6-shogaol attenuates H2O2-induced oxidative stress via upregulation of Nrf2-mediated γ-glutamylcysteine synthetase and heme oxygenase expression in HepG2 cells

Food Science and Biotechnology - The signaling pathway by which 6-shogaol protects HepG2 cells against H2O2-induced oxidative stress was investigated. Cellular anti-oxidant activities, the GSH...     

Tandem mass tag-based quantitative proteomics analysis reveals the effects of the α-lactalbumin peptides GINY and DQW on lipid deposition and oxidative stress in HepG2 cells

The objective of this study was to investigate the mechanism by which the α-lactalbumin peptides Gly-Ile-Asn-Tyr (GINY) and Asp-Gln-Trp (DQW) ameliorate free fatty acid–induced lipid deposition in HepG2 cells. The results show that GINY and DQW reduced triglyceride, total cholesterol, and free fatty acid levels significantly in free fatty acid–treated HepG2 cells. Based on proteomic analysis, GINY and DQW alleviated lipid deposition and oxidative stress mainly through the peroxisome proliferator-activated receptor (PPAR) pathway, fatty acid metabolism, oxidative phosphorylation, and response to oxidative stress. In vitro experiments confirmed that GINY and DQW upregulated the mRNA and protein expression of fatty acid β-oxidation–related and oxidative stress–related genes, and downregulated the mRNA and protein expression of lipogenesis-related genes by activating peroxisome proliferator-activated receptor α (PPARα). Meanwhile, GINY and DQW reduced free fatty acid–induced lipid droplet accumulation and reactive oxygen species generation, and enhanced the mitochondrial membrane potential and ATP levels. Furthermore, GINY and DQW enhanced carnitine palmitoyl-transferase 1a (CPT-1a) and superoxide dismutase activities, and diminished acetyl-coenzyme A carboxylase 1 (ACC1) and fatty acid synthase (FASN) activities in a PPARα-dependent manner. Interestingly, GW6471 (a PPARα inhibitor) weakened the effects of GINY and DQW on the PPARα pathway. Hence, our findings suggest that GINY and DQW have the potential to alleviate nonalcoholic fatty liver disease by activating the PPARα pathway.     

β-Hydroxybutyrate inhibits apoptosis in bovine neutrophils through activating ERK1/2 and AKT signaling pathways

Ketosis in dairy cows, a common metabolic disorder during the peripartal period, is accompanied by systemic inflammation and high concentrations of blood β-hydroxybutyrate (BHB). Neutrophil apoptosis plays a key role in maintaining the balance of inflammation and functional capacity of circulating neutrophils in ketotic cows. The kinases ERK1/2 and AKT, as well as their downstream Bcl-2 family-mediated mitochondrial signaling, are important apoptosis-regulating pathways in neutrophils. The objective of our study was to investigate the effects of BHB on neutrophil apoptosis and the underlying regulatory mechanisms during ketosis. Neutrophils were isolated from 5 multiparous cows (within 3 wk postpartum) with serum BHB concentrations <0.6 mM and glucose concentrations >3.5 mM. In a series of experiments, neutrophils were treated with increasing concentrations of BHB (0, 0.6, 2, and 3 mM for 10 h) and time (0, 2, 4, 6, 8, and 10 h with 2 mM). Subsequently, a 2 mM BHB dose was used to challenge neutrophils for 8 h. Apoptosis rate of neutrophils and protein abundance of cleaved caspase 3 were lower after BHB treatment. Treatment with BHB decreased protein and mRNA abundance of the pro-apoptotic genes Bax (BAX) and Bad (BAD), whereas it increased mitochondrial membrane potential (MMP) and protein and mRNA of the anti-apoptotic genes Bcl-xL (BCL2L1) and Mcl-1 (MCL1). This indicated that a mitochondrial pathway was involved in the inhibition of neutrophil apoptosis via BHB. In addition, both SCH772984 (an inhibitor of the ERK1/2 signaling pathway) and MK-2206 (an inhibitor of the AKT signaling pathway) alleviated the BHB-induced anti-apoptotic function of the Bcl-2 family and the inhibition of MMP. Overall, our data demonstrated that high concentrations of BHB inhibit apoptosis in bovine neutrophils by activating the ERK1/2 and AKT signaling pathways. These findings provide a theoretical basis for the understanding of systemic inflammation in ketotic cows.     

