Acetylated oligopeptide and N-acetylcysteine protect against iron overload-induced dentate gyrus hippocampal degeneration through upregulation of Nestin and Nrf2/HO-1 and downregulation of MMP-9/TIMP-1 and GFAP

Iron accumulation in the brain causes oxidative stress, blood-brain barrier (BBB) breakdown, and neurodegeneration. We examined the preventive effects of acetylated oligopeptides (AOP) from whey protein on iron-induced hippocampal damage compared to N-acetyl cysteine (NAC). This 5-week study used 40 male albino rats. At the start, all rats received 150 mg/kg/day of oral NAC for a week. The 40 animals were then randomly divided into four groups: Group I (control) received a normal diet; Group II (iron overload) received 60 mg/kg/day intraperitoneal iron dextran 5 days a week for 4 weeks; Group III (NAC group) received 150 mg/kg/day NAC and iron dextran; and Group IV (AOP group) received 150 mg/kg/day AOP and iron dextran. Enzyme-linked immunosorbent assay, spectrophotometry, and qRT-PCR were used to measure MMP-9, tissue inhibitor metalloproteinase-1 (TIMP-1), MDA, reduced glutathione (GSH) levels, and nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) gene expression. Histopathological and immunohistochemical detection of nestin, claudin, caspase, and GFAP was also done. MMP-9, TIMP-1, MDA, caspase, and GFAP rose in the iron overload group, while GSH, Nrf2, HO-1, nestin, and claudin decreased. The NAC and AOP administrations improved iron overload-induced biochemical and histological alterations. We found that AOP and NAC can protect the brain hippocampus from iron overload, improve BBB disruption, and provide neuroprotection with mostly no significant difference from healthy controls.

Diclofenac and eugenol hybrid with enhanced anti-inflammatory activity through activating HO-1 and inhibiting NF-κB pathway in vitro and in vivo

A series of diclofenac hybrid molecules were synthesized and evaluated for their NO-inhibitory ability in LPS-induced RAW 264.7 macrophage cells. Among them, compound 1 showed the highest NO-inhibitory ability (approximately 66%) and no significant cytotoxicity. Compound 1 exhibited superior NF-κB-inhibitory ability compared to diclofenac through the activation of Nrf2/HO-1 signaling pathway in RAW 264.7. 20 mg/kg compound 1 resulted in remarkable colitis improvement in dextran sulfate sodium (DSS)-induced mice model by up-regulating HO-1 and down-regulating phosphorylation level of NF-κB p65. Moreover, 50 mg/kg dose of compound 1 showed a lower ulcerogenic potential compared to diclofenac in rats. The diclofenac-eugenol hybrid (compound 1) may serve as a novel anti-inflammatory agent based on its role in inhibiting the NF-κB signaling pathway and activating HO-1 expression with no toxicity in vitro and in vivo.

Hesperidin methylchalcone (HMC) hinders amyloid-β induced Alzheimer's disease by attenuating cholinesterase activity, macromolecular damages, oxidative stress and apoptosis via regulating NF-κB and Nrf2/HO-1 pathways

Phytocompounds therapy has recently emerged as an effective strategy to treat Alzheimer's disease. Herein, the protective effect of hesperidin methylchalcone (HMC) was evaluated through Alzheimer's disease models of Neuro-2a cells and Wistar rats. The in vitro results showed that HMC possesses significant ability to inhibit the acetylcholinesterase enzyme and exhibiting anti-aggregation and disaggregation properties. Furthermore, HMC could protect the Neuro-2a cells against Aβ-induced neurotoxicity. Simultaneously, HMC treatment significantly improved the cognitive deficits caused by Aβ-peptide on spatial memory in Wistar rats. HMC significantly enhanced the cholinergic effects by inhibiting AChE, BuChE, β-secretase activity, caspase-3 activity, and attenuating macromolecular damages and apoptosis. Notably, HMC reduced the Aβ-induced oxidative stress by activating the antioxidative defence enzymes. In addition, the HMC treatment suppressed the expression of immunocytokines such as p-NF-κB p65, p-IκBα, induced by Aβ; whereas upregulating Nrf2, HO-1 in brain homogenate. These results suggest that HMC could attenuate Aβ-induced neuroinflammation in brain via suppressing NF-κB signalling pathway and activating the Nrf2/HO-1 pathway, thereby improving memory and cognitive impairments in Wistar rats. Overall, the present study reports that HMC can act as a potent candidate with multi-faceted neuroprotective potential against Aβ-induced memory dysfunction in Wistar rats for the treatment of Alzheimer's disease.

Blueberry-derived exosomes-like nanoparticles ameliorate nonalcoholic fatty liver disease by attenuating mitochondrial oxidative stress

Accumulating evidence indicates that mitochondrial dysfunction and oxidative stress play a pivotal role in the initiation and progression of nonalcoholic fatty liver disease (NAFLD). In this study, we found that blueberry-derived exosomes-like nanoparticles (BELNs) could ameliorate oxidative stress in rotenone-induced HepG2 cells and high-fat diet (HFD)-fed C57BL/6 mice. Preincubation with BELNs decreased the level of reactive oxygen species (ROS), increased the mitochondrial membrane potential, and prevented cell apoptosis by inducing the expression of Bcl-2 and heme oxygenase-1 (HO-1) and decreasing the content of Bax in rotenone-treated HepG2 cells. We also found that preincubation with BELNs accelerated the translocation of Nrf2, an important transcription factor of antioxidative proteins, from the cytoplasm to the nucleus in rotenone-treated HepG2 cells. Moreover, administration of BELNs improved insulin resistance, ameliorated the dysfunction of hepatocytes, and regulated the expression of detoxifying/antioxidant genes by affecting the distribution of Nrf2 in the cytoplasm and nucleus of hepatocytes of HFD-fed mice. Furthermore, BELNs supplementation prevented the formation of vacuoles and attenuated the accumulation of lipid droplets by inhibiting the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase 1 (ACC1), the two key transcription factors for de novo lipogenesis in the liver of HFD-fed mice. These findings suggested that BELNs can be used for the treatment of NAFLD because of their antioxidative activity.

Effect of Polygonatum odoratum ethanol extract on high glucose-induced tubular epithelial cell apoptosis and oxidative stress

This work aims to analyze the effect of the ethanol extract from Polygonatum odoratum on high glucose-induced tubular epithelial cell apoptosis and oxidative stress. HK-2 injury of tubular epithelial cells was induced by high glucose, and the ethanol extract from Polygonatum odoratum was given. HK-2 cell activity and apoptosis were detected by MTT method and flow cytometry, respectively. Western blot was performed to analyze Cleaved-caspase3, Pro-caspase3, Nrf2, HO-1 protein expression. The levels of MDA, GSH, SOD were evaluated using commercial Kit. si-Nrf2 was transfected into HK-2 cells and high-glucose induction and ethanol extract from Polygonatum odoratum were given to observe the changes of cell apoptosis and oxidative stress. Ethanol extract from Polygonatum odoratum increased the high glucose-induced HK-2 cell activity, Pro-caspase3, Nrf2, HO-1 protein, GSH, SOD levels and decreased its apoptosis rate, Cleaved-caspase3 protein and MDA levels, showing statistically significant difference (p<0.05). After Nrf2 interference, high glucose-induced HK-2 cell activity, Pro-caspase3 protein, GSH, and SOD levels were decreased under the action of ethanol extract from Polygonatum odoratum, while the apoptosis rate, Cleaved-caspase3 protein, and MDA levels were increased significantly (p<0.05). The ethanol extract from Polygonatum odoratum can inhibit high glucose-induced tubular epithelial cell apoptosis and reduce oxidative stress by activating the Nrf2-ARE signaling pathway.

Heme Oxygenase-1 Contributes to Both the Engulfment and the Anti-Inflammatory Program of Macrophages during Efferocytosis

Heme oxygenase-1 (HO-1) plays a vital role in the catabolism of heme and yields equimolar amounts of biliverdin, carbon monoxide, and free iron. We report that macrophages engulfing either the low amount of heme-containing apoptotic thymocytes or the high amount of heme-containing eryptotic red blood cells (eRBCs) strongly upregulate HO-1. The induction by apoptotic thymocytes is dependent on soluble signals, which do not include adenylate cyclase activators but induce the p38 mitogen-activated protein (MAP) kinase pathway, while in the case of eRBCs, it is cell uptake-dependent. Both pathways might involve the regulation of BTB and CNC homology 1 (BACH1), which is the repressor transcription regulator factor of the HO-1 gene. Long-term continuous efferocytosis of apoptotic thymocytes is not affected by the loss of HO-1, but that of eRBCs is inhibited. This latter is related to an internal signaling pathway that prevents the efferocytosis-induced increase in Rac1 activity. While the uptake of apoptotic cells suppressed the basal pro-inflammatory cytokine production in wild-type macrophages, in the absence of HO-1, engulfing macrophages produced enhanced amounts of pro-inflammatory cytokines. Our data demonstrate that HO-1 is required for both the engulfment and the anti-inflammatory response parts of the efferocytosis program.

