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Inhibition of catecholamine metabolism reduces α-synuclein related cytotoxicity in PC12 cells
S234
Abstracts / Neuroscience Research 58S (2007) S1–S244
P3-h38 Preventive effects of phytoestrogens on the paraquatinduced toxicities in the cellular model of Parkison disease
P3-h41
Shin-ichi Kyuhou Department of Physiology, Kansai Medical University, Osaka, Japan
Hiroki Takeuchi 1 , Nobuhisa Aoyagi 1 , Kentaro Ymakawa 4 , Ryosuke Takahashi 1 , Shun Shimohama 2 , Akinori Akaike 3 , Hideyuki Sawada 4 , Yoshihisa Kitamura 5 , Takashi Taniguchi 5 1 Department of Neurology, Kyoto University, Kyoto, Japan; 2 Department of Neurology, Sapporo Medical University, Sapporo, Japan; 3 Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; 4 Clinical Research Center, Utano National Hospital, Kyoto, Japan; 5 Department of Neurobiology, Kyoto Pharmaceutical University, Kyoto, Japan
Epidemiological studies reported that paraquat, a hervicide, is one of the environmental risk factors of Parkinson disease. Paraquat induced apoptosis in PC12 cells. The endoplasmic reticulum (ER) stress was found to be involved in this paraquat -induced apoptosis because upregulation of CHOP and activation of Jun-N-terminal kinase (JNK), ER stress activated substrates, were observed. Upregulation of mRNA of BiP, an ER-specific chaperone, and splicing of the mRNA of the X box binding protein were observed, indicating the occurrence of the unfolded protein response (UPR). Prominent production of reactive oxygen species (ROS) was observed after paraquat exposure. Pre-incubation of phytoestrogens such as resveratrol prevalent in the red wine and genistein derived from soybean reduced the paraquat -induced ROS. Resvertrol reduced the UPR and increased the viability of PC12 cells was increased. In contrast, genistein was less effective to prevent the ER stress and the paraquat-induced cell death. Research fund: Grant from Fuji foundation for protein research.
P3-h39 Quantitative relationship of parkinsonian thalamic band activities with rigidity
Tomokazu Oshima, Yohsuke Narabayashi Narabayashi Memorial Laboratory of Neurology, Neurological Clinic, Tokyo, Japan Excess -band activities are observed in parkinsonian thalamic ventrolateral nucleus (VL). We examined how these activities were related with rigidity alleviated after the thalamotomy. Rigidity on the UPDRS and postoperative reduction (dR) were estimated in 100 patients with PD and 9 patients with essential tremor divided into six groups of rigidity preoperatively scored 0 (N), 0.5 (Ia), 1 (Ib), 2 (II), 3 (III), and 4 (IV). Filtered -band local field potentials (-waves) were quantified by the mean time integral (m) of 13–27 Hz wavelets in percent of 3-sec sample records. After the surgery, rigidity disappeared in groups Ia, Ib, and II, and remained partially in III or heavily in IV. The VL m was progressively increased through N, Ia, Ib to II, and decreased in III to IV. The m-to-dR relationship was positive, but non-linear of histeresis nature. The histeresis may arise by the time lag from the pathology represented by -waves to the expression of rigidity. The VL m represented only a part of severe rigidity, indicating that the late pathology involved other sites beyond the VL.
