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Puebla de Zaragoza, Mexico

Gonzalez B.,Institute Investigaciones Farmacologicas | Raineri M.,Institute Investigaciones Farmacologicas | Cadet J.L.,U.S. National Institutes of Health | Garcia-Rill E.,University of Arkansas for Medical Sciences | And 2 more authors.

Chronic use of methamphetamine (METH) leads to long-lasting cognitive dysfunction in humans and in animal models. Modafinil is a wake-promoting compound approved for the treatment of sleeping disorders. It is also prescribed off label to treat METH dependence. In the present study, we investigated whether modafinil could improve cognitive deficits induced by sub-chronic METH treatment in mice by measuring visual retention in a Novel Object Recognition (NOR) task. After sub-chronic METH treatment (1 mg/kg, once a day for 7 days), mice performed the NOR task, which consisted of habituation to the object recognition arena (5 min a day, 3 consecutive days), training session (2 equal objects, 10 min, day 4), and a retention session (1 novel object, 5 min, day 5). One hour before the training session, mice were given a single dose of modafinil (30 or 90 mg/kg). METH-treated mice showed impairments in visual memory retention, evidenced by equal preference of familiar and novel objects during the retention session. The lower dose of modafinil (30 mg/kg) had no effect on visual retention scores in METH-treated mice, while the higher dose (90 mg/kg) rescued visual memory retention to control values. We also measured extracellular signal-regulated kinase (ERK) phosphorylation in medial prefrontal cortex (mPFC), hippocampus, and nucleus accumbens (NAc) of METH- and vehicle-treated mice that received modafinil 1 h before exposure to novel objects in the training session, compared to mice placed in the arena without objects. Elevated ERK phosphorylation was found in the mPFC of vehicle-treated mice, but not in METH-treated mice, exposed to objects. The lower dose of modafinil had no effect on ERK phosphorylation in METH-treated mice, while 90 mg/kg modafinil treatment restored the ERK phosphorylation induced by novelty in METH-treated mice to values comparable to controls. We found neither a novelty nor treatment effect on ERK phosphorylation in hippocampus or NAc of vehicle- and METH-treated mice receiving acute 90 mg/kg modafinil treatment. Our results showed a palliative role of modafinil against METH-induced visual cognitive impairments, possibly by normalizing ERK signaling pathways in mPFC. Modafinil may be a valuable pharmacological tool for the treatment of cognitive deficits observed in human METH abusers as well as in other neuropsychiatric conditions. This article is part of the Special Issue entitled 'CNS Stimulants'. © 2014 Elsevier Ltd. Source

Tenreiro S.,Institute Medicina Molecular | Eckermann K.,University of Gottingen | Outeiro T.F.,Institute Medicina Molecular | Outeiro T.F.,Institute Fisiologia | Outeiro T.F.,University of Gottingen
Frontiers in Molecular Neuroscience

Protein misfolding and aggregation is a common hallmark in neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), and fronto-temporal dementia (FTD). In these disorders, the misfolding and aggregation of specific proteins occurs alongside neuronal degeneration in somewhat specific brain areas, depending on the disorder and the stage of the disease. However, we still do not fully understand the mechanisms governing protein aggregation, and whether this constitutes a protective or detrimental process. In PD, alpha-synuclein (aSyn) forms protein aggregates, known as Lewy bodies, and is phosphorylated at serine 129. Other residues have also been shown to be phosphorylated, but the significance of phosphorylation in the biology and pathophysiology of the protein is still controversial. In AD and in FTD, hyperphosphorylation of tau protein causes its misfolding and aggregation. Again, our understanding of the precise consequences of tau phosphorylation in the biology and pathophysiology of the protein is still limited. Through the use of a variety of model organisms and technical approaches, we are now gaining stronger insight into the effects of phosphorylation in the behavior of these proteins. In this review, we cover recent findings in the field and discuss how targeting phosphorylation events might be used for therapeutic intervention in these devastating diseases of the nervous system. © 2014 Tenreiro, Eckermann and Outeiro. Source

Marques S.,Institute Medicina Molecular | Marques S.,Institute Fisiologia | Marques S.,University of Gottingen | Lopes L.V.,Instituto Of Farmacologia E Neurociencias
Journal of Alzheimer's Disease

Aging is the best-known risk factor for many disorders, including neurodegenerative diseases such as Alzheimer's disease (AD). The effect of epigenetic modulation of gene expression on normal aging and in pathological conditions is still unclear, but it is likely it may explain some of the complexity that is characteristic of these processes. Caffeine is a widely consumed psychoactive drug, which is emerging as a protective agent against AD progression and in aging associated deficits. This occurs mainly through the blockade of adenosine A2A receptors, whose expression and function become aberrant throughout aging and in age-related pathologies. Here, we discuss the data supporting the effects of caffeine in AD, focusing on adenosine A2A receptors and epigenetic modulation of gene expression. In addition, we speculate on the potential of caffeine as an epigenetic modulator and the consequences it might have for preventive and therapeutic applications of caffeine in AD. © 2011 - IOS Press and the authors. All rights reserved. Source

de Oliveira R.M.,Institute Medicina Molecular | Sarkander J.,Institute Medicina Molecular | Kazantsev A.G.,Harvard University | Outeiro T.F.,Institute Medicina Molecular | And 2 more authors.
Frontiers in Pharmacology

Sirtuin proteins are conserved regulators of aging that have recently emerged as important modifiers of several diseases which commonly occur later in life such as cancer, diabetes, cardiovascular, and neurodegenerative diseases. In mammals, there are seven sirtuins (SIRT1-7), which display diversity in subcellular localization and function. SIRT1 has received much of attention due to its possible impact on longevity, while important biological and therapeutic roles of other sirtuins have been underestimated and just recently recognized. Here we focus on SIRT2, a member of the sirtuin family, and discuss its role in cellular and tissue-specific functions. This review summarizes the main scientific advances on SIRT2 protein biology and explores its potential as a therapeutic target for treatment of age-related disorders. © 2012 de Oliveira, Sarkander, Kazantsev and Outeiro. Source

Repici M.,University of Leicester | Straatman K.R.,University of Leicester | Balduccio N.,University of Leicester | Enguita F.J.,Institute Medicina Molecular | And 3 more authors.
Journal of Molecular Medicine

Mutations in the protein DJ-1 cause recessive forms of early onset familial Parkinson's disease (PD). To date, most of the causative mutations studied destabilize formation of DJ-1 homodimers, which appears to be closely linked to its normal function in oxidative stress and other cellular processes. Despite the importance of understanding the dimerization dynamics of this protein, this aspect of DJ-1 biology has not previously been directly studied in living cells. Here, we use bimolecular fluorescence complementation to study DJ-1 dimerization and find not only that DJ-1 forms homodimers in living cells but that most PD causative DJ-1 mutations disrupt this process, including the L166P, M26I, L10P, and P158â̂† mutations. Interestingly, the E64D mutant form of DJ-1 retains the ability to form homodimers. However, while wild-type DJ-1 dimers are stabilized under oxidative stress conditions, we find that the E64D mutation blocks this stabilization. Furthermore, our data show that the E64D mutation potentiates the formation of aggresomes containing DJ-1. We also observe that while the widely studied L166P mutation prevents DJ-1 from forming homodimers or heterodimers with wild-type protein, the mutant protein is able to partially disrupt formation of wild-type homodimers. In summary, by investigating DJ-1 dimerization in living cells, we have uncovered several novel properties of PD causative mutations in DJ-1, which may ultimately provide novel insight into PD pathogenesis and possible therapeutic options. © 2012 The Author(s). Source

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