Anti-inflammatory and antibacterial activities of Pyrrosia petiolosa ethyl acetate (PPEAE) against Staphylococcus aureus in mice

P. petiolosa as a typical Chinese herbal medicine has been generally utilized as Chinese native medicine formulation for treatment of chronic bronchitis, bronchial asthma and pneumoconiosis. The objective of this study was to evaluate the anti-inflammatory and antibacterial activities of P. petiolosa ethyl acetate extract (PPEAE) against S. aureusin mice. In our study, mice were infected pneumonia by S. aureus, colonization of S. aureus in lung tissue was calculated and the number of white blood cells (WBC) in blood was measured. Meanwhile, the hematoxylin-eosin staining (H&E) was observed and the Real-time PCR was employed to determine the relative mRNA expression. The results showed that, after treated with PPEAE the wet/dry (W/D) weight ratio and the number of WBC decreased dramatically, the number of S. aureus was significantly reduced. Furthermore, H&E staining showed that PPEAE obviously relieved the inflammation of infected mice and real-time PCR results indicated that PPEAE significantly down regulated the inflammatory iNOS, TNF-α and up regulated the anti-inflammatory HO-1 mRNA. In summary, our study revealed that application of crude product PPEAE had prominent antibacterial activity against S. aureus. PPEAE significantly reduced the biomass of S. aureus and effectively relieved the inflammation of S. aureus-induced pneumonia.

Single-arm, open-label pilot intervention study to investigate an effect of oral 5-aminolevulinic acid plus sodium ferrous citrate on glucocorticoid reduction in patients with adult-onset Still disease: Study protocol for clinical trial (SPIRIT compliant)

BACKGROUND

Glucocorticoids are an important class of medication for patients with adult-onset Still disease (AOSD), however, relapse following glucocorticoid reduction and adverse events due to long-term effects of glucocorticoid are still problematic. It is of course essential to minimize the risk of treatment. Immunosuppressive therapies such as methotrexate and biologics including tocilizumab are used in glucocorticoid-dependent patients with AOSD, but no second-line treatments for patients with glucocorticoid dependence have been established yet. Given that these drugs also have the potential to cause adverse events, alternative treatments are sought. Recently, elevated heme oxygenase-1 (HO-1) has been reported in the serum of patients with AOSD, suggesting that HO-1 activity contributes to AOSD pathogenesis and may represent a new therapeutic target for the treatment of AOSD. The amino acid 5-aminolevulinic acid (5-ALA) is a non-proteinogenic δ amino acid in human body. An addition of ferrous iron to 5-ALA enhances heme biosynthesis. The increase in heme in vivo induces HO-1 production, a heme-degrading enzyme. Elevated HO-1 has been suggested to contribute to the pathogenesis of AOSD, and administration of 5-ALA and ferrous iron may be a potential treatment for AOSD.

METHODS/DESIGN

This study is a single-arm, open-label pilot intervention study using clinical endpoints to investigate the effects of oral 5-ALA with sodium ferrous citrate on glucocorticoid reduction in patients with AOSD receiving glucocorticoid therapy.

DISCUSSION

This pilot intervention study will provide evidence regarding the effectiveness and safety of 5-ALA/sodium ferrous citrate as a potential new therapeutic agent for glucocorticoid-dependent patients with AOSD.

TRIAL REGISTRATION

This study was registered in the Japan Registry of Clinical Trials (https://jrct.niph.go.jp) on January 14, 2020 as jRCTs071190042.

The role of Nrf2 in astragaloside IV-mediated antioxidative protection on heart failure

CONTEXT

Heart failure is one of the most serious diseases worldwide. Astragaloside IV (ASI) is widely used in the treatment of cardiovascular diseases.

OBJECTIVE

To elucidate the antioxidative mechanism of ASI in a rat model of left coronary artery ligation.

MATERIALS AND METHODS

Left coronary artery of Sprague-Dawley rats was ligated to establish the model of heart failure, and then vehicle (saline) or ASI (1 mg/kg/day) was orally administered to the rats (n = 15) for 6 weeks. Echocardiography was used to evaluate the cardiac function. Myocardial infarct size was measured by triphenyltetrazolium chloride staining. Oxidative stress in the ventricular myocardium was determined. Molecular mechanisms were investigated by Western blot and chromatin immunoprecipitation.

RESULTS

ASI improved the cardiac function, especially ejection fraction (75.27 ± 5.75% vs. 36.26 ± 4.14%) and fractional shortening (45.39 ± 3.66% vs. 17.88 ± 1.32%), and reduced the infarct size of left ventricle (20.69 ± 2.98% vs. 39.11 ± 3.97%). ASI maintained the levels of glutathione, catalase and superoxide dismutase and prevented the leakage of creatine kinase. In addition, ASI induced the protein expression of Nrf2 (1.97-fold) and HO-1 (2.79-fold), while reduced that of Keap-1 (0.77-fold) in the ventricular myocardium. In H9c2 cells, a rat cardiomyocyte cell line, ASI induced the translocation of Nrf2 from cytoplasm to nucleus, followed by transcriptional activation of NQO-1 (8.27-fold), SOD-2 (3.27-fold) and Txn-1 (9.83-fold) genes.

DISCUSSION AND CONCLUSIONS

ASI prevented heart failure by counteracting oxidative stress through the Nrf2/HO-1 pathway. Application in clinical practice warrants further investigation.

Transcriptome Investigation and In Vitro Verification of Curcumin-Induced HO-1 as a Feature of Ferroptosis in Breast Cancer Cells

Ferroptosis is a form of oxidative cell death and has become a chemotherapeutic target for cancer treatment. Curcumin (CUR), a well-known cancer inhibitor, significantly inhibits the viability of breast cancer cells. Through transcriptomic analysis and flow cytometry experiments, it was found that after 48 hours of treatment of breast cancer cells at its half maximal inhibitory concentration (IC50), curcumin suppressed the viability of cancer cells via induction of ferroptotic death. Use of the ferroptosis inhibitor ferrostatin-1 and the iron chelator deferoxamine rescued cell death induced by curcumin. Furthermore, in subsequent cell validation experiments, the results showed that curcumin caused marked accumulation of intracellular iron, reactive oxygen species, lipid peroxides, and malondialdehyde, while glutathione levels were significantly downregulated. These changes are all manifestations of ferroptosis. Curcumin upregulates a variety of ferroptosis target genes related to redox regulation, especially heme oxygenase-1 (HO-1). Using the specific inhibitor zinc protoporphyrin 9 (ZnPP) to confirm the above experimental results showed that compared to the curcumin treatment group, treatment with ZnPP not only significantly improved cell viability but also reduced the accumulation of intracellular iron ions and other ferroptosis-related phenomena. Therefore, these data demonstrate that curcumin triggers the molecular and cytological characteristics of ferroptosis in breast cancer cells, and HO-1 promotes curcumin-induced ferroptosis.

Roles of JNK/Nrf2 Pathway on Hemin-Induced Heme Oxygenase-1 Activation in MCF-7 Human Breast Cancer Cells

Heme oxygenase-1 (HO-1) is highly induced in various human disease states, including cancer, indicating that HO-1 is an emerging target of cancer therapy. In this study, we investigated that the mechanisms of hemin-induced HO-1 expression and its signaling pathways in human breast cancer cell. We used MCF-7 cells, a human breast cancer cell line. Hemin increased HO-1 expression in MCF-7 cells in a dose- and time-dependent manner. Hemin enhanced HO-1 expression through the activation of c-Jun N-terminal kinases (JNK) signaling pathway. Hemin also induced activation of Nrf2, a major transcription factor of HO-1 expression. These responses in MCF-7 cells were completely blocked by pretreatment with brazilin, a HO-1 regulator. These results indicated that brazilin inhibits hemin-induced HO-1 expressions through inactivation of JNK/Nrf2 in MCF-7 cells. Thus, our findings suggest that HO-1 is an important anticancer-target of brazilin in human breast cancer.

Anti-oxidative and anti-adipogenic effects of caffeine in an in vitro model of Graves' orbitopathy

Oxidative stress and adipogenesis play key roles in the pathogenesis of Graves' orbitopathy (GO). In this study, the therapeutic effects of caffeine on the reduction of oxidative stress and adipogenesis were evaluated in primary cultured GO orbital fibroblasts in vitro. Orbital fibroblasts were cultured from orbital connective tissues obtained from individuals with GO. Intracellular reactive oxygen species (ROS) levels induced by hydrogen peroxide or cigarette smoke extract and the expression of anti-oxidative enzymes were measured after caffeine treatment. After adipogenic differentiation and caffeine treatment, cells were stained with Oil Red O and the levels of peroxisome proliferator activator γ (PPARγ), C/EBPα, and C/EBPβ were determined by western blot analysis. Hydrogen peroxide and cigarette smoke extract increased the levels of intracellular ROS and anti-oxidative enzymes, which decreased in a dose-dependent manner upon pretreatment with caffeine in GO orbital fibroblasts. Oil Red-O staining results revealed a decrease in lipid droplets; furthermore, PPARγ, C/EBPα, and C/EBPβ protein expression levels were inhibited upon treatment with caffeine during adipocyte differentiation. In conclusion, caffeine decreased oxidative stress and adipogenesis in GO orbital fibroblasts in vitro. These findings may contribute to the development of new types of caffeine-containing pharmacological agents for use in the management of GO.