P3-h4Ø Neurosin cleaves the NAC region of ␣-synuclein
Takashi Kasai 1 , Takashi Kasai 1 , Takahiko Tokuda 1 , Toshiki Mizuno 1 , Masanori Nakagawa 1 , Yoshihisa Watanabe 1 , Nozomi Yamaguchi 1 , Fuyuki Kametani 2 1 Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan; 2 Tokyo Institute of Psychiatry, Tokyo, Japan Background: Neurosin is one of serine proteases predominantly expressed in a central nervous system. Neurosin is presumed to play an important role in metabolism of ␣-synuclein (␣-syn), because the previous report showed that neurosin exists in Lewy bodies and degrades ␣-syn in vitro. However the details of ␣-syn degradation by neurosin are little known. Method: Neurosin-mediated cleaving sites were investigated by LC/MS/MS. Degradations of wild and mutant ␣-syn by neurosin were evaluated by SDS-PAGE. Findings: The dominant cleavage site was between Lys80 and Thr81. Neurosin digested A30P mutant ␣-syn less efficiently than the wild type one. Interpretation: The dominant cleavage site we determined is the center of the NAC region, which is responsible for polymerization of the ␣-syn. This result suggests a hyothesis that neurosin inhibits the polymerization of ␣-syn by cleaving it in the NAC region.
Nicotinic receptor stimulation is protective for dopaminergic neuron
Nicotine could play a protective role for dopaminergic neuron, but its mechanism is still unclear. We demonstrated that nicotine prevented rotenone-induced dopaminergic cell death in primary cultures of rat ventral mesencephalon. The neuroprotection was inhibited by nicotinic acetylcholine rececptor (nAChR) antagonists, PI3 kinase inhibitor, and we uncovered elebvated pAkt/PKB by stimulating nAChRs, thus nicotine showed antiapoptotic effect via PI3 kinase-Akt/PKB pathway.Also we showed nicotine improved behavior and nigral dopaminergic cell loss of chronic rotenone-treated parkinsonian model mice (n = 8–12 per group). Stimulation of nAChRs may be useful as a treatment for Parkinson disease.
P3-h44 MPTP neurotoxicity is enhanced by a restraint stress in C57BL/6 mice
Daisuke Wada 1,2 , Atsushi Mori 1 , Satoru Nakai 1 , Naoki Kurihara 1 , Satoshi Ohashi 1 , Mitsuo Oshimura 2 , Masami Nakai 1 1 Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan; 2 Tottori University, Yonago, Japan
Although the pathogenesis of idiopathic Parkinson’s disease (PD) is not fully understood, a number of environmental factors as well as genetic ones are thought to contribute to the demise of dopaminergic neurons of nigrostriatal pathway. The neurotoxin 1-methyl-4-phenyl1,2,3,6-tetrahydropyridine (MPTP) has been used to create an animal model of PD in nonhuman primates and mice. This study investigated the effect of a various kinds of stress, one of the environmental factors, on dopaminergic neurodegeneration induced by MPTP intoxication. C57BL/6 mice were treated with single injection of MPTP (20 mg/kg, i.p.) and immediately exposed to stress for 2 h. We found that an exposure to restraint stress in MPTP-treated mice caused a severer loss of striatal nerve terminals as indicated by decreases in dopamine transporter protein levels as well as dopamine levels as compared with MPTP (alone)treated mice. This result suggests that restraint stress might promote the dopaminergic neurodegeneration in MPTP-treated mice.
P3-h45 Inhibition of catecholamine metabolism reduces ␣-synuclein related cytotoxicity in PC12 cells Satoru Ito Department of Neurology, Tottori University, Tottori, Japan
An intermediate polymer of quinone-binding ␣-synuclein (␣-syn) has been reported to show cytotoxicity in the pathogenesis of Parkinson’s disease. However, its detailed mechanism of action is still not well understood. We established PC12 cell lines that overexpress ␣-syn in a tetracyclineinducible manner and then examined their vulnerability against various stressors (MPP+ , Tunicamycin, Etoposide). An increased number of apoptotic cells (205%, 179%, 232%, respectively) were observed in the cells that overexpressed ␣-syn in comparison to cells not expressing ␣-syn. In addition, ␣-methyl-tyrosine, a specific inhibitor of tyrosine hydroxylase, reduced the number of apoptotic cells (26.3%, 49.6%, 62.5% reduction). Catecholamine is thus suggested to enhance cytotoxicity under various stressors such as ER stress, mitochondrial toxicity, genotoxic stress in cells demonstrating an overexpression of ␣-syn.
