OBJECTIVETo investigate the effect of intracellular 5-lipoxygenase on oxidation of benzidine in HBE cells and to provide further evidence that lipoxygenase is an alternative pathway for the oxidation of xenobiotics mediated by cytochrome P450.

METHODSEnzyme system test: Soybean lipoxygenase (SLO), substrate (benzidine) and other components reacted in the enzyme system, followed by detection of the reaction products by spectrophotometry. In vitro test: After HBE cells were exposed to benzidine, the protein levels of 5-lipoxygenase in HBE cells were assessed by Western-blot, and the DNA damage by the single cell gel electrophoresis. At last, the effect of the specific inhibitor of 5-lipoxygenase (AA861) on 5-lipoxygenase protein expression and DNA damage in HBE cells were detected.

RESULTSSLO could catalyze the co-oxidation of benzidine to generate benzidine diimine in the presence of hydrogen peroxide. Under optimal condition, numax value of the oxidation of benzidine catalyzed by SLO was 1.42 nmol*min(-1) SLO, and the Km value of benzidine was 1.48 mmol/L. EGCG could inhibit the oxidation of benzidine by SLO. Benzidine could induce 5-lipoxygenase protein expression in HBE cells, but AA861 was invalid. Benzidine caused DNA damage in HBE cells, which could be significantly inhibited by AA861.

CONCLUSION5-LOX protein expression in HBE cells can be regulated by benzidine, which suggests that the co-oxidation of benzidine by 5-LOX could produce into electrophile that could covalently bind to DNA and induce DNA damage, which could be one of the mechanisms for carcinogenesis of BZD. 5-LOX inhibitor AA861 can inhibit this effect.

Arachidonate 5-Lipoxygenase ; metabolism ; Benzidines ; pharmacokinetics ; toxicity ; Cells, Cultured ; DNA Damage ; drug effects ; Epithelial Cells ; drug effects ; enzymology ; metabolism ; Humans

OBJECTIVETo determine whether 5-lipoxygenase (5-LOX) is involved in rotenone-induced injury in PC12 cells, which is a cell model of Parkinson disease.

METHODSAfter rotenone treatment for various durations, cell viability was determined by colorimetric MTT reduction assay, and 5-LOX translocation was detected by immunocytochemistry. The effect of 5-LOX inhibitor zileuton was also investigated.

RESULTRotenone (0.3-30 μmol/L) induced PC12 cell injury, and zileuton (3-100 μmol/L) attenuated this injury. Rotenone also time-and concentration-dependently induced 5-LOX translocation into the nuclear envelope, and zileuton (1-30 μmo/L) significantly inhibited rotenone-induced 5-LOX translocation.

CONCLUSION5-LOX is involved in rotenone-induced injury in PC12 cells, and 5-LOX inhibitor zileuton can reduce rotenone-induced 5-LOX activation and cell injury.

Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; physiology ; Cell Survival ; drug effects ; Hydroxyurea ; analogs & derivatives ; pharmacology ; Lipoxygenase Inhibitors ; pharmacology ; PC12 Cells ; Rats ; Rotenone ; pharmacology

Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; Brain Diseases ; enzymology ; metabolism ; Disease Models, Animal ; Histamine ; metabolism ; Humans ; Membrane Proteins ; metabolism ; Receptors, Histamine ; metabolism ; Receptors, Leukotriene ; metabolism

OBJECTIVETo determine whether oxygen-glucose deprivation (OGD) induces C6 cell injury, and whether 5-lipoxygenase (5-LOX)/cysteinyl leukotriene (CysLT) pathway is involved in OGD-induced injury.

METHODSAfter OGD treatment and recovery for various durations, the viability of C6 cells was determined, and the effects of 5-LOX inhibitors and CysLT receptor antagonists were investigated. Intracellular distribution of 5-LOX protein was detected by immunocytochemistry, and the mRNA expressions of CysLT1 and CysLT2 receptors were detected by RT-PCR. The effect of leukotriene D(4) (LTD(4)) on C6 cells was also investigated.

RESULTOGD for 4-8 h followed by recovery for 24-72 h significantly induced C6 cell injury. Neither 5-LOX inhibitors nor CysLT receptor antagonists inhibited OGD-induced injury. OGD did not induce 5-LOX translocation into the nuclear membrane. C6 cells highly expressed CysLT(2) receptor, but the expression of CysLT1receptor was much weaker; the expression was not affected by OGD. In addition, LTD(4) did not affect C6 cells significantly.

CONCLUSIONOGD can induce C6 cell injury, but 5-LOX/CysLT pathway might be not involved in OGD-induced injury.

Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; Cell Hypoxia ; physiology ; Glioma ; pathology ; Glucose ; metabolism ; Rats ; Receptors, Leukotriene ; metabolism ; Signal Transduction ; physiology ; Tumor Cells, Cultured

BACKGROUND AND OBJECTIVES: A recent study has demonstrated a possible involvement of leukotriene C4 synthase (LTC4S) gene polymorphism in ASA-intolerant asthma (AIA) in a Polish population, while no significances were noted in other populations. To investigate the role of genetic polymorphism in AIA development, we screened single nucleotide polymorphisms (SNPs) for the key enzymes involved in arachidonate metabolism, and cysteinyl leukotriene receptor 1 (CYSLTR1) in a larger scale of Korean population with AIA. MATERIALS AND METHODS: 93 AIA and 181 ASA-tolerant asthma (ATA) patients, and 123 normal controls (NC) were enrolled. Single base extension method was applied for genotyping of SNPs in 5-lipoxygenase (ALOX5, -1708G>A, 21C>T, 270G>A, 1728G>A), ALOX5 activating protein (FLAP, 218A>G), cyclooxygenase 2 (COX2, -162C>G, 10T>G, 228G>A), LTC4S (-444A>C), and CYSLTR1 (927T>C). Haplotype analyses for ALOX5 were performed as well. RESULTS: There were no significant differences in allele and genotype frequencies of the SNPs among the three groups (p>0.05). However, the frequency of ALOX5-ht1[G-C-G-A] containing genotype in the AIA group was significantly higher than those of the ATA group (p=0.01, OR =5.0, 95%CI=1.54-17.9) and the normal controls (p=0.03, OR=4.5, 95%CI=1.1-18.4) with a dominant model. CONCLUSION: These results suggest a lack of association between FLAP, COX2, LTC4S, and CYSLTR1 gene polymorphisms, and AIA phenotype in Korean population. However, a possible involvement of ALOX5-ht1[G-C-G-A] in AIA development was suggested.
Alleles ; Arachidonate 5-Lipoxygenase* ; Aspirin ; Asthma* ; Cyclooxygenase 2 ; Genotype ; Haplotypes* ; Humans ; Leukotriene C4 ; Metabolism ; Phenotype ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptors, Leukotriene

OBJECTIVETo examine the association of 5-lipoxygenase (5-LOX) expression with clinicopathological factors in colorectal cancer.

METHODSImmunohistochemical stain was used to detect the 5-LOX expression in 52 resected specimens of colorectal cancer. The association between 5-LOX expression and clinicopathological factors was examined.

RESULTSThe positive rate of 5-LOX expression in 52 specimens of colorectal carcinoma was 73.1% (38/52). In 41 colorectal cancer specimens with lymph node metastasis, the positive rate of 5-LOX expression was higher than that in the specimens without metastasis (87.8% vs. 18.2%, P<0.05). The positive rate of 5-LOX expression in the specimens with deep infiltration (T3 and T4) was higher than that in the specimens with superficial infiltration (T1 and T2) (81.1% vs. 53.3%, P<0.05). The positive rate of 5-LOX expression in TNM stage III and IIII cancer was higher than that in stage I and II (79.5% vs. 53.8%, P<0.05). The positive rate of 5-LOX expression in cancers of poor differentiation and non-differentiation adenocarcinoma was higher than that of well and moderately differentiated cancer (100% vs. 50.0%, P<0.05). There were no significant differences of 5-LOX expression with tumor size,vascular invasion and peritoneal dissemination.

CONCLUSION5-LOX expression in colorectal carcinoma is closely associated with lymph node metastasis, infiltration depth, differentiation degree and TNM stage.

Adult ; Aged ; Aged, 80 and over ; Arachidonate 5-Lipoxygenase ; metabolism ; Colorectal Neoplasms ; enzymology ; pathology ; Female ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Staging

OBJECTIVETo determine 5-lipoxygenase (5-LOX) expression and the effect of zileuton, a selective 5-LOX inhibitor,on hippocampal neuron injury induced by global cerebral ischemia in rats.

METHODSGlobal cerebral ischemia was induced by bilateral common carotid artery occlusion combined with hypotension in rats. 5-LOX expression was detected by Western blot analyses and 5-LOX localization was visualized by immunohistochemistry and double immunofluorescence methods. The 5-LOX inhibitor zileuton (10, 30, 50 mg/kg) was orally administered for 3 d after ischemia.

RESULTSThe 5-LOX expression was increased in the ischemic hippocampus on d1-7 (peaked at d3), and 5-LOX protein was primarily localized in neurons and translocated to the nuclei in the hippocampal CA1 region after ischemia. The 5-LOX inhibitor zileuton (30, 50 mg/kg) reduced ischemia-induced hippocampal neurons death 3d after ischemia.

CONCLUSION5-LOX is involved in global cerebral ischemic damage in rats, and the 5-LOX inhibitor zileuton has a protective effect on neuronal damage in the rat hippocampus following global cerebral ischemia.

Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; physiology ; Brain Ischemia ; metabolism ; pathology ; CA1 Region, Hippocampal ; metabolism ; pathology ; Disease Models, Animal ; Hydroxyurea ; analogs & derivatives ; pharmacology ; Lipoxygenase Inhibitors ; pharmacology ; Male ; Neurons ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo evaluate the translocation of 5-lipoxygenase (5-LOX)) after injuries by transfection with green fluorescence protein (GFP)/5-LOX in PC12 cells.

METHODSPC12 cells were stably transfected with pEGFP-C2/5-LOX (GFP/5-LOX) or pEGFP-C2 vectors (control). After treatment with oxygen-glucose deprivation (OGD), H(2)O(2) or NMDA, GFP/5-LOX localization in the cells was observed under a fluorescence microscope. Wild-type 5-LOX was determined by immunostaining after the treatment.