Impairment of Nrf2- and Nitrergic-Mediated Gastrointestinal Motility in an MPTP Mouse Model of Parkinson's Disease

BACKGROUND

Gastrointestinal (GI) motility dysfunction is the most common non-motor symptom of Parkinson's disease (PD). Studies have indicated that GI motility functions are impaired before the onset of PD.

AIMS

To investigate the underlying mechanism of PD-induced GI dysmotility in MPTP (1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine)-induced animal model.

METHODS

C57BL/6 mice were administered with or without a selective dopamine neurotoxin, MPTP, to induce parkinsonian symptoms. In addition to in vivo studies, in vitro experiments were also conducted in colon specimens using l-methyl-4-phenylpyridinium (MPP+), a metabolic product of MPTP. Gastric emptying, colon motility, nitrergic relaxation, and western blot experiments were performed as reported.

RESULTS

MPTP-induced PD mice showed decreased expression of nuclear factor erythroid 2-related factor (Nrf2) and its target phase II genes in gastric and colon neuromuscular tissues. Decreased levels of tetrahydrobiopterin (BH4, a critical cofactor for nNOS dimerization) associated with uncoupling of nNOS in gastric and colon tissues exposed to MPTP. Impaired enteric nitrergic system led to delayed gastric emptying and slower colonic motility compared to the control mice. In vitro results in colon specimens confirm that activation of Nrf2 restored MPP+-induced suppression of alpha-synuclein, tyrosine hydroxylase (TH), Nrf2, and heme oxygenase-1. In vitro exposure to L-NAME [N(w)-nitro-L-arginine methyl ester], a NOS synthase inhibitor, reduced protein expression of TH in colon tissue homogenates.

CONCLUSIONS

Loss of Nrf2/BH4/nNOS expression in PD impairs antioxidant gene expression, which deregulates NO synthesis, thereby contributing to the development of GI dysmotility and constipation. Nitric oxide appears to be important to maintain dopamine synthesis in the colon.

The effect of naringenin on the role of nuclear factor (erythroid-derived 2)-like2 (Nrf2) and haem oxygenase 1 (HO-1) in reducing the risk of oxidative stress-related radiotoxicity in the spleen of rats

The present study was to evaluate the radiomitigative effect of naringenin (NRG) on the modulation of ionizing radiation (IR)-induced spleen injury. Rats were exposed to 12 Gy (3Gy/two times/week). NRG (50mg/Kg), was orally given one hour after the first radiation dose, and daily continued during the irradiation period. Rats were sacrificed 1 day after the last dose of radiation. NRG showed a significant decrease of malondialdehyde, hydrogen peroxide with a significant elevation of superoxide dismutase, catalase and glutathione peroxidase activities and glutathione content. Moreover, NRG confirmed the intracellular defense mechanisms through activation of nuclear factor (erythroid-derived 2)-like2 (Nrf2) and haem oxygenase-1 (HO-1) levels and their protein expression. In addition, NRG deactivated the nuclear factor-κB (NF-κB) and reduced the pro-inflammatory cytokines. Further, NRG showed positive modulation in the haematological values (WBCs, RBCs, Hb, Hct% and PLt). In conclusion, these results suggested that NRG reversed the IR-induced redox-imbalance in the rat spleen.

Soursop fruit extract mitigates scopolamine-induced amnesia and oxidative stress via activating cholinergic and Nrf2/HO-1 pathways

Current therapeutic interventions for memory loss are inadequate and are associated with numerous adverse effects. There is an urgent need for new alternative agents for the treatment of memory loss and related disorders. Here, we investigated the potential neuroprotective role of soursop fruit extract (SSFE) in scopolamine (SCO)-induced amnesia and oxidative damage in the hippocampus of rats. Thirty-five rats were randomly allocated into 5 groups: control, SCO, SSFE, SCO, SSFE+SCO and N-acetylcysteine (NAC) + SCO. SCO-treatment increased acetylcholine esterase activity and decreased hippocampal levels of acetylcholine, serotonin, dopamine, norepinephrine, and histamine. The level of ATP increased. SCO-treated rats showed a disturbance in oxidative status, which was evident through the increase in malondialdehyde, and nitrites/nitrates and a decrease in cellular antioxidant molecules including glutathione, superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase. A disturbance was also observed via downregulation of the nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 defense pathways. SCO-treatment enhances a neuroinflammatory state, as indicated by the release of tumor necrosis factor- α and interleukin-1β and increased inducible nitric oxide synthase and mRNA expression. SCO-treatment decreased the expression of the anti-apoptotic protein, B cell lymphoma 2 and increased the expression of the pro-apoptotic protein, Bcl-2 associated X protein, caspase-3 and cytochrome c in hippocampal neurons. SSFE pretreatment markedly ameliorated hippocampal changes. Our findings revealed that SSFE exerts its potential anti-amnestic effect mainly through the activation of the cholinergic system and Nrf2/HO-1 pathway.

5-aminolaevulinic acid (ALA), enhances heme oxygenase (HO)-1 expression and attenuates tubulointerstitial fibrosis and renal apoptosis in chronic cyclosporine nephropathy

BACKGROUND

Cyclosporine-A (CsA) is an immunosuppressant indicated for various immunological diseases; however, it can induce chronic kidney injury. Oxidative stress and apoptosis play a crucial role in CsA-induced nephrotoxicity. The present study evaluated the protective effect of combining 5-aminolaevulinic acid with iron (5-ALA/SFC), a precursor of heme synthesis, to enhance HO-1 activity against CsA-induced chronic nephrotoxicity.

METHODS

Mice were divided into three groups: the control group (using olive oil as a vehicle), CsA-only group, and CsA+5-ALA/SFC group. After 28 days, the mice were sacrificed, and blood and kidney samples were collected. In addition to histological and biochemical examination, the mRNA expression of proinflammatory and profibrotic cytokines was assessed.

RESULTS

Renal function in the 5-ALA/SFC treatment group as assessed by the serum creatinine and serum urea nitrogen levels was superior to that of the CsA-only treatment group, demonstrating that 5-ALA/SFC significantly attenuated CsA-induced kidney tissue inflammation, fibrosis, apoptosis, and tubular atrophy, as well as reducing the mRNA level of TNF-α, IL-6, TGF-β1, and iNOS while increasing HO-1.

CONCLUSION

The activity of 5-ALA/SFC has important implications for clarifying the mechanism of HO-1 activity in CsA-induced nephrotoxicity and may provide a favorable basis for clinical therapy.

Schisandrin C enhances odontoblastic differentiation through autophagy and mitochondrial biogenesis in human dental pulp cells

OBJECTIVE

To investigate the role of Schisandrin C in odontoblastic differentiation, and its relations between autophagy and mitochondrial biogenesis in human dental pulp cells (HPDCs).

DESIGN

Fresh third molars were used, and cultured for HDPCs. Western blotting technique, Alizarin red S staining, alkaline phosphatase (ALP) activity, and confocal microscopy were used to detect autophagy, mitochondrial biogenesis, and odontoblastic differentiation. To understand the mechanism of Schisandrin C, the HDPCs were treated with lipopolysaccharide (LPS), autophagy and heme oxygenase-1 (HO-1) inhibitors: 3-Methyladenine (3-MA) and Zinc protoporphyrin IX (ZnPP), respectively.

RESULTS

LPS decreased the expression of autophagy molecules [autophagy protein 5 (ATG-5), beclin-1, and microtubule-associated protein 1A/1B light chain 3 (LC3-I/II)] and mitochondrial biogenesis molecules [heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)], and disrupted odontoblastic differentiation. The down-regulation of autophagy and mitochondrial biogenesis with 3-MA and ZnPP inhibited odontoblastic differentiation. However, Schisandrin C restored the expression of all the above molecules, even with LPS and inhibitor treatment. This result demonstrates that autophagy and mitochondrial biogenesis plays an essential role in odontoblastic differentiation, and Schisandrin C activates these systems to promote odontoblastic differentiation of HDPCs.

CONCLUSION

Schisandrin C has potential characters to regulate odontoblastic differentiation, and may be recommended for use as a compound for pulp homeostasis.

Structural requirements of flavonoids to induce heme oxygenase-1 expression

Population studies suggest cardiovascular health benefits of consuming fruits and vegetables rich in polyphenolic compounds such as flavonoids. We reported previously that the flavonoid quercetin protects arteries from oxidant-induced endothelial dysfunction and attenuates atherosclerosis in apolipoprotein E gene knockout mice, with induction of heme oxygenase-1 (Hmox1) playing a critical role. The present study investigated the structural requirements of flavonoids to induce Hmox1 in human aortic endothelial cells (HAEC). We identified ortho-dihydroxyl groups and an α,β-unsaturated system attached to a catechol as the key structural requirements for Hmox1 induction. Active but not inactive flavonoids had a low oxidation potential and prevented ascorbate autoxidation, suggesting that Hmox1 inducers readily undergo oxidation and that oxidized, rather than reduced, flavonoids may be the biological inducer of Hmox1. To test this hypothesis, we synthesized stable derivatives of caffeic acid (3-(3,4-dihyroxyphenyl)-2-propenoic acid) containing either ortho-dihydroxy or ortho-dioxo groups. Compared with the dihydroxy compound, the quinone analog induced Hmox1 more potently in HAEC and also provided enhanced protection to arteries of wild type animals against oxidant-induced endothelial dysfunction. In contrast, the quinone analog failed to provide protection against oxidant-induced endothelial dysfunction in arteries of Hmox1^-/- mice, establishing a key role for Hmox1 in vascular protection. These results suggest that oxidized forms of dietary polyphenols are the likely inducers of Hmox1 and may explain in part the protective cardiovascular effects of diets rich in these compounds.

