Heme Oxygenase-1 is an Essential Cytoprotective Component in Oxidative Tissue Injury Induced by Hemorrhagic Shock

Immunocytochemical Analysis of Crocin against Oxidative Stress in Trigeminal Sensory Neurons Innervating the Cornea

Corneal diseases are a major cause of vision loss, often associated with aging, trauma and disease. Damage to corneal sensory innervation leads to discomfort and pain. Environmental stressors, such as short-wavelength light, can induce oxidative stress that alters mitochondrial function and affects cell and tissue homeostasis, including corneal innervation. Cellular antioxidant mechanisms may attenuate oxidative stress. This study investigates crocin, a derivative of saffron, as a potential antioxidant therapy. In vitro rat trigeminal sensory ganglion neurons were exposed to both sodium azide and blue light overexposure as a model of oxidative damage. Crocin was used as a neuroprotective agent. Mitochondrial and cytoskeletal markers were studied by immunofluorescence analysis to determine oxidative damage and neuroprotection. In vivo corneal innervation degeneration was evaluated in cornea whole mount preparations using Sholl analyses. Blue light exposure induces oxidative stress that affects trigeminal neuron mitochondria and alters sensory axon dynamics in vitro, and it also affects corneal sensory innervation in an in vivo model. Our results show that crocin was effective in preserving mitochondrial function and protecting corneal sensory neurons from oxidative stress. Crocin appears to be a promising candidate for the neuroprotection of corneal innervation.

Histidine-rich protein II nanoparticle delivery of heme iron load drives endothelial inflammation in cerebral malaria

Histidine-rich protein II (HRPII) is secreted by Plasmodium falciparum during the blood stage of malaria infection. High plasma levels of HRPII are associated with cerebral malaria, a severe and highly fatal complication of malaria. HRPII has been shown to induce vascular leakage, the hallmark of cerebral malaria, in blood-brain barrier (BBB) and animal models. We have discovered an important mechanism for BBB disruption that is driven by unique features of HRPII. By characterizing serum from infected patients and HRPII produced by P. falciparum parasites in culture, we found that HRPII exists in large multimeric particles of 14 polypeptides that are richly laden with up to 700 hemes per particle. Heme loading of HRPII is required for efficient binding and internalization via caveolin-mediated endocytosis in hCMEC/D3 cerebral microvascular endothelial cells. Upon acidification of endolysosomes, two-thirds of the hemes are released from acid-labile binding sites and metabolized by heme oxygenase 1, generating ferric iron and reactive oxygen species. Subsequent activation of the NLRP3 inflammasome and IL-1β secretion resulted in endothelial leakage. Inhibition of these pathways with heme sequestration, iron chelation, or anti-inflammatory drugs protected the integrity of the BBB culture model from HRPII:heme. Increased cerebral vascular permeability was seen after injection of young mice with heme-loaded HRPII (HRPII:heme) but not with heme-depleted HRPII. We propose that during severe malaria infection, HRPII:heme nanoparticles in the bloodstream deliver an overwhelming iron load to endothelial cells to cause vascular inflammation and edema. Disrupting this process is an opportunity for targeted adjunctive therapies to reduce the morbidity and mortality of cerebral malaria.

The metabolic landscape in chronic rotator cuff tear reveals tissue-region-specific signatures

BACKGROUND

Degeneration of shoulder muscle tissues often result in tearing, causing pain, disability and loss of independence. Differential muscle involvement patterns have been reported in tears of shoulder muscles, yet the molecules involved in this pathology are poorly understood. The spatial distribution of biomolecules across the affected tissue can be accurately obtained with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). The goal of this pilot study was to decipher the metabolic landscape across shoulder muscle tissues and to identify signatures of degenerated muscles in chronic conditions.

METHODS

Paired biopsies of two rotator cuff muscles, torn infraspinatus and intact teres minor, together with an intact shoulder muscle, the deltoid, were collected during an open tendon transfer surgery. Five patients, average age 65.2 ± 3.8 years, were selected for spatial metabolic profiling using high-spatial resolution (MALDI-TOF) and high-mass resolution (MALDI-FTICR) MSI in negative or positive ion mode. Metabolic signatures were identified using data-driven analysis. Verifications of spatial localization for selected metabolic signatures were carried out using antibody immunohistology.

RESULTS

Data-driven analysis revealed major metabolic differences between intact and degenerated regions across all muscles. The area of degenerated regions, encompassed of fat, inflammation and fibrosis, significantly increased in both rotator cuff muscles, teres minor (27.9%) and infraspinatus (22.8%), compared with the deltoid (8.7%). The intact regions were characterized by 49 features, among which lipids were recognized. Several of the identified lipids were specifically enriched in certain myofiber types. Degenerated regions were specifically marked by the presence of 37 features. Heme was the most abundant metabolite in degenerated regions, whereas Heme oxygenase-1 (HO-1), which catabolizes heme, was found in intact regions. Higher HO-1 levels correlated with lower heme accumulation.

CONCLUSIONS

Degenerated regions are distinguished from intact regions by their metabolome profile. A muscle-specific metabolome profile was not identified. The area of tissue degeneration significantly differs between the three examined muscles. Higher HO-1 levels in intact regions concurred with lower heme levels in degenerated regions. Moreover, HO-1 levels discriminated between dysfunctional and functional rotator cuff muscles. Additionally, the enrichment of specific lipids in certain myofiber types suggests that lipid metabolism differs between myofiber types. The signature metabolites can open options to develop personalized treatments for chronic shoulder muscles degeneration.

Effects of Sodium Thiosulfate During Resuscitation From Trauma-and-Hemorrhage in Cystathionine Gamma Lyase (CSE) Knockout Mice

BACKGROUND

Sodium thiosulfate (Na2S2O3) is a clinically established drug with antioxidant and sulphide-releasing properties. Na2S2O3 mediated neuro- and cardioprotective effects in ischemia/reperfusion models and anti-inflammatory effects in LPS-induced acute lung injury. Moreover, Na2S2O3 improved lung function during resuscitation from hemorrhagic shock in swine with pre-existing atherosclerosis, characterized by decreased expression of cystathionine γ-lyase (CSE), a major source of hydrogen sulfide (H2S) synthesis in the vasculature. Based on these findings, we investigated the effects of Na2S2O3 administration during resuscitation from trauma-and-hemorrhage in mice under conditions of whole body CSE deficit.

METHODS

After blast wave-induced blunt chest trauma and surgical instrumentation, CSE knockout (CSE-/-) mice underwent 1 h of hemorrhagic shock (MAP 35 ± 5 mm Hg). At the beginning of resuscitation comprising retransfusion, norepinephrine support and lung-protective mechanical ventilation, animals received either i.v. Na2S2O3 (0.45 mg g-1, n = 12) or vehicle (saline, n = 13). Hemodynamics, acid-base status, metabolism using stable isotopes, and visceral organ function were assessed. Blood and organs were collected for analysis of cytokines, mitochondrial respiratory capacity, and immunoblotting.

RESULTS

Na2S2O3 treatment improved arterial paO2 (P = 0.03) coinciding with higher lung tissue glucocorticoid receptor expression. Norepinephrine requirements were lower in the Na2S2O3 group (P < 0.05), which was associated with lower endogenous glucose production and higher urine output. Na2S2O3 significantly increased renal tissue IκBα and heme oxygenase-1 expression, whereas it lowered kidney IL-6 and MCP-1 levels.

CONCLUSION

Na2S2O3 exerted beneficial effects during resuscitation of murine trauma-and-hemorrhage in CSE-/- mice, confirming and extending the previously described organ-protective and anti-inflammatory properties of Na2S2O3. The findings make Na2S2O3 a potentially promising therapeutic option in the context of impaired CSE activity and/or reduced endogenous H2S availability.

Mangiferin mitigates di-(2-ethylhexyl) phthalate-induced testicular injury in rats by modulating oxidative stress-mediated signals, inflammatory cascades, apoptotic pathways, and steroidogenesis

Di-(2-ethylhexyl) phthalate (DEHP) is an endocrine disruptor that causes reproductive defects in male animal models. This study was conducted to explore the plausible modulatory effects of mangiferin (MF) against DEHP-induced testicular injury in rats. Thirty-two adult male albino rats were allocated into four groups. Two groups were given DEHP (2 g/kg/day, p.o) for 14 days. One of these groups was treated with MF (20 mg/kg/day, i.p) for 7 days before and 14 days after DEHP administration. A vehicle-treated control was included, and another group of rats was given MF only. Results revealed that MF treatment suppressed oxidative testicular injury by amplifying the mRNA expression of nuclear factor-erythroid 2 related factor-2 (Nrf2) and increasing hemoxygenase-1 (HO-1), glutathione, and total antioxidant capacity (TAC) levels. This treatment also enhanced superoxide dismutase activity, but it decreased malondialdehyde and nitric oxide levels. MF had an anti-inflammatory characteristic, as demonstrated by the downregulation of the mRNA of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The content of tumor necrosis factor-alpha also decreased. MF modulated the apoptotic pathway by suppressing the mRNA of cytochrome c (Cyt c), Fas ligand content, Bax IHC expression, caspase-3 activity and cleaved caspase-3 IHC expression. It also upregulated the expression levels of heat-shock protein 70 (HSP70) and B-cell lymphoma 2. Moreover, MF upregulated the mRNA expression levels of HSP70 and c-kit and enriched the content of steroidogenic acute regulatory (StAR) protein, which were reflected in serum testosterone levels. This result indicated that MF played crucial roles in steroidogenesis and spermatogenesis. Besides, the activities of testicular marker enzymes, namely, acid and alkaline phosphatases, and lactate dehydrogenase, significantly increased. Histopathological observations provided evidence supporting the biochemical and molecular measurements. In conclusion, MF provided protective mechanisms against the DEHP-mediated deterioration of testicular functions partially through its antioxidant, anti-inflammatory, and anti-apoptotic properties. It also involved the restoration of steroidogenesis and spermatogenesis through the modulation of Nrf2/HO-1, NF-κB/Cyt c/HSP70, and c-Kit signaling cascades.