Catechin-7-O-β-d-glucopyranoside scavenges free radicals and protects human B lymphoma BJAB cells on H2O2-mediated oxidative stress

Catechin-7-O-β-d-glucopyranoside (CA-G) was previously isolated from red bean (the seed of Phaseolus calcaratus cv. Roxburgh). This study examined the ability of CA-G to scavenge reactive oxygen species generated by cell-free systems and to protect cells from oxidative stress caused by hydrogen peroxide (H₂O₂). The mechanism by which CA-G exerts its antioxidant and anti-apoptotic action on H₂O₂-exposed cells was also investigated. CA-G treatment prevented H₂O₂-mediated apoptosis and inhibited the formation of single stand breaks in DNA in H₂O₂-exposed BJAB cells. CA-G suppressed mitochondrial stress and caspase activation caused by H₂O₂. Mechanistic experiments revealed that the antioxidant mechanism of CA-G on H₂O₂-mediated oxidative damage was due to the direct scavenging of hydroxyl radicals and/or to the chelation of metal ions that were used to produce hydroxyl radicals from H₂O₂ via the Fenton reaction. Collectively, these findings suggest beneficial roles of CA-G or CA-G-rich red bean on the protection from oxidative damage.     

Japanese apricot extract attenuates nuclear factor-κB activation and proteasomal activity in A549 lung cancer cells

The present study investigated the mechanism of Japanese apricot extract (JAE) in inhibiting lung cancer cells proliferation. JAE inhibited A549 lung cancer cell proliferation at non-cytotoxic doses and suppressed nuclear factor-κB (NF-κB) activation induced by TNF-α at a dose of 1 mg/mL (p<0.05). Proteasome activities of A549 cells were blocked by JAE in a dose-dependent manner at concentrations of 0.67 and 1 mg/mL (p<0.05). These results indicate that JAE has anti-proliferative activity against A549 cells and suppresses NF-κB activation, partially due to inhibiting proteasome activity.     

Oxidative stress,NF-κB signaling,NLRP3 inflammasome,and caspase apoptotic pathways are activated in mammary gland of ketotic Holstein cows

Ketosis is a serious metabolic disorder characterized by systemic and hepatic oxidative stress, inflammation, and apoptosis, as well as reduced milk yield. Because of the paucity of data on mammary responses during ketosis, the aim of this study was to evaluate alterations in oxidative stress, NF-κB signaling, NLRP3 inflammasome, and caspase apoptotic pathways in mammary gland of dairy cows with ketosis. Blood, mammary gland tissue, and milk samples were collected from healthy cows [Control, blood concentration of β-hydroxybutyrate (BHB) <0.6 mM, n = 10] and cows with subclinical ketosis (SCK, blood concentration of BHB >1.2 mM and <3 mM, n = 10) or clinical ketosis (CK, blood concentration of BHB >3 mM, n = 10) at median 8 d in milk (range = 6–12). Compared with Control, serum concentration of glucose was lower (3.91 vs. 2.86 or 2.12 mM) in cows with SCK or CK, whereas concentrations of fatty acids (0.25 vs. 0.57 or 1.09 mM) and BHB (0.42 vs. 1.81 or 3.85 mM) were greater. Compared with Control, the percentage of milk fat was greater in cows with SCK or CK. In contrast, the percentage of milk protein was lower in cows with SCK or CK. We detected no differences in milk lactose content across groups. Compared with Control, activities of glutathione peroxidase, superoxide dismutase, and catalase were lower in mammary gland tissue of cows with SCK or CK. In contrast, concentrations of hydrogen peroxide and malondialdehyde were greater in cows with SCK or CK. Compared with Control, mRNA abundances of TNFA, IL6, and IL1B were greater in mammary tissues of cows with SCK or CK. In addition, activity of IKKβ and the ratio of phosphorylated inhibitor of κBα to IκBα, and of phosphorylated NF-κB p65 to NF-κB p65, were also greater in mammary tissues of cows with SCK or CK. Subclinical or clinical ketosis also led to greater activity of caspase 1 and protein abundance of caspase 1, NLRP3, Bax, caspase 3, and caspase 9. In contrast, abundance of the antiapoptotic protein was lower in SCK or CK cows. The data indicate that the mammary gland of SKC or CK cows undergoes severe oxidative stress, inflammation, and cell death.     

