Heme oxygenase-1 as a therapeutic target in inflammatory disorders of the gastrointestinal tract

Heme oxygenase (HO)-1 is the inducible isoform of the first and rate-limiting enzyme of heme degradation. HO-1 not only protects against oxidative stress and apoptosis, but has received a great deal of attention in recent years because ofits potent anti-inflammatory functions. Studies with HO-1 knockout animal models have led to major advances in the understanding of how HO-1 might regulate inflammatory immune responses, although little is known on the underlying mechanisms. Due to its beneficial effects the targeted induction of this enzyme is considered to have major therapeutic po- tential for the treatment ofinflammatory disorders. This review discusses current knowledge on the mechanisms that mediate anti-inflammatory protection by HO-1. More specifically, the article deals with the role of HO-1 in the pathophysiology of viral hepatitis, inflammatorybowel disease, and pancreatitis. The effects of specific HO-1 modulation as a potential therapeutic strategy in experimental cell culture and animal models of these gastrointestinal disorders are summarized. In conclusion, targeted regulation of HO-1 holds major promise for future clinical interventions in inflammatory diseases of the gastrointestinal tract.

Rosmarinic acid elicits neuroprotection in ischemic stroke via Nrf2 and heme oxygenase 1 signaling

Rosmarinic acid（RA） can elicit a neuroprotective effect against ischemic stroke, but the precise molecular mechanism remains poorly understood. In this study, an experimental ischemic stroke model was established in CD-1 mice（Beijing Vital River Laboratory Animal Technology, Beijing, China） by occluding the right middle cerebral artery for 1 hour and allowing reperfusion for 24 hours. After intraperitoneally injecting model mice with 10, 20, or 40 mg/kg RA, functional neurological deficits were evaluated using modified Longa scores. Subsequently, cerebral infarct volume was measured using TTC staining and ischemic brain tissue was examined for cell apoptosis with TUNEL staining. Superoxide dismutase activity and malondialdehyde levels were measured by spectrophometry. Expression of heme oxygenase-1（HO-1）, nuclear factor erythroid 2-related factor 2（Nrf2）, Bcl-2, Bax, Akt, and phospho-Ser473 Akt proteins in ischemic brain tissue was detected by western blot, while mRNA levels of Nrf2, HO-1, Bcl-2, and Bax were analyzed using real time quantitative PCR. In addition, HO-1 enzyme activity was measured spectrophotometrically. RA（20 and 40 mg/kg） greatly improved neurological function, reduced infarct volume, decreased cell apoptosis, upregulated Bcl-2 protein and mRNA expression, downregulated Bax protein and mRNA expression, increased HO-1 and Nrf2 protein and mRNA expression, increased superoxide dismutase activity, and decreased malondialdehyde levels in ischemic brain tissue of model mice. However, intraperitoneal injection of a HO-1 inhibitor（10 mg/kg zinc protoporphyrin IX） reversed the neuroprotective effects of RA on HO-1 enzyme activity and Bcl-2 and Bax protein expression. The PI3 K/Akt signaling pathway inhibitor LY294002（10 mM） inhibited Akt phosphorylation, as well as Nrf2 and HO-1 expression. Our findings suggest that RA has anti-oxidative and anti-apoptotic properties that protect against ischemic stroke by a mechanism involving upregulation of Nrf2 and HO-1 expression via the PI3 K/Akt signaling pathway.

Assessment of heme oxygenase-1 （HO-1） activity in the cavernous tissues of sildenafil citrate-treated rats

