title: Regulatory roles of bone morphogenetic proteins and glucocorticoids in catecholamine production by rat pheochromocytoma cells.
abstract: We here report a new physiological system that governs catecholamine synthesis involving bone morphogenetic proteins (BMPs) and activin in the rat pheochromocytoma cell line, PC12. BMP type I receptors, including activin receptor-like kinase-2 (ALK-2) (also referred to as ActRIA) and ALK-3 (BMPRIA), both type II receptors, ActRII and BMPRII, as well as the ligands BMP-2, -4, and -7 and inhibin/activin subunits were expressed in PC12 cells. PC12 cells predominantly secrete dopamine, whereas noradrenaline and adrenaline production is negligible. BMP-2, -4, -6, and -7 and activin A each suppressed dopamine and cAMP synthesis in a dose-dependent fashion. The BMP ligands also decreased 3,4-dihydroxyphenylalanine decarboxylase mRNA expression, whereas activin suppressed tyrosine hydroxylase expression. BMPs induced both Smad1/5/8 phosphorylation and Tlx2-Luc activation, whereas activin stimulated 3TP-Luc activity and p38 MAPK phosphorylation. ERK signaling was not affected by BMPs or activin. Dexamethasone enhanced catecholamine synthesis, accompanying increases in tyrosine hydroxylase and 3,4-dihydroxyphenylalanine decarboxylase transcription without cAMP accumulation. In the presence of dexamethasone, BMPs and activin failed to reduce dopamine as well as cAMP production. In addition, dexamethasone modulated mitotic suppression of PC12 induced by BMPs in a ligand-dependent manner. Furthermore, intracellular BMP signaling was markedly suppressed by dexamethasone treatment and the expression of ALK-2, ALK-3, and BMPRII was significantly inhibited by dexamethasone. Collectively, the endogenous BMP/activin system plays a key role in the regulation of catecholamine production. Controlling activity of the BMP system may be critical for glucocorticoid-induced catecholamine synthesis by adrenomedullar cells.
authors.affiliation: Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kano
authors.forename: Fumio
authors.initials: F
authors.lastname: Otsuka
authors.forename: Masaya
authors.initials: M
authors.lastname: Takeda
authors.forename: Jiro
authors.initials: J
authors.lastname: Suzuki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Inagaki
authors.forename: Tomoko
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Manabu
authors.initials: M
authors.lastname: Miyamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Otani
authors.forename: Toshio
authors.initials: T
authors.lastname: Ogura
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Makino
mesh_terms: D028341:Activins / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D052004:Bone Morphogenetic Protein Receptors / Q000378:metabolism; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D002395:Catecholamines / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000037:antagonists & inhibitors; D003907:Dexamethasone / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D005938:Glucocorticoids / Q000378:metabolism* / Q000494:pharmacology; D028322:Inhibin-beta Subunits / Q000494:pharmacology; D008024:Ligands; D008938:Mitosis / Q000187:drug effects; D016716:PC12 Cells / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D002395:Catecholamines; D018492:Dopamine Antagonists; D005938:Glucocorticoids; D008024:Ligands; D051785:Smad Proteins; C422405:activin A; D028341:Activins; D003907:Dexamethasone; D028322:Inhibin-beta Subunits; D000242:Cyclic AMP; D052004:Bone Morphogenetic Protein Receptors