Upregulation Of Heme Oxygenase-1 Research Articles

Heme Oxygenase-1 Protects Bone Marrow Mesenchymal Stem Cells Against Iron Overload through Decreasing ROS and Promoting IL-10 Generation

Background:Iron overload caused by frequent transfusions of suspended red blood cells which is of major concern in hematological disease. Heme oxygenase-1(HO-1) is well known as a crucial factor to cells against oxidative stress. In this study, significant upregulation of HO-1 was observed in bone marrow mesenchymal stem cells (BMMSCs) in the early phase of IO and predicted good prognosis in mice.Aim: Given that the role of HO-1 in protecting (BMMSCs) against damage from IO was still unknown. In the study, we investigated the effects and mechanisms of iron overload-related ROS by inducing IL-10 by regulating HO-1.METHODS:Male C57BL/6Ly5.2 (Ly45.2) mice were housed under specific pathogen-free conditions and allowed to acclimate for 2 weeks before experiments. The mice were housed (5 individuals per cage) and used at a weight of approximately 20.0 g. Thirty male mice were recipient mice, and another five were competitive mice. The thirty-five mice were randomly divided into four groups: (a) a control group; (b) an IO group (25 mg/ml); (c) an IO + hemin group and (d) an IO + ZnPP group. The depositions of iron in the liver, spleen and BM were assessed using HE staining and BM iron staining. Then, the expression of HO-1 and IL-10 were examined by Western blotting and q-PCR. Cell proliferation was measured by CCK-8 assay. The quantity of Ferritin, Serum iron, Hepcidin and IL-10 in the blood serum from iron overload cell were detected by ELISA in mouse model and iron overload patients. Finally, the levels of apoptotic rate, intracellular ROS and labile iron pool (LIP) were analyzed by flow cytometer.Result :We found that HO-1 was upregulated in the excess iron culture of BMMSCs in the early phase. Meanwhile, the apoptosis rate of IO BMMSCs was increased by 3.0 times compared with that of CON group. On the contrary, the apoptotic rate of BMMSCs down-regulated by transcription of si-HO-1 virus increased by 7.12 times compared to the CON group. In addition, the apoptosis rate of HO-1 overexpressing BMMSCs was significantly decreased in BM-1 virus transfected with HO-1 virus. Next, we also observed LIP in IO BMMSCs transfected with HO-1 virus was significantly lower than IO BMMSCs in un-transfected group. It suggested that HO-1 up-regulated the BMMSCs was protected from IO damage by decreasing intracellular iron content in vitro.To get an insight into the mechanism involved in cells protection from IO by HO-1 upregulation. We further explore production of ROS and secrection of IL10. As HO-1 was reported to have ability to reduce ROS, and IL-10 could promote excretion of intracellular iron. The results showed the ROS level in IO BMMSC was improved by 5.94 times compared with that of CON group, and the level of ROS in IO BMMSCs transcribed with si-HO-1 and HO-1 virus increased by 6.18 and 4.53 times, respectively. And IL-10 was increased significantly in the HO-1 up-regulated group.Next, we used U0126 (an ERK pathway inhibitor) to co-culture with IO BMMSCs that transcribed HO-1 virus. We observed the secretion of ferritin and the expression of IL-10 were consistent with the BMMSCs concentration changed. In vivo, we found that the serum iron and ferritin levels in the peripheral blood of IO mice were reduced by 1.92 and 1.3 times through ELISA analysis. The levels of IL-10 and ferritin were detected by ELISA. The results of deposition detection in bone marrow were consistent with the in vitro model. Finally, from November 2015 to December 2016, 12 patients diagnosed iron overload were enrolled. Including 6 males and 6 females, aged 44 to 77 years old. By q-PCR, we also found that iron overload in BMMSCs with high expression of HO-1 and IL-10 was reduced in serum ferritin after deferoxamine treatment. Therefore, we hypothesized that HO-1 overexpression of iron overload patients with better prognosis.Conclusions: we hypothesized that HO-1 overexpression of iron overload patients with better prognosis. The results of this study allow for further study of mechanisms of IO-related disease and provide new therapeutic targets for the treatment of IO patients. DisclosuresNo relevant conflicts of interest to declare.