Aim： To assess heine oxygenase-1 （HO-1） activity in the cavemous tissue of sildenafil citrate-treated rats. Methods： One hundred and ninety-two Sprague-Dawley male rats, divided into four equal groups, were investigated. Group 1, the control group, received regular animal chow; group 2 received sildenafil citrate by intragastric tube; group 3 received sildenafil and HO inhibitor （zinc protoporphyrin, ZnPP）; and group 4 received sildenafil and nitric oxide synthase （NOS） inhibitor L-nitroarginine methyl ester （L-NAME）. Twelve rats from each group were killed after 0.5 h, 1 h, 2 h and 3 h of drug administration. Then HO-1 activity, cGMP levels and NOS enzymatic activity in the cavernous tissues were estimated. Results： In cavemous tissue, HO-1 activity, NOS enzymatic activity and cGMP concentration increased significantly in sildenafil-treated rats compared to other groups throughout the experiment. Rats receiving either HO or NOS inhibitors showed a significant decrease in these parameters. HO- 1 cavemous tissue activity and NOS enzymatic activity demonstrated a positive significant correlation with cGMP levels （r = 0.646, r = 0.612 respectively; P 〈 0.001）. Conclusion： The actions of PDE5 inhibitor sildenafil citrate in the cavernous tissue are partly mediated through the interdependent relationship between both HO-1 and NOS activities.

Existence of Heme Oxygenase-carbon Monoxide-cyclic Guanosine Monophosphate Pathway in Human Trabecular Meshwork Cells In Vitro

To confirm the existence of heme oxygenase (HO)-carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HTMCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR) was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA levels were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry. Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA, HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.

Region-dependent effects of diabetes and insulin-replacement on neuronal nitric oxide synthase-and heme oxygenase-immunoreactive submucous neurons

AIM To investigate the intestinal segment-specific effects of diabetes and insulin replacement on the density of different subpopulations of submucous neurons. METHODS Ten weeks after the onset of type 1 diabetes samples were taken from the duodenum, ileum and colon of streptozotocin-induce diabetic, insulin-treated diabetic and sex-and age-matched control rats. Whole-mount preparations of submucous plexus were prepared from the different gut segments for quantitative fluorescent immunohistochemistry. The following double-immunostainings were performed: neuronal nitric oxide synthase(n NOS) and Hu C/D, heme oxygenase(HO) 1 and peripherin, as well as HO2 and peripherin. The density of n NOS-, HO1-and HO2-immunoreactive(IR) neurons was determined as a percentage of the total number of submucous neurons. RESULTS The total number of submucous neurons and the proportion of n NOS-, HO1-and HO2-IR subpopulations were not affected in the duodenal ganglia of control, diabetic and insulin-treated rats. While the total neuronal number did not change in either the ileum or the colon, the density of nitrergic neurons exhibited a 2-and 3-fold increase in the diabetic ileum and colon, respectively, which was further enhanced after insulin replacement. The presence of HO1-and HO2-IR submucous neurons was robust in the colon of controls(38.4%-50.8%), whereas it was significantly lower in the small intestinal segments(0.0%-4.2%, P < 0.0001). Under pathophysiological conditions the only alteration detected was an increase in the ileum and a decrease in the colon of the proportion of HO-IR neurons in insulin-treated diabetic animals. CONCLUSION Diabetes and immediate insulin replacement induce the most pronounced region-specific alterations of n NOS-, HO1-and HO2-IR submucous neuronal density in the distal parts of the gut.

Biochanin A attenuates spinal cord injury in rats during early stages by inhibiting oxidative stress and inflammasome activation

Previous studies have shown that Biochanin A,a flavonoid compound with estrogenic effects,can serve as a neuroprotective agent in the context of cerebral ischemia/reperfusion injury;howeve r,its effect on spinal cord injury is still unclea r. In this study,a rat model of spinal cord injury was established using the heavy o bject impact method,and the rats were then treated with Biochanin A(40 mg/kg) via intrape ritoneal injection for 14 consecutive days.The res ults showed that Biochanin A effectively alleviated spinal cord neuronal injury and spinal co rd tissue injury,reduced inflammation and oxidative stress in spinal cord neuro ns,and reduced apoptosis and pyroptosis.In addition,Biochanin A inhibited the expression of inflammasome-related proteins(ASC,NLRP3,and GSDMD)and the Toll-like receptor 4/nuclear factor-κB pathway,activated the Nrf2/heme oxygenase 1 signaling pathway,and increased the expression of the autophagy markers LC3 Ⅱ,Beclin-1,and P62.Moreove r,the therapeutic effects of Biochanin A on early post-s pinal cord injury were similar to those of methylprednisolone.These findings suggest that Biochanin A protected neurons in the injured spinal cord through the Toll-like receptor 4/nuclear factor κB and Nrf2/heme oxygenase 1 signaling pathways.These findings suggest that Biochanin A can alleviate post-spinal cord injury at an early stage.