Abstracts / Neuroscience Research 58S (2007) S1–S244
P3-h38 Preventive effects of phytoestrogens on the paraquatinduced toxicities in the cellular model of Parkison disease
P3-h41
Shin-ichi Kyuhou Department of Physiology, Kansai Medical University, Osaka, Japan
Hiroki Takeuchi 1 , Nobuhisa Aoyagi 1 , Kentaro Ymakawa 4 , Ryosuke Takahashi 1 , Shun Shimohama 2 , Akinori Akaike 3 , Hideyuki Sawada 4 , Yoshihisa Kitamura 5 , Takashi Taniguchi 5 1 Department of Neurology, Kyoto University, Kyoto, Japan; 2 Department of Neurology, Sapporo Medical University, Sapporo, Japan; 3 Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; 4 Clinical Research Center, Utano National Hospital, Kyoto, Japan; 5 Department of Neurobiology, Kyoto Pharmaceutical University, Kyoto, Japan
Epidemiological studies reported that paraquat, a hervicide, is one of the environmental risk factors of Parkinson disease. Paraquat induced apoptosis in PC12 cells. The endoplasmic reticulum (ER) stress was found to be involved in this paraquat -induced apoptosis because upregulation of CHOP and activation of Jun-N-terminal kinase (JNK), ER stress activated substrates, were observed. Upregulation of mRNA of BiP, an ER-specific chaperone, and splicing of the mRNA of the X box binding protein were observed, indicating the occurrence of the unfolded protein response (UPR). Prominent production of reactive oxygen species (ROS) was observed after paraquat exposure. Pre-incubation of phytoestrogens such as resveratrol prevalent in the red wine and genistein derived from soybean reduced the paraquat -induced ROS. Resvertrol reduced the UPR and increased the viability of PC12 cells was increased. In contrast, genistein was less effective to prevent the ER stress and the paraquat-induced cell death. Research fund: Grant from Fuji foundation for protein research.
P3-h39 Quantitative relationship of parkinsonian thalamic band activities with rigidity
Tomokazu Oshima, Yohsuke Narabayashi Narabayashi Memorial Laboratory of Neurology, Neurological Clinic, Tokyo, Japan Excess -band activities are observed in parkinsonian thalamic ventrolateral nucleus (VL). We examined how these activities were related with rigidity alleviated after the thalamotomy. Rigidity on the UPDRS and postoperative reduction (dR) were estimated in 100 patients with PD and 9 patients with essential tremor divided into six groups of rigidity preoperatively scored 0 (N), 0.5 (Ia), 1 (Ib), 2 (II), 3 (III), and 4 (IV). Filtered -band local field potentials (-waves) were quantified by the mean time integral (m) of 13–27 Hz wavelets in percent of 3-sec sample records. After the surgery, rigidity disappeared in groups Ia, Ib, and II, and remained partially in III or heavily in IV. The VL m was progressively increased through N, Ia, Ib to II, and decreased in III to IV. The m-to-dR relationship was positive, but non-linear of histeresis nature. The histeresis may arise by the time lag from the pathology represented by -waves to the expression of rigidity. The VL m represented only a part of severe rigidity, indicating that the late pathology involved other sites beyond the VL.
P3-h4Ø Neurosin cleaves the NAC region of ␣-synuclein
Takashi Kasai 1 , Takashi Kasai 1 , Takahiko Tokuda 1 , Toshiki Mizuno 1 , Masanori Nakagawa 1 , Yoshihisa Watanabe 1 , Nozomi Yamaguchi 1 , Fuyuki Kametani 2 1 Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan; 2 Tokyo Institute of Psychiatry, Tokyo, Japan Background: Neurosin is one of serine proteases predominantly expressed in a central nervous system. Neurosin is presumed to play an important role in metabolism of ␣-synuclein (␣-syn), because the previous report showed that neurosin exists in Lewy bodies and degrades ␣-syn in vitro. However the details of ␣-syn degradation by neurosin are little known. Method: Neurosin-mediated cleaving sites were investigated by LC/MS/MS. Degradations of wild and mutant ␣-syn by neurosin were evaluated by SDS-PAGE. Findings: The dominant cleavage site was between Lys80 and Thr81. Neurosin digested A30P mutant ␣-syn less efficiently than the wild type one. Interpretation: The dominant cleavage site we determined is the center of the NAC region, which is responsible for polymerization of the ␣-syn. This result suggests a hyothesis that neurosin inhibits the polymerization of ␣-syn by cleaving it in the NAC region.
