Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions thro...Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions through methanotrophs can provide crucial information for understanding the harsh C-H activation of methane.Soluble methane monooxygenase(sMMO)belongs to the bacterial multi-component monooxygenase superfamily and requires hydroxylase(MMOH),regulatory(MMOB),and reductase(MMOR)components.Recent structural and biophysical studies have demonstrated that these components accelerate and retard methane hydroxylation in MMOH through protein-protein interactions.Complex structures of sMMO,including MMOH-MMOB and MMOH-MMOD,illustrate how these regulatory and inhibitory components orchestrate the di-iron active sites located within the four-helix bundles of MMOH,specifically at the docking surface known as the canyon region.In addition,recent biophysical studies have demonstrated the role of MmoR,aσ54-dependent transcriptional regulator,in regulating sMMO expression.This perspective article introduces remarkable discoveries in recent reports on sMMO components that are crucial for understanding sMMO expression and activities.Our findings provide insight into how sMMO components interact with MMOH to control methane hydroxylation,shedding light on the mechanisms governing sMMO expression and the interactions between activating enzymes and promoters.展开更多
AIM： To study the effect of bilirubin on the oxidative liver status and the activity and expression of heine oxygenase-1 （HO-1） in rat liver injury induced by prehepatic portal hypertension. METHODS： Wistar male r...AIM： To study the effect of bilirubin on the oxidative liver status and the activity and expression of heine oxygenase-1 （HO-1） in rat liver injury induced by prehepatic portal hypertension. METHODS： Wistar male rats, weighing 200-250 g, were divided at random into two groups： one group with prehepatic portal hypertension （PH） induced by regulated prehepatic portal vein ligation （PPVL） and the other group corresponded to sham operated rats. Portal pressure, oxidative stress parameters, antioxidant enzymes, HO-1 activity and expression and hepatic sinusoidal vasodilatation were measured. RESULTS： In PPVL rats oxidative stress was evidenced by a marked increase in thiobarbituric acid reactive substances （TBARS） content and a decrease in reduced glutathione （GSH） levels. The activities of liver antioxidant enzymes, superoxide dismutase （SOD）, catalase （CAT） and glutathione peroxidase （GSH-Px） were also diminished while activity and expression of HO-1 were enhanced. Administration of bilirubin （5μmol/kg body weight） 24 h before the end of the experiment entirely prevented all these effects. Pretreatment with Sn-protoporphyrin IX （Sn-PPIX） （100 μg/kg body weight, i.p.）, a potent inhibitor of HO, completely abolished the oxidative stress and provoked a slight decrease in liver GSH levels as well as an increase in lipid peroxidation. Besides, carbon monoxide, another heme catabolic product, induced a significant increase in sinusoidal hepatic areas in PPVL group. Pretreatment of PPVL rats with Sn-PPIX totally prevented this effect CONCLUSION： These results suggest a beneficial role of HO-1 overexpression in prehepatic portal hypertensive rats.展开更多
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,ca...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 stressresponse 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,itsroles 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.展开更多
AIM： To investigate the effects of heme oxygenase-1 （HO-1） against oxidant-induced injury caused by bile duct ligation （BDL）.METHODS： Either cobalt protoporphyrin （CoPP）, a HO-1 inducer, or saline were injecte...AIM： To investigate the effects of heme oxygenase-1 （HO-1） against oxidant-induced injury caused by bile duct ligation （BDL）.METHODS： Either cobalt protoporphyrin （CoPP）, a HO-1 inducer, or saline were injected intraperitoneally in male SD-rats. Three days later, BDL or sham-operations were performed. Rats were sacrificed 3 wk after BDL and livers were harvested for histology. Fibrosis was evaluated by sirius red staining and image analysis. Alpha-smooth muscular actin, which indicates activation of stellate cells, was detected by immunohistochemical staining, and q/tokine and collagen- Iα （Col- I α） mRNA expression was detected using RNase protection assays.RESULTS： Serum alanine transaminase increased 8-fold above normal levels one day after BDL. Surprisingly, enzyme release was not reduced in rats receiving CoPP. Liver fibrosis was evaluated 3 wk after BDL and the sirius red-positive area was found to be increased to about 7.8%. However, in CoPP pretreated rats sirius redpositive areas were increased to about 11.7% after BDL. Collagen-1 α and TGF-β mRNA increased significantly by BDL. Again, this effect was increased by HO-1 overexpression.CONCLUSION： Hepatic fibrosis due to BDL is not reduced by the HO-1 inducer CoPP. In contrast, HO-1 overexpression increases liver injury in rats under conditions of experimental chronic cholestasis.展开更多