Upregulation of CDGSH iron sulfur domain 2 attenuates cerebral ischemia/reperfusion injury

CDGSH iron sulfur domain 2 can inhibit ferroptosis,which has been associated with cerebral ischemia/reperfusion,in individuals with head and neck cancer.Therefore,CDGSH iron sulfur domain 2 may be implicated in cerebral ischemia/reperfusion injury.To validate this hypothesis in the present study,we established mouse models of occlusion of the middle cerebral artery and HT22 cell models of oxygen-glucose deprivation and reoxygenation to mimic cerebral ischemia/reperfusion injury in vivo and in vitro,respectively.We found remarkably decreased CDGSH iron sulfur domain 2 expression in the mouse brain tissue and HT22 cells.When we used adeno-associated virus and plasmid to up-regulate CDGSH iron sulfur domain 2 expression in the brain tissue and HT22 cell models separately,mouse neurological dysfunction was greatly improved;the cerebral infarct volume was reduced;the survival rate of HT22 cells was increased;HT22 cell injury was alleviated;the expression of ferroptosis-related glutathione peroxidase 4,cystine-glutamate antiporter,and glutathione was increased;the levels of malondialdehyde,iron ions,and the expression of transferrin receptor 1 were decreased;and the expression of nuclear-factor E2-related factor 2/heme oxygenase 1 was increased.Inhibition of CDGSH iron sulfur domain 2 upregulation via the nuclear-factor E2-related factor 2 inhibitor ML385 in oxygen-glucose deprived and reoxygenated HT22 cells blocked the neuroprotective effects of CDGSH iron sulfur domain 2 up-regulation and the activation of the nuclear-factor E2-related factor 2/heme oxygenase 1 pathway.Our data indicate that the up-regulation of CDGSH iron sulfur domain 2 can attenuate cerebral ischemia/reperfusion injury,thus providing theoretical support from the perspectives of cytology and experimental zoology for the use of this protein as a therapeutic target in patients with cerebral ischemia/reperfusion injury.

Auxin induces lateral root formation in Bupleurum: A heme oxygenase dependent approach

Objective: The content of saikosaponins in genus Bupleurum is increased with numbers of lateral root, but the genetic mechanisms are largely unknown. This study aims to identify the heme oxygenase(HO) gene family members of B. chinense and B. scorzonerifolium, and assess their role in the root development in Bupleurum.Methods: The gene sequences of HO family were selected from iso-seq full-length transcriptome data of B. chinense and B. scorzonerifolium, and were analyzed in physicochemical properties, conserved domains,motifs and phylogenetic relationship. In addition, the expression patterns of HO gene in different parts of roots were compared via transcriptome sequencing and qRT-PCR in the two species.Results: Five Bupleurum HO genes(BcHO1-BcHO5) belonging to the HO1 subfamily were identified from the transcriptome data, whereas the HO_(2) subfamily member was not identified. The expression levels of BcHO1 and BcHO_(2) were significantly higher than those of other three HO members in the transcriptome analysis. In addition, the expression profile of BcHO1 showed consistency with lateral root development in B. chinense and B. scorzonerifolium.Conclusion: Hos might participate in the auxin-induced morphogenesis of lateral roots. The yield of saikosaponin may be improved by manipulating expression of these genes.

