Pathogenic mutations in the ALS gene CCNF cause cytoplasmic mislocalization of Cyclin F and elevated VCP ATPase activity.

Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron disease characterized by a progressive decline in motor function. Genetic analyses have identified several genes mutated in ALS patients, and one of them is Cyclin F gene (CCNF), the product of which (Cyclin F) serves as the substrate-binding module of a SKP1-CUL1-F-box protein (SCF) ubiquitin ligase complex. However, the role of Cyclin F in ALS pathogenesis has remained unclear. Here, we show that Cyclin F binds to valosin-containing protein (VCP), which is also reported to be mutated in ALS, and that the two proteins colocalize in the nucleus. VCP was found to bind to the NH2-terminal region of Cyclin F and was not ubiquitylated by SCFCyclin F in transfected cells. Instead, the ATPase activity of VCP was enhanced by Cyclin F in vitro. Furthermore, whereas ALS-associated mutations of CCNF did not affect the stability of Cyclin F or disrupt formation of the SCFCyclin F complex, amino acid substitutions in the VCP binding region increased the binding ability of Cyclin F to VCP and activity of VCP as well as mislocalization of the protein in the cytoplasm. We also provided evidence that the ATPase activity of VCP promotes cytoplasmic aggregation of transactivation responsive region (TAR) DNA-binding protein 43, which is commonly observed in degenerating neurons in ALS patients. Given that mutations of VCP identified in ALS patients also increase its ATPase activity, our results suggest that Cyclin F mutations may contribute to ALS pathogenesis by increasing the ATPase activity of VCP in the cytoplasm, which in turn increases TDP-43 aggregates.

Quantification of the Flavor and Taste of Gonads from the Sea Urchin Mesocentrotus nudus Using GC-MS and a Taste-Sensing System.

Sea urchin gonads are a delicious seafood item of high commercial value. Our past studies have revealed that the gonads of the sea urchin Mesocentrotus nudus fed the basal frond portion of fresh Saccharina kelp (BS) or the sporophylls of fresh Undaria (SU) during May-July are of high-quality. The present study investigated the flavor and taste of BS and SU gonads in comparison with those from non-fed M. nudus (NF) using gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC)-sniffing techniques, and a taste-sensing system. Data of the estimated intensity of taste (EIT) were compared with assessment of gonads from M. nudus collected from an Eisenia bed (fishing ground) and a barren in July. Gonads from both BS and SU released pleasant green, sour, and fruity aromas characteristic of butyl acetate, which are here recognized essential flavor components of high-quality gonads. The gonads of BS and SU had a strong umami taste compared to those of NF, and the Eisenia bed and the barren. The most marketable M. nudus gonads were assessed to be those with green and fruity aromas from butyl acetate, sweet aroma from benzaldehyde, umami EIT > 13.8, bitterness EIT < 3.1, and without any unpleasant sulfurous odor from sulfur-containing compounds.

Induction of a 5-lipoxygenase product by daidzein is involved in the regulation of influenza virus replication.

This study was conducted to evaluate the regulation mechanism of influenza virus replication following treatment of Madin-Darby canine kidney cells with the soy isoflavone daidzein. We performed comparative qualitative and quantitative analyses of lipid peroxide between mock-infected and virus-infected cells treated with or without daidzein, as it had been reported that daidzein was an antioxidant and lipid peroxide levels increased upon virus infection. Contrary to our belief, lipid peroxides were not elevated in virus-infected cells and no decrease in lipid peroxides was observed in daidzein-treated cells. In daidzein-treated cells, 5-hydroxyeicosatetraenoic acid, the 5-lipoxygenase product derived from arachidonate, was significantly elevated compared to other lipid peroxides. Zileuton (5-lipoxygenase inhibitor) and 5-lipoxygenase knockdown reduced the daidzein-induced antiviral effect. Moreover, virus replication was regulated by treatment with 5-hydroperoxyeicosatetraenoic acid, a precursor of 5-hydroxyeicosatetraenoic acid and 5-lipoxygenase primary product. These results suggest that daidzein regulates virus replication via signal transduction through 5-lipoxygenase products.

Biobank Establishment and Sample Management in the Tohoku Medical Megabank Project.