Investigation and comparison of the anti-tumor activities of lactoferrin, α-lactalbumin,and β-lactoglobulin in A549, HT29, HepG2, and MDA231-LM2 tumor models

To investigate the anti-tumor activities of lactoferrin, α-lactalbumin, and β-lactoglobulin, 4 types of human tumor cells (lung tumor cell A549, intestinal epithelial tumor cell HT29, hepatocellular cell HepG2, and breast cancer cell MDA231-LM2) were exposed to 3 proteins, respectively. The effects on cell proliferation, migration, and apoptosis were detected in vitro, and nude mice bearing tumors were administered the 3 proteins in vivo. Results showed that the 3 proteins (20 g/L) inhibited viability and migration, as well as induced apoptosis, in 4 tumor cells to different degrees (compared with the control). In vivo, tumor weights in the HT29 group (0.84 ± 0.22 g vs. control 2.05 ± 0.49 g) and MDA231-LM2 group (1.11 ± 0.25 g vs. control 2.49 ± 0.57 g) were significantly reduced by lactoferrin; tumor weights in the A549 group (1.07 ± 0.19 g vs. control 3.11 ± 0.73 g) and HepG2 group (2.32 ± 0.46 g vs. control 3.50 ± 0.74 g) were significantly reduced by α-lactalbumin. Moreover, the roles of lactoferrin, α-lactalbumin, and β-lactoglobulin in regulating apoptotic proteins were validated. In summary, lactoferrin, α-lactalbumin, and β-lactoglobulin were proven to inhibit growth and development of A549, HT29, HepG2, and MDA231-LM2 tumors to different degrees via induction of cell apoptosis.     

Antifatigue effects of anshenyizhi compound in acute excise-treated mouse via modulation of AMPK/PGC-1α-related energy metabolism and Nrf2/ARE-mediated oxidative stress

The anshenyizhi compound (AC), a mixture from Chinese medicine herbs, has numerous biological effects. In the present study, the acute exercise-treated mice model was established to explore the antifatigue properties of AC and its underlying mechanisms. AC increased exercise endurance in the weight-loaded forced swimming test and rota-rod test. The antifatigue properties of AC were closely correlated with enhancing the body's exercise endurance by increasing the levels of cyanmethemoglobin, testosterone/corticosterone, and creatine kinase, while decreasing the levels of lactic acid, lactate dehydrogenase, and blood urea nitrogen in serum. Moreover, our results confirmed the antioxidant ability of AC by improving the activities of superoxide dismutase while reducing reactive oxygen species and malondialdehyde levels in serum. The AC also improved the storage of glycogen by increasing the levels of succinate dehydrogenase, and malate dehydrogenase in liver and muscle. Additionally, AC displayed the antifatigue and antiapoptosis effects via regulating Nrf2-mediated oxidative stress, AMPK-related glucose metabolism, and p53 pathways. Our experimental results first provided a support that AC had effects on antifatigue through regulating AMPK/PGC-1α-related energy metabolism and Nrf2/ARE-mediated oxidative stress. Consequently, AC could be developed into a new functional food supplement for the prevention and treatment of diseases related to fatigue in the future.     