Up-regulation of heme oxygenase-1 by celastrol alleviates oxidative stress and vascular calcification in chronic kidney disease

Vascular calcification is very commonly observed in patients with chronic kidney disease (CKD), but there is no efficient therapy available. Oxidative stress plays critical roles in the progression of vascular calcification. Celastrol (Cel), a natural constituent derived from Chinese herbals, exhibits anti-oxidative stress activity. Here, we investigated the effect of celastrol on vascular calcification using vascular smooth muscle cells (VSMCs), arterial rings and CKD rats. Alizarin red staining and gene expression analysis showed that Cel dose-dependently inhibited rat VSMC calcification and osteogenic differentiation. Similarly, ex vivo study revealed that Cel inhibited calcification of rat and human arterial rings. In addition, micro-computed tomography, alizarin red staining and calcium content analysis confirmed that Cel inhibited aortic calcification in CKD rats. Interestingly, Cel treatment increased the mRNA and protein levels of heme oxygenase-1 (HMOX-1), and reduced the levels of reactive oxygen species (ROS) in VSMCs. Furthermore, both pharmacological inhibition of HMOX-1 and knockdown of HMOX-1 by siRNA independently counteracted the inhibitory effect of Cel on vascular calcification. Moreover, knockdown of HMOX-1 prevented Cel treatment-mediated reduction in ROS levels. Finally, Cel treatment reduced Vitamin D3-induced aortic calcification in mice and this effect was blocked by HMOX-1 inhibitor ZnPP9. Collectively, our results suggest that up-regulation of HMOX-1 is required for the inhibitory effect of Cel on vascular calcification. Modulation of HMOX-1 may provide a novel strategy for the treatment of vascular calcification in CKD.

VHL regulates the sensitivity of clear cell renal cell carcinoma to SIRT4-mediated metabolic stress via HIF-1\u03b1/HO-1 pathway

Clear cell renal cell carcinomas (ccRCC) reprogram carbon metabolism responses to hypoxia, thereby promoting utilization of glutamine. Recently, sirtuin 4 (SIRT4), a novel molecular has turned out to be related to alternating glutamine metabolism and modulating the tumor microenvironment. However, the role of SIRT4 in ccRCC remains poorly understood. Here, we illustrated that the expression of SIRT4 is markedly reduced in cancerous tissues, and closely associated with malignancy stage, grade, and prognosis. In ccRCC cells, SIRT4 exerted its proapoptotic activity through enhancing intracellular reactive oxygen species (ROS). Heme oxygenase-1 (HO-1) is part of an endogenous defense system against oxidative stress. Nevertheless, overexpression of SIRT4 hindered the upregulation of HO-1 in von Hippel–Lindau (VHL)-proficient cells and repressed its expression in VHL-deficient cells. This discrepancy indicated that competent VHL withstands the inhibitory role of SIRT4 on HIF-1α/HO-1. Functionally, overexpression of HO-1 counteracted the promotional effects of SIRT4 on ROS accumulation and apoptosis. Mechanistically, SIRT4 modulates ROS and HO-1 expression via accommodating p38-MAPK phosphorylation. By contrast, downregulation of p38-MAPK by SB203580 decreased intracellular ROS level and enhanced the expression of HO-1. Collectively, this work revealed a potential role for SIRT4 in the stimulation of ROS and the modulation of apoptosis. SIRT4/HO-1 may act as a potential therapeutic target, especially in VHL-deficient ccRCCs.

AICAR decreases acute lung injury by phosphorylating AMPK and upregulating heme oxygenase-1.

We investigated the mechanisms by which N1-(β-d-ribofuranosyl)-5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an activator of AMP-activated protein kinase (AMPK), decreases lung injury and mortality when administered to mice post exposure to bromine gas (Br2). We exposed male C57BL/6 mice and heme oxygenase-1 (HO-1)-deficient (HO-1-/-) and corresponding wild-type (WT) littermate mice to Br2 (600 ppm for 45 or 30 min, respectively) in environmental chambers and returned them to room air. AICAR was administered 6 h post exposure (10 mg·kg-1, intraperitoneal). We assessed survival, indices of lung injury, high mobility group box 1 (HMGB1) in the plasma, HO-1 levels in lung tissues and phosphorylation of AMPK and its upstream liver kinase B1 (LKB1). Rat alveolar type II epithelial (L2) cells and human club-like epithelial (H441) cells were also exposed to Br2 (100 ppm for 10 min). After 24 h we measured apoptosis and necrosis, AMPK and LKB1 phosphorylation, and HO-1 expression. There was a marked downregulation of phosphorylated AMPK and LKB1 in lung tissues and in L2 and H441 cells post exposure. AICAR increased survival in C57BL/6 but not in HO-1-/- mice. In WT mice, AICAR decreased lung injury and restored phosphorylated AMPK and phosphorylated LKB1 to control levels and increased HO-1 levels in both lung tissues and cells exposed to Br2. Treatment of L2 and H441 cells with small interfering RNAs against nuclear factor erythroid 2-related factor 2 or HO-1 abrogated the protective effects of AICAR. Our data indicate that the primary mechanism for the protective action of AICAR in toxic gas injury is the upregulation of lung HO-1 levels.