The Tohoku Medical Megabank biobank (TMM biobank) is the first major population-based biobank established in Japan. The TMM biobank was established based on two population cohorts and is a reconstruction program from the Great East Japan Earthquake and Tsunami of 2011. The biobank stores more than 3.4 million tubes of biospecimens and associated health and analytic data obtained from approximately 150,000 TMM cohort participants between May 2013 and December 2018, and the TMM biobank currently shares high-quality specimens and data. Various biospecimens, including peripheral and cord blood mononuclear cells, buffy coat, plasma, serum, urine, breast milk and saliva have been collected in the TMM biobank. To minimize human error and maintain the quality of data and specimens, we have been utilizing laboratory information management system into various biobank procedures from registration to storage with various automation systems, such as liquid dispensing, DNA extraction and their storage. The biobank procedures for the quality management system (ISO 9001:2015) and information security management system (ISO 27001:2013) are certified by the International Organization for Standardization. The quality of our biobank samples fulfills the pre-analytical requirements for researchers conducting next-generation whole genome sequencing, DNA array analyses, proteomics, metabolomics, etc. We established analytical centers to conduct standard genomic and multiomic analyses in-house and share the generated data. Additionally, we generate thousands of Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines and proliferating T cells for functional studies. The TMM biobank serves as an indispensable infrastructure for academic, clinical and industrial research to actualize next-generation medicine in Japan.

Probucol induces the generation of lipid peroxidation products in erythrocytes and plasma of male cynomolgus macaques.

We previously reported that probucol, a lipid lowering agent, protected mice from malaria infection via depletion in plasma α-tocopherol. The antioxidant α-tocopherol in host circulation is necessary for the malaria parasites to protect themselves from oxidative stress in erythrocytes where high amounts of reactive oxygen species are generated. To assess the potential for the clinical application of probucol as an anti-malarial therapy, it was necessary to determine the effects of probucol by using primate experiments. Here we verified that probucol induces an α-tocopherol decrement in cynomolgus macaque erythrocytes and plasma. After 2 weeks of probucol administration at doses of 200 or 400 mg/kg/day, the α-tocopherol contents in erythrocytes tended to decrease. The contents of hydroxyoctadecadienoic acids and 7ß-hydroxycholesterol, peroxidation products derived from linoleic acid and cholesterol, respectively, increased in erythrocytes. On the other hand, plasma α-tocopherol concentration showed a marginal decrement. Plasma lipid peroxidation products were transiently increased in the early stages of probucol administration. No adverse effects were observed throughout the experiment, although the dosage of probucol was higher than the clinical maximum dosage. Considering that malaria proliferates in erythrocytes, probucol-induced disruption of redox homeostasis in erythrocytes could be effective in the inhibition of parasite proliferation.

Probucol dramatically enhances dihydroartemisinin effect in murine malaria.

BACKGROUND: Artemisinin-based combination therapy (ACT) has been adopted as national policy for the first-line treatment in large number of malaria-endemic regions. However, artemisinin-resistant parasites have emerged and are spreading, with slow-cleaning parasites being reported in patients treated with ACT. It means that more parasites are exposed to the partner drug alone and the risk of developing resistant parasites against the partner drug is increasing. Therefore, the development of a new method to enhance the effect of artemisinin is required. In this study, the potential effect of probucol as a combination drug of dihydroartemisinin (DHA), an artemisinin derivative, was examined. METHODS: C57BL/6 J mice infected with Plasmodium yoelii XL-17 were treated with probucol and/or DHA. The mice were fed with a probucol mixed diet from 2 weeks before infection and through infection period. DHA was injected to mice three to 5 days post infection once a day. In addition, 0.5 % (w/w) probucol was mixed with vitamin E supplemented diet (800 mg/kg) and fed to mice infected with P. yoelii XL-17 to examine the mechanisms of probucol on murine malaria. Furthermore, 8-OHdG, a biomarker of oxidized DNA, was detected in infected red blood cells (iRBC) taken from infected mice by immunofluorescent staining. RESULTS: With dose-dependent manner, both probucol and DHA decreased parasitaemia and increased survival rate of mice infected with P. yoelii XL-17. A significantly larger amount of 8-OHdG was detected in iRBC taking from probucol-treated mice than control mice. In addition, a large amount of vitamin E supplementation eliminated the effect of probucol against P. yoelii XL-17 infection and lowered the effect of probucol on host plasma vitamin E concentration. The effective doses for probucol and DHA were 0.5 % and 30 mg/kg, respectively, in each single treatment. While the combination treatment of 0.25 % probucol and 7.5 mg/kg DHA was effective in all mice from P. yoelii XL-17 infection. CONCLUSION: This study demonstrated that probucol has some impact on malaria by oxidative stress through the induction of host plasma vitamin E deficiency. Moreover, the effective dose of DHA on malaria was decreased by prophylactic treatment of probucol. This finding indicates that probucol might be a candidate for a prophylactic treatment drug to enhance the effect of DHA.