A lupin protein hydrolysate protects the central nervous system from oxidative stress in WD-fed ApoE−/− mice

Oxidative stress plays a crucial role in neurodegenerative diseases like Parkinson's and Alzheimer's. Studies indicate the relationship between oxidative stress and the brain damage caused by a high-fat diet. It is previously found that a lupin protein hydrolysate (LPH) has antioxidant effects on human leukocytes, as well as on the plasma and liver of Western diet (WD)-fed ApoE^−/− mice. Additionally, LPH shows anxiolytic effects in these mice. Given the connection between oxidative stress and anxiety, this study aimed to investigate the antioxidant effects of LPH on the brain of WD-fed ApoE^−/− mice. LPH (100 mg kg⁻¹) or a vehicle is administered daily for 12 weeks. Peptide analysis of LPH identified 101 amino acid sequences (36.33%) with antioxidant motifs. Treatment with LPH palliated the decrease in total antioxidant activity caused by WD ingestion and regulated the nitric oxide synthesis pathway in the brain of the animals. Furthermore, LPH increased cerebral glutathione levels and the activity of catalase and glutathione reductase antioxidant enzymes and reduced the 8-hydroxy-2’-deoxyguanosine levels, a DNA damage marker. These findings, for the first time, highlight the antioxidant activity of LPH in the brain. This hydrolysate could potentially be used in future nutraceutical therapies for neurodegenerative diseases.     

Glutamine pretreatment protects bovine mammary epithelial cells from inflammation and oxidative stress induced by γ-d-glutamyl-meso-diaminopimelic acid (iE-DAP)

Glutamine (GLN) has many types of biological activity in rats, including anti-inflammatory, antioxidative stress, and anti-apoptosis effects. However, little is known about the effects of GLN on bovine mammary epithelial cells (BMEC). γ-d-Glutamyl-meso-diaminopimelic acid (iE-DAP) is a cell wall peptidoglycan component of gram-negative bacteria that can be recognized by the intracellular receptor nucleotide-binding oligomerization domain-containing protein 1 (NOD1) and can cause bovine mastitis. The goal of the present study was to investigate whether GLN protects BMEC from iE-DAP–induced inflammation, oxidative stress, and apoptosis. We cultured BMEC in a GLN-free medium for 24 h and then separated them into 4 groups: cells treated with 1× PBS for 26 or 32 h (control); cells stimulated by 10 μg/mL iE-DAP for 2 or 8 h (2- or 8-h iE-DAP); cells pretreated with 8 or 4 mM GLN for 24 h followed by 2 or 8 h of 1× PBS treatment (8 or 4 mM GLN); and cells pretreated with 8 or 4 mM GLN for 24 h followed by 2 or 8 h of iE-DAP treatment (DG). In the 2-h iE-DAP group, when levels of inflammation peaked, iE-DAP treatment increased both the mRNA and protein expression of NOD1, inhibitor of nuclear factor-κB (NFKBIA, IκB), and nuclear factor-κB subunit p65 (RELA, NF-κB p65), as well as the mRNA expression of IL6 and IL8 and levels of IL-6 and tumor necrosis factor-α in cell culture supernatants. In contrast, 8 mM GLN pretreatment inhibited the mRNA and protein expression of inflammatory-related factors by suppressing the NOD1/NF-κB pathway. In the 8-h iE-DAP group, iE-DAP treatment decreased the mRNA and protein expression of extracellular regulated kinase (Erk, ERK) and nuclear factor erythroid 2–associated factor2 (NFE2L2, Nrf2), as well as the mRNA expression of superoxide dismutase 1 (SOD1), catalase (CAT), coenzyme II oxidoreductase 1 (NQO1), and heme oxygenase 1 (HMOX1, HO1). In addition, iE-DAP treatment increased the expression of malondialdehyde in BMEC when oxidative stress levels peaked. Interestingly, 4 mM GLN pretreatment induced the mRNA and protein expression of antioxidative stress–related factors and inhibited the expression of reactive oxygen species in BMEC by promoting the ERK/Nrf2 pathway. Moreover, GLN reduced apoptosis caused by inflammation and oxidative stress in BMEC. This is the first report showing that GLN protects against iE-DAP-induced inflammation and oxidative stress via the NOD1/NF-κB and ERK/Nrf2 pathways in BMEC.     