Nicotinic receptor stimulation is protective for dopaminergic neuron
Nicotine could play a protective role for dopaminergic neuron, but its mechanism is still unclear. We demonstrated that nicotine prevented rotenone-induced dopaminergic cell death in primary cultures of rat ventral mesencephalon. The neuroprotection was inhibited by nicotinic acetylcholine rececptor (nAChR) antagonists, PI3 kinase inhibitor, and we uncovered elebvated pAkt/PKB by stimulating nAChRs, thus nicotine showed antiapoptotic effect via PI3 kinase-Akt/PKB pathway.Also we showed nicotine improved behavior and nigral dopaminergic cell loss of chronic rotenone-treated parkinsonian model mice (n = 8–12 per group). Stimulation of nAChRs may be useful as a treatment for Parkinson disease.
P3-h44 MPTP neurotoxicity is enhanced by a restraint stress in C57BL/6 mice
Daisuke Wada 1,2 , Atsushi Mori 1 , Satoru Nakai 1 , Naoki Kurihara 1 , Satoshi Ohashi 1 , Mitsuo Oshimura 2 , Masami Nakai 1 1 Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan; 2 Tottori University, Yonago, Japan
Although the pathogenesis of idiopathic Parkinson’s disease (PD) is not fully understood, a number of environmental factors as well as genetic ones are thought to contribute to the demise of dopaminergic neurons of nigrostriatal pathway. The neurotoxin 1-methyl-4-phenyl1,2,3,6-tetrahydropyridine (MPTP) has been used to create an animal model of PD in nonhuman primates and mice. This study investigated the effect of a various kinds of stress, one of the environmental factors, on dopaminergic neurodegeneration induced by MPTP intoxication. C57BL/6 mice were treated with single injection of MPTP (20 mg/kg, i.p.) and immediately exposed to stress for 2 h. We found that an exposure to restraint stress in MPTP-treated mice caused a severer loss of striatal nerve terminals as indicated by decreases in dopamine transporter protein levels as well as dopamine levels as compared with MPTP (alone)treated mice. This result suggests that restraint stress might promote the dopaminergic neurodegeneration in MPTP-treated mice.
P3-h45 Inhibition of catecholamine metabolism reduces ␣-synuclein related cytotoxicity in PC12 cells Satoru Ito Department of Neurology, Tottori University, Tottori, Japan
An intermediate polymer of quinone-binding ␣-synuclein (␣-syn) has been reported to show cytotoxicity in the pathogenesis of Parkinson’s disease. However, its detailed mechanism of action is still not well understood. We established PC12 cell lines that overexpress ␣-syn in a tetracyclineinducible manner and then examined their vulnerability against various stressors (MPP+ , Tunicamycin, Etoposide). An increased number of apoptotic cells (205%, 179%, 232%, respectively) were observed in the cells that overexpressed ␣-syn in comparison to cells not expressing ␣-syn. In addition, ␣-methyl-tyrosine, a specific inhibitor of tyrosine hydroxylase, reduced the number of apoptotic cells (26.3%, 49.6%, 62.5% reduction). Catecholamine is thus suggested to enhance cytotoxicity under various stressors such as ER stress, mitochondrial toxicity, genotoxic stress in cells demonstrating an overexpression of ␣-syn.