Gaseous Mediators as a Key Molecular Targets for the Development of Gastrointestinal-Safe Anti-Inflammatory Pharmacology

Non-steroidal anti-inflammatory drugs (NSAIDs) represent one of the most widely used classes of drugs and play a pivotal role in the therapy of numerous inflammatory diseases. However, the adverse effects of these drugs, especially when applied chronically, frequently affect gastrointestinal (GI) tract, resulting in ulceration and bleeding, which constitutes a significant limitation in clinical practice. On the other hand, it has been recently discovered that gaseous mediators nitric oxide (NO), hydrogen sulfide (H₂S) and carbon monoxide (CO) contribute to many physiological processes in the GI tract, including the maintenance of GI mucosal barrier integrity. Therefore, based on the possible therapeutic properties of NO, H₂S and CO, a novel NSAIDs with ability to release one or more of those gaseous messengers have been synthesized. Until now, both preclinical and clinical studies have shown promising effects with respect to the anti-inflammatory potency as well as GI-safety of these novel NSAIDs. This review provides an overview of the gaseous mediators-based NSAIDs along with their mechanisms of action, with special emphasis on possible implications for GI mucosal defense mechanisms.

Lutein Exerts Antioxidant and Anti-Inflammatory Effects and Influences Iron Utilization of BV-2 Microglia

Lutein is a tetraterpene carotenoid, which has been reported as an important antioxidant and it is widely used as a supplement. Oxidative stress participates in many human diseases, including different types of neurodegenerative disorders. Microglia, the primary immune effector cells in the central nervous system, are implicated in these disorders by producing harmful substances such as reactive oxygen species (ROS). The protective mechanisms which scavenge ROS include enzymes and antioxidant substances. The protective effects of different carotenoids against oxidative stress have been described previously. Our study focuses on the effects of lutein on antioxidant enzymes, cytokines and iron metabolism under stress conditions in BV-2 microglia. We performed cell culture experiments: BV-2 cells were treated with lutein and/or with H₂O₂; the latter was used for inducing oxidative stress in microglial cells. Real-time PCR was performed for gene expression analyses of antioxidant enzymes, and ELISA was used for the detection of pro- and anti-inflammatory cytokines. Our results show that the application of lutein suppressed the H₂O₂-induced ROS (10′: 7.5 ng + 10 µM H₂O₂, p = 0.0002; 10 ng/µL + 10 µM H₂O₂, p = 0.0007), influenced iron utilization and changed the anti-inflammatory and pro-inflammatory cytokine secretions in BV-2 cells. Lutein increased the IL-10 secretions compared to control (24 h: 7.5 ng/µL p = 0.0274; 10 ng/µL p = 0.0008) and to 10 µM H₂O₂-treated cells (24 h: 7.5 ng/µL + H₂O₂, p = 0.0003; 10 ng/µL + H₂O₂, p = 0.0003), while it decreased the TNFα secretions compared to H₂O₂ treated cells (24 h: 7.5 ng/µL + H₂O₂, p < 0.0001; 10 ng/µL + H₂O₂, p < 0.0001). These results contribute to understanding the effects of lutein, which may help in preventing or suppressing ROS-mediated microglia activation, which is related to neuronal degeneration in oxidative stress scenario.

A Novel Antioxidant Protects Against Contrast Medium-Induced Acute Kidney Injury in Rats

Many studies proposed that oxidative stress and apoptosis are key mechanisms in the pathogenesis of contrast-induced acute kidney injury (CI-AKI). Xylose-pyrogallol conjugate (XP) is an original effective antioxidant that showed decent antioxidant and anti-apoptosis effect before. Thus the therapeutic effect and mechanism of XP in preventing CI-AKI in the short and long term were investigated in this research. Renal function and histological grade were evaluated to determine the severity of renal injury. Kidney samples were then collected for the measurement of oxidative stress markers and the detection of apoptosis. Transmission electron microscopy (TEM) and western blot of mitochondrial protein were utilized for the analysis of the mitochondrial conditions. The results demonstrated that the CI-AKI rats caused a significant decrease in renal function accompanied by a remarkable increase in Malondialdehyde (MDA), bax, caspase-3, cytochrome c (Cyt C) level, TdT-mediated dUTP nick end labeling (TUNEL) positive apoptotic cells, and damaged mitochondria, while a decline in antioxidase activities and mitochondrial superoxide dismutase 2 (SOD2) expression compared with the control rats. However, when XP (50 or 100 or 200 mg/kg/day) was given orally for consecutive 7 days before CI-AKI modeling, XP (200 mg/kg) showed a better capability to restore renal dysfunction, histopathological appearance, the level of apoptosis, mitochondrial damage, oxidative stress, and fibrosis generation without interference in computed tomographic imaging. Our study indicated that antioxidant XP played a nephroprotective role probably via antiapoptotic and antioxidant mechanisms. Besides, XP may regulate the mitochondria pathway via decreasing the ratio of bax/bcl-2, inhibiting caspase-3 expression, cytochrome c release, and superoxide dismutase 2 activity. Overall, XP as a high-efficient antioxidant may have the potentials to prevent CI-AKI.

Anti-apoptosis effect of heme oxygenase-1 on lung injury after cardiopulmonary bypass

Background

This study aimed to investigate the anti-apoptosis effects of heme oxygenase-1 (HO-1) on lung injury (LI) after cardiopulmonary bypass (CPB) and its probable mechanisms.

Methods

One hundred and forty-four male Wistar rats were divided into 3 groups randomly: group A (control group), group B (cobalt protoporphyrin, CoPP), and group C [CoPP plus zinc protoporphyrin (ZnPP)]. Lung tissues were harvested at different time: before CPB (T0), 0 min after CPB (T1), 2 h after CPB (T2), 6 h (T3), 12 h (T4), and 24 h (T5).

Results

The HO-1 protein expressions in lung tissue in group B were higher than those in group A and group C in any given time, and the same as HO-1 activity (P<0.05). The expressions of Bcl-2 protein in group B at all time point after bypass were higher than those in group A and group C, and the difference was statistically significant (P<0.05). Apoptosis index (AI) in group B at any time point after bypass were lower than those in group A and group C (P<0.05).

Conclusions

CoPP can significantly increase the expression of HO-1 protein in lung tissue. HO-1 is still highly expressed after CPB, so as to play an important part in anti-apoptosis, and reduce LI.

Effect of Polyethylene-glycolated Carboxyhemoglobin on Renal Microcirculation in a Rat Model of Hemorrhagic Shock

BACKGROUND

Primary resuscitation fluid to treat hemorrhagic shock remains controversial. Use of hydroxyethyl starches raised concerns of acute kidney injury. Polyethylene-glycolated carboxyhemoglobin, which has carbon monoxide-releasing molecules and oxygen-carrying properties, was hypothesized to sustain cortical renal microcirculatory PO2 after hemorrhagic shock and reduce kidney injury.

METHODS

Anesthetized and ventilated rats (n = 42) were subjected to pressure-controlled hemorrhagic shock for 1 h. Renal cortical PO2 was measured in exposed kidneys using a phosphorescence quenching method. Rats were randomly assigned to six groups: polyethylene-glycolated carboxyhemoglobin 320 mg · kg, 6% hydroxyethyl starch (130/0.4) in Ringer's acetate, blood retransfusion, diluted blood retransfusion (~4 g · dl), nonresuscitated animals, and time control. Nitric oxide and heme oxygenase 1 levels were determined in plasma. Kidney immunohistochemistry (histologic scores of neutrophil gelatinase-associated lipocalin and tumor necrosis factor-α) and tubular histologic damages analyses were performed.