β-Casomorphin-7 cause decreasing in oxidative stress and inhibiting NF-κB-iNOS-NO signal pathway in pancreas of diabetes rats

β-Casomorphin-7 (β-CM-7) is a milk biological active peptide. The present study is aimed to investigate the protective effects of β-CM-7, against oxidative stress in pancreas of streptozotocin-induced diabetic rats by assaying malondialdehyde (MDA), nitric oxide (NO) level, the activity of enzymatic antioxidants such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and NF-κB, inducible nitric oxide synthase (iNOS) gene expression. A significant increase in the level of oxidative stress was observed in pancreas of the diabetic rats when compared to control rats. After 15 d oral administration of β-CM-7 (7.5 × 10(-8) mol/d), the pancreas MDA level was markedly reduced. Oral administration of β-CM-7 to diabetic rats showed an obviously increase in the activity of catalase in pancreas, oral administration of β-CM-7 to the diabetic group of rats also showed a reduction of NF-κB and iNOS gene expression in pancreas. The elevated pancreas NO level was markedly reduced by the oral administration of β-CM-7. Thus, the results of the present study suggest that β-CM-7 may cause protective effects such as pronounced decreasing in oxidative stress and inhibiting NF-κB-iNOS-NO signal pathway in pancreas of diabetes rats.     

Amelioration of cadmium-induced oxidative stress, impairment in lipids and plasma lipoproteins by the combined treatment with quercetin and α-tocopherol in rats

Cadmium (Cd) exposure results in numerous pathological consequences including oxidative stress and dyslipidemia. The present study was designed to investigate the efficacy of combined treatment with quercetin (QE) and α-tocopherol (AT) against Cd-induced oxidative stress and alterations in lipids and lipoproteins in the plasma and liver of rats. Oral administration of Cd (5 mg/kg bw/d) for 4 wk has shown a significant (P < 0.05) increase in thiobarbituric acid reactive substances (TBARS), lipid hydro peroxides (LOOH), total cholesterol, low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), free fatty acids (FFA), phospholipids (PL), triglycerides (TGs), and the activity of hydroxyl-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) in plasma with a significant (P > 0.05) reduction in the levels of reduced glutathione (GSH), high density lipoprotein cholesterol (HDL-C), and the activity of lecithin cholesterol acyl transferase (LCAT) in plasma. In addition, the levels of hepatic thiobarbituric acid reactive substances (TBARS), LOOH, conjugated dienes (CD), protein carbonyls (PC), and the activity of HMG-CoA reductase, levels of cholesterol, FFA, and TGs were significantly (P > 0.05) increased and the level of PL is significantly (P > 0.05) decreased along with the decreased activity of LCAT in the liver of Cd-treated rats. Oral supplementation with QE (50 mg/kg bw/d) and AT (50 mg/kg bw/d) for 4 wk in Cd intoxicated rats significantly (P > 0.05) has reduced the plasma levels of TBARS, LOOH, GSH, cholesterol, FFA, TGs, VLDL-C, LDL-C, and the activity of HMG-CoA and significantly (P > 0.05) has increased the activity of LCAT and the plasma levels of HDL-C. The oral supplementation also significantly (P > 0.05) has reduced the hepatic oxidative stress markers, cholesterol, TGs, FFA, and significantly (P > 0.05) has increased the LCAT activity and the PL in liver. Our results indicate that the combined treatment with QE and AT has normalized all the previously mentioned biochemical parameters in Cd-intoxicated rats than the individual treatments. The combined treatment has provided remarkable protection against Cd-induced oxidative stress and alterations in lipid metabolism and, thereby, reduced the Cd-mediated cardiovascular diseases.     