3-Methyladenine but not antioxidants to overcome BACH2-mediated bortezomib resistance in mantle cell lymphoma

BackgroundBortezomib (BTZ) is an inhibitor of the proteasome that has been used to treat patients with mantle cell lymphoma (MCL), but the resistance to BTZ in clinical cases remains a major drawback. BACH2 is a lymphoid-specific transcription repressor recognized as a tumor suppressor in MCL. Reduced BACH2 levels contribute to BTZ resistance; however, the molecular events underlying BACH2-mediated BTZ resistance are largely unclear.MethodsWe silenced BACH2 in MCL cells using a lentiviral shRNA-mediated knockdown system. Bioinformatic, real-time RT-PCR, immunoblotting and a series of functional assays were performed to describe the molecular mechanisms underlying BTZ resistance in MCL. The therapeutic effects of chemicals were evaluated on numerous cellular and molecular processes in resistant MCL cell lines and xenografts.ResultsIn resistant cells, BTZ-triggered mild oxidative stress induced a strong activation of PI3K-AKT signaling, which further blocked nuclear translocation of BACH2. Defective nuclear translocation of BACH2 or silencing BACH2 removed its transcriptional repression on HMOX1, leading to upregulation of heme oxygenase-1 (HO-1). Increased HO-1 further maintained reactive oxygen species (ROS) within a minimal tumor-promoting level and enhanced cytoprotective autophagy. Interestingly, although mild increase in ROS exhibited a pro-tumorigenic effect on resistant cells, simply blocking ROS by antioxidants did not lead to cell death but aggravated BTZ resistance via stabilizing BACH1, the other member of BACH family. Instead, 3-methyladenine (3-MA), a dual inhibitor to suppress PI3K signaling and autophagosome formation, sensitized resistant MCL cells to BTZ, both in vitro and in vivo.ConclusionOur results dissected the interconnected molecular network in resistant MCL cells in which 3-MA represents an effective therapeutic strategy to overcome BTZ resistance. Notably, BACH1 and BACH2, albeit from the same family, are likely to play opposite roles in pathogenesis and progression of MCL.

Glucose-impaired Corneal Re-epithelialization Is Promoted by a Novel Derivate of Dimethyl Fumarate.

Glucose induces corneal epithelial dysfunctions characterized by delayed wound repair. Nuclear erythroid 2-related factor 2 (Nrf2) mediates cell protection mechanisms even through the Heme oxygenase-1 (HO-1) up-regulation. Here, we synthesized new HO-1 inducers by modifying dimethyl fumarate (DMF) and used docking studies to select VP13/126 as a promising compound with the best binding energy to Kelch-like ECH-associated protein 1 (keap1), which is the the regulator of Nrf2 nuclear translocation. We verified if VP13/126 protects SIRC cells from hyperglycemia compared to DMF. SIRC were cultured in normal (5 mM) or high glucose (25 mM, HG) in presence of DMF (1–25 μM) or VP13/126 (0.1–5 μM) with or without ERK1/2 inhibitor PD98059 (15 μM). VP13/126 was more effective than DMF in the prevention of HG-induced reduction of cell viability and proliferation. Reduction of wound closure induced by HG was similarly counteracted by 1 μM VP13/126 and 10 μM DMF. VP13/126 strongly increased phospho/total ERK1/2 and restored HO-1 protein in HG-treated SIRC; these effects are completely counteracted by PD98059. Moreover, high-content screening analysis showed a higher rate of Nrf2 nuclear translocation induced by VP13/126 than DMF in HG-stimulated SIRC. These data indicate that VP13/126 exerts remarkable pro-survival properties in HG-stimulated SIRC, promoting the Nrf2/HO-1 axis.