RESULTS

Blood and diluted blood restored renal PO2 to 51 ± 5 mmHg (mean difference, -18; 95% CI, -26 to -11; P < 0.0001) and 47 ± 5 mmHg (mean difference, -23; 95% CI, -31 to -15; P < 0.0001), respectively, compared with 29 ± 8 mmHg for hydroxyethyl starch. No differences between polyethylene-glycolated carboxyhemoglobin and hydroxyethyl starch were observed (33 ± 7 mmHg vs. 29 ± 8 mmHg; mean difference, -5; 95% CI, -12 to 3; P = 0.387), but significantly less volume was administered (4.5 [3.3-6.2] vs. 8.5[7.7-11.4] ml; mean rank difference, 11.98; P = 0.387). Blood and diluted blood increased the plasma bioavailability of nitric oxide compared with hydroxyethyl starch (mean rank difference, -20.97; P = 0.004; and -17.13; P = 0.029, respectively). No changes in heme oxygenase 1 levels were observed. Polyethylene-glycolated carboxyhemoglobin limited tubular histologic damages compared with hydroxyethyl starch (mean rank difference, 60.12; P = 0.0012) with reduced neutrophil gelatinase-associated lipocalin (mean rank difference, 84.43; P < 0.0001) and tumor necrosis factor-α (mean rank difference, 49.67; P = 0.026) histologic scores.

CONCLUSIONS

Polyethylene-glycolated carboxyhemoglobin resuscitation did not improve renal PO2 but limited tubular histologic damages and neutrophil gelatinase-associated lipocalin upregulation after hemorrhage compared with hydroxyethyl starch, whereas a lower volume was required to sustain macrocirculation.

Microcellular Environmental Regulation of Silver Nanoparticles in Cancer Therapy: A Critical Review

Silver nanoparticles (AgNPs) play significant roles in various cancer cells such as functional heterogeneity, microenvironmental differences, and reversible changes in cell properties (e.g., chemotherapy). There is a lack of targets for processes involved in tumor cellular heterogeneity, such as metabolic clampdown, cytotoxicity, and genotoxicity, which hinders microenvironmental biology. Proteogenomics and chemical metabolomics are important tools that can be used to study proteins/genes and metabolites in cells, respectively. Chemical metabolomics have many advantages over genomics, transcriptomics, and proteomics in anticancer therapy. However, recent studies with AgNPs have revealed considerable genomic and proteomic changes, particularly in genes involved in tumor suppression, apoptosis, and oxidative stress. Metabolites interact biochemically with energy storage, neurotransmitters, and antioxidant defense systems. Mechanobiological studies of AgNPs in cancer metabolomics suggest that AgNPs may be promising tools that can be exploited to develop more robust and effective adaptive anticancer therapies. Herein, we present a proof-of-concept review for AgNPs-based proteogenomics and chemical metabolomics from various tumor cells with the help of several technologies, suggesting their promising use as drug carriers for cancer therapy.

HO-1 and CD39: It Takes Two to Protect the Realm

Cellular protective mechanisms exist to ensure survival of the cells and are a fundamental feature of all cells that is necessary for adapting to changes in the environment. Indeed, evolution has ensured that each cell is equipped with multiple overlapping families of genes that safeguard against pathogens, injury, stress, and dysfunctional metabolic processes. Two of the better-known enzymatic systems, conserved through all species, include the heme oxygenases (HO-1/HO-2), and the ectonucleotidases (CD39/73). Each of these systems generates critical bioactive products that regulate the cellular response to a stressor. Absence of these molecules results in the cell being extremely predisposed to collapse and, in most cases, results in the death of the cell. Recent reports have begun to link these two metabolic pathways, and what were once exclusively stand-alone are now being found to be intimately interrelated and do so through their innate ability to generate bioactive products including adenosine, carbon monoxide, and bilirubin. These simple small molecules elicit profound cellular physiologic responses that impact a number of innate immune responses, and participate in the regulation of inflammation and tissue repair. Collectively these enzymes are linked not only because of the mitochondria being the source of their substrates, but perhaps more importantly, because of the impact of their products on specific cellular responses. This review will provide a synopsis of the current state of the field regarding how these systems are linked and how they are now being leveraged as therapeutic modalities in the clinic.

Therapeutic effect of carbon monoxide-releasing molecule-3 on acute lung injury after hemorrhagic shock and resuscitation

Hemorrhagic shock and resuscitation (HSR) induces a pulmonary inflammatory response and frequently causes acute lung injury. Carbon monoxide-releasing molecule-3 (CORM-3) has been reported to liberate and deliver CO under physiological conditions, which exerts organ-protective effects during systemic insults. The present study aimed to determine whether the administration of CORM-3 following HSR exerts a therapeutic effect against HSR-induced lung injury without any detrimental effects on oxygenation and hemodynamics. To induce hemorrhagic shock, rats were bled to a mean arterial blood pressure of 30 mmHg for 45 min and then resuscitated with the shed blood. CORM-3 or a vehicle was intravenously administered immediately following the completion of resuscitation. The rats were divided into four groups, including sham, HSR, HSR/CORM-3 and HSR/inactive CORM-3 groups. Arterial blood gas parameters and vital signs were recorded during HSR. The histopathological changes to the lungs were evaluated using a lung injury score, while pulmonary edema was evaluated on the basis of the protein concentration in bronchoalveolar lavage fluid and the lung wet/dry ratio. We also investigated the pulmonary expression levels of inflammatory mediators and apoptotic markers such as cleaved caspase-3 and transferase-mediated dUTP-fluorescein isothiocyanate nick-end labeling (TUNEL) staining. Although HSR caused significant lung histopathological damage and pulmonary edema, CORM-3 significantly ameliorated this damage. CORM-3 also attenuated the HSR-induced upregulation of tumor necrosis factor-α, inducible nitric oxide synthase and interleukin-1β genes, and the expression of interleukin-1β and macrophage inflammatory protein-2. In addition, the expression of interleukin-10, an anti-inflammatory cytokine, was inversely enhanced by CORM-3, which also reduced the number of TUNEL-positive cells and the expression of cleaved caspase-3 following HSR. Although CORM-3 was administered during the acute phase of HSR, it did not exert any influence on arterial blood gas analysis data and vital signs during HSR. Therefore, treatment with CORM-3 ameliorated HSR-induced lung injury, at least partially, through anti-inflammatory and anti-apoptotic effects, without any detrimental effects on oxygenation and hemodynamics.

The protective effect of epigallocatechin 3-gallate on mouse pancreatic islets via the Nrf2 pathway

PURPOSE

Epigallocatechin 3-gallate (EGCG), a green tea polyphenol, has been shown to have anti-oxidant and anti-inflammatory effects in vitro and in vivo. The aim of this study was to investigate the effects and mechanism of EGCG on isolated pancreatic islets as pre-conditioning for pancreatic islet transplantation.

METHODS

The pancreatic islets were divided into two groups: an islet culture medium group (control) and an islet culture medium with EGCG (100 µM) group. We investigated the islet viability, Nrf2 expression, reactive oxygen species (ROS) production, and heme oxygenase-1 (HO-1) mRNA. Five hundred islet equivalents after 12 h of culture for the EGCG 100 µM and control group were transplanted under the kidney capsule of streptozotocin-induced diabetic ICR mice.

RESULTS

The cell viability and insulin secretion ability in the EGCG group were preserved, and the nuclear translocation of Nrf2 was increased in the EGCG group (p < 0.01). While the HO-1 mRNA levels were also higher in the EGCG group than in the control group (p < 0.05), the ROS production was lower (p < 0.01). An in vivo functional assessment showed that the blood glucose level had decreased in the EGCG group after transplantation (p < 0.01).

CONCLUSION

EGCG protects the viability and function of islets by suppressing ROS production via the Nrf2 pathway.

Telluric Acid Ameliorates Endotoxemic Kidney Injury in Mice: Involvement of TLR4, Nrf2, and PI3K/Akt Signaling Pathways

Being one of the most abundant trace elements in the human body, the therapeutic potential of tellurium-based compounds has been a target of interest. Recent reports denoted their redox-modulating and anti-inflammatory activities in experimental endotoxemia. However, their potential nephroprotective effect against endotoxemic kidney injury is yet to be elucidated. This study investigated the possible renoprotective effect of telluric acid (TEL) against lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in mice, targeting toll-like receptor 4 (TLR4), phosphoinositide 3-kinase (PI3K)/Akt, and nuclear factor-erythroid 2-related factor-2 (Nrf2) pathways as possible mechanistic contributors to TEL's effect. AKI was induced by LPS (2 mg/kg). TEL (60 μg/kg; i.p.) was administered once daily for seven consecutive days before LPS injection. Pretreatment with TEL alleviated LPS-induced AKI as evidenced by the hampered serum levels of creatinine and cystatin C. TEL also opposed LPS-induced elevation in renal kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, nuclear factor-kappa B p65, interleukin-1β, and thiobarbituric acid-reactive substance contents. This was accompanied by a replenishment of renal glutathione, transcriptional upregulation of Nrf2, enhancement of heme oxygenase-1 activity, and a marked upregulation of phospho-PI3K and phospho-Akt protein expressions. Histopathological findings corroborated with the amendment of biochemical parameters. In view of these findings, we may conclude that TEL pretreatment purveyed novel nephroprotective effects against endotoxemic kidney injury, which might be partly attributed to the modulation of TLR4, PI3K/Akt, and Nrf2 signaling pathways and may hence provide a valuable asset for the management of endotoxemic renal complications.

