Upregulation Of Heme Oxygenase-1 Expression Research Articles

Kaempferol Inhibits P. intermedia Lipopolysaccharide‐Induced Production of Nitric Oxide Through Translational Regulation in Murine Macrophages: Critical Role of Heme Oxygenase‐1‐Mediated ROS Reduction

Nitric oxide (NO) could be a potential target for the development of new therapeutic approaches to the treatment of periodontal disease because this molecule plays a significant role in the tissue destruction observed in periodontitis. In this study, the authors investigate the effect of kaempferol on the production of NO by murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease, and try to determine the underlying mechanisms of action. NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Real-time polymerase chain reaction was performed to quantify inducible NO synthase (iNOS) and heme oxygenase-1 (HO-1) mRNA expression. iNOS and HO-1 protein expression and phosphorylation of c-Jun N-terminal kinase and p38 were characterized via immunoblot analysis. Reactive oxygen species (ROS) production was measured using the redox-sensitive fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate. Kaempferol significantly inhibited NO production and expression of iNOS protein in P. intermedia LPS-stimulated RAW246.7 cells without affecting iNOS mRNA expression. Kaempferol upregulated HO-1 expression in LPS-activated cells. Inhibition of HO-1 activity by tin protoporphyrin IX (SnPP) abolished the suppressive effect of kaempferol on NO production. In addition, kaempferol significantly attenuated P. intermedia LPS-induced increase of intracellular ROS, and SnPP blocked this reduction. Treatment with antioxidants downregulated the production of LPS-induced NO. Kaempferol inhibits NO production and iNOS protein expression in P. intermedia LPS-stimulated RAW264.7 cells at the translational level via HO-1-mediated ROS reduction and could be an efficient modulator of host response in the treatment of periodontal disease.

Impaired heme oxygenase‐1 induction in the gastric antrum induces disruption of the interstitial cells of Cajal network in a rat model of streptozotocin‐induced diabetes

Streptozotocin (STZ) is known to induce type I diabetes and the loss of the interstitial cells of Cajal (ICC). However, the regulation of heme oxygenase-1 (HO-1) expression, which is reported to protect ICC, has not yet been elucidated in this model. The aim of this study was to investigate the alterations of HO-1 expression and clarify the mechanism of ICC loss in the stomach using the rat model of STZ-induced diabetes. Streptozotocin (65mgkg(-1) ) was intraperitoneally administered to 8-week-old female Wistar rats. Cobalt protoporphyrin (CoPP), an HO-1 inducer, was administered subcutaneously once a week after the STZ injection. The expressions of HO-1 and the receptor tyrosine kinase c-Kit (a marker for ICC) proteins were investigated by western blot analysis and immunofluorescence staining. Expression of c-Kit, particularly in the gastric antrum, was significantly decreased at 8weeks, not at 1week, compared to those of the control group. Significantly increased induction of HO-1 expression, especially in the gastric corpus but not in the antrum, was observed in the STZ group at 8weeks after the STZ injection relative to control. CoPP administration significantly up-regulated HO-1 expression in the STZ diabetic group and significantly restored the previously reduced ICC in the gastric antrum. Up-regulation of HO-1 expression in the STZ diabetic model was limited to the gastric corpus and impaired up-regulation of HO-1 expression in the gastric antrum likely induced the disruption of the ICC network.

Hydrogen sulfide upregulates heme oxygenase-1 expression in rats with volume overload-induced heart failure

The present study investigated the role of hydrogen sulfide (H2S), a novel gaseous transmitter, in chronic heart failure (CHF) induced by left-to-right shunt, leading to volume overload. Thirty male Sprague-Dawley rats were randomly divided into four groups: the shunt group, the sham group, the shunt + sodium hydrosulfide (NaHS) group and the sham + NaHS group. CHF was induced in the rats by abdominal aorta-inferior vena cava shunt operation. Rats in the shunt + NaHS and sham + NaHS groups were injected intraperitoneally with NaHS (H2S donor). Haemodynamic parameters were measured 8 weeks after surgery. In addition, left ventricular heme oxygenase (HO)-1 mRNA expression was measured by real-time PCR. Protein expression of HO-1 was evaluated by western blot analysis. Eight weeks after surgery, compared to the sham group, the left ventricular systolic pressure (LVSP) and left ventricular peak rate of contraction and relaxation (LV±dp/dtmax) were significantly reduced; the left ventricular end-diastolic pressure (LVEDP) was significantly increased in the shunt group (all P<0.05). However, NaHS increased LVSP and LV±dp/dtmax (all P<0.05) and decreased LVEDP (P<0.05). Protein expression of HO-1 was significantly decreased in the shunt group compared to that in the sham group (P<0.05). NaHS increased protein expression of HO-1 compared to that in the shunt group (P<0.05). HO-1 mRNA expression was significantly increased in the shunt + NaHS group compared to that in the shunt group (P<0.01). The present study demonstrated that H2S may play a protective role in volume overload-induced CHF by upregulating protein and mRNA expression of HO-1.