Resveratrol Attenuates the Cytotoxicity Induced by Amyloid-β1-42 in PC12 Cells by Upregulating Heme Oxygenase-1 via the PI3K/Akt/Nrf2 Pathway

Oxidative stress and cytotoxic damage induced by amyloid beta (Aβ) have been considered pivotal in the pathogenesis of Alzheimer's disease (AD) and may represent a target for treatment. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway elicits a survival signal to protect against multiple injuries, and the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), a downstream target of the PI3K/Akt pathway, can bind to HO-1. Resveratrol, a natural polyphenol derived from grapes, has been widely reported to have diverse antioxidative effects against AD, but the mechanisms have not been fully elucidated. The present study aims to investigate the effects of resveratrol on Aβ_1-42-induced cytotoxicity in PC12 cells and to explore the potential mechanisms of these effects. PC12 cells were cultured and treated with Aβ_1-42. Oxidative stress was assessed by measuring malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) levels. After treating with resveratrol at different concentrations (0, 10, 20, 40 μM) and for different durations (24, 48, 72 h), the generation of MDA, GSH, and SOD were detected; cell viability was assessed by MTT assay. The production of reactive oxygen species (ROS) was determined using an ROS Assay Kit. Western blotting was used to detect the protein expression. Our studies showed that pretreatment with resveratrol could reduce Aβ_1-42-induced oxidative stress in PC12 cells by inhibiting the generation of MDA and ROS and increasing the production of SOD and GSH. Resveratrol markedly attenuated the Aβ_1-42-induced loss in cell viability in PC12 cells in both a dose- and time-dependent manner. More importantly, resveratrol stimulated the activation of HO-1, Nrf2, PI3K, and phosphorylated Akt. Notably, the neuroprotective effects of resveratrol were eliminated by the HO-1 inhibitor zinc protoporphyrin IX (ZnPP), Nrf2 small interfering RNA (siRNA), and the PI3K/Akt inhibitor LY294002. Taken together, the findings suggest that the cytoprotection of resveratrol against the cytotoxicity induced by Aβ_1-42 in PC12 cells is through the upregulation of HO-1 expression via the activation of the PI3K/AKT/Nrf2 intracellular signaling pathway, which might provide novel insights for understanding the mechanism of the neuroprotective effect of resveratrol as an anti-AD drug.

Peanut sprout extract attenuates cisplatin-induced ototoxicity by induction of the Akt/Nrf2-mediated redox pathway

OBJECTIVE

Cisplatin is commonly used to treat solid tumors. However, permanent hearing loss is a major side effect of cisplatin chemotherapy and often results in dose reduction of the cisplatin chemotherapy. Peanut sprouts show cytoprotective properties owing to their antioxidant activities. This study was designed to investigate the effect of peanut sprout extract (PSE) on cisplatin-induced ototoxicity in an auditory cell line, HEI-OC1 cells.

METHODS

Cells were exposed to cisplatin for 24 h, with or without pre-treatment with PSE, cell viability was examined using the MTT assay. Apoptotic cells were identified by double staining with Hoechst 33258 and propidium iodide. Western blot analysis was performed to examine apoptotic proteins including C-PARP and C-caspase, anti-apoptotic protein Bcl-2, and Nrf2 redox system activation. Mitochondrial reactive oxygen species (ROS) were investigated to examine whether PSE could scavenge cisplatin-induced ROS. Real-time PCR analyses were performed to investigate the mRNA levels of antioxidant enzymes including NQO1, HO-1, GPx2, Gclc, and catalase.

RESULTS

The cisplatin-treated group showed reduced cell viability, increased apoptotic properties and markers, and increased ROS levels. PSE pre-treatment before cisplatin exposure significantly increased cell viability and reduced apoptotic properties and ROS production. These effects resulted from the up-regulation of antioxidant genes, including NQO1, HO-1, GPx2, Gclc, and catalase through Akt phosphorylation and Nrf2 activation.

CONCLUSION

Our results demonstrate that PSE protects from cisplatin-induced cytotoxicity by activating the antioxidant effects via the Akt/Nrf-2 pathway in this auditory cell line, and indicate that PSE may provide novel treatment to prevent cisplatin-induced ototoxicity.

[Protective effect of proanthocyanidin on oxidative stress and mRNA expression of Nrf2 and HO-1 of mice cerebellar tissue induced by cypermethrin]

OBJECTIVE

To investigate the protective effect of proanthocyanidin on oxidative stress and mRNA expression of Nrf2 and HO-1 of mice cerebellar tissue induced by cypermethrin.

METHODS

A total of 50 male Kunming mice were randomly divided into five groups by gavage once daily for three consecutive weeks, the control group, CYP group( 10 mg / kg) and PC pretreated group( 50, 100 and 200 mg / kg). The mice were sacrificed and activitie levels of GSH-Px, T-SOD, CAT and MDA were measured, and then used the immunohistochemistry to analyse the expression of Nrf2, semi-quantitative RTPCR detected mRNA expression of Nrf2 and HO-1.

RESULTS

Compared to the controlgroup, the activity levels of GSH-Px, T-SOD, CAT decreased and MDA increased in CYP group. Nucleus positive cells was higher and mRNA expression of Nrf2 and HO-1 was higher than the control group( P < 0. 05). Compared to the CYP group, the level of GSHPx、T-SOD、CAT increased and MDA decreased in PC pretreated group, the count of nucleus-positive cells and mRNA expression of Nrf2 and HO-1 was lower than the CYP group( P < 0. 05).

CONCLUSION

s Cypermethrin could increase oxidative stress in cerebellar tissue of mice, induces the nuclear translocation of Nrf2 from the cytoplasm to the nucleus, and upregulating downstream gene of HO-1 expression. Proanthocyanidin could adjust mRNA expression of Nrf2 and HO-1 and ameliorate cypermethrin-induced oxidative stress.

Marine-Derived Secondary Metabolite, Griseusrazin A, Suppresses Inflammation through Heme Oxygenase-1 Induction in Activated RAW264.7 Macrophages

A new secondary metabolite, named griseusrazin A (1), was isolated from the marine-derived bacterium Streptomyces griseus subsp. griseus. The structure of the compound was determined by analysis of spectroscopic data including MS, COSY, HSQC, HMBC, and (15)N-HMBC data. Griseusrazin A (1) inhibited the production of inflammatory mediators, such as prostaglandin E2 and nitric oxide, which was mediated through the suppression of the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The production of pro-inflammatory cytokines, such as interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α, in the LPS-stimulated cells was also effectively blocked by griseusrazin A (1). Furthermore, this anti-inflammatory activity of 1 was linked to its inhibitory effects against the nuclear translocation of NF-κB p50 and p65, as wells as NF-κB binding activity. In the further study to elucidate the anti-inflammatory mechanism, 1 was shown to induce heme oxygenase-1 (HO-1) expression through the enhancement of nuclear translocation of nuclear factor E2-related factor 2. Furthermore, the anti-inflammatory activity of 1 in the LPS-stimulated cells was partially reversed by an HO inhibitor, tin protoporphyrin. These results indicate that the anti-inflammatory effect of 1 is associated with Nrf2-mediated HO-1 expression.

Vascular and metabolic effects of the haem oxygenase-1 inducer haem arginate in subjects with the metabolic syndrome: A translational cross-over study

This translational randomized and vehicle-controlled cross-over study was performed to assess the impact of haem arginate treatment on haem oxygenase-1 induction, endothelial function and insulin sensitivity in subjects with the metabolic syndrome (n = 14). Both treatment periods consisted of 5 days. Haem arginate or vehicle (l-arginine) was administered intravenously on Days 1 and 3. Forearm blood flow in response to acetylcholine and nitroglycerine was measured by venous occlusion plethysmography (Day 3), insulin sensitivity by a hyperinsulinaemic clamp procedure (Day 5). Haem arginate did not improve endothelial function or insulin sensitivity but significantly reduced the vasodilator response to nitroglycerine (p < 0.01). These negative findings are in contrast to the preclinical data, which may be due to short duration of therapy and limited haem oxygenase-1 induction as well as interference by markedly elevated plasma haem levels observed after haem arginate treatment (p < 0.01). Future studies should pay attention to the delicate balance between sufficient dosing and timely normalization of plasma haem levels.