Endogenous Hydrogen Peroxide Plays a Positive Role in the Upregulation of Heme Oxygenase and Acclimation to Oxidative Stress in Wheat Seedling Leaves

Pretreatment of lower H2O2 doses （0.05, 0.5 and 5 mM） for 24 h was able to dose-dependently attenuate lipid peroxidation in wheat seedling leaves mediated by further oxidative damage elicited by higher dose of H2O2 （150 mM） for 6 h, with 0.5 mM H2O2 being the most effective concentrations. Further results illustrated that 0.5 mM H2O2 pretreatment triggered the biphasic production of H2O2 during a 24 h period. We also noticed that only peak Ⅰ （0.25 h） rather than peak Ⅱ （4 h） was approximately consistent with the enhancement of heme oxygenase （HO） activity, HO-1 gene expression. Meanwhile, enhanced superoxide dismutase （SOD） activity, Mn-SOD and Cu, Zn-SOD transcripts might be a potential source of peak Ⅰ of endogenous H2O2. Further results confirmed that 0.5 mM H2O2 treatment for 0.5 h was able to upregulate HO gene expression, which was detected by enzyme activity determination, semi-quantitative reverse transcription-polymerase chain reaction and western blotting. Meanwhile, the application of N,N＇-dimethylthiourea, a trap for endogenous H2O2, not only blocked the upregulation of HO, but also reversed the corresponding oxidation attenuation. Together, the above results suggest that endogenous H2O2 production （peak Ⅰ） plays a positive role in the induction of HO by enhancing its mRNA level and protein expression, thus leading to the acclimation to oxidative stress.

Heme oxygenase-1 polymorphism associated with severity of chronic obstructive pulmonary disease

Background Recent studies have suggested that susceptibility to chronic obstructive pulmonary disease （COPD） might be related to the length polymorphism of （GT）n repeat in the 5＇-flanking region of heme oxygenase-1 （HOX-1） gene. However, there has been no research about the relationship between the polymorphism of HOX-1 gene and severity of COPD. Methods The polymorphism of HOX-1 gene in 452 patients with COPD from Han population in Southwest China was analysed by fragment analysis. The frequencies of the HOX-1 genotype were compared with the stage of COPD of each patient. Results The HOX-1 genotypes were classified into two groups： group I were individuals with class L allele （the number of GT 〉32 repeats）, and group II were those without class L allele （the number of GT 〈32 repeats）. The genotypic frequency of the HOX-1 group I was significantly higher than group II in the very severe COPD patients （36.8% vs 22.4%, P〈0.01, OR=2.0, 95% CI 1.3-3.1）, while the genotypic frequency of the HOX-1 group II was lower in the mild COPD （16.0% vs 26.0%, P=-0.02, OR=0.5, 95% CI 0.3-0.9）. However, in moderate and severe stages COPD, there were similar genotypic frequencies between HOX-1 group Ⅰ and group Ⅱ. Conclusions Genetic polymorphism in HOX-1 is associated with the severity of COPD in Southwest China. COPD patients with class L allele may be susceptible to develop very severe COPD. Conversely, the COPD patients without class L allele may be more easily stabilized on mild COPD.

Effect of fusion protein TAT and heme oxygenase-1 on liver sinusoidal endothelial cells apoptosis during preservation injury

Background Proteins or peptides can be directly transferred into cells when covalently linked to protein transduction domains （PTDs）. TAT is one of the most widely studied PTDs. The effect of fusion protein TAT and heme oxygenase-1 （HO-1） on liver sinusoidal endothelial cells （SECs） apoptosis during cold storage is unknown. The present study aimed to determine whether fusion protein TAT-HO-1 would transduce efficiently into liver during cold storage, and, if so, to determine whether TAT-HO-1 would attenuate SECs apoptosis during preservation injury in rat. Methods Livers of Sprague-Dawley rats were harvested and randomly assigned to group 1 （HTK solution） and group 2 （HTK solution containing TAT-HO-1 fusion protein） according to the type of the preservation solution. The transduction efficiency of TAT-HO-1 was examined and the impairment of SECs was assessed during the period of cold storage followed by 1 hour of reperfusion. Results TAT-HO-1 can transduce efficiently into liver during cold storage. A significantly lower apoptotic index of SECs was observed in group 2, at 6, 12 and 18 hours of cold storage after 1 hour reperfusion, when compared with group 1. TAT-HO-1 reduced HA and ET levels in liver at each time point. Both Bcl-2 and Bax protein were expressed in hepatocytes and SECs at the periphery of the sinusoidal space. Moreover, higher Bcl-2 expression and lower Bax expression were observed in group 2. Conclusions TAT-HO-1 can transduce efficiently into rat livers and shows a protective effect on SECs by attenuating apoptosis during cold ischemia/reperfusion injury. Protein transduction will be a novel therapeutic strategy to reduce the risk of preservation injury in liver transplantation.