Curcumin Ameliorates the Permeability of the Blood–Brain Barrier During Hypoxia by Upregulating Heme Oxygenase-1 Expression in Brain Microvascular Endothelial Cells

Curcumin (Cur) is a major active component of the food flavor turmeric isolated from the powdered dry rhizome of Curcuma longa Linn., which has been used in traditional Chinese medicine to ameliorate intracerebral ischemic damage and reduce brain edema. However, the effects of Cur on the disruption of the blood-brain barrier (BBB) induced by brain ischemia are still unclear. The effects of Cur on the disruption of BBB and changes of tight junction (TJ) proteins induced by oxygen glucose deprivation (OGD) were studied in BBB in vitro. The transendothelial electrical resistance and the flux of horseradish peroxidase in BBB in vitro were measured. The expression and localization of the TJ proteins occludin and zonula occludens-1 (ZO-1) were evaluated by Western blots and immunofluorescence microscopy. The protein levels of heme oxygenase-1 (HO-1) were also analyzed via Western blots. Cur attenuated OGD-induced disruption of paracellular permeability and increased the expression of HO-1 protein in rat brain microvascular endothelial cells (RBMECs). After administration of OGD, the expression of occludin and ZO-1 proteins was restored by Cur, and this effect was blocked by a HO-1 inhibitor, zinc protoporphyrin (ZnPP). Cur protects RBMECs against OGD-induced disruption of TJ and barrier dysfunction via the HO-1 pathway. We propose that Cur is capable of improving the barrier function of BBB under ischemic conditions and this beneficial effect might be reversed by a HO-1 inhibitor, ZnPP.

A novel compound derived from danshensu inhibits apoptosis via upregulation of heme oxygenase-1 expression in SH-SY5Y cells

BackgroundHeme oxygenase-1 (HO-1) has potential anti-apoptotic properties. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2- ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)] was synthesized by joining danshensu and cysteine through an appropriate linker. This study investigated if the cytoprotective properties of DSC involved the induction of HO-1. MethodsWe evaluated the cytoprotective effects of DSC on H2O2-induced cell damage, apoptosis, intracellular and mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm) loss, and apoptosis-related proteins expression and its underlying mechanisms. ResultsDSC concentration-dependently attenuated cell death, lactate dehydrogenase release, intracellular and mitochondrial ROS production, and ΔΨm collapse, modulated apoptosis-related proteins (Bcl-2, Bax, caspase-3, p53, and cleaved PARP) expression, and inhibited phosphorylation of extracellular signal-regulated kinase 1/2 in SH-SY5Y cells induced by H2O2. In addition, DSC concentration-dependently induced HO-1 expression associated with nuclear translocation of nuclear factor-erythroid 2 related factor 2 (Nrf-2), while the effect of DSC was inhibited by a phosphoinositide 3-kinase (PI3K) inhibitor LY294002. Furthermore, the protective effect of DSC on H2O2-induced cell death was abolished by HO-1 inhibitor ZnPP, but was mimicked by carbon monoxide-releasing moiety CORM-3 or HO-1 by-product bilirubin. Finally, DSC inhibited H2O2-induced changes of Bcl-2, Bax, and caspase-3 expression, and all of these effects were reversed by HO-1 silencing. ConclusionsInduction of HO-1 may be, at least in part, responsible for the anti-apoptotic property of DSC, an effect that involved the activation of PI3K/Akt/Nrf-2 axis. General significanceDSC might have the potential for beneficial therapeutic interventions for neurodegenerative diseases.