5-Aminolevulinic Acid as a Novel Therapeutic for Inflammatory Bowel Disease.

5-Aminolevulinic acid (5-ALA) is a naturally occurring nonprotein amino acid licensed as an optical imaging agent for the treatment of gliomas. In recent years, 5-ALA has been shown to possess anti-inflammatory and immunoregulatory properties through upregulation of heme oxygenase-1 via enhancement of porphyrin, indicating that it may be beneficial for the treatment of inflammatory conditions. This study systematically examines 5-ALA for use in inflammatory bowel disease (IBD). Firstly, the ex vivo colonic stability and permeability of 5-ALA was assessed using human and mouse fluid and tissue. Secondly, the in vivo efficacy of 5-ALA, in the presence of sodium ferrous citrate, was investigated via the oral and intracolonic route in an acute DSS colitis mouse model of IBD. Results showed that 5-ALA was stable in mouse and human colon fluid, as well as in colon tissue. 5-ALA showed more tissue restricted pharmacokinetics when exposed to human colonic tissue. In vivo dosing demonstrated significantly improved colonic inflammation, increased local heme oxygenase-1 levels, and decreased concentrations of proinflammatory cytokines TNF-α, IL-6, and IL-1β in both plasma and colonic tissue. These effects were superior to that measured concurrently with established anti-inflammatory treatments, ciclosporin and 5-aminosalicylic acid (mesalazine). As such, 5-ALA represents a promising addition to the IBD armamentarium, with potential for targeted colonic delivery.

Protective effects of upregulated HO-1 gene against the apoptosis of human retinal pigment epithelial cells in vitro.

To investigate the protective effect of heme oxygenase-1 (HO-1) against H2O2-induced apoptosis in human ARPE-19 cells. The lentiviral vector expressing HO-1 was prepared and transfected into apoptotic ARPE-19 cells induced by H2O2. Functional experiments including cell counting kit-8 (CCK-8) assay, flow cytometry (FCM) and mitochondrial membrane potential assay were conducted. The ultrastructure of ARPE-19 cells was observed using transmission electron microscope (TEM). It was found that exogenous HO-1 significantly ameliorated H2O2-induced loss of cell viability, apoptosis and intracellular levels of reactive oxygen species (ROS) in ARPE-19 cells. The overexpression of HO-1 facilitated the transfer of nuclear factor erythroid-2-related factor 2 (Nrf2) from cytoplasm to nucleus, which in turn upregualted expressions HO-1 and B-cell lymphoma-2 (Bcl-2). Furthermore, HO-1 upregulation further inhibited H2O2-induced release of cysteinyl aspartate specific proteinase-3 (caspase-3). Exogenous HO-1 protect ARPE-19 cells against H2O2-induced oxidative stress by regulating the expressions of Nrf2, HO-1, Bcl-2, and caspase-3.

Anti-inflammatory and Antioxidant Effects of Pluchea indica Leaf Extract in TNF-α-Induced Human Endothelial Cells

Pluchea indica is a shrub plant found in mangrove forests. The leaves are consumed as food and herbal tea and exhibit various biological effects, such as antioxidant and anti-inflammatory activities, in macrophages and animal models. However, the inhibitory activity of P. indica leaf extract on vascular inflammation remains unknown. Therefore, this study investigated the effect of an ethanol extract from P. indica herbal tea leaves (PIE) on tumor necrosis factor-α (TNF-α)-induced human vascular endothelial EA.hy926 cells. The cytotoxic effect of PIE was determined by thiazolyl blue tetrazolium bromide assays. PIE at concentrations of 12.5 - 50 µg/mL did not show significant cytotoxicity, whereas PIE at concentrations ≥ 100 µg/mL decreased cell viability. PIE inhibited the production of reactive oxygen species (ROS) in TNF-α-stimulated endothelial cells. To evaluate the PIE’s anti-vascular inflammatory activity, the protein expression of cell adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), was determined by western blot. PIE significantly decreased TNF-α-induced ICAM-1 and VCAM-1 expression in a concentration-dependent manner. Furthermore, PIE upregulated heme oxygenase-1 (HO-1) in a concentration- and time-dependent manner. Inhibiting the activity of HO-1 by tin protoporphyrin IX significantly blocked the suppressive effect of PIE on ICAM-1 but not VCAM-1 expression. Therefore, PIE exerts anti-inflammatory activity on vascular endothelial cells, at least in part, by suppressing ROS production and the induction of HO-1. The obtained data suggest that PIE is a promising substance for developing therapeutic agents or as an ingredient of functional food. HIGHLIGHTS Pluchea indica leaf extract (PIE) at non-toxic doses inhibited ICAM-1 and VCAM-1 in TNF-α-induced human vascular endothelial cells PIE suppressed the production of ROS in TNF-α-stimulated endothelial cells PIE exerts anti-inflammatory activity on vascular endothelial cells mediated partly through the upregulation of HO-1