A systematic review on silver nanoparticles-induced cytotoxicity: Physicochemical properties and perspectives

With the development of nanotechnology, silver nanoparticles (Ag-NPs) have become one of the most in-demand nanoparticles owing to their exponential number of uses in various sectors. The increased use of Ag-NPs-enhanced products may result in an increased level of toxicity affecting both the environment and living organisms. Several studies have used different model cell lines to exhibit the cytotoxicity of Ag-NPs, and their underlying molecular mechanisms. This review aimed to elucidate different properties of Ag-NPs that are responsible for the induction of cellular toxicity along with the critical mechanism of action and subsequent defense mechanisms observed in vitro. Our results show that the properties of Ag-NPs largely vary based on the diversified synthesis processes. The physiochemical properties of Ag-NPs (e.g., size, shape, concentration, agglomeration, or aggregation interaction with a biological system) can cause impairment of mitochondrial function prior to their penetration and accumulation in the mitochondrial membrane. Thus, Ag-NPs exhibit properties that play a central role in their use as biocides along with their applicability in environmental cleaning. We herein report a current review of the synthesis, applicability, and toxicity of Ag-NPs in relation to their detailed characteristics.

Elaidic acid induces cell apoptosis through induction of ROS accumulation and endoplasmic reticulum stress in SH‑SY5Y cells

Elaidic acid, which is a major trans fatty acid, has been reported to be involved in neurotoxicity; however, the underlying molecular mechanisms underlying its neurotoxic effects remain largely unknown. Therefore, the present study aimed to investigate the potential mechanisms underlying elaidic acid‑induced neuronal damage in vitro. The SH‑SY5Y neuroblastoma cell line was used as a model in the present study. Following treatment of cells with various concentrations of elaidic acid or with vehicle for 24 h, cell viability was measured using the MTT assay. Mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) release were measured using flow cytometry. Cell apoptosis was measured by Annexin V‑fluorescein isothiocyanate/propidium iodide double staining, and cellular redox status was determined using ELISA analysis. Furthermore, western blotting was used to detect the protein expression levels of factors associated with oxidative damage and components of the endoplasmic reticulum (ER) stress/unfolded protein response (UPR) signaling pathways. The results demonstrated that elaidic acid treatment inhibited cell viability, elevated cell apoptosis and resulted in a loss of MMP. In addition, elaidic acid induced marked alterations in cellular redox status. Treatment with high doses of elaidic acid treatment also enhanced the release of ROS, and upregulated lipid peroxide and malondialdehyde levels; however, it reduced superoxide dismutase and glutathione peroxidase activities. Furthermore, elaidic acid resulted in upregulation of nuclear factor erythroid 2‑related factor 2 and downregulation of heme oxygenase 1, which are two key antioxidative factors. Elaidic acid treatment also induced or inhibited the expression of numerous ER stress/UPR‑associated molecules. It induced glucose‑regulated protein 78 (GRP78) expression, whereas the expression levels of activating transcription factor 4 (ATF4) and CCAAT/enhancer‑binding protein homologous protein (CHOP) were upregulated and then downregulated following treatment with various doses of elaidic acid. These results indicated that elaidic acid inhibited SH‑SY5Y cell growth and induced apoptosis by enhancing oxidative stress and activating the ER stress/UPR signaling pathway and the GRP78/ATF4/CHOP pathway.

Biliverdin Protects the Isolated Rat Lungs from Ischemia-reperfusion Injury via Antioxidative, Anti-inflammatory and Anti-apoptotic Effects

Background:

Biliverdin (BV) has a protective role against ischemia-reperfusion injury (IRI). However, the protective role and potential mechanisms of BV on lung IRI (LIRI) remain to be elucidated. Thus, we aimed to investigate the protective role and potential mechanisms of BV on LIRI.

Methods:

Lungs were isolated from Sprague-Dawley rats to establish an ex vivo LIRI model. After an initial 15 min stabilization period, the isolated lungs were subjected to ischemia for 60 min, followed by 90 min of reperfusion with or without BV treatment.

Results:

Lungs in the I/R group exhibited significant decrease in tidal volume (1.44 ± 0.23 ml/min in I/R group vs. 2.41 ± 0.31 ml/min in sham group; P < 0.001), lung compliance (0.27 ± 0.06 ml/cmH₂O in I/R group vs. 0.44 ± 0.09 ml/cmH₂O in sham group; P < 0.001; 1 cmH₂O=0.098 kPa), and oxygen partial pressure (PaO₂) levels (64.12 ± 12 mmHg in I/R group vs. 114 ± 8.0 mmHg in sham group; P < 0.001; 1 mmHg = 0.133 kPa). In contrast, these parameters in the BV group (2.27 ± 0.37 ml/min of tidal volume, 0.41 ± 0.10 ml/cmH₂O of compliance, and 98.7 ± 9.7 mmHg of PaO₂) were significantly higher compared with the I/R group (P = 0.004, P < 0.001, and P < 0.001, respectively). Compared to the I/R group, the contents of superoxide dismutase were significantly higher (47.07 ± 7.91 U/mg protein vs. 33.84 ± 10.15 U/mg protein; P = 0.005) while the wet/dry weight ratio (P < 0.01), methane dicarboxylic aldehyde (1.92 ± 0.25 nmol/mg protein vs. 2.67 ± 0.46 nmol/mg protein; P < 0.001), and adenosine triphosphate contents (297.05 ± 47.45 nmol/mg protein vs. 208.09 ± 29.11 nmol/mg protein; P = 0.005) were markedly lower in BV-treated lungs. Histological analysis revealed that BV alleviated LIRI. Furthermore, the expression of inflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor-β) was downregulated and the expression of cyclooxygenase-2, inducible nitric oxide synthase, and Jun N-terminal kinase was significantly reduced in BV group (all P < 0.01 compared to I/R group). Finally, the apoptosis index in the BV group was significantly decreased (P < 0.01 compared to I/R group).

Conclusion:

BV protects lung IRI through its antioxidative, anti-inflammatory, and anti-apoptotic effects.

Biliary tract external drainage protects against multiple organs injuries of severe acute pancreatitis rats via heme oxygenase-1 upregulation

OBJECTIVE

To investigate the effect of biliary tract external drainage (BTED) on severe acute pancreatitis (SAP) in rats and the relationship with heme oxygenase-1 (HO-1) pathway.

METHODS

Thirty SD rats weighing 250-300 g were randomly assigned into five groups (n = 6): sham surgery (SS) group, SAP group, SAP + BTED group, SAP + zinc protoporphyrin IX (ZnPP) group, SAP + BTED + ZnPP group. The SAP model was induced via retrograde injection of 4% sodium taurocholate (1 mL/kg) into biliopancreatic duct through duodenal wall. BTED was performed by inserting a cannula into the bile duct of SAP rats. Tissue and blood samples were collected 24 h after surgery. Pathological changes in organs were scored. The level of amylase, alanine transaminase (ALT), aspartate aminotransferase (AST), diamine oxidase (DAO), lipopolysaccharide (LPS), myeloperoxidase (MPO) and ability to inhibit hydroxyl radical(·OH) in serum were measured. The expression of hemeoxygenase-1 (HO-1), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in tissues were analyzed by RT- PCR and western-blot.

RESULTS

Organs damage in SAP rats was significantly alleviated by BTED (p < 0.05). Compared to the SAP group, the serum level of amylase, ALT, AST, DAO, MPO, and LPS were significantly lower in the SAP + BTED group, and the ability to inhibit ·OH was significantly higher (p < 0.05). The BETD treatment led to a significant reduction of TNF-α, IL-6 level and a significant increase of HO-1 level in tissues than in SAP rats (p < 0.05). ZnPP significantly inhibited all above mentioned changes.

CONCLUSIONS

BTED protected multiple organs against SAP related injuries via HO-1 upregulation.

BJ-1103, 6-aminopyridin-3-ol skeletal compound, modulates neuroprotective and anti-neuroinflammatory effects in murine hippocampal and microglial cells via Nrf2-mediated heme oxygenase-1 expression

BJ-1103, as a 6-aminopyridin-3-ol skeletal compound, was originally developed as an antioxidant against free radicals and oxidative stress was prepared from pyridoxine·HCl by the reported procedure. In the present study, we examined the effect of BJ-1103 on neuroprotection and neuroinflammation. Our data showed that BJ-1103 can protect HT22 cells against glutamate-induced cell cytotoxicity. And, BJ-1103 also inhibited LPS-induced inflammatory action. In addition, BJ-1103-induced heme oxygenase-1 (HO-1) expression and elevated HO-1 activities in the two cell lines studied. Additionally, BJ-1103 treatment induced nuclear transcription factor erythroid-2 related factor 2 (Nrf2) and increased the promoter activity of antioxidant response elements (AREs). We have demonstrated using the Nrf2 siRNA, HO inhibitor or HO-1 siRNA that BJ-1103 suppressed neurotoxicity and neuroinflammation through the Nrf2-mediated HO-1 expression. These results demonstrated that BJ-1103 may have good therapeutic agent against neurodegenerative diseases that are induced by oxidative stress and neuroinflammation.