Anesthetic Isoflurane Posttreatment Attenuates Experimental Lung Injury by Inhibiting Inflammation and Apoptosis

We investigated the effect of 1.4% isoflurane (ISO) on the development of inflammation and apoptosis caused by zymosan (ZY) in mice. We found that ZY-challenged mice exhibited significant body weight loss, markedly high mortality, and significant lung injury characterized by the deterioration of histopathology, histologic scores, and wet-to-dry ratio after ISO treatment. ISO dramatically attenuated ZY-induced lung neutrophil recruitment and inflammation, as evidenced by the reduced levels of total cells, neutrophils, and proinflammatory cytokines (i.e., tumor necrosis factor-α, interleukin- (IL-) 1β, IL-6, and macrophage inflammatory protein-2) in bronchoalveolar lavage fluid and of their mRNA expression in lung tissues. ISO also inhibited ZY-induced expression and activation of nuclear factor-kappaB p65 and inducible nitric oxide synthase in pulmonary tissue. ZY administration also resulted in the upregulation of heme oxygenase-1 expression and activity in the lung, which was further enhanced by ISO treatment. Moreover, ISO markedly prevented ZY-induced pulmonary cell apoptosis in mice, as reflected by the decrease in expression of procaspase-8, procaspase-3, cleaved caspase-8, and cleaved caspase-3, as well as in caspase-3 activity and Bcl-2-associated X/B-cell lymphoma 2 ratio. These results indicate that ISO is a potential therapeutic drug for treating ZY-induced lung injury, and further investigations are warranted.

Acetylshikonin, a Novel AChE Inhibitor, Inhibits Apoptosis via Upregulation of Heme Oxygenase-1 Expression in SH-SY5Y Cells

Acetylcholinesterase inhibitors are prominent alternative in current clinical treatment for AD patients. Therefore, there is a continued need to search for novel AChEIs with good clinical efficacy and less side effects. By using our in-house natural product database and AutoDock Vina as a tool in docking study, we have identified twelve phytochemicals (emodin, aloe-emodin, chrysophanol, and rhein in Rhei Radix Et Rhizoma; xanthotoxin, phellopterin, alloisoimperatorin, and imperatorin in Angelicae dahuricae Radix; shikonin, acetylshikonin, isovalerylshikonin, and β,β-dimethylacrylshikonin in Arnebiae Radix) as candidates of AChEIs that were not previously reported in the literature. In addition to AChEI activity, a series of cell-based experiments were conducted for the investigation of their neuroprotective activities. We found that acetylshikonin and its derivatives prevented apoptotic cell death induced by hydrogen peroxide in human and rat neuronal SH-SY5Y and PC12 cells at 10 μM. We showed that acetylshikonin exhibited the most potent antiapoptosis activity through the inhibition of the generation of reactive oxygen species as well as protection of the loss of mitochondria membrane potential. Furthermore, we identified for the first time that the upregulation of heme oxygenase 1 by acetylshikonin is a key step mediating its antiapoptotic activity from oxidative stress in SH-SY5Y cells.

Knockdown of Nrf2 Inhibits the Angiogenesis of Rat Cardiac Micro-vascular Endothelial Cells under Hypoxic Conditions

Angiogenesis plays an important role in myocardial repair after myocardial infarction (MI). Cardiac micro-vascular endothelial cells (CMECs) are important participants in myocardial angiogenesis processes. Recent studies have revealed that Nuclear factor-erythroid 2-related factor 2 (Nrf2), a master transcription factor of endogenous anti-oxidative defense systems, exerts cardio-protection in the cardiovascular system. However, the role of Nrf2 in the process of myocardial angiogenesis and corresponding mechanisms are not fully understood. Thus, the present study investigated the role of Nrf2 in the angiogenesis of rat CMECs to hypoxia. Trans-well assay, three-dimensional Matrigel assay were used to determine cell migration and vascular tube formation. Real-time RT-PCR, ELISA and Western blot were measured mRNA and protein expression. Here, we report that the mRNA and protein expression of Nrf2 and heme oxygenase-1(HO-1) were temporarily upregulated under hypoxic condition. Furthermore, knock down of Nrf2 significantly suppressed the migration and vascular tube formation of rat CMECs to hypoxia, Nrf2 knockdown also significantly decreased HO-1 and vascular endothelial growth factor (VEGF) expression at 48 h after transfection under hypoxic condition. Finally, transfection of CMECs with the Nrf2 over-expressing lentiviral vector upregulated HO-1 expression with a concomitant increase in cell migration and vascular tube formation induced by hypoxia, and this effect was greatly attenuated in the presence of ZnPP (a HO-1 inhibitor). Taken together, these results suggest that Nrf2 may mediate the angiogenesis of CMECs under hypoxic condition, and HO-1 is involved in regulating the angiogenesis of CMECs through Nrf2. Therefore, Nrf2 is a potent regulator of hypoxia-condition mediated angiogenesis in CMECs, which may provide a therapeutic strategy for myocardial repair after MI.