Many physiological effects of natural antioxidants, their extracts or their major active components, have been reported in recent decades. Most of these compounds are characterized by a phenolic structure, similar to ...Many physiological effects of natural antioxidants, their extracts or their major active components, have been reported in recent decades. Most of these compounds are characterized by a phenolic structure, similar to that of o-tocopherol, and present antioxidant properties that have been demonstrated both in vitro and in vivo. Polyphenors may increase the capacity of endogenous antioxidant defences and modulate the cellular redox state. Changes in the cellular redox state may have wide-ranging consequences for cellular growth and differentiation. The majority of in vitro and in vivo studies conducted so far have attributed the protective effect of bioactive polyphenols to their chemical reactivity toward free radicals and their capacity to prevent the oxidation of important intracellular components. However, in recent years a possible novel aspect inthe mode of action of these compounds has been suggested; that is, the ultimate stimulation of the heme oxygenase-1 （HO-1） pathway is likely to account for the established and powerful antioxidant/anti-inflammatory properties of these polyphenols. The products of the HO-catalyzed reaction, particularly carbon mon- oxide （CO） and biliverdin/bilirubin have been shown to exert protective effects in several organs against oxidative and other noxious stimuli. In this context, it is interesting to note that induction of HO-1 expression by means of natural compounds contributes to protection against liver damage in various experimental models. The focus of this review is on the significance of targeted induction of HO-1 as a potential therapeutic strategy to protect the liver against various stressors in several pathological conditions.展开更多
Background Myocardial infarction （MI） has likely contributed to the increased prevalence of heart failure （HF）. As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi...Background Myocardial infarction （MI） has likely contributed to the increased prevalence of heart failure （HF）. As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi and damage to the intestinal barrier. The induction of heme oxygenase-1 （HO-1） could prevent, or lessen the effects of stress and inflammation. Thus, the effect and mechanism thereof of HO-1 on the intestines of rats with HF was investigated. Methods Male Wistar rats with heart failure through ligation of the left coronary artery were identified with an left ventricular ejection fraction of 〈 45% through echocardiography and then divided into various experimental groups based on the type of peritoneal injection they received [MI： saline; MI ＋ Cobalt protoporphyrin （CoPP）： CoPP solution; and MI ＋ Tin mesoporphyrin IX dichloride （SnMP）： SnMP solution]. The control group was comprised of rats without coronary ligation. Echocardiogra- phy was performed before ligation for a baseline and eight weeks after ligation in order to evaluate the cardiac function of the rats. The bac- terial translocation （BT） incidence, mesenteric microcirculation, amount of endotoxins in the vein serum, ileum levels of HO- 1, carbon oxide （CO）, nitric oxide （NO）, intedeuldn （IL）-10, turnour necrosis factor-et （TNF-ct）, and the ileum morphology were determined eight weeks after the operation. Results The rats receiving MI ＋ CoPP injections exhibited a recovery in cardiac function, an amelioration of mesenteric microcirculation and change in morphology, a lower BT incidence, a reduction in serum and ileac NO and TNF-ct levels, and an elevation in ileac HO-1, CO, and interleukin-10 （[L-10） levels compared to the MI group （P 〈 0.05）. The rats that received the MI ＋ SnMP injections exhibited results inverse to the MI （P 〈 0.05） group. Conclusions HO-1 exerted a protective effect on the intestines of rats with HF by inhibiting the inflammation and amelioration of microcirculation through the CO pathway. This protective effect could be independent from the recovery of cardiac function.展开更多
