (STZ) for 3 h. Several functional experiments were performed to determine the effect of CA on STZ-induced pancreatic β-cell damage, including cell viability assay, apoptosis analysis, and measurement of the level of insulin secretion, glucose uptake, malondialdehyde (MDA), reactive oxygen species (ROS), and proteins expression. STZ treatment decreased cell survival, insulin secretion, glucose uptake, and increased apoptosis, MDA, and ROS production in INS-1 cells. Furthermore, protein expression/phosphorylation analysis showed significant down-regulation in insulin, PDX-1, PI3K, AKT/p-AKT, and Bcl₂. On the other hand, expression of BAX and BAD and cleaved PARP were significantly increased. Interestingly, preincubation with CA reversed the adverse impact of STZ at the cellular and protein expression levels. In conclusion, the data indicate that CA protects β-cells against STZ-induced damage, presumably through its modulatory effect on the different pathways, including the Pi3K/AKT/PDX-1/insulin pathway and mitochondria-mediated apoptosis.     

Phospholipase D activates HIF-1-VEGF pathway via phosphatidic acid

Growth factor-stimulated phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC), generating phosphatidic acid (PA) which may act as a second messenger during cell proliferation and survival. Therefore, PLD is believed to play an important role in tumorigenesis. In this study, a potential mechanism for PLD-mediated tumorigenesis was explored. Ectopic expression of PLD1 or PLD2 in human glioma U87 cells increased the expression of hypoxia-inducible factor-1α (HIF-1α) protein. PLD-induced HIF-1 activation led to the secretion of vascular endothelial growth factor (VEGF), a HIF-1 target gene involved in tumorigenesis. PLD induction of HIF-1α was significantly attenuated by 1-butanol which blocks PA production by PLD, and PA per se was able to elevate HIF-1α protein level. Inhibition of mTOR, a PA-responsive kinase, reduced the levels of HIF-1α and VEGF in PLD-overexpressed cells. Epidermal growth factor activated PLD and increased the levels of HIF-1α and VEGF in U87 cells. A specific PLD inhibitor abolished expression of HIF-1α and secretion of VEGF. PLD may utilize HIF-1-VEGF pathway for PLD-mediated tumor cell proliferation and survival.     

Antioxidant and Anti-Inflammatory Potential of Polyphenols Contained in Mediterranean Diet in Obesity: Molecular Mechanisms

Nutrition transition can be defined as shifts in food habits, and it is characterized by high-fat (chiefly saturated animal fat), hypercaloric and salty food consumption at the expense of dietary fibers, minerals and vitamins. Western dietary patterns serve as a model for studying the impact of nutrition transition on civilization diseases, such as obesity, which is commonly associated with oxidative stress and inflammation. In fact, reactive oxygen species (ROS) overproduction can be associated with nuclear factor-κB (NF-κB)-mediated inflammation in obesity. NF-κB regulates gene expression of several oxidant-responsive adipokines including tumor necrosis factor-α (TNF-α). Moreover, AMP-activated protein kinase (AMPK), which plays a pivotal role in energy homeostasis and in modulation of metabolic inflammation, can be downregulated by IκB kinase (IKK)-dependent TNF-α activation. On the other hand, adherence to a Mediterranean-style diet is highly encouraged because of its healthy dietary pattern, which includes antioxidant nutraceuticals such as polyphenols. Indeed, hydroxycinnamic derivatives, quercetin, resveratrol, oleuropein and hydroxytyrosol, which are well known for their antioxidant and anti-inflammatory activities, exert anti-obesity proprieties. In this review, we highlight the impact of the most common polyphenols from Mediterranean foods on molecular mechanisms that mediate obesity-related oxidative stress and inflammation. Hence, we discuss the effects of these polyphenols on a number of signaling pathways. We note that Mediterranean diet (MedDiet) dietary polyphenols can de-regulate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and NF-κB-mediated oxidative stress, and metabolic inflammation. MedDiet polyphenols are also effective in upregulating downstream effectors of several proteins, chiefly AMPK.     