Dynamics of hydroxyoctadecadienoic acid in epilepsy patients treated with valproic acid.

BACKGROUND: The effects of valproic acid (VPA) on oxidative stress are controversial due to differences in experimental conditions. Recently, total hydroxyoctadecadienoic acid (tHODE), derived from linoleic acid, was proposed as a potent biomarker to evaluate oxidative stress. METHODS: The subjects consisted of 10 new-onset epilepsy patients treated with VPA. We measured plasma tHODE consecutively for 1 year to evaluate the degree of oxidative stress and then compared plasma tHODE at the beginning and the end of experiments with the peak level. Ten age-matched healthy subjects were recruited as a control group and their plasma tHODE was compared to the initial plasma tHODE of the epilepsy group. Measurements were done using liquid chromatography-tandem mass spectrometry. RESULTS: Mean initial plasma tHODE in the epilepsy group was 165.2 ± 76.8 nmol/L, which was not significantly different from that of the control group (199.3 ± 62.5 nmol/L). In five epilepsy patients, plasma tHODE increased above the pathological level in 6 months, but returned to normal within 1 year. In the whole group, the difference plasma tHODE between peak, at the beginning and 1 year later, was significant. CONCLUSION: Oxidative stress generated by VPA increased temporarily, but decreased to normal after 1 year. it is reasonable to be concerned about the effects of oxidative stress, especially at the start of VPA treatment.

Effect of anti-hyperlipidemia drugs on the alpha-tocopherol concentration and their potential for murine malaria infection.

The current preventions of malaria are protection against mosquito bites and taking chemoprophylactic anti-malarial drugs. However, drug therapies are usually associated with adverse events and emergency of drug-resistant malaria parasites. Previous study showed that host plasma alpha-tocopherol deficiency enhanced resistance against malaria infection in mice. Here, we report a new prevention strategy against malaria by using anti-hyperlipidemia drugs, ezetimibe, berberine, cholestyramine, and probucol to modify the host plasma alpha-tocopherol concentration. The drugs were mixed with diet and fed to C57BL/6J mice for 2 weeks. Although all drugs reduced plasma alpha-tocopherol concentration after 2 weeks of feeding, probucol-treated mice showed 90 % reduction and it was the lowest alpha-tocopherol concentration among the four drugs. Ezetimibe, berberine, and combination of ezetimibe and berberine pretreatment for 2 weeks were not effective against infection of Plasmodium yoelii XL17, a lethal strain, for survival and parasitemia in mice. Two-week pretreatment and 1-week treatment after infection of cholestyramine had also no effect on malaria infection. Survival rates of cholestyramine, ezetimibe, and/or berberine treated mice were 0-22 %. However, probucol caused significant decrease in parasitemia and increased in mice survival following 2-week pretreatment and 1-week treatment after infection. All control mice died while all probucol treated mice survived during the course of infection. Thus, probucol which reduced plasma alpha-tocopherol concentration was effective in enhancing the host to resist malaria infection in mice. Our finding indicates that plasma alpha-tocopherol reducing drugs like probucol might be a candidate for beneficial prevention strategy for travelers from malaria-free area.

The induction of lipid peroxidation during the acute oxidative stress response induced by intratracheal instillation of fine crystalline silica particles in rats.

Crystalline silica (SiO2) is an important material for industry but is considered potentially carcinogenic. Inhalation of a crystalline SiO2 aerosol may contribute to serious lung diseases. Crystalline SiO2 particles are commonly used as a positive control in toxicity assays of particulate materials (e.g. nanoparticles). Crystalline SiO2 induces oxidative stress resulting in lipid peroxidation, but the acute oxidative stress response in the lung is not well understood. Lipid peroxidation during the acute stage of oxidative stress after instillation of crystalline SiO2 into rats was examined by bronchoalveolar lavage fluid (BALF) analysis. The levels of 8-iso-prostaglandin F2α and hydroxyoctadecadienoic acid (HODE) in the BALF were measured using liquid chromatography coupled to quadrupole mass spectrometry. The concentration of the antioxidant protein heme oxygenase-1 (HO-1) in the BALF was determined using enzyme-linked immunosorbent assay. Intratracheal instillation of crystalline SiO2 increased the level of HODE and HO-1 in BALF at 24 h after administration. The levels of HODE and HO-1 returned to baseline at 72 h after instillation. Lactate dehydrogenase leakage was observed only after 1 h instillation. These results suggest that the contribution of oxidative stress to the pulmonary toxicity of crystalline SiO2 is minimal in the early acute stage after exposure.