Carnosic acid protects against ROS/RNS-induced protein damage and upregulates HO-1 expression in RAW264.7 macrophages

The overproduction of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is a deleterious process that can be an important mediator of damage to cell structures including protein, lipid and DNA, and consequently leads to various disease states and senescence. In the present study, the protective effects of carnosic acid (CA) on ROS/RNS-induced protein damages were examined. CA dose-dependently decreased the fragmentation, carbonylation, and nitration of bovine serum albumin (BSA) in AAPH and Hemin/nitrite/H2O2 incubation systems, respectively. Moreover, CA effectively attenuated protein carbonylations in the radical-treated RAW264.7 cells. Furthermore, after pretreatments of RAW264.7 macrophages with CA, the generation of ROS and NO induced by AAPH and H2O2 or LPS were significantly suppressed, and heme oxygenase-1 (HO-1) protein expression was time- and dose-dependently upregulated. Hence, our results indicated that CA might be beneficial for cellular proteins in oxidative stress or inflammation conditions by alleviating ROS/RNS generation and inducing the expression of antioxidant enzyme HO-1.

CHP1002, a novel andrographolide derivative, inhibits pro-inflammatory inducible nitric oxide synthase and cyclooxygenase-2 expressions in RAW264.7 macrophages via up-regulation of heme oxygenase-1 expression

Andrographolides, a type of diterpene lactone, are widely known to have anti-inflammatory and anti-oxidative properties. CHP1002, a synthetic derivative of andrographolide, has similar anti-inflammatory action in mouse ear swelling test and rat paw edema test. In the present study, the mechanism of anti-inflammatory effects of CHP1002 was investigated in RAW264.7 macrophages. CHP1002 potently suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. CHP1002 reduced the production of iNOS-derived nitric oxide (NO) and COX-2-derived prostaglandin E2 (PGE2). CHP1002 induced heme oxygenase-1 (HO-1) expression via activation of extracellular signal-regulated kinase (ERK) and NF-E2 related factor 2 transcription factor (Nrf2). Down-regulation of LPS-induced iNOS and COX-2 expressions was partially reversed by the HO-1 inhibitor zinc protoporphyrin (ZnPP). In addition, CHP1002 significantly attenuated LPS-induced TNF-α, IL-1β and IL-6 production. CHP1002 effectively induced HO-1 and was capable of inhibiting some macrophage-derived pro-inflammatory mediators, which may be closely correlated with its anti-inflammatory action.

NRF2 activation is involved in ozonated human serum upregulation of HO-1 in endothelial cells

During the last decade, it has been shown that the activation of NRF2 and the binding to electrophile-responsive element (EpREs), stimulates the expression of a great number of genes responsible for the synthesis of phase I and phase II proteins, including antioxidants enzymes and heme oxygenase-1 (HO-1). This critical cell response occurs in cardiovascular, degenerative and chronic infective diseases aggravated by a chronic oxidative stress. In our previous reports we have shown that ozonated plasma is able to up-regulate HO-1 expression in endothelial cells. In the present work we investigated a candidate mechanism involved in this process. After treatment with increasing doses of ozonated serum (20, 40 and 80μg/mL O3 per mL of serum), a clear dose dependent activation of NRF2 and the subsequent induction of HO-1 and NAD(P)H quinone oxidoreductase 1(NQO1) was observed. This effect was also present when cells were treated with serum and hydrogen peroxide (H2O2) or serum and 4-hydroxynonenal (4HNE). Moreover, the treatment with ozonated serum was associated with a dose-dependent activation of extracellular-signal-regulated kinases (ERK1/2) and p38 MAP kinases (p38), not directly involved in NRF2 activation.These data, provide a new insight on the mechanism responsible for the induction of HO-1 expression by ozonated serum in the endothelium, and have a practical importance as an expedient approach to the treatment of patients with both effective orthodox drugs and ozonated autohemotherapy, targeted to the restoration of redox homeostasis.

Astaxanthin protects against MPP+-induced oxidative stress in PC12 cells via the HO-1/NOX2 axis