Heme oxygenase-1(HO-1) system catalyzes heme to biologically active products:carbon monoxide,biliverdin/bilirubin and free iron.It is involved in maintaining cellular homeostasis and many physiological and pathophysio...Heme oxygenase-1(HO-1) system catalyzes heme to biologically active products:carbon monoxide,biliverdin/bilirubin and free iron.It is involved in maintaining cellular homeostasis and many physiological and pathophysiological processes.A growing body of evidence indicates that HO-1 activation may play an important protective role in acute and chronic inflammation of gastrointestinal tract.This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal inflammation studied to date.The ability to upregulate HO-1 by pharmacological means or using gene therapy may offer therapeutic strategies for gastrointestinal inflammation in the future.展开更多
AIM: To examine the potency of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) as a hepatic heme oxygen-ase-1(HO-1) inducer and its regulation in HepG2 cells. METHODS: Expression of HO-1 and NF-E2-related factor 2 (Nrf2)...AIM: To examine the potency of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) as a hepatic heme oxygen-ase-1(HO-1) inducer and its regulation in HepG2 cells. METHODS: Expression of HO-1 and NF-E2-related factor 2 (Nrf2) and activation of mitogen-activated protein (MAP) kinases were analyzed by Western blot, immuno-fluorescence assay, and flow cytometry. Transfections of HO-1 gene, small interfering RNAs for HO-1 and Nrf2, and dominant-negative gene for MAP/extracellular signal-regulated kinase (ERK) were carried out to dissect the signaling pathways leading to HO-1 expression in HepG 2 cells. RESULTS: PGG up-regulated HO-1 expression and this expression conferred cytoprotection against oxidative injury induced by t-butyl hydroperoxide. Moreover, PGG induced Nrf2 nuclear translocation, which was found to be an upstream step of PGG-induced HO-1 expression, and ERK activation, of which pathway was involved in PGG-induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection. CONCLUSION: PGG up-regulates HO-1 expression by stimulating Nrf2 nuclear translocation in an ERK-depen-dent manner, and HO-1 expression by PGG may serve as one of the important mechanisms for its hepatoprotective effects.展开更多
AIM： To investigate the molecular mechanism and functional consequences of heme oxygenase-1 （HO-1） activation by lansoprazole in endothelial cells and macrophages. METHODS： Expression of HO-1 mRNA was analyzed by ...AIM： To investigate the molecular mechanism and functional consequences of heme oxygenase-1 （HO-1） activation by lansoprazole in endothelial cells and macrophages. METHODS： Expression of HO-1 mRNA was analyzed by Northern blotting. Western blotting was used to determine the HO-1 and ferritin protein levels. NADPH-dependent reactive oxygen species （ROS） formation was measured with lucigenin-enhanced chemiluminescence. HO-1 promoter activity in mouse fibroblasts, stably transfected with a 15-kb HO-1 gene that drives expression of the reporter gene luciferase, was assessed usingin vivo bioluminescence imaging. RESULTS： Lansoprazole levels in endothelial cells increased HO-1 mRNA and HO-1 protein levels in macrophages. In addition, lansoprazole-induced ferritin protein levels in both cell systems. Moreover, induction of the antioxidant proteins HO-1 and ferritin by lansoprazole was followed by a decrease in NADPH- mediated ROS formation. The radical scavenging properties of lansoprazole were diminished in the presence of the HO inhibitor, chromium mesoporphyrin IX. Induction of HO-1 gene expression by lansoprazole was not related to oxidative stress or to the activation of the mitogen-activated protein kinase pathway. However, the phosphatidylinositol 3-kinase inhibitor LY294002 showed a concentration-dependent inhibition of HO-1 mRNA and promoter activity.CONCLUSION： Activation of HO-1 and ferritin may account for the gastric protection of lansoprazole and is dependent on a pathway blocked by LY294002.展开更多
AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per ...AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per group)into five groups:I/R group(4 h of liver cold ischemia followed by 6 h of reperfusion);heme oxygenase-1(HO-1)small interfering RNA(siRNA)group(injection of siRNA via donor portal vein 48 h prior to harvest);diazoxide(DZ) group(injection of DZ via donor portal vein 10 min prior to harvest);HO-1 siRNA+DZ group;and siRNA control group.Blood and liver samples were collected at 6 h after reperfusion.The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting,and tissue morphology was examined by light and transmission electron microscopy.Serum transaminases level and cytokines concentration were also measured.RESULTS:We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA+DZ group when compared with I/R group,while the increases were prominent in the DZ group.Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA+DZ groups compared with DZ group.Serum alanine aminotransferase,aspartate transaminase,tumor necrosis factor-αand interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA+DZ groups,and decreased in the DZ group.CONCLUSION:The protective effect of DZ may be induced by upregulation of HO-1.By inhibiting expression of HO-1,this protection pretreated with DZ was abolished.展开更多