Chinese herbal medicine compound Yi-Zhi-Hao pellet inhibits replication of influenza virus infection through activation of heme oxygenase-1

As a leading cause of respiratory disease, influenza A virus(IAV) presents a pandemic threat in annual seasonal outbreaks. Given the limitation of existing anti-influenza therapies, there remains to be a requirement for new drugs. Compound Yi-Zhi-Hao pellet(CYZH) is a famous traditional Chinese medicine(TCM) used in the clinic, whose formula has been recorded in Complication of National Standard for Traditional Chinese Medicine to treat common cold. In this study, we found that CYZH exhibited a broad-spectrum anti-influenza activity and inhibited the expression of viral RNA and proteins in vitro. Mechanistically, CYZH had no inhibitory activities against viral protein hemagglutinin and IAV RNA-dependent RNA polymerase. Instead, it induced activation of erythroid 2-related factor 2(Nrf2) and nuclear factor kappa B(NF-κB), which subsequently upregulated heme oxygenase-1(HO-1) expression.Also, CYZH protected cells from oxidative damage induced by reactive oxygen series. In conclusions,CYZH inhibits IAV replication in vitro, at least partly by activating expression of the Nrf2/HO-1 pathway.

The Role of Endogenous Carbon Monoxide in the Hypoxic Vascular Remodeling of Rat Model of Hypoxic Pulmonary Hypertension

We investigated the expression of heme oxygenase 1 (HO 1) gene and production of endogenous carbon monoxide (CO) in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin on the expression of HO 1 gene and pulmonary hypertension. A rat model of hypoxic pulmonary hypertension was recreated by exposure to intermittent normobaric hypoxic environment (10 % O 2). Reverse transcriptase polymerase chain reaction (RT PCR) was performed to determine the level of HO 1 mRNA in the rat lung tissue and double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood. Cardiac catheterization was employed to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathological changes of the intra acinar pulmonary arteries (IAPA). It was found that (1) There was a low level of HO 1 mRNA in normal rat lung tissue, but the level of HO 1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats ( P <0.01). The quantity of COHb was 2-3 times those of control group ( P <0.01 or P <0.05). These were accompanied by the increased of RVSP and the thickened IAPA; (2) Hemin could keep the HO 1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, thereby ameliorating the pathological changes of IAPA. In conclusion, the upregulation of the expression of HO 1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.

Febrile seizure, but not hyperthermia alone, induces the expression of heme oxygenase-1 in rat cortex

Background Febrile seizure （FS） is the most common seizure disorders. Approximately one third of children with a febrile seizure have recurrent events. The mechanism of FS remains unclear. Heme oxygenase-1 （HO-1） is a member of the heat shock proteins family and can be induced in the brain by various stresses, including hyperthemia and seizure. This study aimed at investigating the changes of HO-1 in the cortex of rats after recurrent FS. Methods FS in rats was induced ten times, once every 2 days. In a bath of warm water, developing rats were randomly divided into two groups： control group （n=16） and warm water-treated group （n=50）. The latter group was subdivided into hyperthermia group （n=19） and FS group （n=23）. The expression and content of HO-1 mRNA in cortex were observed using in situ hybridization and quantitative reverse transcription-polymerase chain reaction （RT-PCR）. The content of HO- 1 protein in cortex was measured using Western blotting. Results HO-1 mRNA expression of cortex neurons in FS group was markedly increased in comparison with those in hyperthermia and control groups （P=0.00）, however, there was no statistic difference bftween hyperthermia group and control group （P=0.16）. The relative amount of HO- 1 mRNA in cortex in FS group was increased by 53.13% and 96% in comparison with those in hyperthermia group and control group respectively （P=0.00）, but there was no obvious difference between the later two groups （P=0.051）. Western blotting analysis showed that the HO-1 protein content in cortex in FS group was increased by 198% and 246% in comparison with those in hyperthermia group and control group respectively （P=0.00）. There was no obvious difference in HO-1 protein content between the later two groups （P=0.09）. Conclusions Recurrent FS in rats can cause the increase of HO-1 mRNA and protein in cortex which may be involved in the mechanism of FS. The short-time recurrent hyperthermia can not induce the increase of HO-1 mRNA and protein.