Targeting HO-1 by Epigallocatechin-3-Gallate Reduces Contrast-Induced Renal Injury via Anti-Oxidative Stress and Anti-Inflammation Pathways

Both oxidative stress and inflammation are involved in the pathogenesis of contrast-induced nephropathy (CIN). Epigallocatechin-3-gallate (EGCG), a purified catechin from green tea, has antioxidant and anti-inflammatory effects. However, it is unknown whether or not EGCG is effective in treating CIN. Our present study found that intravenous administration of EGCG, either before or just after the establishment of CIN, had a protective effect, determined by normalization of serum creatinine and blood urea nitrogen levels, improvement in renal histopathological scoring and alleviation of apoptosis, accompanied by decreased oxidative stress and inflammation. Because EGCG is a potent inducer of the antioxidant heme oxygenase-1 (HO-1), we studied HO-1 signaling in CIN. HO-1 levels were increased in CIN; treatment with EGCG further increased HO-1 levels, accompanied by an increase in Nrf2, a regulator of antioxidant proteins. Interestingly, blockade of HO-1 with protoporphyrin IX zinc(II) (ZnPP) prevented the protective effect of EGCG on CIN. ZnPP also blocked the ability of EGCG to increase the activity of an antioxidant (superoxide dismutase), and decrease markers of oxidative stress (myeloperoxidase and malondialdehyde) and inflammation (myeloperoxidase and IL-1β), indicating that HO-1 is the upstream molecule that regulates the EGCG-mediated protection. To determine further the role of HO-1 on the EGCG-mediated inhibition of inflammation, we studied the effect of EGCG on the NLRP3 inflammasome, an upstream signaling of IL-1β. EGCG down-regulated NLRP3 expression, which was blocked by ZnPP, indicating that HO-1 links EGCG with NLRP3. Therefore, EGCG, via up-regulation of HO-1, protects against CIN by amelioration of oxidative stress and inflammation.

Resveratrol and curcumin ameliorate di-(2-ethylhexyl) phthalate induced testicular injury in rats

The present study aimed to evaluate the protective role of resveratrol and curcumin on oxidative testicular damage induced by di-(2-ethylhexyl) phthalate (DEHP). Male Wistar rats were divided into six groups; three groups received oral daily doses of DEHP (2g/kgBW) for 45days to induce testicular injury. Two of these groups received either resveratrol (80mg/kgBW) or curcumin (200mg/kgBW) orally for 30days before and 45days after DEHP administration. A vehicle-treated control group was also included. Another two groups of rats received either resveratrol or curcumin alone. Oxidative damage was observed by decreased levels of total antioxidant capacity (TAC) and glutathione (GSH) and increased malondialdehyde (MDA) level in the testes of DEHP-administered rats. Serum testosterone level as well as testicular marker enzymes activities; acid and alkaline phosphatases (ACP and ALP) and lactate dehydrogenase (LDH) showed severe declines. DEHP administration caused significant increases in the testicular gene expression levels of Nrf2, HO-1, HSP60, HSP70 and HSP90 as well as a significant decrease in c-Kit protein when compared with the control group. Histopathological observations provided evidence for the biochemical and molecular analysis. These DEHP-induced pathological alterations were attenuated by pretreatment with resveratrol and curcumin. We conclude that DEHP-induced injuries in biochemical, molecular and histological structure of testis were recovered by pretreatment with resveratrol and curcumin. The chemoprotective effects of these compounds may be due to their intrinsic antioxidant properties along with boosting Nrf2, HSP 60, HSP 70 and HSP 90 gene expression levels and as such may be useful potential tools in combating DEHP-induced testicular dysfunction.

Hericium erinaceus Inhibits TNF-α-Induced Angiogenesis and ROS Generation through Suppression of MMP-9/NF-κB Signaling and Activation of Nrf2-Mediated Antioxidant Genes in Human EA.hy926 Endothelial Cells

Hericium erinaceus (HE) is an edible mushroom that has been shown to exhibit anticancer and anti-inflammatory activities. We investigated the antiangiogenic and antioxidant potentials of ethanol extracts of HE in human endothelial (EA.hy926) cells upon tumor necrosis factor-α- (TNF-α-) stimulation (10 ng/mL). The underlying molecular mechanisms behind the pharmacological efficacies were elucidated. We found that noncytotoxic concentrations of HE (50-200 μg/mL) significantly inhibited TNF-α-induced migration/invasion and capillary-like tube formation of endothelial cells. HE treatment suppressed TNF-α-induced activity and/or overexpression of matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1). Furthermore, HE downregulated TNF-α-induced nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) followed by suppression of I-κB (inhibitor-κB) degradation. Data from fluorescence microscopy illustrated that increased intracellular ROS production upon TNF-α-stimulation was remarkably inhibited by HE pretreatment in a dose-dependent manner. Notably, HE triggered antioxidant gene expressions of heme oxygenase-1 (HO-1), γ-glutamylcysteine synthetase (γ-GCLC), and glutathione levels, which may contribute to inhibition of ROS. Increased antioxidant status was associated with upregulated nuclear translocation and transcriptional activation of NF-E2 related factor-2 (Nrf2) in HE treated cells. Our findings conclude that antiangiogenic and anti-inflammatory activities of H. erinaceus may contribute to its anticancer property through modulation of MMP-9/NF-κB and Nrf2-antioxidant signaling pathways.

Cytoprotective role of heme oxygenase-1 in liver ischemia reperfusion injury

Ischemia/reperfusion (I/R) injury is the main cause of graft dysfunction and failure in vascular occlusion both during liver surgery and during liver transplantation. The pathophysiology of hepatic ischemia-reperfusion includes a number of mechanisms including oxidant stress that contribute to various degrees to the overall organ damage. Heme oxygenases (HO) are essential enzymes which degrade heme into biliverdin-IXalpha, free divalent iron, and carbon monoxide (CO). Due to its anti-inflammatory, anti-apoptotic and, as recently described, anti-viral properties. The inducible HO isoform HO-1 is an important molecule which could find its way into therapy of acute and chronic liver injuries including acute liver failure, alcoholic or viral hepatitis, chronic inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma are life threatening diseases and as a consequence might result in the necessity of liver transplantation. Liver transplantation is limited by ischemia/reperfusion (I/R) injury, which is characterized by hypoxia and nutrient deficiency resulting in oxidative stress, apoptosis and immune activation. Induction of HO-1 and application predominantly of CO have been shown to interfere with liver I/R injury and to improve recipient and graft survival. HO-1 and its reaction products of heme degradation has been linked to cytoprotection, and as an inducible form of HO, serves a vital metabolic function as the rate-limiting step in the heme degradation pathway, and affords protection in models of liver I/R injury. HO-1 system is an important player in liver I/R injury condition, and may offer new targets for the management of this condition. This review aims to summarize cytoprotective role of heme oxygenase-1 (HO-1) and its products within the liver.

Cepharanthine mitigates pro-inflammatory cytokine response in lung injury induced by hemorrhagic shock/resuscitation in rats

BACKGROUND

Cepharanthine possesses strong anti-inflammation capacity. We sought to clarify whether cepharanthine could mitigate pro-inflammatory cytokine production in acute lung injury induced by hemorrhagic shock/resuscitation (HS/RES). The involvement of heme oxygenase-1 (HO-1) was also investigated.

METHODS

Male Sprague Dawley rats were allocated to receive HS/RES, HS/RES plus iv cepharanthine or HS/RES plus cepharanthine plus the HO-1 activity inhibitor tin protoporphyrin (SnPP) and denoted as the HS/RES, HS/RES+CEP, and HS/RES+CEP+SnPP group, respectively. HS/RES was achieved by blood drawing to lower mean arterial pressure (40-45 mmHg for 60 min) followed by shed blood/saline mixtures re-infusion. The rats were monitored for another 5h before sacrifice.

RESULTS

Arterial blood gas, lung permeability and histologic assays (including histopathology, neutrophil infiltration, and lung water content) confirmed that HS/RES induced significant lung injury. Significant increases in pulmonary levels of tumor necrosis factor-α, interleukin-1β, interleukin-6, prostaglandin E2 and cyclooxygenase-2 confirmed that HS/RES induced a significant inflammatory response in the lungs. Cepharanthine significantly attenuated the pulmonary pro-inflammatory cytokine production and lung injury induced by HS/RES. However, the protective effects of cepharanthine were blocked by SnPP, the potent HO-1 activity inhibitor.

CONCLUSION

Cepharanthine significantly mitigates pro-inflammatory cytokine response in acute lung injury induced by HS/RES in rats. The mechanism may involve the HO-1 pathway.