AIM:To investigate the effects of antithrombin Ⅲ(AT Ⅲ) injection via the portal vein in acute liver failure.METHODS:Thirty rats were intraperitoneally challenged with lipopolysaccharide(LPS) and D-galactosamine(GalN...AIM:To investigate the effects of antithrombin Ⅲ(AT Ⅲ) injection via the portal vein in acute liver failure.METHODS:Thirty rats were intraperitoneally challenged with lipopolysaccharide(LPS) and D-galactosamine(GalN) and divided into three groups:a control group;a group injected with AT Ⅲ via the tail vein;and a group injected with AT Ⅲ via the portal vein.AT Ⅲ(50 U/kg body weight) was administrated 1 h after challenge with LPS and GalN.Serum levels of inflammatory cytokines and fibrin degradation products,hepatic fibrin deposition,and hepatic mRNA expression of hypoxiarelated genes were analyzed.RESULTS:Serum levels of alanine aminotransferase,tumor necrosis factor-α and interleukin-6 decreased significantly following portal vein AT Ⅲ injection compared with tail vein injection,and control rats.Portal vein AT Ⅲ injection reduced liver cell destruction and decreased hepatic fibrin deposition.This treatment also significantly reduced hepatic mRNA expression of lactate dehydrogenase and heme oxygenase-1.CONCLUSION:A clinically acceptable dose of AT Ⅲ injection into the portal vein suppressed liver damage,probably through its enhanced anticoagulant and antiinflammatory activities.展开更多
AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN...AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN + pentobarbital sodium(PEN);2:LEAN + ISO;3:FAT + PEN;4:FAT + ISO.The animals were mechanically ventilated for 6 h.In vitro analyses of liver tissue included determination of HO-1 mRNA and protein expression as well as measurement of HO enzyme activity and immunohistochemical analyses.RESULTS:Compared to PEN treatment,ISO administration profoundly induced hepatic HO-1 mRNA and protein expression and significantly increased HO enzyme activity in lean Zucker rats.In contrast,no difference in HO-1 gene expression was observed after ISO or PEN anesthesia in obese Zucker rats.CONCLUSION:The present study demonstrates that ISO is an inducer of hepatic HO-1 gene expression in non-steatotic organs but failed to upregulate HO-1 in steatotic livers.展开更多
It aims to analyze the impact heme oxygenase -1 （heme oxygenase 1, HO-1） on regulating factors of human hepatoma cell HepG2＇s cell cycle, through constructing recombinant vector of pcDNA3.1 containing wild-type and...It aims to analyze the impact heme oxygenase -1 （heme oxygenase 1, HO-1） on regulating factors of human hepatoma cell HepG2＇s cell cycle, through constructing recombinant vector of pcDNA3.1 containing wild-type and mutant HO-1 gene （＋）-wtHO-1 and pcDNA3.1 （＋）-mHO-1G143H. By using the method of liposome-mediated, the recombinant vector was transfected hepatoma cell line HepG2. And the transfected one with empty vector was treated as a control group. By the selection of G418, stable expression of wild-type and mutant HO-1 in HepG2 liver cancer cell lines were established. Use the blot of semi-quantitative RT-PCR and Western to test transfected cell lines expressing levels of riO-1 mRNA and protein. As HO-1 expression in stably transfected cell lines altered, we use Western blot to test transfected cell lines P21, P27 protein expression levels. As result shows, we got 1 HO-over-expression of wild-type and mutant in HepG2 cells; wild- type and mutant＇s over expression of HO-1 can induce the expression of tumor suppressor genes p21 and p27.we got the conclusion that HO-l＇s over-expression of tumor suppressor genes p21 and p27 is unrelated to the expression of heme decomposition products. HO-1 may regulate the expression of p21 and p27 through other mechanisms.展开更多
