Tanihiro Yoshimoto

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Arachidonate 12-lipoxygenase introduces a molecular oxygen at carbon 12 of arachidonic acid to generate a 12-hydroperoxy derivative. The enzymes generate 12-hydroperoxy derivatives with either S- or R-configurations. There are three isoforms of 12S-lipoxygenases named after the cells where they were first identified; platelet, leukocyte and epidermis. The(More)
To study a putative paracellular protective mechanism of astrocytes for neurons, immunohistochemical analysis was performed in ischemic rat brain, which colocalized with the expression of heme oxygase-1 (HO- 1) in astroglias surrounding dying TUNEL-positive neurons. As an in vitro paradigm for ischemia, cultured astrocytes were exposed to normobaric hypoxia(More)
12/15-lipoxygenase (12/15-LO) enzyme and products have been associated with inflammation and atherosclerosis. However, the mechanism of effects of the 12/15-LO products has not been fully clarified. To study the role of 12/15-LO in cytokine expression, experiments with direct additions of the12/15-LO products, 12(S)-hydroxyeicosa tetraenoic acid or(More)
Age-dependent increase of peroxidation of membrane fatty acids such as arachidonic acid (ARA) and docosahexaenoic acid (DHA) in neurons was reported to cause a decline of the hippocampal long-term potentiation (LTP) and cognitive dysfunction in rodents. Although supplementation of ARA and DHA can improve LTP and cognitive function in rodents, their effects(More)
Enhanced endoplasmic reticulum (ER) stress has been implicated in various pathological situations including inflammation. During a search for compounds that regulate ER stress, we identified vaticanol B, a tetramer of resveratrol, as an agent that protects against ER stress-induced cell death. Vaticanol B suppressed the induction of unfolded protein(More)
Intracellular glutathione (GSH) depletion induced by buthionine sulfoximine (BSO) caused cell death that seemed to be apoptosis in C6 rat glioma cells. Arachidonic acid (AA) promoted BSO-induced cell death by accumulating reactive oxygen species (ROS) or hydroperoxides. AA inhibited caspase-3 activation and internucleosomal DNA fragmentation during the(More)
Giant DNA fragments (1-2 Mbp) were found in C6 rat glioma cells irradiated by a lethal dose of ultraviolet-C (UV-C, 254 nm) at 50 J/m(2). After irradiation, the fragments mutated into high-molecular-weight (100-800 kbp) DNA fragments and then into ladder-formed internucleosomal DNA fragments. Poly-ADP-ribose polymerase (PARP) activity and NAD levels were(More)
Accumulating evidence suggests that platelet-type 12-lipoxygenase (p12-LOX) plays an important role in tumor development. However, how p12-LOX contributes to tumorigenesis is still not understood. The role of p12-LOX was therefore examined in tumor promotion using mouse epidermal JB6 P+ cells that are sensitive to(More)
Oxidative modification of low-density lipoprotein (LDL) is one of the critical steps for the development of atherosclerosis. Accumulating studies have indicated that 12/15-lipoxygenase highly expressed in macrophages plays an essential role in the oxidation of circulating LDL. It has been demonstrated that LDL needs to bind the LDL receptor-related protein(More)
Oxidation of low density lipoprotein (LDL) is the key step for the development of atherosclerosis. The 12/15-lipoxygenase expressed in macrophages is capable of oxygenating linoleic acid esterified to cholesterol in the LDL particle, and thus this enzyme is presumed to initiate LDL oxidation. We recently reported that LDL receptor-related protein (LRP) was(More)