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Previous issue date: 2018-03-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Brain iron accumulation has been observed both in normal aging and in many neurodegenerative diseases. In previous studies, we have described that brain iron overload results in persistent memory deficits, accompanied by oxidative stress. The high metabolic rate of the nervous system makes mitochondria essential for nerve cells. These organelles control iron homeostasis in its interior and the management of reactive oxygen species. When deregulation in these activities occurs, mitochondrial functioning is compromised, resulting in failures in the energy supply mainly for the synapses. Inadequate functioning of neural circuits may culminate in the activation of cell death pathways, a feature strongly associated with neurodegenerative diseases. In the present study we analyzed the effects of neonatal iron overload on complex I deletions in the mitochondrial DNA ; on methylation and hydroxymethylation of mitochondrial DNA; on mitochondrial proteins involved on iron homeostasis, on the enzymatic activity of Succinate Dehydrogenase and Creatine Kinase, enzymes involved in the cells energy supply; and on proteins involved in apoptotic pathways, such as Caspase 8, Caspase 9, Caspase 3, Cytochrome c, APAF1, and PARP in the hippocampus of adult rats. In addition, we investigated the effects of cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa, in reversing iron-induced effects on all parameters analyzed. Male rats received vehicle or iron carbonyl (30 mg / kg) from the 12th to the 14th postnatal day and were treated with vehicle or CBD (10mg / kg) for 14 days in adulthood. Iron treatment induced increased deletions of mitochondrial DNA and expression of proteins involved in apoptosis, while induced reductions of methylation and hydroxymethylation, enzymatic activity and mitochondrial ferritin, an iron storage protein. CBD reversed iron-induced effects, recovering hydroxymethylation levels, mitochondrial ferritin, Succinate dehydrogenase activity, apoptotic proteins Caspase 3, Caspase 9, PARP and APAF1 at levels comparable to controls. These results suggest that iron can affect mechanisms of mitochondrial functioning and trigger cell death pathways by apoptosis. The reversal of some of these effects by CBD indicates its neuroprotective potential. / O ac?mulo de ferro no c?rebro tem sido observado tanto no envelhecimento normal quanto em muitas doen?as neurodegenerativas. Nossos estudos anteriores mostraram que a sobrecarga de ferro cerebral resulta em d?ficits de mem?ria persistentes, acompanhados por estresse oxidativo. A elevada taxa metab?lica do sistema nervoso torna as mitoc?ndrias essenciais para c?lulas nervosas. Essas organelas t?m como fun??o o controle da homeostasia do ferro em seu interior e o gerenciamento das esp?cies reativas de oxig?nio. Uma vez que ocorre desregula??o nessas atividades, o funcionamento das mitoc?ndrias fica comprometido, resultando em falhas no aporte energ?tico principalmente para as sinapses. O funcionamento inadequado de circuitos neurais pode culminar na ativa??o de vias de morte celular, uma caracter?stica bastante associada ?s doen?as neurodegenerativas. No presente trabalho analisamos os efeitos da sobrecarga de ferro neonatal sobre as dele??es no complexo I do DNA mitocondrial; sobre os mecanismos de metila??o e hidroximetila??o do DNA mitocondrial; sobre prote?nas envolvidas no metabolismo de ferro mitocondrial (Ferritina mitocondrial e Mitoferrina 2), sobre a atividade enzim?tica da Succinato desidrogenase e Creatina quinase, envolvidas no aporte energ?tico para as c?lulas; e sobre prote?nas envolvidas nas vias apopt?ticas, como a Caspase 8, Caspase 9, Caspase 3, Citocromo c, APAF1 e PARP em hipocampos de ratos adultos. Al?m disso, investigamos os efeitos do canabidiol (CBD), principal componente n?o psicotr?pico da Cannabis sativa, na revers?o dos efeitos induzidos pelo ferro sobre todos os par?metros analisados. Ratos machos receberam ve?culo ou ferro carbonila (30 mg/kg) do 12? ao 14? dia p?s-natal e na idade adulta foram tratados com ve?culo ou CBD (10 mg/kg) durante 14 dias. O tratamento com ferro induziu o aumento das dele??es do DNA mitocondrial e das prote?nas envolvidas na via intr?nseca da apoptose, enquanto induziu a redu??o de metila??o e hidroximetila??o no DNA mitocondrial, bem como da atividade enzim?tica e da ferritina mitocondrial, prote?na de armazenamento de ferro. O CBD reverteu os efeitos induzidos pelo ferro, recuperando os n?veis de hidroximetila??o, de ferritina mitocondrial, da atividade da Succinato dehidrogenase, e das prote?nas apopt?ticas Caspase 3, Caspase 9, PARP e APAF1 a n?veis compar?veis com o controle. Os resultados sugerem que o ferro pode afetar mecanismos de funcionamento mitocondrial e desencadear vias de morte celular por apoptose. A revers?o de alguns desses efeitos pelo CBD indica o seu potencial neuroprotetor.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7949 |
| Date | 07 March 2018 |
| Creators | Silva, Vanessa Kappel da |
| Contributors | Schr?der, Nadja |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, Brasil, Escola de Ci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 500, 500, 600, -1634559385931244697, 2075167498588264571 |
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