title: Sargaquinoic acid promotes neurite outgrowth via protein kinase A and MAP kinases-mediated signaling pathways in PC12D cells.
abstract: We previously isolated a nerve growth factor (NGF)-dependent neurite outgrowth promoting substance MC14 (sargaquinoic acid) from a marine brown alga, Sargassum macrocarpum. In the present study, the NGF-potentiating activity of MC14 to neural differentiation of PC12D cells was investigated in detail. The treatment of cells with 3 microg/ml MC14 in the presence of 1.25-100 ng/ml NGF markedly enhanced the proportion of neurite-bearing cells compared with the NGF-only controls. In addition, MC14 significantly elevated the NGF-induced specific acetylcholinesterase (AchE) activity in PC12D cells, suggesting that MC14 could morphologically and biochemically promote the differentiation of PC12D cells. The mechanism of action of MC14 was further investigated by pharmacological inhibition of several intracellular signaling molecules. Results indicated that the neurite outgrowth promoting activity of MC14 was almost completely blocked by 10 microM PD98059, suggesting that a TrkA-dependent MAP kinases-mediated signaling pathway may play a crucial role in modulating the effect of MC14. Besides, the MC14-enhanced neurite outgrowth was substantially suppressed by the pretreatment with 10 ng/ml protein kinase A (PKA) inhibitor, demonstrating that the adenylate cyclase-PKA signaling cascade was also involved in the action of MC14. In contrast, a PKC inhibitor chelerythrine chloride did not inhibit the neurite outgrowth promoting activity of MC14. Altogether, these results demonstrate that MC14 enhances the neurite outgrowth by cooperating at least two separated signaling pathways, a TrkA-MAP kinases pathway and an adenylate cyclase-PKA pathway, in PC12D cells.
authors.affiliation: Marine and Highland Bioscience Center, Saga University, 152-1 Shonan-cho, Karatsu, Saga 847-0021, Japan. kameiy@cc.saga-u.ac.jp
authors.forename: Yuto
authors.initials: Y
authors.lastname: Kamei
authors.forename: Chi Kwan
authors.initials: CK
authors.lastname: Tsang
mesh_terms: D000110:Acetylcholinesterase / Q000187:drug effects; D000475:Alkenes / Q000494:pharmacology*; D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology*; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D017868:Cyclic AMP-Dependent Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects* / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats
chemical_list: D000475:Alkenes; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D005419:Flavonoids; C477718:sargaquinoic acid; D020932:Nerve Growth Factor; D017868:Cyclic AMP-Dependent Protein Kinases; D000110:Acetylcholinesterase; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one