Activation of trasnscription fator <font face=\"Symbol\">kB induced by alpha-synuclein in SH-SY5Y cells.

A Doença de Parkinson (DP) é um distúrbio neurodegenerativo. Suas características e seus sintomas neuropatológicos são bem definidos, mas sua etiologia ainda continua desconhecida. A DP esporádica é caracterizada anatomo-patologicamente pela presença de Corpos de Lewy, que são agregados lipoproteicos que se encontram no interior do neurônio. A a-sinucleína é uma proteína solúvel presente nos terminais pré-sinápticos de vários sistemas de transmissão. Evidências sugerem que esta proteína é um componente fundamental dos Corpos de Lewy localizados nos neurônios dopaminérgicos do sistema nigroestrital de pacientes portadores de DP. Postula-se que a a-sinucleína possui uma função fundamental na patogênese da DP, pois pode afetar a homeostase de neurônios dopaminérgicos, levando ao aumento da dopamina no citosol e consequente estresse oxidativo. O fator de transcrição nuclear kappa B (NF-kB) participa da regulação de respostas imunes, inflamatórias e morte celular. No sistema nervoso central este fator está presente em diversos tipos de células nervosas e seu papel é paradoxal, ora apontado como neurotóxico, ora como neuroprotetor. O NFkB pode ser estimulado por vários fatores entre eles neurotransmissores (por exemplo: dopamina e glutamato), estresse e proteína b-amilóide. Neste trabalho, pretendemos estudar as modificações moleculares nas células SH-SY5Y transduzidas com a a-sinucleína na sua forma selvagem (WT), mutante (A30P) e truncada (1-120) e tratadas com meio condicionado (CM) (proveniente do tratamento da glia com LPS) ou TNF. Analisamos a modulação da atividade do NF-kB, onde observamos o aumento da atividade quando as células foram tratadas com TNF mas não com CM. Ainda, observamos que ocorre diminuição da fosforilação da proteína MAPK42/44 durante o mesmo tratamento, e que esta diminuição pode estar ligada ao aumento da morte celular.Parkinsons Disease (PD) is a neurodegenerative disease. The characteristics and symptoms are well defined; nevertheless its etiology remains unknown. The sporadic PD is characterized by the presence of Lewy Body (aggregate of proteins) inside the neurons. Alpha-synuclein is a soluble protein present in the pre synaptic terminal of neurons. Evidences suggest that this protein is a fundamental component of Lewy bodies localized in the dopaminergic neurons of PD patients. It is already known that alpha-synuclein has a fundamental role in pathogenesis of PD, because it can affect the homeostasis of dopaminergic neurons, leading to increase of dopamine in the cytosol and consequent oxidative stress. The nuclear transcription factor kB (NF-kB) regulates the immune, inflammatory and cell death responses. In the central nervous system, this factor is present in several types of cells and its role is paradoxal, since it can be neurotoxic or can be protective. The NFkB can be stimulated by several factors, including dopamine, glutamate, stress and b-amyloid protein. In this work, we observed the molecular modification in SH-SY5Y cells transduced with alpha-synuclein (wild-type, A30P and truncated 1-120) and treated with conditioned medium (CM) (from primary culture of glia treated with LPS) or TNF. We analyzed the modulation of NF-kB activity, in which was observed that the activity was increased when the cells were treated with TNF but not with CM. Moreover, we show that there is a decrease of MAPK42/44 phosphorilation during the treatment, and this decrease is linked to the increase of cell death of these cells overexpressing alpha-synulein

Influence of N-methyl-D-aspartate receptors on ouabain activation of nuclear factor-kappa B in the rat hippocampus

It has been shown that ouabain (OUA) can activate the Na,K-ATPase complex and mediate intracellular signaling in the central nervous system (CNS). Inflammatory stimulus increases glutamatergic transmission, especially at N-methyl-D-aspartate (NMDA) receptors, which are usually coupled to the activation of nitric oxide synthase (NOS). Nuclear factor-kappa B (NF-kappa B) activation modulates the expression of genes involved in development, plasticity, and inflammation. The present work investigated the effects of OUA on NF-kappa B binding activity in rat hippocampus and the influence of this OUA-Na,K-ATPase signaling cascade in NMDA-mediated NF-kappa B activation. The findings presented here are the first report indicating that intrahippocampal administration of OUA, in a concentration that did not alter Na,K-ATPase or NOS activity, induced an activation of NF-kappa B, leading to increases in brain-derived neurotrophic factor (Bdnf), inducible NOS (iNos), tumor necrosis factor-alpha (Tnf-alpha), and B-cell leukemia/lymphoma 2 (Bcl2) mRNA levels. This response was not linked to any significant signs of neurodegeneration as showed via Fluoro-Jade B and Nissl stain. Intrahippocampal administration of NMDA induced NF alpha B activation and increased NOS and alpha 2/3-Na,K-ATPase activities. NMDA treatment further increased OUA-induced NF-kappa B activation, which was partially blocked by MK-801, an antagonist of NMDA receptor. These results suggest that OUA-induced NF-kappa B activation is at least in part dependent on Na,K-ATPase modulatory action of NMDA receptor in hippocampus. The interaction of these signaling pathways could be associated with biological mechanisms that may underlie the basal homeostatic state linked to the inflammatory signaling cascade in the brain. (c) 2011 Wiley Periodicals, Inc.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP [2003/08989-0]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq [485953-2007-2]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Universidade de Sao PauloUniversidade de Sao Paul