BackgroundAlthough the etiology of PD remains unclear, increasing evidence has shown that oxidative stress plays an important role in its pathogenesis and that of other neurodegenerative disorders. NOX2, a cytochrome subunit of NOX, transports electrons across the plasma membrane to generate ROS, leading to physiological and pathological processes. Heme oxygenase-1 (HO-1) can be rapidly induced by oxidative stress and other noxious stimuli in the brain or other tissues. Astaxanthin (ATX), a carotenoid with antioxidant properties, is 100–1000 times more effective than vitamin E. The present study investigated the neuroprotective effects of ATX on MPP+-induced oxidative stress in PC12 cells.ResultsMPP+ significantly decreased MTT levels in a concentration-dependent manner. Hemin, SnPPIX and ATX didn’t exhibit any cytotoxic effects on PC12 cells. Pretreatment with ATX (5, 10, 20 μM), caused intracellular ROS production in the MPP+ group to decrease by 13.06%, 22.13%, and 27.86%, respectively. MPP+ increased NOX2, NRF2 and HO-1 protein expression compared with control (p < 0.05). Co-treatment with hemin or ATX suppressed NOX2 expression (p < 0.01), and greatly increased NRF2 and HO-1 expression (p < 0.01). MPP+ treatment up-regulated both NOX2 (p < 0.01) and HO-1 (p < 0.01) mRNA levels. Co-treatment with hemin or ATX significantly increased HO-1 mRNA levels (p < 0.01), and decreased NOX2 mRNA levels (p < 0.01). MPP+ increased NOX2 and HO-1 expression with considerable fluorescence extending out from the perinuclear region toward the periphery; this was attenuated by DPI. Co-treatment with hemin or ATX significantly up-regulated HO-1 expression and decreased NOX2 expression with considerable fluorescence intensity (stronger than the control and MPP+ groups).ConclusionsATX suppresses MPP+-induced oxidative stress in PC12 cells via the HO-1/NOX2 axis. ATX should be strongly considered as a potential neuroprotectant and adjuvant therapy for patients with Parkinson’s disease.

Upregulation of heme oxygenase-1 expression for protecting against myocardial ischemia and reperfusion injury

Myocardial ischemia and reperfusion (I/R) injury is frequently encountered in clinical practice because of the wide utilization of percutaneous coronary intervention in acute myocardial infarction caused by coronary thrombosis. Heme oxygenase-1 (HO-1) or heat shock protein 32, the rate-limiting enzyme responsible for the breakdown of heme into free ferrous iron, carbon monoxide, and bilirubin, confers protection against cellular stress [1]. Several studies indicated that the upregulation of HO-1 expression could provide a protective effect on myocardial I/R injury. Thus, HO-1 is regarded as an important therapeutic target for protecting against myocardial I/R injury [2]. Searching and exploiting the inducers of HO-1, understanding the signal pathways that induce HO-1, and determining themolecularmechanism behind the beneficial effects of HO-1 may facilitate the development of novel drugs and methods for protecting against myocardial I/R injury. Numerous clinical and experimental pharmacologic compounds, such as heme, anoxia, hyperxia, heavy metals, inflammatory factors, statins, proton pump inhibitors, and sevoflurane, reportedly induce HO1 expression [3]. Several active ingredients of traditional Chinese medicinal herbs are utilized to reduce myocardial I/R injury in clinical practice, some of their effects exert probably through inducing HO-1 expression. Understanding the mechanism behind their protective effects is essential to promote their clinical application.We reported that hydroxysafflor yellow A, a chemical compound isolated from Carthamus tinctorius L, could upregulate the expression of HO-1 and confer protection against anoxia/reoxygenation-induced apoptosis in H9c2 cardiomyocytes [4]. The active ingredients of traditional Chinese medicinal herbs such as 2-methoxycinnamaldehyde, tetramethylpyrazine, and higenamine were also proved that could induce HO-1 expression and attenuate myocardial I/R injury in rats [5–7]. The mitogen-activated protein kinase-activated signal pathway and the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB, Akt) signal pathway, and signaling molecules such as protein kinase C and tyrosine kinase are involved in HO-1 regulation [8]. The janus protein tyrosine kinase/signal transducer and activator of transcription signal pathway certified the pathway via which regulation of HO-1 expression by interleukin-6 in rat hepatocytes [9]. Our recent study has shown that hydroxysafflor yellow A could upregulate the expression and activity of HO-1 through the PI3K/Akt/nuclear factor erythroid-2-related factor 2 pathway in H9c2 cardiomyocytes [4]. The mechanism by which several active ingredients of traditional Chinese medicinal herbs such as 2-methoxycinnamaldehyde, tetramethylpyrazine, and higenamine induce HO-1 expression to attenuate myocardial I/R injury through the signal transduction pathway should be further studied. The protective function of HO-1 against myocardial I/R injury was demonstrated by the utilization of pharmacological methods and genetic approaches in experiment research and clinical practice [10]. Searching and exploiting new inducers of HO-1, activating the signal pathways that induce HO-1, and using gene therapy are the strategies that we can utilize to protect against myocardial I/R injury through this important therapeutic target. Monomers of traditional Chinese medicinal herbs have multiple effects and multiple mechanism of actionwith few side effects. Exploiting the inducers of HO-1 from traditional Chinese medicinal herbs and studying its mechanism of action will provide more options for protecting against myocardial I/R injury. The authors of this manuscript have also certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