Enhancement of lipid peroxidation and its amelioration by vitamin E in a subject with mutations in the SBP2 gene.

Selenocysteine (Sec) insertion sequence-binding protein 2 (SBP2) is essential for the biosynthesis of Sec-containing proteins, termed selenoproteins. Subjects with mutations in the SBP2 gene have decreased levels of several selenoproteins, resulting in a complex phenotype. Selenoproteins play a significant role in antioxidative defense, and deficiencies in these proteins can lead to increased oxidative stress. However, lipid peroxidation and the effects of antioxidants in subjects with SBP2 gene mutations have not been studied. In the present study, we evaluated the lipid peroxidation products in the blood of a subject (the proband) with mutations in the SBP2 gene. We found that the proband had higher levels of free radical-mediated lipid peroxidation products, such as 7ß-hydroxycholesterol, than the control subjects. Treatment of the proband with vitamin E (α-tocopherol acetate, 100 mg/day), a lipid-soluble antioxidant, for 2 years reduced lipid peroxidation product levels to those of control subjects. Withdrawal of vitamin E treatment for 7 months resulted in an increase in lipid peroxidation products. Collectively, these results clearly indicate that free radical-mediated oxidative stress is increased in the subject with SBP2 gene mutations and that vitamin E treatment effectively inhibits the generation of lipid peroxidation products.

Type 2 diabetes model TSOD mouse is exposed to oxidative stress at young age.

Tsumura Suzuki Obese Diabetes (TSOD) mouse, a model of obese type 2 diabetes, older than around 11 weeks of age develops diabetic phenotypes. Previous studies have indicated that the development of diabetes is partly due to three loci associated with body weight and glucose homeostasis. However, little is known about the initial events triggering the development of the diabetic phenotypes in TSOD mouse. Here, we investigated the alteration of diabetes-related parameters, including the levels of blood glucose and inflammatory cytokines, and the oxidative stress status, in young TSOD mice. TSOD mice at 5 weeks of age showed increases in body weight and plasma total cholesterol level, but not hyperglycemia or impaired glucose tolerance, compared with age-matched control Tsumura Suzuki Non-Obese (TSNO) mice. Plasma tumor necrosis factor (TNF)-α and interleukin (IL)-6 were not detected in TSOD mice at 5 weeks of age. However, plasma total hydroxyoctadecadienoic acid (tHODE), a biomarker of oxidative stress, was increased in TSOD mice relative to TSNO mice at same age. The results demonstrated that young TSOD mice are exposed to oxidative stress before developing the diabetic phenotypes, and suggested that oxidative stress is an initial event triggering the development of diabetes in TSOD mice.

DHA concentration of red blood cells is inversely associated with markers of lipid peroxidation in men taking DHA supplement.

An increase in the proportion of fatty acids with higher numbers of double bonds is believed to increase lipid peroxidation, which augments the risk for many chronic diseases. (n-3) Polyunsaturated fatty acids provide various health benefits, but there is a concern that they might increase lipid peroxidation. We examined the effects of docosahexaenoic acid [22:6 (n-3)] supplementation on lipid peroxidation markers in plasma and red blood cells (RBC) and their associations with red blood cell and plasma fatty acids. Hypertriglyceridemic men (n = 17 per group) aged 39-66 years participated in a double-blind, randomized, placebo-controlled, parallel study. They received no supplements for the first 8 days and then received 7.5 g/day docosahexaenoic acid oil (3 g/day docosahexaenoic acid) or olive oil (placebo) for 90 days. Fasting blood samples were collected 0, 45, and 91 days after supplementation. Docosahexaenoic acid supplementation did not change plasma or RBC concentrations of lipid peroxidation markers (total hydroxyoctadecadienoic acid, total hydroxyeicosatetraenoic acid, total 8-isoprostaglandin F2α, 7α-hydroxycholesterol, 7ß-hydroxycholesterol) when pre- and post-supplement values were compared. However, the post-supplement docosahexaenoic acid (DHA) concentration was inversely associated with RBC concentrations of ZE-HODE, EE-HODE, t-HODE, and total 8-isoprostaglandin F2α, (p<0.05). RBC concentration of hydroxycholesterol was also inversely associated with DHA but it did not attain significance (p = 0.07). Our results suggest that increased concentration of DHA in RBC lipids reduced lipid peroxidation. This may be another health benefit of DHA in addition to its many other health promoting effects.