Autophagy Deficiency Diminishes Indomethacin-Induced Intestinal Epithelial Cell Damage through Activation of the ERK/Nrf2/HO-1 Pathway

Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause epithelial cell damage in the stomach, intestine, and colon. NSAIDs are reported to induce autophagy and apoptosis in intestinal epithelial cells; however, their role in cell damage is poorly understood. To examine the role of autophagy in cell damage, we used autophagy-related gene Atg5-conditional knockout mice, in which the Atg5 gene is only knocked out in intestinal epithelial cells. In an indomethacin (IM)-induced gastrointestinal ulcer mouse model, intestinal epithelium damage was reduced in Atg5-conditional knockout mice compared with wild-type mice. IM-induced damage in IEC6 rat intestinal epithelial cells was reduced when Atg5 was silenced (IEC6shAtg5 cells). Western blot analyses indicated that IM-induced apoptosis decreased, and the potent, oxidative stress-related extracellular signal-regulated kinase (ERK)/nuclear factor-erythroid2-like2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway was upregulated in IEC6shAtg5 cells. An experiment using a reactive oxygen species (ROS)-sensitive fluorescent dye in IEC6shAtg5 cells revealed that the amount of ROS at the baseline and the rate of increase after IM treatment were lower than in intact IEC6 cells. The mitochondrial membrane potential at the baseline and the reduction rate in IM-treated IEC6shAtg5 cells were lower than in intact IEC6 cells, indicating that autophagy deficiency increased ROS production caused by mitochondrial disturbance. Furthermore, MnTMPyP, a manganese-superoxide dismutase mimetic, significantly inhibited IM-induced autophagy and subsequent apoptosis as well as activation of the ERK/Nrf2/HO-1 pathway. These data suggest that autophagy deficiency and subsequent activation of the ERK/Nrf2/HO-1 pathway diminished IM-induced, apoptosis-mediated intestinal epithelial cell damage, and genetic analyses of single nucleotide polymorphisms in autophagy-related genes could predict NSAID-induced intestinal injury.

Phorbaketal A, Isolated from the Marine Sponge Phorbas sp., Exerts Its Anti-Inflammatory Effects via NF-κB Inhibition and Heme Oxygenase-1 Activation in Lipopolysaccharide-Stimulated Macrophages

Marine sponges harbor a range of biologically active compounds. Phorbaketal A is a tricyclic sesterterpenoid isolated from the marine sponge Phorbas sp.; however, little is known about its biological activities and associated molecular mechanisms. In this study, we examined the anti-inflammatory effects and underlying molecular mechanism of phorbaketal A in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We found that phorbaketal A significantly inhibited the LPS-induced production of nitric oxide (NO), but not prostaglandin E₂, in RAW 264.7 cells. Further, phorbaketal A suppressed the expression of inducible NO synthase at both the mRNA and protein levels. In addition, phorbaketal A reduced the LPS-induced production of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and monocyte chemotactic protein-1. Treatment with phorbaketal A inhibited the transcriptional activity of nuclear factor-kappaB (NF-κB), a crucial signaling molecule in inflammation. Moreover, phorbaketal A up-regulated the expression of heme oxygenase-1 (HO-1) in LPS-stimulated RAW 264.7 cells. These data suggest that phorbaketal A, isolated from the marine sponge Phorbas sp., inhibits the production of inflammatory mediators via down-regulation of the NF-κB pathway and up-regulation of the HO-1 pathway.

Antioxidant Activity and Induction of mRNA Expressions of Antioxidant Enzymes in HEK-293 Cells of Moringa oleifera Leaf Extract

The leaves of Moringa oleifera, collected in different provinces in Thailand, were determined for the contents of total phenolics, total flavonoids, major components, and antioxidant activity. The extract and its major active components were investigated for the inhibition of H2O2-induced reactive oxygen species production and the effects on antioxidant enzymes mRNA expression. The extract, crypto-chlorogenic acid, isoquercetin and astragalin, significantly reduced the reactive oxygen species production inducing by H2O2 in HEK-293 cells. Treatment with isoquercetin significantly increased the mRNA expression levels of antioxidant enzymes such as superoxide dismutase, catalase and heme oxygenase 1. These results confirm that M. oleifera leaves are good sources of natural antioxidant with isoquercetin as an active compound.

The effect of 17β-estradiol on the expression of dipeptidyl peptidase III and heme oxygenase 1 in liver of CBA/H mice

BACKGROUND

17β-estradiol (E₂) has well-established cardioprotective, antioxidant and neuroprotective role, and exerts a vast range of biological effects in both sexes. Dipeptidyl peptidase III (DPP III) is protease involved as activator in Keap1-Nrf2 signalling pathway, which is important in cellular defense to oxidative and electrophilic stress. It is generally accepted that oxidative stress is crucial in promoting liver diseases.

OBJECTIVE

To examine the effect of E₂ on the expression of DPP III and haeme oxygenase 1 (HO-1) in liver of adult CBA/H mice of both sexes.

METHODS

Gene and protein expressions of studied enzymes were determined by quantitative real-time PCR and Western blot analysis. Immunohistochemistry was performed to analyse the localization of both proteins in different liver cell types.

RESULTS

Ovariectomy diminished expression of DPP III and HO-1 proteins. E₂ administration abolished this effect, and even increased these proteins above the control. A significant enhancement in DPP III protein was found in E₂-treated males, as well. A decrease in the expression of HO-1, but not of the DPP III gene, was detected in the liver of ovariectomized females. HO-1 protein was found localized in the pericentral areas of hepatic lobules (Kupffer cells and hepatocytes), whilst DPP III showed a uniform distribution within hepatic tissue.

CONCLUSIONS

We demonstrate for the first time that E₂ influences the protein level of DPP III in vivo, and confirm earlier finding on HO-1 gene upregulation by 17β-estradiol. These results additionally confer new insights into complexity of protective action of E₂.

3,4-dihydroxyphenylethanol suppresses irradiation-induced pulmonary fibrosis in adult rats

The present study demonstrates the effect of DHPEA on suppression of irradiation-induced pulmonary fibrosis. A (60)Co irradiator was used to induce pulmonary fibrosis in a rat model at a dose of 22 Gy. The rats of the treatment and positive control group were intraperitoneally injected DHPEA (10 mg/kg) or dexamethasone (DEX; 5 mg/kg) daily for 30 days. Hydroxyproline assay was used to evaluate the fibrosis of pulmonary and lung tissue sections after irradiation. Hematoxylin and eosin (H&E) and Masson's trichrome stained lung section were used for alveolitis and fibrosis score analyses, respectively. Immunohistochemistry was used for surfactant protein-B (SPB) and α-SMA expression analysis. Western blot analysis was employed for analysis of nuclear transcription factor NF-E2-related factor 2 (Nrf-2) and its associated antioxidant enzymes like heme oxygenase-1 (HO-1) and NAD (P) H: quinone oxidoreductase-1 (NQO-1). Results revealed a significant decrease in mortality rates and lung index scores, decreased collagen deposition, reduced MDA content and enhanced superoxide dismutase (SOD) activity in DHPEA treated rats compared to DEX-treated rats. DHPEA treatment also inhibited (myo) fibroblast proliferation, and regulated serum levels of TGF-β1, IL-6, IL-10, and TNF-α. In addition, DHPEA-treatment activated Nrf-2 and its downstream antioxidant enzymes HO-1 and NQO-1. Thus DHPEA can be a promising agent for the suppression of irradiation-induced pulmonary fibrosis.

Effects of Cymbopogon citratus Stapf water extract on rat antioxidant defense system

BACKGROUND

Cymbopogon citratus, Stapf(CCS) is commonly known as lemon grass. Previous studies showed that it has a strong antioxidant property and have been traditionally used as analgesic, antipyretic, antiseptic in SoutheastAsia. However, the effect of CCS on antioxidant defense system has not been demonstrated.

OBJECTIVE

The present study was conducted to investigate the effects of CCS water extract on rat antioxidant defense system, especially on the expression of y-glutamylcysteine ligase (γ-GCL) and heme oxygenase-1 (HO-1).

MATERIAL AND METHOD

The CCS water extract was screenedfor its phytochemical contents and antioxidant activity in vitro. Moreover, the extract was studied in rats to evaluate its effects in vivo. Male Sprague-Dawley rats aged eight weeks (250±20 g) were orally administered with CCS at 250, 500 and 1,000 mg/kg/day for one month.

RESULTS

The extract contained flavonoids (496.17 mg gallic acid/g CCS extract) and phenolic compounds (4,020.18 mg catechin/g CCS extract). The scavenging activity (DPPH assay) of the extract was demonstrated by EC50 of 917.76±86.89 μg/ ml whereas the EC50 of the potent antioxidant, vitamin C was 31.22±1.84 μg/ml. In the animals, the protein expression of antioxidant enzymes, γGCL and HO-1 was significantly increased in the high dose-treated animals (1,000 mg/kg/day). This was consistent with elevation ofserum total antioxidant capacity.

CONCLUSION

Taken together the present study provides evidence that CCS water extract exhibits antioxidant activity and antioxidant enzymes induction in vivo.