Mangiferin Mitigates Gastric Ulcer in Ischemia/ Reperfused Rats: Involvement of PPAR-γ, NF-κB and Nrf2/HO-1 Signaling Pathways

Mangiferin (MF), a xanthonoid from Mangifera indica, has been proved to have antisecretory and antioxidant gastroprotective effects against different gastric ulcer models; however, its molecular mechanism has not been previously elucidated. Therefore, the aim of this study was to test its modulatory effect on several signaling pathways using the ischemia/reperfusion model for the first time. Animals were treated with MF, omeprazole (OMP), and the vehicle. The mechanistic studies revealed that MF mediated its gastroprotective effect partly via inducing the expression of Nrf2, HO-1 and PPAR-γ along with downregulating that of NF-κB. Surprisingly, the effect of MF, especially the high dose, exceeded that mediated by OMP except for Nrf2. The molecular results were reflected on the biomarkers measured, where the antioxidant effect of MF was manifested by increasing total antioxidant capacity and glutathione, besides normalizing malondialdehyde level. Additionally, MF decreased the I/R-induced nitric oxide elevation, an effect that was better than that of OMP. In the serum, MF, dose dependently, enhanced endothelial nitric oxide synthase, while reduced the inducible isoform. Regarding the anti-inflammatory effect of MF, it reduced serum level of IL-1β and sE-selectin, effects that were mirrored on the tissue level of myeloperoxidase, the neutrophil infiltration marker. In addition, MF possessed an antiapoptotic character evidenced by elevating Bcl-2 level and reducing that of caspase-3 in a dose related order. As a conclusion, the intimated gastroprotective mechanisms of MF are mediated, partially, by modulation of oxidative stress, inflammation and apoptosis possibly via the Nrf2/HO-1, PPAR-γ/NF-κB signaling pathways.

Protective mechanism of Panax notoginseng saponins on rat hemorrhagic shock model in recovery stage

To explore protective mechanism of Panax notoginseng saponins (PNS) on rat hemorrhagic shock model in recovery stage. 72 Wistar rats were selected and divided into control group, model group and PNS group with 24 rats in each group. 200 mg/kg PNS was injected intravenously at 60 min of hemorrhagic shock stage in PNS groups. Changes of endotoxin, MPO, IL-6, SOD, MDA and TNF α were observed at 30 and 120 min of recovery stage by ELISA; water content of lung and intestine was detected; HE staining was applied to observe morphological change of intestinal mucosa, kidney, liver and lung; western blot was used to detect intercellular adhesion molecule-1 (ICAM-1) level in lung tissue and intestine tissue. At 30 min and 120 min of recovery stage, MDA, MPO, endotoxin, TNF α and IL-6 levels significantly increased in model group compared with control group, however SOD level significantly decreased, the difference was statistically significant (P < 0.05); PNS dose-dependently decreased MDA, MPO, endotoxin, TNF α and IL-6 levels, and increased SOD level, which was statistically significant (P < 0.05); In results of water content detection, water content in lung tissue and intestine tissue was significantly higher than in control group, however, after being treated with PNS, the water content was significantly decreased; HE staining showed the morphologic change of lung tissue cells; Western blot showed that in lung tissue and intestine tissue, ICAM-1 level in model group was significantly higher than in control group, and it was lower in PNS group than in model group. PNS can increase SOD activity, decrease levels of MDA, endotoxin and MPO, decrease expression of TNF α and IL-6, and decrease water content in lung tissue and intestine tissue. Thus, PNS is protective to rat hemorrhagic shock model by anti oxidative stress and anti-inflammatory pathways, and ICAM-1 may play an important role in the mechanism.

Effects of dexmedetomidine pretreatment on heme oxygenase-1 expression and oxidative stress during one-lung ventilation

PURPOSE

This study aimed to explore effects of dexmedetomidine pretreatment on heme oxygenase-1 (HO-1) expression and oxidative stress during one-lung ventilation (OLV) in lung cancer patients.

METHODS

Fifty patients with lung carcinoma (ASA I-II, 40-65 years old, body mass index [BMI]<30 kg/m2) undergoing pulmonary lobectomy were enrolled. They were divided randomly into two equal groups before anaesthesia induction to receive either intravenous injection of 1 μg/kg dexmedetomidine for 20 min (Dexmedetomidine) or not (Control).

RESULTS

The results showed no difference in heart rate (HR), mean arterial pressure (MAP) and bispectral index (BIS) between the two groups, as well as liquid intake and output volume (LIO), duration of OLV and time from surgery beginning to excision of pathological tissues (P>0.05). Levels of tumor necrosis factor (TNF-α) and malondialdehyde (MDA) in Dexmedetomidine group were lower than that of Control at OLV 60 and 90 (P<0.05). Superoxide dismutase (SOD) activity and the expression level of HO-1 were higher in Dexmedetomidine group than in Control (P<0.05).

CONCLUSIONS

Dexmedetomidine pretreatment could upregulated expression of HO-1 in lung tissue and reduce oxidative stress and inflammation during OLV. Thus dexmedetomidine played a role in protecting lung injury by promoting HO-1 expression.

Anti-inflammatory effects of β-hydroxyisovalerylshikonin in BV2 microglia are mediated through suppression of the PI3K/Akt/NF-kB pathway and activation of the Nrf2/HO-1 pathway

In the present study, we investigated whether β-hydroxyisovalerylshikonin (β-HIVS) affects the production of proinflammatory mediators such as nitric oxide (NO) and prostaglandin E2 (PGE2) in BV2 microglial cells. Our data showed that β-HIVS inhibited secretion of NO and PGE2 and downregulated expression of their main regulatory genes, inducible NO synthesis (iNOS) and cyclooxygenase-2 (COX-2). β-HIVS also reduced the LPS-induced DNA-binding activity of nuclear factor-κB (NF-κB) by suppressing nuclear translocation of the NF-κB subunits and inhibiting the degradation and phosphorylation of IκBα. Furthermore, an NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), attenuated LPS-stimulated iNOS and COX-2 expression, suggesting that NF-κB inhibition is a main effector in the expression of iNOS and COX-2. We also found that LPS-induced NF-κB activation is regulated through inhibition of PI3K/Akt phosphorylation in response to β-HIVS. Additionally, β-HIVS caused the induction of heme oxygenase-1 (HO-1) via upregulation of nuclear factor-erythroid 2-related factor 2 (Nrf2), both of which are involved in the secretion of proinflammatory mediators such as NO and PGE2. Taken together, our data indicate that β-HIVS diminishes the proinflammatory mediators NO and PGE2 and the expression of their regulatory genes, iNOS and COX-2, in LPS-stimulated BV2 microglial cells by inhibiting PI3K/Akt-dependent NF-κB activation and inducing Nrf2-mediated HO-1 expression.

Antrodia salmonea inhibits TNF-α-induced angiogenesis and atherogenesis in human endothelial cells through the down-regulation of NF-κB and up-regulation of Nrf2 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Antrodia salmonea (AS) is known as a traditional Chinese medicine, but very few biological activities have been reported.

MATERIALS AND METHODS

The present study was aimed to investigate the anti-angiogenic and anti-atherosclerotic potential of the fermented culture broth of AS against tumor necrosis factor-α (TNF-α)-stimulated human endothelial (EA.hy 926) cells.

RESULTS

The non-cytotoxic concentrations of AS significantly inhibited TNF-α-induced migration/invasion and capillary-like tube formation in EA.hy 926 cells. Furthermore, AS suppressed TNF-α-induced activity and expression of matrix metalloproteinase-9 (MMP-9), and cell-surface expression of intercellular adhesion molecule-1 (ICAM-1), which was associated with abridged adhesion of U937 leukocytes to endothelial cells. Moreover, AS significantly down-regulated TNF-α-induced nuclear translocation and transcriptional activation of nuclear factor κB (NF-κB) followed by suppression of I-κB degradation and phosphorylation of I-κB kinase-α (IKKα). Notably, the protective effect of AS was directly correlated with the increased expression of hemeoxygenase-1 (HO-1) and γ-glutamylcysteine synthetase (γ-GCLC), which was reasoned by nuclear translocation and transactivation of NF-E2 related factor-2 (Nrf2)/antioxidant response element (ARE). Furthermore, HO-1 knockdown by HO-1-specific shRNA diminished the protective effects of AS on TNF-α-stimulated invasion, tube formation, and U937 adhesion in EA.hy 926 cells.

CONCLUSIONS

Taken together, these results suggest that Antrodia salmonea may be useful for the prevention of angiogenesis and atherosclerosis.