Hemin-induced increase in saponin content contributes to the alleviation of osmotic and cold stress damage to Conyza blinii in a heme oxygenase 1-dependent manner

Hemin can improve the stress resistance of plants through the heme oxygenase system.Additionally,substances contained in plants,such as secondary metabolites,can improve stress resistance.However,few studies have explored the effects of hemin on secondary metabolite content.Therefore,the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study.Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C.blinii under osmotic stress and cold stress.Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C.blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway,thus increasing the saponin content.Moreover,the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX(ZnPPIX).This study revealed that hemin can increase the saponin content of C.blinii and alleviate the damage caused by abiotic stress,and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.

D-GalN/LPS诱导大鼠急性肝衰竭中髓过氧化物酶和 Nrf2/HO-1信号通路的变化

目的 探讨D-氨基半乳糖(D-GalN)/脂多糖(LPS)诱导急性肝衰竭(acute liver failure,ALF)大鼠中髓过氧化物酶(myeloperoxidase,MPO)和核因子E2相关因子2(Nrf2)/血红素氧合酶-1(HO-1)信号通路的变化及ALF的发生机制。方法 SD大鼠随机分为对照组和ALF组。ALF组:将D-GalN 800 mg/kg和LPS 8μg/只同时腹腔注射,于注射后6、12和24 h检测血清总胆红素(TBiL)、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)含量。ELISA法检测血清MPO、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平,比色法测定MPO活性,RT-PCR检测肝组织Nrf2和HO-1的mRNA水平,Western blot法检测肝组织MPO、Nrf2和HO-1蛋白水平。结果 与对照组比较,ALF组血清MPO水平于造模后6 h升高,12 h为最高,24 h开始下降(23.33±2.06 vs.33.00±3.16,65.75±7.02,53.92±5.63,P<0.05);血清TNF-α(11.30±3.26 vs.102.17±14.80,83.33±11.22,64.25±9.29,P<0.01)和IL-6(10.83±2.92 vs.89.25±10.86,77.33±8.02,65.58±7.31,P<0.01)于造模后6 h升高最明显,12 h后逐渐下降,差异均有统计学意义。ALF组6、12、24 h肝组织MPO活性高于对照组,差异均有统计学意义(15.5±1.51,28.08±4.65,22.92±1.93 vs.12.17±1.27,P<0.05);ALF组肝组织6、12、24 h Nrf2 mRNA(1.59±0.13,3.65±0.11,2.35±0.11 vs.1.04±1.01,P<0.01)和HO-1 mRNA(2.44±0.19,4.77±0.18,3.82±0.17 vs.1.12±0.06,P<0.01)水平高于对照组,差异均有统计学意义。ALF组肝组织MPO(4.10±0.70,9.77±1.15,7.23±0.40 vs.2.07±0.42,P<0.01)、Nrf2(4.03±0.80,9.03±0.50,6.07±0.47 vs.2.63±0.38,P<0.01)和HO-1(1.73±0.21,5.17±0.51,3.03±0.32 vs.0.97±0.21,P<0.01)蛋白表达于12 h达最高值,ALF组各时间点与对照组比较均差异有统计学意义。结论 MPO可能通过氧化应激和炎症反应影响Nrf2/HO-1信号通路,在ALF中发挥重要作用。