English

To investigate heme oxygenase-1(HO-1) expression induced by sevoflurane in lipopolysaccharide (LPS)-induced acute lung injury (ALI). Forty-eight rats were randomly designated into six groups to receive normal saline (NS), ZnPPIX(a specific HO-1 inhibitor), or sevoflurane: A (control, NS&nbsp;only),&nbsp;B (ZnPPIX&nbsp;only), C (sevoflurane only), D (LPS + 1.0 minimum alveolar concentration (MAC) sevoflurane), E (ZnPPIX + LPS +1.0 MAC sevoflurane) and F (LPS only).&nbsp;We evaluated the histopathologic changes, W/D ratio, and the activity of SOD, MDA, MPO, and HO-1 using the traditional methods. The mRNA and protein expression of ICAM-1, CINC, and HO-1 was detected by&nbsp;RT-PCR and western blotting. No significant difference was observed between group A, B, and C. LPS treatment (group D, E and F) could&nbsp;elicit serious&nbsp;lung injury in histopathology. The wet/dry ratio, MDA, MPO, and HO-1 activity, the mRNA and protein expression of ICAM-1 and CINC were significantly increased after LPS treatment (p &lt; 0.05). Sevoflurane post-conditioning (Group F) could further promote HO-1 up-regulated expression and effectively protect ALI with decreasing pathomorphological scores, MPO activity, W/D, and the mRNA and protein expression of ICAM-1, and CINC. Sevoflurane post-conditioning may be an effective inducer to up-regulate HO-1 expression to alleviate ALI. &nbsp; Key words:&nbsp;Sevoflurane,&nbsp;acute lung injury, HO-1.

Effect of c-AMP-protein kinase A on up-regulation of heme oxygenase-1 expresion during lipopolysac-charide-induced acute lung injury in rats

Objective To evaluate the role of c-AMP-protein kinase A (cAMP-PKA) on the up-regulation of heme oxygenase-1 (HO-1) expression during lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats.Methods Forty-eight healthy male Sprague-Dawley rats,weighing 180-220 g,aged 2.5-3.0 months,were randomly divided into 4 groups (n =12 each)∶ normal control group (group C),ALI group (group ALI),H89 +ALI group (group H + ALI) and H89 group (group H).In group C,normal saline (solvent for LPS) 0.5 ml was injected via the femoral vein and normal saline (solvent for H89) 0.5 ml was injected subcutaneously 2 h later.In group ALI,10 mg/kg LPS 0.5 ml was injected via the femoral vein and normal saline 0.5 ml was injected subcutaneously 2 h later.In group H +ALI,10 mg/kg LPS 0.5 ml was injected via the femoral vein and 5 mg/kg H89 0.5ml was injected subcutaneously 2 h later.In group H,normal saline 0.5 ml was injected via the femoral vein and 5 mg/kg H89 0.5 ml was injected subcutaneously 2 h later.The rats were then sacrificed at 6 h after iv injection of LPS and the lungs were removed for microscopic examination and lung water content.The pathological changes of the lung were scored.The expression of HO-1 and PKA (by Western blot) and HO-1 mRNA (by RT-PCR) was detected.Results Compared with group C,the pathological score and lung water content were significantly increased,and the expression of HO-1,PKA and HO-1 mRNA was up-regulated in groups ALI and H +ALI (P ＜0.05),and no significant change was found in the parameters mentioned above in group H (P ＞ 0.05).The pathological score and lung water content were significantly higher,and the expression of HO-1,AP-1 and HO-1 mRNA was significantly lower in group H + ALI than in group ALI (P ＜ 0.05).Conclusion Activation of signaling pathway c-AMP-PKA is involved in the up-regulation of HO-1 expression during LPS-induced ALI in rats. Key words: Cyclic AMP-dependent protein kinases ; Heme oxygenase-1 ; Endotoxemia ; Respiratory distress syndrome, adult

1,2,3,4,6-penta-O-galloyl-β-D-glucose protects PC12 Cells from MPP+-mediated cell death by inducing heme oxygenase-1 in an ERK- and Akt-dependent manner

