Neuronal and glial responses in the brain under hypoxic stress

2011 Fiscal Year Final Research Report

• Project/Area Number: 21592302
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Emergency medicine
• Research Institution: Yamagata University
• Principal Investigator: ISEKI Ken 山形大学, 医学部, 准教授 (70332921)
• Co-Investigator(Kenkyū-buntansha): GOTO Kaoru 山形大学, 医学部, 教授 (30234975)
• Project Period (FY): 2009 – 2011
• Keywords: 生体ストレス応答 / OGD酸素グルコース欠乏 / 海馬神経細胞 / 核内脂質代謝酵素 / 細胞死

Research Abstract

Diacylglycerol kinase (DGK) plays a key role in pathophysiological cellular responses by regulating the levels of a lipid messenger diacylglycerol. Of DGK isozymes, DGKζ localizes to the nucleus in various cells such as neurons. We previously reported that DGKζ translocates from the nucleus to the cytoplasm in hippocampal CA1 pyramidal neurons after 20 min of transient forebrain ischemia. In this study, we examined the underlying mechanism of DGKζ translocation using hippocampal slices exposed to oxygen-glucose deprivation (OGD) to simulate an ischemic model of the brain. DGKζ-immunoreactivity gradually changed from the nucleus to the cytoplasm in CA1 pyramidal neurons after 20 min of OGD and was never detected in the nucleus after reoxygenation. Intriguingly, DGKζ was detected in the nucleus at 10 min OGD whereas the following 60 min reoxygenation induced complete cytoplasmic translocation of DGKζ. Morphometric analysis revealed that DGKζ cytoplasmic translocation correlated with nuclear shrinkage indicative of an early process of neuronal degeneration. The translocation under OGD conditions was blocked by NMDA receptor (NMDAR) inhibitor, and was induced by activation of NMDAR. Chelation of the extracellular Ca(2+) blocked the translocation under OGD conditions. These results show that DGKζ cytoplasmic translocation is triggered by activation of NMDAR with subsequent extracellular Ca(2+) influx. Furthermore, inhibition of PKC activity under OGD conditions led to nuclear retention of DGKζ in about one-third of the neurons, suggesting that PKC activity partially regulates DGKζ cytoplasmic translocation. These findings provide clues to guide further investigation of glutamate excitotoxicity mechanisms in hippocampal neurons.

Research Products

• [Journal Article] NMDA receptor-mediated Ca(2+) influx triggers nucleocytoplasmic translocation of diacylglycerol kinase ζ under oxygen-glucose deprivation conditions, an in vitro model of ischemia, in rat hippocampal slices (2012)
  • Author(s): Suzuki Y, Yamazaki Y, Hozumi Y, Okada M, Tanaka T, Iseki K, Ohta N, Aoyagi M, Fujii S, Goto K
  • Journal Title: Histochem Cell Biol Volume: 137(4) Pages: 499-511
  • Peer Reviewed
• [Journal Article] Altered expression pattern of testican-1 mRNA after brain injury (2011)
  • Author(s): Iseki K, Hagino S, Zhang Y, Mori T, Sato N, Yokoya S, Hozumi Y, Goto K, Tase C
  • Journal Title: Biomed Res Volume: 32(6) Pages: 373-8
  • Peer Reviewed
• [Journal Article] Identification of a functional nuclear export sequence in diacylglycerol kinase-zeta (2010)
  • Author(s): Evangelisti C, Gaboardi GC, Billi AM, Ognibene A, Goto K, Tazzari PL, McCubrey JA, Martelli AM
  • Journal Title: Cell Cycle Volume: 9(2) Pages: 384-8
  • Peer Reviewed
• [Journal Article] Signaling Cascade of Diacylglycerol Kinase β in the Pituitary Intermediate Lobe : Dopamine D2 Receptor/PhospholipaseC β 4/Diacylglycerol Kinase β/Protein Kinase C_α (2009)
  • Author(s): Hozumi Y, Watanabe M, Goto K.
  • Journal Title: J Histochem Cytochem
  • Peer Reviewed
• [Journal Article] Brain trauma induces expression of diacylglycerol kinase zeta in microglia (2009)
  • Author(s): Nakano T, Iseki K, Hozumi Y, Kawamae K, Wakabayashi I, Goto K
  • Journal Title: Neurosci Lett Volume: 461(2) Pages: 110-5
  • Peer Reviewed
• [Journal Article] Localization of diacylglycerol kinase epsilon on stress fibers in vascular smooth muscle cells (2009)
  • Author(s): Nakano T, Hozumi Y, Goto K, Wakabayashi I
  • Journal Title: Cell Tissue Res Volume: 337(1) Pages: 167-75
  • Peer Reviewed
• [Journal Article] Diacylglycerol kinase beta promotes dendritic outgrowth and spine maturation in developing hippocampal neurons (2009)
  • Author(s): Hozumi Y, Watanabe M, Otani K, Goto K
  • Journal Title: BMC Neurosci Volume: 10 Pages: 99
  • Peer Reviewed
• [Presentation] Nuclear assembly proteinはDGKζの核細胞質間輸送を制御する (2010)
  • Author(s): 岡田雅司, 後藤薫
  • Organizer: 第33回日本分子生物学会・第83回日本生化学大会合同大会
  • Place of Presentation: 神戸、神戸国際会議場
  • Year and Date: 20101207-10
• [Presentation] 細胞質局在型ジアシルグリセロールζは細胞死を抑制する (2010)
  • Author(s): 田中俊昭, 後藤薫
  • Organizer: 日本解剖学会東北・北海道連合支部学術集会
  • Place of Presentation: 旭川、旭川医科大学
  • Year and Date: 20100925-26
• [Presentation] 海馬スライスにおける酸素グルコース欠乏負荷によるζ型ジアシルグリセロールキナーゼの細胞内局在の変化 (2009)
  • Author(s): 鈴木祐輔, 後藤薫
  • Organizer: 第55回日本解剖学会東北・北海道連合支部学術集会
  • Place of Presentation: 仙台、東北大学医学部
  • Year and Date: 20090926-27
• [Presentation] Nucleocytoplasmic translocation of diacylglycerol kinase zeta under oxygen and glucose deprivation in rat hippocampal slices (2009)
  • Author(s): Suzuki Y, Yamazaki Y, Kaneko K, Fujii S, Iseki K, Goto K
  • Organizer: 39th Annual Meeting of Neuroscience
  • Place of Presentation: シカゴ、アメリカ
  • Year and Date: 2009-10-18
• [Presentation] Upregulation of agrin in the reactive astrocytes after brain injury (2009)
  • Author(s): Iseki K, Goto K
  • Organizer: 9th European Meeting on Glial Cells
  • Place of Presentation: パリ、フランス
  • Year and Date: 2009-09-11