一般演題（ポスター）

一般演題（ポスター） Neuronal Death・Apoptosis

1P-31 Age-related cell death of Drosophila Or42b neurons is induced by activation of innate immune response Takeuchi Kenichi¹，Chihara Takahiro^1,2，Miura Masayuki^1,2 ¹Graduate school of Pharm. Sci., Univ of Tokyo，²CREST, JST During normal aging or in neurodegenerative diseases, our brain functions such as cognition and memory get decline. However, the mechanisms of age-related impairments in brain function during normal aging are not well known. Here we show that age-related caspase activation and cell death of specific neuron is caused by activation of innate immune response.Recently, we found that caspase, the executor protease of apoptosis is activated in a subset of olfactory receptor neurons（ORNs）, especially in Or42b neurons during normal aging（PLOS Genetics 10, e1004437, 2014）. ORN is the first order neuron of Drosophila olfactory system, and Or42b neuron is known to be necessary and sufficient for innate attractive behavior to food-like odors. Thus, aging can affect the defined animal behavior by affecting the death of specific neurons, such as Or42b neurons. In this report, we investigate the molecular mechanism underlying the age-related caspase activation in Or42b neurons.To investigate the impact of aging on ORNs including Or42b neurons, we first performed gene expression profiling of young or aged antenna with microarray analysis. We found that expression of antimicrobial peptide（AMP）genes were significantly up-regulated in aged antenna, suggesting that innate immune response is induced in aged antenna. Consistent with this, age-related caspase activation was suppressed in mutants for innate immune response. These results indicate that caspase activation is the consequence of activated innate immune response. Our results suggest the possible link between innate immune response and age-related decline of brain functions during normal aging.		1P-32 ER and Golgi stresses upregulate ER-Golgi SNARE Syntaxin5 and suppress Aβ peptide secretion in primary hippocampal neurons Suga Kei，SAITO AYAKO，MISHIMA TATSUYA，AKAGAWA KIMIO Dept. Cell Physiol., Kyorin Univ. Sch. of Med. Endoplasmic reticulum（ER）stress has been implicated in neurodegenerative diseases such as Alzheimer’s disease（AD）. We have been focusing on the neuronal function of ER-Golgi soluble N-ethylmaleimide-sensitive factor-attachment protein receptors（ER-Golgi SNAREs）. We previously demonstrated that manipulation of Syntaxin5（Syx5）protein causes changes in the Golgi morphology and processing of AD-related proteins such as β-amyloid precursor protein（βAPP）. We also showed that ER stress upregulates de novo synthesis of ER-Golgi SNAREs Syx5 and Bet1 in Neuroblastoma-Glioma hybrid cell line NG108-15（Suga K. et al., Exp. Cell Res., 2015）. In addition, while ER stress caused the reduction of β-amyloid peptide（Aβ peptide）secretion during the adaptive stage of the response, knockdown of Syx5 proteins enhanced the secretion of Aβ. Furthermore, reduction in Aβ secretion by ER stress was significantly suppressed by Syx5 knock down. However, it is neither clear how such stress signal propagates from the ER through the Golgi apparatus, nor how it affects the transport and the processing of AD-related proteins in neurons. In this study, to clarify the role of Syx5 proteins in neuronal βAPP processing and viability, we examined the effects of ER and Golgi stress on the expression of ER-Golgi SNAREs, βAPP processing, and cell viability in hippocampal culture neurons. We found that whereas ER stress and Golgi stress caused upregulation of Syx5 proteins, apoptosis induction using Staurosporine caused down regulation of Syx5 proteins due to the degradation by activated Caspase-3. Knockdown of Syx5 protein under ER stress enhanced vulnerability of neurons. In addition, Golgi stress decreases the secretion of Aβ peptides from neurons as in ER stress. These findings suggest that ER-Golgi SNARE Syx5 serve as a new responder to Golgi stress and regulates Aβ peptide secretion and affects neuronal survival during organelle stress.

1P-33 Reactive oxygen species-generating activity in lysosomes contributes to an iron-dependent form of cell death Shintoku Ryosuke^1,2，Kubota Chisato¹，Yaegashi Makoto¹，Yoshimoto Yuhei²，Torii Seiji¹ ¹Secretion Biology Lab, Institute for Molecular and Cellular Regulation, Gunma University，²Department of Neurosurgery, Gunma University Graduate School of Medicine Oxidative stress-induced cell death has been implicated in acute injury such as ischemia. Here we assessed a novel type of oxidative cell death, ferroptosis, which requires intracellular iron. We found that ferroptotic compounds-induced cell death could be prevented by inhibitors of autophagic/lysosomal activity. Analyses with a fluorescent reactive oxygen species（ROS）sensor revealed constitutive formation of ROS in endo-lysosomes, and treatment with lysosome inhibitors decreased both lysosomal ROS and a cell death-associated ROS burst. These inhibitors partially prevented intracellular iron usage by attenuating intracellular transport of transferrin or autophagic degradation of ferritin. Furthermore, fluorescent analyses with a membrane peroxidation sensor represented formation of lipid peroxidation in these compartments. Thus, lysosomal activity may be involved in ferroptosis by modulating iron equilibria and ROS formation. Our spatiotemporal analysis with effective probes will contribute to understand the mechanisms of neural cell death during cerebral ischemia.		1P-34 Effect of Arginine methylation via PRMT1 on organella Amano Genki¹，Matsuzaki Sinsuke^1,2，Mukai Haruka¹，Mori Yasutake²，Takamura Hironori¹，Sato Hiroki¹，Han Sarina¹，Miyoshi Ko¹，Katayama Taiichi¹ ¹Molecular Brain Science, United Graduate School of Child Development,Osaka University，²Anatomy and Neuroscience, Graduate School of Medicine,Osaka University Cumulative of reports have shown the importance of ER stress in pathology of neurodegenerative diseases, such as Alzheimer’s disease, Parkinson disease, etc. These studies indicate that the cellular events in response to ER stress should relate to the pathology of neurodegenerative diseases. To elucidate the pathogenesis of neurodegenerative diseases from the point of ER stress, we investigated the altered genes in SK-N-SH cells in the condition of tunicamycin-induced ER stress by gene fishing method. As the result, we found that Protein arginine N-methyltransferase 1, PRMT1, is up-regulated in SK-N-SH cells under ER stress. Based on this result, we examined the importance of PRMT1 in the ER stress pathway and cell, PRMT1 permanently knock down cells were constructed and the cells showed the abnormal golgi formation and increased UPR, unforded protein resonse. To elucidate the mechanism of such alterations, we screened the methylated proteins under ER stress condition by IP-MS and we got several candidates. In this poster, we showed the effect of methylation on the physiological functions of them.