Whole blood transcriptome analysis for age- and gender-specific gene expression profiling in Japanese individuals.

Whole blood transcriptome analysis is a valuable approachin medical research, primarily due to the ease of sample collection and the richness of the information obtained. Since the expression profile of individual genes in the analysis is influenced by medical traits and demographic attributes such as age and gender, there has been a growing demand for a comprehensive database for blood transcriptome analysis. Here, we performed whole blood RNA sequencing (RNA-seq) analysis on 576 participants stratified by age (20-30s and 60-70s) and gender from cohorts of the Tohoku Medical Megabank (TMM). A part of female segment included pregnant women. We did not exclude the globin gene family in our RNA-seq study, which enabled us to identify instances of hereditary persistence of fetal hemoglobin based on the HBG1 and HBG2 expression information. Comparing stratified populations allowed us to identify groups of genes associated with age-related changes and gender differences. We also found that the immune response status, particularly measured by neutrophil-to-lymphocyte ratio (NLR), strongly influences the diversity of individual gene expression profiles in whole blood transcriptome analysis. This stratification has resulted in a data set that will be highly beneficial for future whole blood transcriptome analysis in the Japanese population.

Detection and Correction of Sample Misidentifications in a Biobank Using the MassARRAY System and Genomic Information.

With the number of samples increasing in many biobanks, one of the most pressing tasks is recording the correct relationships between information and the specimens. Genomic information is useful in determining the identity of these specimens. The Tohoku Medical Megabank Organization is running one of the largest biobanks in Japan. Here, we introduce a management system, which includes the development of a new probe set for the MassARRAY system for use during the production of proliferating T cells (T cells) and lymphoblastoid cell lines (LCLs). We selected single nucleotide variants that could be detected by next-generation sequencing and showed high resolution with ∼0.5 minor allele frequencies. After checking the set of probes against 96 samples from 48 people, we obtained no contradictory results in comparison with our genome sequence information. When we applied the set to our 3035 LCLs and 2256 T cells, the result showed 98.93% consistency with the corresponding genomic information. We surveyed the handling records of the 1.07% of samples that showed inconsistencies, and found that most had resulted from human errors (ID swapping between samples) during manual operations. After improving a few error-prone protocols, the error rate dropped to 0.47% for LCLs and 0% for T cells. Overall, the system that we developed shows high accuracy with easy and fast operability, and provides a good opportunity to improve the validation procedure to facilitate high-quality banking, especially in cases involving genomic information.

Construction of a trio-based structural variation panel utilizing activated T lymphocytes and long-read sequencing technology.

Long-read sequencing technology enable better characterization of structural variants (SVs). To adapt the technology to population-scale analyses, one critical issue is to obtain sufficient amount of high-molecular-weight genomic DNA. Here, we propose utilizing activated T lymphocytes, which can be established efficiently in a biobank to stably supply high-grade genomic DNA sufficiently. We conducted nanopore sequencing of 333 individuals constituting 111 trios with high-coverage long-read sequencing data (depth 22.2x, N50 of 25.8 kb) and identified 74,201 SVs. Our trio-based analysis revealed that more than 95% of the SVs were concordant with Mendelian inheritance. We also identified SVs associated with clinical phenotypes, all of which appear to be stably transmitted from parents to offspring. Our data provide a catalog of SVs in the general Japanese population, and the applied approach using the activated T-lymphocyte resource will contribute to biobank-based human genetic studies focusing on SVs at the population scale.

Cytoplasmic ubiquitin ligase KPC regulates proteolysis of p27(Kip1) at G1 phase.