Heme Oxygenase-1 Inhibition Potentiates the Effects of Nab-Paclitaxel-Gemcitabine and Modulates the Tumor Microenvironment in Pancreatic Ductal Adenocarcinoma.

Simple SummaryPancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies. Chemotherapy has had limited success in extending the life span of patients with advanced PDAC. Thus, new treatment approaches are needed. Heme oxygenase-1 (HO-1) is a key enzyme for the protection of cells against oxidative stress. Interestingly, HO-1 is overexpressed in several cancers, including PDAC. In the present study, our findings demonstrate the novel role of HO-1 in vivo in PDAC progression and in sensitizing tumor cells to cytotoxic chemotherapy by modulating the tumor microenvironment (TME).Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a poor prognosis. Tumor hypoxia plays an active role in promoting tumor progression, malignancy, and resistance to therapy in PDAC. We present evidence that nab-paclitaxel–gemcitabine (NPG) and/or a hypoxic tumor microenvironment (TME) up-regulate heme oxygenase-1 (HO-1), providing a survival advantage for tumors. Using PDAC cells in vitro and a PDAC mouse model, we found that NPG chemotherapy up-regulated expression of HO-1 in PDAC cells and increased its nuclear translocation. Inhibition of HO-1 with ZnPP and SnPP sensitized PDAC cells to NPG-induced cytotoxicity (p < 0.05) and increased apoptosis (p < 0.05). Additionally, HO-1 expression was increased in gemcitabine-resistant PDAC cells (p < 0.05), and HO-1 inhibition increased GEM-resistant PDAC sensitivity to NPG (p < 0.05). NPG combined with HO-1 inhibitor inhibited tumor size in an orthotopic model. In parallel, HO-1 inhibition abrogated the influx of macrophages and FoxP3+ cells, while increasing the proportion of CD8+ infiltration in the pancreatic tumors. These effects were mediated primarily by reducing expression of the immunosuppressive cytokine IL-10.

Role of heme oxygenase 1 in cardiac ferroptosis in sickle cell disease

Decreased red blood cell (RBC) half-life in sickle cell disease (SCD) results in increased hemolysis and is associated with stroke and other cardiovascular complications although the exact mechanisms remain unexplored. We hypothesized that increased circulating heme in SCD promotes cardiotoxicity through ferroptosis by upregulating heme oxygenase 1 (Hmox1). Our data demonstrated that sickling Townes mice had higher serum heme, lower serum levels of the heme scavenger protein hemopexin and increased cardiotoxicity and that supplementation with hemopexin decreased cardiotoxicity in sickling mice. We also demonstrated that cardiac expression of Hmox1 was increased in SCD mice; inhibition or induction of Hmox1 decreased or worsened cardiac damage, respectively. We also demonstrated that labile redox-active iron, a product of heme degradation by Hmox1, was increased in SCD. Subsequently, we evaluated if ferroptosis, an iron-dependent non-apoptotic cell death mechanism, resulted from increased Hmox1 and drove cardiotoxicity in SCD. We found an increase in lipid peroxidation and ferroptotic markers in the cardiac tissue of SCD mice, which were corrected by hemopexin and Hmox1 inhibition whereas Hmox1 induction exacerbated lipid peroxidation and cardiac ferroptosis. Finally, inhibitors or inducers of ferroptosis decreased or exacerbated SCD cardiotoxicity respectively. Together, our results identify a novel mechanism for heme-associated cardiac damage in SCD.