The effect of induction of endogenous CO by heme-oxygenase inducer, hemin versus heme-oxygenase blocker, zinc mesoporphyrin on gastric secretion and ulceration under different conditions in adult male albino rats

Although its role and importance is less well studied, carbon monoxide (CO) has been identified as the second gasotransmitter in the GI tract. This study was performed to investigate the effect of modifying the endogenous CO production by altering heme oxygenase (HO) activity either by induction through hemin administration or inhibition by zinc mesoporphyrin administration on gastric secretion and ulceration induced by either cold restraint stress (CRS) or indomethacin (IND) treatment in adult male albino rats. Our results revealed that hemin significantly increased HO-1 levels with an increase in carboxyhemoglobin (COHb) level while zinc mesoporphyrin significantly decreased HO-1 levels with a decrease in COHb level in all groups. Hemin pretreatment significantly attenuated the gastric mucosal lesions induced by CRS and IND administration, which was accompanied by significant reduction in free and total acidity of gastric secretion, decreased proteolytic activity and marked attenuation of lipid peroxidation inspite of decreased NO and PGE2 levels. On the other hand, Inhibition of HO-1 activity by zinc mesoporphyrin prevented most of the effects caused by hemin administration except for its similar reduction in gastric mucosal NO and PGE2 levels. On conclusion, Hemin exerts a protective effect against CRS and IND-induced gastric ulcers possibly via inducing HO-1 and increasing endogenous production of CO (Tab. 2, Fig. 4, Ref. 75).

Platycodon grandiflorum root-derived saponins attenuate atopic dermatitis-like skin lesions via suppression of NF-κB and STAT1 and activation of Nrf2/ARE-mediated heme oxygenase-1

PURPOSE

The consequences of precipitously rising allergic skin inflammation rates worldwide have accelerated the risk of atopic dermatitis (AD). Natural product-based agents with good efficacy and low risk of side effects offer promising prevention and treatment strategies for inflammation-related diseases. We have already reported that Platycodon grandiflorum root-derived saponins (Changkil saponins, CKS) have many pharmacological effects, including anti-inflammatory and anti-allergic effects, but its influence on AD remains unclear. Therefore, we evaluated the inhibitory effect of CKS, mainly platycodin D, on AD-like skin symptoms in mice and the possible mechanisms in cells.

METHODS

Mice were sensitized and challenged with 2,4-dinitrochlorobenzene (DNCB). Four weeks after challenge, mice were treated with oral administration of CKS for 4 weeks. In addition, cells were used to evaluate the effect of CKS, mainly platycodin D, on the TARC expression regulated mechanism.

RESULTS

CKS attenuated DNCB-induced dermatitis severity, serum levels of IgE and TARC, and mRNA expression of TARC, TNF-α, IFN-γ, IL-4, IL-5, and IL-13 in mice. Histopathological examination showed reduced thickness of the epidermis/dermis and dermal infiltration of inflammatory cells and mast cells in the ears. Moreover, CKS and platycodin D inhibited TNF-α/IFN-γ-induced TARC expression through the suppression of NF-κB and STAT1 and induction of Nrf2/ARE-mediated hemeoxygenase-1 (HO-1) expression in cells.

CONCLUSION

We suggest that CKS and platycodin D inhibited the development of AD-like skin symptoms by regulating cytokine mediators and may be an effective alternative therapy for AD-like skin symptoms.

Oleuropein and oleacein may restore biological functions of endothelial progenitor cells impaired by angiotensin II via activation of Nrf2/heme oxygenase-1 pathway

Endothelial progenitor cells (EPCs) are responsible for neovascularization of ischaemic tissue and may participate in re-endothelization of an injured arterial wall. There is evidence that angiotensin II, by an increase of gp91phox expression and induction of ROS generation, accelerates cell senescence and impairs functions of EPCs. Oleacein is a main phenolic compound from olive oil, whereas oleuropein is present in olive leaves. Both compounds possess antioxidative, hypotensive and anti-inflammatory properties and show beneficial activity on the cardiovascular system. In this study, we examined whether oleoeuropein and oleacein could protect EPCs against impairment of their functions due to angiotensin-induced cell senescence. CD31(+)/VEGFR-2(+) cells were isolated from young healthy volunteers blood samples and cultured on fibronectin-coated plates with angiotensin (1.0μM) in presence or absence of increasing concentrations (from 1.0 to 10.0 μM) of oleoeuropein or oleacein. As compared to angiotensin II-treated cells, EPCs exposed to oleacein or oleuropein prior to angiotensin II showed a significant increase of proliferation and telomerase activity, and a decrease in the percentage of senescent cells and intracellular ROS formation. Oleacein and oleuropein restored migration, adhesion and tube formation of EPCs diminished by angiotensin II in a concentration-dependent manner. This effect was related to NF-E2-related factor 2 (Nrf2) transcription factor activation and the increase of heme oxygenase-1 (HO-1) expression.

Neohesperidin attenuates cerebral ischemia-reperfusion injury via inhibiting the apoptotic pathway and activating the Akt/Nrf2/HO-1 pathway

Oxidative stress is well known to play a pivotal role in cerebral ischemia-reperfusion injury. On the basis of this fact, antioxidative agents have been demonstrated to be neuroprotective. Neohesperidin (NH) is abundant in citrus flavonoids and possesses reactive oxygen species scavenging activity and neuroprotective effects in vitro. However, little is known about its effects on cerebral ischemia-reperfusion injury and the underlying mechanisms. In this study, we use a rat model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of NH. NH significantly improved neurological functions and attenuated MCAO-induced infarct volume, pathological changes, and neuronal loss. Moreover, it enhanced antioxidant capacity and suppressed oxidative stress in the brain. NH inhibited the MCAO-induced upregulation of Bax, cytochrome c, and cleaved caspase-9 and -3, as well as the downregulation of Bcl-2. Interestingly, NH treatment upregulated heme oxygenase-1 (HO-1) in a concentration-dependent manner, which was due to the NH-mediated activation of the protein kinase B (Akt)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. NH also abolished the MCAO-induced inhibition of the Akt/Nrf2 pathway. In conclusion, NH attenuates cerebral ischemia-reperfusion injury via the inhibition of neuronal apoptosis and oxidative stress through the regulation of the apoptotic pathway and the Akt/Nrf2/HO-1 pathway. NH might be a promising preventive agent for ischemic stroke.

Quercetin suppressed CYP2E1-dependent ethanol hepatotoxicity via depleting heme pool and releasing CO

Naturally occuring quercetin protects hepatocytes from ethanol-induced oxidative stress, and heme oxygenase-1 (HO-1) induction and carbon monoxide (CO) metabolite may be implicated in the beneficial effect. However, the precise mechanism by which quercetin counteracts CYP2E1-mediated ethanol hepatotoxicity through HO-1 system is still remained unclear. To explore the potential mechanism, herein, ethanol (4.0 g/kg.bw.) was administrated to rats for 90 days. Our data showed that chronic ethanol over-activated CYP2E1 but suppressed HO-1 with concurrent hepatic oxidative damage, which was partially normalized by quercetin (100mg/kg.bw.). Quercetin (100 μM) induced HO-1 and depleted heme pool when incubated to human hepatocytes. Ethanol-stimulated (100mM) CYP2E1 upregulation was suppressed by quercetin but further enhanced by HO-1 inhibition with resultant heme accumulation. CO scavenging blocked the suppression of quercetin only on CYP2E1 activity. CO donor dose-dependently inactivated CYP2E1 of ethanol-incubated microsome, which was mimicked by HO-1 substrate but abolished by CO scavenger. Thus, CYP2E1-mediated ethanol hepatotoxicity was alleviated by quercetin through HO-1 induction. Depleted heme pool and CO releasing limited protein synthesis and inhibited enzymatic activity of CYP2E1, respectively.

Dobutamine-mediated heme oxygenase-1 induction via PI3K and p38 MAPK inhibits high mobility group box 1 protein release and attenuates rat myocardial ischemia/reperfusion injury in vivo

BACKGROUND

It has been reported that the induction of heme oxygenase-1 (HO-1) mediated by β1-adrenergic receptor inhibits high mobility group box 1 protein (HMGB1) release and increases the survival rate in cecal ligation and puncture-induced septic mice. The present study aimed to investigate whether dobutamine, a selective β1-adrenergic receptor agonist, could inhibit HMGB1 release via β1-adrenergic receptor-mediated HO-1 induction and attenuate myocardial ischemia/reperfusion (I/R) injury in rats.

MATERIALS AND METHODS

Anesthetized male rats were pretreated with dobutamine (5 or 10 μg. Kg-1. min-1, intravenous) before ischemia in the absence and/or presence of LY294002 (0.3 mg/Kg), a phosphatidylinositol 3-kinase (PI3K)< inhibitor; SB203580 (1 mg/Kg), a p38 mitogen-activated-protein kinase (P38 mitogen-activated-protein kinase [p38 MAPK]) inhibitor, and zinc protoporphyrin IX ([ZnPPIX], 10 mg/Kg), a HO-1 inhibitor, respectively, and then subjected to ischemia for 30 min followed by reperfusion for 4 h. The myocardial I/R injury and oxidative stress were assessed. Likewise, the expressions of HO-1 protein, nuclear factor kappa B (NF-κB) p65, and HMGB1 were measured by Western blot analysis.

RESULTS

Dobutamine significantly and dose-dependently attenuated myocardial I/R injury, reduced oxidative stress, and caused the induction of HO-1, the reduction of NF-κB activation and HMGB1 over expression. However, all the effects caused by dobutamine were significantly reversed by the presence of LY294002, SB203580, and ZnPPIX, respectively.