5-Bromo-3,4-dihydroxybenzaldehyde Promotes Hair Growth through Activation of Wnt/β-Catenin and Autophagy Pathways and Inhibition of TGF-β Pathways in Dermal Papilla Cells

Various studies addressing the increasing problem of hair loss, using natural products with few side effects, have been conducted. 5-bromo-3,4-dihydroxybenzaldehyde (BDB) exhibited anti-inflammatory effects in mouse models of atopic dermatitis and inhibited UVB-induced oxidative stress in keratinocytes. Here, we investigated its stimulating effect and the underlying mechanism of action on hair growth using rat vibrissa follicles and dermal papilla cells (DPCs), required for the regulation of hair cycle and length. BDB increased the length of hair fibers in rat vibrissa follicles and the proliferation of DPCs, along with causing changes in the levels of cell cycle-related proteins. We investigated whether BDB could trigger anagen-activating signaling pathways, such as the Wnt/β-catenin pathway and autophagy in DPCs. BDB induces activation of the Wnt/β-catenin pathway through the phosphorylation of GSG3β and β-catenin. BDB increased the levels of autophagic vacuoles and autophagy regulatory proteins Atg7, Atg5, Atg16L, and LC3B. We also investigated whether BDB inhibits the TGF-β pathway, which promotes transition to the catagen phase. BDB inhibited the phosphorylation of Smad2 induced by TGF-β1. Thus, BDB can promote hair growth by modulating anagen signaling by activating Wnt/β-catenin and autophagy pathways and inhibiting the TGF-β pathway in DPCs.     

Crosslinked Hyaluronic Acid with Liposomes and Crocin Confers Cytoprotection in an Experimental Model of Dry Eye

Dry eye disease (DED) is a multifactorial condition caused by tear deficiency and accompanied by ocular surface damage. Recent data support a key role of oxidative and inflammatory processes in the pathogenesis of DED. Hyaluronic acid (HA) is widely used in artificial tears to treat DED by improving ocular hydration and reducing surface friction. Crocin (Cr), the main constituent of saffron, is a renowned compound that exhibits potent antioxidant and anti-inflammatory effects. The present study was undertaken to assess the viscosity and muco-adhesiveness of a photoactivated formulation with crosslinked HA (cHA), Cr, and liposomes (cHA-Cr-L). Our aim was also to evaluate whether cHA-Cr-L may exert cytoprotective effects against oxidative and inflammatory processes in human corneal epithelial cells (HCECs). Viscosity was measured using a rotational rheometer, and then the muco-adhesiveness was evaluated. Under hyperosmolarity (450 mOsm), the HCECs were treated with cHA-Cr-L. Interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) were quantified by quantitative real-time polymerase chain reaction (RT-qPCR). The levels of reactive oxygen species (ROS) were measured using the DCF assay. The combined action of cHA-Cr-L produced a higher viscosity and muco-adhesiveness compared to the control. The anti-inflammatory effect of cHA-Cr-L was achieved through a significant reduction of IL-1β and TNFα (p < 0.001). The results also showed that cHA-Cr-L reduces ROS production under conditions of hyperosmolarity (p < 0.001). We conclude that cHA-Cr-L has potential as a therapeutic agent in DED, which should be further investigated.     

Genetically-targeted photorelease of endocannabinoids enables optical control of GPR55 in pancreatic β-cells

Fatty acid amides (FAAs) are a family of second-messenger lipids that target cannabinoid receptors, and are known mediators of glucose-stimulated insulin secretion from pancreatic β-cells. Due to the diversity observed in FAA structure and pharmacology, coupled with the expression of at least 3 different cannabinoid G protein-coupled receptors in primary and model β-cells, our understanding of their role is limited by our inability to control their actions in time and space. To investigate the mechanisms by which FAAs regulate β-cell excitability, we developed the Optically-Cleavable Targeted (OCT)-ligand approach, which combines the spatial resolution of self-labeling protein (SNAP-) tags with the temporal control of photocaged ligands. By linking a photocaged FAA to an o-benzylguanine (BG) motif, FAA signalling can be directed towards genetically-defined cellular membranes. We designed a probe to release palmitoylethanolamide (PEA), a GPR55 agonist known to stimulate glucose-stimulated insulin secretion (GSIS). When applied to β-cells, OCT-PEA revealed that plasma membrane GPR55 stimulates β-cell Ca²⁺ activity via phospholipase C. Moving forward, the OCT-ligand approach can be translated to other ligands and receptors, and will open up new experimental possibilities in targeted pharmacology.