Dynamic and Temporal Transcriptomic Analysis Reveals Ferroptosis-Mediated Antileukemia Activity of S-Dimethylarsino-Glutathione: Insights into Novel Therapeutic Strategy

Dynamic and Temporal Transcriptomic Analysis Reveals Ferroptosis-Mediated Antileukemia Activity of S-Dimethylarsino-Glutathione: Insights into Novel Therapeutic Strategy

Kurarinone Attenuates Collagen-Induced Arthritis in Mice by Inhibiting Th1/Th17 Cell Responses and Oxidative Stress.

Kurarinone is a flavanone, extracted from Sophora flavescens Aiton, with multiple biological effects. Here, we determine the therapeutic potential of kurarinone and elucidate the interplay between kurarinone and the autoimmune disease rheumatoid arthritis (RA). Arthritis was recapitulated by induction of bovine collagen II (CII) in DBA/1 mice as a collagen-induced arthritis (CIA) model. After the establishment of the CIA, kurarinone was given orally from day 21 to 42 (100 mg/kg/day) followed by determination of the severity based on a symptom scoring scale and with histopathology. Levels of cytokines, anti-CII antibodies, and the proliferation and lineages of T cells from the draining lymph nodes were measured using ELISA and flow cytometry, respectively. The expressional changes, including STAT1, STAT3, Nrf2, KEAP-1, and heme oxygenase-1 (HO-1) changes in the paw tissues, were evaluated by Western blot assay. Oxidative stress featured with malondiadehyde (MDA) and hydrogen peroxide (H2O2) activities in paw tissues were also evaluated. Results showed that kurarinone treatment reduced arthritis severity of CIA mice, as well as their levels of proinflammatory cytokines, TNF-α, IL-6, IFN-γ, and IL-17A, in the serum and paw tissues. T cell proliferation was also reduced by kurarinone even under the stimulation of CII and anti-CD3 antibody. In addition, kurarinone reduced STAT1 and STAT3 phosphorylation and the proportions of Th1 and Th17 cells in lymph nodes. Moreover, kurarinone suppressed the production of MDA and H2O2. All while promoting enzymatic activities of key antioxidant enzymes, SOD and GSH-Px. In the paw tissues, upregulation of Nrf-2 and HO-1, and downregulation of KEAP-1 were observed. Overall, kurarinone showed an anti-inflammatory effect by inhibiting Th1 and Th17 cell differentiation and an antioxidant effect exerted in part through activating the Nrf-2/KEAP-1 pathway. These beneficial effects in CIA mice contributed to the amelioration of their arthritis, indicating that kurarinone might be an adjunct treatment option for rheumatoid arthritis.

Time dependent impact of copper oxide nanomaterials on the expression of genes associated with oxidative stress, metal binding, inflammation and mucus secretion in single and co-culture intestinal in vitro models

The potential for ingestion of copper oxide nanomaterials (CuO NMs) is increasing due to their increased exploitation. Investigation of changes in gene expression allows toxicity to be detected at an early stage of NM exposure and can enable investigation of the mechanism of toxicity. Here, undifferentiated Caco-2 cells, differentiated Caco-2 cells, Caco-2/HT29-MTX (mucus secreting) and Caco-2/Raji B (M cell model) co-cultures were exposed to CuO NMs and copper sulphate (CuSO4) in order to determine their impacts. Cellular responses were measured in terms of production of reactive oxygen species (ROS), the gene expression of an antioxidant (haem oxygenase 1 (HMOX1)), the pro-inflammatory cytokine (interleukin 8 (IL8)), the metal binding (metallothionein 1A and 2A (MT1A and MT2A)) and the mucus secreting (mucin 2 (MUC2)), as well as HMOX-1 protein level. While CuSO4 induced ROS production in cells, no such effect was observed for CuO NMs. However, these particles did induce an increase in the level of HMOX-1 protein and upregulation of HMOX1, MT2A, IL8 and MUC2 genes in all cell models. In conclusion, the expression of HMOX1, IL8 and MT2A were responsive to CuO NMs at 4 to 12 h post exposure when investigating the toxicity of NMs using intestinal in vitro models. These findings can inform the selection of endpoints, timepoints and models when investigating NM toxicity to the intestine in vitro in the future.

