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α 2 adrenoreceptor agonist regulates protein kinase C‐induced heat shock protein 27 phosphorylation in C6 glioma cells
Author(s) -
Tanabe Kumiko,
Takai Shinji,
MatsushimaNishiwaki Rie,
Kato Kanefusa,
Dohi Shuji,
Kozawa Osamu
Publication year - 2008
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2008.05389.x
Subject(s) - adenylyl cyclase , forskolin , phosphorylation , protein kinase c , protein kinase a , hsp27 , neuroprotection , agonist , gs alpha subunit , chemistry , endocrinology , activator (genetics) , medicine , hsp70 , microbiology and biotechnology , biology , pharmacology , heat shock protein , signal transduction , biochemistry , receptor , gene
Dexmedetomidine (Dexmd), a potent and highly specific α 2 adrenoreceptor agonist, is an efficient therapeutic agent for sedation. Dexmd has been recently reported to have a neuroprotective effect. Heat shock protein (HSP) 27, a low‐molecular weight HSP has been shown to be expressed following cerebral ischemia in astrocytes but not in neurons. HSP27 expression is involved in ischemic tolerance of the brain. This study investigated the effect of Dexmd on HSP27 in rat C6 glioma cells. 12‐ O ‐tetradecanoylphorbol‐13‐actate (TPA), a direct activator of protein kinase C (PKC), stimulated the phosphorylation of HSP27 at Ser82, but not Ser15 in a time‐dependent manner. Prostaglandin (PG) E 1 or PGE 2 which activates the adenylyl cyclase‐cAMP system as well as forskolin and dibutyryl‐cAMP, suppressed the TPA‐induced phosphorylation of HSP27. Dexmd reversed the suppression of HSP27 phosphorylation by the adenylyl cyclase‐cAMP system. Therefore, these results strongly suggest that Dexmd reverses the suppression of HSP27 phosphorylation by the adenylyl cyclase‐cAMP system activation through the inhibition of its system in C6 cells. α 2 Adrenoreceptor agonists may therefore show a neuroprotective effect through the modification of HSP27 phosphorylation induced by PKC activation.