Pharmacologic suppression of inflammation by a diphenyldifluoroketone, EF24, in a rat model of fixed-volume hemorrhage improves survival

An exaggerated release of proinflammatory cytokines and accompanying inflammation contributes to the development of multiple organ failure after hemorrhagic shock. Here, we tested the nuclear factor (NF) κ-light-chain-enhancer of activated B cell (NF-κB)-mediated transcriptional control of inflammatory pathways as a target in the management of hemorrhage-induced inflammation. We performed a study in a rat model of fixed-volume hemorrhage to investigate the anti-inflammatory effects of the diphenyldifluoroketone EF24 [3,5-bis(2-fluorobenzylidene)piperidin-4-one], an NF-κB inhibitor, in lung tissue. EF24 treatment (0.4 mg/kg) significantly prevented the upregulation of inflammatory biomarkers in rats subjected to 50% hemorrhage and preserved the pulmonary histology in hemorrhaged rats. The lung tissue from treated rats showed marked suppression of the hemorrhage-mediated induction of Toll-like receptor 4, phospho-p65 NF-κB, inducible nitric-oxide synthase, heme oxygenase-1, and cyclooxygenase-2 (COX-2). The hemorrhage-induced COX-2 activity was also significantly inhibited by the EF24 treatment. At the same time, EF24 induced nuclear factor (erythroid-derived 2)-like 2-mediated protective mechanisms against oxidative stress. EF24 also reduced hemorrhage-induced lung myeloperoxidase activity. The plasma levels of proinflammatory tumor necrosis factor-α, interleukin (IL)-6, IL-1α, and IL-1β were lower in EF24-treated rats than in untreated rats. Moreover, there was a significant reduction in the pulmonary expression of high-mobility group B1 protein. These biochemical effects were accompanied by a significant improvement in the survival of rats administered with EF24 as compared with the rats receiving vehicle control (P < 0.05). Overall, the results suggest that EF24 attenuates hemorrhage-induced inflammation and could serve as a salutary anti-inflammatory agent in resuscitation strategies.

Targeting the redox balance in inflammatory skin conditions

Reactive oxygen species (ROS) can be both beneficial and deleterious. Under normal physiological conditions, ROS production is tightly regulated, and ROS participate in both pathogen defense and cellular signaling. However, insufficient ROS detoxification or ROS overproduction generates oxidative stress, resulting in cellular damage. Oxidative stress has been linked to various inflammatory diseases. Inflammation is an essential response in the protection against injurious insults and thus important at the onset of wound healing. However, hampered resolution of inflammation can result in a chronic, exaggerated response with additional tissue damage. In the pathogenesis of several inflammatory skin conditions, e.g., sunburn and psoriasis, inflammatory-mediated tissue damage is central. The prolonged release of excess ROS in the skin can aggravate inflammatory injury and promote chronic inflammation. The cellular redox balance is therefore tightly regulated by several (enzymatic) antioxidants and pro-oxidants; however, in case of chronic inflammation, the antioxidant system may be depleted, and prolonged oxidative stress occurs. Due to the central role of ROS in inflammatory pathologies, restoring the redox balance forms an innovative therapeutic target in the development of new strategies for treating inflammatory skin conditions. Nevertheless, the clinical use of antioxidant-related therapies is still in its infancy.

Proinflammatory responses of heme in alveolar macrophages: repercussion in lung hemorrhagic episodes

Clinical and experimental observations have supported the notion that free heme released during hemorrhagic and hemolytic episodes may have a major role in lung inflammation. With alveolar macrophages (AM) being the main line of defense in lung environments, the influence of free heme on AM activity and function was investigated. We observed that heme in a concentration range found during hemolytic episodes (3–30 μM) elicits AM to present a proinflammatory profile, stimulating reactive oxygen species (ROS) and nitric oxide (NO) generation and inducing IL-1β, IL-6, and IL-10 secretion. ROS production is NADPH oxidase-dependent, being inhibited by DPI and apocynin, and involves p47 subunit phosphorylation. Furthermore, heme induces NF-κB nuclear translocation, iNOS, and also HO-1 expression. Moreover, AM stimulated with free heme show enhanced phagocytic and bactericidal activities. Taken together, the data support a dual role for heme in the inflammatory response associated with lung hemorrhage, acting as a proinflammatory molecule that can either act as both an adjuvant of the innate immunity and as an amplifier of the inflammatory response, leading tissue injury. The understanding of heme effects on pulmonary inflammatory processes can lead to the development of new strategies to ameliorate tissue damage associated with hemorrhagic episodes.

Transient increase of free iron in rat livers following hemorrhagic-traumatic shock and reperfusion is independent of heme oxygenase 1 upregulation

Hemorrhagic-traumatic shock (HTS) followed by reperfusion induces heme oxygenase (HO) 1. Free iron (Fe2+) may cause oxidative stress, if not adequately sequestered. We aimed to characterize HO-1-mediated effects on Fe2+ levels in liver and transferrin-bound iron (TFBI) in plasma following HTS, including laparotomy, bleeding, and inadequate and adequate reperfusion. Anesthetized rats showed upregulated HO-1 mRNA at 40 min after HTS, which was followed by increased HO activity at 3 h after shock. Fe2+ levels were transiently increased at 40 min after shock, a time point when HO activity was not affected yet. Levels of plasma TFBI were higher in HTS animals, showing the highest levels at 40 min after shock, and decreased thereafter. In addition, we modulated HO activity 6 h before HTS by administering an inhibitor (zinc-protoporphyrin IX) or an activator (hemin) of HO. At 18 h after HTS in all shock groups, HO activity was increased, the highest being in the hemin-pretreated group. The zinc-protoporphyrin IX-treated HTS animals showed increased HO-1 mRNA and Fe2+ levels in the liver compared with the untreated HTS animals. Transferrin-bound iron levels were affected by pharmacological modulation before shock. All animals undergoing HTS displayed increased TFBI levels after reperfusion; however, in animals pretreated with hemin, TFBI levels increased less. Our data indicate that increase in Fe2+ levels in liver and plasma early after HTS is not mediated by HO-1 upregulation, but possibly reflects an increased mobilization from internal iron stores or increased cell damage. Thus, upregulation of HO activity by hemin does not increase Fe2+ levels following HTS and reperfusion.

Heme oxygenase, inflammation, and fibrosis: the good, the bad, and the ugly?

Upon injury, prolonged inflammation and oxidative stress may cause pathological wound healing and fibrosis, leading to formation of excessive scar tissue. Fibrogenesis can occur in most organs and tissues and may ultimately lead to organ dysfunction and failure. The underlying mechanisms of pathological wound healing still remain unclear, and are considered to be multifactorial, but so far, no efficient anti-fibrotic therapies exist. Extra- and intracellular levels of free heme may be increased in a variety of pathological conditions due to release from hemoproteins. Free heme possesses pro-inflammatory and oxidative properties, and may act as a danger signal. Effects of free heme may be counteracted by heme-binding proteins or by heme degradation. Heme is degraded by heme oxygenase (HO) that exists as two isoforms: inducible HO-1 and constitutively expressed HO-2. HO generates the effector molecules biliverdin/bilirubin, carbon monoxide, and free iron/ferritin. HO deficiency in mouse and man leads to exaggerated inflammation following mild insults, and accumulating epidemiological and preclinical studies support the widely recognized notion of the cytoprotective, anti-oxidative, and anti-inflammatory effects of the activity of the HO system and its effector molecules. In this review, we address the potential effects of targeted HO-1 induction or administration of HO-effector molecules as therapeutic targets in fibrotic conditions to counteract inflammatory and oxidative insults. This is exemplified by various clinically relevant conditions, such as hypertrophic scarring, chronic inflammatory liver disease, chronic pancreatitis, and chronic graft rejection in transplantation.

Attenuation of fatty liver and prevention of hypercholesterolemia by extract of Curcuma longa through regulating the expression of CYP7A1, LDL-receptor, HO-1, and HMG-CoA reductase

The extract of Curcuma longa, better known as turmeric, was orally administered to experimental rats that were fed a high-cholesterol diet to investigate whether it could regulate plasma lipids and cholesterol levels and possibly improve hepatic conditions. With turmeric supplements, rats showed a significant decrease in total plasma cholesterol and low-density lipoprotein cholesterol but an increase in high-density lipoprotein cholesterol when compared with rats that were fed a high-cholesterol diet alone. Fatty liver developed in hypercholesterolemic rats with the high-cholesterol diet treatment, and this condition was markedly improved when rats were provided with turmeric supplements at 100 mg/kg or 300 mg/kg of body mass. The turmeric treatment resulted in a significant decrease in the total amount of hepatic lipid. Histological staining of liver tissues with Sudan III and hematoxylin showed that rats fed with a high-cholesterol diet alone had more and larger granular fat bodies than rats having turmeric extract supplementation in their high-cholesterol diet. Reverse-transcription polymerase chain reaction was used to assess the expression levels of enzymes involved in fat metabolism and cellular homeostasis in experimental rat livers. The results showed that rats fed a high-cholesterol diet supplemented with turmeric extract had a significant increase in the expression of cholesterol 7 α-hydroxylase, hemeoxygenase 1, and low-density lipoprotein receptors but a significant decrease in 3-hydroxy-3-methyl-glutaryl-CoA reductase level when compared with rats fed a normal or high-cholesterol diet, showing that turmeric prevents hypercholesterolemia and the formation of fatty liver by the modulation of expressions of enzymes that are important to cholesterol metabolism.

PRACTICAL APPLICATION

  Turmeric may be considered a functional food for regulating plasma cholesterol levels and preventing the development of fatty liver in people who frequently consume a high-cholesterol diet.

