Melatonin ameliorates A beta(42)-induced alteration of beta APP-processing secretases via the melatonin receptor through the Pin1/GSK3 beta/NF-kappa B pathway in SH-SY5Y cells
JOURNAL OF PINEAL RESEARCH
Authors: Chinchalongporn, Vorapin; Shukla, Mayuri; Govitrapong, Piyarat
Abstract
Melatonin is involved in the physiological regulation of the beta-amyloid precursor protein (beta APP)-cleaving secretases which are responsible for generation of the neurotoxic amyloid beta (A beta) peptide, one of the hallmarks of Alzheimer's disease (AD) pathology. In this study, we aimed to determine the underlying mechanisms of this regulation under pathological conditions. We establish that melatonin prevents A beta(42)-induced downregulation of a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) as well as upregulation of beta-site APP-cleaving enzyme 1 (BACE1) and presenilin 1 (PS1) in SH-SY5Y cell cultures. We also demonstrate that the intrinsic mechanisms of the observed effects occurred via regulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) and glycogen synthase kinase (GSK)-beta 3 as melatonin reversed A beta(42)-induced upregulation and nuclear translocation of NF-kappa Bp65 as well as activation of GSK3 beta via its receptor activation. Furthermore, specific blocking of the NF-kappa B and GSK3 beta pathways partially abrogated the A beta(42)-induced reduction in the BACE1 and PS1 levels. In addition, GSK3 beta blockage affected alpha-secretase cleavage and modulated nuclear translocation of NF-kappa B. Importantly, our study for the first time shows that peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is a crucial target of melatonin. The compromised levels and/or genetic variation of Pin1 are associated with age-dependent tau and A beta pathologies and neuronal degeneration. Interestingly, melatonin alleviated the A beta(42)-induced reduction of nuclear Pin1 levels and preserved the functional integrity of this isomerase. Our findings illustrate that melatonin attenuates A beta(42)-induced alterations of beta APP-cleaving secretases possibly via the Pin1/GSK3 beta/NF-kappa B pathway.
Modulation of the neuronal network activity by P2X receptors and their involvement in neurological disorders
PHARMACOLOGICAL RESEARCH
Authors: Saez-Orellana, F.; Godoy, P. A.; Silva-Grecchi, T.; Barra, K. M.; Fuentealba, J.
Abstract
ATP is a key energetic molecule, fundamental to cell function, which also has an important role in the extracellular milieu as a signaling molecule, acting as a chemoattractant for immune cells and as a neuro- and gliotransmitter. The ionotropic P2X receptors are members of an ATP-gated ion channels family. These ionotropic receptors are widely expressed through the body, with 7 subunits described in mammals, which are arranged in a trimeric configuration with a central pore permeable mainly to Ca2+ and Na+. All 7 subunits are expressed in different brain areas, being present in neurons and glia. ATP, through these ionotropic receptors, can act as a neuromodulator, facilitating the Ca2+-dependent release of neurotransmitters, inducing the cross-inhibition between P2XR and GABA receptors, and exercising by this way a modulation of synaptic plasticity. Growing evidence shows that P2XR play an important role in neuronal disorders and neurodegenerative diseases, like Parkinson's and Alzheimer's disease; this role involves changes on P2XR expression levels, activation of key pathways like GSK3 beta, APP processing, oxidative stress and inflammatory response. This review is focused on the neuromodulatory function of P2XR on pathophysiological conditions of the brain; the recent evidence could open a window to a new therapeutic target. (c) 2015 Elsevier Ltd. All rights reserved.