This study examined the ability of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (β-PGG) to induce the expression of heme oxygenase-1 (HO-1) in the PC12 cells and its regulation in the PC12 cells. One week before treatment with the drug, nerve growth factor (NGF) was added to the cultures at a final concentration of 50 ng/mL to induce neuronal differentiation. After drug treatment, HO-1 gene transcription was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Expression of HO-1 and NF-E2-related factor2 (Nrf2) and activation of extracellular signal-regulated kinase (ERK) and Akt were detected by Western blotting. The viability of the PC12 cells treated with different medicines was examined by MTT assay. The oxidative stress in the PC12 cells was evaluated qualitatively and quantitatively by DCFH-DA. The results showed that β-PGG up-regulated HO-1 expression and this increased expression provided neuroprotection against MPP(+)-induced oxidative injury. Moreover, β-PGG induced Nrf2 nuclear translocation, which was found to be upstream of β-PGG-induced HO-1 expression, and the activation of ERK and Akt, a pathway that is involved in β-PGG-induced Nrf2 nuclear translocation, HO-1 expression and neuroprotection. In conclusion, β-PGG up-regulates HO-1 expression by stimulating Nrf2 nuclear translocation in an ERK- and Akt-dependent manner, and HO-1 expression by β-PGG may provide the PC12 cells with an acquired antioxidant defense capacity to survive the oxidative stress.

Role of activator protein-1 in up-regulation of heme oxygenase-1 expression during lipopolysaccharide-induced acute lung injury in rats

Objective To evaluate the role of activator protein-1 (AP-1) in the up-regulation of heme oxygenase-1 (HO-1) expression during lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats.Methods Forty-eight healthy male Sprague-Dawley rats,weighing 200-220 g,aged 2.5-3.0 months,were randomly divided into 4 groups (n=12 each): normal control group (group C),ALI group,curcumin + ALI group (group Cur+ ALI),and curcumin group (group Cur).In groups C and ALI,normal saline 0.5 ml and LPS 10 mg/kg (0.5 ml) were injected intravenously,respectively,30 min after 0.1％ dimethyl sulfoxide (the vehicle for curcumin) 0.5 ml was injected intraperitoneally.In groups Cur+ ALl and Cur,curcumin 20 mg/kg (0.5 ml) was injected intraperitoneally,and 30 min later LPS 10 mg/kg and normal saline 0.5 ml were injected,respectively.The rats were then sacrificed at 6 h after injection of LPS.The lungs were removed for microscopic examination.The pathological changes of the lung were scored.The malondialdehyde (MDA) content,superoxide dismutase (SOD)activity and expression of HO-1,AP-1 and HO-1 mRNA in lung tissues were determined.Results Compared with group C,the pathological score and MDA content were significantly increased,the SOD activity was significantly decreased,and the expression of HO-1,AP-1 and HO-1 mRNA was up-regulated in groups ALl and Cur +AL(l) (P ＜ 0.05),and no significant change was found in the parameters mentioned above in group Cur (P ＞ 0.05).The pathological score and MDA content were significantly higher,and the SOD activity and expression of HO-1,AP-1 and HO-1 mRNA were significantly lower in group Cur + ALl than in group ALI(P ＜ 0.05).Conclusion Transcription factor AP-1 activation is involved in the up-regulation of HO-1 expression during LPS-induced ALI in rats. Key words: Activator protein-1; Endotoxemia; Heme oxygenase-1; Respiratory distress syndrome,adult

Effects of hydrogen-rich medium on lipopolysaccharide-induced release of inflammatory cytokines from RAW264.7 macrophages

Objective To investigate the effects of hydrogen-rich medium on lipopolysaccharide (LPS)-induced release of inflammatory cytokines from murine macrophage RAW264.7 cells.Methods The RAW264.7cells were cultured in DMEM culture medium containing 10％ fetal bovine serum.The cells were seeded in 6-well plates (3 ml/hole) with a density of 2 × 106/ml and randomly divided into 4 groups (n =24 each):control group (group A),hydrogen-rich medium group (group B),LPS group (group C) and LPS + hydrogen-rich medium group (group D).Group A received no treatment.LPS 1 μg/ml was added to the medium in groups C and D,while the cells were incubated with 0.6 mmol/L hydrogen-rich medium simultaneously in groups B and D.Six wells in each group were chosen at 6,12.24 and 48 h of incubation,and the supernatant was collected to detect the concentrations of TNF-α,IL-1β and IL-10.Six wells in each group were chosen at 6 and 12 h of incubation for determination of heme oxygenase-1 (HO-1) expression in the cells by Western blot.Results Compared with group A,the concentrations of TNF-α,IL-1β and IL-10 in the supernatant were significantly increased,and the expression of HO-1 was up-regulated in group C (P ＜ 0.05).Compared with group C,the concentrations of TNF-α and IL-1β in the supernatant were significantly decreased,the concentration of IL-10 in the supernatant was significantly increased,and the expression of HO-1 was up-regulated in group D (P ＜ 0.05).Conclusion Hydrogen-rich medium can inhibit the release of pro-inflammatory cytokines and promote the release of anti-inflammatory cytokines from RAW264.7 cells via up-regulating HO-1 expression. Key words: Hydrogen; Endotoxemia; Macrophages; Inflammation