The cyclin-dependent kinase inhibitor p27(Kip1) is degraded at the G0-G1 transition of the cell cycle by the ubiquitin-proteasome pathway. Although the nuclear ubiquitin ligase (E3) SCF(Skp2) is implicated in p27(Kip1) degradation, proteolysis of p27(Kip1) at the G0-G1 transition proceeds normally in Skp2(-/-) cells. Moreover, p27(Kip1) is exported from the nucleus to the cytoplasm at G0-G1 (refs 9-11). These data suggest the existence of a Skp2-independent pathway for the degradation of p27(Kip1) at G1 phase. We now describe a previously unidentified E3 complex: KPC (Kip1 ubiquitination-promoting complex), consisting of KPC1 and KPC2. KPC1 contains a RING-finger domain, and KPC2 contains a ubiquitin-like domain and two ubiquitin-associated domains. KPC interacts with and ubiquitinates p27(Kip1) and is localized to the cytoplasm. Overexpression of KPC promoted the degradation of p27(Kip1), whereas a dominant-negative mutant of KPC1 delayed p27(Kip1) degradation. The nuclear export of p27(Kip1) by CRM1 seems to be necessary for KPC-mediated proteolysis. Depletion of KPC1 by RNA interference also inhibited p27(Kip1) degradation. KPC thus probably controls degradation of p27(Kip1) in G1 phase after export of the latter from the nucleus.

Localization of the invadopodia-related proteins actinin-1 and cortactin to matrix-contact-side cytoplasm of cancer cells in surgically resected lung adenocarcinomas.

OBJECTIVES: Actin-associated proteins at cell-matrix-contact sites form invadopodia in cancer cells and participate in migration, matrix degradation and invasion. We investigated an alteration of subcellular localization of invadopodia-related actin-associated proteins, actinin-1 and cortactin, in lung adenocarcinomas, its clinical significance, and its possible regulatory factors. METHODS: Invadopodia-related proteins, actinin-1 and cortactin, were immunohistochemically examined in 90 cases of lung adenocarcinomas. Expression of invadopodia-associated proteins and their possible regulators in lung adenocarcinomas were examined by real-time RT-PCR, database search, and immunohistochemistry. RESULTS: Actinin-1 and cortactin showed matrix-contact-side localization in adenocarcinoma cells, but rarely in normal bronchiolar epithelial cells, alveolar cells, or precursor lesion atypical adenomatous hyperplasia cells. Immunoelectron-microscopic examination of adenocarcinoma cells revealed actinin-1 localization to matrix-contact-side cytoplasm with cytoplasmic protrusions. Matrix-contact-side localization of actinin-1 and cortactin was correlated with tumor stages, lymph node metastasis, vascular permeation, and loss of basement membrane. The tumor-specific survival rate was worse for the group in which matrix-contact-side localization of cortactin was high than for the low group. mRNA of the Rho guanine exchange factor epithelial cell transforming sequence-2 (Ect2) tended to be overexpressed in lung adenocarcinomas and cytoplasmic expression of Ect2 tended to be correlated with matrix-contact-side localization of actinin-1. CONCLUSION: Matrix-contact-side localization of invadopodia-related proteins in the lung adenocarcinoma cells were correlated with invasion, metastasis, and poor prognosis. Ect2 was a possible regulator of matrix-contact-side localization of invadopodia-related proteins.

Stress-activated leukocyte 12/15-lipoxygenase metabolite enhances struggle behaviour and tocotrienols relieve stress-induced behaviour alteration.

Stress induces emotional arousal causing anxiety, irritability, exaggerated startle behaviour, and hypervigilance observed in patients with trauma and stress-related mental disorders, including acute stress disorder and post-traumatic stress disorder. Central norepinephrine release promotes stress-induced emotional arousal. However, the regulator of emotional arousal remains unknown. Here, we show that the arachidonate-derived metabolite produced by stress-activated leukocyte 12/15-lipoxygenase is remarkably elevated in the plasma and upregulates the central norepinephrine release, resulting in the enhancement of the struggle behaviour (= escape behaviour) in the tail suspension test. Struggle behaviour is mimicking a symptom of emotional arousal. This stress-induced struggle behaviour was absent in 12/15-lipoxygenase deficient mice; however, intravenous administration of a 12/15-lipoxygenase metabolite to these mice after stress exposure rekindled the struggle behaviour. Furthermore, tocotrienols and geranylgeraniol reduced stress-induced 12/15-lipoxygenase metabolite production and suppressed the struggle behaviour. Our findings indicate that arachidonate-derived 12/15-lipoxygenase metabolite is involved in the regulation of stress-enhanced central norepinephrine release and struggle behaviour. In addition, we propose 12/15-lipoxygenase as a potential therapeutic target for the treatment of emotional arousal observed in stress-related mental disorders.