Objective To prepare rat heme oxygenase 1 (HO 1) mutants and to determine the activity and inhibition of this mutated enzyme Methods pcDNA3HO1 containing truncated native rat HO 1 cDNA and pcDNA3HO1Δ25 carr...Objective To prepare rat heme oxygenase 1 (HO 1) mutants and to determine the activity and inhibition of this mutated enzyme Methods pcDNA3HO1 containing truncated native rat HO 1 cDNA and pcDNA3HO1Δ25 carrying mutated rat HO 1 cDNA (His25Ala) were constructed, respectively COS 1 cells transfected with pcDNA3HO1 and pcDNA3HO1Δ25 were collected and their activities were analyzed Results Native rat HO 1 was highly expressed in transfected cells and its activity was 13?688-15?600?U/mg protein per hour However, the enzyme activity of mutated HO 1 declined and the value was 1948-2160?U/mg protein per hour When an equal amount of mutant was added to the enzyme reaction system, the level of bilirubin decreased by 42% Conclusion The His25Ala mutant reduced the formation of bilirubin, suggesting that the mutant could competely bind the heme with native enzyme展开更多
文摘Methane(CH_(4))has a higher heat capacity(104.9 kcal/mol)than carbon dioxide(CO_(2)),and this has inspired research aimed at reducing methane levels to retard global warming.Hydroxylation under ambient conditions through methanotrophs can provide crucial information for understanding the harsh C-H activation of methane.Soluble methane monooxygenase(sMMO)belongs to the bacterial multi-component monooxygenase superfamily and requires hydroxylase(MMOH),regulatory(MMOB),and reductase(MMOR)components.Recent structural and biophysical studies have demonstrated that these components accelerate and retard methane hydroxylation in MMOH through protein-protein interactions.Complex structures of sMMO,including MMOH-MMOB and MMOH-MMOD,illustrate how these regulatory and inhibitory components orchestrate the di-iron active sites located within the four-helix bundles of MMOH,specifically at the docking surface known as the canyon region.In addition,recent biophysical studies have demonstrated the role of MmoR,aσ54-dependent transcriptional regulator,in regulating sMMO expression.This perspective article introduces remarkable discoveries in recent reports on sMMO components that are crucial for understanding sMMO expression and activities.Our findings provide insight into how sMMO components interact with MMOH to control methane hydroxylation,shedding light on the mechanisms governing sMMO expression and the interactions between activating enzymes and promoters.
基金Supported by Grants from the University of Buenos Aires, Buenos Aires, Argentina and CONICET, Buenos Aires, Argentina
文摘AIM： To study the effect of bilirubin on the oxidative liver status and the activity and expression of heine oxygenase-1 （HO-1） in rat liver injury induced by prehepatic portal hypertension. METHODS： Wistar male rats, weighing 200-250 g, were divided at random into two groups： one group with prehepatic portal hypertension （PH） induced by regulated prehepatic portal vein ligation （PPVL） and the other group corresponded to sham operated rats. Portal pressure, oxidative stress parameters, antioxidant enzymes, HO-1 activity and expression and hepatic sinusoidal vasodilatation were measured. RESULTS： In PPVL rats oxidative stress was evidenced by a marked increase in thiobarbituric acid reactive substances （TBARS） content and a decrease in reduced glutathione （GSH） levels. The activities of liver antioxidant enzymes, superoxide dismutase （SOD）, catalase （CAT） and glutathione peroxidase （GSH-Px） were also diminished while activity and expression of HO-1 were enhanced. Administration of bilirubin （5μmol/kg body weight） 24 h before the end of the experiment entirely prevented all these effects. Pretreatment with Sn-protoporphyrin IX （Sn-PPIX） （100 μg/kg body weight, i.p.）, a potent inhibitor of HO, completely abolished the oxidative stress and provoked a slight decrease in liver GSH levels as well as an increase in lipid peroxidation. Besides, carbon monoxide, another heme catabolic product, induced a significant increase in sinusoidal hepatic areas in PPVL group. Pretreatment of PPVL rats with Sn-PPIX totally prevented this effect CONCLUSION： These results suggest a beneficial role of HO-1 overexpression in prehepatic portal hypertensive rats.
基金Supported by The grants for Young Scientist Project,National Natural Science Foundation of China,No.30600598"Qi Ming Star for Young Scientist"Project,Science and Technology Commission of Shanghai Municipality,No.10QH1401800+3 种基金"Shu Guang Scholar"Project,Shanghai Municipal Educational Commission,No.10SG20Research and Innovation Project of Shanghai Municipal Education Commission,Project No.09YZ103the Key Medical Project of Science and Technology Commission of Shanghai Municipality,No.09411952500Nano-specific Project of Science and Technology Commission of Shanghai Municipality,Project No.0952nm03800
文摘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 stressresponse 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,itsroles 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.