CONCLUSIONS

The present study demonstrated that dobutamine mediated the induction of HO-1 by selectively stimulating β1-adrenergic receptor via PI3K and p38 MAPK, which inhibited HMGB1 release and attenuated rat myocardial I/R injury in vivo.

Bryonolic acid transcriptional control of anti-inflammatory and antioxidant genes in macrophages in vitro and in vivo

Bryonolic acid (BA) (1) is a naturally occurring triterpenoid with pleiotropic properties. This study characterizes the mechanisms mediating the anti-inflammatory and antioxidant activities of BA and validates the utility of BA as a tool to explore the relationships between triterpenoid structure and activity. BA reduces the inflammatory mediator NO by suppressing the expression of the inflammatory enzyme inducible nitric oxide synthase (iNOS) in LPS-activated RAW 264.7 macrophage cells. In addition, BA robustly induces the antioxidant protein heme oxygenase-1 (HO-1) in vitro and in vivo in an Nrf2-dependent manner. Further analyses of Nrf2 target genes reveal selectivity for the timing and level of gene induction by BA in treated macrophages with distinct patterns for Nrf2-regulated antioxidant genes. Additionally, the distinct expression profile of BA on Nrf2 target genes relative to oleanolic acid suggests the importance of the triterpenoid scaffold in dictating the pleiotropic effects exerted by these molecules.

Flavonoids from silkworm droppings and their promotional activities on heme oxygenase-1

A new flavane glucoside, 7,2'-dihydroxy-8-hydroxyethyl-4'-methoxyflavane-2'-O-β-d-glucopyranoside (3), along with three known flavonoids, 7,2'-dihydroxy-8-prenyl-4'-methoxyflavane (1), euchrenone a(7) (2), and 7,2'-dihydroxy-8-prenyl-4'-methoxy-2'-O-β-d-glucopyranosylflavane (4), was isolated from silkworm droppings. The structures of the compounds were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and optical rotational characteristics. The compounds isolated from silkworm droppings were evaluated for their effects on heme oxygenase-1 (HO-1) activity. Compounds 1 and 3 increased the expression of HO-1 in HepG2 cells. HO-1 is an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron, and biliverdin, all of which are involved in the suppression of inflammatory mediators.

A sesquiterpenol extract potently suppresses inflammation in macrophages and mice skin and prevents chronic liver damage in mice through JNK-dependent HO-1 expression

This study aimed to elucidate the anti-inflammatory and hepatoprotective bioactivities of a sesquiterpenol, (1S,6R)-2,7(14),10-bisabolatrien-1-ol-4-one (BSL), isolated from Cryptomeria japonica (Taxodiaceae) wood extract. BSL markedly suppressed TNF-α and IL-6 secretion, PGE(2) production, and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in lipopolysaccharide (LPS)-stimulated mouse macrophages. BSL also potently inhibited the 12-O-tetradecanoylphorbol-13-acetate (TPA) induced protein levels of nitrotyrosine and COX-2 in mouse skin with dermatitis. Conversely, the stress protein heme oxygenase-1 (HO-1) was found upregulated in the same BSL-treated macrophages, probably through activation of the JNK-dependent pathway. LPS-induced activation of NF-κB and mitogen-activated protein kinase signaling pathways, however, was not responsive to BSL treatment. A BSL-enriched extract (BSL-E; 10mg/kg) significantly prevented CCl(4)-induced chronic liver injury, lipid accumulation, and cell necrosis and inhibited aminotransferase activities and iNOS and COX-2 overexpression in mice liver tissues, an effect comparable with that of silymarin, a hepatoprotective drug.

Caffeic acid phenethyl ester inhibits PDGF-induced proliferation of vascular smooth muscle cells via activation of p38 MAPK, HIF-1α, and heme oxygenase-1

Hyperproliferation of vascular smooth muscle cells (VSMCs) is critically involved in the onset of atherosclerosis and restenosis. Although caffeic acid phenethyl ester (CAPE, 1), one of the main constituents of honeybee propolis, has been shown to exert a beneficial effect in models of vascular injury in vivo, detailed mechanistic investigations in vascular cells are scarce. This study has examined the antiproliferative activity of 1 in platelet-derived growth factor (PDGF)-stimulated primary rat aortic VSMCs and aimed to shed light on underlying molecular mechanisms. Compound 1 inhibited the proliferation of VSMCs upon exposure to PDGF in a dose-dependent manner by interfering with cell cycle progression from the G0/1- to the S-phase. Enhanced phosphorylation of p38 mitogen-activated protein kinase (MAPK) as well as stabilization of hypoxia-inducible factor (HIF)-1α and subsequent induction of heme oxygenase-1 (HO-1) could be identified as molecular events contributing to the observed growth arrest in PDGF-activated VSMCs upon exposure to 1.

Involvement of heme oxygenase-1 in the anti-inflammatory activity of Chrysanthemum boreale Makino extracts on the expression of inducible nitric oxide synthase in RAW264.7 macrophages

AIM OF THE STUDY

This study is to elucidate the involvement of anti-inflammatory heme oxygenase-1 (HO-1) in the inhibitory activity of a Chrysanthemum boreale Makino (CB) extract on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages.

MATERIALS AND METHODS

Cell viability and NO assay were performed. In addition, iNOS expression was detected by Western blotting and real-time PCR. HO-1 expression was also evaluated by Western blotting, and blocking HO-1 activity on NO production was performed.

RESULTS

The CB extract at the highest concentration (100 μg/ml) significantly inhibited NO production by approximately 90% and suppressed iNOS protein expression by approximately 84.8% compared to LPS-stimulated cells. Furthermore, the CB extract (100 μg/ml) inhibited iNOS mRNA expression in a concentration-dependant manner and suppressed iNOS mRNA expression by 94.8%. The CB extract induced the expression of HO-1 in a dose-dependent manner, and blocking HO-1 activity abolished the inhibitory effects of the CB extract. Moreover, the addition of carbon monoxide such as tricarbonyl dichlororuthenium (II) dimmer (RuCO), a byproduct derived from heme degradation, mimicked the inhibitory action of low concentrations of CB extract.

CONCLUSION

These results suggest that a CB extract has potent anti-inflammatory activity in RAW264.7 macrophages involving the induction of HO-1.

Ammonia and proinflammatory cytokines modify expression of genes coding for astrocytic proteins implicated in brain edema in acute liver failure

There is evidence to suggest that, in acute liver failure (ALF), brain ammonia and proinflammatory cytokines may act synergistically to cause brain edema and its complications (intracranial hypertension, brain herniation). However, the molecular mechanisms involved remain to be established. In order to address this issue, semi-quantitative RT-PCR was used to measure the expression of genes coding for astrocytic proteins with an established role in cell volume regulation in cerebral cortical astrocytes exposed to toxic agents previously identified in experimental and clinical ALF. Such agents include ammonia, the proinflammatory cytokine interleukin-1beta (IL-1beta) and combinations of the two. Exposure of cultured astrocytes to recombinant IL-1beta (but not ammonia) resulted in increased expression of aquaporin-4 (AQP-4). Both ammonia and proinflammatory mediators led to decreased expression of glial fibrillary acidic protein (GFAP), a cytoskeletal protein, but these effects were not additive. On the other hand, heme oxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) expression were significantly increased by exposure to both ammonia and proinflammatory mediators and although modest, these effects were additive suggestive of a synergistic mechanism. These findings suggest that worsening of brain edema and its complications in ALF due to proinflammatory mechanisms may result from exacerbation of oxidative stress-related mechanisms rather than upregulation of AQP-4 or decreases in expression of the astrocytic structural protein GFAP.

[Protective effect of heme oxygenase-1 induction in vivo to pancreas islet xenograft]

OBJECTIVE

To study the protective effect of islet xenograft and its possible mechanism of high expression of heme oxygenase-1 (HO-1) in donor pancreas islet induced by cobalt protoporphyrin (CoPP).

METHODS

Male SD rats and C57BL/6 mouse were used as donors and recipients respectively. Donors were divided into 3 groups according to different pretreatment 24 hours before donation: control group (injected intraperitoneally with NaCl), induce group [injected intraperitoneally with cobalt-protoporphyrin (CoPP)], block group (injected intraperitoneally with CoPP and zinc protoporphyrin simultaneously). A modified approach was used for islet isolation.Recipients were rendered diabetic by intraperitoneal injection of streptozotocin. Islets were transplanted into mouse subrenal capsule. Postoperative mouse glycemia were monitored daily and normoglycemia time was compared among each group. The receptor mouse serum IL-10 was detected by ELISA approach, and real-time PCR was used to check the expression of IL-10 mRNA in islet graft tissues. The graft tissues were observed for the lymphocyte infiltration after HE staining.

