title: A new role for 5-methoxytryptophol on bone cells function in vitro.
abstract: The present study investigates the direct action of 5-methoxytryptophol (5-MTX) in both MC3T3-E1 and RAW264.7 cells and compares it with melatonin (MEL), another 5-methoxyindol known to play a significant role on bone metabolism. We first screened increasing doses of both 5-MTX and MEL to determine their effect on metabolic activity and viability of preosteoblastic MC3T3-E1 cells. The optimal dose was used to determine its effect on differentiation of MC3T3-E1 cells and preosteoclastic RAW264.7 cells. Finally, we investigated the mechanism of action by adding the melatonin receptor antagonist luzindole (LUZ) and detecting the immunostaining of phospho-ERK. In MC3T3-E1 cells, most of the 5-MTX doses reduced slightly the metabolic activity of osteoblasts compared with the control, while MEL only decreased it for the highest dose (2.5 mM). As regards to cytotoxicity, low doses (0.001-0.1 mM) of both indoles showed a protective effect on osteoblasts, while the highest dose of MEL showed a higher cytotoxicity than the 5-MTX one. After 14 days of cell culture, Rankl mRNA levels were decreased, especially for 5-MTX. 5-MTX also induced a higher osteocalcin secretion and mineralization capacity than MEL. In RAW264.7 cells, 5-MTX decreased the number of osteoclast formed and its activity whereas MEL did not affect significantly the number of multinucleated TRAP-positive cells formed and showed a lower activity. Finally, MEL and 5-MTX promoted activation of the ERK1/2 pathway through the phosphorylation of ERK, while LUZ addition suppressed this effect. In conclusion, the present study demonstrates a new role of 5-MTX inhibiting osteoclastogenesis and promoting osteoblast differentiation.
authors.affiliation: Group of Cell Therapy and Tissue Engineering, Research Institute on Health Sciences (IUNICS). University of Balearic Islands, Palma de Mallorca, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Satué
authors.forename: Joana Maria
authors.initials: JM
authors.lastname: Ramis
authors.forename: Maria
authors.initials: M
authors.lastname: del Mar Arriero
authors.forename: Marta
authors.initials: M
authors.lastname: Monjo
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects*; D010010:Osteoclasts / Q000187:drug effects*; D053245:RANK Ligand / Q000235:genetics; D014363:Tryptamines / Q000494:pharmacology
chemical_list: D007211:Indoles; D053245:RANK Ligand; C505688:TNFSF11 protein, human; D014363:Tryptamines; C057154:luzindole; C002465:methoxytryptophol; D008550:Melatonin
keywords: 5-METHOXYTRYPTOPHOL; BONE REMODELING; MELATONIN; OSTEOBLAST; OSTEOCLAST