Chrysin Ameliorates Sepsis-Induced Cardiac Dysfunction Through Upregulating Nfr2/Heme Oxygenase 1 Pathway.

The incidence of myocardial dysfunction caused by sepsis is high, and the mortality of patients with sepsis can be significantly increased. During sepsis, oxidative stress and inflammation can lead to severe organ dysfunction. Flavone chrysin is one of the indispensable biological active ingredients for different fruits and vegetables and has antioxidant and anti-inflammatory properties. However, it is not clear whether chrysin is an effective treatment for heart dysfunction caused by sepsis. We found that it had protective effects against the harmful effects caused by LPS, manifested in improved survival, normalized cardiac function, improved partial pathological scores of myocardial tissue, and remission of apoptosis, as well as reduced oxidative stress and inflammation. Mechanism studies have found that chrysin is an important antioxidant protein, a key regulator of heme oxygenase 1 (HO-1). We found that HO-1 levels were increased after LPS intervention, and chrysin further increased HO-1 levels, along with the addition of Nrf2, a regulator of antioxidant proteins. Pretreatment with PD98059, an extracellular signal-regulated kinase-specific inhibitor, blocked chrysin-mediated phosphorylation of Nrf2 and the nuclear translocation of Nrf2. The protective effect of chrysin on sepsis-induced cardiac dysfunction was blocked by ZnPP, which is a HO-1 blocker. Chrysin increased antioxidant activity and reduced markers of oxidative stress (SOD and MDA) and inflammation (MPO and IL-1β), all of which were blocked by ZnPP. This indicates that HO-1 is the upstream molecule regulating the protective effect of chrysin. Thus, by upregulation of HO-1, chrysin protects against LPS-induced cardiac dysfunction and inflammation by inhibiting oxidative stress.

PGE1 triggers Nrf2/HO-1 signal pathway to resist hemin-induced toxicity in mouse cortical neurons.

BackgroundProstaglandin E1 (PGE1) exerts various pharmacological effects such as membrane stabilization, anti-inflammatory functions, vasodilation, and platelet aggregation inhibition. We have previously demonstrated that PGE1 has a beneficial impact on patients suffering from intracerebral hemorrhage (ICH). The related mechanism underlying PGE1’s beneficial effect on ICH treatment needs further exploration.MethodsThe present study elucidates the mechanism of PGE1 on ICH treatment using a neuronal apoptosis model in vitro. The mouse primary cortical neurons were pretreated with different concentrations of PGE1, followed by the treatment with hemin, the main catabolite in whole blood, to mimic the clinical ICH.ResultsComparing with the vehicle-treated group, PGE1 prevented cultured cortical neurons from the accumulation of inhibited intracellular levels of reactive oxygen species (ROS), amelioration of mitochondrial membrane potential, and hemin-induced apoptosis. The reduction of ROS and apoptosis were associated with the up-regulation of Heme oxygenase-1 (HO-1) expression. Knockdown of nuclear transcription factor erythroid 2-related factor (Nrf2) by siRNA attenuated the upregulation of HO-1 as well as the protective effect of PGE1.ConclusionsOur work suggests that the Nrf2/HO-1 molecular pathway may play a crucial role in treating ICH patients with PGE1 and may represent novel molecular targets, resulting in discovering new drugs for ICH treatment.

MicroRNA-100 Mediates Hydrogen Peroxide-Induced Apoptosis of Human Retinal Pigment Epithelium ARPE-19 Cells.

This study investigated the regulatory role of microRNA 100 (miR-100) in hydrogen peroxide (H2O2)-induced apoptosis of human retinal pigment epithelial ARPE-19 cells. H2O2 induced oxidative cell death of cultured ARPE-19 cells was measured by cytotoxicity assay. qRT-PCR was used to quantify cytosolic and extracellular contents of miR-100. Kinase and miR-100 inhibition treatments were applied to determine the regulatory signaling pathways involved in cell death regulation. H2O2 dose-dependently reduced viability of ARPE-19 cells and simultaneously upregulated miR-100 levels in both cytosolic and extracellular compartments. Western blotting detection indicated that H2O2 elicited hyperphosphorylation of PI3K/Akt, ERK1/2, JNK, p38 MAPK, and p65 NF-κB. Further kinase inhibition experiments demonstrated that PI3K, p38 MAPK, and NF-κB activities were involved in oxidative-stress-induced miR-100 upregulation in ARPE-19 cells, while blockade of PI3K, JNK, and NF-κB signaling significantly attenuated the oxidative cell death. Intriguingly, MiR-100 antagomir treatment exerted a cytoprotective effect against the H2O2-induced oxidative cell death through attenuating the oxidation-induced AMPK hyperphosphorylation, restoring cellular mTOR and p62/SQSTM1 levels and upregulating heme oxygenase-1 expression. These findings support that miR-100 at least in part mediates H2O2-induced cell death of ARPE-19 cells and can be regarded as a preventive and therapeutic target for retinal degenerative disease.