基金grants from the National Institute of Health and by a grant from the Deutsche Forschungsgemeinschaft, No. FR 1644/4-1
文摘AIM： To investigate the effects of heme oxygenase-1 （HO-1） against oxidant-induced injury caused by bile duct ligation （BDL）.METHODS： Either cobalt protoporphyrin （CoPP）, a HO-1 inducer, or saline were injected intraperitoneally in male SD-rats. Three days later, BDL or sham-operations were performed. Rats were sacrificed 3 wk after BDL and livers were harvested for histology. Fibrosis was evaluated by sirius red staining and image analysis. Alpha-smooth muscular actin, which indicates activation of stellate cells, was detected by immunohistochemical staining, and q/tokine and collagen- Iα （Col- I α） mRNA expression was detected using RNase protection assays.RESULTS： Serum alanine transaminase increased 8-fold above normal levels one day after BDL. Surprisingly, enzyme release was not reduced in rats receiving CoPP. Liver fibrosis was evaluated 3 wk after BDL and the sirius red-positive area was found to be increased to about 7.8%. However, in CoPP pretreated rats sirius redpositive areas were increased to about 11.7% after BDL. Collagen-1 α and TGF-β mRNA increased significantly by BDL. Again, this effect was increased by HO-1 overexpression.CONCLUSION： Hepatic fibrosis due to BDL is not reduced by the HO-1 inducer CoPP. In contrast, HO-1 overexpression increases liver injury in rats under conditions of experimental chronic cholestasis.
基金Grants (ex 60%) from MURST (Ministero dell’ Università e della Ricerca Scientifica e Tecnologica),Rome,Italy
文摘Many physiological effects of natural antioxidants, their extracts or their major active components, have been reported in recent decades. Most of these compounds are characterized by a phenolic structure, similar to that of o-tocopherol, and present antioxidant properties that have been demonstrated both in vitro and in vivo. Polyphenors may increase the capacity of endogenous antioxidant defences and modulate the cellular redox state. Changes in the cellular redox state may have wide-ranging consequences for cellular growth and differentiation. The majority of in vitro and in vivo studies conducted so far have attributed the protective effect of bioactive polyphenols to their chemical reactivity toward free radicals and their capacity to prevent the oxidation of important intracellular components. However, in recent years a possible novel aspect inthe mode of action of these compounds has been suggested; that is, the ultimate stimulation of the heme oxygenase-1 （HO-1） pathway is likely to account for the established and powerful antioxidant/anti-inflammatory properties of these polyphenols. The products of the HO-catalyzed reaction, particularly carbon mon- oxide （CO） and biliverdin/bilirubin have been shown to exert protective effects in several organs against oxidative and other noxious stimuli. In this context, it is interesting to note that induction of HO-1 expression by means of natural compounds contributes to protection against liver damage in various experimental models. The focus of this review is on the significance of targeted induction of HO-1 as a potential therapeutic strategy to protect the liver against various stressors in several pathological conditions.
文摘Background Myocardial infarction （MI） has likely contributed to the increased prevalence of heart failure （HF）. As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi and damage to the intestinal barrier. The induction of heme oxygenase-1 （HO-1） could prevent, or lessen the effects of stress and inflammation. Thus, the effect and mechanism thereof of HO-1 on the intestines of rats with HF was investigated. Methods Male Wistar rats with heart failure through ligation of the left coronary artery were identified with an left ventricular ejection fraction of 〈 45% through echocardiography and then divided into various experimental groups based on the type of peritoneal injection they received [MI： saline; MI ＋ Cobalt protoporphyrin （CoPP）： CoPP solution; and MI ＋ Tin mesoporphyrin IX dichloride （SnMP）： SnMP solution]. The control group was comprised of rats without coronary ligation. Echocardiogra- phy was performed before ligation for a baseline and eight weeks after ligation in order to evaluate the cardiac function of the rats. The bac- terial translocation （BT） incidence, mesenteric microcirculation, amount of endotoxins in the vein serum, ileum levels of HO- 1, carbon oxide （CO）, nitric oxide （NO）, intedeuldn （IL）-10, turnour necrosis factor-et （TNF-ct）, and the ileum morphology were determined eight weeks after the operation. Results The rats receiving MI ＋ CoPP injections exhibited a recovery in cardiac function, an amelioration of mesenteric microcirculation and change in morphology, a lower BT incidence, a reduction in serum and ileac NO and TNF-ct levels, and an elevation in ileac HO-1, CO, and interleukin-10 （[L-10） levels compared to the MI group （P 〈 0.05）. The rats that received the MI ＋ SnMP injections exhibited results inverse to the MI （P 〈 0.05） group. Conclusions HO-1 exerted a protective effect on the intestines of rats with HF by inhibiting the inflammation and amelioration of microcirculation through the CO pathway. This protective effect could be independent from the recovery of cardiac function.