Optically-cleavable targeted ligands unite photocaged chemistry with genetic targeting to induce cell activity at defined membranes. OCT-PEA uncaging stiumlates β-cell activity via cell surface GPR55.     

Eriodictyol and Homoeriodictyol Improve Memory Impairment in Aβ25–35-Induced Mice by Inhibiting the NLRP3 Inflammasome

(1) Alzheimer’s disease (AD) is a neurodegenerative disorder, and it is now widely accepted that neuroinflammation plays a key role in its pathogenesis. Eriodictyol (Eri) and homoeriodictyol (Hom), dihydroflavonoids extracted from a variety of plants, have been confirmed to display a relationship with neuroprotection. (2) Methods: An AD mouse model was constructed by intracerebroventricular (ICV) injection of the Aβ_25–35 peptide, and Eri and Hom were administered orally for 4 weeks. UPLC-MS/MS was used to determine whether Eri and Hom cross the blood–brain barrier to exert their therapeutic effects. Histological changes in the brain and levels of Aβ were evaluated, and Y-maze and new object recognition experiments were conducted to assess the effects of Eri and Hom on Aβ_25–35-induced memory impairment in mice. The levels of oxidative stress and apoptosis in peripheral immune cells and progenitor cells in the hippocampal region were analyzed by flow cytometry and in vitro assays. Western blotting and enzyme-linked immunosorbent assays (ELISA) were used to measure the expression levels of NLRP3 inflammasome-related proteins and inflammatory factors in the brain. The effect of nigericin (an agonist of the NLRP3 inflammasome) on Eri and Hom intervention in LPS-induced N9 microglia was examined using a High Content Screening System. (3) Results: Eri and Hom reduced neuronal damage in mouse brain tissue, decreased Aβ levels in the brain, downregulated oxidative stress and apoptosis levels, and improved learning and memory capacity by crossing the blood–brain barrier to exert its effects. Moreover, Eri and Hom inhibited NLRP3 inflammasome activation and ameliorated immune cell disorder. Furthermore, the effect of Eri and Hom on LPS-induced N9 microglia disappeared after the addition of nigericin to agonize NLRP3 receptors. (4) Conclusions: Eri and Hom improved Aβ_25–35-induced memory impairment in mice by inhibiting the NLRP3 inflammasome.     

Molecular Mechanisms of Amylin Turnover,Misfolding and Toxicity in the Pancreas

Amyloidosis is a common pathological event in which proteins self-assemble into misfolded soluble and insoluble molecular forms, oligomers and fibrils that are often toxic to cells. Notably, aggregation-prone human islet amyloid polypeptide (hIAPP), or amylin, is a pancreatic hormone linked to islet β-cells demise in diabetics. The unifying mechanism by which amyloid proteins, including hIAPP, aggregate and kill cells is still matter of debate. The pathology of type-2 diabetes mellitus (T2DM) is characterized by extracellular and intracellular accumulation of toxic hIAPP species, soluble oligomers and insoluble fibrils in pancreatic human islets, eventually leading to loss of β-cell mass. This review focuses on molecular, biochemical and cell-biology studies exploring molecular mechanisms of hIAPP synthesis, trafficking and degradation in the pancreas. In addition to hIAPP turnover, the dynamics and the mechanisms of IAPP–membrane interactions; hIAPP aggregation and toxicity in vitro and in situ; and the regulatory role of diabetic factors, such as lipids and cholesterol, in these processes are also discussed.     

