title: Differential regulation of glial cell line-derived neurotrophic factor (GDNF) mRNA expression during hypoxia and reoxygenation in astrocytes isolated from stroke-prone spontaneously hypertensive rats.
abstract: Glial cell line-derived neurotrophic factor (GDNF) plays several important roles in the survival and recovery of mature neurons during ischemia. We examined the possibility that the expression of GDNF mRNA and the release of GDNF protein are regulated differentially in cultured astrocytes from the stroke-prone spontaneously hypertensive rat (SHRSP) compared with those from Wistar Kyoto rats (WKY) during hypoxia and reoxygenation (H/R) and after exposure to glutamate and hydrogen peroxide (H(2)O(2)). The mRNA expression was quantitated by reverse transcription-polymerase chain reaction (RT-PCR) based on the fluorescent TaqMan methodology. A new instrument capable of measuring fluorescence in real-time was used to quantify gene amplification in astrocytes. GDNF protein was investigated by enzyme-linked immunosorbent assay (ELISA). GDNF mRNA expression and GDNF protein release at normoxia were greater in SHRSP than in WKY astrocytes. During H/R, however, the mRNA expression and protein release tended to be reduced in SHRSP compared with WKY. Glutamate and H(2)O(2) induced the expression of GDNF mRNA and the release of GDNF protein in both WKY and SHRSP in a dose-dependent manner. Levels of GDNF mRNA and protein in SHRSP were significantly lower than in WKY. These findings indicate that GDNF production in SHRSP astrocytes was low in response to H/R, glutamate, and H(2)O(2), compared with that observed in WKY. We conclude that the attenuated production of GDNF in astrocytes is involved in neuronal vulnerability in SHRSP during H/R, as GDNF production, which is stimulated by glutamate and H(2)O(2), is closely related to the protective effect against H/R-mediated neurotoxicity.
authors.affiliation: Division of Life Science, Graduate School of Integrated Science and Art, University of East Asia, Yamaguchi, Japan. yamagata@po.cc.toua-u.ac.jp
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yamagata
authors.forename: Motoki
authors.initials: M
authors.lastname: Tagami
authors.forename: Katsumi
authors.initials: K
authors.lastname: Ikeda
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Tsumagari
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yamori
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nara
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005333:Fetus; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D051100:Glial Cell Line-Derived Neurotrophic Factor; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020925:Hypoxia-Ischemia, Brain / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D015427:Reperfusion Injury / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D018698:Glutamic Acid; D006861:Hydrogen Peroxide