基金Supported by National Natural Science Foundation of China,No. 81071697Research Project of Health Bureau of Guangzhou City,No. 201102A213005 and 2010A30Research Project of Education Bureau of Guangzhou City,No. 10A192
文摘Heme oxygenase-1(HO-1) system catalyzes heme to biologically active products:carbon monoxide,biliverdin/bilirubin and free iron.It is involved in maintaining cellular homeostasis and many physiological and pathophysiological processes.A growing body of evidence indicates that HO-1 activation may play an important protective role in acute and chronic inflammation of gastrointestinal tract.This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal inflammation studied to date.The ability to upregulate HO-1 by pharmacological means or using gene therapy may offer therapeutic strategies for gastrointestinal inflammation in the future.
基金Supported by the Korean Research Foundation Grant(KRF-2004-005-200038)
文摘AIM: To examine the potency of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) as a hepatic heme oxygen-ase-1(HO-1) inducer and its regulation in HepG2 cells. METHODS: Expression of HO-1 and NF-E2-related factor 2 (Nrf2) and activation of mitogen-activated protein (MAP) kinases were analyzed by Western blot, immuno-fluorescence assay, and flow cytometry. Transfections of HO-1 gene, small interfering RNAs for HO-1 and Nrf2, and dominant-negative gene for MAP/extracellular signal-regulated kinase (ERK) were carried out to dissect the signaling pathways leading to HO-1 expression in HepG 2 cells. RESULTS: PGG up-regulated HO-1 expression and this expression conferred cytoprotection against oxidative injury induced by t-butyl hydroperoxide. Moreover, PGG induced Nrf2 nuclear translocation, which was found to be an upstream step of PGG-induced HO-1 expression, and ERK activation, of which pathway was involved in PGG-induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection. CONCLUSION: PGG up-regulates HO-1 expression by stimulating Nrf2 nuclear translocation in an ERK-depen-dent manner, and HO-1 expression by PGG may serve as one of the important mechanisms for its hepatoprotective effects.
基金Supported by The German Academic Exchange Program(DAAD,S.S.G.)
文摘AIM： To investigate the molecular mechanism and functional consequences of heme oxygenase-1 （HO-1） activation by lansoprazole in endothelial cells and macrophages. METHODS： Expression of HO-1 mRNA was analyzed by Northern blotting. Western blotting was used to determine the HO-1 and ferritin protein levels. NADPH-dependent reactive oxygen species （ROS） formation was measured with lucigenin-enhanced chemiluminescence. HO-1 promoter activity in mouse fibroblasts, stably transfected with a 15-kb HO-1 gene that drives expression of the reporter gene luciferase, was assessed usingin vivo bioluminescence imaging. RESULTS： Lansoprazole levels in endothelial cells increased HO-1 mRNA and HO-1 protein levels in macrophages. In addition, lansoprazole-induced ferritin protein levels in both cell systems. Moreover, induction of the antioxidant proteins HO-1 and ferritin by lansoprazole was followed by a decrease in NADPH- mediated ROS formation. The radical scavenging properties of lansoprazole were diminished in the presence of the HO inhibitor, chromium mesoporphyrin IX. Induction of HO-1 gene expression by lansoprazole was not related to oxidative stress or to the activation of the mitogen-activated protein kinase pathway. However, the phosphatidylinositol 3-kinase inhibitor LY294002 showed a concentration-dependent inhibition of HO-1 mRNA and promoter activity.CONCLUSION： Activation of HO-1 and ferritin may account for the gastric protection of lansoprazole and is dependent on a pathway blocked by LY294002.
基金Supported by Social Development Projects of Yunnan Province,No.2008CA026
文摘AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per group)into five groups:I/R group(4 h of liver cold ischemia followed by 6 h of reperfusion);heme oxygenase-1(HO-1)small interfering RNA(siRNA)group(injection of siRNA via donor portal vein 48 h prior to harvest);diazoxide(DZ) group(injection of DZ via donor portal vein 10 min prior to harvest);HO-1 siRNA+DZ group;and siRNA control group.Blood and liver samples were collected at 6 h after reperfusion.The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting,and tissue morphology was examined by light and transmission electron microscopy.Serum transaminases level and cytokines concentration were also measured.RESULTS:We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA+DZ group when compared with I/R group,while the increases were prominent in the DZ group.Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA+DZ groups compared with DZ group.Serum alanine aminotransferase,aspartate transaminase,tumor necrosis factor-αand interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA+DZ groups,and decreased in the DZ group.CONCLUSION:The protective effect of DZ may be induced by upregulation of HO-1.By inhibiting expression of HO-1,this protection pretreated with DZ was abolished.