The microsatellite polymorphism of heme oxygenase-1 is associated with baseline plasma IL-6 level but not with restenosis after coronary in-stenting

Background Vascular smooth muscle cells （VSMCs） can express heme-oxygenase （HO）, a rate-limiting enzyme in the degradation of heme to bilirubin, ferritin and carbon monoxide （ CO）. VSMC-derived CO can suppress VSMC proliferation and may serve as an antiproliferation factor. The promoter region of HO-1 shows a polymorphism with different （GT）n repeats that has been reported to differently induce gene expression. The objective of this study was to examine the effect of this variation on the occurrence of restenosis after in-stent treatment in patients with coronary artery disease. Methods Candidates who underwent coronary stent implantation were genotyped for the HO-1 promoter polymorphism using polymerase chain reaction （PCR） and automated DNA capillary sequencer. Serum levels of IL-6 and C-reactive protein （CRP） were obtained at baseline, 24 hours and 48 hours after stenting. The primary end point for the study was angiographic evidence of in-stent restenosis at 6 months. All parameters for evaluation of restenosis were analysed by quantitatve computer-assisted angiographic analysis （QCA）. Results One hundred and eighty-seven patients who underwent coronary stent implantation were studied of whom 27.8% showed 〉150% restenosis after 6 months. The distribution of （GT）n repeats of all patients in the promoter region of HO-1 genotype ranged from 22 to 42, with （GT） 25 and （GT） 32 being the two most common alleles. The allelic repeats were divided into the short class （S） with 29 （ GT）., the middle class （M） with 30- 37 （GT）n and the long class （L） with 38 （GT）n. There was no significant difference in the restenosis between the genotype groups or between post operation levels of inflammation markers, but carriers of the S allele （ n = 120） had 33.3% lower baseline IL-6 compared with non-S carriers （n =67, P =0. 0008）. Conclusions Although no association was observed between the HO-1 promoter polymorphism and coronary in-stent restenosis following the stent procedure, the association with plasma IL-6 levels suggests that HO-1 S allele might protect from the atherosclerotic inflammatory process.

Carbon monoxide contributes to the constipating effects of granisetron in rat colon

AIM To investigate the mechanisms underlying the potential contribution of the heme oxygenase/carbon monoxide(HO/CO) pathway in the constipating effects of granisetron. METHODS For in vivo studies, gastrointestinal motility was evaluated in male rats acutely treated with granisetron [25, 50, 75 μg/kg/subcutaneous(sc)], zinc protoporphyrin IX [Zn PPIX, 50 μg/kg/intraperitoneal(ip)] and hemin(50 μmol/L/kg/ip), alone or in combination. For in vitro studies, the contractile neurogenic response to electrical field stimulation(EFS, 3, 5, 10 Hz, 14 V, 1 ms, pulse trains lasting 10 s), as well as the contractile myogenic response to acetylcholine(ACh, 0.1-100 μmol/L) were evaluated on colon specimens incubated with granisetron(3 μmol/L, 15 min), Zn PPIX(10 μmol/L, 60 min) or CO-releasing molecule-3(CORM-3, 100, 200, 400 μmol/L) alone or in combination. These experiments were performed under co-treatment withor without atropine(3 μmol/L, a muscarinic receptor antagonist) or NG-nitro-L-Arginine(L-NNA, 100 μmol/L, a nitric oxide synthase inhibitor).RESULTS Administration of granisetron(50, 75 μg/kg) in vivo significantly increased the time to first defecation(P = 0.045 vs vehicle-treated rats), clearly suggesting a constipating effect of this drug. Although administration of Zn PPIX or hemin alone had no effect on this gastrointestinal motility parameter, Zn PPIX co-administered with granisetron abolished the granisetron-induced constipation. On the other hand, co-administration of hemin and granisetron did not modify the increased constipation observed under granisetron alone. When administered in vitro, granisetron alone(3 μmol/L) did not significantly modify the colon's contractile response to either EFS or ACh. Incubation with Zn PPIX alone(10 μmol/L) significantly reduced the colon's contractile response to EFS(P = 0.016) but had no effect on contractile response to ACh. Co-administration of Zn PPIX and atropine(3 μmol/L) abolished the Zn PPIX-mediated decrease in contractile response to EFS. Conversely, incubation with CORM-3(400 μmol/L) alone increased both the contractile response to EFS at 10 Hz(10 Hz: 71.02 ± 19.16 vs 116.25 ± 53.70, P = 0.01) and the contractile response to ACh(100 μmol/L)(P = 0.012). Co-administration of atropine abolished the CORM-3-mediated effects on the EFS-mediated response. When granisetron was co-incubated in vitro with ZnP PIX, the ZnP PIX-mediated decrease in colon contractile response to EFS was lost. On the other hand, co-incubation of granisetron and CORM-3(400 μmol/L) further increased the colon's contractile response to EFS(at 5 Hz: P = 0.007; at 10 Hz: P = 0.001) and to ACh(ACh 10 μmol/L: P = 0.001; ACh 100 μmol/L: P = 0.001) elicited by CORM-3 alone. L-NNA co-administered with granisetron and CORM-3 abolished the potentiating effect of CORM-3 on granisetron on both the EFSinduced and ACh-induced contractile response.CONCLUSION Taken together, findings from in vivo and in vitro studies suggest that the HO/CO pathway is involved in the constipating effects of granisetron.