Heme Oxygenase-1 in Macrophages Impairs the Perfusion Recovery After Hindlimb Ischemia by Suppressing Autolysosome-Dependent Degradation of NLRP3.

[Figure: see text].

Sevoflurane inhibits ferroptosis: A new mechanism to explain its protective role against lipopolysaccharide-induced acute lung injury

Sevoflurane (Sev) has protective effects in acute lung injury (ALI), but the relevant mechanisms are still not fully understood. The present study aimed to determine whether Sev exerts a protective effect on lipopolysaccharide (LPS)-induced ALI by regulating ferroptosis. In this study, we found that Sev could protect mice from lung injury caused by LPS stimulation, including extenuating lung histological damage, pulmonary edema and pulmonary vascular permeability, and the content of inflammatory factors in Bronchoalveolar lavage fluid (BALF), as well as improving the survival rate of ALI mice, which was in line with the effects of ferroptosis inhibitor ferrostatin-1. Simultaneously, Sev could eliminate the worsening effects of ferroptosis inducer Fe-citrate on LPS-induced ALI to a certain extent. Additionally, the administration of Sev could inhibit ferroptosis caused by LPS, which was manifested by reducing the accumulation of MDA and Fe2+, and increasing the levels of GSH and GPX4 in the lung tissues of ALI mice. It was also observed in BEAS-2B cells that the increased MDA and Fe2+ levels and the decreased GSH and GPX4 levels caused by LPS could be rescued by ferrostatin-1 and Sev. LPS stimulation compensatory up-regulated heme oxygenase-1 (HO-1) expression in mouse lung tissues and BEAS-2B cells, which could be enhanced by Sev. Moreover, HO-1 depletion could offset the inhibitory effect of Sev on LPS-induced ferroptosis and inflammation in BEAS-2B cells. Taken together, Sev inhibited ferroptosis by up-regulating HO-1 expression to reduce LPS-induced ALI, which may provide a possible mechanism for the application of Sev in clinical anesthesia.

Astaxanthin protects against early acute kidney injury in severely burned rats by inactivating the TLR4/MyD88/NF-\u03baB axis and upregulating heme oxygenase-1

Early acute kidney injury (AKI) contributes to severe morbidity and mortality in critically burned patients. Renal inflammation plays a vital role in the progression of early AKI, acting as a therapeutic target. Astaxanthin (ATX) is a strong antioxidant widely distributed in marine organisms that exerts many biological effects in trauma and disease. ATX is also suggested to have anti-inflammatory activity. Hence, we attempted to explore the role of ATX in protecting against early postburn AKI via its anti-inflammatory effects and the related mechanisms. A severely burned model was established for histological and biochemical assessments based on adult male rats. We found that oxidative stress-induced tissue inflammation participated in the development of early AKI after burn injury and that the MyD88-dependent TLR4/NF-κB pathway was activated to regulate renal inflammation. The TLR4 and NF-κB inhibitors TAK242 and PDTC showed similar effects in attenuating burn-induced renal inflammation and early AKI. Upon ATX treatment, the release of inflammatory mediators in the kidneys was downregulated, while the TLR4/MyD88/NF-κB axis was inhibited in a dose-related manner. TAK242 and PDTC could enhance the anti-inflammatory effect of high-dose ATX, whereas lipopolysaccharide (LPS) reversed its action. Furthermore, the expression of heme oxygenase (HO)-1 was upregulated by ATX in a dose-related manner. Collectively, the above data suggest that ATX protects against renal inflammation in a dose-related manner by regulating the TLR4/MyD88/NF-κB axis and HO-1 and ultimately prevents early AKI following severe burns.