Insulin-Like Growth Factor-1 Inhibits 6-Hydroxydopamine-Mediated Endoplasmic Reticulum Stress-Induced Apoptosis via Regulation of Heme Oxygenase-1 and Nrf2 Expression in PC12 Cells

ABSTRACTEndoplasmic reticulum (ER) stress and oxidative stress appear to play a critical role in the progression of Parkinson's disease (PD). Insulin-like growth factor (IGF)-1, a 70-amino acid polypeptide trophic factor, acts as a potent neurotrophic, neurogenic, and neuroprotective/anti-apoptotic factor. In this study, we investigated the protective mechanisms of IGF-1 in rat pheochromocytoma PC12 cells exposed to the PD-related neurotoxin 6-hydroxydopamine (6-OHDA). The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) coordinates expression of genes required for free radical scavenging, detoxification of xenobiotics, and maintenance of redox potential. Exposure of cells to 6-OHDA resulted in an increase in ER-stress-induced apoptotic cell death, which was significantly reduced by treatment of cells with IGF-1. IGF-1 treatment significantly increased BiP and C/EBP homologous protein expression in 6-OHDA-treated cultures. IGF-1 protected cells from 6-OHDA-induced insult by inhibiting intracellular reactive oxygen species generation. Compared with vehicle-treated controls, the expression of Nrf2 and heme oxygenase-1 (HO-1) was increased in 6-OHDA-treated cells. IGF-1 significantly up-regulated HO-1 in cells exposed to 6-OHDA. These results suggest that IGF-1 augment cellular anti-oxidant defense mechanism, at least in part, through the up-regulation of HO-1 expression.

Role of p38MAPK signaling pathway in up-regulation of heme oxygenase-1 expression in lung tissues in rats with acute lung injury induced by endotoxic shock

Objective To evaluate the role of p38MAPK signaling pathway in the up-regulation of heme oxygenase-1 (HO-1) expression in the lung tissue in rats with acute lung injury (AL1) induced by endotoxic shock.Methods Forty-eight male SD rats,aged 8 weeks,weighing 180-200 g,were randomly divided into 4 groups ( n =12 each):control group ( group C ) ; endotoxic shock group ( group LS );endotoxic shock +SB203580 (a specific p38MAPK inhibitor) group (group LSS) and SB203580 group (group SB).Normal saline 0.5ml was injected via the femoral vein in groups C and SB,while LPS 10 mg/kg (in 0.5 ml normal saline) was injected via the femoral vein in groups LS and LSS.When MAP was decreased to 75％ of baseline value,10％ dimethyl sulfoxide (DMSO) 0.1 ml was infused via the femoral vein in groups C and LS,while SB203580 5 mol/kg (in 10％ DMSO 0.1 ml) was infused via the femoral vein at a rate of 0.01 ml/min in groups LSS and SB.Arterial blood samples were obtained at 6 h after LPS or normal saline was given for blood gas analysis and oxygenation index (PaO2/FiO2) was calculated.Then the rats were sacrificed and the lungs were removed for microscopic examination.The pathological changes of the lung were scored.The lung water content was calculated.The MDA content,SOD activity,and expression of HO-1 mRNA and protein,p38MAPK protein and phospharylated p38MAPK (p-p38MAPK) protein were determined.Results Compared with group C,the oxygenation index and SOD activity were significantly decreased,the pathological score,lung water content and MDA content were significantly increased,and the expression of HO-1 mRNA and protein and p-p38MAPK protein was significantly up-regulated ( P＜0.05),while no significant change was found in p38MAPK protein expression in groups LS and LSS,and no significant change was found in the indexes mentioned above in group SB (P＞0.05).Compared with group LS,the oxygenation index and SOD activity were significantly increased,the pathological score,lung water content and MDA content were significantly decreased,the expression of HO-1 mRNA and protein was significantly up-regulated,and p-p38MAPK protein expression was down-regulated ( P＜0.05),and no significant change was found in p38MAPK protein expression in group LSS ( P＞0.05).Conclusion The inhibition of p38MAPK signaling pathway can lead to the up-regulation of HO-1 expression in lung tissues in rats with ALI induced by endotoxic shock. Key words: p38 Mitogen-activated protein kinases; Hemne oxygenase-1; Lung; Shock,septic; Respiratory distress syndrome,adult