Apple extracts attenuate tumor necrosis factor-α-induced nuclear factor-κB activation by inhibiting IκB kinase and proteasome in A549 human non-small lung carcinoma cells

Apples contain a variety of phytochemicals and health benefits of apple consumption are widely recognized in reducing the risks of chronic diseases such as cancer. However, the mechanisms of apples in inhibiting lung cancer cell proliferation are not fully understood. The present study examined the role of apple extracts in suppressing nuclear factor (NF)-κB activation in A549 human lung cancer cells. Incubation with apple extracts at doses of 10 and 20 mg(fresh apple)/mL significantly inhibited tumor necrosis factor (TNF)-α-induced NF-κB activation in A549 cells (p<0.05). Apple extracts suppressed phosphorylation of inhibitor of NF-κB (IκB-α) at doses of 10 and 20 mg (fresh apple)/mL and inhibited proteasomal activity at doses of 5, 10, and 20 mg(fresh apple)/mL (p<0.05). These results indicate that apple extracts inhibit TNF-α-induced NF-κB activation in A549 lung cancer cells by suppressing both of IκB kinase (IKK) activity and proteasomal activity.     

Apocynin exerts neuroprotective effects in fumonisin b1–induced neurotoxicity via attenuation of oxidative stress and apoptosis in an animal model

The Fusarium verticillioides produces a mycotoxin, that is, fumonisin b1 (Fb1), which commonly infects corn and agricultural commodities. The Fb1 showed hepatotoxicity, neurotoxicity, and carcinogenicity in animals. Hence, the present investigation aimed to evaluate the effect of apocynin (AP) on Fb1-induced neurotoxic effects and its mechanism in the mice model and cell line. The male Balb/c mice, with the 6.75 mg/kg bwt of Fb1 were injected subcutaneously for 5 days to induce neurotoxicity. A significant elevation of serotonin (5-HT) was observed in mice treated with Fb1 in the whole brain showing biogenic amines may reflect Fb1 neurotoxicity, but the negatively regulated mechanisms were attenuated by the pretreatment of AP. In addition, AP pretreatment normalized apoptotic changes in histology and immunohistochemistry studies. In Western blotting studies, apoptotic genes were upregulated and oxidative stress genes were downregulated due to Fb1 treatment; while treating with AP, these gene expressions were rectified. Further cell cytotoxicity was investigated by MTT and lactate dehydrogenase (LDH) assays in SH-SY5Y cell line. MTT and LDH assays indicated the IC₅₀ value to be 150 µM of Fb1, which was protected by 100 µg of AP. The electron microscopy evaluated the Fb1-induced apoptotic conditions and its cell morphology recovery by AP. These results suggest that nicotinamide adenine dinucleotide phosphate hydrogen oxidase–mediated reactive oxygen species is the primary upstream signal leading to increased Fb1-mediated neurotoxicity in mice. The use of the antioxidant AP reversed the toxin-induced oxidative stress and apoptosis by its antioxidant potency.     

Fermented sea tangle attenuates oxidative stress in individuals with a high level of γ-glutamyltransferase: A randomized,double-blind,and placebo-controlled clinical study

A randomized, double-blind, placebo-controlled study of fermented sea tangle (FST) was conducted using 48 healthy volunteers with high levels of γ-glutamyltransferase (GGT). Participants (n=48) were divided into a placebo group and a FST group, which consumed FST (1.5 g/day) for 4 weeks. Serum GGT, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were determined. Plasma 8-isoprostane, 8-hydroxydeoxyguanosine (8-OHdG), and protein carbonyl contents, which indicate lipid peroxidation, DNA damage, and oxidation of protein, were determined. Decreased serum GGT was found in FST consumption group, compared to the placebo group [mean values (IU/L): 78.71±19.14 and 116.75±38.55, respectively, p<0.001]. Administration of FST significantly (p<0.05) decreased levels of serum AST [mean values (IU/L): 31.08±7.25 and 26.79±6.53 respectively, p<0.001] and ALT [mean values (IU/L): 42.63±18.99 and 31.83±14.21, respectively, p=0.001], compared to the placebo group, and significantly (p<0.05) decreased concentrations of plasma 8-isoprostane, 8-OHdG, and protein carbonyl levels.