Huangqin Decoction Delays Progress of Colitis-Associated Carcinogenesis by Regulating Nrf2/HO-1 Antioxidant Signal Pathwayin Mice

Objective:To investigate the effect of Huangqin Decoction(HQD)on nuclear factor erythroid 2 related-factor 2(Nrf2)/heme oxygenase(HO-1)signaling pathway by inducing the colitis-associated carcinogenesis(CAC)model mice with azoxymethane(AOM)/dextran sodium sulfate(DSS).Methods:The chemical components of HQD were analyzed by liquid chromatography-quadrupole-time-of-flight mass spectrometry(LC-Q-TOF-MS/MS)to determine the molecular constituents of HQD.Totally 48 C57BL/6J mice were randomly divided into 6 groups by a random number table,including control,model(AOM/DSS),mesalazine(MS),low-,medium-,and high-dose HQD(HQD-L,HQD-M,and HQD-H)groups,8 mice in each group.Except for the control group,the mice in the other groups were intraperitoneally injected with AOM(10 mg/kg)and administrated with 2.5%DSS orally for 1 week every two weeks(totally 3 rounds of DSS)to construct a colitis-associated carcinogenesis mouse model.The mice in the HQD-L,HQD-M and HQD-H groups were given HQD by gavage at doses of 2.925,5.85,and 11.7 g/kg,respectively;the mice in the MS group was given a suspension of MS at a dose of 0.043 g/kg(totally 11 weeks).The serum levels of malondialdehyde(MDA)and superoxide dismutase(SOD)were measured by enzyme-linked immunosorbent assay.The mRNA and protein expression levels of Nrf2,HO-1,and inhibitory KELCH like ECH-related protein 1(Keap1)in colon tissue were detected by quantitative real-time PCR,immunohistochemistry,and Westem blot,respectively.Results:LC-Q-TOF-MS/MS analysis revealed that the chemical constituents of HQD include baicalin,paeoniflorin,and glycyrrhizic acid.Compared to the control group,significantly higher MDA levels and lower SOD levels were observed in the model group(P<0.05),whereas the expressions of Nrf2 and HO-1 were significantly decreased,and the expression of Keap1 increased(P<0.01).Compared with the model group,serum MDA level was decreased and SOD level was increased in the HQD-M,HQD-H and MS groups(P<0.05).Higher expressions of Nrf2 and HO-1 were observed in the HQD groups.Conclusion:HQD may regulate the expression of Nrf2 and HO-1 in colon tissue,reduce the expression of MDA and increase the expression of SOD in serum,thus delaying the progress of CAC in AOM/DSS mice.