An evaluation of the neuroprotective effects of melatonin in an in vitro experimental model of age-induced neuronal apoptosis.
The neuroprotective effects of melatonin in an experimental model of aging-induced apoptosis have been examined. Cerebellar granule neurons show characteristics of apoptosis after 17 days in culture (DV). The addition of melatonin to neuronal cell cultures (100-500 mum) resulted in neuroprotective and antiapoptotic effects, which were revealed by nuclear condensed cell counting. In a thorough analysis by Western-blot of the potential pathways responsible for melatonin's neuroprotective effects, we found an increase in the activation of prosurvival Akt. Subsequently GSK3beta inhibition and an increase in p-FOXO1 phosphorylation occurred. In this model of aging, apoptosis was associated with an elevated DNA damage, as demonstrated by an increase in the activation of ataxia telangiectasia muted (ATM). Subsequently, downstream targets such as p53 were activated. Furthermore, the process of DNA damage was coupled to an increase in the expression of certain proteins involved in cell cycle regulation; these were cyclin D and the proapoptotic transcription factor E2F-1. We conclude that the antiapoptotic effects of melatonin were mediated by two potential mechanisms: by increasing the activity of prosurvival pathways via Akt and by the prevention of DNA damage (via ATM inhibition) followed by the reduction of cell cycle re-entry.
Tajes Orduña
Marta
M
Centro de Investigación de Biomedicina en Red en Enfermedades Neurodegenerativas (CIBERNED), Unitat de Farmacologia i Farmacognòsia and Institut de Biomedicina (IBUB), Barcelona, Spain.
Pelegrí Gabalda
Carme
C
Vilaplana Hortensi
Jordi
J
Pallàs Lliberia
Mercè
M
Camins Espuny
Antoni
A
D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D016922:Cellular Senescence; D002531:Cerebellum / Q000166:cytology; D056741:Cyclin D; D016213:Cyclins / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D050687:E2F1 Transcription Factor / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D008550:Melatonin / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000975:Antioxidants; D056741:Cyclin D; D016213:Cyclins; D050687:E2F1 Transcription Factor; D018696:Neuroprotective Agents; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D008550:Melatonin