Dual protective role of HO-1 in transplanted liver grafts: A review of experimental and clinical studies

Liver transplantation is considered as the most effective treatment for end-stage liver disease. However, serious complications still exist, particularly in two aspects: ischemia and subsequent reperfusion of the liver, causing postoperative hepatic dysfunction and even failure; and acute and chronic graft rejections, affecting the allograft survival. Heme oxygenase (HO), a stress-response protein, is believed to exert a protective function on both the development of ischemia-reperfusion injury (IRI) and graft rejection. In this review of current researches on allograft protection, we focused on the HO-1. We conjecture that HO-1 may link these two main factors affecting the prognosis of liver transplantations. In this review, the following aspects were emphasized: the basic biological functions of HO-1, its roles in IRI and allograft rejection, as well as methods to induce HO-1 and the prospects of a therapeutic application of HO-1 in liver transplantation.

Heme oxygenase-1: a novel therapeutic target for gastrointestinal diseases

Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in the catabolism of heme, followed by production of biliverdin, free iron and carbon monoxide (CO). HO-1 is a stress-responsive protein induced by various oxidative agents. Recent studies demonstrate that the expression of HO-1 in response to different inflammatory mediators may contribute to the resolution of inflammation and has protective effects in several organs against oxidative injury. Although the mechanism underlying the anti-inflammatory actions of HO-1 remains poorly defined, both CO and biliverdin/bilirubin have been implicated in this response. In the gastrointestinal tract, HO-1 is shown to be transcriptionally induced in response to oxidative stress, preconditioning and acute inflammation. Recent studies suggest that the induction of HO-1 expression plays a critical protective role in intestinal damage models induced by ischemia-reperfusion, indomethacin, lipopolysaccharide-associated sepsis, trinitrobenzene sulfonic acid, and dextran sulfate sodium, indicating that activation of HO-1 may act as an endogenous defensive mechanism to reduce inflammation and tissue injury in the gastrointestinal tract. In addition, CO derived from HO-1 is shown to be involved in the regulation in gastro-intestinal motility. These in vitro and in vivo data suggest that HO-1 may be a novel therapeutic target in patients with gastrointestinal diseases.

Abnormal modulation of cell protective systems in response to ischemic/reperfusion injury is important in the development of mouse sickle cell hepatopathy

BACKGROUND

Sickle cell disease, a genetic red cell disorder inherited in an autosomal recessive manner, occurs throughout the world. Hepatic dysfunction and liver damage may be present in sickle cell disease, but the pathogenesis of these conditions is only partially understood.

DESIGN AND METHODS

Transgenic mice with sickle cell disease (SAD mice) and wild-type mice were exposed to an ischemic/reperfusion stress. The following parameters were evaluated: hematologic profile, transaminase and bilirubin levels, liver histopathology, and mRNA levels of nuclear factor-κB p65, endothelial nitric oxide synthase, inducible nitric oxide synthase, heme oxygenase-1 and phosphodiesterase-1, -2, -3, and -4 genes in hepatocytes obtained by laser-capture microdissection. Immunoblotting was used to analyze the expression of the following proteins: nuclear factor-κB p65 and phospho-nuclear factor-κB p65, heme oxygenase-1, biliverdin reductase, heat shock protein-70, heat shock protein-27 and peroxiredoxin-6. A subgroup of SAD mice was treated with the phosphodiesterase-4 inhibitor rolipram (30 mg/Kg/day by gavage) during the ischemic/reperfusion protocol.

RESULTS

In SAD mice the ischemic/reperfusion stress induced liver damage compatible with sickle cell disease hepatopathy, which was associated with: (i) lack of hypoxia-induced nuclear factor-κB p65 activation; (ii) imbalance in the endothelial/inducible nitric oxide synthase response to ischemic/reperfusion stress; (iii) lack of hypoxia-induced increased expression of heme oxygenase-1/biliverdin reductase paralleled by a compensatory increased expression of heat shock proteins 70 and 27 and peroxiredoxin-6; and (iv) up-regulation of the phosphodiesterase-1, -2, -3, and -4 genes. In SAD mice the phosphodiesterase-4 inhibitor rolipram attenuated the ischemic/reperfusion-related microcirculatory dysfunction, reduced the inflammatory cell infiltration and induced the heme oxygenase-1/biliverdin reductase cytoprotective systems.

CONCLUSIONS

In SAD mice, sickle cell hepatopathy is associated with perturbed nuclear factor-κB p65 signaling with an imbalance of endothelial/inducible nitric oxide synthase levels, lack of heme oxygenase-1/biliverdin reductase expression and up-regulation of two novel cytoprotective systems: heat shock protein-27 and peroxiredoxin-6.

Complement factor 3 deficiency attenuates hemorrhagic shock-related hepatic injury and systemic inflammatory response syndrome

Although complement activation is known to occur in the setting of severe hemorrhagic shock and tissue trauma (HS/T), the extent to which complement drives the initial inflammatory response and end-organ damage is uncertain. In this study, complement factor 3-deficient (C3(-/-)) mice and wild-type control mice were subjected to 1.5-h hemorrhagic shock, bilateral femur fracture, and soft tissue injury, followed by 4.5-h resuscitation (HS/T). C57BL/6 mice were also given 15 U of cobra venom factor (CVF) or phosphate-buffered saline injected intraperitoneally, followed by HS/T 24 h later. The results showed that HS/T resulted in C3 consumption in wild-type mice and C3 deposition in injured livers. C3(-/-) mice had significantly lower serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and circulating DNA levels, together with much lower circulating interleukin (IL)-6, IL-10, and high-mobility group box 1 (HMGB1) levels. Temporary C3 depletion by CVF preconditioning also led to reduced transaminases and a blunted cytokine release. C3(-/-) mice displayed well-preserved hepatic structure. C3(-/-) mice subjected to HS/T had higher levels of heme oxygenase-1, which has been associated with tissue protection in HS models. Our data indicate that complement activation contributes to inflammatory pathways and liver damage in HS/T. This suggests that targeting complement activation in the setting of severe injury could be useful.

Protective effect of carbon monoxide inhalation on lung injury after hemorrhagic shock/resuscitation in rats

BACKGROUND

Hemorrhagic shock and resuscitation (HSR) induces pulmonary inflammation that leads to acute lung injury. Carbon monoxide (CO), a by-product of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. The aim of this study was to examine the effects of CO inhalation at low concentration on lung injury induced by HSR in rats.

METHODS

Rats were subjected to HSR by bleeding to achieve mean arterial pressure of 30 mm Hg for 60 minutes followed by resuscitation with shed blood and saline as needed to restore blood pressure. HSR animals were either maintained in room air or were exposed to CO at 250 ppm for 1 hour before and 3 hours after HSR.

RESULTS

HSR caused an increase in the DNA binding activity of nuclear factor-kappaB and activator protein-1 in the lung followed by the up-regulation of pulmonary gene expression of tumor necrosis factor-alpha, inducible nitric oxide synthase, and interleukin (IL)-10. HSR also resulted in an increase in myeloperoxidase activity and wet weight to dry weight ratio in the lung, and more prominent histopathologic changes including congestion, edema, cellular infiltration, and hemorrhage. In contrast, CO inhalation significantly ameliorated these inflammatory events as judged by fewer histologic changes, less up-regulation of inflammatory mediators, and less activation of nuclear factor-kappaB and activator protein-1. Interestingly, the protective effects against lung injury afforded by CO were associated with further increases in mRNA expression of IL-10 in the lung.

CONCLUSIONS

These findings suggest that inhaled CO at a low concentration ameliorated HSR-induced lung injury and attenuated inflammatory cascades by up-regulation of anti-inflammatory IL-10.

Bach1 gene ablation reduces steatohepatitis in mouse MCD diet model

Bach1 is a transcriptional repressor of heme oxygenase-1 (HO-1, a.k.a. HSP-32), which is an inducible enzyme and has anti-oxidation/anti-inflammatory properties shown in various models of organ injuries. Since oxidative stress plays a pivotal role in the pathogenesis of nonalcoholic steatohepatitis (NASH), HO-1 induction would be expected to prevent the development of NASH. In this study, we investigated the influence of Bach1 ablation in mice on the progression of NASH in methionine-choline deficient (MCD) diet model. Bach1 ablation resulted in significant induction of HO-1 mRNA and its activity in the liver. When fed MCD diet, Bach1(-/-) mice exhibited negligible hepatic steatosis compared to pronounced steatohepatitis in wild type mice with 6-fold increase in hepatic triglyceride content. Whereas feeding of MCD diet decreased mRNA expressions of peroxisome proliferator-activated receptor (PPAR) α and microsomal triglyceride transfer protein (MTP) in wild type mice, there were no change in Bach1(-/-) mice. In addition, hepatic concentration of malondialdehyde (MDA), a biomarker for oxidative stress as well as plasma alanine aminotransferase (ALT) was significantly lower in Bach1(-/-) mice. These findings suggest that Bach1 ablation exerts hepatoprotective effect against steatohepatitis presumably via HO-1 induction and may be a potential therapeutic target.