文摘AIM:To investigate the effects of antithrombin Ⅲ(AT Ⅲ) injection via the portal vein in acute liver failure.METHODS:Thirty rats were intraperitoneally challenged with lipopolysaccharide(LPS) and D-galactosamine(GalN) and divided into three groups:a control group;a group injected with AT Ⅲ via the tail vein;and a group injected with AT Ⅲ via the portal vein.AT Ⅲ(50 U/kg body weight) was administrated 1 h after challenge with LPS and GalN.Serum levels of inflammatory cytokines and fibrin degradation products,hepatic fibrin deposition,and hepatic mRNA expression of hypoxiarelated genes were analyzed.RESULTS:Serum levels of alanine aminotransferase,tumor necrosis factor-α and interleukin-6 decreased significantly following portal vein AT Ⅲ injection compared with tail vein injection,and control rats.Portal vein AT Ⅲ injection reduced liver cell destruction and decreased hepatic fibrin deposition.This treatment also significantly reduced hepatic mRNA expression of lactate dehydrogenase and heme oxygenase-1.CONCLUSION:A clinically acceptable dose of AT Ⅲ injection into the portal vein suppressed liver damage,probably through its enhanced anticoagulant and antiinflammatory activities.
文摘AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN + pentobarbital sodium(PEN);2:LEAN + ISO;3:FAT + PEN;4:FAT + ISO.The animals were mechanically ventilated for 6 h.In vitro analyses of liver tissue included determination of HO-1 mRNA and protein expression as well as measurement of HO enzyme activity and immunohistochemical analyses.RESULTS:Compared to PEN treatment,ISO administration profoundly induced hepatic HO-1 mRNA and protein expression and significantly increased HO enzyme activity in lean Zucker rats.In contrast,no difference in HO-1 gene expression was observed after ISO or PEN anesthesia in obese Zucker rats.CONCLUSION:The present study demonstrates that ISO is an inducer of hepatic HO-1 gene expression in non-steatotic organs but failed to upregulate HO-1 in steatotic livers.
文摘It aims to analyze the impact heme oxygenase -1 （heme oxygenase 1, HO-1） on regulating factors of human hepatoma cell HepG2＇s cell cycle, through constructing recombinant vector of pcDNA3.1 containing wild-type and mutant HO-1 gene （＋）-wtHO-1 and pcDNA3.1 （＋）-mHO-1G143H. By using the method of liposome-mediated, the recombinant vector was transfected hepatoma cell line HepG2. And the transfected one with empty vector was treated as a control group. By the selection of G418, stable expression of wild-type and mutant HO-1 in HepG2 liver cancer cell lines were established. Use the blot of semi-quantitative RT-PCR and Western to test transfected cell lines expressing levels of riO-1 mRNA and protein. As HO-1 expression in stably transfected cell lines altered, we use Western blot to test transfected cell lines P21, P27 protein expression levels. As result shows, we got 1 HO-over-expression of wild-type and mutant in HepG2 cells; wild- type and mutant＇s over expression of HO-1 can induce the expression of tumor suppressor genes p21 and p27.we got the conclusion that HO-l＇s over-expression of tumor suppressor genes p21 and p27 is unrelated to the expression of heme decomposition products. HO-1 may regulate the expression of p21 and p27 through other mechanisms.
基金ThisprojectwassupportedbyagrantfromtheNationalNaturalScienceFoundationofChina (No 3 960 0 15 9)
文摘Objective To prepare rat heme oxygenase 1 (HO 1) mutants and to determine the activity and inhibition of this mutated enzyme Methods pcDNA3HO1 containing truncated native rat HO 1 cDNA and pcDNA3HO1Δ25 carrying mutated rat HO 1 cDNA (His25Ala) were constructed, respectively COS 1 cells transfected with pcDNA3HO1 and pcDNA3HO1Δ25 were collected and their activities were analyzed Results Native rat HO 1 was highly expressed in transfected cells and its activity was 13?688-15?600?U/mg protein per hour However, the enzyme activity of mutated HO 1 declined and the value was 1948-2160?U/mg protein per hour When an equal amount of mutant was added to the enzyme reaction system, the level of bilirubin decreased by 42% Conclusion The His25Ala mutant reduced the formation of bilirubin, suggesting that the mutant could competely bind the heme with native enzyme
