title: Combined metabolic and transcriptional profiling identifies pentose phosphate pathway activation by HSP27 phosphorylation during cerebral ischemia.
abstract: The metabolic pathophysiology underlying ischemic stroke remains poorly understood. To gain insight into these mechanisms, we performed a comparative metabolic and transcriptional analysis of the effects of cerebral ischemia on the metabolism of the cerebral cortex using middle cerebral artery occlusion (MCAO) rat model. Metabolic profiling by gas-chromatography/mass-spectrometry analysis showed clear separation between the ischemia and control group. The decreases of fructose 6-phosphate and ribulose 5-phosphate suggested enhancement of the pentose phosphate pathway (PPP) during cerebral ischemia (120-min MCAO) without reperfusion. Transcriptional profiling by microarray hybridization indicated that the Toll-like receptor and mitogen-activated protein kinase (MAPK) signaling pathways were upregulated during cerebral ischemia without reperfusion. In relation to the PPP, upregulation of heat shock protein 27 (HSP27) was observed in the MAPK signaling pathway and was confirmed through real-time polymerase chain reaction. Immunoblotting showed a slight increase in HSP27 protein expression and a marked increase in HSP27 phosphorylation at serine 85 after 60-min and 120-min MCAO without reperfusion. Corresponding upregulation of glucose 6-phosphate dehydrogenase (G6PD) activity and an increase in the NADPH/NAD+ratio were also observed after 120-min MCAO. Furthermore, intracerebroventricular injection of ataxia telangiectasia mutated (ATM) kinase inhibitor (KU-55933) significantly reduced HSP27 phosphorylation and G6PD upregulation after MCAO, but that of protein kinase D inhibitor (CID755673) did not affect HSP27 phosphorylation. Consequently, G6PD activation via ischemia-induced HSP27 phosphorylation by ATM kinase may be part of an endogenous antioxidant defense neuroprotection mechanism during the earliest stages of ischemia. These findings have important therapeutic implications for the treatment of stroke.
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Taichiro
authors.initials: T
authors.lastname: Imahori
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. Electronic address: khosoda@med.kobe-u.ac.jp.
authors.forename: Kohkichi
authors.initials: K
authors.lastname: Hosoda
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nakai
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Division of Evidence-based Laboratory Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Irino
authors.affiliation: The Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Shinohara
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Sato
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasayama
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nagashima
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kohta
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kohmura
mesh_terms: D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001572:Benzofurans / Q000494:pharmacology; D002545:Brain Ischemia / Q000188:drug therapy / Q000378:metabolism*; D004195:Disease Models, Animal; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D010427:Pentose Phosphate Pathway / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D011753:Pyrones / Q000494:pharmacology; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C495818:2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one; D001381:Azepines; D001572:Benzofurans; C534615:CID755673; D055551:HSP27 Heat-Shock Proteins; C486114:Hspb1 protein, rat; D009025:Morpholines; D011753:Pyrones; D020928:Mitogen-Activated Protein Kinases
keywords: cerebral ischemia; glucose 6-phosphate dehydrogenase; heat shock protein 27; middle cerebral artery occlusion; omics; pentose phosphate pathway