Ethanolic Extract from Pteris wallichiana Alleviates DSS-Induced Intestinal Inflammation and Intestinal Barrier Dysfunction by Inhibiting the TLR4/NF-κB Pathway and Regulating Tight Junction Proteins

The aim of the research was to determine the protective effect and mechanism of Pteris wallichiana J. Agardh extract (PWE) on DSS-induced ulcerative colitis (UC) in mice. In this research, PWE is rich in flavonoids and diterpenoids by UPLC-MS/MS analysis. In LPS-induced RAW264.7 cells, PWE reduced the productions of inflammatory factors (i.e., NO, TNF-α, IL-6, and IL-1β). In DSS-induced UC in mice, PWE improved disease activity index (DAI) score, attenuated oxidative stress by decreasing MPO and MDA activities and activating GSH and SOD levels, and inhibited TNF-α, IL-6, and IL-1β expressions in the colonic tissues. PWE also improved the intestinal barrier by upregulating the expressions of tight junction proteins, including occludin and ZO-1. Moreover, PWE extract alleviated intestinal inflammation by suppressing the TLR4/MyD88/NF-κB signaling pathway. Conclusion: PWE can alleviate DSS-induced UC in mice by increasing the expressions of intestinal tight junction proteins and inhibiting the TLR4/NF-κB inflammatory pathway.     

The Polyphenols α-Mangostin and Nordihydroguaiaretic Acid Induce Oxidative Stress,Cell Cycle Arrest,and Apoptosis in a Cellular Model of Medulloblastoma

Medulloblastoma is a common malignant brain tumor in the pediatric age. The current therapeutics present serious collateral effects. Polyphenols α-mangostin and nordihydroguaiaretic acid (NDGA) exert potent antitumoral activity in different cancer models, although their antitumoral effects have not been described in medulloblastoma cells yet. This study aimed to examine the proapoptotic effects of these polyphenols on human medulloblastoma cells. Medulloblastoma cell line Daoy was incubated with increasing concentrations of α-mangostin or NDGA for 24 h. The cell viability was analyzed using crystal violet and trypan blue dyes. Determination of the glutathione (GSH)/glutathione disulfide (GSSG) ratio and levels of carbonylated proteins was performed to evaluate the oxidative stress. Cell cycle progression and induction of cell death by fluorochrome-couple and TUNEL assays were evaluated using flow cytometry assays. Individual treatments with α-mangostin or NDGA decreased the viability of Daoy cells in a dose-dependent manner, inducing G2/M and S-G2/M cell cycle arrest, respectively. Both polyphenols induced cell death and increased oxidative stress. Very interestingly, α-mangostin showed more potent effects than NDGA. Our results indicate that α-mangostin and NDGA exert important cytostatic and cytotoxic effects in the Daoy cell line. These data highlight the potential usefulness of these compounds as an alternative strategy in medulloblastoma treatment.     

Cryptotanshinone Ameliorates Doxorubicin-Induced Cardiotoxicity by Targeting Akt-GSK-3β-mPTP Pathway In Vitro

Cardiotoxicity is one of the main side effects of doxorubicin (Dox) treatment. Dox could induce oxidative stress, leading to an opening of the mitochondrial permeability transition pore (mPTP) and apoptosis in cardiomyocytes. Previous studies have shown that Cryptotanshinone (Cts) has potential cardioprotective effects, but its role in Dox-induced cardiotoxicity (DIC) remains unknown. A Dox-stimulated H9C2 cell model was established. The effects of Cts on cell viability, reactive oxygen species (ROS), superoxide ion accumulation, apoptosis and mitochondrial membrane potential (MMP) were evaluated. Expressions of proteins in Akt-GSK-3β pathway were detected by Western blot. An Akt inhibitor was applied to investigate the effects of Cts on the Akt-GSK-3β pathway. The effects of Cts on the binding of p-GSK-3β to ANT and the formation of the ANT-CypD complex were explored by immunoprecipitation assay. The results showed that Cts could increase cell viability, reduce ROS levels, inhibit apoptosis and protect mitochondrial membrane integrity. Cts increased phosphorylated levels of Akt and GSK-3β. After cells were co-treated with an Akt inhibitor, the effects of Cts were abolished. An immunoprecipitation assay showed that Cts significantly increased GSK-3β-ANT interaction and attenuated Dox-induced formation of the ANT-CypD complex, thereby inhibiting opening of the mPTP. In conclusion, Cts could ameliorate oxidative stress and apoptosis via the Akt-GSK-3β-mPTP pathway.