RESULTS

Diabetes mice accepted islets untreated, induced or blocked maintained the euglycemia for (9.3 +/- 1.4), (16.3 +/- 1.5) and (9.7 +/- 1.0) d respectively. The xeno-islets presented HO-1 over-expression survived much longer than that absent (P < 0.05), it was no significance between control group and block group (P > 0.05). The mouse islet serum IL-10 content after induction was (73.0 +/- 9.7) pg/ml, significantly higher than (30.6 +/- 3.9) pg/ml of the untreated group and (32.1 +/- 5.9) pg/ml of the blocked group (P < 0.05), there was no difference between control group and block group (P > 0.05). Moreover, the IL-10 mRNA expression up-regulated statistic significantly in HO-1 induced islet xeno-graft. Pathological examination showed that the graft lymphocyte infiltration of the induced group was obviously less serious than the other two groups.

CONCLUSIONS

The higher expression of HO-1 induced by CoPP in vivo would significantly prolong graft survival time and its mechanism could be related to immune modulation of IL-10.

Strategic targets to induce neovascularization by resveratrol in hypercholesterolemic rat myocardium: role of caveolin-1, endothelial nitric oxide synthase, hemeoxygenase-1, and vascular endothelial growth factor

Endothelial dysfunction and impaired angiogenesis constitute a hallmark of hypercholesterolemia. This study was designed to examine the effects of resveratrol, an antioxidant with lipid-lowering properties similar to those of statins, on neovascularization along with caveolar interaction with proangiogenic molecules in hypercholesterolemic rats. Animals were divided into: rats maintained on a normal diet (control group); rats maintained on a 5% high-cholesterol diet for 8 weeks (HC group); and rats maintained on a 5% high-cholesterol diet for 8 weeks and administered resveratrol (20 mg/kg) orally for 2 weeks (HCR group). Myocardial infarction was induced by ligating the left anterior descending artery. Herein we examined a novel method for stimulating myocardial angiogenesis by pharmacological preconditioning with resveratrol at both the capillary and arteriolar levels and the potential role of hemeoxygenase-1, endothelial nitric oxide synthase and caveolin-1 in mediating such a response. We also investigated the functional relevance of such treatment by assessing whether the induced neovascularization can help preserve left ventricle-contractile functional reserve in the setting of a chronic hypercholesterolemic condition. Four weeks after sham surgery and left anterior descending artery occlusion, rats underwent echocardiographic evaluation, which revealed improvement in ejection fraction and fractional shortening in the HCR group compared with the HC group. Left ventricular tissue sections displayed increased capillary and arteriolar density in the HCR group compared with the HC group. Western blot analysis revealed downregulation of vascular endothelial growth factor and hemeoxygenase-1 and increased association of caveolin-1 eNOS in the HC group, decreasing the availability of eNOS to the system; which was reversed with resveratrol treatment in the HCR group. This study was further validated in cardiac-specific hemeoxygenase-1-overexpressed mice assuming molecular cross-talk between the targets. Hence, our data identified potential regulators that primarily attenuate endothelial dysfunction by resveratrol therapy in hypercholesterolemic myocardium.

Sasim attenuates LPS-induced TNF-alpha production through the induction of HO-1 in THP-1 differentiated macrophage-like cells

AIM OF THE STUDY

Sasim, a traditional prescription composed of seven herbal mixtures, has been widely used as an oriental medicine for the treatment of cerebral infarction in Korea. However, the regulatory mechanisms by which the formula affects immune processing in cerebral infarction patients remain unknown.

MATERIALS AND METHODS

The levels of secretory protein of tumor necrosis factor (TNF)-alpha were determined in both THP-1 differentiated macrophage-like (THP-1/M) cells and Peripheral blood mononuclear cells (PBMCs) from cerebral infarction patients. Also, the levels of protein and mRNA of TNF-alpha and heme oxygenase-1 (HO-1) were detected in THP-1/M cells under our experimental condition.

RESULTS

Sasim markedly suppressed lipopolysaccharide (LPS)-induced TNF-alpha at the levels of secretory protein and mRNA in both PBMCs from cerebral infarction patients and THP-1/M cells. Interestingly, Sasim strongly induced HO-1, the rate-limiting enzyme of heme catabolism, at both the protein and mRNA levels in THP-1/M cells. Treatment with tin protoporphyrin IX (SnPP), an inhibitor of the catalytic activity of HO, significantly abolished the suppressive effect of Sasim on LPS-induced TNF-a production in THP-1/M cells.

CONCLUSIONS

These data indicate that Sasim may be beneficial in the cessation of inflammatory processes associated with cerebral infarction through the induction of HO-1 expression.

The protective effect of eupatilin on indomethacin-induced cell damage in cultured feline ileal smooth muscle cells: involvement of HO-1 and ERK

Chronic users of non-steroidal anti-inflammatory drugs frequently develop ulcerative lesions in their intestines. The purpose of the present study was to investigate whether eupatilin, an active ingredient derived from Artemisia plants, prevents this side effect in vitro. Extracts of the whole herb of Artemisia asiatica Nakai have been used in oriental medicine for the treatment of inflammation. As measured by the MTT assay, the treatment of cultured feline ileal smooth muscle cells (ISMCs) with 2.5mM indomethacin for 2h decreased the cell viability to 43%. Pretreatment with eupatilin resulted in dose-dependent inhibition on indomethacin-induced cell damage. This cytoprotective effect of eupatilin required concentrations of more than 150 microM and incubation periods of longer than 16 h. Pretreatment of ISMC with cycloheximide, an inhibitor of protein synthesis, attenuated the cytoprotective effect of eupatilin, suggesting that eupatilin induces proteins that are responsible for the cytoprotection. Heme oxygenase-1 (HO-1), which is known as a cytoprotective enzyme due to its anti-inflammatory actions, is a candidate protein since ZnPP, an HO-1 inhibitor, repressed the protective effect of eupatilin on indomethacin-induced cell damage in a concentration-dependent manner. Western blot analysis revealed that eupatilin-mediated HO-1 induction occurred in a concentration- and time-dependent manner. We also found that PD98059, a MEK (MAPK/ERK kinase) inhibitor, attenuated the eupatilin-induced HO-1 expression and nuclear translocation of transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). Taken together, the data imply that eupatilin protects ISMC from cell damage caused by indomethacin, and that its cytoprotective action could be attributed to eupatilin-mediated HO-1 induction via ERK and Nrf2 signaling in ISMC.

Upregulation of heme oxygenase-1 as a host mechanism for protection against nitric oxide-induced damage in human renal epithelial cells

OBJECTIVES

To examine whether urinary tract infection-associated stimuli could regulate heme oxygenase-1 (HO-1) expression and to asses the significance of HO-1 in protecting urinary tract epithelial cells against nitric oxide (NO)-induced damage.

METHODS

Heme oxygenase-1 expression was investigated in the human renal epithelial cell line A498 in response to the uropathogenic Escherichia coli (UPEC) strain IA2, the NO-donor DETA/NONOate (DETA/NO), and proinflammatory cytokines (interleukin-1beta, tumor necrosis factor-alpha, and interferon-gamma) using reverse transcriptase polymerase chain reaction and Western blot analysis. Cell viability was examined by the trypan blue exclusion test and light microscopy.

RESULTS

The HO-1 inducer hemin and DETA/NO increased HO-1 expression in A498 cells, and glutathione depletion further increased HO-1 expression in response to DETA/NO and hemin. Stimulation with a UPEC strain or cytokines did not upregulate HO-1 expression. The cytokines induced inducible NO synthase expression and caused an increase in nitrite production. Hemin significantly decreased cytokine-induced NO production (P <0.001). DETA/NO decreased the cell viability by approximately 75%, but hemin was able to attenuate DETA/NO-induced cell damage.

CONCLUSIONS

The expression of HO-1 increased in human renal epithelial cells in response to NO, and the expression was further enhanced in glutathione-depleted cells. The bacteria per se or proinflammatory cytokines were not able to upregulate HO-1. Heme oxygenase-1 protects the cells against NO by feedback inhibition of NO production and by decreasing cell damage.

Suppression of lipopolysaccharide-induced of inducible nitric oxide synthase and cyclooxygenase-2 by Sanguis Draconis, a dragon's blood resin, in RAW 264.7 cells

Sanguis Draconis (SD) is a kind of dragon's blood resin that is obtained from Daemomorops draco (Palmae). It is used in traditional medicine and has shown anti-inflammatory activity in some diseases. In this study, we examined the effects of Sanguis Dranonis ethanol extract (SDEE) on LPS-induced inflammation using RAW 264.7 cells. Our data indicated that SDEE inhibits LPS-stimulated NO, PGE2, IL-1 beta and TNF-alpha release, and iNOS and COX-2 expression. Furthermore, SDEE suppressed the LPS-induced p65 expression of NF-kappa B, which was associated with the inhibition of I kappa B-alpha degradation. We also found that the expression of HO-1 was significantly increased in RAW 264.7 cells by SDEE. These results suggest among possibilities of anti-inflammation that SDEE inhibits the production of NO and PGE2 by the down-regulation of iNOS and COX-2 gene expression via the suppression of NF-kappaB (p65) activation. SDEE can induce HO-1 over-expression in macrophage cells, which indicates that it may possess antioxidant properties. This result means that SEDD its anti-inflammatory effects in macrophages may be through a novel mechanism that involves the action of HO-1. Thus, SD could provide a potential therapeutic approach for inflammation-associated disorders.