RESULTIn the GFP/5-LOX-transfected cells, GFP/5-LOX was primarily localized in the nucleus; while in the GFP-transfected cells, GFP was localized in both the cytoplasm and nucleus. After OGD and H(2)O(2) treatments, GFP/5-LOX was translocated to the nuclear membrane in 50.6 % and 57.7% cells respectively. However, after NMDA treatment or in GFP-transfected cells, no translocation was observed. Wild-type 5-LOX was distributed in the nuclei and cytoplasm, and all the 3 treatments induced 5-LOX translocation to the nuclear membrane.

CONCLUSIONIn the PC12 cells stably transfected with GFP/5-LOX, GFP/5-LOX is primarily distributed in the nuclei; the OGD-, H(2)O(2)- and NMDA-induced 5-LOX translocation exhibits different properties.

Animals ; Arachidonate 5-Lipoxygenase ; genetics ; metabolism ; Cell Nucleus ; metabolism ; Glucose ; pharmacology ; Green Fluorescent Proteins ; genetics ; metabolism ; Hydrogen Peroxide ; pharmacology ; Microscopy, Fluorescence ; N-Methylaspartate ; pharmacology ; Nuclear Envelope ; metabolism ; PC12 Cells ; Protein Transport ; drug effects ; Rats ; Recombinant Fusion Proteins ; genetics ; metabolism ; Transfection

OBJECTIVETo explore the protective mechanisms of sevoflurane against acute lung injury (ALI) induced by one-lung ventilation (OLV) in view of cyclooxygenase-2 (COX2) and 5-lipoxygenase (5-LOX) pathways.

METHODEighteen healthy Japanese white rabbits were randomized into sham-operated group (S group), OLV group (O group) and OLV + sevoflurane group (OS group). COX2 and 5-LOX protein and mRNA expressions in the lungs were detected by Western blotting and real-time PCR, respectively. Prostaglandin I2 (PGI2), thromboxane A2 (TXA2) and leukotrienes B2 (LTB2) in the lung tissues were quantified with ELISA. Histological scores and lung wet/dry weight (W/D) ratios were determined for lung injury assessment.

RESULTSCOX2 and 5-LOX protein and mRNA expressions and the contents of LTB2, TXA2 and PGI2 in the lungs, lung W/D ratio and histological scores were significantly higher while PGI2/TXA2 ratio was significantly lower in O group and OS group than in S group (P<0.05). Compared with those in O group, COX2 and 5-LOX expressions, pulmonary contents of LTB2, TXA2 and PGI2, and lung W/D ratio all decreased significantly but PGI2/TXA2 ratio was significantly elevated in OS group (P<0.05).

CONCLUSIONOLV may activate COX2 and 5-LOX pathways to result in increased production of arachidonic acid metabolites. Sevoflurane protects against OLV-induced ALI probably by reducing AA metabolites and regulating PGI2/TXA2 ratio through inhibitions of COX2 and 5-LOX pathways.

Acute Lung Injury ; etiology ; metabolism ; Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; Cyclooxygenase 2 ; metabolism ; Lung ; drug effects ; metabolism ; Methyl Ethers ; adverse effects ; One-Lung Ventilation ; adverse effects ; RNA, Messenger ; genetics ; Rabbits

OBJECTIVE: To elucidate the action mechanism of Xingnaojing Injection (, XNJI) for sepsis, and to target screen the potential bioactive ingredients. METHODS: An integrated protocol that combines in silico target screen (molecular docking) and database mapping was employed to find the potential inhibitors from XNJI for the sepsis-related targets and to establish the compound-target (C-T) interaction network. The XNJI's bioactive components database was investigated and the sepsis-associated targets were comprehensively constructed; the 3D structure of adenosine receptor A2a and 5-lipoxygenase proteins were established and evaluated with homology modeling method; system network pharmacology for sepsis treatment was studied between the bioactive ingredients and the sepsis targets using computational biology methods to distinguish inhibitors from non inhibitors for the selected sepsis-related targets and C-T network construction. RESULTS: Multiple bioactive compounds in the XNJI were found to interact with multiple sepsis targets. The 32 bioactive ingredients were generated from XNJI in pharmacological system, and 21 potential targets were predicted to the sepsis disease; the biological activities for some potential inhibitors had been experimentally confirmed, highlighting the reliability of in silico target screen. Further integrated C-T network showed that these bioactive components together probably display synergistic action for sepsis treatment. CONCLUSIONS The uncovered mechanism may offer a superior insight for understanding the theory of the Chinese herbal medicine for combating sepsis. Moreover, the potential inhibitors for the sepsis-related targets may provide a good source to find new lead compounds against sepsis disease.
Arachidonate 5-Lipoxygenase ; metabolism ; Computer Simulation ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; therapeutic use ; Humans ; Injections ; Phytochemicals ; therapeutic use ; Receptor, Adenosine A2A ; metabolism ; Reproducibility of Results ; Sepsis ; drug therapy ; metabolism